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[SOURCE: https://en.wikipedia.org/wiki/Balderdash] | [TOKENS: 783] |
Contents Balderdash Balderdash is a board game variant of a classic parlour game known as Fictionary or the Dictionary Game. It was created by Laura Robinson and Paul Toyne of Toronto, Ontario, Canada. The game was first released in 1984 by the Canada Games Company. A US edition appeared that year from TSR, Inc., copyrighted to Gameworks Creations, Inc. and licensed from Canada Games. Subsequent editions have appeared from a variety of companies including The Games Gang, Hasbro and Mattel. The game has sold over 15 million copies worldwide to date. It is aimed at fans of word games, such as Scrabble. Origin Balderdash is based on an earlier game, Fictionary, of essentially similar gameplay, varying in that obscure words are found in an unabridged dictionary instead of the definitions and meanings provided on cards. They are then read out to the unsuspecting individual. The board game version was created by Laura Robinson and Paul Toyne of Toronto, Ontario, Canada. Gameplay The game presents rare and unusual words, and players secretly submit definitions for them, hoping that other players will believe their definition is the real one. It is therefore advantageous to have an excellent vocabulary and the ability to deceive. The game begins by all players rolling a die, with the high roll chosen to be the first "dasher". The dasher draws a "definition card" from the supplied box, and rolls the dice to decide which of the words listed there is to be used. Then the dasher writes the definition of the word (as supplied on the card) on a piece of paper. All other players then write down a definition, which may be an honest attempt to supply the correct definition, or, if they do not know or for tactical reasons decide not to, a fictitious definition for the word designed to sound convincing. The players hand their definitions to the dasher. Players submitting the correct definition are immediately awarded three points, and, if there is more than one, the round is abandoned (though the points are retained). The definitions, including the real definition, are then read out in random order. Players record which answer they believe is correct. Players are awarded two points if they guess the correct definition. Players are awarded one point for each other player who incorrectly chooses the fake definition they wrote. The dasher is awarded three points if no one guesses the correct definition. Players move their tokens around the game board one square for each point awarded. The role of dasher then passes to another player. The winner is the individual whose token reaches the end square first. There are many different variations of ways to break ties (when two or more players hit the end at the same time). One way to resolve a tie is to say all of the players that crossed the finish line won. Another way is to have a sudden death, tie-breaker round where whoever gets more points on the tiebreaker round wins. In 1993, Beyond Balderdash was released. In addition to more up-to-date words, Beyond Balderdash offers obscure acronyms, dates, names, and movie titles, for which the players have to provide full names, major events, major accomplishments, and plot summaries, respectively. The die is used for choosing which category will be chosen from the card. In later editions, the "Major Events" category was switched out for obscure state laws, such as "After midnight in Denver, Colorado, it is illegal to...", with players completing the law. An informal variation of the game consists of the players exclusively submitting hilarious and outrageous definitions. No points are awarded, and the winner is determined by who garnered the most laughs throughout the course of the game. Television version A television game show based on the game aired on Pax TV in 2004 with comedian Elayne Boosler as host. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Internet#cite_note-151] | [TOKENS: 9291] |
Contents Internet The Internet (or internet)[a] is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP)[b] to communicate between networks and devices. It is a network of networks that comprises private, public, academic, business, and government networks of local to global scope, linked by electronic, wireless, and optical networking technologies. The Internet carries a vast range of information services and resources, such as the interlinked hypertext documents and applications of the World Wide Web (WWW), electronic mail, discussion groups, internet telephony, streaming media and file sharing. Most traditional communication media, including telephone, radio, television, paper mail, newspapers, and print publishing, have been transformed by the Internet, giving rise to new media such as email, online music, digital newspapers, news aggregators, and audio and video streaming websites. The Internet has enabled and accelerated new forms of personal interaction through instant messaging, Internet forums, and social networking services. Online shopping has also grown to occupy a significant market across industries, enabling firms to extend brick and mortar presences to serve larger markets. Business-to-business and financial services on the Internet affect supply chains across entire industries. The origins of the Internet date back to research that enabled the time-sharing of computer resources, the development of packet switching, and the design of computer networks for data communication. The set of communication protocols to enable internetworking on the Internet arose from research and development commissioned in the 1970s by the Defense Advanced Research Projects Agency (DARPA) of the United States Department of Defense in collaboration with universities and researchers across the United States and in the United Kingdom and France. The Internet has no single centralized governance in either technological implementation or policies for access and usage. Each constituent network sets its own policies. The overarching definitions of the two principal name spaces on the Internet, the Internet Protocol address (IP address) space and the Domain Name System (DNS), are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN). The technical underpinning and standardization of the core protocols is an activity of the non-profit Internet Engineering Task Force (IETF). Terminology The word internetted was used as early as 1849, meaning interconnected or interwoven. The word Internet was used in 1945 by the United States War Department in a radio operator's manual, and in 1974 as the shorthand form of Internetwork. Today, the term Internet most commonly refers to the global system of interconnected computer networks, though it may also refer to any group of smaller networks. The word Internet may be capitalized as a proper noun, although this is becoming less common. This reflects the tendency in English to capitalize new terms and move them to lowercase as they become familiar. The word is sometimes still capitalized to distinguish the global internet from smaller networks, though many publications, including the AP Stylebook since 2016, recommend the lowercase form in every case. In 2016, the Oxford English Dictionary found that, based on a study of around 2.5 billion printed and online sources, "Internet" was capitalized in 54% of cases. The terms Internet and World Wide Web are often used interchangeably; it is common to speak of "going on the Internet" when using a web browser to view web pages. However, the World Wide Web, or the Web, is only one of a large number of Internet services. It is the global collection of web pages, documents and other web resources linked by hyperlinks and URLs. History In the 1960s, computer scientists began developing systems for time-sharing of computer resources. J. C. R. Licklider proposed the idea of a universal network while working at Bolt Beranek & Newman and, later, leading the Information Processing Techniques Office at the Advanced Research Projects Agency (ARPA) of the United States Department of Defense. Research into packet switching,[c] one of the fundamental Internet technologies, started in the work of Paul Baran at RAND in the early 1960s and, independently, Donald Davies at the United Kingdom's National Physical Laboratory in 1965. After the Symposium on Operating Systems Principles in 1967, packet switching from the proposed NPL network was incorporated into the design of the ARPANET, an experimental resource sharing network proposed by ARPA. ARPANET development began with two network nodes which were interconnected between the University of California, Los Angeles and the Stanford Research Institute on 29 October 1969. The third site was at the University of California, Santa Barbara, followed by the University of Utah. By the end of 1971, 15 sites were connected to the young ARPANET. Thereafter, the ARPANET gradually developed into a decentralized communications network, connecting remote centers and military bases in the United States. Other user networks and research networks, such as the Merit Network and CYCLADES, were developed in the late 1960s and early 1970s. Early international collaborations for the ARPANET were rare. Connections were made in 1973 to Norway (NORSAR and, later, NDRE) and to Peter Kirstein's research group at University College London, which provided a gateway to British academic networks, the first internetwork for resource sharing. ARPA projects, the International Network Working Group and commercial initiatives led to the development of various protocols and standards by which multiple separate networks could become a single network, or a network of networks. In 1974, Vint Cerf at Stanford University and Bob Kahn at DARPA published a proposal for "A Protocol for Packet Network Intercommunication". Cerf and his graduate students used the term internet as a shorthand for internetwork in RFC 675. The Internet Experiment Notes and later RFCs repeated this use. The work of Louis Pouzin and Robert Metcalfe had important influences on the resulting TCP/IP design. National PTTs and commercial providers developed the X.25 standard and deployed it on public data networks. The ARPANET initially served as a backbone for the interconnection of regional academic and military networks in the United States to enable resource sharing. Access to the ARPANET was expanded in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). In 1982, the Internet Protocol Suite (TCP/IP) was standardized, which facilitated worldwide proliferation of interconnected networks. TCP/IP network access expanded again in 1986 when the National Science Foundation Network (NSFNet) provided access to supercomputer sites in the United States for researchers, first at speeds of 56 kbit/s and later at 1.5 Mbit/s and 45 Mbit/s. The NSFNet expanded into academic and research organizations in Europe, Australia, New Zealand and Japan in 1988–89. Although other network protocols such as UUCP and PTT public data networks had global reach well before this time, this marked the beginning of the Internet as an intercontinental network. Commercial Internet service providers emerged in 1989 in the United States and Australia. The ARPANET was decommissioned in 1990. The linking of commercial networks and enterprises by the early 1990s, as well as the advent of the World Wide Web, marked the beginning of the transition to the modern Internet. Steady advances in semiconductor technology and optical networking created new economic opportunities for commercial involvement in the expansion of the network in its core and for delivering services to the public. In mid-1989, MCI Mail and Compuserve established connections to the Internet, delivering email and public access products to the half million users of the Internet. Just months later, on 1 January 1990, PSInet launched an alternate Internet backbone for commercial use; one of the networks that added to the core of the commercial Internet of later years. In March 1990, the first high-speed T1 (1.5 Mbit/s) link between the NSFNET and Europe was installed between Cornell University and CERN, allowing much more robust communications than were capable with satellites. Later in 1990, Tim Berners-Lee began writing WorldWideWeb, the first web browser, after two years of lobbying CERN management. By Christmas 1990, Berners-Lee had built all the tools necessary for a working Web: the HyperText Transfer Protocol (HTTP) 0.9, the HyperText Markup Language (HTML), the first Web browser (which was also an HTML editor and could access Usenet newsgroups and FTP files), the first HTTP server software (later known as CERN httpd), the first web server, and the first Web pages that described the project itself. In 1991 the Commercial Internet eXchange was founded, allowing PSInet to communicate with the other commercial networks CERFnet and Alternet. Stanford Federal Credit Union was the first financial institution to offer online Internet banking services to all of its members in October 1994. In 1996, OP Financial Group, also a cooperative bank, became the second online bank in the world and the first in Europe. By 1995, the Internet was fully commercialized in the U.S. when the NSFNet was decommissioned, removing the last restrictions on use of the Internet to carry commercial traffic. As technology advanced and commercial opportunities fueled reciprocal growth, the volume of Internet traffic started experiencing similar characteristics as that of the scaling of MOS transistors, exemplified by Moore's law, doubling every 18 months. This growth, formalized as Edholm's law, was catalyzed by advances in MOS technology, laser light wave systems, and noise performance. Since 1995, the Internet has tremendously impacted culture and commerce, including the rise of near-instant communication by email, instant messaging, telephony (Voice over Internet Protocol or VoIP), two-way interactive video calls, and the World Wide Web. Increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1 Gbit/s, 10 Gbit/s, or more. The Internet continues to grow, driven by ever-greater amounts of online information and knowledge, commerce, entertainment and social networking services. During the late 1990s, it was estimated that traffic on the public Internet grew by 100 percent per year, while the mean annual growth in the number of Internet users was thought to be between 20% and 50%. This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network. In November 2006, the Internet was included on USA Today's list of the New Seven Wonders. As of 31 March 2011[update], the estimated total number of Internet users was 2.095 billion (30% of world population). It is estimated that in 1993 the Internet carried only 1% of the information flowing through two-way telecommunication. By 2000 this figure had grown to 51%, and by 2007 more than 97% of all telecommunicated information was carried over the Internet. Modern smartphones can access the Internet through cellular carrier networks, and internet usage by mobile and tablet devices exceeded desktop worldwide for the first time in October 2016. As of 2018[update], 80% of the world's population were covered by a 4G network. The International Telecommunication Union (ITU) estimated that, by the end of 2017, 48% of individual users regularly connect to the Internet, up from 34% in 2012. Mobile Internet connectivity has played an important role in expanding access in recent years, especially in Asia and the Pacific and in Africa. The number of unique mobile cellular subscriptions increased from 3.9 billion in 2012 to 4.8 billion in 2016, two-thirds of the world's population, with more than half of subscriptions located in Asia and the Pacific. The limits that users face on accessing information via mobile applications coincide with a broader process of fragmentation of the Internet. Fragmentation restricts access to media content and tends to affect the poorest users the most. One solution, zero-rating, is the practice of Internet service providers allowing users free connectivity to access specific content or applications without cost. Social impact The Internet has enabled new forms of social interaction, activities, and social associations, giving rise to the scholarly study of the sociology of the Internet. Between 2000 and 2009, the number of Internet users globally rose from 390 million to 1.9 billion. By 2010, 22% of the world's population had access to computers with 1 billion Google searches every day, 300 million Internet users reading blogs, and 2 billion videos viewed daily on YouTube. In 2014 the world's Internet users surpassed 3 billion or 44 percent of world population, but two-thirds came from the richest countries, with 78 percent of Europeans using the Internet, followed by 57 percent of the Americas. However, by 2018, Asia alone accounted for 51% of all Internet users, with 2.2 billion out of the 4.3 billion Internet users in the world. China's Internet users surpassed a major milestone in 2018, when the country's Internet regulatory authority, China Internet Network Information Centre, announced that China had 802 million users. China was followed by India, with some 700 million users, with the United States third with 275 million users. However, in terms of penetration, in 2022, China had a 70% penetration rate compared to India's 60% and the United States's 90%. In 2022, 54% of the world's Internet users were based in Asia, 14% in Europe, 7% in North America, 10% in Latin America and the Caribbean, 11% in Africa, 4% in the Middle East and 1% in Oceania. In 2019, Kuwait, Qatar, the Falkland Islands, Bermuda and Iceland had the highest Internet penetration by the number of users, with 93% or more of the population with access. As of 2022, it was estimated that 5.4 billion people use the Internet, more than two-thirds of the world's population. Early computer systems were limited to the characters in the American Standard Code for Information Interchange (ASCII), a subset of the Latin alphabet. After English (27%), the most requested languages on the World Wide Web are Chinese (25%), Spanish (8%), Japanese (5%), Portuguese and German (4% each), Arabic, French and Russian (3% each), and Korean (2%). Modern character encoding standards, such as Unicode, allow for development and communication in the world's widely used languages. However, some glitches such as mojibake (incorrect display of some languages' characters) still remain. Several neologisms exist that refer to Internet users: Netizen (as in "citizen of the net") refers to those actively involved in improving online communities, the Internet in general or surrounding political affairs and rights such as free speech, Internaut refers to operators or technically highly capable users of the Internet, digital citizen refers to a person using the Internet in order to engage in society, politics, and government participation. The Internet allows greater flexibility in working hours and location, especially with the spread of unmetered high-speed connections. The Internet can be accessed almost anywhere by numerous means, including through mobile Internet devices. Mobile phones, datacards, handheld game consoles and cellular routers allow users to connect to the Internet wirelessly.[citation needed] Educational material at all levels from pre-school (e.g. CBeebies) to post-doctoral (e.g. scholarly literature through Google Scholar) is available on websites. The internet has facilitated the development of virtual universities and distance education, enabling both formal and informal education. The Internet allows researchers to conduct research remotely via virtual laboratories, with profound changes in reach and generalizability of findings as well as in communication between scientists and in the publication of results. By the late 2010s the Internet had been described as "the main source of scientific information "for the majority of the global North population".: 111 Wikis have also been used in the academic community for sharing and dissemination of information across institutional and international boundaries. In those settings, they have been found useful for collaboration on grant writing, strategic planning, departmental documentation, and committee work. The United States Patent and Trademark Office uses a wiki to allow the public to collaborate on finding prior art relevant to examination of pending patent applications. Queens, New York has used a wiki to allow citizens to collaborate on the design and planning of a local park. The English Wikipedia has the largest user base among wikis on the World Wide Web and ranks in the top 10 among all sites in terms of traffic. The Internet has been a major outlet for leisure activity since its inception, with entertaining social experiments such as MUDs and MOOs being conducted on university servers, and humor-related Usenet groups receiving much traffic. Many Internet forums have sections devoted to games and funny videos. Another area of leisure activity on the Internet is multiplayer gaming. This form of recreation creates communities, where people of all ages and origins enjoy the fast-paced world of multiplayer games. These range from MMORPG to first-person shooters, from role-playing video games to online gambling. While online gaming has been around since the 1970s, modern modes of online gaming began with subscription services such as GameSpy and MPlayer. Streaming media is the real-time delivery of digital media for immediate consumption or enjoyment by end users. Streaming companies (such as Netflix, Disney+, Amazon's Prime Video, Mubi, Hulu, and Apple TV+) now dominate the entertainment industry, eclipsing traditional broadcasters. Audio streamers such as Spotify and Apple Music also have significant market share in the audio entertainment market. Video sharing websites are also a major factor in the entertainment ecosystem. YouTube was founded on 15 February 2005 and is now the leading website for free streaming video with more than two billion users. It uses a web player to stream and show video files. YouTube users watch hundreds of millions, and upload hundreds of thousands, of videos daily. Other video sharing websites include Vimeo, Instagram and TikTok.[citation needed] Although many governments have attempted to restrict both Internet pornography and online gambling, this has generally failed to stop their widespread popularity. A number of advertising-funded ostensible video sharing websites known as "tube sites" have been created to host shared pornographic video content. Due to laws requiring the documentation of the origin of pornography, these websites now largely operate in conjunction with pornographic movie studios and their own independent creator networks, acting as de-facto video streaming services. Major players in this field include the market leader Aylo, the operator of PornHub and numerous other branded sites, as well as other independent operators such as xHamster and Xvideos. As of 2023[update], Internet traffic to pornographic video sites rivalled that of mainstream video streaming and sharing services. Remote work is facilitated by tools such as groupware, virtual private networks, conference calling, videotelephony, and VoIP so that work may be performed from any location, such as the worker's home.[citation needed] The spread of low-cost Internet access in developing countries has opened up new possibilities for peer-to-peer charities, which allow individuals to contribute small amounts to charitable projects for other individuals. Websites, such as DonorsChoose and GlobalGiving, allow small-scale donors to direct funds to individual projects of their choice. A popular twist on Internet-based philanthropy is the use of peer-to-peer lending for charitable purposes. Kiva pioneered this concept in 2005, offering the first web-based service to publish individual loan profiles for funding. The low cost and nearly instantaneous sharing of ideas, knowledge, and skills have made collaborative work dramatically easier, with the help of collaborative software, which allow groups to easily form, cheaply communicate, and share ideas. An example of collaborative software is the free software movement, which has produced, among other things, Linux, Mozilla Firefox, and OpenOffice.org (later forked into LibreOffice).[citation needed] Content management systems allow collaborating teams to work on shared sets of documents simultaneously without accidentally destroying each other's work.[citation needed] The internet also allows for cloud computing, virtual private networks, remote desktops, and remote work.[citation needed] The online disinhibition effect describes the tendency of many individuals to behave more stridently or offensively online than they would in person. A significant number of feminist women have been the target of various forms of harassment, including insults and hate speech, to, in extreme cases, rape and death threats, in response to posts they have made on social media. Social media companies have been criticized in the past for not doing enough to aid victims of online abuse. Children also face dangers online such as cyberbullying and approaches by sexual predators, who sometimes pose as children themselves. Due to naivety, they may also post personal information about themselves online, which could put them or their families at risk unless warned not to do so. Many parents choose to enable Internet filtering or supervise their children's online activities in an attempt to protect their children from pornography or violent content on the Internet. The most popular social networking services commonly forbid users under the age of 13. However, these policies can be circumvented by registering an account with a false birth date, and a significant number of children aged under 13 join such sites.[citation needed] Social networking services for younger children, which claim to provide better levels of protection for children, also exist. Internet usage has been correlated to users' loneliness. Lonely people tend to use the Internet as an outlet for their feelings and to share their stories with others, such as in the "I am lonely will anyone speak to me" thread.[citation needed] Cyberslacking can become a drain on corporate resources; employees spend a significant amount of time surfing the Web while at work. Internet addiction disorder is excessive computer use that interferes with daily life. Nicholas G. Carr believes that Internet use has other effects on individuals, for instance improving skills of scan-reading and interfering with the deep thinking that leads to true creativity. Electronic business encompasses business processes spanning the entire value chain: purchasing, supply chain management, marketing, sales, customer service, and business relationship. E-commerce seeks to add revenue streams using the Internet to build and enhance relationships with clients and partners. According to International Data Corporation, the size of worldwide e-commerce, when global business-to-business and -consumer transactions are combined, equate to $16 trillion in 2013. A report by Oxford Economics added those two together to estimate the total size of the digital economy at $20.4 trillion, equivalent to roughly 13.8% of global sales. While much has been written of the economic advantages of Internet-enabled commerce, there is also evidence that some aspects of the Internet such as maps and location-aware services may serve to reinforce economic inequality and the digital divide. Electronic commerce may be responsible for consolidation and the decline of mom-and-pop, brick and mortar businesses resulting in increases in income inequality. A 2013 Institute for Local Self-Reliance report states that brick-and-mortar retailers employ 47 people for every $10 million in sales, while Amazon employs only 14. Similarly, the 700-employee room rental start-up Airbnb was valued at $10 billion in 2014, about half as much as Hilton Worldwide, which employs 152,000 people. At that time, Uber employed 1,000 full-time employees and was valued at $18.2 billion, about the same valuation as Avis Rent a Car and The Hertz Corporation combined, which together employed almost 60,000 people. Advertising on popular web pages can be lucrative, and e-commerce. Online advertising is a form of marketing and advertising which uses the Internet to deliver promotional marketing messages to consumers. It includes email marketing, search engine marketing (SEM), social media marketing, many types of display advertising (including web banner advertising), and mobile advertising. In 2011, Internet advertising revenues in the United States surpassed those of cable television and nearly exceeded those of broadcast television.: 19 Many common online advertising practices are controversial and increasingly subject to regulation. The Internet has achieved new relevance as a political tool. The presidential campaign of Howard Dean in 2004 in the United States was notable for its success in soliciting donation via the Internet. Many political groups use the Internet to achieve a new method of organizing for carrying out their mission, having given rise to Internet activism. Social media websites, such as Facebook and Twitter, helped people organize the Arab Spring, by helping activists organize protests, communicate grievances, and disseminate information. Many have understood the Internet as an extension of the Habermasian notion of the public sphere, observing how network communication technologies provide something like a global civic forum. However, incidents of politically motivated Internet censorship have now been recorded in many countries, including western democracies. E-government is the use of technological communications devices, such as the Internet, to provide public services to citizens and other persons in a country or region. E-government offers opportunities for more direct and convenient citizen access to government and for government provision of services directly to citizens. Cybersectarianism is a new organizational form that involves: highly dispersed small groups of practitioners that may remain largely anonymous within the larger social context and operate in relative secrecy, while still linked remotely to a larger network of believers who share a set of practices and texts, and often a common devotion to a particular leader. Overseas supporters provide funding and support; domestic practitioners distribute tracts, participate in acts of resistance, and share information on the internal situation with outsiders. Collectively, members and practitioners of such sects construct viable virtual communities of faith, exchanging personal testimonies and engaging in the collective study via email, online chat rooms, and web-based message boards. In particular, the British government has raised concerns about the prospect of young British Muslims being indoctrinated into Islamic extremism by material on the Internet, being persuaded to join terrorist groups such as the so-called "Islamic State", and then potentially committing acts of terrorism on returning to Britain after fighting in Syria or Iraq.[citation needed] Applications and services The Internet carries many applications and services, most prominently the World Wide Web, including social media, electronic mail, mobile applications, multiplayer online games, Internet telephony, file sharing, and streaming media services. The World Wide Web is a global collection of documents, images, multimedia, applications, and other resources, logically interrelated by hyperlinks and referenced with Uniform Resource Identifiers (URIs), which provide a global system of named references. URIs symbolically identify services, web servers, databases, and the documents and resources that they can provide. HyperText Transfer Protocol (HTTP) is the main access protocol of the World Wide Web. Web services also use HTTP for communication between software systems for information transfer, sharing and exchanging business data and logistics and is one of many languages or protocols that can be used for communication on the Internet. World Wide Web browser software, such as Microsoft Edge, Mozilla Firefox, Opera, Apple's Safari, and Google Chrome, enable users to navigate from one web page to another via the hyperlinks embedded in the documents. These documents may also contain computer data, including graphics, sounds, text, video, multimedia and interactive content. Client-side scripts can include animations, games, office applications and scientific demonstrations. Email is an important communications service available via the Internet. The concept of sending electronic text messages between parties, analogous to mailing letters or memos, predates the creation of the Internet. Internet telephony is a common communications service realized with the Internet. The name of the principal internetworking protocol, the Internet Protocol, lends its name to voice over Internet Protocol (VoIP).[citation needed] VoIP systems now dominate many markets, being as easy and convenient as a traditional telephone, while having substantial cost savings, especially over long distances. File sharing is the practice of transferring large amounts of data in the form of computer files across the Internet, for example via file servers. The load of bulk downloads to many users can be eased by the use of "mirror" servers or peer-to-peer networks. Access to the file may be controlled by user authentication, the transit of the file over the Internet may be obscured by encryption, and money may change hands for access to the file. The price can be paid by the remote charging of funds from, for example, a credit card whose details are also passed—usually fully encrypted—across the Internet. The origin and authenticity of the file received may be checked by a digital signature. Governance The Internet is a global network that comprises many voluntarily interconnected autonomous networks. It operates without a central governing body. The technical underpinning and standardization of the core protocols (IPv4 and IPv6) is an activity of the Internet Engineering Task Force (IETF), a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise. While the hardware components in the Internet infrastructure can often be used to support other software systems, it is the design and the standardization process of the software that characterizes the Internet and provides the foundation for its scalability and success. The responsibility for the architectural design of the Internet software systems has been assumed by the IETF. The IETF conducts standard-setting work groups, open to any individual, about the various aspects of Internet architecture. The resulting contributions and standards are published as Request for Comments (RFC) documents on the IETF web site. The principal methods of networking that enable the Internet are contained in specially designated RFCs that constitute the Internet Standards. Other less rigorous documents are simply informative, experimental, or historical, or document the best current practices when implementing Internet technologies. To maintain interoperability, the principal name spaces of the Internet are administered by the Internet Corporation for Assigned Names and Numbers (ICANN). ICANN is governed by an international board of directors drawn from across the Internet technical, business, academic, and other non-commercial communities. The organization coordinates the assignment of unique identifiers for use on the Internet, including domain names, IP addresses, application port numbers in the transport protocols, and many other parameters. Globally unified name spaces are essential for maintaining the global reach of the Internet. This role of ICANN distinguishes it as perhaps the only central coordinating body for the global Internet. The National Telecommunications and Information Administration, an agency of the United States Department of Commerce, had final approval over changes to the DNS root zone until the IANA stewardship transition on 1 October 2016. Regional Internet registries (RIRs) were established for five regions of the world to assign IP address blocks and other Internet parameters to local registries, such as Internet service providers, from a designated pool of addresses set aside for each region:[citation needed] The Internet Society (ISOC) was founded in 1992 with a mission to "assure the open development, evolution and use of the Internet for the benefit of all people throughout the world". Its members include individuals as well as corporations, organizations, governments, and universities. Among other activities ISOC provides an administrative home for a number of less formally organized groups that are involved in developing and managing the Internet, including: the Internet Engineering Task Force (IETF), Internet Architecture Board (IAB), Internet Engineering Steering Group (IESG), Internet Research Task Force (IRTF), and Internet Research Steering Group (IRSG). On 16 November 2005, the United Nations-sponsored World Summit on the Information Society in Tunis established the Internet Governance Forum (IGF) to discuss Internet-related issues.[citation needed] Infrastructure The communications infrastructure of the Internet consists of its hardware components and a system of software layers that control various aspects of the architecture. As with any computer network, the Internet physically consists of routers, media (such as cabling and radio links), repeaters, and modems. However, as an example of internetworking, many of the network nodes are not necessarily Internet equipment per se. Internet packets are carried by other full-fledged networking protocols, with the Internet acting as a homogeneous networking standard, running across heterogeneous hardware, with the packets guided to their destinations by IP routers.[citation needed] Internet service providers (ISPs) establish worldwide connectivity between individual networks at various levels of scope. At the top of the routing hierarchy are the tier 1 networks, large telecommunication companies that exchange traffic directly with each other via very high speed fiber-optic cables and governed by peering agreements. Tier 2 and lower-level networks buy Internet transit from other providers to reach at least some parties on the global Internet, though they may also engage in peering. End-users who only access the Internet when needed to perform a function or obtain information, represent the bottom of the routing hierarchy.[citation needed] An ISP may use a single upstream provider for connectivity, or implement multihoming to achieve redundancy and load balancing. Internet exchange points are major traffic exchanges with physical connections to multiple ISPs. Large organizations, such as academic institutions, large enterprises, and governments, may perform the same function as ISPs, engaging in peering and purchasing transit on behalf of their internal networks. Research networks tend to interconnect with large subnetworks such as GEANT, GLORIAD, Internet2, and the UK's national research and education network, JANET.[citation needed] Common methods of Internet access by users include broadband over coaxial cable, fiber optics or copper wires, Wi-Fi, satellite, and cellular telephone technology.[citation needed] Grassroots efforts have led to wireless community networks. Commercial Wi-Fi services that cover large areas are available in many cities, such as New York, London, Vienna, Toronto, San Francisco, Philadelphia, Chicago and Pittsburgh. Most servers that provide internet services are today hosted in data centers, and content is often accessed through high-performance content delivery networks. Colocation centers often host private peering connections between their customers, internet transit providers, cloud providers, meet-me rooms for connecting customers together, Internet exchange points, and landing points and terminal equipment for fiber optic submarine communication cables, connecting the internet. Internet Protocol Suite The Internet standards describe a framework known as the Internet protocol suite (also called TCP/IP, based on the first two components.) This is a suite of protocols that are ordered into a set of four conceptional layers by the scope of their operation, originally documented in RFC 1122 and RFC 1123:[citation needed] The most prominent component of the Internet model is the Internet Protocol. IP enables internetworking, essentially establishing the Internet itself. Two versions of the Internet Protocol exist, IPv4 and IPv6.[citation needed] Aside from the complex array of physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contracts (e.g., peering agreements), and by technical specifications or protocols that describe the exchange of data over the network.[citation needed] For locating individual computers on the network, the Internet provides IP addresses. IP addresses are used by the Internet infrastructure to direct internet packets to their destinations. They consist of fixed-length numbers, which are found within the packet. IP addresses are generally assigned to equipment either automatically via Dynamic Host Configuration Protocol, or are configured.[citation needed] Domain Name Systems convert user-inputted domain names (e.g. "en.wikipedia.org") into IP addresses.[citation needed] Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit number. IPv4 is the initial version used on the first generation of the Internet and is still in dominant use. It was designed in 1981 to address up to ≈4.3 billion (109) hosts. However, the explosive growth of the Internet has led to IPv4 address exhaustion, which entered its final stage in 2011, when the global IPv4 address allocation pool was exhausted. Because of the growth of the Internet and the depletion of available IPv4 addresses, a new version of IP IPv6, was developed in the mid-1990s, which provides vastly larger addressing capabilities and more efficient routing of Internet traffic. IPv6 uses 128 bits for the IP address and was standardized in 1998. IPv6 deployment has been ongoing since the mid-2000s and is currently in growing deployment around the world, since Internet address registries began to urge all resource managers to plan rapid adoption and conversion. By design, IPv6 is not directly interoperable with IPv4. Instead, it establishes a parallel version of the Internet not directly accessible with IPv4 software. Thus, translation facilities exist for internetworking, and some nodes have duplicate networking software for both networks. Essentially all modern computer operating systems support both versions of the Internet Protocol.[citation needed] Network infrastructure, however, has been lagging in this development.[citation needed] A subnet or subnetwork is a logical subdivision of an IP network.: 1, 16 Computers that belong to a subnet are addressed with an identical most-significant bit-group in their IP addresses. This results in the logical division of an IP address into two fields, the network number or routing prefix and the rest field or host identifier. The rest field is an identifier for a specific host or network interface.[citation needed] The routing prefix may be expressed in Classless Inter-Domain Routing (CIDR) notation written as the first address of a network, followed by a slash character (/), and ending with the bit-length of the prefix. For example, 198.51.100.0/24 is the prefix of the Internet Protocol version 4 network starting at the given address, having 24 bits allocated for the network prefix, and the remaining 8 bits reserved for host addressing. Addresses in the range 198.51.100.0 to 198.51.100.255 belong to this network. The IPv6 address specification 2001:db8::/32 is a large address block with 296 addresses, having a 32-bit routing prefix.[citation needed] For IPv4, a network may also be characterized by its subnet mask or netmask, which is the bitmask that when applied by a bitwise AND operation to any IP address in the network, yields the routing prefix. Subnet masks are also expressed in dot-decimal notation like an address. For example, 255.255.255.0 is the subnet mask for the prefix 198.51.100.0/24.[citation needed] Computers and routers use routing tables in their operating system to forward IP packets to reach a node on a different subnetwork. Routing tables are maintained by manual configuration or automatically by routing protocols. End-nodes typically use a default route that points toward an ISP providing transit, while ISP routers use the Border Gateway Protocol to establish the most efficient routing across the complex connections of the global Internet.[citation needed] The default gateway is the node that serves as the forwarding host (router) to other networks when no other route specification matches the destination IP address of a packet. Security Internet resources, hardware, and software components are the target of criminal or malicious attempts to gain unauthorized control to cause interruptions, commit fraud, engage in blackmail or access private information. Malware is malicious software used and distributed via the Internet. It includes computer viruses which are copied with the help of humans, computer worms which copy themselves automatically, software for denial of service attacks, ransomware, botnets, and spyware that reports on the activity and typing of users.[citation needed] Usually, these activities constitute cybercrime. Defense theorists have also speculated about the possibilities of hackers using cyber warfare using similar methods on a large scale. Malware poses serious problems to individuals and businesses on the Internet. According to Symantec's 2018 Internet Security Threat Report (ISTR), malware variants number has increased to 669,947,865 in 2017, which is twice as many malware variants as in 2016. Cybercrime, which includes malware attacks as well as other crimes committed by computer, was predicted to cost the world economy US$6 trillion in 2021, and is increasing at a rate of 15% per year. Since 2021, malware has been designed to target computer systems that run critical infrastructure such as the electricity distribution network. Malware can be designed to evade antivirus software detection algorithms. The vast majority of computer surveillance involves the monitoring of data and traffic on the Internet. In the United States for example, under the Communications Assistance For Law Enforcement Act, all phone calls and broadband Internet traffic (emails, web traffic, instant messaging, etc.) are required to be available for unimpeded real-time monitoring by Federal law enforcement agencies. Under the Act, all U.S. telecommunications providers are required to install packet sniffing technology to allow Federal law enforcement and intelligence agencies to intercept all of their customers' broadband Internet and VoIP traffic.[d] The large amount of data gathered from packet capture requires surveillance software that filters and reports relevant information, such as the use of certain words or phrases, the access to certain types of web sites, or communicating via email or chat with certain parties. Agencies, such as the Information Awareness Office, NSA, GCHQ and the FBI, spend billions of dollars per year to develop, purchase, implement, and operate systems for interception and analysis of data. Similar systems are operated by Iranian secret police to identify and suppress dissidents. The required hardware and software were allegedly installed by German Siemens AG and Finnish Nokia. Some governments, such as those of Myanmar, Iran, North Korea, Mainland China, Saudi Arabia and the United Arab Emirates, restrict access to content on the Internet within their territories, especially to political and religious content, with domain name and keyword filters. In Norway, Denmark, Finland, and Sweden, major Internet service providers have voluntarily agreed to restrict access to sites listed by authorities. While this list of forbidden resources is supposed to contain only known child pornography sites, the content of the list is secret. Many countries, including the United States, have enacted laws against the possession or distribution of certain material, such as child pornography, via the Internet but do not mandate filter software. Many free or commercially available software programs, called content-control software are available to users to block offensive specific on individual computers or networks in order to limit access by children to pornographic material or depiction of violence.[citation needed] Performance As the Internet is a heterogeneous network, its physical characteristics, including, for example the data transfer rates of connections, vary widely. It exhibits emergent phenomena that depend on its large-scale organization. PB per monthYear020,00040,00060,00080,000100,000120,000140,000199019952000200520102015Petabytes per monthGlobal Internet Traffic Volume The volume of Internet traffic is difficult to measure because no single point of measurement exists in the multi-tiered, non-hierarchical topology. Traffic data may be estimated from the aggregate volume through the peering points of the Tier 1 network providers, but traffic that stays local in large provider networks may not be accounted for.[citation needed] An Internet blackout or outage can be caused by local signaling interruptions. Disruptions of submarine communications cables may cause blackouts or slowdowns to large areas, such as in the 2008 submarine cable disruption. Less-developed countries are more vulnerable due to the small number of high-capacity links. Land cables are also vulnerable, as in 2011 when a woman digging for scrap metal severed most connectivity for the nation of Armenia. Internet blackouts affecting almost entire countries can be achieved by governments as a form of Internet censorship, as in the blockage of the Internet in Egypt, whereby approximately 93% of networks were without access in 2011 in an attempt to stop mobilization for anti-government protests. Estimates of the Internet's electricity usage have been the subject of controversy, according to a 2014 peer-reviewed research paper that found claims differing by a factor of 20,000 published in the literature during the preceding decade, ranging from 0.0064 kilowatt hours per gigabyte transferred (kWh/GB) to 136 kWh/GB. The researchers attributed these discrepancies mainly to the year of reference (i.e. whether efficiency gains over time had been taken into account) and to whether "end devices such as personal computers and servers are included" in the analysis. In 2011, academic researchers estimated the overall energy used by the Internet to be between 170 and 307 GW, less than two percent of the energy used by humanity. This estimate included the energy needed to build, operate, and periodically replace the estimated 750 million laptops, a billion smart phones and 100 million servers worldwide as well as the energy that routers, cell towers, optical switches, Wi-Fi transmitters and cloud storage devices use when transmitting Internet traffic. According to a non-peer-reviewed study published in 2018 by The Shift Project (a French think tank funded by corporate sponsors), nearly 4% of global CO2 emissions could be attributed to global data transfer and the necessary infrastructure. The study also said that online video streaming alone accounted for 60% of this data transfer and therefore contributed to over 300 million tons of CO2 emission per year, and argued for new "digital sobriety" regulations restricting the use and size of video files. See also Notes References Sources Further reading External links |
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Contents Elon Musk Elon Reeve Musk (/ˈiːlɒn/ EE-lon; born June 28, 1971) is a businessman and entrepreneur known for his leadership of Tesla, SpaceX, Twitter, and xAI. Musk has been the wealthiest person in the world since 2025; as of February 2026,[update] Forbes estimates his net worth to be around US$852 billion. Born into a wealthy family in Pretoria, South Africa, Musk emigrated in 1989 to Canada; he has Canadian citizenship since his mother was born there. He received bachelor's degrees in 1997 from the University of Pennsylvania before moving to California to pursue business ventures. In 1995, Musk co-founded the software company Zip2. Following its sale in 1999, he co-founded X.com, an online payment company that later merged to form PayPal, which was acquired by eBay in 2002. Musk also became an American citizen in 2002. In 2002, Musk founded the space technology company SpaceX, becoming its CEO and chief engineer; the company has since led innovations in reusable rockets and commercial spaceflight. Musk joined the automaker Tesla as an early investor in 2004 and became its CEO and product architect in 2008; it has since become a leader in electric vehicles. In 2015, he co-founded OpenAI to advance artificial intelligence (AI) research, but later left; growing discontent with the organization's direction and their leadership in the AI boom in the 2020s led him to establish xAI, which became a subsidiary of SpaceX in 2026. In 2022, he acquired the social network Twitter, implementing significant changes, and rebranding it as X in 2023. His other businesses include the neurotechnology company Neuralink, which he co-founded in 2016, and the tunneling company the Boring Company, which he founded in 2017. In November 2025, a Tesla pay package worth $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Musk was the largest donor in the 2024 U.S. presidential election, where he supported Donald Trump. After Trump was inaugurated as president in early 2025, Musk served as Senior Advisor to the President and as the de facto head of the Department of Government Efficiency (DOGE). After a public feud with Trump, Musk left the Trump administration and returned to managing his companies. Musk is a supporter of global far-right figures, causes, and political parties. His political activities, views, and statements have made him a polarizing figure. Musk has been criticized for COVID-19 misinformation, promoting conspiracy theories, and affirming antisemitic, racist, and transphobic comments. His acquisition of Twitter was controversial due to a subsequent increase in hate speech and the spread of misinformation on the service, following his pledge to decrease censorship. His role in the second Trump administration attracted public backlash, particularly in response to DOGE. The emails he sent to Jeffrey Epstein are included in the Epstein files, which were published between 2025–26 and became a topic of worldwide debate. Early life Elon Reeve Musk was born on June 28, 1971, in Pretoria, South Africa's administrative capital. He is of British and Pennsylvania Dutch ancestry. His mother, Maye (née Haldeman), is a model and dietitian born in Saskatchewan, Canada, and raised in South Africa. Musk therefore holds both South African and Canadian citizenship from birth. His father, Errol Musk, is a South African electromechanical engineer, pilot, sailor, consultant, emerald dealer, and property developer, who partly owned a rental lodge at Timbavati Private Nature Reserve. His maternal grandfather, Joshua N. Haldeman, who died in a plane crash when Elon was a toddler, was an American-born Canadian chiropractor, aviator and political activist in the technocracy movement who moved to South Africa in 1950. Elon has a younger brother, Kimbal, a younger sister, Tosca, and four paternal half-siblings. Musk was baptized as a child in the Anglican Church of Southern Africa. Despite both Elon and Errol previously stating that Errol was a part owner of a Zambian emerald mine, in 2023, Errol recounted that the deal he made was to receive "a portion of the emeralds produced at three small mines". Errol was elected to the Pretoria City Council as a representative of the anti-apartheid Progressive Party and has said that his children shared their father's dislike of apartheid. After his parents divorced in 1979, Elon, aged around 9, chose to live with his father because Errol Musk had an Encyclopædia Britannica and a computer. Elon later regretted his decision and became estranged from his father. Elon has recounted trips to a wilderness school that he described as a "paramilitary Lord of the Flies" where "bullying was a virtue" and children were encouraged to fight over rations. In one incident, after an altercation with a fellow pupil, Elon was thrown down concrete steps and beaten severely, leading to him being hospitalized for his injuries. Elon described his father berating him after he was discharged from the hospital. Errol denied berating Elon and claimed, "The [other] boy had just lost his father to suicide, and Elon had called him stupid. Elon had a tendency to call people stupid. How could I possibly blame that child?" Elon was an enthusiastic reader of books, and had attributed his success in part to having read The Lord of the Rings, the Foundation series, and The Hitchhiker's Guide to the Galaxy. At age ten, he developed an interest in computing and video games, teaching himself how to program from the VIC-20 user manual. At age twelve, Elon sold his BASIC-based game Blastar to PC and Office Technology magazine for approximately $500 (equivalent to $1,600 in 2025). Musk attended Waterkloof House Preparatory School, Bryanston High School, and then Pretoria Boys High School, where he graduated. Musk was a decent but unexceptional student, earning a 61/100 in Afrikaans and a B on his senior math certification. Musk applied for a Canadian passport through his Canadian-born mother to avoid South Africa's mandatory military service, which would have forced him to participate in the apartheid regime, as well as to ease his path to immigration to the United States. While waiting for his application to be processed, he attended the University of Pretoria for five months. Musk arrived in Canada in June 1989, connected with a second cousin in Saskatchewan, and worked odd jobs, including at a farm and a lumber mill. In 1990, he entered Queen's University in Kingston, Ontario. Two years later, he transferred to the University of Pennsylvania, where he studied until 1995. Although Musk has said that he earned his degrees in 1995, the University of Pennsylvania did not award them until 1997 – a Bachelor of Arts in physics and a Bachelor of Science in economics from the university's Wharton School. He reportedly hosted large, ticketed house parties to help pay for tuition, and wrote a business plan for an electronic book-scanning service similar to Google Books. In 1994, Musk held two internships in Silicon Valley: one at energy storage startup Pinnacle Research Institute, which investigated electrolytic supercapacitors for energy storage, and another at Palo Alto–based startup Rocket Science Games. In 1995, he was accepted to a graduate program in materials science at Stanford University, but did not enroll. Musk decided to join the Internet boom of the 1990s, applying for a job at Netscape, to which he reportedly never received a response. The Washington Post reported that Musk lacked legal authorization to remain and work in the United States after failing to enroll at Stanford. In response, Musk said he was allowed to work at that time and that his student visa transitioned to an H1-B. According to numerous former business associates and shareholders, Musk said he was on a student visa at the time. Business career In 1995, Musk, his brother Kimbal, and Greg Kouri founded the web software company Zip2 with funding from a group of angel investors. They housed the venture at a small rented office in Palo Alto. Replying to Rolling Stone, Musk denounced the notion that they started their company with funds borrowed from Errol Musk, but in a tweet, he recognized that his father contributed 10% of a later funding round. The company developed and marketed an Internet city guide for the newspaper publishing industry, with maps, directions, and yellow pages. According to Musk, "The website was up during the day and I was coding it at night, seven days a week, all the time." To impress investors, Musk built a large plastic structure around a standard computer to create the impression that Zip2 was powered by a small supercomputer. The Musk brothers obtained contracts with The New York Times and the Chicago Tribune, and persuaded the board of directors to abandon plans for a merger with CitySearch. Musk's attempts to become CEO were thwarted by the board. Compaq acquired Zip2 for $307 million in cash in February 1999 (equivalent to $590,000,000 in 2025), and Musk received $22 million (equivalent to $43,000,000 in 2025) for his 7-percent share. In 1999, Musk co-founded X.com, an online financial services and e-mail payment company. The startup was one of the first federally insured online banks, and, in its initial months of operation, over 200,000 customers joined the service. The company's investors regarded Musk as inexperienced and replaced him with Intuit CEO Bill Harris by the end of the year. The following year, X.com merged with online bank Confinity to avoid competition. Founded by Max Levchin and Peter Thiel, Confinity had its own money-transfer service, PayPal, which was more popular than X.com's service. Within the merged company, Musk returned as CEO. Musk's preference for Microsoft software over Unix created a rift in the company and caused Thiel to resign. Due to resulting technological issues and lack of a cohesive business model, the board ousted Musk and replaced him with Thiel in 2000.[b] Under Thiel, the company focused on the PayPal service and was renamed PayPal in 2001. In 2002, PayPal was acquired by eBay for $1.5 billion (equivalent to $2,700,000,000 in 2025) in stock, of which Musk—the largest shareholder with 11.72% of shares—received $175.8 million (equivalent to $320,000,000 in 2025). In 2017, Musk purchased the domain X.com from PayPal for an undisclosed amount, stating that it had sentimental value. In 2001, Musk became involved with the nonprofit Mars Society and discussed funding plans to place a growth-chamber for plants on Mars. Seeking a way to launch the greenhouse payloads into space, Musk made two unsuccessful trips to Moscow to purchase intercontinental ballistic missiles (ICBMs) from Russian companies NPO Lavochkin and Kosmotras. Musk instead decided to start a company to build affordable rockets. With $100 million of his early fortune, (equivalent to $180,000,000 in 2025) Musk founded SpaceX in May 2002 and became the company's CEO and Chief Engineer. SpaceX attempted its first launch of the Falcon 1 rocket in 2006. Although the rocket failed to reach Earth orbit, it was awarded a Commercial Orbital Transportation Services program contract from NASA, then led by Mike Griffin. After two more failed attempts that nearly caused Musk to go bankrupt, SpaceX succeeded in launching the Falcon 1 into orbit in 2008. Later that year, SpaceX received a $1.6 billion NASA contract (equivalent to $2,400,000,000 in 2025) for Falcon 9-launched Dragon spacecraft flights to the International Space Station (ISS), replacing the Space Shuttle after its 2011 retirement. In 2012, the Dragon vehicle docked with the ISS, a first for a commercial spacecraft. Working towards its goal of reusable rockets, in 2015 SpaceX successfully landed the first stage of a Falcon 9 on a land platform. Later landings were achieved on autonomous spaceport drone ships, an ocean-based recovery platform. In 2018, SpaceX launched the Falcon Heavy; the inaugural mission carried Musk's personal Tesla Roadster as a dummy payload. Since 2019, SpaceX has been developing Starship, a reusable, super heavy-lift launch vehicle intended to replace the Falcon 9 and Falcon Heavy. In 2020, SpaceX launched its first crewed flight, the Demo-2, becoming the first private company to place astronauts into orbit and dock a crewed spacecraft with the ISS. In 2024, NASA awarded SpaceX an $843 million (equivalent to $865,000,000 in 2025) contract to build a spacecraft that NASA will use to deorbit the ISS at the end of its lifespan. In 2015, SpaceX began development of the Starlink constellation of low Earth orbit satellites to provide satellite Internet access. After the launch of prototype satellites in 2018, the first large constellation was deployed in May 2019. As of May 2025[update], over 7,600 Starlink satellites are operational, comprising 65% of all operational Earth satellites. The total cost of the decade-long project to design, build, and deploy the constellation was estimated by SpaceX in 2020 to be $10 billion (equivalent to $12,000,000,000 in 2025).[c] During the Russian invasion of Ukraine, Musk provided free Starlink service to Ukraine, permitting Internet access and communication at a yearly cost to SpaceX of $400 million (equivalent to $440,000,000 in 2025). However, Musk refused to block Russian state media on Starlink. In 2023, Musk denied Ukraine's request to activate Starlink over Crimea to aid an attack against the Russian navy, citing fears of a nuclear response. Tesla, Inc., originally Tesla Motors, was incorporated in July 2003 by Martin Eberhard and Marc Tarpenning. Both men played active roles in the company's early development prior to Musk's involvement. Musk led the Series A round of investment in February 2004; he invested $6.35 million (equivalent to $11,000,000 in 2025), became the majority shareholder, and joined Tesla's board of directors as chairman. Musk took an active role within the company and oversaw Roadster product design, but was not deeply involved in day-to-day business operations. Following a series of escalating conflicts in 2007 and the 2008 financial crisis, Eberhard was ousted from the firm.[page needed] Musk assumed leadership of the company as CEO and product architect in 2008. A 2009 lawsuit settlement with Eberhard designated Musk as a Tesla co-founder, along with Tarpenning and two others. Tesla began delivery of the Roadster, an electric sports car, in 2008. With sales of about 2,500 vehicles, it was the first mass production all-electric car to use lithium-ion battery cells. Under Musk, Tesla has since launched several well-selling electric vehicles, including the four-door sedan Model S (2012), the crossover Model X (2015), the mass-market sedan Model 3 (2017), the crossover Model Y (2020), and the pickup truck Cybertruck (2023). In May 2020, Musk resigned as chairman of the board as part of the settlement of a lawsuit from the SEC over him tweeting that funding had been "secured" for potentially taking Tesla private. The company has also constructed multiple lithium-ion battery and electric vehicle factories, called Gigafactories. Since its initial public offering in 2010, Tesla stock has risen significantly; it became the most valuable carmaker in summer 2020, and it entered the S&P 500 later that year. In October 2021, it reached a market capitalization of $1 trillion (equivalent to $1,200,000,000,000 in 2025), the sixth company in U.S. history to do so. Musk provided the initial concept and financial capital for SolarCity, which his cousins Lyndon and Peter Rive founded in 2006. By 2013, SolarCity was the second largest provider of solar power systems in the United States. In 2014, Musk promoted the idea of SolarCity building an advanced production facility in Buffalo, New York, triple the size of the largest solar plant in the United States. Construction of the factory started in 2014 and was completed in 2017. It operated as a joint venture with Panasonic until early 2020. Tesla acquired SolarCity for $2 billion in 2016 (equivalent to $2,700,000,000 in 2025) and merged it with its battery unit to create Tesla Energy. The deal's announcement resulted in a more than 10% drop in Tesla's stock price; at the time, SolarCity was facing liquidity issues. Multiple shareholder groups filed a lawsuit against Musk and Tesla's directors, stating that the purchase of SolarCity was done solely to benefit Musk and came at the expense of Tesla and its shareholders. Tesla directors settled the lawsuit in January 2020, leaving Musk the sole remaining defendant. Two years later, the court ruled in Musk's favor. In 2016, Musk co-founded Neuralink, a neurotechnology startup, with an investment of $100 million. Neuralink aims to integrate the human brain with artificial intelligence (AI) by creating devices that are embedded in the brain. Such technology could enhance memory or allow the devices to communicate with software. The company also hopes to develop devices to treat neurological conditions like spinal cord injuries. In 2022, Neuralink announced that clinical trials would begin by the end of the year. In September 2023, the Food and Drug Administration approved Neuralink to initiate six-year human trials. Neuralink has conducted animal testing on macaques at the University of California, Davis. In 2021, the company released a video in which a macaque played the video game Pong via a Neuralink implant. The company's animal trials—which have caused the deaths of some monkeys—have led to claims of animal cruelty. The Physicians Committee for Responsible Medicine has alleged that Neuralink violated the Animal Welfare Act. Employees have complained that pressure from Musk to accelerate development has led to botched experiments and unnecessary animal deaths. In 2022, a federal probe was launched into possible animal welfare violations by Neuralink.[needs update] In 2017, Musk founded the Boring Company to construct tunnels; he also revealed plans for specialized, underground, high-occupancy vehicles that could travel up to 150 miles per hour (240 km/h) and thus circumvent above-ground traffic in major cities. Early in 2017, the company began discussions with regulatory bodies and initiated construction of a 30-foot (9.1 m) wide, 50-foot (15 m) long, and 15-foot (4.6 m) deep "test trench" on the premises of SpaceX's offices, as that required no permits. The Los Angeles tunnel, less than two miles (3.2 km) in length, debuted to journalists in 2018. It used Tesla Model Xs and was reported to be a rough ride while traveling at suboptimal speeds. Two tunnel projects announced in 2018, in Chicago and West Los Angeles, have been canceled. A tunnel beneath the Las Vegas Convention Center was completed in early 2021. Local officials have approved further expansions of the tunnel system. April 14, 2022 In early 2017, Musk expressed interest in buying Twitter and had questioned the platform's commitment to freedom of speech. By 2022, Musk had reached 9.2% stake in the company, making him the largest shareholder.[d] Musk later agreed to a deal that would appoint him to Twitter's board of directors and prohibit him from acquiring more than 14.9% of the company. Days later, Musk made a $43 billion offer to buy Twitter. By the end of April Musk had successfully concluded his bid for approximately $44 billion. This included approximately $12.5 billion in loans and $21 billion in equity financing. Having backtracked on his initial decision, Musk bought the company on October 27, 2022. Immediately after the acquisition, Musk fired several top Twitter executives including CEO Parag Agrawal; Musk became the CEO instead. Under Elon Musk, Twitter instituted monthly subscriptions for a "blue check", and laid off a significant portion of the company's staff. Musk lessened content moderation and hate speech also increased on the platform after his takeover. In late 2022, Musk released internal documents relating to Twitter's moderation of Hunter Biden's laptop controversy in the lead-up to the 2020 presidential election. Musk also promised to step down as CEO after a Twitter poll, and five months later, Musk stepped down as CEO and transitioned his role to executive chairman and chief technology officer (CTO). Despite Musk stepping down as CEO, X continues to struggle with challenges such as viral misinformation, hate speech, and antisemitism controversies. Musk has been accused of trying to silence some of his critics such as Twitch streamer Asmongold, who criticized him during one of his streams. Musk has been accused of removing their accounts' blue checkmarks, which hinders visibility and is considered a form of shadow banning, or suspending their accounts without justification. Other activities In August 2013, Musk announced plans for a version of a vactrain, and assigned engineers from SpaceX and Tesla to design a transport system between Greater Los Angeles and the San Francisco Bay Area, at an estimated cost of $6 billion. Later that year, Musk unveiled the concept, dubbed the Hyperloop, intended to make travel cheaper than any other mode of transport for such long distances. In December 2015, Musk co-founded OpenAI, a not-for-profit artificial intelligence (AI) research company aiming to develop artificial general intelligence, intended to be safe and beneficial to humanity. Musk pledged $1 billion of funding to the company, and initially gave $50 million. In 2018, Musk left the OpenAI board. Since 2018, OpenAI has made significant advances in machine learning. In July 2023, Musk launched the artificial intelligence company xAI, which aims to develop a generative AI program that competes with existing offerings like OpenAI's ChatGPT. Musk obtained funding from investors in SpaceX and Tesla, and xAI hired engineers from Google and OpenAI. December 16, 2022 Musk uses a private jet owned by Falcon Landing LLC, a SpaceX-linked company, and acquired a second jet in August 2020. His heavy use of the jets and the consequent fossil fuel usage have received criticism. Musk's flight usage is tracked on social media through ElonJet. In December 2022, Musk banned the ElonJet account on Twitter, and made temporary bans on the accounts of journalists that posted stories regarding the incident, including Donie O'Sullivan, Keith Olbermann, and journalists from The New York Times, The Washington Post, CNN, and The Intercept. In October 2025, Musk's company xAI launched Grokipedia, an AI-generated online encyclopedia that he promoted as an alternative to Wikipedia. Articles on Grokipedia are generated and reviewed by xAI's Grok chatbot. Media coverage and academic analysis described Grokipedia as frequently reusing Wikipedia content but framing contested political and social topics in line with Musk's own views and right-wing narratives. A study by Cornell University researchers and NBC News stated that Grokipedia cites sources that are blacklisted or considered "generally unreliable" on Wikipedia, for example, the conspiracy site Infowars and the neo-Nazi forum Stormfront. Wired, The Guardian and Time criticized Grokipedia for factual errors and for presenting Musk himself in unusually positive terms while downplaying controversies. Politics Musk is an outlier among business leaders who typically avoid partisan political advocacy. Musk was a registered independent voter when he lived in California. Historically, he has donated to both Democrats and Republicans, many of whom serve in states in which he has a vested interest. Since 2022, his political contributions have mostly supported Republicans, with his first vote for a Republican going to Mayra Flores in the 2022 Texas's 34th congressional district special election. In 2024, he started supporting international far-right political parties, activists, and causes, and has shared misinformation and numerous conspiracy theories. Since 2024, his views have been generally described as right-wing. Musk supported Barack Obama in 2008 and 2012, Hillary Clinton in 2016, Joe Biden in 2020, and Donald Trump in 2024. In the 2020 Democratic Party presidential primaries, Musk endorsed candidate Andrew Yang and expressed support for Yang's proposed universal basic income, and endorsed Kanye West's 2020 presidential campaign. In 2021, Musk publicly expressed opposition to the Build Back Better Act, a $3.5 trillion legislative package endorsed by Joe Biden that ultimately failed to pass due to unanimous opposition from congressional Republicans and several Democrats. In 2022, gave over $50 million to Citizens for Sanity, a conservative political action committee. In 2023, he supported Republican Ron DeSantis for the 2024 U.S. presidential election, giving $10 million to his campaign, and hosted DeSantis's campaign announcement on a Twitter Spaces event. From June 2023 to January 2024, Musk hosted a bipartisan set of X Spaces with Republican and Democratic candidates, including Robert F. Kennedy Jr., Vivek Ramaswamy, and Dean Phillips. In October 2025, former vice-president Kamala Harris commented that it was a mistake from the Democratic side to not invite Musk to a White House electric vehicle event organized in August 2021 and featuring executives from General Motors, Ford and Stellantis, despite Tesla being "the major American manufacturer of extraordinary innovation in this space." Fortune remarked that this was a nod to United Auto Workers and organized labor. Harris said presidents should put aside political loyalties when it came to recognizing innovation, and guessed that the non-invitation impacted Musk's perspective. Fortune noted that, at the time, Musk said, "Yeah, seems odd that Tesla wasn't invited." A month later, he criticized Biden as "not the friendliest administration." Jacob Silverman, author of the book Gilded Rage: Elon Musk and the Radicalization of Silicon Valley, said that the tech industry represented by Musk, Thiel, Andreessen and other capitalists, actually flourished under Biden, but the tech leaders chose Trump for their common ground on cultural issues. By early 2024, Musk had become a vocal and financial supporter of Donald Trump. In July 2024, minutes after the attempted assassination of Donald Trump, Musk endorsed him for president saying; "I fully endorse President Trump and hope for his rapid recovery." During the presidential campaign, Musk joined Trump on stage at a campaign rally, and during the campaign promoted conspiracy theories and falsehoods about Democrats, election fraud and immigration, in support of Trump. Musk was the largest individual donor of the 2024 election. In 2025, Musk contributed $19 million to the Wisconsin Supreme Court race, hoping to influence the state's future redistricting efforts and its regulations governing car manufacturers and dealers. In 2023, Musk said he shunned the World Economic Forum because it was boring. The organization commented that they had not invited him since 2015. He has participated in Dialog, dubbed "Tech Bilderberg" and organized by Peter Thiel and Auren Hoffman, though. Musk's international political actions and comments have come under increasing scrutiny and criticism, especially from the governments and leaders of France, Germany, Norway, Spain and the United Kingdom, particularly due to his position in the U.S. government as well as ownership of X. An NBC News analysis found he had boosted far-right political movements to cut immigration and curtail regulation of business in at least 18 countries on six continents since 2023. During his speech after the second inauguration of Donald Trump, Musk twice made a gesture interpreted by many as a Nazi or a fascist Roman salute.[e] He thumped his right hand over his heart, fingers spread wide, and then extended his right arm out, emphatically, at an upward angle, palm down and fingers together. He then repeated the gesture to the crowd behind him. As he finished the gestures, he said to the crowd, "My heart goes out to you. It is thanks to you that the future of civilization is assured." It was widely condemned as an intentional Nazi salute in Germany, where making such gestures is illegal. The Anti-Defamation League said it was not a Nazi salute, but other Jewish organizations disagreed and condemned the salute. American public opinion was divided on partisan lines as to whether it was a fascist salute. Musk dismissed the accusations of Nazi sympathies, deriding them as "dirty tricks" and a "tired" attack. Neo-Nazi and white supremacist groups celebrated it as a Nazi salute. Multiple European political parties demanded that Musk be banned from entering their countries. The concept of DOGE emerged in a discussion between Musk and Donald Trump, and in August 2024, Trump committed to giving Musk an advisory role, with Musk accepting the offer. In November and December 2024, Musk suggested that the organization could help to cut the U.S. federal budget, consolidate the number of federal agencies, and eliminate the Consumer Financial Protection Bureau, and that its final stage would be "deleting itself". In January 2025, the organization was created by executive order, and Musk was designated a "special government employee". Musk led the organization and was a senior advisor to the president, although his official role is not clear. In sworn statement during a lawsuit, the director of the White House Office of Administration stated that Musk "is not an employee of the U.S. DOGE Service or U.S. DOGE Service Temporary Organization", "is not the U.S. DOGE Service administrator", and has "no actual or formal authority to make government decisions himself". Trump said two days later that he had put Musk in charge of DOGE. A federal judge has ruled that Musk acted as the de facto leader of DOGE. Musk's role in the second Trump administration, particularly in response to DOGE, has attracted public backlash. He was criticized for his treatment of federal government employees, including his influence over the mass layoffs of the federal workforce. He has prioritized secrecy within the organization and has accused others of violating privacy laws. A Senate report alleged that Musk could avoid up to $2 billion in legal liability as a result of DOGE's actions. In May 2025, Bill Gates accused Musk of "killing the world's poorest children" through his cuts to USAID, which modeling by Boston University estimated had resulted in 300,000 deaths by this time, most of them of children. By November 2025, the estimated death toll had increased to 400,000 children and 200,000 adults. Musk announced on May 28, 2025, that he would depart from the Trump administration as planned when the special government employee's 130 day deadline expired, with a White House official confirming that Musk's offboarding from the Trump administration was already underway. His departure was officially confirmed during a joint Oval Office press conference with Trump on May 30, 2025. @realDonaldTrump is in the Epstein files. That is the real reason they have not been made public. June 5, 2025 After leaving office, Musk criticized the Trump administration's Big Beautiful Bill, calling it a "disgusting abomination" due to its provisions increasing the deficit. A feud began between Musk and Trump, with its most notable event being Musk alleging Trump had ties to sex offender Jeffrey Epstein on X (formerly Twitter) on June 5, 2025. Trump responded on Truth Social stating that Musk went "CRAZY" after the "EV Mandate" was purportedly taken away and threatened to cut Musk's government contracts. Musk then called for a third Trump impeachment. The next day, Trump stated that he did not wish to reconcile with Musk, and added that Musk would face "very serious consequences" if he funds Democratic candidates. On June 11, Musk publicly apologized for the tweets against Trump, saying they "went too far". Views November 6, 2022 Rejecting the conservative label, Musk has described himself as a political moderate, even as his views have become more right-wing over time. His views have been characterized as libertarian and far-right, and after his involvement in European politics, they have received criticism from world leaders such as Emmanuel Macron and Olaf Scholz. Within the context of American politics, Musk supported Democratic candidates up until 2022, at which point he voted for a Republican for the first time. He has stated support for universal basic income, gun rights, freedom of speech, a tax on carbon emissions, and H-1B visas. Musk has expressed concern about issues such as artificial intelligence (AI) and climate change, and has been a critic of wealth tax, short-selling, and government subsidies. An immigrant himself, Musk has been accused of being anti-immigration, and regularly blames immigration policies for illegal immigration. He is also a pronatalist who believes population decline is the biggest threat to civilization, and identifies as a cultural Christian. Musk has long been an advocate for space colonization, especially the colonization of Mars. He has repeatedly pushed for humanity colonizing Mars, in order to become an interplanetary species and lower the risks of human extinction. Musk has promoted conspiracy theories and made controversial statements that have led to accusations of racism, sexism, antisemitism, transphobia, disseminating disinformation, and support of white pride. While describing himself as a "pro-Semite", his comments regarding George Soros and Jewish communities have been condemned by the Anti-Defamation League and the Biden White House. Musk was criticized during the COVID-19 pandemic for making unfounded epidemiological claims, defying COVID-19 lockdowns restrictions, and supporting the Canada convoy protest against vaccine mandates. He has amplified false claims of white genocide in South Africa. Musk has been critical of Israel's actions in the Gaza Strip during the Gaza war, praised China's economic and climate goals, suggested that Taiwan and China should resolve cross-strait relations, and was described as having a close relationship with the Chinese government. In Europe, Musk expressed support for Ukraine in 2022 during the Russian invasion, recommended referendums and peace deals on the annexed Russia-occupied territories, and supported the far-right Alternative for Germany political party in 2024. Regarding British politics, Musk blamed the 2024 UK riots on mass migration and open borders, criticized Prime Minister Keir Starmer for what he described as a "two-tier" policing system, and was subsequently attacked as being responsible for spreading misinformation and amplifying the far-right. He has also voiced his support for far-right activist Tommy Robinson and pledged electoral support for Reform UK. In February 2026, Musk described Spanish Prime Minister Pedro Sánchez as a "tyrant" following Sánchez's proposal to prohibit minors under the age of 16 from accessing social media platforms. Legal affairs In 2018, Musk was sued by the U.S. Securities and Exchange Commission (SEC) for a tweet stating that funding had been secured for potentially taking Tesla private.[f] The securities fraud lawsuit characterized the tweet as false, misleading, and damaging to investors, and sought to bar Musk from serving as CEO of publicly traded companies. Two days later, Musk settled with the SEC, without admitting or denying the SEC's allegations. As a result, Musk and Tesla were fined $20 million each, and Musk was forced to step down for three years as Tesla chairman but was able to remain as CEO. Shareholders filed a lawsuit over the tweet, and in February 2023, a jury found Musk and Tesla not liable. Musk has stated in interviews that he does not regret posting the tweet that triggered the SEC investigation. In 2019, Musk stated in a tweet that Tesla would build half a million cars that year. The SEC reacted by asking a court to hold him in contempt for violating the terms of the 2018 settlement agreement. A joint agreement between Musk and the SEC eventually clarified the previous agreement details, including a list of topics about which Musk needed preclearance. In 2020, a judge blocked a lawsuit that claimed a tweet by Musk regarding Tesla stock price ("too high imo") violated the agreement. Freedom of Information Act (FOIA)-released records showed that the SEC concluded Musk had subsequently violated the agreement twice by tweeting regarding "Tesla's solar roof production volumes and its stock price". In October 2023, the SEC sued Musk over his refusal to testify a third time in an investigation into whether he violated federal law by purchasing Twitter stock in 2022. In February 2024, Judge Laurel Beeler ruled that Musk must testify again. In January 2025, the SEC filed a lawsuit against Musk for securities violations related to his purchase of Twitter. In January 2024, Delaware judge Kathaleen McCormick ruled in a 2018 lawsuit that Musk's $55 billion pay package from Tesla be rescinded. McCormick called the compensation granted by the company's board "an unfathomable sum" that was unfair to shareholders. The Delaware Supreme Court overturned McCormick's decision in December 2025, restoring Musk's compensation package and awarding $1 in nominal damages. Personal life Musk became a U.S. citizen in 2002. From the early 2000s until late 2020, Musk resided in California, where both Tesla and SpaceX were founded. He then relocated to Cameron County, Texas, saying that California had become "complacent" about its economic success. While hosting Saturday Night Live in 2021, Musk stated that he has Asperger syndrome (an outdated term for autism spectrum disorder). When asked about his experience growing up with Asperger's syndrome in a TED2022 conference in Vancouver, Musk stated that "the social cues were not intuitive ... I would just tend to take things very literally ... but then that turned out to be wrong — [people were not] simply saying exactly what they mean, there's all sorts of other things that are meant, and [it] took me a while to figure that out." Musk suffers from back pain and has undergone several spine-related surgeries, including a disc replacement. In 2000, he contracted a severe case of malaria while on vacation in South Africa. Musk has stated he uses doctor-prescribed ketamine for occasional depression and that he doses "a small amount once every other week or something like that"; since January 2024, some media outlets have reported that he takes ketamine, marijuana, LSD, ecstasy, mushrooms, cocaine and other drugs. Musk at first refused to comment on his alleged drug use, before responding that he had not tested positive for drugs, and that if drugs somehow improved his productivity, "I would definitely take them!". The New York Times' investigations revealed Musk's overuse of ketamine and numerous other drugs, as well as strained family relationships and concerns from close associates who have become troubled by his public behavior as he became more involved in political activities and government work. According to The Washington Post, President Trump described Musk as "a big-time drug addict". Through his own label Emo G Records, Musk released a rap track, "RIP Harambe", on SoundCloud in March 2019. The following year, he released an EDM track, "Don't Doubt Ur Vibe", featuring his own lyrics and vocals. Musk plays video games, which he stated has a "'restoring effect' that helps his 'mental calibration'". Some games he plays include Quake, Diablo IV, Elden Ring, and Polytopia. Musk once claimed to be one of the world's top video game players but has since admitted to "account boosting", or cheating by hiring outside services to achieve top player rankings. Musk has justified the boosting by claiming that all top accounts do it so he has to as well to remain competitive. In 2024 and 2025, Musk criticized the video game Assassin's Creed Shadows and its creator Ubisoft for "woke" content. Musk posted to X that "DEI kills art" and specified the inclusion of the historical figure Yasuke in the Assassin's Creed game as offensive; he also called the game "terrible". Ubisoft responded by saying that Musk's comments were "just feeding hatred" and that they were focused on producing a game not pushing politics. Musk has fathered at least 14 children, one of whom died as an infant. The Wall Street Journal reported in 2025 that sources close to Musk suggest that the "true number of Musk's children is much higher than publicly known". He had six children with his first wife, Canadian author Justine Wilson, whom he met while attending Queen's University in Ontario, Canada; they married in 2000. In 2002, their first child Nevada Musk died of sudden infant death syndrome at the age of 10 weeks. After his death, the couple used in vitro fertilization (IVF) to continue their family; they had twins in 2004, followed by triplets in 2006. The couple divorced in 2008 and have shared custody of their children. The elder twin he had with Wilson came out as a trans woman and, in 2022, officially changed her name to Vivian Jenna Wilson, adopting her mother's surname because she no longer wished to be associated with Musk. Musk began dating English actress Talulah Riley in 2008. They married two years later at Dornoch Cathedral in Scotland. In 2012, the couple divorced, then remarried the following year. After briefly filing for divorce in 2014, Musk finalized a second divorce from Riley in 2016. Musk then dated the American actress Amber Heard for several months in 2017; he had reportedly been "pursuing" her since 2012. In 2018, Musk and Canadian musician Grimes confirmed they were dating. Grimes and Musk have three children, born in 2020, 2021, and 2022.[g] Musk and Grimes originally gave their eldest child the name "X Æ A-12", which would have violated California regulations as it contained characters that are not in the modern English alphabet; the names registered on the birth certificate are "X" as a first name, "Æ A-Xii" as a middle name, and "Musk" as a last name. They received criticism for choosing a name perceived to be impractical and difficult to pronounce; Musk has said the intended pronunciation is "X Ash A Twelve". Their second child was born via surrogacy. Despite the pregnancy, Musk confirmed reports that the couple were "semi-separated" in September 2021; in an interview with Time in December 2021, he said he was single. In October 2023, Grimes sued Musk over parental rights and custody of X Æ A-Xii. Elon Musk has taken X Æ A-Xii to multiple official events in Washington, D.C. during Trump's second term in office. Also in July 2022, The Wall Street Journal reported that Musk allegedly had an affair with Nicole Shanahan, the wife of Google co-founder Sergey Brin, in 2021, leading to their divorce the following year. Musk denied the report. Musk also had a relationship with Australian actress Natasha Bassett, who has been described as "an occasional girlfriend". In October 2024, The New York Times reported Musk bought a Texas compound for his children and their mothers, though Musk denied having done so. Musk also has four children with Shivon Zilis, director of operations and special projects at Neuralink: twins born via IVF in 2021, a child born in 2024 via surrogacy and a child born in 2025.[h] On February 14, 2025, Ashley St. Clair, an influencer and author, posted on X claiming to have given birth to Musk's son Romulus five months earlier, which media outlets reported as Musk's supposed thirteenth child.[i] On February 22, 2025, it was reported that St Clair had filed for sole custody of her five-month-old son and for Musk to be recognised as the child's father. On March 31, 2025, Musk wrote that, while he was unsure if he was the father of St. Clair's child, he had paid St. Clair $2.5 million and would continue paying her $500,000 per year.[j] Later reporting from the Wall Street Journal indicated that $1 million of these payments to St. Clair were structured as a loan. In 2014, Musk and Ghislaine Maxwell appeared together in a photograph taken at an Academy Awards after-party, which Musk later described as a "photobomb". The January 2026 Epstein files contain emails between Musk and Epstein from 2012 to 2013, after Epstein's first conviction. Emails released on January 30, 2026, indicated that Epstein invited Musk to visit his private island on multiple occasions. The correspondence showed that while Epstein repeatedly encouraged Musk to attend, Musk did not visit the island. In one instance, Musk discussed the possibility of attending a party with his then-wife Talulah Riley and asked which day would be the "wildest party"; according to the emails, the visit did not take place after Epstein later cancelled the plans.[k] On Christmas day in 2012, Musk emailed Epstein asking "Do you have any parties planned? I’ve been working to the edge of sanity this year and so, once my kids head home after Christmas, I really want to hit the party scene in St Barts or elsewhere and let loose. The invitation is much appreciated, but a peaceful island experience is the opposite of what I’m looking for". Epstein replied that the "ratio on my island" might make Musk's wife uncomfortable to which Musk responded, "Ratio is not a problem for Talulah". On September 11, 2013, Epstein sent an email asking Musk if he had any plans for coming to New York for the opening of the United Nations General Assembly where many "interesting people" would be coming to his house to which Musk responded that "Flying to NY to see UN diplomats do nothing would be an unwise use of time". Epstein responded by stating "Do you think i am retarded. Just kidding, there is no one over 25 and all very cute." Musk has denied any close relationship with Epstein and described him as a "creep" who attempted to ingratiate himself with influential people. When Musk was asked in 2019 if he introduced Epstein to Mark Zuckerberg, Musk responded: "I don’t recall introducing Epstein to anyone, as I don’t know the guy well enough to do so." The released emails nonetheless showed cordial exchanges on a range of topics, including Musk's inquiry about parties on the island. The correspondence also indicated that Musk suggested hosting Epstein at SpaceX, while Epstein separately discussed plans to tour SpaceX and bring "the girls", though there is no evidence that such a visit occurred. Musk has described the release of the files a "distraction", later accusing the second Trump administration of suppressing them to protect powerful individuals, including Trump himself.[l] Wealth Elon Musk is the wealthiest person in the world, with an estimated net worth of US$690 billion as of January 2026, according to the Bloomberg Billionaires Index, and $852 billion according to Forbes, primarily from his ownership stakes in SpaceX and Tesla. Having been first listed on the Forbes Billionaires List in 2012, around 75% of Musk's wealth was derived from Tesla stock in November 2020, although he describes himself as "cash poor". According to Forbes, he became the first person in the world to achieve a net worth of $300 billion in 2021; $400 billion in December 2024; $500 billion in October 2025; $600 billion in mid-December 2025; $700 billion later that month; and $800 billion in February 2026. In November 2025, a Tesla pay package worth potentially $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Public image Although his ventures have been highly influential within their separate industries starting in the 2000s, Musk only became a public figure in the early 2010s. He has been described as an eccentric who makes spontaneous and impactful decisions, while also often making controversial statements, contrary to other billionaires who prefer reclusiveness to protect their businesses. Musk's actions and his expressed views have made him a polarizing figure. Biographer Ashlee Vance described people's opinions of Musk as polarized due to his "part philosopher, part troll" persona on Twitter. He has drawn denouncement for using his platform to mock the self-selection of personal pronouns, while also receiving praise for bringing international attention to matters like British survivors of grooming gangs. Musk has been described as an American oligarch due to his extensive influence over public discourse, social media, industry, politics, and government policy. After Trump's re-election, Musk's influence and actions during the transition period and the second presidency of Donald Trump led some to call him "President Musk", the "actual president-elect", "shadow president" or "co-president". Awards for his contributions to the development of the Falcon rockets include the American Institute of Aeronautics and Astronautics George Low Transportation Award in 2008, the Fédération Aéronautique Internationale Gold Space Medal in 2010, and the Royal Aeronautical Society Gold Medal in 2012. In 2015, he received an honorary doctorate in engineering and technology from Yale University and an Institute of Electrical and Electronics Engineers Honorary Membership. Musk was elected a Fellow of the Royal Society (FRS) in 2018.[m] In 2022, Musk was elected to the National Academy of Engineering. Time has listed Musk as one of the most influential people in the world in 2010, 2013, 2018, and 2021. Musk was selected as Time's "Person of the Year" for 2021. Then Time editor-in-chief Edward Felsenthal wrote that, "Person of the Year is a marker of influence, and few individuals have had more influence than Musk on life on Earth, and potentially life off Earth too." Notes References Works cited Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Mars#cite_note-Giuranna-221] | [TOKENS: 11899] |
Contents Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", for its orange-red appearance. Mars is a desert-like rocky planet with a tenuous atmosphere that is primarily carbon dioxide (CO2). At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from −153 to 20 °C (−243 to 68 °F), and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, fog, frost, larger polar regions of permafrost and ice caps (with seasonal CO2 snow), but no bodies of liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. Its diameter, 6,779 km (4,212 mi), is about half the Earth's, or twice the Moon's, and its surface area is the size of all the dry land of Earth. Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south divide, the Martian dichotomy, with the northern hemisphere mainly consisting of relatively flat, low lying plains, and the southern hemisphere of cratered highlands. Geologically, the planet is fairly active with marsquakes trembling underneath the ground, but also hosts many enormous volcanoes that are extinct (the tallest is Olympus Mons, 21.9 km or 13.6 mi tall), as well as one of the largest canyons in the Solar System (Valles Marineris, 4,000 km or 2,500 mi long). Mars has two natural satellites that are small and irregular in shape: Phobos and Deimos. With a significant axial tilt of 25 degrees, Mars experiences seasons, like Earth (which has an axial tilt of 23.5 degrees). A Martian solar year is equal to 1.88 Earth years (687 Earth days), a Martian solar day (sol) is equal to 24.6 hours. Mars formed along with the other planets approximately 4.5 billion years ago. During the martian Noachian period (4.5 to 3.5 billion years ago), its surface was marked by meteor impacts, valley formation, erosion, the possible presence of water oceans and the loss of its magnetosphere. The Hesperian period (beginning 3.5 billion years ago and ending 3.3–2.9 billion years ago) was dominated by widespread volcanic activity and flooding that carved immense outflow channels. The Amazonian period, which continues to the present, is the currently dominating and remaining influence on geological processes. Because of Mars's geological history, the possibility of past or present life on Mars remains an area of active scientific investigation, with some possible traces needing further examination. Being visible with the naked eye in Earth's sky as a red wandering star, Mars has been observed throughout history, acquiring diverse associations in different cultures. In 1963 the first flight to Mars took place with Mars 1, but communication was lost en route. The first successful flyby exploration of Mars was conducted in 1965 with Mariner 4. In 1971 Mariner 9 entered orbit around Mars, being the first spacecraft to orbit any body other than the Moon, Sun or Earth; following in the same year were the first uncontrolled impact (Mars 2) and first successful landing (Mars 3) on Mars. Probes have been active on Mars continuously since 1997. At times, more than ten probes have simultaneously operated in orbit or on the surface, more than at any other planet beyond Earth. Mars is an often proposed target for future crewed exploration missions, though no such mission is currently planned. Natural history Scientists have theorized that during the Solar System's formation, Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine, phosphorus, and sulfur, are much more common on Mars than on Earth; these elements were probably pushed outward by the young Sun's energetic solar wind. After the formation of the planets, the inner Solar System may have been subjected to the so-called Late Heavy Bombardment. About 60% of the surface of Mars shows a record of impacts from that era, whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. However, more recent modeling has disputed the existence of the Late Heavy Bombardment. There is evidence of an enormous impact basin in the Northern Hemisphere of Mars, spanning 10,600 by 8,500 kilometres (6,600 by 5,300 mi), or roughly four times the size of the Moon's South Pole–Aitken basin, which would be the largest impact basin yet discovered if confirmed. It has been hypothesized that the basin was formed when Mars was struck by a Pluto-sized body about four billion years ago. The event, thought to be the cause of the Martian hemispheric dichotomy, created the smooth Borealis basin that covers 40% of the planet. A 2023 study shows evidence, based on the orbital inclination of Deimos (a small moon of Mars), that Mars may once have had a ring system 3.5 billion years to 4 billion years ago. This ring system may have been formed from a moon, 20 times more massive than Phobos, orbiting Mars billions of years ago; and Phobos would be a remnant of that ring. Epochs: The geological history of Mars can be split into many periods, but the following are the three primary periods: Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200 million years ago. Water flows in the grabens called the Cerberus Fossae occurred less than 20 million years ago, indicating equally recent volcanic intrusions. The Mars Reconnaissance Orbiter has captured images of avalanches. Physical characteristics Mars is approximately half the diameter of Earth or twice that of the Moon, with a surface area only slightly less than the total area of Earth's dry land. Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity. Mars is the only presently known example of a desert planet, a rocky planet with a surface akin to that of Earth's deserts. The red-orange appearance of the Martian surface is caused by iron(III) oxide (nanophase Fe2O3) and the iron(III) oxide-hydroxide mineral goethite. It can look like butterscotch; other common surface colors include golden, brown, tan, and greenish, depending on the minerals present. Like Earth, Mars is differentiated into a dense metallic core overlaid by less dense rocky layers. The outermost layer is the crust, which is on average about 42–56 kilometres (26–35 mi) thick, with a minimum thickness of 6 kilometres (3.7 mi) in Isidis Planitia, and a maximum thickness of 117 kilometres (73 mi) in the southern Tharsis plateau. For comparison, Earth's crust averages 27.3 ± 4.8 km in thickness. The most abundant elements in the Martian crust are silicon, oxygen, iron, magnesium, aluminum, calcium, and potassium. Mars is confirmed to be seismically active; in 2019, it was reported that InSight had detected and recorded over 450 marsquakes and related events. Beneath the crust is a silicate mantle responsible for many of the tectonic and volcanic features on the planet's surface. The upper Martian mantle is a low-velocity zone, where the velocity of seismic waves is lower than surrounding depth intervals. The mantle appears to be rigid down to the depth of about 250 km, giving Mars a very thick lithosphere compared to Earth. Below this the mantle gradually becomes more ductile, and the seismic wave velocity starts to grow again. The Martian mantle does not appear to have a thermally insulating layer analogous to Earth's lower mantle; instead, below 1050 km in depth, it becomes mineralogically similar to Earth's transition zone. At the bottom of the mantle lies a basal liquid silicate layer approximately 150–180 km thick. The Martian mantle appears to be highly heterogenous, with dense fragments up to 4 km across, likely injected deep into the planet by colossal impacts ~4.5 billion years ago; high-frequency waves from eight marsquakes slowed as they passed these localized regions, and modeling indicates the heterogeneities are compositionally distinct debris preserved because Mars lacks plate tectonics and has a sluggishly convecting interior that prevents complete homogenization. Mars's iron and nickel core is at least partially molten, and may have a solid inner core. It is around half of Mars's radius, approximately 1650–1675 km, and is enriched in light elements such as sulfur, oxygen, carbon, and hydrogen. The temperature of the core is estimated to be 2000–2400 K, compared to 5400–6230 K for Earth's solid inner core. In 2025, based on data from the InSight lander, a group of researchers reported the detection of a solid inner core 613 kilometres (381 mi) ± 67 kilometres (42 mi) in radius. Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The Martian surface is primarily composed of tholeiitic basalt, although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth, or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have been found. Much of the surface is deeply covered by finely grained iron(III) oxide dust. The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in soils on Earth, and are necessary for plant growth. Experiments performed by the lander showed that the Martian soil has a basic pH of 7.7, and contains 0.6% perchlorate by weight, concentrations that are toxic to humans. Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted hypotheses include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils. Several other explanations have been put forward, including those that involve water or even the growth of organisms. Environmental radiation levels on the surface are on average 0.64 millisieverts of radiation per day, and significantly less than the radiation of 1.84 millisieverts per day or 22 millirads per day during the flight to and from Mars. For comparison the radiation levels in low Earth orbit, where Earth's space stations orbit, are around 0.5 millisieverts of radiation per day. Hellas Planitia has the lowest surface radiation at about 0.342 millisieverts per day, featuring lava tubes southwest of Hadriacus Mons with potentially levels as low as 0.064 millisieverts per day, comparable to radiation levels during flights on Earth. Although Mars has no evidence of a structured global magnetic field, observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors. One hypothesis, published in 1999 and re-examined in October 2005 (with the help of the Mars Global Surveyor), is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded. Geography and features Although better remembered for mapping the Moon, Johann Heinrich von Mädler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mädler combined ten years of observations and drew the first map of Mars. Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50 km are named for deceased scientists and writers and others who have contributed to the study of Mars. Smaller craters are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; smaller valleys are named for rivers. Large albedo features retain many of the older names but are often updated to reflect new knowledge of the nature of the features. For example, Nix Olympica (the snows of Olympus) has become Olympus Mons (Mount Olympus). The surface of Mars as seen from Earth is divided into two kinds of areas, with differing albedo. The paler plains covered with dust and sand rich in reddish iron oxides were once thought of as Martian "continents" and given names like Arabia Terra (land of Arabia) or Amazonis Planitia (Amazonian plain). The dark features were thought to be seas, hence their names Mare Erythraeum, Mare Sirenum and Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major Planum. The permanent northern polar ice cap is named Planum Boreum. The southern cap is called Planum Australe. Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft Mariner 9 provided extensive imagery of Mars in 1972, a small crater (later called Airy-0), located in the Sinus Meridiani ("Middle Bay" or "Meridian Bay"), was chosen by Merton E. Davies, Harold Masursky, and Gérard de Vaucouleurs for the definition of 0.0° longitude to coincide with the original selection. Because Mars has no oceans, and hence no "sea level", a zero-elevation surface had to be selected as a reference level; this is called the areoid of Mars, analogous to the terrestrial geoid. Zero altitude was defined by the height at which there is 610.5 Pa (6.105 mbar) of atmospheric pressure. This pressure corresponds to the triple point of water, and it is about 0.6% of the sea level surface pressure on Earth (0.006 atm). For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles, each named for a classical albedo feature it contains. In April 2023, The New York Times reported an updated global map of Mars based on images from the Hope spacecraft. A related, but much more detailed, global Mars map was released by NASA on 16 April 2023. The vast upland region Tharsis contains several massive volcanoes, which include the shield volcano Olympus Mons. The edifice is over 600 km (370 mi) wide. Because the mountain is so large, with complex structure at its edges, giving a definite height to it is difficult. Its local relief, from the foot of the cliffs which form its northwest margin to its peak, is over 21 km (13 mi), a little over twice the height of Mauna Kea as measured from its base on the ocean floor. The total elevation change from the plains of Amazonis Planitia, over 1,000 km (620 mi) to the northwest, to the summit approaches 26 km (16 mi), roughly three times the height of Mount Everest, which in comparison stands at just over 8.8 kilometres (5.5 mi). Consequently, Olympus Mons is either the tallest or second-tallest mountain in the Solar System; the only known mountain which might be taller is the Rheasilvia peak on the asteroid Vesta, at 20–25 km (12–16 mi). The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon. If this is the case, the Northern Hemisphere of Mars would be the site of an impact crater 10,600 by 8,500 kilometres (6,600 by 5,300 mi) in size, or roughly the area of Europe, Asia, and Australia combined, surpassing Utopia Planitia and the Moon's South Pole–Aitken basin as the largest impact crater in the Solar System. Mars is scarred by 43,000 impact craters with a diameter of 5 kilometres (3.1 mi) or greater. The largest exposed crater is Hellas, which is 2,300 kilometres (1,400 mi) wide and 7,000 metres (23,000 ft) deep, and is a light albedo feature clearly visible from Earth. There are other notable impact features, such as Argyre, which is around 1,800 kilometres (1,100 mi) in diameter, and Isidis, which is around 1,500 kilometres (930 mi) in diameter. Due to the smaller mass and size of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, i.e., those that lie within the orbit of Jupiter. Martian craters can[discuss] have a morphology that suggests the ground became wet after the meteor impact. The large canyon, Valles Marineris (Latin for 'Mariner Valleys, also known as Agathodaemon in the old canal maps), has a length of 4,000 kilometres (2,500 mi) and a depth of up to 7 kilometres (4.3 mi). The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only 446 kilometres (277 mi) long and nearly 2 kilometres (1.2 mi) deep. Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where 150 kilometres (93 mi) of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement. Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from 100 to 252 metres (328 to 827 ft) wide and they are estimated to be at least 73 to 96 metres (240 to 315 ft) deep. Because light does not reach the floor of most of the caves, they may extend much deeper than these lower estimates and widen below the surface. "Dena" is the only exception; its floor is visible and was measured to be 130 metres (430 ft) deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface. Martian geysers (or CO2 jets) are putative sites of small gas and dust eruptions that occur in the south polar region of Mars during the spring thaw. "Dark dune spots" and "spiders" – or araneiforms – are the two most visible types of features ascribed to these eruptions. Similarly sized dust will settle from the thinner Martian atmosphere sooner than it would on Earth. For example, the dust suspended by the 2001 global dust storms on Mars only remained in the Martian atmosphere for 0.6 years, while the dust from Mount Pinatubo took about two years to settle. However, under current Martian conditions, the mass movements involved are generally much smaller than on Earth. Even the 2001 global dust storms on Mars moved only the equivalent of a very thin dust layer – about 3 μm thick if deposited with uniform thickness between 58° north and south of the equator. Dust deposition at the two rover sites has proceeded at a rate of about the thickness of a grain every 100 sols. Atmosphere Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. Both Mars Global Surveyor and Mars Express have detected ionized atmospheric particles trailing off into space behind Mars, and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from a low of 30 Pa (0.0044 psi) on Olympus Mons to over 1,155 Pa (0.1675 psi) in Hellas Planitia, with a mean pressure at the surface level of 600 Pa (0.087 psi). The highest atmospheric density on Mars is equal to that found 35 kilometres (22 mi) above Earth's surface. The resulting mean surface pressure is only 0.6% of Earth's 101.3 kPa (14.69 psi). The scale height of the atmosphere is about 10.8 kilometres (6.7 mi), which is higher than Earth's 6 kilometres (3.7 mi), because the surface gravity of Mars is only about 38% of Earth's. The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates about 1.5 μm in diameter which give the Martian sky a tawny color when seen from the surface. It may take on a pink hue due to iron oxide particles suspended in it. Despite repeated detections of methane on Mars, there is no scientific consensus as to its origin. One suggestion is that methane exists on Mars and that its concentration fluctuates seasonally. The existence of methane could be produced by non-biological process such as serpentinization involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars, or by Martian life. Compared to Earth, its higher concentration of atmospheric CO2 and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the Perseverance rover, researchers concluded that the speed of sound there is approximately 240 m/s for frequencies below 240 Hz, and 250 m/s for those above. Auroras have been detected on Mars. Because Mars lacks a global magnetic field, the types and distribution of auroras there differ from those on Earth; rather than being mostly restricted to polar regions as is the case on Earth, a Martian aurora can encompass the planet. In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25 times brighter than any observed earlier, due to a massive, and unexpected, solar storm in the middle of the month. Mars has seasons, alternating between its northern and southern hemispheres, similar to on Earth. Additionally the orbit of Mars has, compared to Earth's, a large eccentricity and approaches perihelion when it is summer in its southern hemisphere and winter in its northern, and aphelion when it is winter in its southern hemisphere and summer in its northern. As a result, the seasons in its southern hemisphere are more extreme and the seasons in its northern are milder than would otherwise be the case. The summer temperatures in the south can be warmer than the equivalent summer temperatures in the north by up to 30 °C (54 °F). Martian surface temperatures vary from lows of about −110 °C (−166 °F) to highs of up to 35 °C (95 °F) in equatorial summer. The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure (about 1% that of the atmosphere of Earth), and the low thermal inertia of Martian soil. The planet is 1.52 times as far from the Sun as Earth, resulting in just 43% of the amount of sunlight. Mars has the largest dust storms in the Solar System, reaching speeds of over 160 km/h (100 mph). These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase global temperature. Seasons also produce dry ice covering polar ice caps. Hydrology While Mars contains water in larger amounts, most of it is dust covered water ice at the Martian polar ice caps. The volume of water ice in the south polar ice cap, if melted, would be enough to cover most of the surface of the planet with a depth of 11 metres (36 ft). Water in its liquid form cannot persist on the surface due to Mars's low atmospheric pressure, which is less than 1% that of Earth. Only at the lowest of elevations are the pressure and temperature high enough for liquid water to exist for short periods. Although little water is present in the atmosphere, there is enough to produce clouds of water ice and different cases of snow and frost, often mixed with snow of carbon dioxide dry ice. Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels, cut across the surface in about 25 places. These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers, though some of these structures have been hypothesized to result from the action of glaciers or lava. One of the larger examples, Ma'adim Vallis, is 700 kilometres (430 mi) long, much greater than the Grand Canyon, with a width of 20 kilometres (12 mi) and a depth of 2 kilometres (1.2 mi) in places. It is thought to have been carved by flowing water early in Mars's history. The youngest of these channels is thought to have formed only a few million years ago. Elsewhere, particularly on the oldest areas of the Martian surface, finer-scale, dendritic networks of valleys are spread across significant proportions of the landscape. Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history. Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks, but precipitation was probably the root cause of the incision in almost all cases. Along craters and canyon walls, there are thousands of features that appear similar to terrestrial gullies. The gullies tend to be in the highlands of the Southern Hemisphere and face the Equator; all are poleward of 30° latitude. A number of authors have suggested that their formation process involves liquid water, probably from melting ice, although others have argued for formation mechanisms involving carbon dioxide frost or the movement of dry dust. No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed, indicating that these are young features, possibly still active. Other geological features, such as deltas and alluvial fans preserved in craters, are further evidence for warmer, wetter conditions at an interval or intervals in earlier Mars history. Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface, for which there is independent mineralogical, sedimentological and geomorphological evidence. Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water. The chemical signature of water vapor on Mars was first unequivocally demonstrated in 1963 by spectroscopy using an Earth-based telescope. In 2004, Opportunity detected the mineral jarosite. This forms only in the presence of acidic water, showing that water once existed on Mars. The Spirit rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum, which also forms in the presence of water, was found on the surface by NASA's Mars rover Opportunity. It is estimated that the amount of water in the upper mantle of Mars, represented by hydroxyl ions contained within Martian minerals, is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200–1,000 metres (660–3,280 ft). On 18 March 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock. Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 centimetres (24 in), during the rover's traverse from the Bradbury Landing site to the Yellowknife Bay area in the Glenelg terrain. In September 2015, NASA announced that they had found strong evidence of hydrated brine flows in recurring slope lineae, based on spectrometer readings of the darkened areas of slopes. These streaks flow downhill in Martian summer, when the temperature is above −23 °C, and freeze at lower temperatures. These observations supported earlier hypotheses, based on timing of formation and their rate of growth, that these dark streaks resulted from water flowing just below the surface. However, later work suggested that the lineae may be dry, granular flows instead, with at most a limited role for water in initiating the process. A definitive conclusion about the presence, extent, and role of liquid water on the Martian surface remains elusive. Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial. In March 2015, scientists stated that such an ocean might have been the size of Earth's Arctic Ocean. This finding was derived from the ratio of protium to deuterium in the modern Martian atmosphere compared to that ratio on Earth. The amount of Martian deuterium (D/H = 9.3 ± 1.7 10−4) is five to seven times the amount on Earth (D/H = 1.56 10−4), suggesting that ancient Mars had significantly higher levels of water. Results from the Curiosity rover had previously found a high ratio of deuterium in Gale Crater, though not significantly high enough to suggest the former presence of an ocean. Other scientists caution that these results have not been confirmed, and point out that Martian climate models have not yet shown that the planet was warm enough in the past to support bodies of liquid water. Near the northern polar cap is the 81.4 kilometres (50.6 mi) wide Korolev Crater, which the Mars Express orbiter found to be filled with approximately 2,200 cubic kilometres (530 cu mi) of water ice. In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior (which is 12,100 cubic kilometers). During observations from 2018 through 2021, the ExoMars Trace Gas Orbiter spotted indications of water, probably subsurface ice, in the Valles Marineris canyon system. Orbital motion Mars's average distance from the Sun is roughly 230 million km (143 million mi), and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. The gravitational potential difference and thus the delta-v needed to transfer between Mars and Earth is the second lowest for Earth. The axial tilt of Mars is 25.19° relative to its orbital plane, which is similar to the axial tilt of Earth. As a result, Mars has seasons like Earth, though on Mars they are nearly twice as long because its orbital period is that much longer. In the present day, the orientation of the north pole of Mars is close to the star Deneb. Mars has a relatively pronounced orbital eccentricity of about 0.09; of the seven other planets in the Solar System, only Mercury has a larger orbital eccentricity. It is known that in the past, Mars has had a much more circular orbit. At one point, 1.35 million Earth years ago, Mars had an eccentricity of roughly 0.002, much less than that of Earth today. Mars's cycle of eccentricity is 96,000 Earth years compared to Earth's cycle of 100,000 years. Mars has its closest approach to Earth (opposition) in a synodic period of 779.94 days. It should not be confused with Mars conjunction, where the Earth and Mars are at opposite sides of the Solar System and form a straight line crossing the Sun. The average time between the successive oppositions of Mars, its synodic period, is 780 days; but the number of days between successive oppositions can range from 764 to 812. The distance at close approach varies between about 54 and 103 million km (34 and 64 million mi) due to the planets' elliptical orbits, which causes comparable variation in angular size. At their furthest Mars and Earth can be as far as 401 million km (249 million mi) apart. Mars comes into opposition from Earth every 2.1 years. The planets come into opposition near Mars's perihelion in 2003, 2018 and 2035, with the 2020 and 2033 events being particularly close to perihelic opposition. The mean apparent magnitude of Mars is +0.71 with a standard deviation of 1.05. Because the orbit of Mars is eccentric, the magnitude at opposition from the Sun can range from about −3.0 to −1.4. The minimum brightness is magnitude +1.86 when the planet is near aphelion and in conjunction with the Sun. At its brightest, Mars (along with Jupiter) is second only to Venus in apparent brightness. Mars usually appears distinctly yellow, orange, or red. When farthest away from Earth, it is more than seven times farther away than when it is closest. Mars is usually close enough for particularly good viewing once or twice at 15-year or 17-year intervals. Optical ground-based telescopes are typically limited to resolving features about 300 kilometres (190 mi) across when Earth and Mars are closest because of Earth's atmosphere. As Mars approaches opposition, it begins a period of retrograde motion, which means it will appear to move backwards in a looping curve with respect to the background stars. This retrograde motion lasts for about 72 days, and Mars reaches its peak apparent brightness in the middle of this interval. Moons Mars has two relatively small (compared to Earth's) natural moons, Phobos (about 22 km (14 mi) in diameter) and Deimos (about 12 km (7.5 mi) in diameter), which orbit at 9,376 km (5,826 mi) and 23,460 km (14,580 mi) around the planet. The origin of both moons is unclear, although a popular theory states that they were asteroids captured into Martian orbit. Both satellites were discovered in 1877 by Asaph Hall and were named after the characters Phobos (the deity of panic and fear) and Deimos (the deity of terror and dread), twins from Greek mythology who accompanied their father Ares, god of war, into battle. Mars was the Roman equivalent to Ares. In modern Greek, the planet retains its ancient name Ares (Aris: Άρης). From the surface of Mars, the motions of Phobos and Deimos appear different from that of the Earth's satellite, the Moon. Phobos rises in the west, sets in the east, and rises again in just 11 hours. Deimos, being only just outside synchronous orbit – where the orbital period would match the planet's period of rotation – rises as expected in the east, but slowly. Because the orbit of Phobos is below a synchronous altitude, tidal forces from Mars are gradually lowering its orbit. In about 50 million years, it could either crash into Mars's surface or break up into a ring structure around the planet. The origin of the two satellites is not well understood. Their low albedo and carbonaceous chondrite composition have been regarded as similar to asteroids, supporting a capture theory. The unstable orbit of Phobos would seem to point toward a relatively recent capture. But both have circular orbits near the equator, which is unusual for captured objects, and the required capture dynamics are complex. Accretion early in the history of Mars is plausible, but would not account for a composition resembling asteroids rather than Mars itself, if that is confirmed. Mars may have yet-undiscovered moons, smaller than 50 to 100 metres (160 to 330 ft) in diameter, and a dust ring is predicted to exist between Phobos and Deimos. A third possibility for their origin as satellites of Mars is the involvement of a third body or a type of impact disruption. More-recent lines of evidence for Phobos having a highly porous interior, and suggesting a composition containing mainly phyllosilicates and other minerals known from Mars, point toward an origin of Phobos from material ejected by an impact on Mars that reaccreted in Martian orbit, similar to the prevailing theory for the origin of Earth's satellite. Although the visible and near-infrared (VNIR) spectra of the moons of Mars resemble those of outer-belt asteroids, the thermal infrared spectra of Phobos are reported to be inconsistent with chondrites of any class. It is also possible that Phobos and Deimos were fragments of an older moon, formed by debris from a large impact on Mars, and then destroyed by a more recent impact upon the satellite. More recently, a study conducted by a team of researchers from multiple countries suggests that a lost moon, at least fifteen times the size of Phobos, may have existed in the past. By analyzing rocks which point to tidal processes on the planet, it is possible that these tides may have been regulated by a past moon. Human observations and exploration The history of observations of Mars is marked by oppositions of Mars when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars, which are distinguished because Mars is close to perihelion, making it even closer to Earth. The ancient Sumerians named Mars Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh. In Mesopotamian texts, Mars is referred to as the "star of judgement of the fate of the dead". The existence of Mars as a wandering object in the night sky was also recorded by the ancient Egyptian astronomers and, by 1534 BCE, they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They invented arithmetic methods for making minor corrections to the predicted positions of the planets. In Ancient Greece, the planet was known as Πυρόεις. Commonly, the Greek name for the planet now referred to as Mars, was Ares. It was the Romans who named the planet Mars, for their god of war, often represented by the sword and shield of the planet's namesake. In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating that the planet was farther away. Ptolemy, a Greek living in Alexandria, attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented in the multi-volume collection later called the Almagest (from the Arabic for "greatest"), which became the authoritative treatise on Western astronomy for the next fourteen centuries. Literature from ancient China confirms that Mars was known by Chinese astronomers by no later than the fourth century BCE. In the East Asian cultures, Mars is traditionally referred to as the "fire star" (火星) based on the Wuxing system. In 1609 Johannes Kepler published a 10 year study of Martian orbit, using the diurnal parallax of Mars, measured by Tycho Brahe, to make a preliminary calculation of the relative distance to the planet. From Brahe's observations of Mars, Kepler deduced that the planet orbited the Sun not in a circle, but in an ellipse. Moreover, Kepler showed that Mars sped up as it approached the Sun and slowed down as it moved farther away, in a manner that later physicists would explain as a consequence of the conservation of angular momentum.: 433–437 In 1610 the first use of a telescope for astronomical observation, including Mars, was performed by Italian astronomer Galileo Galilei. With the telescope the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance. This was first performed by Giovanni Domenico Cassini in 1672. The early parallax measurements were hampered by the quality of the instruments. The only occultation of Mars by Venus observed was that of 13 October 1590, seen by Michael Maestlin at Heidelberg. By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. On 5 September 1877, a perihelic opposition to Mars occurred. The Italian astronomer Giovanni Schiaparelli used a 22-centimetre (8.7 in) telescope in Milan to help produce the first detailed map of Mars. These maps notably contained features he called canali, which, with the possible exception of the natural canyon Valles Marineris, were later shown to be an optical illusion. These canali were supposedly long, straight lines on the surface of Mars, to which he gave names of famous rivers on Earth. His term, which means "channels" or "grooves", was popularly mistranslated in English as "canals". Influenced by the observations, the orientalist Percival Lowell founded an observatory which had 30- and 45-centimetre (12- and 18-in) telescopes. The observatory was used for the exploration of Mars during the last good opportunity in 1894, and the following less favorable oppositions. He published several books on Mars and life on the planet, which had a great influence on the public. The canali were independently observed by other astronomers, like Henri Joseph Perrotin and Louis Thollon in Nice, using one of the largest telescopes of that time. The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summers) in combination with the canals led to speculation about life on Mars, and it was a long-held belief that Mars contained vast seas and vegetation. As bigger telescopes were used, fewer long, straight canali were observed. During observations in 1909 by Antoniadi with an 84-centimetre (33 in) telescope, irregular patterns were observed, but no canali were seen. The first spacecraft from Earth to visit Mars was Mars 1 of the Soviet Union, which flew by in 1963, but contact was lost en route. NASA's Mariner 4 followed and became the first spacecraft to successfully transmit from Mars; launched on 28 November 1964, it made its closest approach to the planet on 15 July 1965. Mariner 4 detected the weak Martian radiation belt, measured at about 0.1% that of Earth, and captured the first images of another planet from deep space. Once spacecraft visited the planet during the 1960s and 1970s, many previous concepts of Mars were radically broken. After the results of the Viking life-detection experiments, the hypothesis of a dead planet was generally accepted. The data from Mariner 9 and Viking allowed better maps of Mars to be made. Until 1997 and after Viking 1 shut down in 1982, Mars was only visited by three unsuccessful probes, two flying past without contact (Phobos 1, 1988; Mars Observer, 1993), and one (Phobos 2 1989) malfunctioning in orbit before reaching its destination Phobos. In 1997 Mars Pathfinder became the first successful rover mission beyond the Moon and started together with Mars Global Surveyor (operated until late 2006) an uninterrupted active robotic presence at Mars that has lasted until today. It produced complete, extremely detailed maps of the Martian topography, magnetic field and surface minerals. Starting with these missions a range of new improved crewless spacecraft, including orbiters, landers, and rovers, have been sent to Mars, with successful missions by the NASA (United States), Jaxa (Japan), ESA, United Kingdom, ISRO (India), Roscosmos (Russia), the United Arab Emirates, and CNSA (China) to study the planet's surface, climate, and geology, uncovering the different elements of the history and dynamic of the hydrosphere of Mars and possible traces of ancient life. As of 2023[update], Mars is host to ten functioning spacecraft. Eight are in orbit: 2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN, ExoMars Trace Gas Orbiter, the Hope orbiter, and the Tianwen-1 orbiter. Another two are on the surface: the Mars Science Laboratory Curiosity rover and the Perseverance rover. Collected maps are available online at websites including Google Mars. NASA provides two online tools: Mars Trek, which provides visualizations of the planet using data from 50 years of exploration, and Experience Curiosity, which simulates traveling on Mars in 3-D with Curiosity. Planned missions to Mars include: As of February 2024[update], debris from these types of missions has reached over seven tons. Most of it consists of crashed and inactive spacecraft as well as discarded components. In April 2024, NASA selected several companies to begin studies on providing commercial services to further enable robotic science on Mars. Key areas include establishing telecommunications, payload delivery and surface imaging. Habitability and habitation During the late 19th century, it was widely accepted in the astronomical community that Mars had life-supporting qualities, including the presence of oxygen and water. However, in 1894 W. W. Campbell at Lick Observatory observed the planet and found that "if water vapor or oxygen occur in the atmosphere of Mars it is in quantities too small to be detected by spectroscopes then available". That observation contradicted many of the measurements of the time and was not widely accepted. Campbell and V. M. Slipher repeated the study in 1909 using better instruments, but with the same results. It was not until the findings were confirmed by W. S. Adams in 1925 that the myth of the Earth-like habitability of Mars was finally broken. However, even in the 1960s, articles were published on Martian biology, putting aside explanations other than life for the seasonal changes on Mars. The current understanding of planetary habitability – the ability of a world to develop environmental conditions favorable to the emergence of life – favors planets that have liquid water on their surface. Most often this requires the orbit of a planet to lie within the habitable zone, which for the Sun is estimated to extend from within the orbit of Earth to about that of Mars. During perihelion, Mars dips inside this region, but Mars's thin (low-pressure) atmosphere prevents liquid water from existing over large regions for extended periods. The past flow of liquid water demonstrates the planet's potential for habitability. Recent evidence has suggested that any water on the Martian surface may have been too salty and acidic to support regular terrestrial life. The environmental conditions on Mars are a challenge to sustaining organic life: the planet has little heat transfer across its surface, it has poor insulation against bombardment by the solar wind due to the absence of a magnetosphere and has insufficient atmospheric pressure to retain water in a liquid form (water instead sublimes to a gaseous state). Mars is nearly, or perhaps totally, geologically dead; the end of volcanic activity has apparently stopped the recycling of chemicals and minerals between the surface and interior of the planet. Evidence suggests that the planet was once significantly more habitable than it is today, but whether living organisms ever existed there remains unknown. The Viking probes of the mid-1970s carried experiments designed to detect microorganisms in Martian soil at their respective landing sites and had positive results, including a temporary increase in CO2 production on exposure to water and nutrients. This sign of life was later disputed by scientists, resulting in a continuing debate, with NASA scientist Gilbert Levin asserting that Viking may have found life. A 2014 analysis of Martian meteorite EETA79001 found chlorate, perchlorate, and nitrate ions in sufficiently high concentrations to suggest that they are widespread on Mars. UV and X-ray radiation would turn chlorate and perchlorate ions into other, highly reactive oxychlorines, indicating that any organic molecules would have to be buried under the surface to survive. Small quantities of methane and formaldehyde detected by Mars orbiters are both claimed to be possible evidence for life, as these chemical compounds would quickly break down in the Martian atmosphere. Alternatively, these compounds may instead be replenished by volcanic or other geological means, such as serpentinite. Impact glass, formed by the impact of meteors, which on Earth can preserve signs of life, has also been found on the surface of the impact craters on Mars. Likewise, the glass in impact craters on Mars could have preserved signs of life, if life existed at the site. The Cheyava Falls rock discovered on Mars in June 2024 has been designated by NASA as a "potential biosignature" and was core sampled by the Perseverance rover for possible return to Earth and further examination. Although highly intriguing, no definitive final determination on a biological or abiotic origin of this rock can be made with the data currently available. Several plans for a human mission to Mars have been proposed, but none have come to fruition. The NASA Authorization Act of 2017 directed NASA to study the feasibility of a crewed Mars mission in the early 2030s; the resulting report concluded that this would be unfeasible. In addition, in 2021, China was planning to send a crewed Mars mission in 2033. Privately held companies such as SpaceX have also proposed plans to send humans to Mars, with the eventual goal to settle on the planet. As of 2024, SpaceX has proceeded with the development of the Starship launch vehicle with the goal of Mars colonization. In plans shared with the company in April 2024, Elon Musk envisions the beginning of a Mars colony within the next twenty years. This would be enabled by the planned mass manufacturing of Starship and initially sustained by resupply from Earth, and in situ resource utilization on Mars, until the Mars colony reaches full self sustainability. Any future human mission to Mars will likely take place within the optimal Mars launch window, which occurs every 26 months. The moon Phobos has been proposed as an anchor point for a space elevator. Besides national space agencies and space companies, groups such as the Mars Society and The Planetary Society advocate for human missions to Mars. In culture Mars is named after the Roman god of war (Greek Ares), but was also associated with the demi-god Heracles (Roman Hercules) by ancient Greek astronomers, as detailed by Aristotle. This association between Mars and war dates back at least to Babylonian astronomy, in which the planet was named for the god Nergal, deity of war and destruction. It persisted into modern times, as exemplified by Gustav Holst's orchestral suite The Planets, whose famous first movement labels Mars "The Bringer of War". The planet's symbol, a circle with a spear pointing out to the upper right, is also used as a symbol for the male gender. The symbol dates from at least the 11th century, though a possible predecessor has been found in the Greek Oxyrhynchus Papyri. The idea that Mars was populated by intelligent Martians became widespread in the late 19th century. Schiaparelli's "canali" observations combined with Percival Lowell's books on the subject put forward the standard notion of a planet that was a drying, cooling, dying world with ancient civilizations constructing irrigation works. Many other observations and proclamations by notable personalities added to what has been termed "Mars Fever". In the present day, high-resolution mapping of the surface of Mars has revealed no artifacts of habitation, but pseudoscientific speculation about intelligent life on Mars still continues. Reminiscent of the canali observations, these speculations are based on small scale features perceived in the spacecraft images, such as "pyramids" and the "Face on Mars". In his book Cosmos, planetary astronomer Carl Sagan wrote: "Mars has become a kind of mythic arena onto which we have projected our Earthly hopes and fears." The depiction of Mars in fiction has been stimulated by its dramatic red color and by nineteenth-century scientific speculations that its surface conditions might support not just life but intelligent life. This gave way to many science fiction stories involving these concepts, such as H. G. Wells's The War of the Worlds, in which Martians seek to escape their dying planet by invading Earth; Ray Bradbury's The Martian Chronicles, in which human explorers accidentally destroy a Martian civilization; as well as Edgar Rice Burroughs's series Barsoom, C. S. Lewis's novel Out of the Silent Planet (1938), and a number of Robert A. Heinlein stories before the mid-sixties. Since then, depictions of Martians have also extended to animation. A comic figure of an intelligent Martian, Marvin the Martian, appeared in Haredevil Hare (1948) as a character in the Looney Tunes animated cartoons of Warner Brothers, and has continued as part of popular culture to the present. After the Mariner and Viking spacecraft had returned pictures of Mars as a lifeless and canal-less world, these ideas about Mars were abandoned; for many science-fiction authors, the new discoveries initially seemed like a constraint, but eventually the post-Viking knowledge of Mars became itself a source of inspiration for works like Kim Stanley Robinson's Mars trilogy. See also Notes References Further reading External links Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Local Sheet → Local Volume → Virgo Supercluster → Laniakea Supercluster → Pisces–Cetus Supercluster Complex → Local Hole → Observable universe → UniverseEach arrow (→) may be read as "within" or "part of". |
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Contents Meta Platforms Meta Platforms, Inc. (doing business as Meta) is an American multinational technology company headquartered in Menlo Park, California. Meta owns and operates several prominent social media platforms and communication services, including Facebook, Instagram, WhatsApp, Messenger, Threads and Manus. The company also operates an advertising network for its own sites and third parties; as of 2023[update], advertising accounted for 97.8 percent of its total revenue. Meta has been described as a part of Big Tech, which refers to the largest six tech companies in the United States, Alphabet (Google), Amazon, Apple, Meta (Facebook), Microsoft, and Nvidia, which are also the largest companies in the world by market capitalization. The company was originally established in 2004 as TheFacebook, Inc., and was renamed Facebook, Inc. in 2005. In 2021, it rebranded as Meta Platforms, Inc. to reflect a strategic shift toward developing the metaverse—an interconnected digital ecosystem spanning virtual and augmented reality technologies. In 2023, Meta was ranked 31st on the Forbes Global 2000 list of the world's largest public companies. As of 2022, it was the world's third-largest spender on research and development, with R&D expenses totaling US$35.3 billion. History Facebook filed for an initial public offering (IPO) on January 1, 2012. The preliminary prospectus stated that the company sought to raise $5 billion, had 845 million monthly active users, and a website accruing 2.7 billion likes and comments daily. After the IPO, Zuckerberg would retain 22% of the total shares and 57% of the total voting power in Facebook. Underwriters valued the shares at $38 each, valuing the company at $104 billion, the largest valuation yet for a newly public company. On May 16, one day before the IPO, Facebook announced it would sell 25% more shares than originally planned due to high demand. The IPO raised $16 billion, making it the third-largest in US history (slightly ahead of AT&T Mobility and behind only General Motors and Visa). The stock price left the company with a higher market capitalization than all but a few U.S. corporations—surpassing heavyweights such as Amazon, McDonald's, Disney, and Kraft Foods—and made Zuckerberg's stock worth $19 billion. The New York Times stated that the offering overcame questions about Facebook's difficulties in attracting advertisers to transform the company into a "must-own stock". Jimmy Lee of JPMorgan Chase described it as "the next great blue-chip". Writers at TechCrunch, on the other hand, expressed skepticism, stating, "That's a big multiple to live up to, and Facebook will likely need to add bold new revenue streams to justify the mammoth valuation." Trading in the stock, which began on May 18, was delayed that day due to technical problems with the Nasdaq exchange. The stock struggled to stay above the IPO price for most of the day, forcing underwriters to buy back shares to support the price. At the closing bell, shares were valued at $38.23, only $0.23 above the IPO price and down $3.82 from the opening bell value. The opening was widely described by the financial press as a disappointment. The stock set a new record for trading volume of an IPO. On May 25, 2012, the stock ended its first full week of trading at $31.91, a 16.5% decline. On May 22, 2012, regulators from Wall Street's Financial Industry Regulatory Authority announced that they had begun to investigate whether banks underwriting Facebook had improperly shared information only with select clients rather than the general public. Massachusetts Secretary of State William F. Galvin subpoenaed Morgan Stanley over the same issue. The allegations sparked "fury" among some investors and led to the immediate filing of several lawsuits, one of them a class action suit claiming more than $2.5 billion in losses due to the IPO. Bloomberg estimated that retail investors may have lost approximately $630 million on Facebook stock since its debut. S&P Global Ratings added Facebook to its S&P 500 index on December 21, 2013. On May 2, 2014, Zuckerberg announced that the company would be changing its internal motto from "Move fast and break things" to "Move fast with stable infrastructure". The earlier motto had been described as Zuckerberg's "prime directive to his developers and team" in a 2009 interview in Business Insider, in which he also said, "Unless you are breaking stuff, you are not moving fast enough." In November 2016, Facebook announced the Microsoft Windows client of gaming service Facebook Gameroom, formerly Facebook Games Arcade, at the Unity Technologies developers conference. The client allows Facebook users to play "native" games in addition to its web games. The service was closed in June 2021. Lasso was a short-video sharing app from Facebook similar to TikTok that was launched on iOS and Android in 2018 and was aimed at teenagers. On July 2, 2020, Facebook announced that Lasso would be shutting down on July 10. In 2018, the Oculus lead Jason Rubin sent his 50-page vision document titled "The Metaverse" to Facebook's leadership. In the document, Rubin acknowledged that Facebook's virtual reality business had not caught on as expected, despite the hundreds of millions of dollars spent on content for early adopters. He also urged the company to execute fast and invest heavily in the vision, to shut out HTC, Apple, Google and other competitors in the VR space. Regarding other players' participation in the metaverse vision, he called for the company to build the "metaverse" to prevent their competitors from "being in the VR business in a meaningful way at all". In May 2019, Facebook founded Libra Networks, reportedly to develop their own stablecoin cryptocurrency. Later, it was reported that Libra was being supported by financial companies such as Visa, Mastercard, PayPal and Uber. The consortium of companies was expected to pool in $10 million each to fund the launch of the cryptocurrency coin named Libra. Depending on when it would receive approval from the Swiss Financial Market Supervisory authority to operate as a payments service, the Libra Association had planned to launch a limited format cryptocurrency in 2021. Libra was renamed Diem, before being shut down and sold in January 2022 after backlash from Swiss government regulators and the public. During the COVID-19 pandemic, the use of online services, including Facebook, grew globally. Zuckerberg predicted this would be a "permanent acceleration" that would continue after the pandemic. Facebook hired aggressively, growing from 48,268 employees in March 2020 to more than 87,000 by September 2022. Following a period of intense scrutiny and damaging whistleblower leaks, news started to emerge on October 21, 2021 about Facebook's plan to rebrand the company and change its name. In the Q3 2021 earnings call on October 25, Mark Zuckerberg discussed the ongoing criticism of the company's social services and the way it operates, and pointed to the pivoting efforts to building the metaverse – without mentioning the rebranding and the name change. The metaverse vision and the name change from Facebook, Inc. to Meta Platforms was introduced at Facebook Connect on October 28, 2021. Based on Facebook's PR campaign, the name change reflects the company's shifting long term focus of building the metaverse, a digital extension of the physical world by social media, virtual reality and augmented reality features. "Meta" had been registered as a trademark in the United States in 2018 (after an initial filing in 2015) for marketing, advertising, and computer services, by a Canadian company that provided big data analysis of scientific literature. This company was acquired in 2017 by the Chan Zuckerberg Initiative (CZI), a foundation established by Zuckerberg and his wife, Priscilla Chan, and became one of their projects. Following the rebranding announcement, CZI announced that it had already decided to deprioritize the earlier Meta project, thus it would be transferring its rights to the name to Meta Platforms, and the previous project would end in 2022. Soon after the rebranding, in early February 2022, Meta reported a greater-than-expected decline in profits in the fourth quarter of 2021. It reported no growth in monthly users, and indicated it expected revenue growth to stall. It also expected measures taken by Apple Inc. to protect user privacy to cost it some $10 billion in advertisement revenue, an amount equal to roughly 8% of its revenue for 2021. In meeting with Meta staff the day after earnings were reported, Zuckerberg blamed competition for user attention, particularly from video-based apps such as TikTok. The 27% reduction in the company's share price which occurred in reaction to the news eliminated some $230 billion of value from Meta's market capitalization. Bloomberg described the decline as "an epic rout that, in its sheer scale, is unlike anything Wall Street or Silicon Valley has ever seen". Zuckerberg's net worth fell by as much as $31 billion. Zuckerberg owns 13% of Meta, and the holding makes up the bulk of his wealth. According to published reports by Bloomberg on March 30, 2022, Meta turned over data such as phone numbers, physical addresses, and IP addresses to hackers posing as law enforcement officials using forged documents. The law enforcement requests sometimes included forged signatures of real or fictional officials. When asked about the allegations, a Meta representative said, "We review every data request for legal sufficiency and use advanced systems and processes to validate law enforcement requests and detect abuse." In June 2022, Sheryl Sandberg, the chief operating officer of 14 years, announced she would step down that year. Zuckerberg said that Javier Olivan would replace Sandberg, though in a “more traditional” role. In March 2022, Meta (except Meta-owned WhatsApp) and Instagram were banned in Russia and added to the Russian list of terrorist and extremist organizations for alleged Russophobia and hate speech (up to genocidal calls) amid the ongoing Russian invasion of Ukraine. Meta appealed against the ban, but it was upheld by a Moscow court in June of the same year. Also in March 2022, Meta and Italian eyewear giant Luxottica released Ray-Ban Stories, a series of smartglasses which could play music and take pictures. Meta and Luxottica parent company EssilorLuxottica declined to disclose sales on the line of products as of September 2022, though Meta has expressed satisfaction with its customer feedback. In July 2022, Meta saw its first year-on-year revenue decline when its total revenue slipped by 1% to $28.8bn. Analysts and journalists accredited the loss to its advertising business, which has been limited by Apple's app tracking transparency feature and the number of people who have opted not to be tracked by Meta apps. Zuckerberg also accredited the decline to increasing competition from TikTok. On October 27, 2022, Meta's market value dropped to $268 billion, a loss of around $700 billion compared to 2021, and its shares fell by 24%. It lost its spot among the top 20 US companies by market cap, despite reaching the top 5 in the previous year. In November 2022, Meta laid off 11,000 employees, 13% of its workforce. Zuckerberg said the decision to aggressively increase Meta's investments had been a mistake, as he had wrongly predicted that the surge in e-commerce would last beyond the COVID-19 pandemic. He also attributed the decline to increased competition, a global economic downturn and "ads signal loss". Plans to lay off a further 10,000 employees began in April 2023. The layoffs were part of a general downturn in the technology industry, alongside layoffs by companies including Google, Amazon, Tesla, Snap, Twitter and Lyft. Starting from 2022, Meta scrambled to catch up to other tech companies in adopting specialized artificial intelligence hardware and software. It had been using less expensive CPUs instead of GPUs for AI work, but that approach turned out to be less efficient. The company gifted the Inter-university Consortium for Political and Social Research $1.3 million to finance the Social Media Archive's aim to make their data available to social science research. In 2023, Ireland's Data Protection Commissioner imposed a record EUR 1.2 billion fine on Meta for transferring data from Europe to the United States without adequate protections for EU citizens.: 250 In March 2023, Meta announced a new round of layoffs that would cut 10,000 employees and close 5,000 open positions to make the company more efficient. Meta revenue surpassed analyst expectations for the first quarter of 2023 after announcing that it was increasing its focus on AI. On July 6, Meta launched a new app, Threads, a competitor to Twitter. Meta announced its artificial intelligence model Llama 2 in July 2023, available for commercial use via partnerships with major cloud providers like Microsoft. It was the first project to be unveiled out of Meta's generative AI group after it was set up in February. It would not charge access or usage but instead operate with an open-source model to allow Meta to ascertain what improvements need to be made. Prior to this announcement, Meta said it had no plans to release Llama 2 for commercial use. An earlier version of Llama was released to academics. In August 2023, Meta announced its permanent removal of news content from Facebook and Instagram in Canada due to the Online News Act, which requires Canadian news outlets to be compensated for content shared on its platform. The Online News Act was in effect by year-end, but Meta will not participate in the regulatory process. In October 2023, Zuckerberg said that AI would be Meta's biggest investment area in 2024. Meta finished 2023 as one of the best-performing technology stocks of the year, with its share price up 150 percent. Its stock reached an all-time high in January 2024, bringing Meta within 2% of achieving $1 trillion market capitalization. In November 2023 Meta Platforms launched an ad-free service in Europe, allowing subscribers to opt-out of personal data being collected for targeted advertising. A group of 28 European organizations, including Max Schrems' advocacy group NOYB, the Irish Council for Civil Liberties, Wikimedia Europe, and the Electronic Privacy Information Center, signed a 2024 letter to the European Data Protection Board (EDPB) expressing concern that this subscriber model would undermine privacy protections, specifically GDPR data protection standards. Meta removed the Facebook and Instagram accounts of Iran's Supreme Leader Ali Khamenei in February 2024, citing repeated violations of its Dangerous Organizations & Individuals policy. As of March, Meta was under investigation by the FDA for alleged use of their social media platforms to sell illegal drugs. On 16 May 2024, the European Commission began an investigation into Meta over concerns related to child safety. In May 2023, Iraqi social media influencer Esaa Ahmed-Adnan encountered a troubling issue when Instagram removed his posts, citing false copyright violations despite his content being original and free from copyrighted material. He discovered that extortionists were behind these takedowns, offering to restore his content for $3,000 or provide ongoing protection for $1,000 per month. This scam, exploiting Meta’s rights management tools, became widespread in the Middle East, revealing a gap in Meta’s enforcement in developing regions. An Iraqi nonprofit Tech4Peace’s founder, Aws al-Saadi helped Ahmed-Adnan and others, but the restoration process was slow, leading to significant financial losses for many victims, including prominent figures like Ammar al-Hakim. This situation highlighted Meta’s challenges in balancing global growth with effective content moderation and protection. On 16 September 2024, Meta announced it had banned Russian state media outlets from its platforms worldwide due to concerns about "foreign interference activity." This decision followed allegations that RT and its employees funneled $10 million through shell companies to secretly fund influence campaigns on various social media channels. Meta's actions were part of a broader effort to counter Russian covert influence operations, which had intensified since the invasion. At its 2024 Connect conference, Meta presented Orion, its first pair of augmented reality glasses. Though Orion was originally intended to be sold to consumers, the manufacturing process turned out to be too complex and expensive. Instead, the company pivoted to producing a small number of the glasses to be used internally. On 4 October 2024, Meta announced about its new AI model called Movie Gen, capable of generating realistic video and audio clips based on user prompts. Meta stated it would not release Movie Gen for open development, preferring to collaborate directly with content creators and integrate it into its products by the following year. The model was built using a combination of licensed and publicly available datasets. On October 31, 2024, ProPublica published an investigation into deceptive political advertisement scams that sometimes use hundreds of hijacked profiles and facebook pages run by organized networks of scammers. The authors cited spotty enforcement by Meta as a major reason for the extent of the issue. In November 2024, TechCrunch reported that Meta were considering building a $10bn global underwater cable spanning 25,000 miles. In the same month, Meta closed down 2 million accounts on Facebook and Instagram that were linked to scam centers in Myanmar, Laos, Cambodia, the Philippines, and the United Arab Emirates doing pig butchering scams. In December 2024, Meta announced that, beginning February 2025, they would require advertisers to run ads about financial services in Australia to verify information about who are the beneficiary and the payer in a bid to regulate scams. On December 4, 2024, Meta announced it will invest US$10 billion for its largest AI data center in northeast Louisiana, powered by natural gas facilities. On the 11th of that month, Meta experienced a global outage, impacting accounts on all of their social media and messaging applications. Outage reports from DownDetector reached 70,000+ and 100,000+ within minutes for Instagram and Facebook, respectively. In January 2025, Meta announced plans to roll back its diversity, equity, and inclusion (DEI) initiatives, citing shifts in the "legal and policy landscape" in the United States following the 2024 presidential election. The decision followed reports that CEO Mark Zuckerberg sought to align the company more closely with the incoming Trump administration, including changes to content moderation policies and executive leadership. The new content moderation policies continued to bar insults about a person's intellect or mental illness, but made an exception to allow calling LGBTQ people mentally ill because they are gay or transgender. Later that month, Meta agreed to pay $25 million to settle a 2021 lawsuit brought by Donald Trump for suspending his social media accounts after the January 6 riots. Changes to Meta's moderation policies were controversial among its oversight board, with a significant divide in opinion between the board's US conservatives and its global members. In June 2025, Meta Platforms Inc. has decided to make a multibillion-dollar investment into artificial intelligence startup Scale AI. The financing could exceed $10 billion in value which would make it one of the largest private company funding events of all time. In October 2025, it was announced that Meta would be laying off 600 employees in the artificial intelligence unit to perform better and simpler. They referred to their AI unit as "bloated" and are seeking to trim down the department. This mass layoff is going to impact Meta’s AI infrastructure units, Fundamental Artificial Intelligence Research unit (FAIR) and other product-related positions. Mergers and acquisitions Meta has acquired multiple companies (often identified as talent acquisitions). One of its first major acquisitions was in April 2012, when it acquired Instagram for approximately US$1 billion in cash and stock. In October 2013, Facebook, Inc. acquired Onavo, an Israeli mobile web analytics company. In February 2014, Facebook, Inc. announced it would buy mobile messaging company WhatsApp for US$19 billion in cash and stock. The acquisition was completed on October 6. Later that year, Facebook bought Oculus VR for $2.3 billion in cash and stock, which released its first consumer virtual reality headset in 2016. In late November 2019, Facebook, Inc. announced the acquisition of the game developer Beat Games, responsible for developing one of that year's most popular VR games, Beat Saber. In Late 2022, after Facebook Inc rebranded to Meta Platforms Inc, Oculus was rebranded to Meta Quest. In May 2020, Facebook, Inc. announced it had acquired Giphy for a reported cash price of $400 million. It will be integrated with the Instagram team. However, in August 2021, UK's Competition and Markets Authority (CMA) stated that Facebook, Inc. might have to sell Giphy, after an investigation found that the deal between the two companies would harm competition in display advertising market. Facebook, Inc. was fined $70 million by CMA for deliberately failing to report all information regarding the acquisition and the ongoing antitrust investigation. In October 2022, the CMA ruled for a second time that Meta be required to divest Giphy, stating that Meta already controls half of the advertising in the UK. Meta agreed to the sale, though it stated that it disagrees with the decision itself. In May 2023, Giphy was divested to Shutterstock for $53 million. In November 2020, Facebook, Inc. announced that it planned to purchase the customer-service platform and chatbot specialist startup Kustomer to promote companies to use their platform for business. It has been reported that Kustomer valued at slightly over $1 billion. The deal was closed in February 2022 after regulatory approval. In September 2022, Meta acquired Lofelt, a Berlin-based haptic tech startup. In December 2025, it was announced Meta had acquired the AI-wearables startup, Limitless. In the same month, they also acquired another AI startup, Manus AI, for $2 billion. Manus announced in December that its platform had achieved $100mm in recurring revenue just 8 months after its launch and Meta said it will scale the platform to many other businesses. In January 2026, it was announced Meta proposed acquisition of Manus was undergoing preliminary scrutiny by Chinese regulators. The examination concerns the cross-border transfer of artificial intelligence technology developed in China. Lobbying In 2020, Facebook, Inc. spent $19.7 million on lobbying, hiring 79 lobbyists. In 2019, it had spent $16.7 million on lobbying and had a team of 71 lobbyists, up from $12.6 million and 51 lobbyists in 2018. Facebook was the largest spender of lobbying money among the Big Tech companies in 2020. The lobbying team includes top congressional aide John Branscome, who was hired in September 2021, to help the company fend off threats from Democratic lawmakers and the Biden administration. In December 2024, Meta donated $1 million to the inauguration fund for then-President-elect Donald Trump. In 2025, Meta was listed among the donors funding the construction of the White House State Ballroom. Partnerships February 2026, Meta announced a long-term partnership with Nvidia. Censorship In August 2024, Mark Zuckerberg sent a letter to Jim Jordan indicating that during the COVID-19 pandemic the Biden administration repeatedly asked Meta to limit certain COVID-19 content, including humor and satire, on Facebook and Instagram. In 2016 Meta hired Jordana Cutler, formerly an employee at the Israeli Embassy to the United States, as its policy chief for Israel and the Jewish Diaspora. In this role, Cutler pushed for the censorship of accounts belonging to Students for Justice in Palestine chapters in the United States. Critics have said that Cutler's position gives the Israeli government an undue influence over Meta policy, and that few countries have such high levels of contact with Meta policymakers. Following the election of Donald Trump in 2025, various sources noted possible censorship related to the Democratic Party on Instagram and other Meta platforms. In February 2025, a Meta rep flagged journalist Gil Duran's article and other "critiques of tech industry figures" as spam or sensitive content, limiting their reach. In March 2025, Meta attempted to block former employee Sarah Wynn-Williams from promoting or further distributing her memoir, Careless People, that includes allegations of unaddressed sexual harassment in the workplace by senior executives. The New York Times reports that the arbitration is among Meta's most forcible attempts to repudiate a former employee's account of workplace dynamics. Publisher Macmillan reacted to the ruling by the Emergency International Arbitral Tribunal by stating that it will ignore its provisions. As of 15 March 2025[update], hardback and digital versions of Careless People were being offered for sale by major online retailers. From October 2025, Meta began removing and restricting access for accounts related to LGBTQ, reproductive health and abortion information pages on its platforms. Martha Dimitratou, executive director of Repro Uncensored, called Meta's shadow-banning of these issues "One of the biggest waves of censorship we are seeing". Disinformation concerns Since its inception, Meta has been accused of being a host for fake news and misinformation. In the wake of the 2016 United States presidential election, Zuckerberg began to take steps to eliminate the prevalence of fake news, as the platform had been criticized for its potential influence on the outcome of the election. The company initially partnered with ABC News, the Associated Press, FactCheck.org, Snopes and PolitiFact for its fact-checking initiative; as of 2018, it had over 40 fact-checking partners across the world, including The Weekly Standard. A May 2017 review by The Guardian found that the platform's fact-checking initiatives of partnering with third-party fact-checkers and publicly flagging fake news were regularly ineffective, and appeared to be having minimal impact in some cases. In 2018, journalists working as fact-checkers for the company criticized the partnership, stating that it had produced minimal results and that the company had ignored their concerns. In 2024 Meta's decision to continue to disseminate a falsified video of US president Joe Biden, even after it had been proven to be fake, attracted criticism and concern. In January 2025, Meta ended its use of third-party fact-checkers in favor of a user-run community notes system similar to the one used on X. While Zuckerberg supported these changes, saying that the amount of censorship on the platform was excessive, the decision received criticism by fact-checking institutions, stating that the changes would make it more difficult for users to identify misinformation. Meta also faced criticism for weakening its policies on hate speech that were designed to protect minorities and LGBTQ+ individuals from bullying and discrimination. While moving its content review teams from California to Texas, Meta changed their hateful conduct policy to eliminate restrictions on anti-LGBT and anti-immigrant hate speech, as well as explicitly allowing users to accuse LGBT people of being mentally ill or abnormal based on their sexual orientation or gender identity. In January 2025, Meta faced significant criticism for its role in removing LGBTQ+ content from its platforms, amid its broader efforts to address anti-LGBTQ+ hate speech. The removal of LGBTQ+ themes was noted as part of the wider crackdown on content deemed to violate its community guidelines. Meta's content moderation policies, which were designed to combat harmful speech and protect users from discrimination, inadvertently led to the removal or restriction of LGBTQ+ content, particularly posts highlighting LGBTQ+ identities, support, or political issues. According to reports, LGBTQ+ posts, including those that simply celebrated pride or advocated for LGBTQ+ rights, were flagged and removed for reasons that some critics argue were vague or inconsistently applied. Many LGBTQ+ activists and users on Meta's platforms expressed concern that such actions stifled visibility and expression, potentially isolating LGBTQ+ individuals and communities, especially in spaces that were historically important for outreach and support. Lawsuits Numerous lawsuits have been filed against the company, both when it was known as Facebook, Inc., and as Meta Platforms. In March 2020, the Office of the Australian Information Commissioner (OAIC) sued Facebook, for significant and persistent infringements of the rule on privacy involving the Cambridge Analytica fiasco. Every violation of the Privacy Act is subject to a theoretical cumulative liability of $1.7 million. The OAIC estimated that a total of 311,127 Australians had been exposed. On December 8, 2020, the U.S. Federal Trade Commission and 46 states (excluding Alabama, Georgia, South Carolina, and South Dakota), the District of Columbia and the territory of Guam, launched Federal Trade Commission v. Facebook as an antitrust lawsuit against Facebook. The lawsuit concerns Facebook's acquisition of two competitors—Instagram and WhatsApp—and the ensuing monopolistic situation. FTC alleges that Facebook holds monopolistic power in the U.S. social networking market and seeks to force the company to divest from Instagram and WhatsApp to break up the conglomerate. William Kovacic, a former chairman of the Federal Trade Commission, argued the case will be difficult to win as it would require the government to create a counterfactual argument of an internet where the Facebook-WhatsApp-Instagram entity did not exist, and prove that harmed competition or consumers. In November 2025, it was ruled that Meta did not violate antitrust laws and holds no monopoly in the market. On December 24, 2021, a court in Russia fined Meta for $27 million after the company declined to remove unspecified banned content. The fine was reportedly tied to the company's annual revenue in the country. In May 2022, a lawsuit was filed in Kenya against Meta and its local outsourcing company Sama. Allegedly, Meta has poor working conditions in Kenya for workers moderating Facebook posts. According to the lawsuit, 260 screeners were declared redundant with confusing reasoning. The lawsuit seeks financial compensation and an order that outsourced moderators be given the same health benefits and pay scale as Meta employees. In June 2022, 8 lawsuits were filed across the U.S. over the allege that excessive exposure to platforms including Facebook and Instagram has led to attempted or actual suicides, eating disorders and sleeplessness, among other issues. The litigation follows a former Facebook employee's testimony in Congress that the company refused to take responsibility. The company noted that tools have been developed for parents to keep track of their children's activity on Instagram and set time limits, in addition to Meta's "Take a break" reminders. In addition, the company is providing resources specific to eating disorders as well as developing AI to prevent children under the age of 13 signing up for Facebook or Instagram. In June 2022, Meta settled a lawsuit with the US Department of Justice. The lawsuit, which was filed in 2019, alleged that the company enabled housing discrimination through targeted advertising, as it allowed homeowners and landlords to run housing ads excluding people based on sex, race, religion, and other characteristics. The U.S. Department of Justice stated that this was in violation of the Fair Housing Act. Meta was handed a penalty of $115,054 and given until December 31, 2022, to shadow the algorithm tool. In January 2023, Meta was fined €390 million for violations of the European Union General Data Protection Regulation. In May 2023, the European Data Protection Board fined Meta a record €1.2 billion for breaching European Union data privacy laws by transferring personal data of Facebook users to servers in the U.S. In July 2024, Meta agreed to pay the state of Texas US$1.4 billion to settle a lawsuit brought by Texas Attorney General Ken Paxton accusing the company of collecting users' biometric data without consent, setting a record for the largest privacy-related settlement ever obtained by a state attorney general. In October 2024, Meta Platforms faced lawsuits in Japan from 30 plaintiffs who claimed they were defrauded by fake investment ads on Facebook and Instagram, featuring false celebrity endorsements. The plaintiffs are seeking approximately $2.8 million in damages. In April 2025, the Kenyan High Court ruled that a US$2.4 billion lawsuit in which three plaintiffs claim that Facebook inflamed civil violence in Ethiopia in 2021 could proceed. In April 2025, Meta was fined €200 million ($230 million) for breaking the Digital Markets Act, by imposing a “consent or pay” system that forces users to either allow their personal data to be used to target advertisements, or pay a subscription fee for advertising-free versions of Facebook and Instagram. In late April 2025, a case was filed against Meta in Ghana over the alleged psychological distress experienced by content moderators employed to take down disturbing social media content including depictions of murders, extreme violence and child sexual abuse. Meta moved the moderation service to the Ghanaian capital of Accra after legal issues in the previous location Kenya. The new moderation company is Teleperformance, a multinational corporation with a history of worker's rights violation. Reports suggests the conditions are worse here than in the previous Kenyan location, with many workers afraid of speaking out due to fear of returning to conflict zones. Workers reported developing mental illnesses, attempted suicides, and low pay. In 26 January 2026, a New Mexico state court case was filed, suggesting that Mark Zuckerberg approved allowing minors to access artificial intelligence chatbot companions that safety staffers warned were capable of sexual interactions. In 2020, the company UReputation, which had been involved in several cases concerning the management of digital armies[clarification needed], filed a lawsuit against Facebook, accusing it of unlawfully transmitting personal data to third parties. Legal actions were initiated in Tunisia, France, and the United States. In 2025, the United States District court for the Northern District of Georgia approved a discovery procedure, allowing UReputation to access documents and evidence held by Meta. Structure Meta's key management consists of: As of October 2022[update], Meta had 83,553 employees worldwide. As of June 2024[update], Meta's board consisted of the following directors; Meta Platforms is mainly owned by institutional investors, who hold around 80% of all shares. Insiders control the majority of voting shares. The three largest individual investors in 2024 were Mark Zuckerberg, Sheryl Sandberg and Christopher K. Cox. The largest shareholders in late 2024/early 2025 were: Roger McNamee, an early Facebook investor and Zuckerberg's former mentor, said Facebook had "the most centralized decision-making structure I have ever encountered in a large company". Facebook co-founder Chris Hughes has stated that chief executive officer Mark Zuckerberg has too much power, that the company is now a monopoly, and that, as a result, it should be split into multiple smaller companies. In an op-ed in The New York Times, Hughes said he was concerned that Zuckerberg had surrounded himself with a team that did not challenge him, and that it is the U.S. government's job to hold him accountable and curb his "unchecked power". He also said that "Mark's power is unprecedented and un-American." Several U.S. politicians agreed with Hughes. European Union Commissioner for Competition Margrethe Vestager stated that splitting Facebook should be done only as "a remedy of the very last resort", and that it would not solve Facebook's underlying problems. Revenue Facebook ranked No. 34 in the 2020 Fortune 500 list of the largest United States corporations by revenue, with almost $86 billion in revenue most of it coming from advertising. One analysis of 2017 data determined that the company earned US$20.21 per user from advertising. According to New York, since its rebranding, Meta has reportedly lost $500 billion as a result of new privacy measures put in place by companies such as Apple and Google which prevents Meta from gathering users' data. In February 2015, Facebook announced it had reached two million active advertisers, with most of the gain coming from small businesses. An active advertiser was defined as an entity that had advertised on the Facebook platform in the last 28 days. In March 2016, Facebook announced it had reached three million active advertisers with more than 70% from outside the United States. Prices for advertising follow a variable pricing model based on auctioning ad placements, and potential engagement levels of the advertisement itself. Similar to other online advertising platforms like Google and Twitter, targeting of advertisements is one of the chief merits of digital advertising compared to traditional media. Marketing on Meta is employed through two methods based on the viewing habits, likes and shares, and purchasing data of the audience, namely targeted audiences and "look alike" audiences. The U.S. IRS challenged the valuation Facebook used when it transferred IP from the U.S. to Facebook Ireland (now Meta Platforms Ireland) in 2010 (which Facebook Ireland then revalued higher before charging out), as it was building its double Irish tax structure. The case is ongoing and Meta faces a potential fine of $3–5bn. The U.S. Tax Cuts and Jobs Act of 2017 changed Facebook's global tax calculations. Meta Platforms Ireland is subject to the U.S. GILTI tax of 10.5% on global intangible profits (i.e. Irish profits). On the basis that Meta Platforms Ireland Limited is paying some tax, the effective minimum US tax for Facebook Ireland will be circa 11%. In contrast, Meta Platforms Inc. would incur a special IP tax rate of 13.125% (the FDII rate) if its Irish business relocated to the U.S. Tax relief in the U.S. (21% vs. Irish at the GILTI rate) and accelerated capital expensing, would make this effective U.S. rate around 12%. The insignificance of the U.S./Irish tax difference was demonstrated when Facebook moved 1.5bn non-EU accounts to the U.S. to limit exposure to GDPR. Facilities Users outside of the U.S. and Canada contract with Meta's Irish subsidiary, Meta Platforms Ireland Limited (formerly Facebook Ireland Limited), allowing Meta to avoid US taxes for all users in Europe, Asia, Australia, Africa and South America. Meta is making use of the Double Irish arrangement which allows it to pay 2–3% corporation tax on all international revenue. In 2010, Facebook opened its fourth office, in Hyderabad, India, which houses online advertising and developer support teams and provides support to users and advertisers. In India, Meta is registered as Facebook India Online Services Pvt Ltd. It also has offices or planned sites in Chittagong, Bangladesh; Dublin, Ireland; and Austin, Texas, among other cities. Facebook opened its London headquarters in 2017 in Fitzrovia in central London. Facebook opened an office in Cambridge, Massachusetts in 2018. The offices were initially home to the "Connectivity Lab", a group focused on bringing Internet access to those who do not have access to the Internet. In April 2019, Facebook opened its Taiwan headquarters in Taipei. In March 2022, Meta opened new regional headquarters in Dubai. In September 2023, it was reported that Meta had paid £149m to British Land to break the lease on Triton Square London office. Meta reportedly had another 18 years left on its lease on the site. As of 2023, Facebook operated 21 data centers. It committed to purchase 100% renewable energy and to reduce its greenhouse gas emissions 75% by 2020. Its data center technologies include Fabric Aggregator, a distributed network system that accommodates larger regions and varied traffic patterns. Reception US Representative Alexandria Ocasio-Cortez responded in a tweet to Zuckerberg's announcement about Meta, saying: "Meta as in 'we are a cancer to democracy metastasizing into a global surveillance and propaganda machine for boosting authoritarian regimes and destroying civil society ... for profit!'" Ex-Facebook employee Frances Haugen and whistleblower behind the Facebook Papers responded to the rebranding efforts by expressing doubts about the company's ability to improve while led by Mark Zuckerberg, and urged the chief executive officer to resign. In November 2021, a video published by Inspired by Iceland went viral, in which a Zuckerberg look-alike promoted the Icelandverse, a place of "enhanced actual reality without silly looking headsets". In a December 2021 interview, SpaceX and Tesla chief executive officer Elon Musk said he could not see a compelling use-case for the VR-driven metaverse, adding: "I don't see someone strapping a frigging screen to their face all day." In January 2022, Louise Eccles of The Sunday Times logged into the metaverse with the intention of making a video guide. She wrote: Initially, my experience with the Oculus went well. I attended work meetings as an avatar and tried an exercise class set in the streets of Paris. The headset enabled me to feel the thrill of carving down mountains on a snowboard and the adrenaline rush of climbing a mountain without ropes. Yet switching to the social apps, where you mingle with strangers also using VR headsets, it was at times predatory and vile. Eccles described being sexually harassed by another user, as well as "accents from all over the world, American, Indian, English, Australian, using racist, sexist, homophobic and transphobic language". She also encountered users as young as 7 years old on the platform, despite Oculus headsets being intended for users over 13. See also References External links 37°29′06″N 122°08′54″W / 37.48500°N 122.14833°W / 37.48500; -122.14833 |
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Editing Template:Constellations/modern Copy and paste: – — ° ′ ″ ≈ ≠ ≤ ≥ ± − × ÷ ← → · § Sign your posts on talk pages: ~~~~ Cite your sources: <ref></ref> {{}} {{{}}} | [] [[]] [[Category:]] #REDIRECT [[]] <s></s> <sup></sup> <sub></sub> <code></code> <pre></pre> <blockquote></blockquote> <ref></ref> <ref name="" /> {{Reflist}} <references /> <includeonly></includeonly> <noinclude></noinclude> {{DEFAULTSORT:}} <nowiki></nowiki> <!-- --> <span class="plainlinks"></span> Symbols: ~ | ¡ ¿ † ‡ ↔ ↑ ↓ • ¶ # ∞ ‹› «» ¤ ₳ ฿ ₵ ¢ ₡ ₢ $ ₫ ₯ € ₠ ₣ ƒ ₴ ₭ ₤ ℳ ₥ ₦ ₧ ₰ £ ៛ ₨ ₪ ৳ ₮ ₩ ¥ ♠ ♣ ♥ ♦ 𝄫 ♭ ♮ ♯ 𝄪 © ¼ ½ ¾ Latin: A a Á á À à  â Ä ä Ǎ ǎ Ă ă Ā ā à ã Å å Ą ą Æ æ Ǣ ǣ B b C c Ć ć Ċ ċ Ĉ ĉ Č č Ç ç D d Ď ď Đ đ Ḍ ḍ Ð ð E e É é È è Ė ė Ê ê Ë ë Ě ě Ĕ ĕ Ē ē Ẽ ẽ Ę ę Ẹ ẹ Ɛ ɛ Ǝ ǝ Ə ə F f G g Ġ ġ Ĝ ĝ Ğ ğ Ģ ģ H h Ĥ ĥ Ħ ħ Ḥ ḥ I i İ ı Í í Ì ì Î î Ï ï Ǐ ǐ Ĭ ĭ Ī ī Ĩ ĩ Į į Ị ị J j Ĵ ĵ K k Ķ ķ L l Ĺ ĺ Ŀ ŀ Ľ ľ Ļ ļ Ł ł Ḷ ḷ Ḹ ḹ M m Ṃ ṃ N n Ń ń Ň ň Ñ ñ Ņ ņ Ṇ ṇ Ŋ ŋ O o Ó ó Ò ò Ô ô Ö ö Ǒ ǒ Ŏ ŏ Ō ō Õ õ Ǫ ǫ Ọ ọ Ő ő Ø ø Œ œ Ɔ ɔ P p Q q R r Ŕ ŕ Ř ř Ŗ ŗ Ṛ ṛ Ṝ ṝ S s Ś ś Ŝ ŝ Š š Ş ş Ș ș Ṣ ṣ ß T t Ť ť Ţ ţ Ț ț Ṭ ṭ Þ þ U u Ú ú Ù ù Û û Ü ü Ǔ ǔ Ŭ ŭ Ū ū Ũ ũ Ů ů Ų ų Ụ ụ Ű ű Ǘ ǘ Ǜ ǜ Ǚ ǚ Ǖ ǖ V v W w Ŵ ŵ X x Y y Ý ý Ŷ ŷ Ÿ ÿ Ỹ ỹ Ȳ ȳ Z z Ź ź Ż ż Ž ž ß Ð ð Þ þ Ŋ ŋ Ə ə Greek: Ά ά Έ έ Ή ή Ί ί Ό ό Ύ ύ Ώ ώ Α α Β β Γ γ Δ δ Ε ε Ζ ζ Η η Θ θ Ι ι Κ κ Λ λ Μ μ Ν ν Ξ ξ Ο ο Π π Ρ ρ Σ σ ς Τ τ Υ υ Φ φ Χ χ Ψ ψ Ω ω {{Polytonic|}} Cyrillic: А а Б б В в Г г Ґ ґ Ѓ ѓ Д д Ђ ђ Е е Ё ё Є є Ж ж З з Ѕ ѕ И и І і Ї ї Й й Ј ј К к Ќ ќ Л л Љ љ М м Н н Њ њ О о П п Р р С с Т т Ћ ћ У у Ў ў Ф ф Х х Ц ц Ч ч Џ џ Ш ш Щ щ Ъ ъ Ы ы Ь ь Э э Ю ю Я я ́ IPA: t̪ d̪ ʈ ɖ ɟ ɡ ɢ ʡ ʔ ɸ β θ ð ʃ ʒ ɕ ʑ ʂ ʐ ç ʝ ɣ χ ʁ ħ ʕ ʜ ʢ ɦ ɱ ɳ ɲ ŋ ɴ ʋ ɹ ɻ ɰ ʙ ⱱ ʀ ɾ ɽ ɫ ɬ ɮ ɺ ɭ ʎ ʟ ɥ ʍ ɧ ʼ ɓ ɗ ʄ ɠ ʛ ʘ ǀ ǃ ǂ ǁ ɨ ʉ ɯ ɪ ʏ ʊ ø ɘ ɵ ɤ ə ɚ ɛ œ ɜ ɝ ɞ ʌ ɔ æ ɐ ɶ ɑ ɒ ʰ ʱ ʷ ʲ ˠ ˤ ⁿ ˡ ˈ ˌ ː ˑ ̪ {{IPA|}} Wikidata entities used in this page Pages transcluded onto the current version of this page (help): |
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Contents Python (programming language) Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically type-checked and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language. Python 3.0, released in 2008, was a major revision and not completely backward-compatible with earlier versions. Beginning with Python 3.5, capabilities and keywords for typing were added to the language, allowing optional static typing. As of 2026[update], the Python Software Foundation supports Python 3.10, 3.11, 3.12, 3.13, and 3.14, following the project's annual release cycle and five-year support policy. Python 3.15 is currently in the alpha development phase, and the stable release is expected to come out in October 2026. Earlier versions in the 3.x series have reached end-of-life and no longer receive security updates. Python has gained widespread use in the machine learning community. It is widely taught as an introductory programming language. Since 2003, Python has consistently ranked in the top ten of the most popular programming languages in the TIOBE Programming Community Index, which ranks based on searches in 24 platforms. History Python was conceived in the late 1980s by Guido van Rossum at Centrum Wiskunde & Informatica (CWI) in the Netherlands. It was designed as a successor to the ABC programming language, which was inspired by SETL, capable of exception handling and interfacing with the Amoeba operating system. Python implementation began in December 1989. Van Rossum first released it in 1991 as Python 0.9.0. Van Rossum assumed sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from responsibilities as Python's "benevolent dictator for life" (BDFL); this title was bestowed on him by the Python community to reflect his long-term commitment as the project's chief decision-maker. (He has since come out of retirement and is self-titled "BDFL-emeritus".) In January 2019, active Python core developers elected a five-member Steering Council to lead the project. The name Python derives from the British comedy series Monty Python's Flying Circus. (See § Naming.) Python 2.0 was released on 16 October 2000, featuring many new features such as list comprehensions, cycle-detecting garbage collection, reference counting, and Unicode support. Python 2.7's end-of-life was initially set for 2015, and then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python 3. It no longer receives security patches or updates. While Python 2.7 and older versions are officially unsupported, a different unofficial Python implementation, PyPy, continues to support Python 2, i.e., "2.7.18+" (plus 3.11), with the plus signifying (at least some) "backported security updates". Python 3.0 was released on 3 December 2008, and was a major revision and not completely backward-compatible with earlier versions, with some new semantics and changed syntax. Python 2.7.18, released in 2020, was the last release of Python 2. Several releases in the Python 3.x series have added new syntax to the language, and made a few (considered very minor) backward-incompatible changes. As of January 2026[update], Python 3.14.3 is the latest stable release. All older 3.x versions had a security update down to Python 3.9.24 then again with 3.9.25, the final version in 3.9 series. Python 3.10 is, since November 2025, the oldest supported branch. Python 3.15 has an alpha released, and Android has an official downloadable executable available for Python 3.14. Releases receive two years of full support followed by three years of security support. Design philosophy and features Python is a multi-paradigm programming language. Object-oriented programming and structured programming are fully supported, and many of their features support functional programming and aspect-oriented programming – including metaprogramming and metaobjects. Many other paradigms are supported via extensions, including design by contract and logic programming. Python is often referred to as a 'glue language' because it is purposely designed to be able to integrate components written in other languages. Python uses dynamic typing and a combination of reference counting and a cycle-detecting garbage collector for memory management. It uses dynamic name resolution (late binding), which binds method and variable names during program execution. Python's design offers some support for functional programming in the "Lisp tradition". It has filter, map, and reduce functions; list comprehensions, dictionaries, sets, and generator expressions. The standard library has two modules (itertools and functools) that implement functional tools borrowed from Haskell and Standard ML. Python's core philosophy is summarized in the Zen of Python (PEP 20) written by Tim Peters, which includes aphorisms such as these: However, Python has received criticism for violating these principles and adding unnecessary language bloat. Responses to these criticisms note that the Zen of Python is a guideline rather than a rule. The addition of some new features had been controversial: Guido van Rossum resigned as Benevolent Dictator for Life after conflict about adding the assignment expression operator in Python 3.8. Nevertheless, rather than building all functionality into its core, Python was designed to be highly extensible via modules. This compact modularity has made it particularly popular as a means of adding programmable interfaces to existing applications. Van Rossum's vision of a small core language with a large standard library and easily extensible interpreter stemmed from his frustrations with ABC, which represented the opposite approach. Python claims to strive for a simpler, less-cluttered syntax and grammar, while giving developers a choice in their coding methodology. Python lacks do .. while loops, which Rossum considered harmful. In contrast to Perl's motto "there is more than one way to do it", Python advocates an approach where "there should be one – and preferably only one – obvious way to do it". In practice, however, Python provides many ways to achieve a given goal. There are at least three ways to format a string literal, with no certainty as to which one a programmer should use. Alex Martelli is a Fellow at the Python Software Foundation and Python book author; he wrote that "To describe something as 'clever' is not considered a compliment in the Python culture." Python's developers typically prioritize readability over performance. For example, they reject patches to non-critical parts of the CPython reference implementation that would offer increases in speed that do not justify the cost of clarity and readability.[failed verification] Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as C, or by using a just-in-time compiler like PyPy. Also, it is possible to transpile to other languages. However, this approach either fails to achieve the expected speed-up, since Python is a very dynamic language, or only a restricted subset of Python is compiled (with potential minor semantic changes). Python is meant to be a fun language to use. This goal is reflected in the name – a tribute to the British comedy group Monty Python – and in playful approaches to some tutorials and reference materials. For instance, some code examples use the terms "spam" and "eggs" (in reference to a Monty Python sketch), rather than the typical terms "foo" and "bar". A common neologism in the Python community is pythonic, which has a broad range of meanings related to program style: Pythonic code may use Python idioms well; be natural or show fluency in the language; or conform with Python's minimalist philosophy and emphasis on readability. Syntax and semantics Python is meant to be an easily readable language. Its formatting is visually uncluttered and often uses English keywords where other languages use punctuation. Unlike many other languages, it does not use curly brackets to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than C or Pascal. Python uses whitespace indentation, rather than curly brackets or keywords, to delimit blocks. An increase in indentation comes after certain statements; a decrease in indentation signifies the end of the current block. Thus, the program's visual structure accurately represents its semantic structure. This feature is sometimes termed the off-side rule. Some other languages use indentation this way; but in most, indentation has no semantic meaning. The recommended indent size is four spaces. Python's statements include the following: The assignment statement (=) binds a name as a reference to a separate, dynamically allocated object. Variables may subsequently be rebound at any time to any object. In Python, a variable name is a generic reference holder without a fixed data type; however, it always refers to some object with a type. This is called dynamic typing—in contrast to statically-typed languages, where each variable may contain only a value of a certain type. Python does not support tail call optimization or first-class continuations; according to Van Rossum, the language never will. However, better support for coroutine-like functionality is provided by extending Python's generators. Before 2.5, generators were lazy iterators; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into a generator function; and from version 3.3, data can be passed through multiple stack levels. Python's expressions include the following: In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as Common Lisp, Scheme, or Ruby. This distinction leads to duplicating some functionality, for example: A statement cannot be part of an expression; because of this restriction, expressions such as list and dict comprehensions (and lambda expressions) cannot contain statements. As a particular case, an assignment statement such as a = 1 cannot be part of the conditional expression of a conditional statement. Python uses duck typing, and it has typed objects but untyped variable names. Type constraints are not checked at definition time; rather, operations on an object may fail at usage time, indicating that the object is not of an appropriate type. Despite being dynamically typed, Python is strongly typed, forbidding operations that are poorly defined (e.g., adding a number and a string) rather than quietly attempting to interpret them. Python allows programmers to define their own types using classes, most often for object-oriented programming. New instances of classes are constructed by calling the class, for example, SpamClass() or EggsClass()); the classes are instances of the metaclass type (which is an instance of itself), thereby allowing metaprogramming and reflection. Before version 3.0, Python had two kinds of classes, both using the same syntax: old-style and new-style. Current Python versions support the semantics of only the new style. Python supports optional type annotations. These annotations are not enforced by the language, but may be used by external tools such as mypy to catch errors. Python includes a module typing including several type names for type annotations. Also, mypy supports a Python compiler called mypyc, which leverages type annotations for optimization. 1.33333 frozenset() Python includes conventional symbols for arithmetic operators (+, -, *, /), the floor-division operator //, and the modulo operator %. (With the modulo operator, a remainder can be negative, e.g., 4 % -3 == -2.) Also, Python offers the ** symbol for exponentiation, e.g. 5**3 == 125 and 9**0.5 == 3.0. Also, it offers the matrix‑multiplication operator @ . These operators work as in traditional mathematics; with the same precedence rules, the infix operators + and - can also be unary, to represent positive and negative numbers respectively. Division between integers produces floating-point results. The behavior of division has changed significantly over time: In Python terms, the / operator represents true division (or simply division), while the // operator represents floor division. Before version 3.0, the / operator represents classic division. Rounding towards negative infinity, though a different method than in most languages, adds consistency to Python. For instance, this rounding implies that the equation (a + b)//b == a//b + 1 is always true. Also, the rounding implies that the equation b*(a//b) + a%b == a is valid for both positive and negative values of a. As expected, the result of a%b lies in the half-open interval [0, b), where b is a positive integer; however, maintaining the validity of the equation requires that the result must lie in the interval (b, 0] when b is negative. Python provides a round function for rounding a float to the nearest integer. For tie-breaking, Python 3 uses the round to even method: round(1.5) and round(2.5) both produce 2. Python versions before 3 used the round-away-from-zero method: round(0.5) is 1.0, and round(-0.5) is −1.0. Python allows Boolean expressions that contain multiple equality relations to be consistent with general usage in mathematics. For example, the expression a < b < c tests whether a is less than b and b is less than c. C-derived languages interpret this expression differently: in C, the expression would first evaluate a < b, resulting in 0 or 1, and that result would then be compared with c. Python uses arbitrary-precision arithmetic for all integer operations. The Decimal type/class in the decimal module provides decimal floating-point numbers to a pre-defined arbitrary precision with several rounding modes. The Fraction class in the fractions module provides arbitrary precision for rational numbers. Due to Python's extensive mathematics library and the third-party library NumPy, the language is frequently used for scientific scripting in tasks such as numerical data processing and manipulation. Functions are created in Python by using the def keyword. A function is defined similarly to how it is called, by first providing the function name and then the required parameters. Here is an example of a function that prints its inputs: To assign a default value to a function parameter in case no actual value is provided at run time, variable-definition syntax can be used inside the function header. Code examples "Hello, World!" program: Program to calculate the factorial of a non-negative integer: Libraries Python's large standard library is commonly cited as one of its greatest strengths. For Internet-facing applications, many standard formats and protocols such as MIME and HTTP are supported. The language includes modules for creating graphical user interfaces, connecting to relational databases, generating pseudorandom numbers, arithmetic with arbitrary-precision decimals, manipulating regular expressions, and unit testing. Some parts of the standard library are covered by specifications—for example, the Web Server Gateway Interface (WSGI) implementation wsgiref follows PEP 333—but most parts are specified by their code, internal documentation, and test suites. However, because most of the standard library is cross-platform Python code, only a few modules must be altered or rewritten for variant implementations. As of 13 March 2025,[update] the Python Package Index (PyPI), the official repository for third-party Python software, contains over 614,339 packages. Development environments Most[which?] Python implementations (including CPython) include a read–eval–print loop (REPL); this permits the environment to function as a command line interpreter, with which users enter statements sequentially and receive results immediately. Also, CPython is bundled with an integrated development environment (IDE) called IDLE, which is oriented toward beginners.[citation needed] Other shells, including IDLE and IPython, add additional capabilities such as improved auto-completion, session-state retention, and syntax highlighting. Standard desktop IDEs include PyCharm, Spyder, and Visual Studio Code; there are web browser-based IDEs, such as the following environments: Implementations CPython is the reference implementation of Python. This implementation is written in C, meeting the C11 standard since version 3.11. Older versions use the C89 standard with several select C99 features, but third-party extensions are not limited to older C versions—e.g., they can be implemented using C11 or C++. CPython compiles Python programs into an intermediate bytecode, which is then executed by a virtual machine. CPython is distributed with a large standard library written in a combination of C and native Python. CPython is available for many platforms, including Windows and most modern Unix-like systems, including macOS (and Apple M1 Macs, since Python 3.9.1, using an experimental installer). Starting with Python 3.9, the Python installer intentionally fails to install on Windows 7 and 8; Windows XP was supported until Python 3.5, with unofficial support for VMS. Platform portability was one of Python's earliest priorities. During development of Python 1 and 2, even OS/2 and Solaris were supported; since that time, support has been dropped for many platforms. All current Python versions (since 3.7) support only operating systems that feature multithreading, by now supporting not nearly as many operating systems (dropping many outdated) than in the past. All alternative implementations have at least slightly different semantics. For example, an alternative may include unordered dictionaries, in contrast to other current Python versions. As another example in the larger Python ecosystem, PyPy does not support the full C Python API. Creating an executable with Python often is done by bundling an entire Python interpreter into the executable, which causes binary sizes to be massive for small programs, yet there exist implementations that are capable of truly compiling Python. Alternative implementations include the following: Stackless Python is a significant fork of CPython that implements microthreads. This implementation uses the call stack differently, thus allowing massively concurrent programs. PyPy also offers a stackless version. Just-in-time Python compilers have been developed, but are now unsupported: There are several compilers/transpilers to high-level object languages; the source language is unrestricted Python, a subset of Python, or a language similar to Python: There are also specialized compilers: Some older projects existed, as well as compilers not designed for use with Python 3.x and related syntax: A performance comparison among various Python implementations, using a non-numerical (combinatorial) workload, was presented at EuroSciPy '13. In addition, Python's performance relative to other programming languages is benchmarked by The Computer Language Benchmarks Game. There are several approaches to optimizing Python performance, despite the inherent slowness of an interpreted language. These approaches include the following strategies or tools: Language Development Python's development is conducted mostly through the Python Enhancement Proposal (PEP) process; this process is the primary mechanism for proposing major new features, collecting community input on issues, and documenting Python design decisions. Python coding style is covered in PEP 8. Outstanding PEPs are reviewed and commented on by the Python community and the steering council. Enhancement of the language corresponds with development of the CPython reference implementation. The mailing list python-dev is the primary forum for the language's development. Specific issues were originally discussed in the Roundup bug tracker hosted by the foundation. In 2022, all issues and discussions were migrated to GitHub. Development originally took place on a self-hosted source-code repository running Mercurial, until Python moved to GitHub in January 2017. CPython's public releases have three types, distinguished by which part of the version number is incremented: Many alpha, beta, and release-candidates are also released as previews and for testing before final releases. Although there is a rough schedule for releases, they are often delayed if the code is not ready yet. Python's development team monitors the state of the code by running a large unit test suite during development. The major academic conference on Python is PyCon. Also, there are special Python mentoring programs, such as PyLadies. Naming Python's name is inspired by the British comedy group Monty Python, whom Python creator Guido van Rossum enjoyed while developing the language. Monty Python references appear frequently in Python code and culture; for example, the metasyntactic variables often used in Python literature are spam and eggs, rather than the traditional foo and bar. Also, the official Python documentation contains various references to Monty Python routines. Python users are sometimes referred to as "Pythonistas". Languages influenced by Python See also Notes References Further reading External links |
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Contents Black hole A black hole is an astronomical body so compact that its gravity prevents anything, including light, from escaping. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. The boundary of no escape is called the event horizon. In general relativity, a black hole's event horizon seals an object's fate but produces no locally detectable change when crossed. General relativity also predicts that every black hole should have a central singularity, where the curvature of spacetime is infinite. In many ways, a black hole acts like an ideal black body, as it reflects no light. Quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly. Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. In 1916, Karl Schwarzschild found the first modern solution of general relativity that would characterise a black hole. Due to his influential research, the Schwarzschild metric is named after him. David Finkelstein, in 1958, first interpreted Schwarzschild's model as a region of space from which nothing can escape. Black holes were long considered a mathematical curiosity; it was not until the 1960s that theoretical work showed they were a generic prediction of general relativity. The first black hole known was Cygnus X-1, identified by several researchers independently in 1971. Black holes typically form when massive stars collapse at the end of their life cycle. After a black hole has formed, it can grow by absorbing mass from its surroundings. Supermassive black holes of millions of solar masses may form by absorbing other stars and merging with other black holes, or via direct collapse of gas clouds. There is consensus that supermassive black holes exist in the centres of most galaxies. The presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Matter falling toward a black hole can form an accretion disk of infalling plasma, heated by friction and emitting light. In extreme cases, this creates a quasar, some of the brightest objects in the universe. Merging black holes can also be detected by observation of the gravitational waves they emit. If other stars are orbiting a black hole, their orbits can be used to determine the black hole's mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in binary systems and established that the radio source known as Sagittarius A*, at the core of the Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses. History The idea of a body so massive that even light could not escape was first proposed in the late 18th century by English astronomer and clergyman John Michell and independently by French scientist Pierre-Simon Laplace. Both scholars proposed very large stars in contrast to the modern concept of an extremely dense object. Michell's idea, in a short part of a letter published in 1784, calculated that a star with the same density but 500 times the radius of the sun would not let any emitted light escape; the surface escape velocity would exceed the speed of light.: 122 Michell correctly hypothesized that such supermassive but non-radiating bodies might be detectable through their gravitational effects on nearby visible bodies. In 1796, Laplace mentioned that a star could be invisible if it were sufficiently large while speculating on the origin of the Solar System in his book Exposition du Système du Monde. Franz Xaver von Zach asked Laplace for a mathematical analysis, which Laplace provided and published in a journal edited by von Zach. In 1905, Albert Einstein showed that the laws of electromagnetism would be invariant under a Lorentz transformation: they would be identical for observers travelling at different velocities relative to each other. This discovery became known as the principle of special relativity. Although the laws of mechanics had already been shown to be invariant, gravity remained yet to be included.: 19 In 1907, Einstein published a paper proposing his equivalence principle, the hypothesis that inertial mass and gravitational mass have a common cause. Using the principle, Einstein predicted the redshift and half of the lensing effect of gravity on light; the full prediction of gravitational lensing required development of general relativity.: 19 By 1915, Einstein refined these ideas into his general theory of relativity, which explained how matter affects spacetime, which in turn affects the motion of other matter. This formed the basis for black hole physics. Only a few months after Einstein published the field equations describing general relativity, astrophysicist Karl Schwarzschild set out to apply the idea to stars. He assumed spherical symmetry with no spin and found a solution to Einstein's equations.: 124 A few months after Schwarzschild, Johannes Droste, a student of Hendrik Lorentz, independently gave the same solution. At a certain radius from the center of the mass, the Schwarzschild solution became singular, meaning that some of the terms in the Einstein equations became infinite. The nature of this radius, which later became known as the Schwarzschild radius, was not understood at the time. Many physicists of the early 20th century were skeptical of the existence of black holes. In a 1926 popular science book, Arthur Eddington critiqued the idea of a star with mass compressed to its Schwarzschild radius as a flaw in the then-poorly-understood theory of general relativity.: 134 In 1939, Einstein himself used his theory of general relativity in an attempt to prove that black holes were impossible. His work relied on increasing pressure or increasing centrifugal force balancing the force of gravity so that the object would not collapse beyond its Schwarzschild radius. He missed the possibility that implosion would drive the system below this critical value.: 135 By the 1920s, astronomers had classified a number of white dwarf stars as too cool and dense to be explained by the gradual cooling of ordinary stars. In 1926, Ralph Fowler showed that quantum-mechanical degeneracy pressure was larger than thermal pressure at these densities.: 145 In 1931, Subrahmanyan Chandrasekhar calculated that a non-rotating body of electron-degenerate matter below a certain limiting mass is stable, and by 1934 he showed that this explained the catalog of white dwarf stars.: 151 When Chandrasekhar announced his results, Eddington pointed out that stars above this limit would radiate until they were sufficiently dense to prevent light from exiting, a conclusion he considered absurd. Eddington and, later, Lev Landau argued that some yet unknown mechanism would stop the collapse. In the 1930s, Fritz Zwicky and Walter Baade studied stellar novae, focusing on exceptionally bright ones they called supernovae. Zwicky promoted the idea that supernovae produced stars with the density of atomic nuclei—neutron stars—but this idea was largely ignored.: 171 In 1939, based on Chandrasekhar's reasoning, J. Robert Oppenheimer and George Volkoff predicted that neutron stars below a certain mass limit, later called the Tolman–Oppenheimer–Volkoff limit, would be stable due to neutron degeneracy pressure. Above that limit, they reasoned that either their model would not apply or that gravitational contraction would not stop.: 380 John Archibald Wheeler and two of his students resolved questions about the model behind the Tolman–Oppenheimer–Volkoff (TOV) limit. Harrison and Wheeler developed the equations of state relating density to pressure for cold matter all the way through electron degeneracy and neutron degeneracy. Masami Wakano and Wheeler then used the equations to compute the equilibrium curve for stars, relating mass to circumference. They found no additional features that would invalidate the TOV limit. This meant that the only thing that could prevent black holes from forming was a dynamic process ejecting sufficient mass from a star as it cooled.: 205 The modern concept of black holes was formulated by Robert Oppenheimer and his student Hartland Snyder in 1939.: 80 In the paper, Oppenheimer and Snyder solved Einstein's equations of general relativity for an idealized imploding star, in a model later called the Oppenheimer–Snyder model, then described the results from far outside the star. The implosion starts as one might expect: the star material rapidly collapses inward. However, as the density of the star increases, gravitational time dilation increases and the collapse, viewed from afar, seems to slow down further and further until the star reaches its Schwarzschild radius, where it appears frozen in time.: 217 In 1958, David Finkelstein identified the Schwarzschild surface as an event horizon, calling it "a perfect unidirectional membrane: causal influences can cross it in only one direction". In this sense, events that occur inside of the black hole cannot affect events that occur outside of the black hole. Finkelstein created a new reference frame to include the point of view of infalling observers.: 103 Finkelstein's new frame of reference allowed events at the surface of an imploding star to be related to events far away. By 1962 the two points of view were reconciled, convincing many skeptics that implosion into a black hole made physical sense.: 226 The era from the mid-1960s to the mid-1970s was the "golden age of black hole research", when general relativity and black holes became mainstream subjects of research.: 258 In this period, more general black hole solutions were found. In 1963, Roy Kerr found the exact solution for a rotating black hole. Two years later, Ezra Newman found the cylindrically symmetric solution for a black hole that is both rotating and electrically charged. In 1967, Werner Israel found that the Schwarzschild solution was the only possible solution for a nonspinning, uncharged black hole, meaning that a Schwarzschild black hole would be defined by its mass alone. Similar identities were later found for Reissner-Nordstrom and Kerr black holes, defined only by their mass and their charge or spin respectively. Together, these findings became known as the no-hair theorem, which states that a stationary black hole is completely described by the three parameters of the Kerr–Newman metric: mass, angular momentum, and electric charge. At first, it was suspected that the strange mathematical singularities found in each of the black hole solutions only appeared due to the assumption that a black hole would be perfectly spherically symmetric, and therefore the singularities would not appear in generic situations where black holes would not necessarily be symmetric. This view was held in particular by Vladimir Belinski, Isaak Khalatnikov, and Evgeny Lifshitz, who tried to prove that no singularities appear in generic solutions, although they would later reverse their positions. However, in 1965, Roger Penrose proved that general relativity without quantum mechanics requires that singularities appear in all black holes. Astronomical observations also made great strides during this era. In 1967, Antony Hewish and Jocelyn Bell Burnell discovered pulsars and by 1969, these were shown to be rapidly rotating neutron stars. Until that time, neutron stars, like black holes, were regarded as just theoretical curiosities, but the discovery of pulsars showed their physical relevance and spurred a further interest in all types of compact objects that might be formed by gravitational collapse. Based on observations in Greenwich and Toronto in the early 1970s, Cygnus X-1, a galactic X-ray source discovered in 1964, became the first astronomical object commonly accepted to be a black hole. Work by James Bardeen, Jacob Bekenstein, Carter, and Hawking in the early 1970s led to the formulation of black hole thermodynamics. These laws describe the behaviour of a black hole in close analogy to the laws of thermodynamics by relating mass to energy, area to entropy, and surface gravity to temperature. The analogy was completed: 442 when Hawking, in 1974, showed that quantum field theory implies that black holes should radiate like a black body with a temperature proportional to the surface gravity of the black hole, predicting the effect now known as Hawking radiation. While Cygnus X-1, a stellar-mass black hole, was generally accepted by the scientific community as a black hole by the end of 1973, it would be decades before a supermassive black hole would gain the same broad recognition. Although, as early as the 1960s, physicists such as Donald Lynden-Bell and Martin Rees had suggested that powerful quasars in the center of galaxies were powered by accreting supermassive black holes, little observational proof existed at the time. However, the Hubble Space Telescope, launched decades later, found that supermassive black holes were not only present in these active galactic nuclei, but that supermassive black holes in the center of galaxies were ubiquitous: Almost every galaxy had a supermassive black hole at its center, many of which were quiescent. In 1999, David Merritt proposed the M–sigma relation, which related the dispersion of the velocity of matter in the center bulge of a galaxy to the mass of the supermassive black hole at its core. Subsequent studies confirmed this correlation. Around the same time, based on telescope observations of the velocities of stars at the center of the Milky Way galaxy, independent work groups led by Andrea Ghez and Reinhard Genzel concluded that the compact radio source in the center of the galaxy, Sagittarius A*, was likely a supermassive black hole. On 11 February 2016, the LIGO Scientific Collaboration and Virgo Collaboration announced the first direct detection of gravitational waves, named GW150914, representing the first observation of a black hole merger. At the time of the merger, the black holes were approximately 1.4 billion light-years away from Earth and had masses of 30 and 35 solar masses.: 6 In 2017, Rainer Weiss, Kip Thorne, and Barry Barish, who had spearheaded the project, were awarded the Nobel Prize in Physics for their work. Since the initial discovery in 2015, hundreds more gravitational waves have been observed by LIGO and another interferometer, Virgo. On 10 April 2019, the first direct image of a black hole and its vicinity was published, following observations made by the Event Horizon Telescope (EHT) in 2017 of the supermassive black hole in Messier 87's galactic centre. In 2022, the Event Horizon Telescope collaboration released an image of the black hole in the center of the Milky Way galaxy, Sagittarius A*; The data had been collected in 2017. In 2020, the Nobel Prize in Physics was awarded for work on black holes. Andrea Ghez and Reinhard Genzel shared one-half for their discovery that Sagittarius A* is a supermassive black hole. Penrose received the other half for his work showing that the mathematics of general relativity requires the formation of black holes. Cosmologists lamented that Hawking's extensive theoretical work on black holes would not be honored since he died in 2018. In December 1967, a student reportedly suggested the phrase black hole at a lecture by John Wheeler; Wheeler adopted the term for its brevity and "advertising value", and Wheeler's stature in the field ensured it quickly caught on, leading some to credit Wheeler with coining the phrase. However, the term was used by others around that time. Science writer Marcia Bartusiak traces the term black hole to physicist Robert H. Dicke, who in the early 1960s reportedly compared the phenomenon to the Black Hole of Calcutta, notorious as a prison where people entered but never left alive. The term was used in print by Life and Science News magazines in 1963, and by science journalist Ann Ewing in her article "'Black Holes' in Space", dated 18 January 1964, which was a report on a meeting of the American Association for the Advancement of Science held in Cleveland, Ohio. Definition A black hole is generally defined as a region of spacetime from which no information-carrying signals or objects can escape. However, verifying an object as a black hole by this definition would require waiting for an infinite time and at an infinite distance from the black hole to verify that indeed, nothing has escaped, and thus cannot be used to identify a physical black hole. Broadly, physicists do not have a precisely-agreed-upon definition of a black hole. Among astrophysicists, a black hole is a compact object with a mass larger than four solar masses. A black hole may also be defined as a reservoir of information: 142 or a region where space is falling inwards faster than the speed of light. Properties The no-hair theorem postulates that, once it achieves a stable condition after formation, a black hole has only three independent physical properties: mass, electric charge, and angular momentum; the black hole is otherwise featureless. If the conjecture is true, any two black holes that share the same values for these properties, or parameters, are indistinguishable from one another. The degree to which the conjecture is true for real black holes is currently an unsolved problem. The simplest static black holes have mass but neither electric charge nor angular momentum. According to Birkhoff's theorem, these Schwarzschild black holes are the only vacuum solution that is spherically symmetric. Solutions describing more general black holes also exist. Non-rotating charged black holes are described by the Reissner–Nordström metric, while the Kerr metric describes a non-charged rotating black hole. The most general stationary black hole solution known is the Kerr–Newman metric, which describes a black hole with both charge and angular momentum. The simplest static black holes have mass but neither electric charge nor angular momentum. Contrary to the popular notion of a black hole "sucking in everything" in its surroundings, from far away, the external gravitational field of a black hole is identical to that of any other body of the same mass. While a black hole can theoretically have any positive mass, the charge and angular momentum are constrained by the mass. The total electric charge Q and the total angular momentum J are expected to satisfy the inequality Q 2 4 π ϵ 0 + c 2 J 2 G M 2 ≤ G M 2 {\displaystyle {\frac {Q^{2}}{4\pi \epsilon _{0}}}+{\frac {c^{2}J^{2}}{GM^{2}}}\leq GM^{2}} for a black hole of mass M. Black holes with the maximum possible charge or spin satisfying this inequality are called extremal black holes. Solutions of Einstein's equations that violate this inequality exist, but they do not possess an event horizon. These are so-called naked singularities that can be observed from the outside. Because these singularities make the universe inherently unpredictable, many physicists believe they could not exist. The weak cosmic censorship hypothesis, proposed by Sir Roger Penrose, rules out the formation of such singularities, when they are created through the gravitational collapse of realistic matter. However, this theory has not yet been proven, and some physicists believe that naked singularities could exist. It is also unknown whether black holes could even become extremal, forming naked singularities, since natural processes counteract increasing spin and charge when a black hole becomes near-extremal. The total mass of a black hole can be estimated by analyzing the motion of objects near the black hole, such as stars or gas. All black holes spin, often fast—One supermassive black hole, GRS 1915+105 has been estimated to spin at over 1,000 revolutions per second. The Milky Way's central black hole Sagittarius A* rotates at about 90% of the maximum rate. The spin rate can be inferred from measurements of atomic spectral lines in the X-ray range. As gas near the black hole plunges inward, high energy X-ray emission from electron-positron pairs illuminates the gas further out, appearing red-shifted due to relativistic effects. Depending on the spin of the black hole, this plunge happens at different radii from the hole, with different degrees of redshift. Astronomers can use the gap between the x-ray emission of the outer disk and the redshifted emission from plunging material to determine the spin of the black hole. A newer way to estimate spin is based on the temperature of gasses accreting onto the black hole. The method requires an independent measurement of the black hole mass and inclination angle of the accretion disk followed by computer modeling. Gravitational waves from coalescing binary black holes can also provide the spin of both progenitor black holes and the merged hole, but such events are rare. A spinning black hole has angular momentum. The supermassive black hole in the center of the Messier 87 (M87) galaxy appears to have an angular momentum very close to the maximum theoretical value. That uncharged limit is J ≤ G M 2 c , {\displaystyle J\leq {\frac {GM^{2}}{c}},} allowing definition of a dimensionless spin magnitude such that 0 ≤ c J G M 2 ≤ 1. {\displaystyle 0\leq {\frac {cJ}{GM^{2}}}\leq 1.} Most black holes are believed to have an approximately neutral charge. For example, Michal Zajaček, Arman Tursunov, Andreas Eckart, and Silke Britzen found the electric charge of Sagittarius A* to be at least ten orders of magnitude below the theoretical maximum. A charged black hole repels other like charges just like any other charged object. If a black hole were to become charged, particles with an opposite sign of charge would be pulled in by the extra electromagnetic force, while particles with the same sign of charge would be repelled, neutralizing the black hole. This effect may not be as strong if the black hole is also spinning. The presence of charge can reduce the diameter of the black hole by up to 38%. The charge Q for a nonspinning black hole is bounded by Q ≤ G M , {\displaystyle Q\leq {\sqrt {G}}M,} where G is the gravitational constant and M is the black hole's mass. Classification Black holes can have a wide range of masses. The minimum mass of a black hole formed by stellar gravitational collapse is governed by the maximum mass of a neutron star and is believed to be approximately two-to-four solar masses. However, theoretical primordial black holes, believed to have formed soon after the Big Bang, could be far smaller, with masses as little as 10−5 grams at formation. These very small black holes are sometimes called micro black holes. Black holes formed by stellar collapse are called stellar black holes. Estimates of their maximum mass at formation vary, but generally range from 10 to 100 solar masses, with higher estimates for black holes progenated by low-metallicity stars. The mass of a black hole formed via a supernova has a lower bound: If the progenitor star is too small, the collapse may be stopped by the degeneracy pressure of the star's constituents, allowing the condensation of matter into an exotic denser state. Degeneracy pressure occurs from the Pauli exclusion principle—Particles will resist being in the same place as each other. Smaller progenitor stars, with masses less than about 8 M☉, will be held together by the degeneracy pressure of electrons and will become a white dwarf. For more massive progenitor stars, electron degeneracy pressure is no longer strong enough to resist the force of gravity and the star will be held together by neutron degeneracy pressure, which can occur at much higher densities, forming a neutron star. If the star is still too massive, even neutron degeneracy pressure will not be able to resist the force of gravity and the star will collapse into a black hole.: 5.8 Stellar black holes can also gain mass via accretion of nearby matter, often from a companion object such as a star. Black holes that are larger than stellar black holes but smaller than supermassive black holes are called intermediate-mass black holes, with masses of approximately 102 to 105 solar masses. These black holes seem to be rarer than their stellar and supermassive counterparts, with relatively few candidates having been observed. Physicists have speculated that such black holes may form from collisions in globular and star clusters or at the center of low-mass galaxies. They may also form as the result of mergers of smaller black holes, with several LIGO observations finding merged black holes within the 110-350 solar mass range. The black holes with the largest masses are called supermassive black holes, with masses more than 106 times that of the Sun. These black holes are believed to exist at the centers of almost every large galaxy, including the Milky Way. Some scientists have proposed a subcategory of even larger black holes, called ultramassive black holes, with masses greater than 109-1010 solar masses. Theoretical models predict that the accretion disc that feeds black holes will be unstable once a black hole reaches 50-100 billion times the mass of the Sun, setting a rough upper limit to black hole mass. Structure While black holes are conceptually invisible sinks of all matter and light, in astronomical settings, their enormous gravity alters the motion of surrounding objects and pulls nearby gas inwards at near-light speed, making the area around black holes the brightest objects in the universe. Some black holes have relativistic jets—thin streams of plasma travelling away from the black hole at more than one-tenth of the speed of light. A small faction of the matter falling towards the black hole gets accelerated away along the hole rotation axis. These jets can extend as far as millions of parsecs from the black hole itself. Black holes of any mass can have jets. However, they are typically observed around spinning black holes with strongly-magnetized accretion disks. Relativistic jets were more common in the early universe, when galaxies and their corresponding supermassive black holes were rapidly gaining mass. All black holes with jets also have an accretion disk, but the jets are usually brighter than the disk. Quasars, typically found in other galaxies, are believed to be supermassive black holes with jets; microquasars are believed to be stellar-mass objects with jets, typically observed in the Milky Way. The mechanism of formation of jets is not yet known, but several options have been proposed. One method proposed to fuel these jets is the Blandford-Znajek process, which suggests that the dragging of magnetic field lines by a black hole's rotation could launch jets of matter into space. The Penrose process, which involves extraction of a black hole's rotational energy, has also been proposed as a potential mechanism of jet propulsion. Due to conservation of angular momentum, gas falling into the gravitational well created by a massive object will typically form a disk-like structure around the object.: 242 As the disk's angular momentum is transferred outward due to internal processes, its matter falls farther inward, converting its gravitational energy into heat and releasing a large flux of x-rays. The temperature of these disks can range from thousands to millions of Kelvin, and temperatures can differ throughout a single accretion disk. Accretion disks can also emit in other parts of the electromagnetic spectrum, depending on the disk's turbulence and magnetization and the black hole's mass and angular momentum. Accretion disks can be defined as geometrically thin or geometrically thick. Geometrically thin disks are mostly confined to the black hole's equatorial plane and have a well-defined edge at the innermost stable circular orbit (ISCO), while geometrically thick disks are supported by internal pressure and temperature and can extend inside the ISCO. Disks with high rates of electron scattering and absorption, appearing bright and opaque, are called optically thick; optically thin disks are more translucent and produce fainter images when viewed from afar. Accretion disks of black holes accreting beyond the Eddington limit are often referred to as polish donuts due to their thick, toroidal shape that resembles that of a donut. Quasar accretion disks are expected to usually appear blue in color. The disk for a stellar black hole, on the other hand, would likely look orange, yellow, or red, with its inner regions being the brightest. Theoretical research suggests that the hotter a disk is, the bluer it should be, although this is not always supported by observations of real astronomical objects. Accretion disk colors may also be altered by the Doppler effect, with the part of the disk travelling towards an observer appearing bluer and brighter and the part of the disk travelling away from the observer appearing redder and dimmer. In Newtonian gravity, test particles can stably orbit at arbitrary distances from a central object. In general relativity, however, there exists a smallest possible radius for which a massive particle can orbit stably. Any infinitesimal inward perturbations to this orbit will lead to the particle spiraling into the black hole, and any outward perturbations will, depending on the energy, cause the particle to spiral in, move to a stable orbit further from the black hole, or escape to infinity. This orbit is called the innermost stable circular orbit, or ISCO. The location of the ISCO depends on the spin of the black hole and the spin of the particle itself. In the case of a Schwarzschild black hole (spin zero) and a particle without spin, the location of the ISCO is: r I S C O = 3 r s = 6 G M c 2 , {\displaystyle r_{\rm {ISCO}}=3\,r_{\text{s}}={\frac {6\,GM}{c^{2}}},} where r I S C O {\displaystyle r_{\rm {_{ISCO}}}} is the radius of the ISCO, r s {\displaystyle r_{\text{s}}} is the Schwarzschild radius of the black hole, G {\displaystyle G} is the gravitational constant, and c {\displaystyle c} is the speed of light. The radius of this orbit changes slightly based on particle spin. For charged black holes, the ISCO moves inwards. For spinning black holes, the ISCO is moved inwards for particles orbiting in the same direction that the black hole is spinning (prograde) and outwards for particles orbiting in the opposite direction (retrograde). For example, the ISCO for a particle orbiting retrograde can be as far out as about 9 r s {\displaystyle 9r_{\text{s}}} , while the ISCO for a particle orbiting prograde can be as close as at the event horizon itself. The photon sphere is a spherical boundary for which photons moving on tangents to that sphere are bent completely around the black hole, possibly orbiting multiple times. Light rays with impact parameters less than the radius of the photon sphere enter the black hole. For Schwarzschild black holes, the photon sphere has a radius 1.5 times the Schwarzschild radius; the radius for non-Schwarzschild black holes is at least 1.5 times the radius of the event horizon. When viewed from a great distance, the photon sphere creates an observable black hole shadow. Since no light emerges from within the black hole, this shadow is the limit for possible observations.: 152 The shadow of colliding black holes should have characteristic warped shapes, allowing scientists to detect black holes that are about to merge. While light can still escape from the photon sphere, any light that crosses the photon sphere on an inbound trajectory will be captured by the black hole. Therefore, any light that reaches an outside observer from the photon sphere must have been emitted by objects between the photon sphere and the event horizon. Light emitted towards the photon sphere may also curve around the black hole and return to the emitter. For a rotating, uncharged black hole, the radius of the photon sphere depends on the spin parameter and whether the photon is orbiting prograde or retrograde. For a photon orbiting prograde, the photon sphere will be 1-3 Schwarzschild radii from the center of the black hole, while for a photon orbiting retrograde, the photon sphere will be between 3-5 Schwarzschild radii from the center of the black hole. The exact location of the photon sphere depends on the magnitude of the black hole's rotation. For a charged, nonrotating black hole, there will only be one photon sphere, and the radius of the photon sphere will decrease for increasing black hole charge. For non-extremal, charged, rotating black holes, there will always be two photon spheres, with the exact radii depending on the parameters of the black hole. Near a rotating black hole, spacetime rotates similar to a vortex. The rotating spacetime will drag any matter and light into rotation around the spinning black hole. This effect of general relativity, called frame dragging, gets stronger closer to the spinning mass. The region of spacetime in which it is impossible to stay still is called the ergosphere. The ergosphere of a black hole is a volume bounded by the black hole's event horizon and the ergosurface, which coincides with the event horizon at the poles but bulges out from it around the equator. Matter and radiation can escape from the ergosphere. Through the Penrose process, objects can emerge from the ergosphere with more energy than they entered with. The extra energy is taken from the rotational energy of the black hole, slowing down the rotation of the black hole.: 268 A variation of the Penrose process in the presence of strong magnetic fields, the Blandford–Znajek process, is considered a likely mechanism for the enormous luminosity and relativistic jets of quasars and other active galactic nuclei. The observable region of spacetime around a black hole closest to its event horizon is called the plunging region. In this area it is no longer possible for free falling matter to follow circular orbits or stop a final descent into the black hole. Instead, it will rapidly plunge toward the black hole at close to the speed of light, growing increasingly hot and producing a characteristic, detectable thermal emission. However, light and radiation emitted from this region can still escape from the black hole's gravitational pull. For a nonspinning, uncharged black hole, the radius of the event horizon, or Schwarzschild radius, is proportional to the mass, M, through r s = 2 G M c 2 ≈ 2.95 M M ⊙ k m , {\displaystyle r_{\mathrm {s} }={\frac {2GM}{c^{2}}}\approx 2.95\,{\frac {M}{M_{\odot }}}~\mathrm {km,} } where rs is the Schwarzschild radius and M☉ is the mass of the Sun.: 124 For a black hole with nonzero spin or electric charge, the radius is smaller,[Note 1] until an extremal black hole could have an event horizon close to r + = G M c 2 , {\displaystyle r_{\mathrm {+} }={\frac {GM}{c^{2}}},} half the radius of a nonspinning, uncharged black hole of the same mass. Since the volume within the Schwarzschild radius increase with the cube of the radius, average density of a black hole inside its Schwarzschild radius is inversely proportional to the square of its mass: supermassive black holes are much less dense than stellar black holes. The average density of a 108 M☉ black hole is comparable to that of water. The defining feature of a black hole is the existence of an event horizon, a boundary in spacetime through which matter and light can pass only inward towards the center of the black hole. Nothing, not even light, can escape from inside the event horizon. The event horizon is referred to as such because if an event occurs within the boundary, information from that event cannot reach or affect an outside observer, making it impossible to determine whether such an event occurred.: 179 For non-rotating black holes, the geometry of the event horizon is precisely spherical, while for rotating black holes, the event horizon is oblate. To a distant observer, a clock near a black hole would appear to tick more slowly than one further from the black hole.: 217 This effect, known as gravitational time dilation, would also cause an object falling into a black hole to appear to slow as it approached the event horizon, never quite reaching the horizon from the perspective of an outside observer.: 218 All processes on this object would appear to slow down, and any light emitted by the object to appear redder and dimmer, an effect known as gravitational redshift. An object falling from half of a Schwarzschild radius above the event horizon would fade away until it could no longer be seen, disappearing from view within one hundredth of a second. It would also appear to flatten onto the black hole, joining all other material that had ever fallen into the hole. On the other hand, an observer falling into a black hole would not notice any of these effects as they cross the event horizon. Their own clocks appear to them to tick normally, and they cross the event horizon after a finite time without noting any singular behaviour. In general relativity, it is impossible to determine the location of the event horizon from local observations, due to Einstein's equivalence principle.: 222 Black holes that are rotating and/or charged have an inner horizon, often called the Cauchy horizon, inside of the black hole. The inner horizon is divided up into two segments: an ingoing section and an outgoing section. At the ingoing section of the Cauchy horizon, radiation and matter that fall into the black hole would build up at the horizon, causing the curvature of spacetime to go to infinity. This would cause an observer falling in to experience tidal forces. This phenomenon is often called mass inflation, since it is associated with a parameter dictating the black hole's internal mass growing exponentially, and the buildup of tidal forces is called the mass-inflation singularity or Cauchy horizon singularity. Some physicists have argued that in realistic black holes, accretion and Hawking radiation would stop mass inflation from occurring. At the outgoing section of the inner horizon, infalling radiation would backscatter off of the black hole's spacetime curvature and travel outward, building up at the outgoing Cauchy horizon. This would cause an infalling observer to experience a gravitational shock wave and tidal forces as the spacetime curvature at the horizon grew to infinity. This buildup of tidal forces is called the shock singularity. Both of these singularities are weak, meaning that an object crossing them would only be deformed a finite amount by tidal forces, even though the spacetime curvature would still be infinite at the singularity. This is as opposed to a strong singularity, where an object hitting the singularity would be stretched and squeezed by an infinite amount. They are also null singularities, meaning that a photon could travel parallel to the them without ever being intercepted. Ignoring quantum effects, every black hole has a singularity inside, points where the curvature of spacetime becomes infinite, and geodesics terminate within a finite proper time.: 205 For a non-rotating black hole, this region takes the shape of a single point; for a rotating black hole it is smeared out to form a ring singularity that lies in the plane of rotation.: 264 In both cases, the singular region has zero volume. All of the mass of the black hole ends up in the singularity.: 252 Since the singularity has nonzero mass in an infinitely small space, it can be thought of as having infinite density. Observers falling into a Schwarzschild black hole (i.e., non-rotating and not charged) cannot avoid being carried into the singularity once they cross the event horizon. As they fall further into the black hole, they will be torn apart by the growing tidal forces in a process sometimes referred to as spaghettification or the noodle effect. Eventually, they will reach the singularity and be crushed into an infinitely small point.: 182 However any perturbations, such as those caused by matter or radiation falling in, would cause space to oscillate chaotically near the singularity. Any matter falling in would experience intense tidal forces rapidly changing in direction, all while being compressed into an increasingly small volume. Alternative forms of general relativity, including addition of some quatum effects, can lead to regular, or nonsingular, black holes without singularities. For example, the fuzzball model, based on string theory, states that black holes are actually made up of quantum microstates and need not have a singularity or an event horizon. The theory of loop quantum gravity proposes that the curvature and density at the center of a black hole is large, but not infinite. Formation Black holes are formed by gravitational collapse of massive stars, either by direct collapse or during a supernova explosion in a process called fallback. Black holes can result from the merger of two neutron stars or a neutron star and a black hole. Other more speculative mechanisms include primordial black holes created from density fluctuations in the early universe, the collapse of dark stars, a hypothetical object powered by annihilation of dark matter, or from hypothetical self-interacting dark matter. Gravitational collapse occurs when an object's internal pressure is insufficient to resist the object's own gravity. At the end of a star's life, it will run out of hydrogen to fuse, and will start fusing more and more massive elements, until it gets to iron. Since the fusion of elements heavier than iron would require more energy than it would release, nuclear fusion ceases. If the iron core of the star is too massive, the star will no longer be able to support itself and will undergo gravitational collapse. While most of the energy released during gravitational collapse is emitted very quickly, an outside observer does not actually see the end of this process. Even though the collapse takes a finite amount of time from the reference frame of infalling matter, a distant observer would see the infalling material slow and halt just above the event horizon, due to gravitational time dilation. Light from the collapsing material takes longer and longer to reach the observer, with the delay growing to infinity as the emitting material reaches the event horizon. Thus the external observer never sees the formation of the event horizon; instead, the collapsing material seems to become dimmer and increasingly red-shifted, eventually fading away. Observations of quasars at redshift z ∼ 7 {\displaystyle z\sim 7} , less than a billion years after the Big Bang, has led to investigations of other ways to form black holes. The accretion process to build supermassive black holes has a limiting rate of mass accumulation and a billion years is not enough time to reach quasar status. One suggestion is direct collapse of nearly pure hydrogen gas (low metalicity) clouds characteristic of the young universe, forming a supermassive star which collapses into a black hole. It has been suggested that seed black holes with typical masses of ~105 M☉ could have formed in this way which then could grow to ~109 M☉. However, the very large amount of gas required for direct collapse is not typically stable to fragmentation to form multiple stars. Thus another approach suggests massive star formation followed by collisions that seed massive black holes which ultimately merge to create a quasar.: 85 A neutron star in a common envelope with a regular star can accrete sufficient material to collapse to a black hole or two neutron stars can merge. These avenues for the formation of black holes are considered relatively rare. In the current epoch of the universe, conditions needed to form black holes are rare and are mostly only found in stars. However, in the early universe, conditions may have allowed for black hole formations via other means. Fluctuations of spacetime soon after the Big Bang may have formed areas that were denser then their surroundings. Initially, these regions would not have been compact enough to form a black hole, but eventually, the curvature of spacetime in the regions become large enough to cause them to collapse into a black hole. Different models for the early universe vary widely in their predictions of the scale of these fluctuations. Various models predict the creation of primordial black holes ranging from a Planck mass (~2.2×10−8 kg) to hundreds of thousands of solar masses. Primordial black holes with masses less than 1015 g would have evaporated by now due to Hawking radiation. Despite the early universe being extremely dense, it did not re-collapse into a black hole during the Big Bang, since the universe was expanding rapidly and did not have the gravitational differential necessary for black hole formation. Models for the gravitational collapse of objects of relatively constant size, such as stars, do not necessarily apply in the same way to rapidly expanding space such as the Big Bang. In principle, black holes could be formed in high-energy particle collisions that achieve sufficient density, although no such events have been detected. These hypothetical micro black holes, which could form from the collision of cosmic rays and Earth's atmosphere or in particle accelerators like the Large Hadron Collider, would not be able to aggregate additional mass. Instead, they would evaporate in about 10−25 seconds, posing no threat to the Earth. Evolution Black holes can also merge with other objects such as stars or even other black holes. This is thought to have been important, especially in the early growth of supermassive black holes, which could have formed from the aggregation of many smaller objects. The process has also been proposed as the origin of some intermediate-mass black holes. Mergers of supermassive black holes may take a long time: As a binary of supermassive black holes approach each other, most nearby stars are ejected, leaving little for the remaining black holes to gravitationally interact with that would allow them to get closer to each other. This phenomenon has been called the final parsec problem, as the distance at which this happens is usually around one parsec. When a black hole accretes matter, the gas in the inner accretion disk orbits at very high speeds because of its proximity to the black hole. The resulting friction heats the inner disk to temperatures at which it emits vast amounts of electromagnetic radiation (mainly X-rays) detectable by telescopes. By the time the matter of the disk reaches the ISCO, between 5.7% and 42% of its mass will have been converted to energy, depending on the black hole's spin. About 90% of this energy is released within about 20 black hole radii. In many cases, accretion disks are accompanied by relativistic jets that are emitted along the black hole's poles, which carry away much of the energy. The mechanism for the creation of these jets is currently not well understood, in part due to insufficient data. Many of the universe's most energetic phenomena have been attributed to the accretion of matter on black holes. Active galactic nuclei and quasars are believed to be the accretion disks of supermassive black holes. X-ray binaries are generally accepted to be binary systems in which one of the two objects is a compact object accreting matter from its companion. Ultraluminous X-ray sources may be the accretion disks of intermediate-mass black holes. At a certain rate of accretion, the outward radiation pressure will become as strong as the inward gravitational force, and the black hole should unable to accrete any faster. This limit is called the Eddington limit. However, many black holes accrete beyond this rate due to their non-spherical geometry or instabilities in the accretion disk. Accretion beyond the limit is called Super-Eddington accretion and may have been commonplace in the early universe. Stars have been observed to get torn apart by tidal forces in the immediate vicinity of supermassive black holes in galaxy nuclei, in what is known as a tidal disruption event (TDE). Some of the material from the disrupted star forms an accretion disk around the black hole, which emits observable electromagnetic radiation. The correlation between the masses of supermassive black holes in the centres of galaxies with the velocity dispersion and mass of stars in their host bulges suggests that the formation of galaxies and the formation of their central black holes are related. Black hole winds from rapid accretion, particularly when the galaxy itself is still accreting matter, can compress gas nearby, accelerating star formation. However, if the winds become too strong, the black hole may blow nearly all of the gas out of the galaxy, quenching star formation. Black hole jets may also energize nearby cavities of plasma and eject low-entropy gas from out of the galactic core, causing gas in galactic centers to be hotter than expected. If Hawking's theory of black hole radiation is correct, then black holes are expected to shrink and evaporate over time as they lose mass by the emission of photons and other particles. The temperature of this thermal spectrum (Hawking temperature) is proportional to the surface gravity of the black hole, which is inversely proportional to the mass. Hence, large black holes emit less radiation than small black holes.: Ch. 9.6 A stellar black hole of 1 M☉ has a Hawking temperature of 62 nanokelvins. This is far less than the 2.7 K temperature of the cosmic microwave background radiation. Stellar-mass or larger black holes receive more mass from the cosmic microwave background than they emit through Hawking radiation and thus will grow instead of shrinking. To have a Hawking temperature larger than 2.7 K (and be able to evaporate), a black hole would need a mass less than the Moon. Such a black hole would have a diameter of less than a tenth of a millimetre. The Hawking radiation for an astrophysical black hole is predicted to be very weak and would thus be exceedingly difficult to detect from Earth. A possible exception is the burst of gamma rays emitted in the last stage of the evaporation of primordial black holes. Searches for such flashes have proven unsuccessful and provide stringent limits on the possibility of existence of low mass primordial black holes, with modern research predicting that primordial black holes must make up less than a fraction of 10−7 of the universe's total mass. NASA's Fermi Gamma-ray Space Telescope, launched in 2008, has searched for these flashes, but has not yet found any. The properties of a black hole are constrained and interrelated by the theories that predict these properties. When based on general relativity, these relationships are called the laws of black hole mechanics. For a black hole that is not still forming or accreting matter, the zeroth law of black hole mechanics states the black hole's surface gravity is constant across the event horizon. The first law relates changes in the black hole's surface area, angular momentum, and charge to changes in its energy. The second law says the surface area of a black hole never decreases on its own. Finally, the third law says that the surface gravity of a black hole is never zero. These laws are mathematical analogs of the laws of thermodynamics. They are not equivalent, however, because, according to general relativity without quantum mechanics, a black hole can never emit radiation, and thus its temperature must always be zero.: 11 Quantum mechanics predicts that a black hole will continuously emit thermal Hawking radiation, and therefore must always have a nonzero temperature. It also predicts that all black holes have entropy which scales with their surface area. When quantum mechanics is accounted for, the laws of black hole mechanics become equivalent to the classical laws of thermodynamics. However, these conclusions are derived without a complete theory of quantum gravity, although many potential theories do predict black holes having entropy and temperature. Thus, the true quantum nature of black hole thermodynamics continues to be debated.: 29 Observational evidence Millions of black holes with around 30 solar masses derived from stellar collapse are expected to exist in the Milky Way. Even a dwarf galaxy like Draco should have hundreds. Only a few of these have been detected. By nature, black holes do not themselves emit any electromagnetic radiation other than the hypothetical Hawking radiation, so astrophysicists searching for black holes must generally rely on indirect observations. The defining characteristic of a black hole is its event horizon. The horizon itself cannot be imaged, so all other possible explanations for these indirect observations must be considered and eliminated before concluding that a black hole has been observed.: 11 The Event Horizon Telescope (EHT) is a global system of radio telescopes capable of directly observing a black hole shadow. The angular resolution of a telescope is based on its aperture and the wavelengths it is observing. Because the angular diameters of Sagittarius A* and Messier 87* in the sky are very small, a single telescope would need to be about the size of the Earth to clearly distinguish their horizons using radio wavelengths. By combining data from several different radio telescopes around the world, the Event Horizon Telescope creates an effective aperture the diameter size of the Earth. The EHT team used imaging algorithms to compute the most probable image from the data in its observations of Sagittarius A* and M87*. Gravitational-wave interferometry can be used to detect merging black holes and other compact objects. In this method, a laser beam is split down two long arms of a tunnel. The laser beams reflect off of mirrors in the tunnels and converge at the intersection of the arms, cancelling each other out. However, when a gravitational wave passes, it warps spacetime, changing the lengths of the arms themselves. Since each laser beam is now travelling a slightly different distance, they do not cancel out and produce a recognizable signal. Analysis of the signal can give scientists information about what caused the gravitational waves. Since gravitational waves are very weak, gravitational-wave observatories such as LIGO must have arms several kilometers long and carefully control for noise from Earth to be able to detect these gravitational waves. Since the first measurements in 2016, multiple gravitational waves from black holes have been detected and analyzed. The proper motions of stars near the centre of the Milky Way provide strong observational evidence that these stars are orbiting a supermassive black hole. Since 1995, astronomers have tracked the motions of 90 stars orbiting an invisible object coincident with the radio source Sagittarius A*. In 1998, by fitting the motions of the stars to Keplerian orbits, the astronomers were able to infer that Sagittarius A* must be a 2.6×106 M☉ object must be contained within a radius of 0.02 light-years. Since then, one of the stars—called S2—has completed a full orbit. From the orbital data, astronomers were able to refine the calculations of the mass of Sagittarius A* to 4.3×106 M☉, with a radius of less than 0.002 light-years. This upper limit radius is larger than the Schwarzschild radius for the estimated mass, so the combination does not prove Sagittarius A* is a black hole. Nevertheless, these observations strongly suggest that the central object is a supermassive black hole as there are no other plausible scenarios for confining so much invisible mass into such a small volume. Additionally, there is some observational evidence that this object might possess an event horizon, a feature unique to black holes. The Event Horizon Telescope image of Sagittarius A*, released in 2022, provided further confirmation that it is indeed a black hole. X-ray binaries are binary systems that emit a majority of their radiation in the X-ray part of the electromagnetic spectrum. These X-ray emissions result when a compact object accretes matter from an ordinary star. The presence of an ordinary star in such a system provides an opportunity for studying the central object and to determine if it might be a black hole. By measuring the orbital period of the binary, the distance to the binary from Earth, and the mass of the companion star, scientists can estimate the mass of the compact object. The Tolman-Oppenheimer-Volkoff limit (TOV limit) dictates the largest mass a nonrotating neutron star can be, and is estimated to be about two solar masses. While a rotating neutron star can be slightly more massive, if the compact object is much more massive than the TOV limit, it cannot be a neutron star and is generally expected to be a black hole. The first strong candidate for a black hole, Cygnus X-1, was discovered in this way by Charles Thomas Bolton, Louise Webster, and Paul Murdin in 1972. Observations of rotation broadening of the optical star reported in 1986 lead to a compact object mass estimate of 16 solar masses, with 7 solar masses as the lower bound. In 2011, this estimate was updated to 14.1±1.0 M☉ for the black hole and 19.2±1.9 M☉ for the optical stellar companion. X-ray binaries can be categorized as either low-mass or high-mass; This classification is based on the mass of the companion star, not the compact object itself. In a class of X-ray binaries called soft X-ray transients, the companion star is of relatively low mass, allowing for more accurate estimates of the black hole mass. These systems actively emit X-rays for only several months once every 10–50 years. During the period of low X-ray emission, called quiescence, the accretion disk is extremely faint, allowing detailed observation of the companion star. Numerous black hole candidates have been measured by this method. Black holes are also sometimes found in binaries with other compact objects, such as white dwarfs, neutron stars, and other black holes. The centre of nearly every galaxy contains a supermassive black hole. The close observational correlation between the mass of this hole and the velocity dispersion of the host galaxy's bulge, known as the M–sigma relation, strongly suggests a connection between the formation of the black hole and that of the galaxy itself. Astronomers use the term active galaxy to describe galaxies with unusual characteristics, such as unusual spectral line emission and very strong radio emission. Theoretical and observational studies have shown that the high levels of activity in the centers of these galaxies, regions called active galactic nuclei (AGN), may be explained by accretion onto supermassive black holes. These AGN consist of a central black hole that may be millions or billions of times more massive than the Sun, a disk of interstellar gas and dust called an accretion disk, and two jets perpendicular to the accretion disk. Although supermassive black holes are expected to be found in most AGN, only some galaxies' nuclei have been more carefully studied in attempts to both identify and measure the actual masses of the central supermassive black hole candidates. Some of the most notable galaxies with supermassive black hole candidates include the Andromeda Galaxy, Messier 32, Messier 87, the Sombrero Galaxy, and the Milky Way itself. Another way black holes can be detected is through observation of effects caused by their strong gravitational field. One such effect is gravitational lensing: The deformation of spacetime around a massive object causes light rays to be deflected, making objects behind them appear distorted. When the lensing object is a black hole, this effect can be strong enough to create multiple images of a star or other luminous source. However, the distance between the lensed images may be too small for contemporary telescopes to resolve—this phenomenon is called microlensing. Instead of seeing two images of a lensed star, astronomers see the star brighten slightly as the black hole moves towards the line of sight between the star and Earth and then return to its normal luminosity as the black hole moves away. The turn of the millennium saw the first 3 candidate detections of black holes in this way, and in January 2022, astronomers reported the first confirmed detection of a microlensing event from an isolated black hole. This was also the first determination of an isolated black hole mass, 7.1±1.3 M☉. Alternatives While there is a strong case for supermassive black holes, the model for stellar-mass black holes assumes of an upper limit for the mass of a neutron star: objects observed to have more mass are assumed to be black holes. However, the properties of extremely dense matter are poorly understood. New exotic phases of matter could allow other kinds of massive objects. Quark stars would be made up of quark matter and supported by quark degeneracy pressure, a form of degeneracy pressure even stronger than neutron degeneracy pressure. This would halt gravitational collapse at a higher mass than for a neutron star. Even stronger stars called electroweak stars would convert quarks in their cores into leptons, providing additional pressure to stop the star from collapsing. If, as some extensions of the Standard Model posit, quarks and leptons are made up of the even-smaller fundamental particles called preons, a very compact star could be supported by preon degeneracy pressure. While none of these hypothetical models can explain all of the observations of stellar black hole candidates, a Q star is the only alternative which could significantly exceed the mass limit for neutron stars and thus provide an alternative for supermassive black holes.: 12 A few theoretical objects have been conjectured to match observations of astronomical black hole candidates identically or near-identically, but which function via a different mechanism. A dark energy star would convert infalling matter into vacuum energy; This vacuum energy would be much larger than the vacuum energy of outside space, exerting outwards pressure and preventing a singularity from forming. A black star would be gravitationally collapsing slowly enough that quantum effects would keep it just on the cusp of fully collapsing into a black hole. A gravastar would consist of a very thin shell and a dark-energy interior providing outward pressure to stop the collapse into a black hole or formation of a singularity; It could even have another gravastar inside, called a 'nestar'. Open questions According to the no-hair theorem, a black hole is defined by only three parameters: its mass, charge, and angular momentum. This seems to mean that all other information about the matter that went into forming the black hole is lost, as there is no way to determine anything about the black hole from outside other than those three parameters. When black holes were thought to persist forever, this information loss was not problematic, as the information can be thought of as existing inside the black hole. However, black holes slowly evaporate by emitting Hawking radiation. This radiation does not appear to carry any additional information about the matter that formed the black hole, meaning that this information is seemingly gone forever. This is called the black hole information paradox. Theoretical studies analyzing the paradox have led to both further paradoxes and new ideas about the intersection of quantum mechanics and general relativity. While there is no consensus on the resolution of the paradox, work on the problem is expected to be important for a theory of quantum gravity.: 126 Observations of faraway galaxies have found that ultraluminous quasars, powered by supermassive black holes, existed in the early universe as far as redshift z ≥ 7 {\displaystyle z\geq 7} . These black holes have been assumed to be the products of the gravitational collapse of large population III stars. However, these stellar remnants were not massive enough to produce the quasars observed at early times without accreting beyond the Eddington limit, the theoretical maximum rate of black hole accretion. Physicists have suggested a variety of different mechanisms by which these supermassive black holes may have formed. It has been proposed that smaller black holes may have also undergone mergers to produce the observed supermassive black holes. It is also possible that they were seeded by direct-collapse black holes, in which a large cloud of hot gas avoids fragmentation that would lead to multiple stars, due to low angular momentum or heating from a nearby galaxy. Given the right circumstances, a single supermassive star forms and collapses directly into a black hole without undergoing typical stellar evolution. Additionally, these supermassive black holes in the early universe may be high-mass primordial black holes, which could have accreted further matter in the centers of galaxies. Finally, certain mechanisms allow black holes to grow faster than the theoretical Eddington limit, such as dense gas in the accretion disk limiting outward radiation pressure that prevents the black hole from accreting. However, the formation of bipolar jets prevent super-Eddington rates. In fiction Black holes have been portrayed in science fiction in a variety of ways. Even before the advent of the term itself, objects with characteristics of black holes appeared in stories such as the 1928 novel The Skylark of Space with its "black Sun" and the "hole in space" in the 1935 short story Starship Invincible. As black holes grew to public recognition in the 1960s and 1970s, they began to be featured in films as well as novels, such as Disney's The Black Hole. Black holes have also been used in works of the 21st century, such as Christopher Nolan's science fiction epic Interstellar. Authors and screenwriters have exploited the relativistic effects of black holes, particularly gravitational time dilation. For example, Interstellar features a black hole planet with a time dilation factor of over 60,000:1, while the 1977 novel Gateway depicts a spaceship approaching but never crossing the event horizon of a black hole from the perspective of an outside observer due to time dilation effects. Black holes have also been appropriated as wormholes or other methods of faster-than-light travel, such as in the 1974 novel The Forever War, where a network of black holes is used for interstellar travel. Additionally, black holes can feature as hazards to spacefarers and planets: A black hole threatens a deep-space outpost in 1978 short story The Black Hole Passes, and a binary black hole dangerously alters the orbit of a planet in the 2018 Netflix reboot of Lost in Space. Notes References Further reading External links |
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Contents Giant-impact hypothesis The giant-impact hypothesis, sometimes called the Theia Impact, is an astrogeology hypothesis for the formation of the Moon first proposed in 1946 by Canadian geologist Reginald Daly. The hypothesis suggests that the Proto-Earth collided with a Mars-sized co-orbital protoplanet likely from the L4 or L5 Lagrange points of the Earth's orbit approximately 4.5 billion years ago in the early Hadean eon (about 20 to 100 million years after the Solar System formed), and some of the ejected debris from the impact event later re-accreted to form the Moon. The impactor planet is sometimes called Theia, named after the mythical Greek Titan who was the mother of Selene, the goddess of the Moon. Analysis of lunar rocks published in a 2016 report suggests that the impact might have been a direct hit, causing a fragmentation and thorough mixing of both parent bodies. The giant-impact hypothesis is currently the favored hypothesis for lunar formation among astronomers. Evidence that supports this hypothesis includes: However, several questions remain concerning the best current models of the giant-impact hypothesis. The energy of such a giant impact is predicted to have heated Earth to produce a global magma ocean, and evidence of the resultant planetary differentiation of the heavier material sinking into Earth's mantle has been documented. However, there is no self-consistent model that starts with the giant-impact event and follows the evolution of the debris into a single moon. History In 1898, George Darwin made the suggestion that Earth and the Moon were once a single body. Darwin's hypothesis was that a molten Moon had been spun from Earth because of centrifugal forces, and this became the dominant academic explanation. Using Newtonian mechanics, he calculated that the Moon had orbited much more closely in the past and was drifting away from Earth. This drifting was later confirmed by American and Soviet experiments, using laser ranging targets placed on the Moon. Nonetheless, Darwin's calculations could not resolve the mechanics required to trace the Moon back to the surface of Earth. In 1946, Reginald Aldworth Daly of Harvard University challenged Darwin's explanation, adjusting it to postulate that the creation of the Moon was caused by an impact rather than centrifugal forces. Little attention was paid to Professor Daly's challenge until a conference on satellites in 1974, during which the idea was reintroduced and later published and discussed in Icarus in 1975 by William K. Hartmann and Donald R. Davis. Their models suggested that, at the end of the planet formation period, several satellite-sized bodies had formed that could collide with the planets or be captured. They proposed that one of these objects might have collided with Earth, ejecting refractory, volatile-poor dust that could coalesce to form the Moon. This collision could potentially explain the unique geological and geochemical properties of the Moon. A similar approach was taken by Canadian astronomer Alastair G. W. Cameron and American astronomer William R. Ward, who suggested that the Moon was formed by the tangential impact upon Earth of a body the size of Mars. It is hypothesized that most of the outer silicates of the colliding body would be vaporized, whereas a metallic core would not. Hence, most of the collisional material sent into orbit would consist of silicates, leaving the coalescing Moon deficient in iron. The more volatile materials that were emitted during the collision probably would escape the Solar System, whereas silicates would tend to coalesce. Eighteen months prior to an October 1984 conference on lunar origins, Bill Hartmann, Roger Phillips, and Jeff Taylor challenged fellow lunar scientists: "You have eighteen months. Go back to your Apollo data, go back to your computer, and do whatever you have to, but make up your mind. Don't come to our conference unless you have something to say about the Moon's birth." At the 1984 conference at Kona, Hawaii, the giant-impact hypothesis emerged as the most favored hypothesis. Before the conference, there were partisans of the three "traditional" theories, plus a few people who were starting to take the giant impact seriously, and there was a huge apathetic middle who didn't think the debate would ever be resolved. Afterward, there were essentially only two groups: the giant impact camp and the agnostics. Theia The name of the hypothesised protoplanet is derived from the mythical Greek titan Theia /ˈθiːə/, who gave birth to the Moon goddess Selene. This designation was proposed initially by the English geochemist Alex N. Halliday in 2000 and has become accepted in the scientific community. According to modern theories of planet formation, Theia was part of a population of Mars-sized bodies that existed in the Solar System 4.5 billion years ago. Theia is hypothesized to have orbited in the L4 or L5 configuration presented by the Earth–Sun system, where it would tend to remain. One of the attractive features of the giant-impact hypothesis is that the formation of the Moon and Earth align; during the course of its formation, Earth is thought to have experienced dozens of collisions with planet-sized bodies. The Moon-forming collision would have been only one such "giant impact" but certainly the last significant impactor event. The Late Heavy Bombardment by much smaller asteroids may have occurred later – approximately 3.9 billion years ago. Basic model Astronomers think the collision between Earth and Theia happened at about 4.4 to 4.45 billion years ago (bya); about 0.1 billion years after the Solar System began to form. In astronomical terms, the impact would have been of moderate velocity. Theia is thought to have struck Earth at an oblique angle when Earth was nearly fully formed. Computer simulations of this "late-impact" scenario suggest an initial impactor velocity below 4 kilometres per second (2.5 mi/s) at "infinity" (far enough that gravitational attraction is not a factor), increasing as it approached to over 9.3 km/s (5.8 mi/s) at impact, and an impact angle of about 45°. However, oxygen isotope abundance in lunar rock suggests "vigorous mixing" of Theia and Earth, indicating a steep impact angle. Theia's iron core would have sunk into the young Earth's core, and most of Theia's mantle accreted onto Earth's mantle. However, a significant portion of the mantle material from both Theia and Earth would have been ejected into orbit around Earth (if ejected with velocities between orbital velocity and escape velocity) or into individual orbits around the Sun (if ejected at higher velocities). Modelling has hypothesised that material in orbit around Earth may have accreted to form the Moon in three consecutive phases, accreting first from the bodies initially present outside Earth's Roche limit, which acted to confine the inner disk material within the Roche limit. The inner disk slowly and viscously spread back out to Earth's Roche limit, pushing along outer bodies via resonant interactions. After several tens of years, the disk spread beyond the Roche limit, and started producing new objects that continued the growth of the Moon, until the inner disk was depleted in mass after several hundreds of years. Material in stable Kepler orbits was thus likely to hit the Earth–Moon system sometime later (because the Earth–Moon system's Kepler orbit around the Sun also remains stable). Estimates based on computer simulations of such an event suggest that some twenty percent of the original mass of Theia would have ended up as an orbiting ring of debris around Earth, and about half of this matter coalesced into the Moon. Earth would have gained significant amounts of angular momentum and mass from such a collision. Regardless of the speed and tilt of Earth's rotation before the impact, it would have experienced a day some five hours long after the impact, and Earth's equator and the Moon's orbit would have become coplanar. Not all of the ring material need have been swept up right away: the thickened crust of the Moon's far side suggests the possibility that a second moon about 1,000 km (620 mi) in diameter formed in a Lagrange point of the Moon. The smaller moon may have remained in orbit for tens of millions of years. As the two moons migrated outward from Earth, solar tidal effects would have made the Lagrange orbit unstable, resulting in a slow-velocity collision that "pancaked" the smaller moon onto what is now the far side of the Moon, adding material to its crust. Lunar magma cannot pierce through the thick crust of the far side, causing fewer lunar maria, while the near side has a thin crust displaying the large maria visible from Earth. Above a high resolution threshold for simulations, a study published in 2022 finds that giant impacts can immediately place a satellite with similar mass and iron content to the Moon into orbit far outside Earth's Roche limit. Even satellites that initially pass within the Roche limit can reliably and predictably survive, by being partially stripped and then torqued onto wider, stable orbits. Furthermore, the outer layers of these directly formed satellites are molten over cooler interiors and are composed of around 60% proto-Earth material. This could alleviate the tension between the Moon's Earth-like isotopic composition and the different signature expected for the impactor. Immediate formation opens up new options for the Moon's early orbit and evolution, including the possibility of a highly tilted orbit to explain the lunar inclination, and offers a simpler, single-stage scenario for the origin of the Moon. Composition In 2001, a team at the Carnegie Institution of Washington reported that the rocks from the Apollo program carried an isotopic signature that was identical with rocks from Earth, and were different from almost all other bodies in the Solar System. In 2014, a team in Germany reported that the Apollo samples had a slightly different isotopic signature from Earth rocks. The difference was slight, but statistically significant. One possible explanation is that Theia formed near Earth. This empirical data showing close similarity of composition can be explained only by the standard giant-impact hypothesis, as it is extremely unlikely that two bodies prior to collision had such similar composition. In 2007, researchers from the California Institute of Technology showed that the likelihood of Theia having an identical isotopic signature as Earth was very small (less than 1 percent). They proposed that in the aftermath of the giant impact, while Earth and the proto-lunar disc were molten and vaporised, the two reservoirs were connected by a common silicate vapor atmosphere and that the Earth–Moon system became homogenised by convective stirring while the system existed in the form of a continuous fluid. Such an "equilibration" between the post-impact Earth and the proto-lunar disc is the only proposed scenario that explains the isotopic similarities of the Apollo rocks with rocks from Earth's interior. For this scenario to be viable, however, the proto-lunar disc would have to endure for about 100 years. Work is ongoing[when?] to determine whether or not this is possible. According to research (2012) to explain similar compositions of the Earth and the Moon based on simulations at the University of Bern by physicist Andreas Reufer and his colleagues, Theia collided directly with Earth instead of barely swiping it. The collision speed may have been higher than originally assumed, and this higher velocity may have totally destroyed Theia. According to this modification, the composition of Theia is not so restricted, making a composition of up to 50% water ice possible. One effort, in 2018, to homogenise the products of the collision was to energise the primary body by way of a greater pre-collision rotational speed. This way, more material from the primary body would be spun off to form the Moon. Further computer modelling determined that the observed result could be obtained by having the pre-Earth body spinning very rapidly, so much so that it formed a new celestial object which was given the name 'synestia'. This is an unstable state that could have been generated by yet another collision to get the rotation spinning fast enough. Further modelling of this transient structure has shown that the primary body spinning as a doughnut-shaped object (the synestia) existed for about a century (a very short time)[citation needed] before it cooled down and gave birth to Earth and the Moon. Another model, in 2019, to explain the similarity of Earth and the Moon's compositions posits that shortly after Earth formed, it was covered by a sea of hot magma, while the impacting object was likely made of solid material. Modelling suggests that this would lead to the impact heating the magma much more than solids from the impacting object, leading to more material being ejected from the proto-Earth, so that about 80% of the Moon-forming debris originated from the proto-Earth. Many prior models had suggested 80% of the Moon coming from the impactor. Evidence Indirect evidence for the giant impact scenario comes from rocks collected during the Apollo Moon landings, which show oxygen isotope ratios nearly identical to those of Earth. The highly anorthositic composition of the lunar crust, as well as the existence of KREEP-rich samples, suggest that a large portion of the Moon once was molten; and a giant impact scenario could easily have supplied the energy needed to form such a magma ocean. Several lines of evidence show that if the Moon has an iron-rich core, it must be a small one. In particular, the mean density, moment of inertia, rotational signature, and magnetic induction response of the Moon all suggest that the radius of its core is less than about 25% the radius of the Moon, in contrast to about 50% for most of the other terrestrial bodies. Appropriate impact conditions satisfying the angular momentum constraints of the Earth–Moon system yield a Moon formed mostly from the mantles of Earth and the impactor, while the core of the impactor accretes to Earth. Earth has the highest density of all the planets in the Solar System; the absorption of the core of the impactor body explains this observation, given the proposed properties of the early Earth and Theia. Comparison of the zinc isotopic composition of lunar samples with that of Earth and Mars rocks provides further evidence for the impact hypothesis. Zinc is strongly fractionated when volatilised in planetary rocks, but not during normal igneous processes, so zinc abundance and isotopic composition can distinguish the two geological processes. Moon rocks contain more heavy isotopes of zinc, and overall less zinc, than corresponding igneous Earth or Mars rocks, which is consistent with zinc being depleted from the Moon through evaporation, as expected for the giant impact origin. Collisions between ejecta escaping Earth's gravity and asteroids would have left impact heating signatures in stony meteorites; analysis based on assuming the existence of this effect has been used to date the impact event to 4.47 billion years ago, in agreement with the date obtained by other means. Warm silica-rich dust and abundant SiO gas, products of high velocity impacts – over 10 km/s (6.2 mi/s) – between rocky bodies, have been detected by the Spitzer Space Telescope around the nearby (29 pc distant) young (~12 My old) star HD 172555 in the Beta Pictoris moving group. A belt of warm dust in a zone between 0.25AU and 2AU from the young star HD 23514 in the Pleiades cluster appears similar to the predicted results of Theia's collision with the embryonic Earth, and has been interpreted as the result of planet-sized objects colliding with each other. A similar belt of warm dust was detected around the star BD+20°307 (HIP 8920, SAO 75016). On 1 November 2023, scientists reported that, according to computer simulations, remnants of Theia could be still visible inside the Earth as two giant anomalies of the Earth's mantle. Difficulties This lunar origin hypothesis has some difficulties that have yet to be resolved. For example, the giant-impact hypothesis implies that a surface magma ocean would have formed following the impact. Yet there is no evidence that Earth ever had such a magma ocean and it is likely there exists material that has never been processed in a magma ocean. A number of compositional inconsistencies need to be addressed. If the Moon was formed by such an impact, it is possible that other inner planets also may have been subjected to comparable impacts. A moon that formed around Venus by this process would have been unlikely to escape. If such a moon-forming event had occurred there, a possible explanation of why the planet does not have such a moon might be that a second collision occurred that countered the angular momentum from the first impact. Another possibility is that the strong tidal forces from the Sun would tend to destabilise the orbits of moons around close-in planets. For this reason, if Venus's slow rotation rate began early in its history, any satellites larger than a few kilometers in diameter would likely have spiraled inwards and collided with Venus. Simulations of the chaotic period of terrestrial planet formation suggest that impacts like those hypothesised to have formed the Moon were common. For typical terrestrial planets with a mass of 0.5 to 1 Earth masses, such an impact typically results in a single moon containing 4% of the host planet's mass. The inclination of the resulting moon's orbit is random, but this tilt affects the subsequent dynamic evolution of the system. For example, some orbits may cause the moon to spiral back into the planet. Likewise, the proximity of the planet to the star will also affect the orbital evolution. The net effect is that it is more likely for impact-generated moons to survive when they orbit more distant terrestrial planets and are aligned with the planetary orbit. Possible origin of Theia In 2004, Princeton University mathematician Edward Belbruno and astrophysicist J. Richard Gott III proposed that Theia coalesced at the L4 or L5 Lagrangian point relative to Earth (in about the same orbit and about 60° ahead or behind), similar to a trojan asteroid. Two-dimensional computer models suggest that the stability of Theia's proposed trojan orbit would have been affected when its growing mass exceeded a threshold of approximately 10% of Earth's mass (the mass of Mars). In this scenario, gravitational perturbations by planetesimals caused Theia to depart from its stable Lagrangian location, and subsequent interactions with proto-Earth led to a collision between the two bodies. In 2008, evidence was presented that suggests that the collision might have occurred later than the accepted value of 4.53 Gya, at approximately 4.48 Gya. A 2014 comparison of computer simulations with elemental abundance measurements in Earth's mantle indicated that the collision occurred approximately 95 My after the formation of the Solar System. It has been suggested that other significant objects might have been created by the impact, which could have remained in orbit between Earth and the Moon, stuck in Lagrangian points. Such objects might have stayed within the Earth–Moon system for as long as 100 million years, until the gravitational tugs of other planets destabilised the system enough to free the objects. A study published in 2011 suggested that a subsequent collision between the Moon and one of these smaller bodies caused the notable differences in physical characteristics between the two hemispheres of the Moon. This collision, simulations have supported, would have been at a low enough velocity so as not to form a crater; instead, the material from the smaller body would have spread out across the Moon (in what would become its far side), adding a thick layer of highlands crust. The resulting mass irregularities would subsequently produce a gravity gradient that resulted in tidal locking of the Moon so that today, only the near side remains visible from Earth. However, mapping by the GRAIL mission has ruled out this scenario.[citation needed] In 2019, a team at the University of Münster reported that the molybdenum isotopic composition in Earth's primitive mantle originates from the outer Solar System, hinting at the source of water on Earth. One possible explanation is that Theia originated in the outer Solar System. Alternative hypotheses Other mechanisms that have been suggested at various times for the Moon's origin are that the Moon was spun off from Earth's molten surface by centrifugal force; that it was formed elsewhere and was subsequently captured by Earth's gravitational field; or that Earth and the Moon formed at the same time and place from the same accretion disk. None of these hypotheses can account for the high angular momentum of the Earth–Moon system. Another hypothesis attributes the formation of the Moon to the impact of a large asteroid with Earth much later than previously thought, creating the satellite primarily from debris from Earth. In this hypothesis, the formation of the Moon occurs 60–140 million years after the formation of the Solar System (as compared to hypothesized Theia impact at 4.527 ± 0.010 billion years). The asteroid impact in this scenario would have created a magma ocean on Earth and the proto-Moon with both bodies sharing a common plasma metal vapor atmosphere. The shared metal vapor bridge would have allowed material from Earth and the proto-Moon to exchange and equilibrate into a more common composition. Yet another hypothesis proposes that the Moon and Earth formed together, not from the collision of once-distant bodies. This model, published in 2012 by Robin M. Canup, suggests that the Moon and Earth formed from a massive collision of two planetary bodies, each larger than Mars, which then re-collided to form what is now called Earth. After the re-collision, Earth was surrounded by a disk of material which accreted to form the Moon. See also References Notes Academic articles Non-academic books External links |
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[SOURCE: https://en.wikipedia.org/wiki/Kiryat_Bialik] | [TOKENS: 1413] |
Contents Kiryat Bialik Kiryat Bialik (Hebrew: קִרְייַת בְּיַאלִיק, also Qiryat Bialik) is a city in the Haifa District in Israel. The city was established on July 18, 1934, during the Fifth Aliyah. It is one of the five Krayot suburbs to the north of Haifa. In 2023 it had a population of 46,417. The city was named after the poet Hayim Nahman Bialik. History In 1924, Ephraim and Sabina Katz, who had immigrated to Mandatory Palestine from the Kingdom of Romania, were the first Jews in modern times to settle in the Zevulun Valley along the Haifa Bay. Their farm was destroyed in the 1929 Palestine riots. The one house that survived the riots, Beit Katz, was bequeathed to Kiryat Bialik in 1959 and designated for public use. The town of Kiryat Bialik was founded in July 1934 by a group of German Jewish immigrants who had received a plot of land from the Jewish National Fund. The residents were mainly free professionals, doctors, engineers and lawyers who lived in private homes with gardens. During World War II, parts of Kiryat Bialik were bombed due to its proximity to the oil refineries in Haifa. In 1950, it was declared a local council, attaining city status in 1976. In the early 1950s, the 'Ir HaMifratz' transit camp (also called 'Cordani A') was established, where among others, about 100 families of immigrants from India were absorbed. The transit camp was annexed to Kiryat Bialik in 1960. During the Second Lebanon War, several rockets landed in the city, causing property damage and injuring a number of residents. On September 22, 2024, during a fourth wave of rocket fire from Hezbollah, Kiryat Bialik was hit by rockets, injuring three people and damaging two houses. Magen David Adom (MDA) reported that two men, both in their 70s, and a 16-year-old girl were wounded by shrapnel. One of the men was in moderate condition, while the other two individuals sustained light injuries. All three were transported to Rambam Hospital in Haifa for treatment. Local government Neighborhoods Demographics According to CBS, the ethnic makeup of Kiryat Bialik in 2008 was all Jewish, without a significant Arab population. There were 17,900 males and 19,200 females. In 2003 25.8% of the population was 19 years of age or younger, 15.8% between 20 and 29, 17.4% between 30 and 44, 21.5 from 45 to 59, 3.8% from 60 to 64, and 15.6% 65 years of age or older. The population growth rate in 2005 was -0.3%. The city is ranked medium-high on the socio-economic scale (7 out of 10). Many Jewish immigrants have settled in Kiryat Bialik from Ethiopia, the former Soviet Union and Argentina. Economy According to CBS figures for 2002, there were 17,514 salaried workers and 912 self-employed in Kiryat Bialik. The mean monthly wage for a salaried worker was 6,119 NIS; salaried males had a mean monthly wage of 7,851 NIS versus 4,491 NIS for females. The mean income for the self-employed was 5,996 NIS. 557 people received unemployment benefits and 2,701 people received a guaranteed minimum income. The town was known for the Ata textile factory, established in 1934 by Erich Moller. The Ata plant, which opened in 1934, became an icon of the Israeli textile industry. It suffered from financial problems in the 1960s and closed down in 1985. Education According to CBS, there are 9 schools and 6,291 students in the city: 6 elementary schools with 2,540 students, and 3 secondary education schools (2 junior high and 1 high school, under the same administration) with 3,751 students. 63.4% of 12th grade students were entitled to a Bagrut (matriculation) certificate in 2002. Second Lebanon War (2006) During the Second Lebanon War in 2006, the city suffered hits from 15 Katyushas and other types of rockets sent by Hezbollah. Entertainment In the city, there is a municipal library [HE] with two branches, one in the Tzur Shalom area and one in the old Bialik area. The city has two "Pisgah Center [HE]", where various classes for children and teenagers, events, and performances are held. The "Afek Country Club" in the city features swimming pools and gyms. In 2019, the Yagur swimming pool was closed after 58 years of operation. Every year in May, the city hosts the "Bialik Festival for Literature and Poetry," which includes cultural performances, meetings with authors, concerts, and children's plays. Three youth movements operate in Kiryat Bialik: Scouts, HaNoar HaOved VeHaLomed, and HaMahanot HaOlim. Kiryat Bialik operates a conservatory for music studies and voice development and also has the "Young Bialik" youth band, which performs in Israel and abroad. The city has a museum dedicated to the history of the city, located in Beit Katz, known as Museum of the History of Kiryat Bialik. Additionally, within the city is the Kiryon Shopping Mall [HE], one of the largest shopping malls in the country and the largest in the north. The city has a promenade named after Shimon Peres along the Gedora stream, stretching over several kilometers, starting from Rabin Square in the north to HaEmekim Street in the south of the city. Additionally, there are several parks throughout the city, including: Savyon Garden, which once housed the Savyon Cinema, Miriam Garden, Esther Park, HaBanim Park in the Afek neighborhood, and a park named after Ariel Sharon in the Tzur Shalom neighborhood. Notable people Twin towns – sister cities Kiryat Bialik is twinned with: Gallery References 010,00020,00030,00040,00050,000194019501960197019801990200020102020NumberKiryat Bialik: Population |
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Contents Pan-Islamism Political Militant Pan-Islamism (Arabic: الوحدة الإسلامية, romanized: al-Waḥdat al-Islāmiyya) is a political movement which advocates the unity of Muslims under one Islamic state, often a caliphate or an international organization with Islamic principles. Historically, after Ottomanism, which aimed at the unity of all Ottoman citizens, pan-Islamism was promoted in the Ottoman Empire during the last quarter of the 19th century by Sultan Abdul Hamid II for the purpose of preventing secession movements of the Muslim peoples in the empire. Pan-Islamism differentiates itself from pan-nationalistic ideologies, for example Pan-Arabism, by focusing on religion and not ethnicity and race. It sees the ummah (Muslim community) as the focus of allegiance and mobilization, including the Tawhid belief, by the guidance of the Quran and the sunnah. The major leaders of the pan-Islamist movement were the triad of Jamal al-Din al-Afghani (1839–1897), Muhammad Abduh (1849–1905) and Rashid Rida (1865–1935), who were active in anti-colonial efforts to confront European penetration of Muslim lands. They also sought to strengthen Islamic unity, which they believed to be the strongest force to mobilize Muslims against imperial domination. Following Ibn Saud's conquest of the Arabian Peninsula, pan-Islamism would be bolstered across the Islamic world. During the second half of the 20th century, pan-Islamists competed against left-wing nationalist ideologies in the Arab world, such as Nasserism and Ba'athism. At the height of the Cold War in the 1960s and 1970s, Saudi Arabia and allied countries in the Muslim world led the pan-Islamist struggle to fight the spread of communist ideology and curtail the rising Soviet influence in the world. Classical doctrines The Arabic term ummah, which is found in the Quran and Islamic tradition, has historically been used to denote the Muslims as a whole, regardless of race, ethnicity, etc. This term has been used in a political sense by classical Islamic scholars (e.g., al-Mawardi in Al-Ahkam al-Sultaniyyah, in which he discusses the contract of the imamate of the ummah, "prescribed to succeed Prophethood" in protection of the religion and of managing the affairs of the world). Al-Ghazali also discussed the ummah in a political sense in his work Fadiah al-Batinyah wa Fadail al-Mustazhariyah. Fakhr al-Din al-Razi, who also talks about the ummah in a political sense, is quoted as saying the following: The world is a garden, whose waterer is the dynasty, which is the authority. The guardian of this authority is the Shari'ah and Shari'ah is also the policy which preserves the kingdom; the kingdom is the city which the army brings into existence; the army is guaranteed by wealth; wealth is acquired by the subjects (Ummah) who are made servants via justice; justice is the axis of well being of the world. — al-Razi in his Jami al-'Ulum The ideology draws inspiration from early Islam—the era of Muhammad and the Rashidun Caliphate—particularly during the Islamic Golden Age, a period often associated with a strong, unified, and flourishing Muslim world. History Many scholars assert that the doctrines of pan-Islamism could be observed as early as during the era of Islamic Iberia, Emirate of Sicily, the Gunpowder Empires (Ottoman, Safavid and Mughal Empires) and several Muslim sultanates and kingdoms, despite the presence and employment of non-Muslim subjects by Muslim powers. During the 18th century, multiple movements for puritanical Islamic renewal would emerge. Amongst these, the revivalist movements of three leading religious reformers – Shah Wali Allah of Delhi (1702–1763), the Arabian Muhammad Ibn 'Abd al-Wahhab (1703–1792), and the Nigerian Uthman dan Fodio (1755–1816) – are widely regarded as the precursors of the modern-era Pan-Islamist thought. Despite their calls for puritanical reform, these movements were not politically concerned with the international situation of the Muslim world, and had not elaborated comprehensive pan-Islamist programmes to combat the Western threat. Since they did not call for the revival of an international Islamic entity, their ideas and impact were limited to the local regional contexts of West Africa, Arabia, and South Asia. In spite of their diversity, these 18th century Muslim reformers were united in their condemnation of declining morality and calls for the revival of scripture-based piety. Inspired by these movements, Islamic reformers at the turn of the 19th century adopted novel strategies for overcoming the crisis faced by the Muslim world by adapting to the fast-paced transformation of its era. Their proposed approaches now oscillated between an open admiration for the technology-mediated Western ideology of societal progress and a clear rejection of it on the grounds of the axiomatic superiority of an idealized Islamic culture, rooted in Scripturalist injunctions. Two major scholars of early colonial Egypt 'Abd al-Rahman al-Jabarti (d. 1825) and Rifa'a al-Tahtawi (d. 1872) represented these intellectual trends. While Rifa'a al-Tahtawi exemplified the former, 'Abd al-Rahman al-Jabarti represented the latter, Scriptural-oriented approach. In the modern era, Pan-Islamism was championed by Jamal al-Din al-Afghani who sought unity among Muslims to resist colonial occupation of Muslim lands. Afghani feared that nationalism would divide the Muslim world and believed that Muslim unity was more important than ethnic identity. Although sometimes described as "liberal", al-Afghani did not advocate constitutional government but simply envisioned "the overthrow of individual rulers who were lax or subservient to foreigners, and their replacement by strong and patriotic men." In a review of the theoretical articles of his Paris-based newspaper there was nothing "favoring political democracy or parliamentarianism," according to his biographer. While Afghani was an advocate of revolution from above, his student 'Abduh believed in revolution from below, through religious and educational reforms. Despite al-Afghani's tremendous influence on 'Abduh, the latter eventually would distance himself from Afghani's political path. He instead focused on gradual efforts in the field of education, which he viewed as more effective instruments for reform. He criticised Afghani and pan-Islamist intellectuals for their political activities. Afghani had bitter arguments with Abduh and regularly accused him of timidity and dispiritedness. Islamic jurist Muhammad Rashid Rida – a student of Abduh and Afghani – on the other hand, was an avowed anti-imperialist and an exponent of a puritanical revolution, inspired by his nostalgia for the early eras of Islam. According to Rida, the state-sponsored scholars neglected the revival of early Islamic traditions in the Muslim Ummah. He believed that the unification of the Islamic community would only be possible through the restoration of an Islamic caliphate which implements the Sharia (Islamic law). His influential Islamic journal Al-Manar promoted anti-British revolt, as well as Islamic revivalism based on the tenets of Salafiyya. Positioning himself as the successor to the pan-Islamist activism of Afghani and 'Abduh; Rida called for a pan-Islamic project based on revival of the Islamic caliphate led by Arabs and the reformation of Muslims. During the 1920s, Rida formulated the comprehensive Islamic state doctrine in his famous treatise al-Khilafa aw al-Imama al-'Uzma ("The Caliphate or the Exalted Imamate") in which he called upon Muslims to strive to build a political system based on faith; rather than nationalism. He opposed the rising embrace of Western ideas amongst Muslims, arguing that only a return to Islam would restore the rightful position of Muslims in the modern age. Pan-Islamic networks, led by Rashid Rida and his associates, played a central role in later development of Islamist movements. Rida's Salafiyya movement advocated for pan-Islamist solidarity which involved socio-political campaigning to establish Sharia (Islamic laws). Following World War I, Rida and his disciples became the biggest adversaries of secularists and nationalists; and vehemently attacked all forms of democratic ideas. Articulating his Pan-Islamist vision, Rashid Rida wrote in Al-Manar in 1902: "In sum, what I mean by Islamic unity is that the leaders (ahl al-Hal wal-'aqd) among the scholars and notables should meet and compile a book of ordinances which is based on the deeply-rooted fundamentals of the Divine Law, agrees with the needs of the time, is easy to use, and is free of disagreement (khilaf). The Supreme Imam then orders the rulers of Muslims to apply it (al-'amal bihi)" In order to judge the rising importance of the Pan-Islamist movement during these years, Lothrop Stoddard in his 1921 book The New World of Islam looked at the growth in the Pan-Islamic press, writing that "in 1900 there were in the whole Islamic world not more than 200 propagandist journals", as he puts it, but "by 1906 there were 500, while in 1914 there were well over 1000." After the Abolition of Caliphate in 1924, Pan-Islamism mobilized Muslim masses of both traditionalist and reform movements in Islam, inspired by the ideas of Rashid Rida. The Reformist movements led by Rida, would become more fundamentalist and literalist; emphasizing adherence to the idealised era of the Salaf and attempt to revive lost traditions. Rashid Rida's socio-political views symbolised the convergence of the doctrines of the reformist, Salafist and pan-Islamist movements. During the 1920s, Rida and his Salafi disciples established the Young Men's Muslim Association (YMMA); an influential Islamist youth organisation that spearheaded attacks against liberal trends and Western culture. This provided favourable conditions for the growth of various Islamist revolutionary movements. The evolution of the early Pan-Islamist movement in the post-colonial world was strongly associated with Islamism. Leading Islamists such as Sayyid Qutb, Abul Ala Maududi, and Ayatollah Khomeini all stressed their belief that a return to traditional Sharia law would make Islam united and strong again. Extremism within Islam goes back to the 7th century to the Kharijites.[better source needed] From their essentially political position, they developed extreme doctrines that set them apart from both mainstream Sunni and Shiʿa Muslims. The Kharijites were particularly noted for adopting a radical approach to Takfir, whereby they declared other Muslims to be unbelievers and therefore deemed them worthy of death. In the period of de-colonialism following World War II, Arab nationalism overshadowed Islamism which denounced nationalism as un-Islamic. In the Arab world secular pan-Arab parties – Baath and Nasserist parties – had offshoots in almost every Arab country, and took power in Egypt, Libya, Iraq and Syria. Islamists suffered severe repression; its major thinker Sayyid Qutb, was imprisoned, underwent torture and was later executed. Egyptian president Nasser considered the idea of Muslim unity as a threat to Arab nationalism. [better source needed] In the 1950s, Pakistan's government championed Muslim cooperation like many other Muslim countries, however Pakistan's efforts were complicated with its involvement in Baghdad pact and pro-western foreign diplomacy in light of the Palestine-Israel conflict, however later relations would be much better. Many Muslim countries suspected that Pakistan was aspiring to leadership of the Muslim world to in foreword help western powers in relations with other Muslim states.[better source needed] Following the defeat of Arab armies in the Six-Day War, Islamism and Pan-Islam began to reverse their relative position of popularity with nationalism and pan-Arabism. Political events in the Muslim world in the late 1960s convinced many Muslim states to shift their earlier ideas and respond favourably to Pakistan's goal of Muslim unity. Nasser abandoned his opposition to a pan-Islamic platform and such developments facilitated the first summit conference of Muslim heads of state in Rabat in 1969. This conference was eventually transformed into a permanent body called Organisation of Islamic Conference. In 1979 the Iranian Revolution ousted Shah Mohammad Reza Pahlavi from power. Ten years later in 1989; the Afghan mujahideen, with major support from the United States, would successfully force the Soviet Union from Afghanistan. Pan-Islamic Sunni Muslims such as Maududi and the Muslim Brotherhood, embraced the creation of a new caliphate, at least as a long-term project. Shia leader Ruhollah Khomeini[Note 1] also embraced a united Islamic supra-state[Note 2] but saw it led by a (Shia) religious scholar of fiqh (a faqih). These events galvanised Islamists the world over and heightened their popularity with the Muslim public. Throughout the Middle-East, and in particular Egypt, the various branches of the Muslim Brotherhood have significantly challenged the secular nationalist or monarchical Muslim governments. In Pakistan the Jamaat-e-Islami enjoyed popular support especially since the formation of the MMA, and in Algeria the FIS was expected to win the cancelled elections in 1992. Since the collapse of the Soviet Union, Hizb-ut-Tahrir has emerged as a Pan-Islamist force in Central Asia and in the last five years has developed some support from the Arab world. A recent advocate for Pan-Islamism was late Turkish prime minister and founder of Millî Görüş movement Necmettin Erbakan, who championed the Pan-Islamic Union (İslam Birliği) idea and took steps in his government toward that goal by establishing the Developing 8 Countries (or D8, as opposed to G8) in 1996 with Turkey, Egypt, Iran, Pakistan, Indonesia, Malaysia, Nigeria and Bangladesh. His vision was gradual unity of Muslim nations through economic and technologic collaboration similar to the EU with a single monetary unit (İslam Dinarı), joint aerospace and defense projects, petrochemical technology development, regional civil aviation network and a gradual agreement to democratic values. Although the organization met at presidential and cabinet levels and moderate collaboration projects continue to date, the momentum was instantly lost when the so-called Post-Modern Coup of February 28, 1997, eventually took down Erbakan's government. See also International organisations: History: References Further reading External links |
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Contents Views of Elon Musk Elon Musk is a businessman and entrepreneur known for his leadership of Tesla, SpaceX, Twitter, and xAI. He is the wealthiest individual in the world, and a former U.S. government employee. Despite rejecting the conservative label and describing himself as a political moderate, Musk's views have become increasingly right-wing over time, leading them to be characterized as far-right and libertarian authoritarian.[a] As the owner of Twitter, he has been accused of suppressing critics and allowing the spread of misinformation. Following his involvement in European politics, Musk’s public statements have received criticism from several world leaders. He frequently comments on topics ranging from science and technology to religion and philosophy. Within the context of American politics, Musk voted for Democratic candidates from 2008 before switching to Republican candidates in 2022 and supporting Donald Trump in 2024, with whom he had previously feuded. He identifies as a "free speech absolutist" and has expressed support for universal basic income, gun rights, a carbon tax, and H-1B visas. Conversely, he has criticized the wealth tax, short-selling, government subsidies, and Wikipedia. Musk has voiced concern about the perceived dangers of artificial intelligence and climate change, while also opposing public transportation systems, rejecting labor unions, and promoting pronatalism. During the COVID-19 pandemic in 2020, Musk defied lockdown orders, calling them "fascist", supported the Canada convoy protest against vaccine mandates, and made several contentious epidemiological claims. He has promoted conspiracy theories and made controversial statements that have led to accusations of racism, sexism, antisemitism, Islamophobia, transphobia, and spreading misinformation and disinformation. While describing himself as a "pro-Semite", his remarks about George Soros and Jewish communities have drawn condemnation from the Anti-Defamation League and the White House under Joe Biden. An immigrant himself, Musk has blamed immigration policy for illegal immigration, been described as anti-immigration, and has promoted misleading narratives about voter fraud in the United States. Politics and elections Musk has been described as being closely associated with techno-libertarians, ideologically a libertarian authoritarian, and has more recently been described as far-right in regards to European politics. Having criticized and feuded with Donald Trump, Musk supported Trump for the 2024 United States presidential election as the largest financial contributor to his campaign. Soon after, by appointment of Trump, Musk was given "special government employee" status as the de facto head of the Department of Government Efficiency (DOGE). Describing himself as "a free speech absolutist," Musk has regularly criticized American and European immigration policies, and his views on transgender issues, women, and race, have been controversial. Musk advocates for the U.S. to withdraw from both NATO and the United Nations. July 14, 2018 Before embracing Donald Trump in 2024 election cycle, Musk was known to have supported Barack Obama, Hillary Clinton, and even Joe Biden in 2020. In 2014, Musk described himself politically as "half Democrat, half Republican" and "somewhere in the middle, socially liberal and fiscally conservative". By 2018, he stated that he was "not a conservative" and saw himself as a "politically moderate"; he added, "Doesn't mean I'm moderate about all issues." He stated that he had "voted overwhelmingly for Democrats, historically" but in 2022 began supporting Republicans, with his views becoming more right-wing. In 2016, prompted by the emergence of artificial intelligence, Musk has voiced support for a universal basic income; he additionally backs direct democracy and has stated he thinks the government on Mars will be a direct democracy. He supported targeting an inclusive tax rate of 40%; prefers consumption taxes to income taxes; and supports the estate tax, as the "probability of progeny being equally excellent at capital allocation is not high." In an interview with The Washington Post, Musk stated he was a significant donor to Democrats and also gives heavily to Republicans. Musk further stated that political contributions are a requirement in order to have a voice in the United States federal government. In 2019, Musk tweeted in support of the Democratic presidential candidate Andrew Yang, agreeing that universal basic income was required. The following year, Musk voiced support for Kanye West's independent run for president. Musk at the time described the United States as "[inarguably] the greatest country that has ever existed on Earth", describing it as "the greatest force for good of any country that's ever been." Musk believes democracy would not exist any longer if not for the United States, saying that it prevented this disappearance on three occasions through its participation in World War I, World War II, and the Cold War, while believing the country is not perfect and has made many mistakes. September 2, 2021 In 2021, in response to Texas governor Greg Abbott saying that Musk supported Texas' "social policies", Musk said he believed government "should rarely impose its will upon the people". The following year, Musk said that he could "no longer support" the Democrats, saying that "they have become the party of division & hate" and would be voting Republican due to Biden's support for unions and his inability to "get a lot done". In June 2022, Musk voted for Mayra Flores in a special election, stating it was the first time he ever voted Republican, while also considering Ron DeSantis in the 2024 U.S. presidential election. In November, Musk clarified he would support DeSantis if he chose to run. In January 2024, Musk participated in a forum with Bill Ackman and Democratic presidential primary challenger, Representative Dean Phillips regarding his presidential bid. During the forum, after hearing about the various challenges the Democratic Party presented to Phillips's campaign, Musk denounced the process of removing candidates from ballots as being "fundamentally anti-democratic". In July 2024, Musk called Kamala Harris an "extinctionist" due to comments about young people being anxious about having kids due to climate change. February 7, 2025 Musk criticized Donald Trump prior to his first presidency in 2016 and the two feuded in 2022, as well as subsequent years. In 2024 there flourished what was described by The Independent as a "rapid and intense bromance between two of the world's most powerful men." In February 2025, Musk publicly stated he loved Trump as "a straight man", before feuding again with President Trump in June. Before the election of Donald Trump as president of the United States in November 2016, Musk criticized Trump by saying he was "not the right guy" and did not have the "character that reflects well on the United States". Following Trump's inauguration in January 2017, Musk accepted an invitation to participate in two councils advising the president, and also criticized Trump's travel ban, regarding "citizens from certain primarily Muslim countries". In June, a few months later, he resigned from both business advisory councils in protest of Trump's decision to withdraw the United States from the Paris Agreement on climate change, stating: "Climate change is real. Leaving Paris is not good for America or the world". In May 2020, amidst Musk's restarting of Tesla assembly plant production during the COVID-19 pandemic, Trump tweeted in support of Musk, which Musk publicly thanked him for. According to Walter Isaacson's biography of Musk, he reportedly did not vote in the 2020 presidential election since he believed that it was a waste of time to vote due to California being an uncontested state. July 12, 2022 When Elon Musk came to the White House asking me for help on all of his many subsidized projects, whether it's electric cars that don't drive long enough, driverless cars that crash, or rocketships to nowhere, without which subsidies he'd be worthless, and telling me how he was a big Trump fan and Republican, I could have said, 'drop to your knees and beg,' and he would have done it. In July 2022, Trump referred to Musk as a "bullshit artist" and called Musk's contract with Twitter "rotten". Musk responded by describing Trump as being too old for the presidency, instead favoring Ron DeSantis for the 2024 presidential election. Afterwards, Trump stated on Truth Social that Musk had come to the White House requesting help with subsidized projects and that had he been asked to beg, "he would have done it"; Trump also said on Truth Social that "Now Elon should focus on getting himself out of the Twitter mess because he could owe $44 billion for something that's perhaps worthless. Also, lots of competition for electric cars!". In 2022, after Trump's Twitter suspension was reversed, Musk told Isaacson about Trump that "he's disruptive. He's the world's champion of bullshit." In 2024, New York Magazine described the feud over the past few years as "on-again, off-again". @realDonaldTrump is in the Epstein files. That is the real reason they have not been made public. June 5, 2025 A feud between Musk and Trump occurred in June 2025 following Musk's exit from the second Trump administration with his criticisms of the One Big Beautiful Bill Act. Musk described the bill as a "disgusting abomination" and alleged Trump had ties to sex offender Jeffrey Epstein. In July 2024, Musk endorsed Donald Trump shortly after the attempted assassination in Pennsylvania, and it was reported that he pledged the commitment to a pro-Trump super PAC on a monthly basis, making Musk the single largest individual donor to Trump's campaign. In September 2024, following another attempted assassination of Trump, Musk received backlash after posting the now-deleted tweet: "And no one is even trying to assassinate Biden/Kamala". The following month, at a rally in Butler, Pennsylvania, Musk declared the presidential election crucial for preserving democracy, stating that Donald Trump was the only candidate capable of achieving this. Wearing a black "Make America Great Again" cap, he warned that if Trump lost, it might be the last election, marking his first appearance at a Trump event. Musk positioned Trump as a champion of free speech, and accused Democrats of threatening various rights, including the right to vote. In December 2024, The Washington Post reported that Musk had donated $277 million to Trump and allied Republicans, making him the single largest individual political donor in the 2024 election and the largest donor since at least 2010, not counting candidates who funded their own campaigns, according to data from OpenSecrets. The Post described Musk as being referred to by some Republicans as "the Soros of the right". The concept of the Department of Government Efficiency (DOGE), a department for streamlining government efficiency, emerged in a discussion between Musk and Trump, and in August 2024, Trump committed to giving Musk an advisory role, with Musk accepting the offer. Musk was described as having more of a "technology approach", according to Vivek Ramaswamy, who was originally intended co-chair the department alongside Musk. In November 2024, he suggested that the organization could help to cut the U.S. federal budget, consolidate the number of federal agencies, and eliminate the Consumer Financial Protection Bureau. The following month, he described the final stage of DOGE as "deleting itself". While his official role is not clear, he was given "special government employee" status, with the organization created by executive order in January 2025. Soon after, Musk was criticised for his treatment towards employees, prioritized secrecy within the organization, and accused others of violating privacy laws, stating "Don't mess with DOGE" on X. March 5, 2022 Musk calls himself "a free speech absolutist", identifying his definition of free speech as "that which matches the law", while advocating that corporate censorship of speech should not go significantly beyond minimum legal requirements. He has attempted to silence some critics' speech, including journalists and non-profit organisations, and engaged in censorship on behalf of Twitter. I believe in its potential to be the platform for free speech around the globe, and I believe free speech is a societal imperative for a functioning democracy. However, since making my investment I now realize the company will neither thrive nor serve this societal imperative in its current form. Twitter needs to be transformed as a private company. In April 2022, Musk made an offer to buy Twitter, believing that "free speech is a societal imperative for a functioning democracy". Since Musk's acquisition of Twitter, the platform has increased its approval of censorship requests by governments. During the 2023 Turkish presidential election, Twitter limited access to content in Turkey, including critics of incumbent president Recep Tayyip Erdoğan, political opponents, and journalists. Musk defended this move by stating that the alternative would have been to "throttle [Twitter] in its entirety", and said it was normal for Internet companies to do. Twitter has also censored tweets and blocked accounts that are critical of India's prime minister Narendra Modi and his Bharatiya Janata Party, with Musk stating that Twitter is left with no choice but to "obey local government", as a believer in upholding lawful censorship requests. Twitter has filed strategic lawsuits against public participation for some U.S. critics, and it is facing a speech-related case involving a critic in Germany. Musk has also called for several of his critics to be criminally prosecuted. April 22, 2022 According to Musk, the alt-tech platform Truth Social[b] exists because of censorship on Twitter. In May 2022, Musk called Twitter's decision to ban Trump "morally wrong", announcing he would reverse Trump's ban when after purchasing Twitter. In November 2022, Musk tweeted that he was so committed to free speech that he would not ban @ElonJet, a Twitter account that tracked the publicly available real-time flight data of Musk's private plane. Musk reversed his position the following month, banning the account and several journalists who had reported on it, accused them of doxxing, and threatening legal action. He has also refused to block Russian state media on SpaceX's Starlink satellites in response to Russia's invasion of Ukraine. In February 2025, Tesla fired a manager who had been openly critical of Musk, a move seen at odds with Musk's purported free speech views. In March 2025, Musk pressured Reddit CEO Steve Huffman to prevent subreddits from banning links to Twitter and ban subreddits critical of the Trump administration, leading to the r/WhitePeopleofTwitter subreddit being banned for 72 hours. In an interview, Musk said he would be working with the Trump administration to "go after" people "pushing the lies" about Tesla. In the aftermath of the Uvalde school shooting in 2022, Musk supported strict background checks on all gun purchases and limiting the sale of assault rifles to those living in "high risk" locations with issues such as "gang warfare" and to owners of gun ranges. Believing in a special permit and vigorous vetting, Musk has said that he firmly believes "that the right to bear arms is an important safeguard against potential tyranny of government. Historically, maintaining their power over the people is why those in power did not allow public ownership of guns". Having previously been described as a "Silicon Valley libertarian", in late 2022, The Atlantic wrote that Musk was "a right-wing activist" who was aiding the far-right, and "appears deeply committed to the right's culture war against progressivism in most forms", while Musk affirmed he was a centrist. The magazine described his activism as being "personally motivated", as opposed to ideologically motivated. A year later, the New Statesman described his libertarianism as being "infused with authoritarian tendencies". In July 2024, Bloomberg declared Musk was "going all in on right-wing politics" and embracing the conservative movement. In October, a CNN reporter described Musk as finding Trump's authoritarian leanings appealing, and a month later, The Spectator credited Musk with bringing "the techno-libertarian elite, a small but very wealthy group, into Trump's largely blue-collar, industrial and conservative base", thus increasing the support base. In early 2025, The Conversation analysed Musk's path towards far-right politics within the context of "the libertarian to alt-right pipeline"[c] and the shift of the Libertarian Party to the right. The magazine stated that "he remains a limited-government libertarian", and that his online personality is "part of a deliberate alt-right populist strategy to stoke controversy", intended to disturb the left and claim persecution when criticized. Wired opined that Musk had become "the hero of America's far-right movement", and had become paramount within far-right community discussions. Jacobin defined his politics as libertarian authoritarianism,[d] based on his political activities combining "authoritarian nationalism with a distinctive postmodern, libertarian streak". The magazine attributed his transition into a "chief amplifier of global authoritarianism", based on his past criticisms of Black Lives Matter, diversity, equity and inclusion, and "wokeness", describing Musk as "the first truly global oligarch". Al Jazeera reported that although Musk was supported by some for his salute, his public persona remains libertarian; described as passionately protesting against regulation, government waste, and "freeing the potential of the market and of individuals". Political scientist Jean-Yves Camus argued that Musk is not a Nazi, and alongside Trump, is "self-serving rather than ideological" who instead favours an autocracy, and The Guardian hypothesised that his "closeness with rightwing populist parties" may be of benefit to his businesses. The Nation warned that Musk has raised "the specter of massive corruption and authoritarianism to an immediate threat", after U.S. Senator Bernie Sanders described Trump and Musk's attempts to restructure the federal government as "the growth of oligarchy", and part of the shift towards authoritarianism. Musk has regularly criticized American and European immigration policies. An immigrant himself, he is described as being "anti-immigration" and has distributed false information regarding immigration and voter fraud, promoted misleading narratives, and engaged in misinformation. Since the inauguration of the Biden administration in 2021, Musk has expressed various disapprovals of its immigration policies, regularly criticizing illegal immigration and the crimes allegedly committed by them, and has promoted the theory that an increase in illegal immigration is the alleged goal of "importing voters". Musk clarified his opinion that votes are coming from counting unauthorized immigrants during the census, which shifts the proportion of seats in the House of Representatives toward states with large number of undocumented immigrants, with such states predominantly voting for Democrats. Analysis from Bloomberg described his posts on the topic as those that "primarily promote misleading narratives", and helps amplify Trump's policies on immigration. BBC Verify reported that Musk's engagement with misinformation on the subject was a "key theme" since endorsing Trump in July 2024, and The Washington Post likened the imported voters theory as being "adjacent rhetoric" to the "great replacement" conspiracy theory. That year, Musk reached over one thousands tweets and over 10 billion views on the topic of immigration and voter fraud, which became his most tweeted topic. In September 2023, Musk livestreamed a visit to the Texas border with Mexico during an influx in migrant arrivals. Musk called for improving the immigration system to allow more "hard-working and honest" migrants, while also stopping illegal migrants who are breaking the law. That same month, Musk retweeted a video that showed a non-governmental organization working to assist migrants in the Mediterranean with the caption about Germany NGO ships "collecting illegal immigrants to be unloaded in Italy". Musk's retweet bore the caption "Is the German public aware of this?" to which the German Foreign Ministry responded "Yes. And it's called saving lives." Musk responded to the Foreign Ministry declaring that Germany had violated sovereignty with the remark "Has invasion vibes". The main function of the H-1B visa program is not to hire "the best and the brightest", but rather to replace good-paying American jobs with low-wage indentured servants from abroad. January 2, 2025 Musk has defended the use of H-1B visas to attract highly skilled workers to the U.S, having once been on the same visa. In December 2024, during a period of online discussion on whether H-1B visas should be reformed, he said that Silicon Valley firms need foreign workers (via H-1B) because there are not enough "super motivated" and "super talented engineers" in America. This was controversial and drew criticism from opponents of immigration who believe that importing foreign workers would negatively impact American workers, and the debate was dubbed the "MAGA Civil War". U.S. Senator Bernie Sanders criticised Musk's stance, viewing it as the importation of cheap labour that benefits billionaires. After multiple United States federal judges ruled against the Trump administration's actions, Musk in February 2025 proposed "an immediate wave of judicial impeachments". Musk in March 2025 declared: "It's like any federal judge can stop any action by the President of the United States. This is insane, and this has got to stop … at the federal level and at the state level". Following the killing of Iryna Zarutska in Charlotte, North Carolina in August 2025, Musk criticized judges and district attorneys for allowing "criminals to walk free." I disagree with the idea of unions. I just don't like anything which creates a lords and peasants sort of thing. I think the unions naturally try to create negativity in a company. Musk has been critical of trade unions. In December 2023, Musk commented that he disagreed with "the idea of unions", describing a "lords and peasants" scenario. In 2018, Musk tweeted "Nothing stopping Tesla team at our car plant from voting union ... But why pay union dues & give up stock options for nothing?" while the United Auto Workers (UAW) union was campaigning at Tesla, in the Fremont Factory in California. In February 2023, following racist comments from cartoonist Scott Adams in which he described Black people as a hate group and encouraged racial segregation, Musk opined that the media was being racist against Whites and Asians. Musk has amplified false claims of white genocide in South Africa. I'll say what I want, and if the consequence of that is losing money, so be it, [...] In May 2023, Musk attacked George Soros on Twitter after the investor sold a small stake in Tesla, comparing Soros to the Jewish supervillain Magneto. In his defence, Musk stated he believes Soros wanted to "erode the very fabric of civilization". Musk's comment was criticized as being antisemitic by the Anti-Defamation League (ADL), noting that Soros had long been the target of conspiracy theories, and by a member of the Israeli Foreign Ministry. He was also defended by a minister of Israeli's Ministry of Diaspora Affairs, who deemed the post as not being antisemitic. Musk later denied being antisemitic and described himself as a "pro-Semite". In August 2023, Musk criticized the "Kill the Boer" song which was sung by Julius Malema during a rally for the far-left South African political party Economic Freedom Fighters, asserting that the song advocated the genocide of white people, which was rejected by Malema. A month later, Musk assured Benjamin Netanyahu that he was against antisemitism. Musk discussed the issues online with a panel of right-leaning Jewish leaders including former Israeli president Reuven Rivlin, attorney Alan Dershowitz, who represented Donald Trump in his first impeachment trial, as well as several Rabbis including Shmuley Boteach, where Musk denied allegations of antisemitism and cited the suspension of Kanye West as an example of enforcement on his platform. The group also criticized the ADL's criticism of Musk. If somebody is going to try to blackmail me with advertising, blackmail me with money, go fuck yourself. Go fuck yourself. Is that clear? I hope it is. In November 2023, Musk posted a response in which he expressed his agreement with an antisemitic tweet in which Jews were described as promoting "hatred against whites", writing "You have said the actual truth." Following this, Musk said it was "super messed-up" that white people are not "allowed to be proud of their race." He was condemned by the White House for his post, described as a "hideous lie". Musk later acknowledged the tweet as a mistake, saying "I handed a loaded gun to those who hate me and to those who are antisemitic and for that I am quite sorry" and described his tweet as very foolish. Musk stated that he doesn't believe that "all Jewish communities" promote dialectical hatred towards white people and that he was "deeply offended" by the ADL, while denouncing what he described as "anti-white racism or anti-Asian racism or racism". He also tweeted that his criticism of Jews applies to more groups than just the ADL. At the DealBook Summit, journalist Andrew Ross Sorkin questioned Musk about the withdrawal of advertisers from X following his recent posts, and Musk responded denouncing advertisers of blackmail and stated "Go fuck yourself". In August 2024, Musk ignited a controversy after he shared an allegedly Islamophobic meme. He subsequently feuded with First Minister of Scotland Humza Yousaf, who described him as "one of the most dangerous men on the planet" and a "race baiter" who should be held to account. Musk responded that Yousaf is a racist "scumbag" who "loathes white people". In January 2025, at a campaign event which was staged by the German far-right political party Alternative for Germany, Elon stated that "There is too much focus on past guilt, and we need to move beyond that". That same week, Musk was criticized for a controversial gesture that was interpreted by some as a Nazi salute, which he made during Trump's inauguration, his comments about past guilt were condemned by the chairman of Israel's official memorial to Holocaust victims. In January 2026, Musk reshared a tweet about "white solidarity" and on the same day, he claimed states like California are using immigrants to create a “one-party state.” In 2018, Musk shared a post by Tesla, about the company's ranking on the Corporate Equality Index; Tesla stated, "Thanks to everyone at Tesla for making LGBTQ inclusion an important part of our culture." Musk commented, in reply to another user, "Don't buy our car if that's a problem. People should be free to live their lives where their heart takes them". In 2022, Musk reaffirmed those comments, and also posted, "Tesla scores 100/100 for 7th year in a row for LGBTQ equality" on the Corporate Equality Index. Following Musk's takeover of Twitter in October 2022, the platform has seen an increase in hate speech toward the LGBTQ community, for which he has received criticism. Musk said of gay people in March 2024, "My observation is that people are born one way or another – it is not a choice. People should find mutual love and happiness where their heart leads them. I only ask of my gay friends that they have children for the continuance of civilization." In July 2024, Musk said that a California law which bans teachers from being required to report a change in a child's gender identity or sexual orientation was the "final straw" in deciding to move the headquarters of SpaceX and Twitter from California to Texas. Musk's views on transgender issues have provoked controversy, leading to being characterized as transphobic. December 16, 2020 In July 2020, Musk made headlines when he tweeted "Pronouns suck." The tweet was interpreted by The Independent as a slight to preferred gender pronouns, and was criticized by many, including LGBTQ advocacy group Human Rights Campaign and Musk's then partner Grimes. In a later tweet, Musk stated he supported "trans", but that pronouns are "an esthetic nightmare". In December 2022, Musk again mocked preferred gender pronouns in a tweet that read "My Pronouns are Prosecute/Fauci." In a 2023 interview, Grimes said she discussed transgender topics with Musk at length. She recounted that Musk's views appeared to her to stem from "hate [of] woke culture" and his "concerns about the fertility thing"; Grimes said to him that "fertility tech … could be innovated that would help trans people". Musk stated in 2024 that he personally does use people's preferred gender pronouns, from a "standpoint of good manners". In 2020, Musk's daughter, Vivian Wilson, underwent a gender transition. Wilson changed her name, and no longer wished to be associated with her father. Walter Isaacson, who wrote a 2023 authorized biography of Musk, stated that Musk was "generally sanguine" when he initially discovered Wilson was transgender, "but then Jenna[e] became a fervent Marxist and broke off all relations". However, Isaacson's book states that due to disagreements about capitalism, Musk and Wilson were already "estranged" before Musk knew she was transgender. Isaacson wrote that Musk became politically more right-leaning in 2021, "partly triggered by his daughter Jenna's transition, her embrace of radical socialist politics, and her decision to break off relations with him." (Wilson said this was inaccurate for multiple reasons, e.g. that she opposes wealth inequality but is not Marxist.) According to Isaacson's book, Musk said that "she went beyond socialism to being a full communist and thinking that anyone rich is evil. … I've made many overtures but she doesn't want to spend time with me." June 21, 2023 In April 2023, Twitter quietly removed a policy prohibiting targeted deadnaming and misgendering of transgender users. This policy was reintroduced in 2024, however, Musk said it would be sparingly enforced, to reduce visibility of posts considered to be "repeated, targeted harassment of a particular person." In June 2023, Musk deemed the word cisgender a slur, stating that it violated Twitter's conduct policy. That same month, What Is a Woman?, a controversial documentary about transgender issues that was initially flagged by Twitter as hate speech, went viral after Musk personally promoted it and pinned it to his profile. Musk has also expressed opposition to gender-affirming care for minors and has stated he will be "actively lobbying to criminalize" such care. In July 2024, Musk said his daughter's gender dysphoria was related to being "born gay and slightly autistic"; he said he gave parental consent for her transition at the age of 16, but that he was "essentially tricked" into doing so. (Wilson disputes this, saying Musk was "not by any means tricked" but rather gave informed consent; she has also come out as bisexual rather than gay.) January 11, 2024 In January 2024, Musk declared that cisgender is a "heterophobic" word. PinkNews argued that it does not refer to heterosexual people. Science and technology January 21, 2025 Musk considers artificial intelligence to be one of the most significant threats to the human race, has received considerable criticism for his comments and actions related to the COVID-19 pandemic, supports the colonization of Mars, favors individualized transport over public transport, and has opposed banning TikTok. Musk has also been highly critical of Wikipedia; describing the encyclopedia as "woke", controlled by the mainstream media and far-left activists, and has called for its defunding. Musk has frequently spoken about the potential dangers of artificial intelligence (AI), declaring it as "the most serious threat to the survival of the human race". During a 2014 interview at the MIT AeroAstro Centennial Symposium, Musk described AI as humanity's largest existential threat, stating his belief in the need for regulatory oversight. Musk invested in DeepMind, an AI firm, and Vicarious, a company working to improve machine intelligence, and was formerly co-chairman of OpenAI as a co-founder. Musk later criticized OpenAI for becoming closed-sourced and for-profit, and interpreted its chatbot ChatGPT of political bias. In March 2023, he signed an open letter calling for a pause on large-scale AI experiments, citing profound risks for society. The president of the Information Technology and Innovation Foundation (ITIF), Robert D. Atkinson, argued that Musk and others stating that AI is the "largest existential threat to humanity" is "not a very winning message if you want to get AI funding out of Congress to the National Science Foundation." I like to just keep an eye on what's going on with artificial intelligence. I think there is potentially a dangerous outcome there. There have been movies about this, you know, like Terminator, [...] In 2014, Musk expressed his concerns referencing Terminator, stating "we should try to make sure the outcomes are good, not bad". In 2015, as an advisor to the nonprofit Future of Life Institute, an organization focused on advanced technologies, Musk donated $10 million. The following year, when asked whether he thinks humans live in a computer simulation, perhaps controlled by a vast AI, Musk stated that "the odds that we're in 'base reality' is one in billions." Harvard physicist Lisa Randall disputed this arguing there was "no real evidence" of a simulation. At the 2019 World AI Conference, Musk contended that "computers are already smarter than human beings" and that this alone was reason for caution regarding AI.: 39 Musk warned of unintended consequences of AI and stated that immediate steps should be taken to prevent disaster.: 39 Musk's opinions about AI have provoked controversy and have been criticized by experts such as Yann LeCun, who contended that Musk's panic was influenced by reading Nick Bostrom's book Superintelligence, and by Musk's attraction to the idea that he will save humanity. Facebook's head of AI said that Musk was ill-informed about AI and noted that his comments about a future machine takeover distracts people from real, immediate AI concerns, such as algorithms exacerbating inequality. Consequently, according to CNBC, Musk is "not always looked upon favorably" by the AI research community. Mark Zuckerberg has clashed with Musk on the issue and called his AI warnings "pretty irresponsible". In November 2024, while speaking at the AI Safety Summit in London, attended by world leaders and tech figures, Musk applauded the Prime Minister Rishi Sunak for hosting the event. In doing so, he reiterated his concerns that the intelligence is "potentially the most pressing [existential risks] that we face", while anticipating that it would become "far more intelligent" than human beings. March 19, 2020 Musk has received criticism over his views and actions related to the COVID-19 pandemic. In early 2020, Musk referred to COVID-19 as a "specific form of the common cold", stated that "the coronavirus panic is dumb", and that the "danger of panic still far exceeds danger of corona imo [in my opinion]. If we over-allocate medical resources to corona, it will come at expense of treating other illnesses". Musk has additionally been criticized for tweeting contentious comments on the disease, including that "Kids are essentially immune, but elderly with existing conditions are vulnerable", and for speculating that the pandemic would soon be ending according to "current trends". In addition, he promoted articles which suggested that healthcare companies were inflating COVID-19 case numbers for financial reasons. When the Alameda County Sheriff ordered all non-essential businesses to shut down, Musk and Tesla initially refused to comply, arguing that vehicle manufacturing and energy infrastructure are critical sectors, citing the U.S. Department of Homeland Security. Musk called the lockdown "fascist" on a Tesla earnings call, comparing the restrictions to forced imprisonment, and later sent out numerous tweets opposing mandatory lockdowns such as "FREE AMERICA NOW." In March 2020, in response to a request to repurpose the Tesla factory to make urgently needed ventilators, Musk promised that Tesla would make ventilators "if there is a shortage". When Nate Silver responded that there was a current shortage, Musk replied, "Ventilators are not difficult, but cannot be produced instantly." After figures such as New York City mayor Bill de Blasio highlighted their hospitals' ventilator shortage and responded to Musk's offer, Musk said he thought the ventilators which Tesla was working on would probably be unneeded. A week later, Musk received widespread requests from dignitaries around the world, including the Ukrainian Health minister, Bolivia's Ambassador for Science and Technology to Silicon Valley, and Nigeria's Ministry of Finance. When asked about what they received from Musk, California hospital representatives noted that they received CPAP machines made by ResMed instead and not "full ventilators", though expressed gratitude. May 11, 2020 In May 2020, Musk reopened Tesla's Fremont production line in defiance of and in violation of Alameda County's orders, and tweeted that "If anyone is arrested, I ask that it only be me." Musk also announced that Tesla would be moving its headquarters to Texas or Nevada and that Tesla had filed a lawsuit against Alameda County challenging its "shutdown" of the Fremont factory; the suit was subsequently withdrawn. The Alameda County Public Health Department explained it was waiting on a plan that Tesla had promised to provide by May 11 that would walk through how it would protect workers' health during the COVID-19 pandemic. An opening date of Monday, May 18 had been penciled in for Tesla, pending approval — the same date that Fiat Chrysler, Ford Motor Company, and General Motors were also due to restart production. November 14, 2020 In November 2020, the phrase "Space Karen" began to trend on Twitter after a scientist referred to Musk as such, over comments Musk made questioning the effectiveness of COVID-19 testing. Musk was also said to have spread misinformation about the virus by virologist Angela Rasmussen. with Musk referring to the virus as "a type of cold". The following month, Politico named Musk's prediction that there would be "close to zero new cases" as one of "the most audacious, confident and spectacularly incorrect prognostications about the year". Two years later, Musk tweeted "My pronouns are Prosecute/Fauci", drawing attention from US lawmakers. In February 2023, he praised anti-vaccine comments made by Woody Harrelson during Saturday Night Live. In February 2025, Musk claimed during an interview with Fox News' Sean Hannity that International Space Station (ISS) crew Suni Williams and Butch Wilmore "were left up there for political reasons, which is not good." This claim was challenged by former ISS commander Andreas Mogensen which caused Musk to attack Mogensen calling him an "idiot" and "fully retarded". Mogensen responded to the attack saying "Elon, I have long admired you and what you have accomplished, especially at SpaceX and Tesla. You know as well as I do, that Butch and Suni are returning with Crew-9, as has been the plan since last September. Even now, you are not sending up a rescue ship to bring them home. They are returning on the Dragon capsule that has been on ISS since last September." Mogensen received the support of fellow astronauts brothers Mark Kelly and Scott Kelly, Musk responded saying that Mogensen had attacked him "despite having no idea what ACTUALLY happened." and by posting on X at Scott Kelly "Btw, your brother claims to be independent, but is just a Dem donor shill." Musk's innaccurate claim that Williams and Wilmore had been abandoned by the Biden administration was repeated by President Trump. Following the digital dispute, Musk argued that the ISS should be deorbited early and that the funds should be redirected to Mars exploration. Musk clarified that his view was that "The decision is up to the President, but my recommendation is as soon as possible. I recommend 2 years from now," July 27, 2021 Musk has long been an advocate for space colonization, especially the colonization of Mars. As early as 2001, Elon became involved with the nonprofit Mars Society and has repeatedly pushed for humanity colonizing Mars, in order to become an interplanetary species and lower the risks of human extinction. In 2002 he left the society and began focusing on his own initiatives, and later envisioned establishing a direct democracy on Mars, with a system in which more votes would be required to create laws than remove them. Concerned with human population decline, Musk has described becoming "a multiplanet civilization". Musk has also cited the expansion of the sun as a reason for colonizing mars. Musk has been highly critical of the F-35 program. He has also been critical of crewed aircraft in general declaring that "The fighter jet era has passed." at the Air & Space Forces Association's 2020 Air Warfare Symposium and writing "manned fighter jets are obsolete in the age of drones anyway. Will just get pilots killed." in 2024. At a Tesla event on the sidelines of the Conference on Neural Information Processing Systems in December 2017, Musk expressed his disappointment with public transport, citing the timing and locations for reasons why "everyone doesn't like it", suggesting this was why people prefer "individualized transport" instead. Afterwards, he dismissed an audience member's response that public transportation functioned effectively in Japan. His comments sparked widespread criticism from both members of the public and transit experts. Urban planning expert Brent Toderian started the hashtag #GreatThingsThatHappenedonTransit, which was widely adopted by Twitter users to dispel Musk's notion that everyone hated public transport. Yonah Freemark, an urbanist and journalist specializing in planning and transportation, summarized Musk's views on public transport as being terrible. Jarrett Walker, a public transport expert, said that "Musk's hatred of sharing space with strangers is a luxury (or pathology) that only the rich can afford", referring to the theory that planning a city around the preferences of a minority yields an outcome that usually does not work for the majority. Musk responded with "You're an idiot", then specified "sanctimonious idiot". The exchange received a significant amount of media attention and prompted Nobel laureate Paul Krugman to criticise the controversy. In April 2023, Musk said he opposed banning TikTok in the United States, arguing that a ban would increase Twitter's active user base. In 2024, Musk opposed Australian plans to fine social media sites which enabled misinformation on their platforms, and to limit social media access for those under 16, with Musk commenting that it "Seems like a backdoor way to control access to the Internet by all Australians." In 2019, Musk described his Wikipedia article as "insane" and described it as a "war zone". In 2020, he encouraged his Twitter followers to "trash" the page, which led to the article being protected. In 2021, he wrote that he was glad Wikipedia existed. In April 2022, Musk tweeted: "They say history is written by the victors, but not on Wikipedia if the losing party is still alive & has lots of time on their hands!", in a reference to the article of Tesla Inc. co-founder Martin Eberhard. December 17, 2022 Musk responded to the December 2022 Twitter suspensions Wikipedia entry by proclaiming the site was "controlled by the MSM [mainstream media]", and that this makes it untrustworthy. In response, the Wikimedia Foundation changed a message appealing for donations to "Wikipedia is not for sale", stating "there is no danger that someone will buy Wikipedia and turn it into their personal playground". October 26, 2024 In October 2023, Musk criticized Wikipedia as "inherently hierarchical" and being "subject to the biases of higher ranking editors." In response to the Wikipedia funding appeal, Musk offered $1 billion in funding if Wikipedia changed its name to "Dickipedia". In October 2024, Musk stated the website was "controlled by far-left activists", discouraged donations, and characterized the online encyclopedia using the phrase "woke mind virus". In January 2025, Musk called for Wikipedia to be "defunded" and referred to it as "legacy media propaganda", in response to his Wikipedia article being edited to describe the alleged "Nazi salute" he gave during a speech after the second inauguration of Donald Trump. Wikipedia co-founder Jimmy Wales responded by saying: "If Elon wanted to help, he'd be encouraging kind and thoughtful intellectual people he agrees with to engage." Le Monde and the Agence France-Presse described Wikipedia as being a "natural adversary to X": In March 2025, Margaret Talbot wrote an article in The New Yorker dealing with the topic: "Elon Musk Also Has a Problem with Wikipedia". Talbot connected Musk's documented promotion of misinformation and his attacks against "mainstream media" with his admiration for "radical-right populism", citing how a study connected such conservative views with the "propensity to spread misinformation": International relations Musk's comments and actions have received condemnation from some of the governments and leaders for his involvement in European politics, including UK Prime Minister Keir Starmer, President of France Emmanuel Macron, Chancellor of Germany Olaf Scholz, and Prime Minister of Norway Jonas Gahr Store. He has been critical of Israel's actions in the Gaza Strip during the Gaza war, praised China's economic and climate goals, suggested that Taiwan and China should resolve Cross-strait relations in China's favor, and was described as having a close relationship with the Chinese government. In Europe, Musk expressed support for Ukraine in 2022 during the Russian invasion, but later backtracked, recommending Ukraine cede its Russia-occupied territories, often mocking Zelensky, and supported the far-right Alternative for Germany in Germany in 2024. Regarding British politics, Musk blamed the 2024 UK riots on mass migration and open borders, criticized Starmer for what he described as a "two-tier" policing system, suggested British politician Jess Phillips should be imprisoned, and that Starmer was complicit in child sexual exploitation. Musk was subsequently invoked as being responsible for spreading misinformation and amplifying the far-right. He has also voiced his support for far-right activist Tommy Robinson and pledged electoral support for Reform UK. In February 2026, Musk described Spanish Prime Minister Pedro Sánchez as a "tyrant" following Sánchez's proposal to prohibit users under the age of 16 from accessing social media. Conspiracy theories May 9, 2023 In November 2022, Musk shared a right-wing fake news website which promoted a conspiracy theory about the attack on Paul Pelosi. The following year, in the wake of a mass shooting at an outlet mall in Allen, Texas, Musk baselessly tried to cast doubt on evidence collected by journalists regarding the shooter's political beliefs, describing the event as a "psyop". Musk doubled down on his denial of the evidence that the shooter was a white supremacist in a CNBC interview 10 days later. Musk also boosted a tweet promoting an antisemitic blood libel conspiracy theory about adrenochrome, frequently invoked as part of QAnon. In November 2023, Musk endorsed a tweet referencing an antisemitic conspiracy theory that "hordes of minorities" are infiltrating Western countries and that Jews are pushing hatred against white people. The White House condemned Musk's endorsement of the tweet as "unacceptable". He also shared a meme promoting the widely discredited far-right Pizzagate conspiracy theory, and after a few hours, Musk deleted the tweet. In 2025, Musk promoted the Russia investigation origins conspiracy theory about Russian interference in the 2016 elections. Finance and taxes Musk has spoken against a proposed wealth tax and said that in general he supported estate taxes. He is also opposed to Grantor Retained Annuity Trusts. In 2024 Musk called a proposal from the British government to increase estate taxes on farms valued at more than a million pounds "going full Stalin." Musk is an opponent of short-selling, has repeatedly criticized the practice, and argued it should be illegal. He has engaged with short-selling critics via social media and used Tesla merchandise as a means of mocking those who short the Tesla stock. On the topic of subsidizing renewable energy, Musk has stated that he does not believe the U.S. government should provide subsidies to companies but should instead use a carbon tax to price in the negative externality of climate change and discourage poor behavior. Musk believes that the free market would achieve the best solution, and that producing environmentally unfriendly vehicles should come with its own consequences. Musk has advocated against funding for charging stations in the Infrastructure Investment and Jobs Act, maintaining that oil and gas subsidies should also be eliminated. Vermont Senator Bernie Sanders refuted Musk, describing his hypocrisy for receiving "billions in corporate welfare" before opposing a $2 trillion stimulus package that included provisions for specific companies and interest groups. Musk has subsequently doubled down on his stance and called for ending the US $7,500 tax credit for buyers of electric cars. Philosophy and religion August 26, 2022 Musk holds strong pronatalist views; The Guardian has characterized Musk as "The world's most famous pronatalist", and according to The Wall Street Journal, he has had at least 14 children with four women. Musk believes that vaginal delivery result in reduced skull size and as a result supports routine cesarean sections over natural births. Speaking at The Wall Street Journal's CEO Council session in 2021, Musk stated that a declining birth rate, and consequent population decline, is one of the biggest risks to human civilization. The following year, he argued that population collapse, due to low birth rates, is a superior risk to civilization than global warming, and his views on population collapse were challenged by demographers. In 2023, Musk has asserted that declining birth rates pose an existential threat to humanity and has donated ten million dollars to the University of Texas at Austin to further research on the potential risks. Musk has also argued that "smart" people in particular are not having children, a view which has been criticized as too close to eugenics. Speaking about natalism in 2024 Musk said "You've got to walk the talk, so I do have a lot of kids and I encourage others to have lots of kids." July 27, 2024 Musk was raised in the Anglican Church, in which he was baptized. In 2013, when he was asked if he thought that science and religion could co-exist, Musk replied "Probably not", and in 2017 he denounced a plan to create a religion which is based on the worship of an artificially intelligent 'Godhead'. By 2023, Musk had said that he considers himself "aspirationally Jewish", and noted the influence that his attending a Hebrew preschool had on him. The following year, Musk tweeted about Christianity, stating he is a believer in the principles of Christianity, such as love thy neighbor as thyself and turn the other cheek. He also engaged in a viral two-hour conversation with Jordan Peterson that explored various topics, including the role of Christianity in his life. During the interview, he described himself as a "cultural Christian". In 2024, Musk stated that he is a "big believer in the principles of Christianity". Notes References Further reading |
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[SOURCE: https://en.wikipedia.org/wiki/Lobbying] | [TOKENS: 10410] |
Contents Lobbying Government relations (also known as government affairs or legislative affairs), is a form of advocacy that legally attempts to influence and/or understand policy decisions made by legislators, members of regulatory agencies in the executive branch, or in some cases judges. Lobbying, a major and most well known component of government relations on the other hand, consists of "directly advocating for or against particular legislation or regulations." The work of advocates and lobbyists generally include activities that require direct contact with lawmakers, policymakers, and/or their staff; most often professional lobbyists require entry in a lobby register as a registered lobbyist, while most other advocates do not. Although the profession of government relations, as well as the public affairs industry, are not exclusive to lobbyists, it also includes advocates and non-lobbyist government relations professionals that assist lobbyists or other influence efforts but are not legally classified as such. A principal is a person or organization that hires a lobbyist, or is a senior member of an organization or advocacy group that is advocating on behalf of itself and/or coordinates constituent meetings with lawmakers on behalf of interested individuals from the general public. Overview Lobbying involves direct meetings with legislators to influence policy decisions based on their political interests and goals. Lobbying can be carried out by various entities, including individuals acting as constituents, corporations pursuing business interests, nonprofits, NGOs through advocacy groups, interest groups, and political action committees. Some government relations practices may include the use of campaign finance by contributing endorsements for political candidates and proposed public policies to achieve a group's political interests. While there are different types of lobbying, the main form of lobbying to influence government action is by meeting with legislators. Groups that hire lobbyists will endorse expenditures, which refers to the total dollars spent on lobbying activity. These expenditures usually go towards setting up direct meetings with lawmakers, extensive data and research on policies, drafting proposals, and testimonies. During these meetings, lobbyists will share case studies, research, and relevant data in order to frame their policy strategy and solution as highly credible to legislators. Credibility is a huge factor in lobbyist-legislator relationships as it builds a sense of trust and cooperation in the policy making process aiming to advance or block certain policies. When government relations work is done in-house among non-profit organizations, humanitarian aid organizations, trade unions, professional associations, trade associations, or chambers of commerce, it is referred to as policy and advocacy; where lobbying alongside litigation, public education, coalition building, capacity building, and other types of advocacy, is known as one of several components to the activity known as policy advocacy. It is also an industry known by many of the aforementioned names, and has a near-complete overlap with the public affairs industry. Legislative relations can include legislators influencing each other or government officials in the executive and judicial branch agencies reporting to and/or interacting with the legislative branch through their respective offices of legislative affairs. In government relations, and advocacy in general, practitioners may fall into several different categories. A "principal", is a person, organization, or member of an organization that hires a lobbyist to represent their interests before lawmakers or their staff in direct lobbying settings, or a (paid grassroots staff member or unpaid volunteer) "senior member" of an organization or advocacy group that is advocating for a certain cause on their own behalf without a registered lobbyist and coordinates constituent meetings between advocates, the legislators that represent them individually, and on on behalf of interested individuals from the general public when conducted in grassroots lobbying settings. "Advocates" (also known as "amateur lobbyists" or "volunteer lobbyists") who are practitioners of grassroots lobbying, such as individual voters/voter blocs within an electoral district, community organizers, (paid or unpaid) grassroots staff members, or amateur non-professional volunteers at advocacy groups and political organizations, who are there either as "constituent advocates" (i.e. constituents) ready to share their views and concerns with the lawmaker(s) that represent(s) them, or as principals and "non-constituent advocates" ("NC") reaching out to legislators' offices for which they are not a constituent of with the goal of advocating for specific causes the coordinating organization supports. In a legal sense advocates and amateur lobbyists may not even be classified as lobbyists at all due to not meeting the threshold for registration. "Professional lobbyists" (most often simply referred to as "lobbyists" with no qualifier) are practitioners of direct lobbying, they engage in lobbying as a business or profession by trying to influence legislation, regulations, government decisions, actions, or policies on behalf of a group or individual who hires them and are generally required to enter their names into a lobby register as "registered lobbyists". Then there are "non-lobbyist government relations and public affairs professionals" (such as consultants, administrative/program/project/secretarial/legislative support staff, researchers, lawyers, government relations specialists, legislative assistants, legislative coordinators, and, public relations/communications professionals, among others) who work on behalf of professional lobbyists but may not actively engage in directly influencing or face-to-face meetings with targeted individuals to the extent required for registration as lobbyists, operating within the same professional circles as registered lobbyists (i.e. not all government relations professionals are lobbyists, while all lobbyists are generally considered government relations professionals). Nonprofit organizations, advocacy groups, volunteer coalitions, and political action committees may also engage in lobbying as part of their mission-related activities. Governments often define "lobbying" for legal purposes, and regulate organized group lobbying that has become influential. Requiring disclosure of financial expenditures, the identities of clients, and the specific issues being lobbied in order to promote transparency and limit potential conflicts of interest. The international standards for the regulation of lobbying were introduced at four international organizations and supranational associations: 1) the European Union; 2) the Council of Europe; 3) the Organization for Economic Cooperation and Development; 4) the Commonwealth of Independent States. Governments can define and regulate organized group lobbying as part of federal laws to prevent political corruption, thereby establishing transparency about possible influences by public lobby registers. The Lobbying Disclosure Act (LDA), established in 1995, is a comprehensive reporting and disclosure framework that all registered lobbyists in the United States must follow. This act requires all lobbying firms to report expenditures that meet lobbying activity criteria. These disclosure statements must be filed every quarter corresponding to the two year legislation period and are accessible by the public. Laws that regulate lobbying are extremely important for political and public transparency. Requiring registered lobbyists to file their activities allows for these contributions to be tracked, transparency of which groups are spending the most on lobbying, and which policies are receiving the most expenditures. Although these reports do not specify the policies certain groups are lobbying on, citizens are able to find out which groups are actively participating in lobbying and who spends the most in each sector. Having laws regulating lobbying holds lobbyists accountable by making their actions visible and prevents political corruption through public oversight. As there are laws regulating lobbying, there are often loopholes in these frameworks. The Lobbying Disclosure Act (LDA) has several loopholes and weaknesses that allow lobbying influences to occur with limited transparency. A significant implication of the LDA is the narrow definition of what is considered lobbying activity. To fall under this criteria, an individual must spend 20% or more of their time lobbying for a client and have more than one lobbying contact in a six month period. This means that firms that do not meet the 20% criteria are not required to disclose their lobbying activity. The time spent lobbying include time spent on policy research, strategizing for policy outcome, testimony, and drafting language. As a result of this, many firms deliberately structure jobs for employees to stay at 19% or less lobbying time on paper to directly avoid reporting their activities. In doing so, many firms also split lobbying work across multiple employees to avoid one single client reaching the 20% threshold. Reform advocates of the LDA argue that this criteria focuses on the technical behavior of lobbying activities rather than policy influence. Many propose eliminating the 20% threshold and instead require that all registered lobbying activity is reported. The LDA has been somewhat effective in encouraging lobbying transparency, however it is weakly enforced. The LDA authorizes the Department of Justice to enforce compliance, violations of the act can result in civil penalties and fines, even criminal penalties resulting in jail time. These penalties are often weakly enforced because the LDA depends on self-reporting files from lobbying firms which can be unreliable. The revolving door concept disproportionately affects the lobbying industry. This is the cycle of former congress members switching between the roles as legislators and regulators, and with the roles of the industries affected by legislation and regulation. This is a major implication because one of the main assets for successful lobbying is the ability to directly contact and influence government officials. "Revolving door" lobbyists are able to use their inside knowledge on current legislation and use established personal relationships from their previous government jobs to sway policy outcomes. This climate is attractive for ex-government officials as it can bring substantial monetary rewards for lobbying firms, government projects, and contracts worth millions of dollars for those they represent. When there are large corporations and groups competing to sway policy outcomes to reach their objectives, there is the implication of public interests being overshadowed. Lobbying can overshadow public interests when well-funded groups have more access to legislators, influence, and resources than ordinary citizens. Industries with high financial budgets are able to hire teams of lobbyists, fund political campaigns through PACs, and ultimately support candidates likely to align and protect their private political interests. This creates a system in which lawmakers might prioritize donor concerns over voters. On the contrary, the general public often have limited influence through voting, petitions, and lack direct access to lawmakers. Industries with high levels of lobbying activity mean that the specific industry spends a lot of money, time, and effort attempting to influence laws and regulations that affect that industry. Many industries with heavy political influence, such as the pharmaceutical, oil/gas, technology, and finance industries will actively try to shape laws passed by Congress, regulations written by agencies, tax policies, and government contracts by hiring lobbyists to shape their market. About 70% of all lobbying activity are from business groups. According to OpenSecrets in 2025, the US Chamber of Commerce spent about $53.7 million in lobbying activities as the number one top spender. Second, the National Association of Realtors spent about $38.4 million and third Pharmaceuticals of America spending at about $29.7 million. This reflects that industries and corporations that spend the most on lobbying have more at stake if certain policies are passed or not. The goal is to strategize policy outcomes to favor their respected industry. Lobby groups generally concentrate their efforts on legislatures, the process in which laws and policies are passed, as well as at the executive branch, where laws are enforced by regulatory agencies; but may also use the judiciary to advance their causes. For example by acting as parties or amici curiae (intervenors) in lawsuits. For example, the National Association for the Advancement of Colored People (NAACP), filed suits in state and federal courts in the 1950s in aims to challenge segregation laws. Their efforts resulted in the Supreme Court declaring such laws as unconstitutional. Lobbyists and non-lobbyists may use a legal device known as amicus curiae (lit. 'friend of the court') briefs to try to influence court cases. Briefs are written documents filed with a court, typically by parties to a lawsuit. Amici curiae briefs are briefs filed by people or groups who are not parties to a suit. These briefs are entered into the court records and give additional background on the matter being decided upon. Advocacy groups use these briefs both to share their expertise and to promote their positions. In 2013, the director general of the World Health Organization, Margaret Chan, illustrated the methods used in lobbying against public health issues: Efforts to prevent noncommunicable diseases go against the business interests of powerful economic operators. In my view, this is one of the biggest challenges facing health promotion. [...] it is not just Big Tobacco anymore. Public health must also contend with Big Food, Big Soda, and Big Alcohol. All of these industries fear regulation, and protect themselves by using the same tactics. Research has documented these tactics well. They include front groups, lobbies, promises of self-regulation, lawsuits, and industry-funded research that confuses the evidence and keeps the public in doubt. Tactics also include gifts, grants, and contributions to worthy causes that cast these industries as respectable corporate citizens in the eyes of politicians and the public. They include arguments that place the responsibility for harm to health on individuals, and portray government actions as interference in personal liberties and free choice. This is formidable opposition. [...] When industry is involved in policy-making, rest assured that the most effective control measures will be downplayed or left out entirely. This, too, is well-documented, and dangerous. In the view of WHO, the formulation of health policies must be protected from distortion by commercial or vested interests. Lobbying can be categorized as inside lobbying, which directly interacts with decision-makers, or outside lobbying, which pressures decision-makers through mobilization of public opinion. According to a 2025 review of research on lobbying, three effects of lobbying have been documented in the academic literature: First, in line with public suspicions, lobbyists have transactional relationships with public officials in which they exchange money for political access and influence. Second, lobbyists persuade public officials by providing information that changes the positions taken by policymakers. Third, successful mobilization of citizen support or lobbying coalitions helps lobbyists attain policy aims. Public affairs generally refers to the engagement efforts between organizations, often times in the context of building business or governmental relationships. The industry has developed over recent years and is normally considered a branch or sub-discipline of public relations (PR). Having such a broad range of coverage regarding its definition, public affairs is, by nature, a hybrid of disciplines that relies heavily on strategic communication. While often equated with lobbying, this is usually only a small part of what a public affairs practitioner might do. Other typical functions include research, strategy planning and providing advice. Dr. Juan-Carlos Molleda writes, “Many types of organizations virtually and physically interact and communicate with publics and/or audiences outside of their own country of origin to build a dynamic set of relationships. Trade, direct foreign investment, political coalitions, worthy global causes, information flow, and social networking, among other phenomena, are increasing the complexity of those relationships dramatically”. Organizations who make use of public affairs are typically large companies, charities, trade unions, membership organizations and interest groups. They will either have staff working directly for them or employ a firm of public affairs consultants. Very often public affairs staff will work with their non-PR colleagues who are experts in a given field. Public affairs fundamentally has a global impact, and it is necessary to view it through the lens of the perspective nation in which it is being practiced. Given public affairs’ current development, there is still a common perception among those not within the industry that synonymize public affairs with lobbying, as well as public relations. Within the Global North, public affairs entails not only the former, but additionally information monitoring, media management, event planning and organization, political marketing, and of course, networking. The industry itself is expected to grow in employment opportunities by 7% between 2019 and 2029 in the US, faster than the average for all other occupations, and can mostly be contributed to the growing need for organizations to maintain their public image in such a media-abundant society. It is difficult to determine the size of the public affairs industry in the United Kingdom. Studies suggest the industry is becoming more professionalized, and that it is more widespread than often assumed. The Chartered Institute of Public Relations (CIPR), which is the UK's professional body for public relations including public affairs, estimates there are around 48,000 people involved in PR, of which 30% are involved in public affairs. This research is limited as it only measures specific job titles and those who declare themselves to be working in PR. There are large numbers of professionals providing public affairs services while working under different job titles across a wide variety of sectors. The job titles of public affairs practitioners may vary, depending on the focus of their role, but may include, "public affairs", "external affairs/relations", "corporate communications", "government/parliamentary affairs" and "policy". Worldwide, the industry is expected to grow from $63.8 billion in 2018 to $93.07 billion by 2022. North America is currently holding the largest segment of that value, and is expected to maintain its standing, followed by Europe, with an increased investment in digital programmatic public relations efforts overall. Globally, governments are continuing to enforce data protection laws in order to protect individuals against unfair government or business practices, through regulations such as the General Data Protection Regulation (GDPR) in the European Union. In the United States, President Barack Obama has introduced several measures intended to increase transparency in public affairs. In an attempt to close the "revolving door" of executive-branch officials becoming lobbyists immediately following the expiration of their federal appointments, he issued Executive Order 13490 on January 21, 2009, dictating, among other things, a two-year ban on lobbying for former top executive branch officials related to any issue that they worked on during their final year in government employment. He also introduced a ban on verbal communication between lobbyists and the federal agencies tasked with awarding economic recovery funds. These measures have proved controversial and while some argue they are a positive and necessary step, others have deemed the policies as failures due to various loopholes. The importance of media and the distribution of information in public affairs industry has experienced a myriad of trends over the last few decades. Between the 1950s and 1970s, studies found that there was an increase in the consumption of news through television broadcasting, while the newspaper decreased in circulation during this period. A study done in 1970 by Peter Clarke and Lee Ruggles also found that during this evolution from print to radio and television news, people still would turn to print or newspapers for local news, more often than national or international news on public affairs as it was considered easier to follow and understand. Moving into the 1980s and 1990s, the increased exposure to the readily available coverage of politics and public affairs, it was found that those who were interested in such information, readily sought it out and enjoyed discussing it with others. This sense of community and interest in conversing about such topics continues to evolve and has resulted into what is known today as social media. In fact, in the last decade or so, particularly among younger people, the consumption of news in general has declined and there is a reliance on getting information through social media. Thus, social media outlets such as Facebook and Twitter being some of the most popular, in addition to news apps, are increasingly becoming the main sources of political and public affairs news, and news in general. History and etymology In pre-modern political systems, royal courts provided incidental opportunities for gaining the ear of monarchs and their councilors. That architectural sense of lobby is believed to originate from the medieval Latin lobia or lobium, which refers to a gallery, hall, or portico. This architectural sense was later adopted to describe the practice of advocating or debating in such spaces. In a report carried by the BBC, an OED lexicographer has shown that "lobbying" finds its roots in the gathering of Members of Parliament and peers in the hallways ("lobbies") of the United Kingdom Houses of Parliament before and after parliamentary debates where members of the public can meet their representatives. One story held that the term originated at the Willard Hotel in Washington, D.C., where it was supposedly used by President Ulysses S. Grant to describe the political advocates who frequented the hotel's lobby to access Grant—who was often there in the evenings to enjoy a cigar and brandy—and then tried to buy the president drinks in an attempt to influence his political decisions. Although the term may have gained more widespread currency in Washington, D.C., by virtue of this practice during the Grant Administration, the OED cites numerous documented uses of the word well before Grant's presidency, including use in Pennsylvania as early as 1808. The term "lobbying" also appeared in print as early as 1820: Other letters from Washington affirm, that members of the Senate, when the compromise question was to be taken in the House, were not only "lobbying about the Representatives' Chamber" but also active in endeavoring to intimidate certain weak representatives by insulting threats to dissolve the Union. — April 1, 1820 Lobbying by country Since the 1980s, lobbying in Australia has grown from a small industry of a few hundred employees to a multi-billion dollar per year industry. What was once the preserve of big multinational companies and at a more local level (property developers, for example, Urban Taskforce Australia) has morphed into an industry that employs more than 10,000 people and represents every facet of human endeavour. Academic John Warhurst from the Australian National University noted that over this time, retired politicians have increasingly turned political lobbyists to leverage their networks and experience for private gain. In 2018 he noted that two of the top three Howard government ministers had become lobbyists: Alexander Downer and Peter Costello, and that the trend could be traced back to the Hawke government of 1983. Mick Young stated that by 1983 the lobbying profession was an established part of the democratic political process in Canberra. Warhurst attests that by 2018, "political leader-lobbyists" were an established part of the same process. During the 1980s, political leaders traded on their own names, like Bob Hawke, or joined the "respectable" end of the lobbying spectrum, working for law firms or banks, like former New South Wales premiers Nick Greiner and Bob Carr. In 2008, Alexander Downer formed the lobbying firm Bespoke Approach, along with former Labor minister Nick Bolkus and Ian Smith, who is married to former Australian Democrats leader, Natasha Stott-Despoja. Peter Costello carried two former staffers to work with him in his lobbying firm, ECG Consulting: Jonathan Epstein and David Gazard. Politicians can become exposed to allegations of conflicts of interest when they both lobby and advise governments. Examples include Peter Costello. Political party staff often form lobbying firms or dominate their ranks. Former Howard chief-of-staff Grahame Morris is the director of Barton Deakin Government Relations. His colleagues there include David Alexander (former Costello staffer), Sallyanne Atkinson (former Lord Mayor of Brisbane and former federal Liberal Party candidate), Howard staffer John Griffin and former New South Wales Liberal Party leader, Peter Collins. The Labor "sister" company is Hawker Britton, so named as both firms are owned by STW Group. In 2013, Hawker Britton had 113 client companies on its books. In 2013, there were just under 280 firms on the Federal Australian Register of Lobbyists. Steve Carney of Carney Associated said that lobbyists "try to leave no thumbprints on the glass, no footprints in the sand. The best lobbying is when nobody knows you were there." Mark Textor of campaign advisory group Crosby Textor described political lobbying as a "pathetic miserable industry". New state laws which came into operation in South Australia on 1 July 2025, have banned political donations, instead funding parties and candidates with taxpayer funds. The effect of the changes mean that minor parties and independents will be at a disadvantage, while incumbent parties will be well funded to run their campaigns with public money, although the legislation includes provisions such as advance payments to new entrants, who will be entitled to receive donations of up to $5,000 and will also be subject to a spending cap. According to The Australia Institute, around 75 per cent of public funding will go to the major parties, and only 1-2 per cent to new entrants. South Australia's changes have gone further than any other state, and possibly any other country, with this legislation. Supermarket chains in Australia engage lobbying firms with political weight in their ranks. Australian Supermarket giant Coles is represented by both ECG Consulting and Bespoke Approach, while its own parent company, Wesfarmers, has former West Australian premier Alan Carpenter in charge of corporate affairs. Competitor Woolworths has a government relations team composed of former Labor and Liberal advisers, under the direction of a former leader of the National Party, Andrew Hall. Aldi engages GRA (Government Relations Australia), one of Australia's largest lobbying firms, whose staff includes former Federal Labor treasurer, John Dawkins. A register of federal lobbyists is kept by the Australian Government and is accessible to the public via its website. Similar registers for State government lobbyists were introduced between 2007 and 2009 around Australia. Since April 2007 in Western Australia, only lobbyists listed on the state's register are allowed to contact a government representative for the purpose of lobbying. Similar rules have applied in Tasmania since 1 September 2009 and in South Australia and Victoria since 1 December 2009. A criticism of the lobbyist register is that it only captures professional third-party lobbyists, not employees of companies which directly lobby government. An example of this is BHP, which employs Geoff Walsh, a key advisor to Bob Hawke as an in-house lobbyist. In 2022, The Mercury published a complete list of lobbyists registered at the Tasmanian Parliament. The field was dominated by former politicians, advisers and journalists in 2016. Caviar diplomacy is a lobbying strategy of Azerbaijan, consisting of costly invitations and bribes to foreign politicians and employees of international organizations to Azerbaijan at the expense of the host country. Caviar diplomacy also includes expensive gifts presented as "a tribute to the Eastern tradition." In December 2022, Bahrain's lobbying efforts were reflected in a report by The Guardian, which involved the name of a senior Czech MEP Tomáš Zdechovský. The controversy concerned the European Parliament's "friendship groups", the unofficial bodies operating with no formal regulations and sometimes under sponsored lobbyists and foreign governments. The European Parliament was preparing to vote on a resolution to call for the release of a Bahraini political prisoner Abdulhadi al-Khawaja. However, the chair of the European Parliament's Bahrain friendship group, Zdechovský came under question for visiting Bahrain in April 2022, without declaring. In a separate resolution, Zdechovský's EPP failed to call for Khawaja's release and instead called him a "political opponent". Director of BIRD, Sayed Ahmed Alwadaei accused the Czech MEP of acting as a mouthpiece for Bahrain. Canada maintains a Registry of Lobbyists. As of 2018, more than 5,000 people worked as registered lobbyists at Canada's federal level. Lobbying began as an unregulated profession, but since the late 20th century has been regulated by the government to increase transparency and establish a set of ethics for both lobbyists, and those who will be lobbied. Canada does not require disclosure of lobbyist spending on lobbying activities. The first step towards specialized regulation of lobbying in the European Union was a Written Question tabled by Alman Metten, in 1989. In 1991, Marc Galle, Chairman of the Committee on the Rules of Procedure, the Verification of Credentials and Immunities, was appointed to submit proposals for a Code of conduct and a register of lobbyists. Today lobbying in the European Union is an integral and important part of decision-making in the EU. From year to year lobbying regulation in the EU is constantly improving and the number of lobbyists increases. This increase in lobbying activity is a result of the growing recognition of lobbying as a critical discipline at the intersection of politics, economics, and society. In 2003 there were around 15,000 lobbyists (consultants, lawyers, associations, corporations, NGOs etc.) in Brussels seeking to influence the EU's legislation. Some 2,600 special interest groups had a permanent office in Brussels. Their distribution was roughly as follows: European trade federations (32%), consultants (20%), companies (13%), NGOs (11%), national associations (10%), regional representations (6%), international organizations (5%) and think tanks (1%), (Lehmann, 2003, pp iii). In addition to this, lobby organisations sometimes hire former EU employees (a phenomenon known as the revolving door) who possess inside knowledge of the EU institutions and policy process. This practice of hiring former EU employees is part of what lobbyist Andreas Geiger describes as lobbying's vital role in shaping law and decision-making processes, given the unique insights and access these individuals provide. A report by Transparency International EU published in January 2017 analysed the career paths of former EU officials and found that 30% of Members of the European Parliament who left politics went to work for organisations on the EU lobby register after their mandate and approximately one-third of Commissioners serving under Barroso took jobs in the private sector after their mandate, including for Uber, ArcelorMittal, Goldman Sachs and Bank of America Merrill Lynch. These potential conflicts of interest could be avoided if a stronger ethics framework were established at the EU level, including an independent ethics body and longer cooling-off periods for MEPs. In the wake of the Jack Abramoff Indian lobbying scandal in Washington, D.C., and the massive impact this had on the lobbying scene in the United States, the rules for lobbying in the EU—which until now consisted of only a non-binding code of conduct—may also be tightened. Eventually, on 31 January 2019, the European Parliament adopted binding rules on lobby transparency. Amending its Rules of Procedure, the Parliament stipulated that MEPs involved in drafting and negotiating legislation must publish online their meetings with lobbyists. The amendment says that "rapporteurs, shadow rapporteurs or committee chairs shall, for each report, publish online all scheduled meetings with interest representatives falling under the scope of the Transparency Register"- the database of the EU. The European allies were being lobbied by the UAE and Saudi Arabia to regain diplomatic ties with the Syrian government. The two Arab countries lobbied the European Union for months, pushing them to ease the sanctions on Syria for the revival of its collapsed economy. The UAE and its neighbour country argued that without the ease of sanctions, the diplomatic efforts to end the Syrian war would be ineffective. However, the EU nations, including France and Germany, turned down the idea of restoring ties with Syria, stating that it would legitimize the regime that is accused of massacring its own people. There is currently no regulation at all for lobbying activities in France. There is no regulated access to the French institutions and no register specific to France, but there is one for the European Union where French lobbyists are able to register themselves. For example, the internal rule of the National Assembly (art. 23 and 79) forbids members of Parliament to be linked with a particular interest[definition needed]. Also, there is no rule at all for consultation of interest groups by the Parliament and the Government. Nevertheless, a recent parliamentary initiative[which?] (motion for a resolution) has been launched by several MPs[who?] so as to establish a register for representatives of interest groups and lobbyists who intend to lobby the MPs. In Germany, lobbying has existed since 1956, when the Federal Constitutional Court issued a ruling legalizing it. A mandatory lobby register (German: Lobbyliste) was introduced in Germany effective 1 January 2022, along with a code of conduct. These rules were criticized as insufficient by several opposition party members and representatives from the Council of Europe, who argued that they did not adequately address issues of transparency and potential conflicts of interest. Stricter rules were initially scheduled to come into effect on January 1, 2024, however these legal alterations did not come into force until March 1, 2024. Italy does not have lobbying legislation at the national level nowadays, even though there have been proposals by lawmakers over the years. In 2016, the Chamber of Deputies added an addendum that introduced a Regulation of interest representation. The Regulation expired in late 2017, when the term of the sitting Parliament expired. With the rise of the new parliamentary term in 2018, the Regulation was not being readopted. At the subnational level, only six regions have legislations about lobbying: Tuscany (2002), Molise (2004), Abruzzo (2010), Calabria (2016), Lombardy (2016) and Puglia (2017). These regional legislations have similar structure, but only Tuscany took a step forward to implement this legislation and create a public register. In Italy, over the years, lobbies and power groups have obstructed the liberalization of markets and favored the protection of existing privileges. Despite various attempts to promote competition, such as the Law for the Market and Competition passed a year ago, the process has been riddled with delays, amendments and compromises that have weakened the law. Pressure from various lobbies led to the deletion of several important provisions. For example, due to pressure from pharmacists, the sale of Band C drugs in supermarkets and para pharmacies was skipped. Other provisions removed include the portability of pension funds, the sale of boxes or garages worth less than one hundred thousand euros without a notarized deed, the protected energy market, and the Postal Service monopoly. In addition, the rule on RCA tariffs was withdrawn after protests from insurance companies, while the diatribe between taxi drivers and Uber was postponed for a separate measure. Professional associations, such as lawyers and dentists, opposed measures that undermined their interests, such as the requirement for lawyers to have a quote or the requirement that dental companies be at least two-thirds owned by registered members. Other categories, such as hoteliers, called for a ban on Airbnb in the country. The lack of competitive markets is one of the main reasons Italy has not experienced economic growth in recent years. However, pressure groups continue to defend their privileges, hindering economic liberalization. The International Monetary Fund study indicates that true liberalization could grow Italy's GDP in a few years, but lobbies seem to be able to prevent such changes. A 2016 study found evidence of significant indirect lobbying of then-Prime Minister Silvio Berlusconi through business proxies. The authors document a significant pro-Mediaset (the mass media company founded and controlled by Berlusconi) bias in the allocation of advertising spending during Berlusconi's political tenure, in particularly for companies operating in more regulated sectors. Using advertising data from the Nielsen AdEx database, the behavior of companies buying advertising space on Mediaset television channels during Berlusconi's tenure as prime minister was analyzed. It is hypothesized that some companies are more likely to advertise on Mediaset channels when Berlusconi is in power, indicating a potential correlation between advertising behavior and political influence. A model of the Italian television advertising market was developed, distinguishing between regulated firms (interested in government actions) and unregulated firms (less interested in specific public policy changes). The model predicts that advertising prices on Mediaset increase when Berlusconi is in power and that the mix of advertisers on Mediaset channels shifts toward regulated firms during his tenure. To assess the impact of Berlusconi's political influence, industries were ranked according to their regulatory score, obtained from a survey of Italian economists. Highly regulated industries, such as telecommunications, pharmaceuticals, and manufacturing, showed a greater tendency to allocate a portion of their advertising budgets to Mediaset during Berlusconi's tenure. Despite higher prices for advertising space on Mediaset channels during Berlusconi's tenure, companies continued to advertise, suggesting that they expect significant political benefits from supporting the network. Mediaset's advertising partners are estimated to have paid about 1.9 billion euros more during Berlusconi's three terms, indicating the expected political value of their indirect lobbying efforts. This study provides evidence of market-based lobbying, in which companies strategically allocate their advertising budgets to gain political influence. It also highlights the additional conflict of interest that politicians with corporate holdings face and raises important questions about the role of money in politics beyond direct campaign contributions. Another relevant case of lobbying that has been going on for at least 16 years concerns owners of beach establishments. Beaches are the Italian State's properties: since 2022, owners have had to pay a fee of 2698 euros to keep a public concession of a beach establishment. This is an amount of money that would be paid back just by renting for three months 2 beach umbrellas for 15 euros each (and in many cases, the renting prices are higher). The Court of Accounts has declared an imbalance between the fee and the gains from the beach establishment. Until 2009, according to a 1949 law, people who had public concessions had the right to keep them if there was no opposition from third parties. In 2009 this law was abolished under the menace of legal procedure from the EU for infraction of a 2006 directive, that established mandatory public procedures that were impartial and transparent. Anyhow, since then, governments continuously postponed any decision regarding modifying laws on public concessions for beach establishments. Under the government of Mario Draghi, the deadline for all concessions was established for 31 December 2023: anyhow, the new Prime Minister Giorgia Meloni assured in a letter of November 3, 2022, that "their government would defend the families that work in that sector", and delayed the deadline of the concessions. Some politicians claim that the families involved in the issue represent a significant and influential number of electors. Finally, lobbying from taxi drivers represents a growing issue. The current situation in Italy regarding taxi services is regulated by Law No. 21 of 1992. According to this law, the responsibility for determining the number of taxi licenses, shifts, and fares is given to the municipalities. Taxi licenses are held by artisan business owners who have passed a driver's exam and are registered with the Chamber of Commerce. After holding a license for five years, reaching the age of 60, or due to illness, license holders can transfer their license to someone else upon indicating their preference to the municipality. In case of death, the license can be passed to one of the heirs or their designated individuals. Italy has an average of one taxi for every 2,000 inhabitants, whereas countries like France and Spain have ratios of 1,160 and 1,028 taxis per 2,000 inhabitants, respectively. This suggests that Italy has a relatively lower number of taxis available compared to its population. In August 2019, the then Transport Councillor Marco Granelli acknowledged the need to increase the number of taxi licenses by 450 to meet the demand. Data showed that a significant percentage of calls for taxis were going unanswered during peak hours and weekends. However, the issue was put on hold due to the COVID-19 pandemic, and it remains uncertain when it will be addressed. Romanian legislation does not include an express regulation on lobbying activity. The legislative proposals initiated by various parliamentarians have not been finalized. Attempts to regulate lobbying in Romania have appeared in the context of the fight against corruption. Anti-corruption strategies adopted in 2011 and 2004 mentions the purposes of the elaboration of a draft law on lobbying, as well as ensuring transparency in the decision-making activity. In 2008 and 2011, the emphasis was mainly on transparency in the decision-making activity of the public authorities, regulation of lobbying activities no longer appeared as a distinct or expressly mentioned objective. The Romanian Lobby Registry Association (ARRL) was founded in June 2010 to popularize and promote lobbying activity. ARRL is a non-profit legal entity that works under private law. The majority of lobbying companies represent non-governmental organizations which activities include education, ecology, fundamental freedoms, health, consumer rights etc. Other entities that deal with lobby practice are multinational companies, Romanian companies, law firms and specialized lobby firms. In India, where there is no law regulating the process, lobbying has traditionally been a tool for industry bodies like the National Association of Software and Service Companies, the Confederation of Indian Industry, the Federation of Indian Chambers of Commerce and Industry, the Associated Chambers of Commerce and Industry of India and other pressure groups to engage with the government ahead of the national budget and legislation in parliament. Lobbying activities have frequently been identified in the context of corruption cases, for example, the 2010 controversy surrounding leaked audio transcripts of conversations between the corporate lobbyist Niira Radia and senior journalists and politicians. Besides private companies, the Indian government has been paying for the services of a US firm since 2005 to lobby, for example, in relation to the India-US civilian nuclear deal. In India, there are no laws that defined the scope of lobbying, who could undertake it, or the extent of disclosure necessary. Companies are not mandated to disclose their activities and lobbyists are neither authorized nor encouraged to reveal the names of clients or public officials they have contacted. The distinction between lobbying and bribery still remains unclear. In 2012, Walmart revealed it had spent $25 million since 2008 on lobbying to "enhance market access for investment in India". This disclosure came weeks after the Indian government made a controversial decision to permit foreign direct investment in the country's multi-brand retail sector. Successful grassroots lobbying campaigns include the Mazdoor Kisan Shakti Sangathan's campaign to pass the 2005 Right to Information Act and Anna Hazare's anti-corruption campaign to introduce the 2011 Lokpal Bill. There is no register for lobbying activity and no cooling off period for public officials before they can enter the lobbying industry in New Zealand, allowing politicians and Parliamentary staffers to immediately become lobbyists after leaving office. Kris Faafoi joined a lobbying firm just three months after leaving Parliament, where he had been justice and broadcasting minister. Lobbyists also move directly into staffer positions. Gordon-Jon Thompson took a leave of absence from his lobbying firm to work as chief of staff to Prime Minister Jacinda Ardern for four months before returning to his lobbying firm. Andrew Kirton resigned from his lobbying company on 31 January 2023 and the next day was announced as chief of staff for Prime Minister Chris Hipkins. Some ad hoc provisions against revolving door politics exist in relation to certain industries. The Immigration Advisers Licensing Act 2007, for example, prohibits Ministers of Immigration, Associate Ministers of Immigration and immigration officials from becoming a licensed immigration adviser for one year after leaving government employment. Transparency International (TI) criticized the lack of oversight in the New Zealand lobbying industry in a November 2022 report as lax. In the UK, lobbying plays a significant role in the formation of legislation. Various commercial organisations, lobby groups "lobby" for particular policies and decisions by Parliament and other political organs at national, regional and local levels. The phrase "lobbying" comes from the gathering of Members of Parliament and peers in the hallways (or lobbies) of Houses of Parliament before and after parliamentary debates. The now-defunct UK Public Affairs Council (UKPAC) defined lobbying as: in a professional capacity, attempting to influence, or advising those who wish to influence, the UK Government, Parliament, the devolved legislatures or administrations, regional or local government or other public bodies on any matter within their competence. Formal procedures enable individual members of the public to lobby their Member of Parliament but most lobbying activity centres on corporate, charity and trade association lobbying, where organisations seek to amend government policy through advocacy. In the United States, some special interests hire professional advocates to argue for specific legislation in decision-making bodies, such as Congress. Some lobbyists are now using social media to reduce the cost of traditional campaigns, and to more precisely target public officials with political messages. A 2011 study of the 50 firms that spent the most on lobbying relative to their assets compared their financial performance against that of the S&P 500, and concluded that spending on lobbying was a "spectacular investment" yielding "blistering" returns comparable to a high-flying hedge fund, even despite the financial downturn. A 2011 meta-analysis of previous research findings found a positive correlation between corporate political activity and firm performance. A 2009 study found that lobbying brought a return on investment of as much as 22,000% in some cases. Major American corporations spent $345 million lobbying for just three pro-immigration bills between 2006 and 2008. A review of 30 food and beverage companies spent $38.2 million on lobbying in 2020 to strengthen and maintain their influence in Washington, D.C. A study from the Kellogg School of Management found that political donations by corporations do not increase shareholder value. The authors posit a few reasons that firms continue giving despite little returns, including signaling firm values to investors and consumption value for individual managers. Wall Street spent a record $2 billion trying to influence the 2016 United States presidential election. Foreign-funded lobbying efforts include those of Israel, Saudi Arabia, Turkey, Egypt, Pakistan, and China lobbies. In 2010 alone, foreign governments spent approximately $460 million on lobbying members of Congress and government officials. In the US, lobbying for foreign governments is not illegal, but it requires registering as a foreign agent with the Justice Department under the Foreign Agents Registration Act (FARA). Unofficially, according to Politico, 'many lobbyists try to avoid representing countries that have tense relationships with Washington or troubled human rights records'. Between 2015 and 2017, around 145 registered lobbyists were paid $18 million by Saudi Arabia to influence the U.S. government. In January 2017, an order by Donald Trump led to a lifetime ban on administration officials from lobbying for foreign governments and a five-year ban on other forms of lobbying. However, the rule was revoked by Trump right before the end of his presidency. A number of Trump allies were found guilty of lobbying on behalf of foreign governments during the 2016 US elections, including Paul Manafort; Elliott Broidy pleaded guilty in October 2020 to failing to register as a lobbyist for a foreign individual. On January 19, 2021, President Trump granted Mr. Broidy a full and unconditional pardon. The United Arab Emirates has a long history of lobbying government and politicians in the West for its conflict of interest concerning building influence and using it to impact the country's foreign policy. In November 2022 it was accused of hiring PR and lobbying firms in order to promote to the politicians in the United States about its selection to host the COP28 Climate Conference. The problem was that the promotion started even before Egypt hosted 2022's COP27 Climate event. Fleishmann Hillard were hired to compose letters that proposed the idea of Emirati ministers attending conferences and events and using the phrase "the UAE is hosting COP28 next year". Whereas, Akin Gump Strauss Hauer & Feld were hired to reach out to US politicians particularly pushing the environmental policies or favouring fossil fuels in addition to informing them about the UAE hosting COP28. The Gulf nation even declared its intentions of achieving net zero emissions by 2050, even though 30% of their GDP relies on oil and gas directly, while the remaining relies upon industry run on heavy energy consumption. In February 2024, New Westminster Mayor Patrick Johnstone faced scrutiny after attending the COP28 conference. Johnstone's expenses, including the conference fees, travel and accommodation, were incurred by C40 Cities Climate Leadership Group, of which Dubai is a member of the sterling committee. Councillors Daniel Fontaine and Paul Minhas filed a complaint against Johnstone for breaking the state's code of conduct. The investigation was assigned to Commissioner Jennifer Devins, who, in her October 2024 report, stated that Johnstone's trip provided personal benefits, which councillors are restricted from accepting. While Devins did not impose sanctions, she recommended Johnstone to take training on the laws of country. A firm based in UAE, Alasriya Media Consultancy paid $10,000 a former CIA analyst Larry Johnson to run his podcast Counter Currents. The podcast discusses global politics, including a pro-Russian narrative of the Ukraine war and US foreign policy in the Middle East. The contract was signed in May 2024, but was not disclosed in FARA filing until November. The Emirati firm is represented by a Lebanese celebrity journalist, Ghina Amyouni, whose reason for funding the podcast was unclear. In April 2025, a European Microscope for Middle East Affairs report uncovered the UAE’s lobbying scandal in Europe, involving two human rights organizations– the African Meeting for the Defense of Human Rights (RADDHO) and TACUDU for Culture and Development. RADDHO, which claims to advocate for African human rights, accepted bribes from UAE-linked lobbyists to influence its activities. It was accused of aligning with the UAE’s geopolitical agenda under the direction of Abu Dhabi, raising concerns over its neutrality. RADDHO received over half a million euros from the UAE-linked sources to promote negative campaigns against regional rivals, particularly Qatar, while neglecting human rights abuses in the UAE and its allies. TACUDU was also accused of exploiting its UN consultative status and receiving €350,000 from sources linked to the UAE embassy in Geneva to target Qatar through political campaigns. This led to calls for the United Nations Human Rights Council to suspend TACUDU’s consultative status for violating norms expected of NGOs holding UN consultative status. Criticism The ethics and morals involved with legally lobbying or influence peddling are controversial. Lobbying can, at times, be spoken of with contempt, when the implication is that people with inordinate socioeconomic power are corrupting the law in order to serve their own interests. When people who have a duty to act on behalf of others, such as elected officials with a duty to serve their constituents' interests or more broadly the public good, can benefit by shaping the law to serve the interests of some private parties, a conflict of interest exists. Many critiques of lobbying point to the potential for conflicts of interest to lead to agent misdirection or the intentional failure of an agent with a duty to serve an employer, client, or constituent to perform those duties. The failure of government officials to serve the public interest as a consequence of lobbying by special interests who provide benefits to the official is an example of agent misdirection. That is why lobbying is seen as one of the causes of a democratic deficit. Politicians tend to vote against the preferred position of their constituency when there is more special interest money and less attention to politics. See also References Bibliography |
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Contents OpenAI OpenAI is an American artificial intelligence research organization comprising both a non-profit foundation and a controlled for-profit public benefit corporation (PBC), headquartered in San Francisco. It aims to develop "safe and beneficial" artificial general intelligence (AGI), which it defines as "highly autonomous systems that outperform humans at most economically valuable work". OpenAI is widely recognized for its development of the GPT family of large language models, the DALL-E series of text-to-image models, and the Sora series of text-to-video models, which have influenced industry research and commercial applications. Its release of ChatGPT in November 2022 has been credited with catalyzing widespread interest in generative AI. The organization was founded in 2015 in Delaware but evolved a complex corporate structure. As of October 2025, following restructuring approved by California and Delaware regulators, the non-profit OpenAI Foundation holds 26% of the for-profit OpenAI Group PBC, with Microsoft holding 27% and employees/other investors holding 47%. Under its governance arrangements, the OpenAI Foundation holds the authority to appoint the board of the for-profit OpenAI Group PBC, a mechanism designed to align the entity’s strategic direction with the Foundation’s charter. Microsoft previously invested over $13 billion into OpenAI, and provides Azure cloud computing resources. In October 2025, OpenAI conducted a $6.6 billion share sale that valued the company at $500 billion. In 2023 and 2024, OpenAI faced multiple lawsuits for alleged copyright infringement against authors and media companies whose work was used to train some of OpenAI's products. In November 2023, OpenAI's board removed Sam Altman as CEO, citing a lack of confidence in him, but reinstated him five days later following a reconstruction of the board. Throughout 2024, roughly half of then-employed AI safety researchers left OpenAI, citing the company's prominent role in an industry-wide problem. Founding In December 2015, OpenAI was founded as a not for profit organization by Sam Altman, Elon Musk, Ilya Sutskever, Greg Brockman, Trevor Blackwell, Vicki Cheung, Andrej Karpathy, Durk Kingma, John Schulman, Pamela Vagata, and Wojciech Zaremba, with Sam Altman and Elon Musk as the co-chairs. A total of $1 billion in capital was pledged by Sam Altman, Greg Brockman, Elon Musk, Reid Hoffman, Jessica Livingston, Peter Thiel, Amazon Web Services (AWS), and Infosys. However, the actual capital collected significantly lagged pledges. According to company disclosures, only $130 million had been received by 2019. In its founding charter, OpenAI stated an intention to collaborate openly with other institutions by making certain patents and research publicly available, but later restricted access to its most capable models, citing competitive and safety concerns. OpenAI was initially run from Brockman's living room. It was later headquartered at the Pioneer Building in the Mission District, San Francisco. According to OpenAI's charter, its founding mission is "to ensure that artificial general intelligence (AGI)—by which we mean highly autonomous systems that outperform humans at most economically valuable work—benefits all of humanity." Musk and Altman stated in 2015 that they were partly motivated by concerns about AI safety and existential risk from artificial general intelligence. OpenAI stated that "it's hard to fathom how much human-level AI could benefit society", and that it is equally difficult to comprehend "how much it could damage society if built or used incorrectly". The startup also wrote that AI "should be an extension of individual human wills and, in the spirit of liberty, as broadly and evenly distributed as possible", and that "because of AI's surprising history, it's hard to predict when human-level AI might come within reach. When it does, it'll be important to have a leading research institution which can prioritize a good outcome for all over its own self-interest." Co-chair Sam Altman expected a decades-long project that eventually surpasses human intelligence. Brockman met with Yoshua Bengio, one of the "founding fathers" of deep learning, and drew up a list of great AI researchers. Brockman was able to hire nine of them as the first employees in December 2015. OpenAI did not pay AI researchers salaries comparable to those of Facebook or Google. It also did not pay stock options which AI researchers typically get. Nevertheless, OpenAI spent $7 million on its first 52 employees in 2016. OpenAI's potential and mission drew these researchers to the firm; a Google employee said he was willing to leave Google for OpenAI "partly because of the very strong group of people and, to a very large extent, because of its mission." OpenAI co-founder Wojciech Zaremba stated that he turned down "borderline crazy" offers of two to three times his market value to join OpenAI instead. In April 2016, OpenAI released a public beta of "OpenAI Gym", its platform for reinforcement learning research. Nvidia gifted its first DGX-1 supercomputer to OpenAI in August 2016 to help it train larger and more complex AI models with the capability of reducing processing time from six days to two hours. In December 2016, OpenAI released "Universe", a software platform for measuring and training an AI's general intelligence across the world's supply of games, websites, and other applications. Corporate structure In 2019, OpenAI transitioned from non-profit to "capped" for-profit, with the profit being capped at 100 times any investment. According to OpenAI, the capped-profit model allows OpenAI Global, LLC to legally attract investment from venture funds and, in addition, to grant employees stakes in the company. Many top researchers work for Google Brain, DeepMind, or Facebook, which offer equity that a nonprofit would be unable to match. Before the transition, OpenAI was legally required to publicly disclose the compensation of its top employees. The company then distributed equity to its employees and partnered with Microsoft, announcing an investment package of $1 billion into the company. Since then, OpenAI systems have run on an Azure-based supercomputing platform from Microsoft. OpenAI Global, LLC then announced its intention to commercially license its technologies. It planned to spend $1 billion "within five years, and possibly much faster". Altman stated that even a billion dollars may turn out to be insufficient, and that the lab may ultimately need "more capital than any non-profit has ever raised" to achieve artificial general intelligence. The nonprofit, OpenAI, Inc., is the sole controlling shareholder of OpenAI Global, LLC, which, despite being a for-profit company, retains a formal fiduciary responsibility to OpenAI, Inc.'s nonprofit charter. A majority of OpenAI, Inc.'s board is barred from having financial stakes in OpenAI Global, LLC. In addition, minority members with a stake in OpenAI Global, LLC are barred from certain votes due to conflict of interest. Some researchers have argued that OpenAI Global, LLC's switch to for-profit status is inconsistent with OpenAI's claims to be "democratizing" AI. On February 29, 2024, Elon Musk filed a lawsuit against OpenAI and CEO Sam Altman, accusing them of shifting focus from public benefit to profit maximization—a case OpenAI dismissed as "incoherent" and "frivolous," though Musk later revived legal action against Altman and others in August. On April 9, 2024, OpenAI countersued Musk in federal court, alleging that he had engaged in "bad-faith tactics" to slow the company's progress and seize its innovations for his personal benefit. OpenAI also argued that Musk had previously supported the creation of a for-profit structure and had expressed interest in controlling OpenAI himself. The countersuit seeks damages and legal measures to prevent further alleged interference. On February 10, 2025, a consortium of investors led by Elon Musk submitted a $97.4 billion unsolicited bid to buy the nonprofit that controls OpenAI, declaring willingness to match or exceed any better offer. The offer was rejected on 14 February 2025, with OpenAI stating that it was not for sale, but the offer complicated Altman's restructuring plan by suggesting a lower bar for how much the nonprofit should be valued. OpenAI, Inc. was originally designed as a nonprofit in order to ensure that AGI "benefits all of humanity" rather than "the private gain of any person". In 2019, it created OpenAI Global, LLC, a capped-profit subsidiary controlled by the nonprofit. In December 2024, OpenAI proposed a restructuring plan to convert the capped-profit into a Delaware-based public benefit corporation (PBC), and to release it from the control of the nonprofit. The nonprofit would sell its control and other assets, getting equity in return, and would use it to fund and pursue separate charitable projects, including in science and education. OpenAI's leadership described the change as necessary to secure additional investments, and claimed that the nonprofit's founding mission to ensure AGI "benefits all of humanity" would be better fulfilled. The plan has been criticized by former employees. A legal letter named "Not For Private Gain" asked the attorneys general of California and Delaware to intervene, stating that the restructuring is illegal and would remove governance safeguards from the nonprofit and the attorneys general. The letter argues that OpenAI's complex structure was deliberately designed to remain accountable to its mission, without the conflicting pressure of maximizing profits. It contends that the nonprofit is best positioned to advance its mission of ensuring AGI benefits all of humanity by continuing to control OpenAI Global, LLC, whatever the amount of equity that it could get in exchange. PBCs can choose how they balance their mission with profit-making. Controlling shareholders have a large influence on how closely a PBC sticks to its mission. On October 28, 2025, OpenAI announced that it had adopted the new PBC corporate structure after receiving approval from the attorneys general of California and Delaware. Under the new structure, OpenAI's for-profit branch became a public benefit corporation known as OpenAI Group PBC, while the non-profit was renamed to the OpenAI Foundation. The OpenAI Foundation holds a 26% stake in the PBC, while Microsoft holds a 27% stake and the remaining 47% is owned by employees and other investors. All members of the OpenAI Group PBC board of directors will be appointed by the OpenAI Foundation, which can remove them at any time. Members of the Foundation's board will also serve on the for-profit board. The new structure allows the for-profit PBC to raise investor funds like most traditional tech companies, including through an initial public offering, which Altman claimed was the most likely path forward. In January 2023, OpenAI Global, LLC was in talks for funding that would value the company at $29 billion, double its 2021 value. On January 23, 2023, Microsoft announced a new US$10 billion investment in OpenAI Global, LLC over multiple years, partially needed to use Microsoft's cloud-computing service Azure. From September to December, 2023, Microsoft rebranded all variants of its Copilot to Microsoft Copilot, and they added MS-Copilot to many installations of Windows and released Microsoft Copilot mobile apps. Following OpenAI's 2025 restructuring, Microsoft owns a 27% stake in the for-profit OpenAI Group PBC, valued at $135 billion. In a deal announced the same day, OpenAI agreed to purchase $250 billion of Azure services, with Microsoft ceding their right of first refusal over OpenAI's future cloud computing purchases. As part of the deal, OpenAI will continue to share 20% of its revenue with Microsoft until it achieves AGI, which must now be verified by an independent panel of experts. The deal also loosened restrictions on both companies working with third parties, allowing Microsoft to pursue AGI independently and allowing OpenAI to develop products with other companies. In 2017, OpenAI spent $7.9 million, a quarter of its functional expenses, on cloud computing alone. In comparison, DeepMind's total expenses in 2017 were $442 million. In the summer of 2018, training OpenAI's Dota 2 bots required renting 128,000 CPUs and 256 GPUs from Google for multiple weeks. In October 2024, OpenAI completed a $6.6 billion capital raise with a $157 billion valuation including investments from Microsoft, Nvidia, and SoftBank. On January 21, 2025, Donald Trump announced The Stargate Project, a joint venture between OpenAI, Oracle, SoftBank and MGX to build an AI infrastructure system in conjunction with the US government. The project takes its name from OpenAI's existing "Stargate" supercomputer project and is estimated to cost $500 billion. The partners planned to fund the project over the next four years. In July, the United States Department of Defense announced that OpenAI had received a $200 million contract for AI in the military, along with Anthropic, Google, and xAI. In the same month, the company made a deal with the UK Government to use ChatGPT and other AI tools in public services. OpenAI subsequently began a $50 million fund to support nonprofit and community organizations. In April 2025, OpenAI raised $40 billion at a $300 billion post-money valuation, which was the highest-value private technology deal in history. The financing round was led by SoftBank, with other participants including Microsoft, Coatue, Altimeter and Thrive. In July 2025, the company reported annualized revenue of $12 billion. This was an increase from $3.7 billion in 2024, which was driven by ChatGPT subscriptions, which reached 20 million paid subscribers by April 2025, up from 15.5 million at the end of 2024, alongside a rapidly expanding enterprise customer base that grew to five million business users. The company’s cash burn remains high because of the intensive computational costs required to train and operate large language models. It projects an $8 billion operating loss in 2025. OpenAI reports revised long-term spending projections totaling approximately $115 billion through 2029, with annual expenditures projected to escalate significantly, reaching $17 billion in 2026, $35 billion in 2027, and $45 billion in 2028. These expenditures are primarily allocated toward expanding compute infrastructure, developing proprietary AI chips, constructing data centers, and funding intensive model training programs, with more than half of the spending through the end of the decade expected to support research-intensive compute for model training and development. The company's financial strategy prioritizes market expansion and technological advancement over near-term profitability, with OpenAI targeting cash-flow-positive operations by 2029 and projecting revenue of approximately $200 billion by 2030. This aggressive spending trajectory underscores both the enormous capital requirements of scaling cutting-edge AI technology and OpenAI's commitment to maintaining its position as a leader in the artificial intelligence industry. In October 2025, OpenAI completed an employee share sale of up to $10 billion to existing investors which valued the company at $500 billion. The deal values OpenAI as the most valuable privately owned company in the world—surpassing SpaceX as the world's most valuable private company. On November 17, 2023, Sam Altman was removed as CEO when its board of directors (composed of Helen Toner, Ilya Sutskever, Adam D'Angelo and Tasha McCauley) cited a lack of confidence in him. Chief Technology Officer Mira Murati took over as interim CEO. Greg Brockman, the president of OpenAI, was also removed as chairman of the board and resigned from the company's presidency shortly thereafter. Three senior OpenAI researchers subsequently resigned: director of research and GPT-4 lead Jakub Pachocki, head of AI risk Aleksander Mądry, and researcher Szymon Sidor. On November 18, 2023, there were reportedly talks of Altman returning as CEO amid pressure placed upon the board by investors such as Microsoft and Thrive Capital, who objected to Altman's departure. Although Altman himself spoke in favor of returning to OpenAI, he has since stated that he considered starting a new company and bringing former OpenAI employees with him if talks to reinstate him didn't work out. The board members agreed "in principle" to resign if Altman returned. On November 19, 2023, negotiations with Altman to return failed and Murati was replaced by Emmett Shear as interim CEO. The board initially contacted Anthropic CEO Dario Amodei (a former OpenAI executive) about replacing Altman, and proposed a merger of the two companies, but both offers were declined. On November 20, 2023, Microsoft CEO Satya Nadella announced Altman and Brockman would be joining Microsoft to lead a new advanced AI research team, but added that they were still committed to OpenAI despite recent events. Before the partnership with Microsoft was finalized, Altman gave the board another opportunity to negotiate with him. About 738 of OpenAI's 770 employees, including Murati and Sutskever, signed an open letter stating they would quit their jobs and join Microsoft if the board did not rehire Altman and then resign. This prompted OpenAI investors to consider legal action against the board as well. In response, OpenAI management sent an internal memo to employees stating that negotiations with Altman and the board had resumed and would take some time. On November 21, 2023, after continued negotiations, Altman and Brockman returned to the company in their prior roles along with a reconstructed board made up of new members Bret Taylor (as chairman) and Lawrence Summers, with D'Angelo remaining. According to subsequent reporting, shortly before Altman’s firing, some employees raised concerns to the board about how he had handled the safety implications of a recent internal AI capability discovery. On November 29, 2023, OpenAI announced that an anonymous Microsoft employee had joined the board as a non-voting member to observe the company's operations; Microsoft resigned from the board in July 2024. In February 2024, the Securities and Exchange Commission subpoenaed OpenAI's internal communication to determine if Altman's alleged lack of candor misled investors. In 2024, following the temporary removal of Sam Altman and his return, many employees gradually left OpenAI, including most of the original leadership team and a significant number of AI safety researchers. In August 2023, it was announced that OpenAI had acquired the New York-based start-up Global Illumination, a company that deploys AI to develop digital infrastructure and creative tools. In June 2024, OpenAI acquired Multi, a startup focused on remote collaboration. In March 2025, OpenAI reached a deal with CoreWeave to acquire $350 million worth of CoreWeave shares and access to AI infrastructure, in return for $11.9 billion paid over five years. Microsoft was already CoreWeave's biggest customer in 2024. Alongside their other business dealings, OpenAI and Microsoft were renegotiating the terms of their partnership to facilitate a potential future initial public offering by OpenAI, while ensuring Microsoft's continued access to advanced AI models. On May 21, OpenAI announced the $6.5 billion acquisition of io, an AI hardware start-up founded by former Apple designer Jony Ive in 2024. In September 2025, OpenAI agreed to acquire the product testing startup Statsig for $1.1 billion in an all-stock deal and appointed Statsig's founding CEO Vijaye Raji as OpenAI's chief technology officer of applications. The company also announced development of an AI-driven hiring service designed to rival LinkedIn. OpenAI acquired personal finance app Roi in October 2025. In October 2025, OpenAI acquired Software Applications Incorporated, the developer of Sky, a macOS-based natural language interface designed to operate across desktop applications. The Sky team joined OpenAI, and the company announced plans to integrate Sky’s capabilities into ChatGPT. In December 2025, it was announced OpenAI had agreed to acquire Neptune, an AI tooling startup that helps companies track and manage model training, for an undisclosed amount. In January 2026, it was announced OpenAI had acquired healthcare technology startup Torch for approximately $60 million. The acquisition followed the launch of OpenAI’s ChatGPT Health product and was intended to strengthen the company’s medical data and healthcare artificial intelligence capabilities. OpenAI has been criticized for outsourcing the annotation of data sets to Sama, a company based in San Francisco that employed workers in Kenya. These annotations were used to train an AI model to detect toxicity, which could then be used to moderate toxic content, notably from ChatGPT's training data and outputs. However, these pieces of text usually contained detailed descriptions of various types of violence, including sexual violence. The investigation uncovered that OpenAI began sending snippets of data to Sama as early as November 2021. The four Sama employees interviewed by Time described themselves as mentally scarred. OpenAI paid Sama $12.50 per hour of work, and Sama was redistributing the equivalent of between $1.32 and $2.00 per hour post-tax to its annotators. Sama's spokesperson said that the $12.50 was also covering other implicit costs, among which were infrastructure expenses, quality assurance and management. In 2024, OpenAI began collaborating with Broadcom to design a custom AI chip capable of both training and inference, targeted for mass production in 2026 and to be manufactured by TSMC on a 3 nm process node. This initiative intended to reduce OpenAI's dependence on Nvidia GPUs, which are costly and face high demand in the market. In January 2024, Arizona State University purchased ChatGPT Enterprise in OpenAI's first deal with a university. In June 2024, Apple Inc. signed a contract with OpenAI to integrate ChatGPT features into its products as part of its new Apple Intelligence initiative. In June 2025, OpenAI began renting Google Cloud's Tensor Processing Units (TPUs) to support ChatGPT and related services, marking its first meaningful use of non‑Nvidia AI chips. In September 2025, it was revealed that OpenAI signed a contract with Oracle to purchase $300 billion in computing power over the next five years. In September 2025, OpenAI and NVIDIA announced a memorandum of understanding that included a potential deployment of at least 10 gigawatts of NVIDIA systems and a $100 billion investment from NVIDIA in OpenAI. OpenAI expected the negotiations to be completed within weeks. As of January 2026, this has not been realized, and the two sides are rethinking the future of their partnership. In October 2025, OpenAI announced a multi-billion dollar deal with AMD. OpenAI committed to purchasing six gigawatts worth of AMD chips, starting with the MI450. OpenAI will have the option to buy up to 160 million shares of AMD, about 10% of the company, depending on development, performance and share price targets. In December 2025, Disney said it would make a $1 billion investment in OpenAI, and signed a three-year licensing deal that will let users generate videos using Sora—OpenAI's short-form AI video platform. More than 200 Disney, Marvel, Star Wars and Pixar characters will be available to OpenAI users. In early 2026, Amazon entered advanced discussions to invest up to $50 billion in OpenAI as part of a potential artificial intelligence partnership. Under the proposed agreement, OpenAI’s models could be integrated into Amazon’s digital assistant Alexa and other internal projects. OpenAI provides LLMs to the Artificial Intelligence Cyber Challenge and to the Advanced Research Projects Agency for Health. In October 2024, The Intercept revealed that OpenAI's tools are considered "essential" for AFRICOM's mission and included in an "Exception to Fair Opportunity" contractual agreement between the United States Department of Defense and Microsoft. In December 2024, OpenAI said it would partner with defense-tech company Anduril to build drone defense technologies for the United States and its allies. In 2025, OpenAI's Chief Product Officer, Kevin Weil, was commissioned lieutenant colonel in the U.S. Army to join Detachment 201 as senior advisor. In June 2025, the U.S. Department of Defense awarded OpenAI a $200 million one-year contract to develop AI tools for military and national security applications. OpenAI announced a new program, OpenAI for Government, to give federal, state, and local governments access to its models, including ChatGPT. Services In February 2019, GPT-2 was announced, which gained attention for its ability to generate human-like text. In 2020, OpenAI announced GPT-3, a language model trained on large internet datasets. GPT-3 is aimed at natural language answering questions, but it can also translate between languages and coherently generate improvised text. It also announced that an associated API, named the API, would form the heart of its first commercial product. Eleven employees left OpenAI, mostly between December 2020 and January 2021, in order to establish Anthropic. In 2021, OpenAI introduced DALL-E, a specialized deep learning model adept at generating complex digital images from textual descriptions, utilizing a variant of the GPT-3 architecture. In December 2022, OpenAI received widespread media coverage after launching a free preview of ChatGPT, its new AI chatbot based on GPT-3.5. According to OpenAI, the preview received over a million signups within the first five days. According to anonymous sources cited by Reuters in December 2022, OpenAI Global, LLC was projecting $200 million of revenue in 2023 and $1 billion in revenue in 2024. After ChatGPT was launched, Google announced a similar chatbot, Bard, amid internal concerns that ChatGPT could threaten Google’s position as a primary source of online information. On February 7, 2023, Microsoft announced that it was building AI technology based on the same foundation as ChatGPT into Microsoft Bing, Edge, Microsoft 365 and other products. On March 14, 2023, OpenAI released GPT-4, both as an API (with a waitlist) and as a feature of ChatGPT Plus. On November 6, 2023, OpenAI launched GPTs, allowing individuals to create customized versions of ChatGPT for specific purposes, further expanding the possibilities of AI applications across various industries. On November 14, 2023, OpenAI announced they temporarily suspended new sign-ups for ChatGPT Plus due to high demand. Access for newer subscribers re-opened a month later on December 13. In December 2024, the company launched the Sora model. It also launched OpenAI o1, an early reasoning model that was internally codenamed strawberry. Additionally, ChatGPT Pro—a $200/month subscription service offering unlimited o1 access and enhanced voice features—was introduced, and preliminary benchmark results for the upcoming OpenAI o3 models were shared. On January 23, 2025, OpenAI released Operator, an AI agent and web automation tool for accessing websites to execute goals defined by users. The feature was only available to Pro users in the United States. OpenAI released deep research agent, nine days later. It scored a 27% accuracy on the benchmark Humanity's Last Exam (HLE). Altman later stated GPT-4.5 would be the last model without full chain-of-thought reasoning. In July 2025, reports indicated that AI models by both OpenAI and Google DeepMind solved mathematics problems at the level of top-performing students in the International Mathematical Olympiad. OpenAI's large language model was able to achieve gold medal-level performance, reflecting significant progress in AI's reasoning abilities. On October 6, 2025, OpenAI unveiled its Agent Builder platform during the company's DevDay event. The platform includes a visual drag-and-drop interface that lets developers and businesses design, test, and deploy agentic workflows with limited coding. On October 21, 2025, OpenAI introduced ChatGPT Atlas, a browser integrating the ChatGPT assistant directly into web navigation, to compete with existing browsers such as Google Chrome and Apple Safari. On December 11, 2025, OpenAI announced GPT-5.2. This model will be better at creating spreadsheets, building presentations, perceiving images, writing code and understanding long context. On January 27, 2026, OpenAI introduced Prism, a LaTeX-native workspace meant to assist scientists to help with research and writing. The platform utilizes GPT-5.2 as a backend to automate the process of drafting for scientific papers, including features for managing citations, complex equation formatting, and real-time collaborative editing. In March 2023, the company was criticized for disclosing particularly few technical details about products like GPT-4, contradicting its initial commitment to openness and making it harder for independent researchers to replicate its work and develop safeguards. OpenAI cited competitiveness and safety concerns to justify this repudiation. OpenAI's former chief scientist Ilya Sutskever argued in 2023 that open-sourcing increasingly capable models was increasingly risky, and that the safety reasons for not open-sourcing the most potent AI models would become "obvious" in a few years. In September 2025, OpenAI published a study on how people use ChatGPT for everyday tasks. The study found that "non-work tasks" (according to an LLM-based classifier) account for more than 72 percent of all ChatGPT usage, with a minority of overall usage related to business productivity. In July 2023, OpenAI launched the superalignment project, aiming within four years to determine how to align future superintelligent systems. OpenAI promised to dedicate 20% of its computing resources to the project, although the team denied receiving anything close to 20%. OpenAI ended the project in May 2024 after its co-leaders Ilya Sutskever and Jan Leike left the company. In August 2025, OpenAI was criticized after thousands of private ChatGPT conversations were inadvertently exposed to public search engines like Google due to an experimental "share with search engines" feature. The opt-in toggle, intended to allow users to make specific chats discoverable, resulted in some discussions including personal details such as names, locations, and intimate topics appearing in search results when users accidentally enabled it while sharing links. OpenAI announced the feature's permanent removal on August 1, 2025, and the company began coordinating with search providers to remove the exposed content, emphasizing that it was not a security breach but a design flaw that heightened privacy risks. CEO Sam Altman acknowledged the issue in a podcast, noting users often treat ChatGPT as a confidant for deeply personal matters, which amplified concerns about AI handling sensitive data. Management In 2018, Musk resigned from his Board of Directors seat, citing "a potential future conflict [of interest]" with his role as CEO of Tesla due to Tesla's AI development for self-driving cars. OpenAI stated that Musk's financial contributions were below $45 million. On March 3, 2023, Reid Hoffman resigned from his board seat, citing a desire to avoid conflicts of interest with his investments in AI companies via Greylock Partners, and his co-founding of the AI startup Inflection AI. Hoffman remained on the board of Microsoft, a major investor in OpenAI. In May 2024, Chief Scientist Ilya Sutskever resigned and was succeeded by Jakub Pachocki. Co-leader Jan Leike also departed amid concerns over safety and trust. OpenAI then signed deals with Reddit, News Corp, Axios, and Vox Media. Paul Nakasone then joined the board of OpenAI. In August 2024, cofounder John Schulman left OpenAI to join Anthropic, and OpenAI's president Greg Brockman took extended leave until November. In September 2024, CTO Mira Murati left the company. In November 2025, Lawrence Summers resigned from the board of directors. Governance and legal issues In May 2023, Sam Altman, Greg Brockman and Ilya Sutskever posted recommendations for the governance of superintelligence. They stated that superintelligence could happen within the next 10 years, allowing a "dramatically more prosperous future" and that "given the possibility of existential risk, we can't just be reactive". They proposed creating an international watchdog organization similar to IAEA to oversee AI systems above a certain capability threshold, suggesting that relatively weak AI systems on the other side should not be overly regulated. They also called for more technical safety research for superintelligences, and asked for more coordination, for example through governments launching a joint project which "many current efforts become part of". In July 2023, the FTC issued a civil investigative demand to OpenAI to investigate whether the company's data security and privacy practices to develop ChatGPT were unfair or harmed consumers (including by reputational harm) in violation of Section 5 of the Federal Trade Commission Act of 1914. These are typically preliminary investigative matters and are nonpublic, but the FTC's document was leaked. In July 2023, the FTC launched an investigation into OpenAI over allegations that the company scraped public data and published false and defamatory information. They asked OpenAI for comprehensive information about its technology and privacy safeguards, as well as any steps taken to prevent the recurrence of situations in which its chatbot generated false and derogatory content about people. The agency also raised concerns about ‘circular’ spending arrangements—for example, Microsoft extending Azure credits to OpenAI while both companies shared engineering talent—and warned that such structures could negatively affect the public. In September 2024, OpenAI's global affairs chief endorsed the UK's "smart" AI regulation during testimony to a House of Lords committee. In February 2025, OpenAI CEO Sam Altman stated that the company is interested in collaborating with the People's Republic of China, despite regulatory restrictions imposed by the U.S. government. This shift comes in response to the growing influence of the Chinese artificial intelligence company DeepSeek, which has disrupted the AI market with open models, including DeepSeek V3 and DeepSeek R1. Following DeepSeek's market emergence, OpenAI enhanced security protocols to protect proprietary development techniques from industrial espionage. Some industry observers noted similarities between DeepSeek's model distillation approach and OpenAI's methodology, though no formal intellectual property claim was filed. According to Oliver Roberts, in March 2025, the United States had 781 state AI bills or laws. OpenAI advocated for preempting state AI laws with federal laws. According to Scott Kohler, OpenAI has opposed California's AI legislation and suggested that the state bill encroaches on a more competent federal government. Public Citizen opposed a federal preemption on AI and pointed to OpenAI's growth and valuation as evidence that existing state laws have not hampered innovation. Before May 2024, OpenAI required departing employees to sign a lifelong non-disparagement agreement forbidding them from criticizing OpenAI and acknowledging the existence of the agreement. Daniel Kokotajlo, a former employee, publicly stated that he forfeited his vested equity in OpenAI in order to leave without signing the agreement. Sam Altman stated that he was unaware of the equity cancellation provision, and that OpenAI never enforced it to cancel any employee's vested equity. However, leaked documents and emails refute this claim. On May 23, 2024, OpenAI sent a memo releasing former employees from the agreement. OpenAI was sued for copyright infringement by authors Sarah Silverman, Matthew Butterick, Paul Tremblay and Mona Awad in July 2023. In September 2023, 17 authors, including George R. R. Martin, John Grisham, Jodi Picoult and Jonathan Franzen, joined the Authors Guild in filing a class action lawsuit against OpenAI, alleging that the company's technology was illegally using their copyrighted work. The New York Times also sued the company in late December 2023. In May 2024 it was revealed that OpenAI had destroyed its Books1 and Books2 training datasets, which were used in the training of GPT-3, and which the Authors Guild believed to have contained over 100,000 copyrighted books. In 2021, OpenAI developed a speech recognition tool called Whisper. OpenAI used it to transcribe more than one million hours of YouTube videos into text for training GPT-4. The automated transcription of YouTube videos raised concerns within OpenAI employees regarding potential violations of YouTube's terms of service, which prohibit the use of videos for applications independent of the platform, as well as any type of automated access to its videos. Despite these concerns, the project proceeded with notable involvement from OpenAI's president, Greg Brockman. The resulting dataset proved instrumental in training GPT-4. In February 2024, The Intercept as well as Raw Story and Alternate Media Inc. filed lawsuit against OpenAI on copyright litigation ground. The lawsuit is said to have charted a new legal strategy for digital-only publishers to sue OpenAI. On April 30, 2024, eight newspapers filed a lawsuit in the Southern District of New York against OpenAI and Microsoft, claiming illegal harvesting of their copyrighted articles. The suing publications included The Mercury News, The Denver Post, The Orange County Register, St. Paul Pioneer Press, Chicago Tribune, Orlando Sentinel, Sun Sentinel, and New York Daily News. In June 2023, a lawsuit claimed that OpenAI scraped 300 billion words online without consent and without registering as a data broker. It was filed in San Francisco, California, by sixteen anonymous plaintiffs. They also claimed that OpenAI and its partner as well as customer Microsoft continued to unlawfully collect and use personal data from millions of consumers worldwide to train artificial intelligence models. On May 22, 2024, OpenAI entered into an agreement with News Corp to integrate news content from The Wall Street Journal, the New York Post, The Times, and The Sunday Times into its AI platform. Meanwhile, other publications like The New York Times chose to sue OpenAI and Microsoft for copyright infringement over the use of their content to train AI models. In November 2024, a coalition of Canadian news outlets, including the Toronto Star, Metroland Media, Postmedia, The Globe and Mail, The Canadian Press and CBC, sued OpenAI for using their news articles to train its software without permission. In October 2024 during a New York Times interview, Suchir Balaji accused OpenAI of violating copyright law in developing its commercial LLMs which he had helped engineer. He was a likely witness in a major copyright trial against the AI company, and was one of several of its current or former employees named in court filings as potentially having documents relevant to the case. On November 26, 2024, Balaji died by suicide. His death prompted the circulation of conspiracy theories alleging that he had been deliberately silenced. California Congressman Ro Khanna endorsed calls for an investigation. On April 24, 2025, Ziff Davis sued OpenAI in Delaware federal court for copyright infringement. Ziff Davis is known for publications such as ZDNet, PCMag, CNET, IGN and Lifehacker. In April 2023, the EU's European Data Protection Board (EDPB) formed a dedicated task force on ChatGPT "to foster cooperation and to exchange information on possible enforcement actions conducted by data protection authorities" based on the "enforcement action undertaken by the Italian data protection authority against OpenAI about the ChatGPT service". In late April 2024 NOYB filed a complaint with the Austrian Datenschutzbehörde against OpenAI for violating the European General Data Protection Regulation. A text created with ChatGPT gave a false date of birth for a living person without giving the individual the option to see the personal data used in the process. A request to correct the mistake was denied. Additionally, neither the recipients of ChatGPT's work nor the sources used, could be made available, OpenAI claimed. OpenAI was criticized for lifting its ban on using ChatGPT for "military and warfare". Up until January 10, 2024, its "usage policies" included a ban on "activity that has high risk of physical harm, including", specifically, "weapons development" and "military and warfare". Its new policies prohibit "[using] our service to harm yourself or others" and to "develop or use weapons". In August 2025, the parents of a 16-year-old boy who died by suicide filed a wrongful death lawsuit against OpenAI (and CEO Sam Altman), alleging that months of conversations with ChatGPT about mental health and methods of self-harm contributed to their son's death and that safeguards were inadequate for minors. OpenAI expressed condolences and said it was strengthening protections (including updated crisis response behavior and parental controls). Coverage described it as a first-of-its-kind wrongful death case targeting the company's chatbot. The complaint was filed in California state court in San Francisco. In November 2025, the Social Media Victims Law Center and Tech Justice Law Project filed seven lawsuits against OpenAI, of which four lawsuits alleged wrongful death. The suits were filed on behalf of Zane Shamblin, 23, of Texas; Amaurie Lacey, 17, of Georgia; Joshua Enneking, 26, of Florida; and Joe Ceccanti, 48, of Oregon, who each committed suicide after prolonged ChatGPT usage. In December 2025, Stein-Erik Soelberg, who was 56 years old at the time, allegedly murdered his mother Suzanne Adams. In the months prior the paranoid, delusional man often discussed his ideas with ChatGPT. Adam's estate then sued OpenAI claiming that the company shared responsibility due to the risk of chatbot psychosis despite the fact that chatbot psychosis is not a real medical diagnosis. OpenAI responded saying they will make ChatGPT safer for users disconnected from reality. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Python_(programming_language)#cite_ref-37] | [TOKENS: 4314] |
Contents Python (programming language) Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically type-checked and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language. Python 3.0, released in 2008, was a major revision and not completely backward-compatible with earlier versions. Beginning with Python 3.5, capabilities and keywords for typing were added to the language, allowing optional static typing. As of 2026[update], the Python Software Foundation supports Python 3.10, 3.11, 3.12, 3.13, and 3.14, following the project's annual release cycle and five-year support policy. Python 3.15 is currently in the alpha development phase, and the stable release is expected to come out in October 2026. Earlier versions in the 3.x series have reached end-of-life and no longer receive security updates. Python has gained widespread use in the machine learning community. It is widely taught as an introductory programming language. Since 2003, Python has consistently ranked in the top ten of the most popular programming languages in the TIOBE Programming Community Index, which ranks based on searches in 24 platforms. History Python was conceived in the late 1980s by Guido van Rossum at Centrum Wiskunde & Informatica (CWI) in the Netherlands. It was designed as a successor to the ABC programming language, which was inspired by SETL, capable of exception handling and interfacing with the Amoeba operating system. Python implementation began in December 1989. Van Rossum first released it in 1991 as Python 0.9.0. Van Rossum assumed sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from responsibilities as Python's "benevolent dictator for life" (BDFL); this title was bestowed on him by the Python community to reflect his long-term commitment as the project's chief decision-maker. (He has since come out of retirement and is self-titled "BDFL-emeritus".) In January 2019, active Python core developers elected a five-member Steering Council to lead the project. The name Python derives from the British comedy series Monty Python's Flying Circus. (See § Naming.) Python 2.0 was released on 16 October 2000, featuring many new features such as list comprehensions, cycle-detecting garbage collection, reference counting, and Unicode support. Python 2.7's end-of-life was initially set for 2015, and then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python 3. It no longer receives security patches or updates. While Python 2.7 and older versions are officially unsupported, a different unofficial Python implementation, PyPy, continues to support Python 2, i.e., "2.7.18+" (plus 3.11), with the plus signifying (at least some) "backported security updates". Python 3.0 was released on 3 December 2008, and was a major revision and not completely backward-compatible with earlier versions, with some new semantics and changed syntax. Python 2.7.18, released in 2020, was the last release of Python 2. Several releases in the Python 3.x series have added new syntax to the language, and made a few (considered very minor) backward-incompatible changes. As of January 2026[update], Python 3.14.3 is the latest stable release. All older 3.x versions had a security update down to Python 3.9.24 then again with 3.9.25, the final version in 3.9 series. Python 3.10 is, since November 2025, the oldest supported branch. Python 3.15 has an alpha released, and Android has an official downloadable executable available for Python 3.14. Releases receive two years of full support followed by three years of security support. Design philosophy and features Python is a multi-paradigm programming language. Object-oriented programming and structured programming are fully supported, and many of their features support functional programming and aspect-oriented programming – including metaprogramming and metaobjects. Many other paradigms are supported via extensions, including design by contract and logic programming. Python is often referred to as a 'glue language' because it is purposely designed to be able to integrate components written in other languages. Python uses dynamic typing and a combination of reference counting and a cycle-detecting garbage collector for memory management. It uses dynamic name resolution (late binding), which binds method and variable names during program execution. Python's design offers some support for functional programming in the "Lisp tradition". It has filter, map, and reduce functions; list comprehensions, dictionaries, sets, and generator expressions. The standard library has two modules (itertools and functools) that implement functional tools borrowed from Haskell and Standard ML. Python's core philosophy is summarized in the Zen of Python (PEP 20) written by Tim Peters, which includes aphorisms such as these: However, Python has received criticism for violating these principles and adding unnecessary language bloat. Responses to these criticisms note that the Zen of Python is a guideline rather than a rule. The addition of some new features had been controversial: Guido van Rossum resigned as Benevolent Dictator for Life after conflict about adding the assignment expression operator in Python 3.8. Nevertheless, rather than building all functionality into its core, Python was designed to be highly extensible via modules. This compact modularity has made it particularly popular as a means of adding programmable interfaces to existing applications. Van Rossum's vision of a small core language with a large standard library and easily extensible interpreter stemmed from his frustrations with ABC, which represented the opposite approach. Python claims to strive for a simpler, less-cluttered syntax and grammar, while giving developers a choice in their coding methodology. Python lacks do .. while loops, which Rossum considered harmful. In contrast to Perl's motto "there is more than one way to do it", Python advocates an approach where "there should be one – and preferably only one – obvious way to do it". In practice, however, Python provides many ways to achieve a given goal. There are at least three ways to format a string literal, with no certainty as to which one a programmer should use. Alex Martelli is a Fellow at the Python Software Foundation and Python book author; he wrote that "To describe something as 'clever' is not considered a compliment in the Python culture." Python's developers typically prioritize readability over performance. For example, they reject patches to non-critical parts of the CPython reference implementation that would offer increases in speed that do not justify the cost of clarity and readability.[failed verification] Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as C, or by using a just-in-time compiler like PyPy. Also, it is possible to transpile to other languages. However, this approach either fails to achieve the expected speed-up, since Python is a very dynamic language, or only a restricted subset of Python is compiled (with potential minor semantic changes). Python is meant to be a fun language to use. This goal is reflected in the name – a tribute to the British comedy group Monty Python – and in playful approaches to some tutorials and reference materials. For instance, some code examples use the terms "spam" and "eggs" (in reference to a Monty Python sketch), rather than the typical terms "foo" and "bar". A common neologism in the Python community is pythonic, which has a broad range of meanings related to program style: Pythonic code may use Python idioms well; be natural or show fluency in the language; or conform with Python's minimalist philosophy and emphasis on readability. Syntax and semantics Python is meant to be an easily readable language. Its formatting is visually uncluttered and often uses English keywords where other languages use punctuation. Unlike many other languages, it does not use curly brackets to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than C or Pascal. Python uses whitespace indentation, rather than curly brackets or keywords, to delimit blocks. An increase in indentation comes after certain statements; a decrease in indentation signifies the end of the current block. Thus, the program's visual structure accurately represents its semantic structure. This feature is sometimes termed the off-side rule. Some other languages use indentation this way; but in most, indentation has no semantic meaning. The recommended indent size is four spaces. Python's statements include the following: The assignment statement (=) binds a name as a reference to a separate, dynamically allocated object. Variables may subsequently be rebound at any time to any object. In Python, a variable name is a generic reference holder without a fixed data type; however, it always refers to some object with a type. This is called dynamic typing—in contrast to statically-typed languages, where each variable may contain only a value of a certain type. Python does not support tail call optimization or first-class continuations; according to Van Rossum, the language never will. However, better support for coroutine-like functionality is provided by extending Python's generators. Before 2.5, generators were lazy iterators; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into a generator function; and from version 3.3, data can be passed through multiple stack levels. Python's expressions include the following: In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as Common Lisp, Scheme, or Ruby. This distinction leads to duplicating some functionality, for example: A statement cannot be part of an expression; because of this restriction, expressions such as list and dict comprehensions (and lambda expressions) cannot contain statements. As a particular case, an assignment statement such as a = 1 cannot be part of the conditional expression of a conditional statement. Python uses duck typing, and it has typed objects but untyped variable names. Type constraints are not checked at definition time; rather, operations on an object may fail at usage time, indicating that the object is not of an appropriate type. Despite being dynamically typed, Python is strongly typed, forbidding operations that are poorly defined (e.g., adding a number and a string) rather than quietly attempting to interpret them. Python allows programmers to define their own types using classes, most often for object-oriented programming. New instances of classes are constructed by calling the class, for example, SpamClass() or EggsClass()); the classes are instances of the metaclass type (which is an instance of itself), thereby allowing metaprogramming and reflection. Before version 3.0, Python had two kinds of classes, both using the same syntax: old-style and new-style. Current Python versions support the semantics of only the new style. Python supports optional type annotations. These annotations are not enforced by the language, but may be used by external tools such as mypy to catch errors. Python includes a module typing including several type names for type annotations. Also, mypy supports a Python compiler called mypyc, which leverages type annotations for optimization. 1.33333 frozenset() Python includes conventional symbols for arithmetic operators (+, -, *, /), the floor-division operator //, and the modulo operator %. (With the modulo operator, a remainder can be negative, e.g., 4 % -3 == -2.) Also, Python offers the ** symbol for exponentiation, e.g. 5**3 == 125 and 9**0.5 == 3.0. Also, it offers the matrix‑multiplication operator @ . These operators work as in traditional mathematics; with the same precedence rules, the infix operators + and - can also be unary, to represent positive and negative numbers respectively. Division between integers produces floating-point results. The behavior of division has changed significantly over time: In Python terms, the / operator represents true division (or simply division), while the // operator represents floor division. Before version 3.0, the / operator represents classic division. Rounding towards negative infinity, though a different method than in most languages, adds consistency to Python. For instance, this rounding implies that the equation (a + b)//b == a//b + 1 is always true. Also, the rounding implies that the equation b*(a//b) + a%b == a is valid for both positive and negative values of a. As expected, the result of a%b lies in the half-open interval [0, b), where b is a positive integer; however, maintaining the validity of the equation requires that the result must lie in the interval (b, 0] when b is negative. Python provides a round function for rounding a float to the nearest integer. For tie-breaking, Python 3 uses the round to even method: round(1.5) and round(2.5) both produce 2. Python versions before 3 used the round-away-from-zero method: round(0.5) is 1.0, and round(-0.5) is −1.0. Python allows Boolean expressions that contain multiple equality relations to be consistent with general usage in mathematics. For example, the expression a < b < c tests whether a is less than b and b is less than c. C-derived languages interpret this expression differently: in C, the expression would first evaluate a < b, resulting in 0 or 1, and that result would then be compared with c. Python uses arbitrary-precision arithmetic for all integer operations. The Decimal type/class in the decimal module provides decimal floating-point numbers to a pre-defined arbitrary precision with several rounding modes. The Fraction class in the fractions module provides arbitrary precision for rational numbers. Due to Python's extensive mathematics library and the third-party library NumPy, the language is frequently used for scientific scripting in tasks such as numerical data processing and manipulation. Functions are created in Python by using the def keyword. A function is defined similarly to how it is called, by first providing the function name and then the required parameters. Here is an example of a function that prints its inputs: To assign a default value to a function parameter in case no actual value is provided at run time, variable-definition syntax can be used inside the function header. Code examples "Hello, World!" program: Program to calculate the factorial of a non-negative integer: Libraries Python's large standard library is commonly cited as one of its greatest strengths. For Internet-facing applications, many standard formats and protocols such as MIME and HTTP are supported. The language includes modules for creating graphical user interfaces, connecting to relational databases, generating pseudorandom numbers, arithmetic with arbitrary-precision decimals, manipulating regular expressions, and unit testing. Some parts of the standard library are covered by specifications—for example, the Web Server Gateway Interface (WSGI) implementation wsgiref follows PEP 333—but most parts are specified by their code, internal documentation, and test suites. However, because most of the standard library is cross-platform Python code, only a few modules must be altered or rewritten for variant implementations. As of 13 March 2025,[update] the Python Package Index (PyPI), the official repository for third-party Python software, contains over 614,339 packages. Development environments Most[which?] Python implementations (including CPython) include a read–eval–print loop (REPL); this permits the environment to function as a command line interpreter, with which users enter statements sequentially and receive results immediately. Also, CPython is bundled with an integrated development environment (IDE) called IDLE, which is oriented toward beginners.[citation needed] Other shells, including IDLE and IPython, add additional capabilities such as improved auto-completion, session-state retention, and syntax highlighting. Standard desktop IDEs include PyCharm, Spyder, and Visual Studio Code; there are web browser-based IDEs, such as the following environments: Implementations CPython is the reference implementation of Python. This implementation is written in C, meeting the C11 standard since version 3.11. Older versions use the C89 standard with several select C99 features, but third-party extensions are not limited to older C versions—e.g., they can be implemented using C11 or C++. CPython compiles Python programs into an intermediate bytecode, which is then executed by a virtual machine. CPython is distributed with a large standard library written in a combination of C and native Python. CPython is available for many platforms, including Windows and most modern Unix-like systems, including macOS (and Apple M1 Macs, since Python 3.9.1, using an experimental installer). Starting with Python 3.9, the Python installer intentionally fails to install on Windows 7 and 8; Windows XP was supported until Python 3.5, with unofficial support for VMS. Platform portability was one of Python's earliest priorities. During development of Python 1 and 2, even OS/2 and Solaris were supported; since that time, support has been dropped for many platforms. All current Python versions (since 3.7) support only operating systems that feature multithreading, by now supporting not nearly as many operating systems (dropping many outdated) than in the past. All alternative implementations have at least slightly different semantics. For example, an alternative may include unordered dictionaries, in contrast to other current Python versions. As another example in the larger Python ecosystem, PyPy does not support the full C Python API. Creating an executable with Python often is done by bundling an entire Python interpreter into the executable, which causes binary sizes to be massive for small programs, yet there exist implementations that are capable of truly compiling Python. Alternative implementations include the following: Stackless Python is a significant fork of CPython that implements microthreads. This implementation uses the call stack differently, thus allowing massively concurrent programs. PyPy also offers a stackless version. Just-in-time Python compilers have been developed, but are now unsupported: There are several compilers/transpilers to high-level object languages; the source language is unrestricted Python, a subset of Python, or a language similar to Python: There are also specialized compilers: Some older projects existed, as well as compilers not designed for use with Python 3.x and related syntax: A performance comparison among various Python implementations, using a non-numerical (combinatorial) workload, was presented at EuroSciPy '13. In addition, Python's performance relative to other programming languages is benchmarked by The Computer Language Benchmarks Game. There are several approaches to optimizing Python performance, despite the inherent slowness of an interpreted language. These approaches include the following strategies or tools: Language Development Python's development is conducted mostly through the Python Enhancement Proposal (PEP) process; this process is the primary mechanism for proposing major new features, collecting community input on issues, and documenting Python design decisions. Python coding style is covered in PEP 8. Outstanding PEPs are reviewed and commented on by the Python community and the steering council. Enhancement of the language corresponds with development of the CPython reference implementation. The mailing list python-dev is the primary forum for the language's development. Specific issues were originally discussed in the Roundup bug tracker hosted by the foundation. In 2022, all issues and discussions were migrated to GitHub. Development originally took place on a self-hosted source-code repository running Mercurial, until Python moved to GitHub in January 2017. CPython's public releases have three types, distinguished by which part of the version number is incremented: Many alpha, beta, and release-candidates are also released as previews and for testing before final releases. Although there is a rough schedule for releases, they are often delayed if the code is not ready yet. Python's development team monitors the state of the code by running a large unit test suite during development. The major academic conference on Python is PyCon. Also, there are special Python mentoring programs, such as PyLadies. Naming Python's name is inspired by the British comedy group Monty Python, whom Python creator Guido van Rossum enjoyed while developing the language. Monty Python references appear frequently in Python code and culture; for example, the metasyntactic variables often used in Python literature are spam and eggs, rather than the traditional foo and bar. Also, the official Python documentation contains various references to Monty Python routines. Python users are sometimes referred to as "Pythonistas". Languages influenced by Python See also Notes References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Andromeda_(constellation)] | [TOKENS: 3551] |
Contents Andromeda (constellation) Andromeda is one of the 48 constellations listed by the 2nd-century Greco-Roman astronomer Ptolemy, and one of the 88 modern constellations. Located in the northern celestial hemisphere, it is named for Andromeda, daughter of Cassiopeia, in the Greek myth, who was chained to a rock to be eaten by the sea monster Cetus. Andromeda is most prominent during autumn evenings in the Northern Hemisphere, along with several other constellations named for characters in the Perseus myth. Because of its northern declination, Andromeda is visible only north of 40° south latitude; for observers farther south, it always lies below the horizon. It is one of the largest constellations, with an area of 722 square degrees. This is over 1,400 times the size of the full moon, 55% of the size of the largest constellation, Hydra, and over 10 times the size of the smallest constellation, Crux. Its brightest star, Alpheratz (Alpha Andromedae), is a binary star that has also been counted as a part of Pegasus, while Gamma Andromedae (Almach) is a colorful binary and a popular target for amateur astronomers. With a variable brightness similar to Alpheratz, Mirach (Beta Andromedae) is a red giant, its color visible to the naked eye. The constellation's most obvious deep-sky object is the naked-eye Andromeda Galaxy (M31, also called the Great Galaxy of Andromeda), the closest spiral galaxy to the Milky Way and one of the brightest Messier objects. Several fainter galaxies, including M31's companions M110 and M32, as well as the more distant NGC 891, lie within Andromeda. The Blue Snowball Nebula, a planetary nebula, is visible in a telescope as a blue circular object. In Chinese astronomy, the stars that make up Andromeda were members of four different constellations that had astrological and mythological significance; a constellation related to Andromeda also exists in Hindu mythology. Andromeda is the location of the radiant for the Andromedids, a weak meteor shower that occurs in November. History and mythology The uranography of Andromeda has its roots most firmly in the Greek tradition, though a female figure in Andromeda's location had appeared earlier in Babylonian astronomy. The stars that make up Pisces and the middle portion of modern Andromeda formed a constellation representing a fertility goddess, sometimes named as Anunitum or the Lady of the Heavens. Andromeda is known as "the Chained Lady" or "the Chained Woman" in English. It was known as Mulier Catenata ("chained woman") in Latin and al-Mar'at al Musalsalah in Arabic. It has also been called Persea ("Perseus's wife") or Cepheis ("Cepheus's daughter"), all names that refer to Andromeda's role in the Greco-Roman myth of Perseus, in which Cassiopeia, the queen of Aethiopia, bragged that her daughter was more beautiful than the Nereids, sea nymphs blessed with incredible beauty. Offended at her remark, the nymphs petitioned Poseidon to punish Cassiopeia for her insolence, which he did by commanding the sea monster Cetus to attack Aethiopia. Andromeda's panicked father, Cepheus, was told by the Oracle of Ammon that the only way to save his kingdom was to sacrifice his daughter to Cetus. She was chained to a rock by the sea but was saved by the hero Perseus, who in one version of the story used the head of Medusa to turn the monster into stone; in another version, by the Roman poet Ovid in his Metamorphoses, Perseus slew the monster with his diamond sword. Perseus and Andromeda then married; the myth recounts that the couple had nine children together – seven sons and two daughters – and founded Mycenae and its Persideae dynasty. After Andromeda's death Athena placed her in the sky as a constellation, to honor her. Three of the neighboring constellations (Perseus, Cassiopeia and Cepheus) represent characters in the Perseus myth, while Cetus retreats to beyond Pisces. It is connected with the constellation Pegasus. Andromeda was one of the original 48 constellations formulated by Ptolemy in his 2nd-century Almagest, in which it was defined as a specific pattern of stars. She is typically depicted with α Andromedae as her head, ο and λ Andromedae as her chains, and δ, π, μ, β, and γ her body and legs. However, there is no universal depiction of Andromeda and the stars used to represent her body, head, and chains. Arab astronomers were aware of Ptolemy's constellations, but they included a second constellation representing a fish overlapping Andromeda's body; the nose of this fish was marked by a hazy patch that we now know as the Andromeda Galaxy, M31. Several stars from Andromeda and most of the stars in Lacerta were combined in 1787 by German astronomer Johann Bode to form Honores Friderici (also called Friedrichs Ehre). It was designed to honour King Frederick II of Prussia, but quickly fell into disuse. Since the time of Ptolemy, Andromeda has remained a constellation and is officially recognized by the International Astronomical Union. Like all those that date back to a pattern known to Ptolemy, it is attributed to a wider zone and thus many surrounding stars. In 1922, the IAU defined its recommended three-letter abbreviation, "And". The official boundaries of Andromeda were defined in 1930 by Belgian astronomer Eugène Delporte as a polygon of 36 segments. Its right ascension is between 22h 57.5m and 2h 39.3m and its declination is between 53.19° and 21.68° in the equatorial coordinate system. In traditional Chinese astronomy, nine stars from Andromeda (including Beta Andromedae, Mu Andromedae, and Nu Andromedae), along with seven stars from Pisces, formed an elliptical constellation called Kui (奎宿, Legs). This constellation either represented the foot of a walking person or a wild boar. Gamma Andromedae and its neighbors were called Tian Dajiangjun (天大将军, Heaven's Great General), representing honour in astrology and a great general in mythology. Alpha Andromedae and Gamma Pegasi together made Bi (壁宿, Wall), representing the eastern wall of the imperial palace and/or the emperor's personal library. For the Chinese, the northern swath of Andromeda formed a stable for changing horses (tianjiu, 天厩, stable on sky) and the far western part, along with most of Lacerta, became Tengshe, a flying snake. An Arab constellation called "al-Hut" (the fish) was composed of several stars in Andromeda, M31, and several stars in Pisces. ν And, μ And, β And, η And, ζ And, ε And, δ And, π And, and 32 And were all included from Andromeda; ν Psc, φ Psc, χ Psc, and ψ1 Psc were included from Pisces. Hindu legends surrounding Andromeda are similar to the Greek myths. Ancient Sanskrit texts depict Antarmada chained to a rock, as in the Greek myth. Scholars believe that the Hindu and Greek astrological myths were closely linked; one piece of evidence cited is the similarity between the names "Antarmada" and "Andromeda". Andromeda is also associated with the Mesopotamian creation story of Tiamat, the goddess of Chaos. She bore many demons for her husband, Apsu, but eventually decided to destroy them in a war that ended when Marduk killed her. He used her body to create the constellations as markers of time for humans. In the Marshall Islands, Andromeda, Cassiopeia, Triangulum, and Aries are incorporated into a constellation representing a porpoise. Andromeda's bright stars are mostly in the body of the porpoise; Cassiopeia represents its tail and Aries its head. In the Tuamotu islands, Alpha Andromedae was called Takurua-e-te-tuki-hanga-ruki, meaning "Star of the wearisome toil", and Beta Andromedae was called Piringa-o-Tautu. Features Of the stars brighter than 4th magnitude (and those with measured luminosity), Andromeda has a relatively even distribution of evolved and main-sequence stars. Andromeda's borders contain many visible distant galaxies. The most famous deep-sky object in Andromeda is the spiral galaxy cataloged as Messier 31 (M31) or NGC 224 but known colloquially as the Andromeda Galaxy for the constellation. M31 is one of the most distant objects visible to the naked eye, 2.2 million light-years from Earth (estimates range up to 2.5 million light-years). It is seen under a dark, transparent sky as a hazy patch in the north of the constellation. M31 is the largest neighboring galaxy to the Milky Way and the largest member of the Local Group of galaxies. In absolute terms, M31 is approximately 200,000 light-years in diameter, twice the size of the Milky Way. It is an enormous – 192.4 by 62.2 arcminutes in apparent size – barred spiral galaxy similar in form to the Milky Way and at an approximate magnitude of 3.5, is one of the brightest deep-sky objects in the northern sky. Despite being visible to the naked eye, the "little cloud" near Andromeda's figure was not recorded until AD 964, when the Arab astronomer al-Sufi wrote his Book of Fixed Stars. M31 was first observed telescopically shortly after its invention, by Simon Marius in 1612. The future of the Andromeda and Milky Way galaxies may be interlinked: in about five billion years, the two could potentially begin an Andromeda–Milky Way collision that would spark extensive new star formation. American astronomer Edwin Hubble included M31 (then known as the Andromeda Nebula) in his groundbreaking 1923 research on galaxies. Using the 100-inch Hooker Telescope at Mount Wilson Observatory in California, he observed Cepheid variable stars in M31 during a search for novae, allowing him to determine their distance by using the stars as standard candles. The distance he found was far greater than the size of the Milky Way, which led him to the conclusion that many similar objects were "island universes" on their own. Hubble originally estimated that the Andromeda Galaxy was 900,000 light-years away, but Ernst Öpik's estimate in 1925 put the distance closer to 1.5 million light-years. The Andromeda Galaxy's two main companions, M32 and M110 (also known as NGC 221 and NGC 205, respectively) are faint elliptical galaxies that lie near it. M32, visible with a far smaller size of 8.7 by 6.4 arcminutes, compared to M110, appears superimposed on the larger galaxy in a telescopic view as a hazy smudge, M110 also appears slightly larger and distinct from the larger galaxy; M32 is 0.5° south of the core, M110 is 1° northwest of the core. M32 was discovered in 1749 by French astronomer Guillaume Le Gentil and has since been found to lie closer to Earth than the Andromeda Galaxy itself. It is viewable in binoculars from a dark site owing to its high surface brightness of 10.1 and overall magnitude of 9.0. M110 is classified as either a dwarf spheroidal galaxy or simply a generic elliptical galaxy. It is far fainter than M31 and M32, but larger than M32 with a surface brightness of 13.2, magnitude of 8.9, and size of 21.9 by 10.9 arcminutes. The Andromeda Galaxy has a total of 15 satellite galaxies, including M32 and M110. Nine of these lie in a plane, which has caused astronomers to infer that they have a common origin. These satellite galaxies, like the satellites of the Milky Way, tend to be older, gas-poor dwarf elliptical and dwarf spheroidal galaxies. Along with the Andromeda Galaxy and its companions, the constellation also features NGC 891 (Caldwell 23), a smaller galaxy just east of Almach. It is a barred spiral galaxy seen edge-on, with a dark dust lane visible down the middle. NGC 891 is incredibly faint and small despite its magnitude of 9.9, as its surface brightness of 14.6 indicates; it is 13.5 by 2.8 arcminutes in size. NGC 891 was discovered by the brother-and-sister team of William and Caroline Herschel in August 1783. This galaxy is at an approximate distance of 30 million light-years from Earth, calculated from its redshift of 0.002. Andromeda's most celebrated open cluster is NGC 752 (Caldwell 28) at an overall magnitude of 5.7. It is a loosely scattered cluster in the Milky Way that measures 49 arcminutes across and features approximately twelve bright stars, although more than 60 stars of approximately 9th magnitude become visible at low magnifications in a telescope. It is considered to be one of the more inconspicuous open clusters. The other open cluster in Andromeda is NGC 7686, which has a similar magnitude of 5.6 and is also a part of the Milky Way. It contains approximately 20 stars in a diameter of 15 arcminutes, making it a tighter cluster than NGC 752. There is one prominent planetary nebula in Andromeda: NGC 7662 (Caldwell 22). Lying approximately 3 degrees southwest of Iota Andromedae at a distance of about 4,000 light-years from Earth, the "Blue Snowball Nebula" is a popular target for amateur astronomers. It earned its popular name because it appears as a faint, round, blue-green object in a telescope, with an overall magnitude of 9.2. Upon further magnification, it is visible as a slightly elliptical annular disk that gets darker towards the center, with a magnitude 13.2 central star. The nebula has an overall magnitude of 9.2 and is 20 by 130 arcseconds in size. Each November, the Andromedids meteor shower appears to radiate from Andromeda. The shower peaks in mid-to-late November every year, but has a low peak rate of fewer than 2 meteors per hour. Astronomers have often associated the Andromedids with Biela's Comet, which was destroyed in the 19th century, but that connection is disputed. Andromedid meteors are known for being very slow and the shower itself is considered to be diffuse, as meteors can be seen coming from nearby constellations as well as from Andromeda itself. Andromedid meteors sometimes appear as red fireballs. The Andromedids were associated with the most spectacular meteor showers of the 19th century; the storms of 1872 and 1885 were estimated to have a peak rate of 2 meteors per second (a zenithal hourly rate of 10,000), prompting a Chinese astronomer to compare the meteors to falling rain. The Andromedids had another outburst on December 3–5, 2011, the most active shower since 1885, with a maximum zenithal hourly rate of 50 meteors per hour. The 2011 outburst was linked to ejecta from Comet Biela, which passed close to the Sun in 1649. None of the meteoroids observed were associated with material from the comet's 1846 disintegration. The observers of the 2011 outburst predicted outbursts in 2018, 2023, and 2036. See also References Citations Bibliography Online sources SIMBAD External links Media related to Andromeda (category) at Wikimedia Commons |
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[SOURCE: https://en.wikipedia.org/wiki/Robert_H._Dicke] | [TOKENS: 1653] |
Contents Robert H. Dicke Robert Henry Dicke (/ˈdɪki/; May 6, 1916 – March 4, 1997) was an American astronomer and physicist who made important contributions to the fields of astrophysics, atomic physics, cosmology and gravity. He was the Albert Einstein Professor in Science at Princeton University (1975–1984). Biography Born in St. Louis, Missouri, Dicke completed his bachelor's degree at Princeton University and his doctorate, in 1939, from the University of Rochester in nuclear physics. During the Second World War he worked in the Radiation Laboratory at the Massachusetts Institute of Technology where he worked on the development of radar and designed the Dicke radiometer, a microwave receiver. He used this to set a limit on the temperature of the microwave background radiation, from the roof of the Radiation Laboratory, of less than 20 kelvins. In 1946, he returned to Princeton University, where he remained for the remainder of his career. He did some work in atomic physics, particularly on the laser and measuring the gyromagnetic ratio of the electron. An important contribution to the field of spectroscopy and radiative transfer was his prediction of the phenomenon called Dicke narrowing: When the mean free path of an atom is much smaller than the wavelength of one of its radiation transitions, the atom changes velocity and direction many times during the emission or absorption of a photon. This causes an averaging over different Doppler states and results in an atomic linewidth that is much narrower than the Doppler width. Dicke narrowing occurs at relatively low pressures in the millimeter wave and microwave regions (where it is used in atomic clocks to improve precision). Dicke narrowing is analogous to the Mössbauer effect for gamma rays. In 1956, approximately two years before Charles Hard Townes and Arthur Leonard Schawlow filed their patent application, Dicke filed a patent titled "Molecular Amplification Generation Systems and Methods" with claims of how to build an infrared laser and the use of an open resonator and the patent was awarded on September 9, 1958. He spent the remainder of his career developing a program of precision tests of general relativity using the framework of the equivalence principle. In 1957, he first proposed an alternative theory of gravitation inspired by Mach's principle and Paul Dirac's large numbers hypothesis. In 1961, this led to the Brans–Dicke theory of gravitation, developed with Carl H. Brans, an equivalence-principle violating modification of general relativity. A highlight experiment was the test of the equivalence principle by Roll, Krotkov and Dicke, which was a factor of 100 more accurate than previous work. He also made measurements of solar oblateness which were useful in understanding the perihelion precession of Mercury's orbit, one of the classical tests of general relativity. Dirac had hypothesized that because the gravitational constant G is very roughly equal to the inverse age of the universe in certain units, then G must vary to maintain this equality. Dicke realized that Dirac's relation could be a selection effect: fundamental physical laws connect G to the lifetime of what are called main sequence stars, such as the Sun, and these stars, according to Dicke, are necessary for the existence of life. At any other epoch, when the equality did not hold, there would be no intelligent life around to notice the discrepancy. This was the first modern application of what is now called the weak anthropic principle. In the early 1960s, work on Brans–Dicke theory led Dicke to think about the early Universe, and with Jim Peebles he re-derived the prediction of a cosmic microwave background (having allegedly forgotten the earlier prediction of George Gamow and co-workers). Dicke, with David Todd Wilkinson and Peter G. Roll, immediately began building a Dicke radiometer to search for the radiation. They were preceded by the accidental detection made by Arno Penzias and Robert Woodrow Wilson (also using a Dicke radiometer), who were working at Bell Labs near Princeton. Nevertheless, Dicke's group made the second clean detection, and their theoretical interpretation of Penzias and Wilson's results showed that theories of the early universe had moved from pure speculation into well-tested physics. In 1970, Dicke argued that the universe must have very nearly the critical density of matter needed to stop it expanding forever. Standard models of the universe pass through stages dominated by radiation, matter, curvature etc. Transitions between stages are very special cosmic times which a priori could differ by many orders of magnitude. Since there is a non-negligible amount of matter, either we are coincidentally living close to the transition to or from the matter-dominated stage, or we are in the middle of it; the latter is preferred since the coincidences are highly unlikely (an application of the Copernican principle). This implies a negligible curvature, so the universe must have almost critical density. This has been called the "Dicke coincidence" argument. In fact it gives the wrong answer, since we seem to be living at the time of transition between the matter and dark energy stages. An anthropic explanation of the failure of Dicke's argument was given by Weinberg. Dicke was also responsible for developing the lock-in amplifier, which is an indispensable tool in the area of applied science and engineering. Many of Dicke's experiments capitalize on lock-in in some way or another.[citation needed] However, in an interview with Martin Harwit he claims that even though he is often credited with the invention of the device; he believes he read about it in a review of scientific equipment written by Walter C. Michels, a professor at Bryn Mawr. Dicke is also credited with the invention of a kind of radio receiver, called a "Dicke Radiometric Receiver" or simply "Dicke Radiometer", developed by Dicke during WWII. His radiometer was characterized by a noise temperature calibration technique using a switchable resistor, known as "Dicke Resistor". Dicke was awarded the 1970 National Medal of Science. In 1973, he was awarded the Comstock Prize in Physics from the National Academy of Sciences, of which he was a member. He was also a member of the American Academy of Arts and Sciences and the American Philosophical Society. Dicke was nominated for the Nobel Prize in Physics multiple times. Peebles ended his own 2019 Nobel Lecture with a statement of disappointment that Dicke had never been awarded the prize, then said, "But I am satisfied now because my Nobel Prize is closure of what Bob set in motion, his great goal of establishing an empirically based gravity physics, by the establishment of the empirically-based relativistic cosmology." Marriage and family life Dicke married Annie Currie in 1942. Currie, of Scottish descent, was born in Barrow-in-Furness in England in 1920 and as a young girl immigrated to Rochester, New York, via Australia and New Zealand, of which Annie had very fond memories. At the beginning of World War II, Dicke was asked to assist the war effort by applying his skills to the development of radar with the Massachusetts Institute of Technology. At the end of the war, Dicke and Currie moved to Princeton, New Jersey, where Robert was on the faculty at Princeton University. Dicke died there March 4, 1997. Currie continued to live in Princeton until 2002. For the last years of her life she lived in Hightstown, New Jersey at Meadow Lakes Retirement Community until her death in 2005. They had one daughter, Nancy born in 1945, and two sons, John born in 1946 and James born in 1953. At the time of Dicke's death they had six grandchildren and a great grandchild. Bibliography References Sources External links |
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[SOURCE: https://en.wikipedia.org/wiki/Python_(programming_language)#cite_ref-38] | [TOKENS: 4314] |
Contents Python (programming language) Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically type-checked and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language. Python 3.0, released in 2008, was a major revision and not completely backward-compatible with earlier versions. Beginning with Python 3.5, capabilities and keywords for typing were added to the language, allowing optional static typing. As of 2026[update], the Python Software Foundation supports Python 3.10, 3.11, 3.12, 3.13, and 3.14, following the project's annual release cycle and five-year support policy. Python 3.15 is currently in the alpha development phase, and the stable release is expected to come out in October 2026. Earlier versions in the 3.x series have reached end-of-life and no longer receive security updates. Python has gained widespread use in the machine learning community. It is widely taught as an introductory programming language. Since 2003, Python has consistently ranked in the top ten of the most popular programming languages in the TIOBE Programming Community Index, which ranks based on searches in 24 platforms. History Python was conceived in the late 1980s by Guido van Rossum at Centrum Wiskunde & Informatica (CWI) in the Netherlands. It was designed as a successor to the ABC programming language, which was inspired by SETL, capable of exception handling and interfacing with the Amoeba operating system. Python implementation began in December 1989. Van Rossum first released it in 1991 as Python 0.9.0. Van Rossum assumed sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from responsibilities as Python's "benevolent dictator for life" (BDFL); this title was bestowed on him by the Python community to reflect his long-term commitment as the project's chief decision-maker. (He has since come out of retirement and is self-titled "BDFL-emeritus".) In January 2019, active Python core developers elected a five-member Steering Council to lead the project. The name Python derives from the British comedy series Monty Python's Flying Circus. (See § Naming.) Python 2.0 was released on 16 October 2000, featuring many new features such as list comprehensions, cycle-detecting garbage collection, reference counting, and Unicode support. Python 2.7's end-of-life was initially set for 2015, and then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python 3. It no longer receives security patches or updates. While Python 2.7 and older versions are officially unsupported, a different unofficial Python implementation, PyPy, continues to support Python 2, i.e., "2.7.18+" (plus 3.11), with the plus signifying (at least some) "backported security updates". Python 3.0 was released on 3 December 2008, and was a major revision and not completely backward-compatible with earlier versions, with some new semantics and changed syntax. Python 2.7.18, released in 2020, was the last release of Python 2. Several releases in the Python 3.x series have added new syntax to the language, and made a few (considered very minor) backward-incompatible changes. As of January 2026[update], Python 3.14.3 is the latest stable release. All older 3.x versions had a security update down to Python 3.9.24 then again with 3.9.25, the final version in 3.9 series. Python 3.10 is, since November 2025, the oldest supported branch. Python 3.15 has an alpha released, and Android has an official downloadable executable available for Python 3.14. Releases receive two years of full support followed by three years of security support. Design philosophy and features Python is a multi-paradigm programming language. Object-oriented programming and structured programming are fully supported, and many of their features support functional programming and aspect-oriented programming – including metaprogramming and metaobjects. Many other paradigms are supported via extensions, including design by contract and logic programming. Python is often referred to as a 'glue language' because it is purposely designed to be able to integrate components written in other languages. Python uses dynamic typing and a combination of reference counting and a cycle-detecting garbage collector for memory management. It uses dynamic name resolution (late binding), which binds method and variable names during program execution. Python's design offers some support for functional programming in the "Lisp tradition". It has filter, map, and reduce functions; list comprehensions, dictionaries, sets, and generator expressions. The standard library has two modules (itertools and functools) that implement functional tools borrowed from Haskell and Standard ML. Python's core philosophy is summarized in the Zen of Python (PEP 20) written by Tim Peters, which includes aphorisms such as these: However, Python has received criticism for violating these principles and adding unnecessary language bloat. Responses to these criticisms note that the Zen of Python is a guideline rather than a rule. The addition of some new features had been controversial: Guido van Rossum resigned as Benevolent Dictator for Life after conflict about adding the assignment expression operator in Python 3.8. Nevertheless, rather than building all functionality into its core, Python was designed to be highly extensible via modules. This compact modularity has made it particularly popular as a means of adding programmable interfaces to existing applications. Van Rossum's vision of a small core language with a large standard library and easily extensible interpreter stemmed from his frustrations with ABC, which represented the opposite approach. Python claims to strive for a simpler, less-cluttered syntax and grammar, while giving developers a choice in their coding methodology. Python lacks do .. while loops, which Rossum considered harmful. In contrast to Perl's motto "there is more than one way to do it", Python advocates an approach where "there should be one – and preferably only one – obvious way to do it". In practice, however, Python provides many ways to achieve a given goal. There are at least three ways to format a string literal, with no certainty as to which one a programmer should use. Alex Martelli is a Fellow at the Python Software Foundation and Python book author; he wrote that "To describe something as 'clever' is not considered a compliment in the Python culture." Python's developers typically prioritize readability over performance. For example, they reject patches to non-critical parts of the CPython reference implementation that would offer increases in speed that do not justify the cost of clarity and readability.[failed verification] Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as C, or by using a just-in-time compiler like PyPy. Also, it is possible to transpile to other languages. However, this approach either fails to achieve the expected speed-up, since Python is a very dynamic language, or only a restricted subset of Python is compiled (with potential minor semantic changes). Python is meant to be a fun language to use. This goal is reflected in the name – a tribute to the British comedy group Monty Python – and in playful approaches to some tutorials and reference materials. For instance, some code examples use the terms "spam" and "eggs" (in reference to a Monty Python sketch), rather than the typical terms "foo" and "bar". A common neologism in the Python community is pythonic, which has a broad range of meanings related to program style: Pythonic code may use Python idioms well; be natural or show fluency in the language; or conform with Python's minimalist philosophy and emphasis on readability. Syntax and semantics Python is meant to be an easily readable language. Its formatting is visually uncluttered and often uses English keywords where other languages use punctuation. Unlike many other languages, it does not use curly brackets to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than C or Pascal. Python uses whitespace indentation, rather than curly brackets or keywords, to delimit blocks. An increase in indentation comes after certain statements; a decrease in indentation signifies the end of the current block. Thus, the program's visual structure accurately represents its semantic structure. This feature is sometimes termed the off-side rule. Some other languages use indentation this way; but in most, indentation has no semantic meaning. The recommended indent size is four spaces. Python's statements include the following: The assignment statement (=) binds a name as a reference to a separate, dynamically allocated object. Variables may subsequently be rebound at any time to any object. In Python, a variable name is a generic reference holder without a fixed data type; however, it always refers to some object with a type. This is called dynamic typing—in contrast to statically-typed languages, where each variable may contain only a value of a certain type. Python does not support tail call optimization or first-class continuations; according to Van Rossum, the language never will. However, better support for coroutine-like functionality is provided by extending Python's generators. Before 2.5, generators were lazy iterators; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into a generator function; and from version 3.3, data can be passed through multiple stack levels. Python's expressions include the following: In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as Common Lisp, Scheme, or Ruby. This distinction leads to duplicating some functionality, for example: A statement cannot be part of an expression; because of this restriction, expressions such as list and dict comprehensions (and lambda expressions) cannot contain statements. As a particular case, an assignment statement such as a = 1 cannot be part of the conditional expression of a conditional statement. Python uses duck typing, and it has typed objects but untyped variable names. Type constraints are not checked at definition time; rather, operations on an object may fail at usage time, indicating that the object is not of an appropriate type. Despite being dynamically typed, Python is strongly typed, forbidding operations that are poorly defined (e.g., adding a number and a string) rather than quietly attempting to interpret them. Python allows programmers to define their own types using classes, most often for object-oriented programming. New instances of classes are constructed by calling the class, for example, SpamClass() or EggsClass()); the classes are instances of the metaclass type (which is an instance of itself), thereby allowing metaprogramming and reflection. Before version 3.0, Python had two kinds of classes, both using the same syntax: old-style and new-style. Current Python versions support the semantics of only the new style. Python supports optional type annotations. These annotations are not enforced by the language, but may be used by external tools such as mypy to catch errors. Python includes a module typing including several type names for type annotations. Also, mypy supports a Python compiler called mypyc, which leverages type annotations for optimization. 1.33333 frozenset() Python includes conventional symbols for arithmetic operators (+, -, *, /), the floor-division operator //, and the modulo operator %. (With the modulo operator, a remainder can be negative, e.g., 4 % -3 == -2.) Also, Python offers the ** symbol for exponentiation, e.g. 5**3 == 125 and 9**0.5 == 3.0. Also, it offers the matrix‑multiplication operator @ . These operators work as in traditional mathematics; with the same precedence rules, the infix operators + and - can also be unary, to represent positive and negative numbers respectively. Division between integers produces floating-point results. The behavior of division has changed significantly over time: In Python terms, the / operator represents true division (or simply division), while the // operator represents floor division. Before version 3.0, the / operator represents classic division. Rounding towards negative infinity, though a different method than in most languages, adds consistency to Python. For instance, this rounding implies that the equation (a + b)//b == a//b + 1 is always true. Also, the rounding implies that the equation b*(a//b) + a%b == a is valid for both positive and negative values of a. As expected, the result of a%b lies in the half-open interval [0, b), where b is a positive integer; however, maintaining the validity of the equation requires that the result must lie in the interval (b, 0] when b is negative. Python provides a round function for rounding a float to the nearest integer. For tie-breaking, Python 3 uses the round to even method: round(1.5) and round(2.5) both produce 2. Python versions before 3 used the round-away-from-zero method: round(0.5) is 1.0, and round(-0.5) is −1.0. Python allows Boolean expressions that contain multiple equality relations to be consistent with general usage in mathematics. For example, the expression a < b < c tests whether a is less than b and b is less than c. C-derived languages interpret this expression differently: in C, the expression would first evaluate a < b, resulting in 0 or 1, and that result would then be compared with c. Python uses arbitrary-precision arithmetic for all integer operations. The Decimal type/class in the decimal module provides decimal floating-point numbers to a pre-defined arbitrary precision with several rounding modes. The Fraction class in the fractions module provides arbitrary precision for rational numbers. Due to Python's extensive mathematics library and the third-party library NumPy, the language is frequently used for scientific scripting in tasks such as numerical data processing and manipulation. Functions are created in Python by using the def keyword. A function is defined similarly to how it is called, by first providing the function name and then the required parameters. Here is an example of a function that prints its inputs: To assign a default value to a function parameter in case no actual value is provided at run time, variable-definition syntax can be used inside the function header. Code examples "Hello, World!" program: Program to calculate the factorial of a non-negative integer: Libraries Python's large standard library is commonly cited as one of its greatest strengths. For Internet-facing applications, many standard formats and protocols such as MIME and HTTP are supported. The language includes modules for creating graphical user interfaces, connecting to relational databases, generating pseudorandom numbers, arithmetic with arbitrary-precision decimals, manipulating regular expressions, and unit testing. Some parts of the standard library are covered by specifications—for example, the Web Server Gateway Interface (WSGI) implementation wsgiref follows PEP 333—but most parts are specified by their code, internal documentation, and test suites. However, because most of the standard library is cross-platform Python code, only a few modules must be altered or rewritten for variant implementations. As of 13 March 2025,[update] the Python Package Index (PyPI), the official repository for third-party Python software, contains over 614,339 packages. Development environments Most[which?] Python implementations (including CPython) include a read–eval–print loop (REPL); this permits the environment to function as a command line interpreter, with which users enter statements sequentially and receive results immediately. Also, CPython is bundled with an integrated development environment (IDE) called IDLE, which is oriented toward beginners.[citation needed] Other shells, including IDLE and IPython, add additional capabilities such as improved auto-completion, session-state retention, and syntax highlighting. Standard desktop IDEs include PyCharm, Spyder, and Visual Studio Code; there are web browser-based IDEs, such as the following environments: Implementations CPython is the reference implementation of Python. This implementation is written in C, meeting the C11 standard since version 3.11. Older versions use the C89 standard with several select C99 features, but third-party extensions are not limited to older C versions—e.g., they can be implemented using C11 or C++. CPython compiles Python programs into an intermediate bytecode, which is then executed by a virtual machine. CPython is distributed with a large standard library written in a combination of C and native Python. CPython is available for many platforms, including Windows and most modern Unix-like systems, including macOS (and Apple M1 Macs, since Python 3.9.1, using an experimental installer). Starting with Python 3.9, the Python installer intentionally fails to install on Windows 7 and 8; Windows XP was supported until Python 3.5, with unofficial support for VMS. Platform portability was one of Python's earliest priorities. During development of Python 1 and 2, even OS/2 and Solaris were supported; since that time, support has been dropped for many platforms. All current Python versions (since 3.7) support only operating systems that feature multithreading, by now supporting not nearly as many operating systems (dropping many outdated) than in the past. All alternative implementations have at least slightly different semantics. For example, an alternative may include unordered dictionaries, in contrast to other current Python versions. As another example in the larger Python ecosystem, PyPy does not support the full C Python API. Creating an executable with Python often is done by bundling an entire Python interpreter into the executable, which causes binary sizes to be massive for small programs, yet there exist implementations that are capable of truly compiling Python. Alternative implementations include the following: Stackless Python is a significant fork of CPython that implements microthreads. This implementation uses the call stack differently, thus allowing massively concurrent programs. PyPy also offers a stackless version. Just-in-time Python compilers have been developed, but are now unsupported: There are several compilers/transpilers to high-level object languages; the source language is unrestricted Python, a subset of Python, or a language similar to Python: There are also specialized compilers: Some older projects existed, as well as compilers not designed for use with Python 3.x and related syntax: A performance comparison among various Python implementations, using a non-numerical (combinatorial) workload, was presented at EuroSciPy '13. In addition, Python's performance relative to other programming languages is benchmarked by The Computer Language Benchmarks Game. There are several approaches to optimizing Python performance, despite the inherent slowness of an interpreted language. These approaches include the following strategies or tools: Language Development Python's development is conducted mostly through the Python Enhancement Proposal (PEP) process; this process is the primary mechanism for proposing major new features, collecting community input on issues, and documenting Python design decisions. Python coding style is covered in PEP 8. Outstanding PEPs are reviewed and commented on by the Python community and the steering council. Enhancement of the language corresponds with development of the CPython reference implementation. The mailing list python-dev is the primary forum for the language's development. Specific issues were originally discussed in the Roundup bug tracker hosted by the foundation. In 2022, all issues and discussions were migrated to GitHub. Development originally took place on a self-hosted source-code repository running Mercurial, until Python moved to GitHub in January 2017. CPython's public releases have three types, distinguished by which part of the version number is incremented: Many alpha, beta, and release-candidates are also released as previews and for testing before final releases. Although there is a rough schedule for releases, they are often delayed if the code is not ready yet. Python's development team monitors the state of the code by running a large unit test suite during development. The major academic conference on Python is PyCon. Also, there are special Python mentoring programs, such as PyLadies. Naming Python's name is inspired by the British comedy group Monty Python, whom Python creator Guido van Rossum enjoyed while developing the language. Monty Python references appear frequently in Python code and culture; for example, the metasyntactic variables often used in Python literature are spam and eggs, rather than the traditional foo and bar. Also, the official Python documentation contains various references to Monty Python routines. Python users are sometimes referred to as "Pythonistas". Languages influenced by Python See also Notes References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Reversi] | [TOKENS: 2942] |
Contents Reversi Reversi is a strategy board game for two players, played on an 8×8 uncheckered board. It was invented in 1883. Othello, a variant with a fixed initial setup of the board, was patented in 1971. Basics Two players compete, using 64 identical game pieces ("disks") that are light on one side and dark on the other. Each player chooses one color to use throughout the game. Players take turns placing one disk on an empty square, with their assigned color facing up. After a play is made, any disks of the opponent's color that lie in a straight line bounded by the one just played and another one in the current player's color are turned over. When all playable empty squares are filled, the player with more disks showing in their own color wins the game. History Englishmen Lewis Waterman and John W. Mollett[citation needed] both claim to have invented the game of reversi in 1883, each denouncing the other as a fraud. The game gained considerable popularity in England at the end of the 19th century. The game's first reliable mention is in the 21 August 1886 edition of The Saturday Review. Later mention includes an 1895 article in The New York Times, which describes reversi as "something like Go Bang, [...] played with 64 pieces." In 1893, the German games publisher Ravensburger started producing the game as one of its first titles. Two 18th century continental European books dealing with a game that may or may not be reversi are mentioned on page fourteen of the Spring 1989 Othello Quarterly, and there has been speculation, so far without documentation, that the game has older origins.[citation needed] A Japanese publication in 1907 titled World Games Rules Complete Collection (世界遊戯法大全) describes the board game reversi with the same rules as Othello where the first four pieces go in the center in a diagonal pattern and the player who cannot make a move simply passes. The modern version of the game—the most regularly used rule-set, and the one used in international tournaments—is marketed and recognized as Othello (オセロ, osero). It was patented in Japan in 1971 by Goro Hasegawa (legal name: Satoshi Hasegawa), then a 38-year-old salesman. Hasegawa initially explained that Othello was an improvement on reversi, but from around 2000, he began to claim that he invented it in Mito regardless of reversi. Hasegawa also claimed that the origin of reversi/Othello dates back 5,000 years. Hasegawa established the Japan Othello Association in March 1973, and held the first national Othello championship on 4 April 1973 in Japan. The Japanese game company Tsukuda Original launched Othello in late April 1973 in Japan under Hasegawa's license, which led to an immediate commercial success. The name was selected by Hasegawa as a reference to the Shakespearean play Othello, the Moor of Venice, referring to the conflict between the Moor Othello and Iago, and to the unfolding drama between Othello, who is black, and Desdemona, who is white. The green color of the board is inspired by the image of the general Othello, valiantly leading his battle in a green field. It can also be likened to a jealousy competition (jealousy being the central theme in Shakespeare's play, which popularized the term "green-eyed monster"), since players engulf the pieces of the opponent, thereby turning them to their possession. Othello was first launched in the U.S. in 1975 by Gabriel Industries and it also enjoyed commercial success there. Sales have reportedly exceeded $600 million. More than 40 million classic games have been sold in over 100 countries. Hasegawa's How to play Othello (Osero No Uchikata) in Japan in 1974, was published in 1977 in an English translation entitled How to Win at Othello. Kabushiki Kaisha Othello, which was owned by Hasegawa, registered the trademark "OTHELLO" for board games in Japan; Tsukuda Original registered the trademark in the rest of the world. All intellectual property regarding Othello outside Japan is now owned by MegaHouse, the Japanese toy company that acquired Tsukuda Original's successor PalBox. Rules Each of the disks' two sides corresponds to one player; they are referred to here as light and dark after the sides of Othello pieces, but any counters with distinctive faces are suitable. The game may for example be played with a chessboard and Scrabble pieces, with one player letters and the other backs. The historical version of reversi starts with an empty board, and the first two moves made by each player are in the four central squares of the board. The players place their disks alternately with their colors facing up and no captures are made. A player may choose to not play both pieces on the same diagonal, different from the standard Othello opening. It is also possible to play variants of Reversi and Othello where the second player's second move may or must flip one of the opposite-colored disks (as variants closest to the normal games). For the specific game of Othello, the game begins with four disks placed in a square in the middle of the grid, two facing light-side-up, two dark-side-up, so that the same-colored disks are on a diagonal. Convention has this such that the dark-side-up disks are to the north-east and south-west (from both players' perspectives), though this is only marginally consequential: where sequential openings' memorization is preferred, such players benefit from this. The dark player moves first. Dark must place a piece (dark-side-up) on the board and so that there exists at least one straight (horizontal, vertical, or diagonal) occupied line between the new piece and another dark piece, with one or more contiguous light pieces between them. For move one, dark has four options shown by translucently drawn pieces below: Play always alternates unless one player has no legal move, in which case they pass. After placing a dark disk, dark turns over (flips to dark, captures) the single disk (or chain of light disks) on the line between the new piece and an anchoring dark piece. Multiple chains of disks may be captured in a single move. No player can look back to the previous status of disks when playing moves. A valid move is one where at least one piece is reversed (flipped over). If dark decided to put a piece in the topmost location (all choices are strategically equivalent at this time), one piece gets turned over, so that the board appears thus: Now light plays. This player operates under the same rules, with the roles reversed: light lays down a light piece, causing a dark piece to flip. Possibilities at this time appear thus (indicated by transparent pieces): Light takes the bottom left option and reverses one piece: Players take alternate turns. If one player cannot make a valid move, play passes back to the other player. The game ends when the grid has filled up or if neither player can make a valid move. Examples where the game ends before the grid is completely filled: The player with the most pieces on the board at the end of the game wins. The game is scored by counting the number of discs in each player's color. If the game ended before the grid was completely filled, any empty squares are scored for the winner. However, if one player defaults by running out of time, that player's opponent wins regardless of the board configuration. There are varying methods to determine the official score when a player defaults. In common practice over the Internet, opponents agree upon a time-control of, typically, from one to thirty minutes per game per player. Standard time control in the World Championship is thirty minutes, and this or something close to it is common in over-the-board (as opposed to internet) tournament play generally. In time-defaulted games, where disk differential is used for tie-breaks in tournaments or for rating purposes, one common over-the-board procedure for the winner of defaulted contests to complete both sides' moves with the greater of the result thereby or one disk difference in the winner's favor being the recorded score. Games in which both players have the same number of disks their color at the end (almost always with a full-board 32–32 score) are not very common, but also not rare, and these are designated as 'ties' and scored as half of a win for each player in tournaments. The term 'draw' for such may also be heard, but is somewhat frowned upon. What are generally referred to as transcript sheets are generally in use in tournament over-the-board play, with both players obligated to record their game's moves by placing the number of each move in an 8×8 grid. This both enables players to look up past games of note and tournament directors and players to resolve disputes (according to whatever specific rules are in place) where claims that an illegal move, flip or other anomaly are voiced. An alternative recording method not requiring a grid is also in use, where positions on a board are labeled left to right by letters a through h and top to bottom by digits 1 through 8. Note that the numbers run in the opposite direction to the chess standard, and that the perspective may be that of either player (with no fixed standard). This alternate notational scheme is used primarily in verbal discussions or where a linear representation is desirable in print, but may also be permissible as during-game transcription by either or both players. Tournament over-the-board play has various ways of handling illegal moves and incorrect flips. For example, one procedure that has been used is to permit either player to make corrections going back some fixed number of moves. Anti-Reversi or Reversed Reversi is a variant of the game where the player wins who has fewer own-colored disks at the end of the game; draw is also a possible result. To put a disk on the board, the same rules apply as in normal reversi. Invented by the British mathematician and three times runner-up at the World Championship and five times British Champion Graham Brightwell, this is the tie-breaker that is now used in many tournaments including the W.O.C. If two players have the same number of points in the thirteen-round W.O.C. Swiss, the tie is resolved in favour of the player with the higher Brightwell Quotient.[citation needed] The Brightwell Quotient (BQ) is calculated as follows: Computer opponents and research Good Othello computer programs play very strongly against human opponents. This is mostly due to difficulties in human look-ahead peculiar to Othello: The interchangeability of the disks and therefore apparent strategic meaninglessness (as opposed to chess pieces for example) makes an evaluation of different moves much harder. This can be demonstrated with blindfold games, as the memorization of the board demands much more dedication from the players than in blindfold chess. The first tournament pitting Othello computer programs against human opponents took place in 1980. In it, then world champion Hiroshi Inoue, although he would go on to win the tournament, lost a game against the computer program The Moor. In 1997, the computer Othello program Logistello defeated the reigning human champion, Takeshi Murakami, six games to zero. Analysts have estimated the number of legal positions in Othello is at most 1028, and it has a game-tree complexity of approximately 1058. Mathematically, Othello is solved up to 8x8 board. On 4×4 and 6×6 boards under perfect play, the second player wins. On 8x8 board, the game results in draw under perfect play, according to an arXiv paper. The first of these proofs is relatively trivial, the second dates to around 1990, and the last one was done in 2023. When generalizing the game to play on an n×n board, the problem of determining if the first player has a winning move in a given position is PSPACE-complete. World Othello Championship The World Othello Championship (WOC), which started in 1977, was first organized by the Japan Othello Association. From 1978 until 2004, the World Othello Championship was organized by the Othello TD group and Anjar Co. In 2005, the World Othello Federation took over the responsibility for the WOC. From 1977 to 1986, each country could send one player to participate in the WOC. From 1987, each country could send up to three players to participate. In 1987, the title WOC team championship started. In 2005, a female championship category was added to the WOC. From 2006, each World Othello Federation member could send a full team of up to four players. In 2016, a youth champion title was added to the WOC. The WOC was cancelled in 2020 and 2021 due to the COVID-19 pandemic. Reception Games magazine included Othello in their "Top 100 Games of 1980", noting that it was "Based on the Victorian game of reversi" and had achieved "remarkable success in this country for an abstract game of strategy". Games magazine included Othello, Tournament Set in their "Top 100 Games of 1981", noting that by that time "Othello has become so popular that Gabriel now markets a computer version and a players' association publishes a quarterly magazine". Games magazine included Othello in their "Top 100 Games of 1982", noting that "Although the goal is to finish with the most pieces of your color up, the best strategy, paradoxically, is usually to limit your opponent's options by flipping over as few of his discs as possible during the first two-thirds of the game." Reviews See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Social_network#cite_ref-Kadu12_35-0] | [TOKENS: 5247] |
Contents Social network 1800s: Martineau · Tocqueville · Marx · Spencer · Le Bon · Ward · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Mannheim · Elias A social network is a social structure consisting of a set of social actors (such as individuals or organizations), networks of dyadic ties, and other social interactions between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities along with a variety of theories explaining the patterns observed in these structures. The study of these structures uses social network analysis to identify local and global patterns, locate influential entities, and examine dynamics of networks. For instance, social network analysis has been used in studying the spread of misinformation on social media platforms or analyzing the influence of key figures in social networks. Social networks and the analysis of them is an inherently interdisciplinary academic field which emerged from social psychology, sociology, statistics, and graph theory. Georg Simmel authored early structural theories in sociology emphasizing the dynamics of triads and "web of group affiliations". Jacob Moreno is credited with developing the first sociograms in the 1930s to study interpersonal relationships. These approaches were mathematically formalized in the 1950s and theories and methods of social networks became pervasive in the social and behavioral sciences by the 1980s. Social network analysis is now one of the major paradigms in contemporary sociology, and is also employed in a number of other social and formal sciences. Together with other complex networks, it forms part of the nascent field of network science. Overview The social network is a theoretical construct useful in the social sciences to study relationships between individuals, groups, organizations, or even entire societies (social units, see differentiation). The term is used to describe a social structure determined by such interactions. The ties through which any given social unit connects represent the convergence of the various social contacts of that unit. This theoretical approach is, necessarily, relational. An axiom of the social network approach to understanding social interaction is that social phenomena should be primarily conceived and investigated through the properties of relations between and within units, instead of the properties of these units themselves. Thus, one common criticism of social network theory is that individual agency is often ignored although this may not be the case in practice (see agent-based modeling). Precisely because many different types of relations, singular or in combination, form these network configurations, network analytics are useful to a broad range of research enterprises. In social science, these fields of study include, but are not limited to anthropology, biology, communication studies, economics, geography, information science, organizational studies, social psychology, sociology, and sociolinguistics. History In the late 1890s, both Émile Durkheim and Ferdinand Tönnies foreshadowed the idea of social networks in their theories and research of social groups. Tönnies argued that social groups can exist as personal and direct social ties that either link individuals who share values and belief (Gemeinschaft, German, commonly translated as "community") or impersonal, formal, and instrumental social links (Gesellschaft, German, commonly translated as "society"). Durkheim gave a non-individualistic explanation of social facts, arguing that social phenomena arise when interacting individuals constitute a reality that can no longer be accounted for in terms of the properties of individual actors. Georg Simmel, writing at the turn of the twentieth century, pointed to the nature of networks and the effect of network size on interaction and examined the likelihood of interaction in loosely knit networks rather than groups. Major developments in the field can be seen in the 1930s by several groups in psychology, anthropology, and mathematics working independently. In psychology, in the 1930s, Jacob L. Moreno began systematic recording and analysis of social interaction in small groups, especially classrooms and work groups (see sociometry). In anthropology, the foundation for social network theory is the theoretical and ethnographic work of Bronislaw Malinowski, Alfred Radcliffe-Brown, and Claude Lévi-Strauss. A group of social anthropologists associated with Max Gluckman and the Manchester School, including John A. Barnes, J. Clyde Mitchell and Elizabeth Bott Spillius, often are credited with performing some of the first fieldwork from which network analyses were performed, investigating community networks in southern Africa, India and the United Kingdom. Concomitantly, British anthropologist S. F. Nadel codified a theory of social structure that was influential in later network analysis. In sociology, the early (1930s) work of Talcott Parsons set the stage for taking a relational approach to understanding social structure. Later, drawing upon Parsons' theory, the work of sociologist Peter Blau provides a strong impetus for analyzing the relational ties of social units with his work on social exchange theory. By the 1970s, a growing number of scholars worked to combine the different tracks and traditions. One group consisted of sociologist Harrison White and his students at the Harvard University Department of Social Relations. Also independently active in the Harvard Social Relations department at the time were Charles Tilly, who focused on networks in political and community sociology and social movements, and Stanley Milgram, who developed the "six degrees of separation" thesis. Mark Granovetter and Barry Wellman are among the former students of White who elaborated and championed the analysis of social networks. Beginning in the late 1990s, social network analysis experienced work by sociologists, political scientists, and physicists such as Duncan J. Watts, Albert-László Barabási, Peter Bearman, Nicholas A. Christakis, James H. Fowler, and others, developing and applying new models and methods to emerging data available about online social networks, as well as "digital traces" regarding face-to-face networks. Levels of analysis In general, social networks are self-organizing, emergent, and complex, such that a globally coherent pattern appears from the local interaction of the elements that make up the system. These patterns become more apparent as network size increases. However, a global network analysis of, for example, all interpersonal relationships in the world is not feasible and is likely to contain so much information as to be uninformative. Practical limitations of computing power, ethics and participant recruitment and payment also limit the scope of a social network analysis. The nuances of a local system may be lost in a large network analysis, hence the quality of information may be more important than its scale for understanding network properties. Thus, social networks are analyzed at the scale relevant to the researcher's theoretical question. Although levels of analysis are not necessarily mutually exclusive, there are three general levels into which networks may fall: micro-level, meso-level, and macro-level. At the micro-level, social network research typically begins with an individual, snowballing as social relationships are traced, or may begin with a small group of individuals in a particular social context. Dyadic level: A dyad is a social relationship between two individuals. Network research on dyads may concentrate on structure of the relationship (e.g. multiplexity, strength), social equality, and tendencies toward reciprocity/mutuality. Triadic level: Add one individual to a dyad, and you have a triad. Research at this level may concentrate on factors such as balance and transitivity, as well as social equality and tendencies toward reciprocity/mutuality. In the balance theory of Fritz Heider the triad is the key to social dynamics. The discord in a rivalrous love triangle is an example of an unbalanced triad, likely to change to a balanced triad by a change in one of the relations. The dynamics of social friendships in society has been modeled by balancing triads. The study is carried forward with the theory of signed graphs. Actor level: The smallest unit of analysis in a social network is an individual in their social setting, i.e., an "actor" or "ego." Egonetwork analysis focuses on network characteristics, such as size, relationship strength, density, centrality, prestige and roles such as isolates, liaisons, and bridges. Such analyses, are most commonly used in the fields of psychology or social psychology, ethnographic kinship analysis or other genealogical studies of relationships between individuals. Subset level: Subset levels of network research problems begin at the micro-level, but may cross over into the meso-level of analysis. Subset level research may focus on distance and reachability, cliques, cohesive subgroups, or other group actions or behavior. In general, meso-level theories begin with a population size that falls between the micro- and macro-levels. However, meso-level may also refer to analyses that are specifically designed to reveal connections between micro- and macro-levels. Meso-level networks are low density and may exhibit causal processes distinct from interpersonal micro-level networks. Organizations: Formal organizations are social groups that distribute tasks for a collective goal. Network research on organizations may focus on either intra-organizational or inter-organizational ties in terms of formal or informal relationships. Intra-organizational networks themselves often contain multiple levels of analysis, especially in larger organizations with multiple branches, franchises or semi-autonomous departments. In these cases, research is often conducted at a work group level and organization level, focusing on the interplay between the two structures. Experiments with networked groups online have documented ways to optimize group-level coordination through diverse interventions, including the addition of autonomous agents to the groups. Randomly distributed networks: Exponential random graph models of social networks became state-of-the-art methods of social network analysis in the 1980s. This framework has the capacity to represent social-structural effects commonly observed in many human social networks, including general degree-based structural effects commonly observed in many human social networks as well as reciprocity and transitivity, and at the node-level, homophily and attribute-based activity and popularity effects, as derived from explicit hypotheses about dependencies among network ties. Parameters are given in terms of the prevalence of small subgraph configurations in the network and can be interpreted as describing the combinations of local social processes from which a given network emerges. These probability models for networks on a given set of actors allow generalization beyond the restrictive dyadic independence assumption of micro-networks, allowing models to be built from theoretical structural foundations of social behavior. Scale-free networks: A scale-free network is a network whose degree distribution follows a power law, at least asymptotically. In network theory a scale-free ideal network is a random network with a degree distribution that unravels the size distribution of social groups. Specific characteristics of scale-free networks vary with the theories and analytical tools used to create them, however, in general, scale-free networks have some common characteristics. One notable characteristic in a scale-free network is the relative commonness of vertices with a degree that greatly exceeds the average. The highest-degree nodes are often called "hubs", and may serve specific purposes in their networks, although this depends greatly on the social context. Another general characteristic of scale-free networks is the clustering coefficient distribution, which decreases as the node degree increases. This distribution also follows a power law. The Barabási model of network evolution shown above is an example of a scale-free network. Rather than tracing interpersonal interactions, macro-level analyses generally trace the outcomes of interactions, such as economic or other resource transfer interactions over a large population. Large-scale networks: Large-scale network is a term somewhat synonymous with "macro-level." It is primarily used in social and behavioral sciences, and in economics. Originally, the term was used extensively in the computer sciences (see large-scale network mapping). Complex networks: Most larger social networks display features of social complexity, which involves substantial non-trivial features of network topology, with patterns of complex connections between elements that are neither purely regular nor purely random (see, complexity science, dynamical system and chaos theory), as do biological, and technological networks. Such complex network features include a heavy tail in the degree distribution, a high clustering coefficient, assortativity or disassortativity among vertices, community structure (see stochastic block model), and hierarchical structure. In the case of agency-directed networks these features also include reciprocity, triad significance profile (TSP, see network motif), and other features. In contrast, many of the mathematical models of networks that have been studied in the past, such as lattices and random graphs, do not show these features. Theoretical links Various theoretical frameworks have been imported for the use of social network analysis. The most prominent of these are Graph theory, Balance theory, Social comparison theory, and more recently, the Social identity approach. Few complete theories have been produced from social network analysis. Two that have are structural role theory and heterophily theory. The basis of Heterophily Theory was the finding in one study that more numerous weak ties can be important in seeking information and innovation, as cliques have a tendency to have more homogeneous opinions as well as share many common traits. This homophilic tendency was the reason for the members of the cliques to be attracted together in the first place. However, being similar, each member of the clique would also know more or less what the other members knew. To find new information or insights, members of the clique will have to look beyond the clique to its other friends and acquaintances. This is what Granovetter called "the strength of weak ties". Structural holes In the context of networks, social capital exists where people have an advantage because of their location in a network. Contacts in a network provide information, opportunities and perspectives that can be beneficial to the central player in the network. Most social structures tend to be characterized by dense clusters of strong connections. Information within these clusters tends to be rather homogeneous and redundant. Non-redundant information is most often obtained through contacts in different clusters. When two separate clusters possess non-redundant information, there is said to be a structural hole between them. Thus, a network that bridges structural holes will provide network benefits that are in some degree additive, rather than overlapping. An ideal network structure has a vine and cluster structure, providing access to many different clusters and structural holes. Networks rich in structural holes are a form of social capital in that they offer information benefits. The main player in a network that bridges structural holes is able to access information from diverse sources and clusters. For example, in business networks, this is beneficial to an individual's career because he is more likely to hear of job openings and opportunities if his network spans a wide range of contacts in different industries/sectors. This concept is similar to Mark Granovetter's theory of weak ties, which rests on the basis that having a broad range of contacts is most effective for job attainment. Structural holes have been widely applied in social network analysis, resulting in applications in a wide range of practical scenarios as well as machine learning-based social prediction. Research clusters Research has used network analysis to examine networks created when artists are exhibited together in museum exhibition. Such networks have been shown to affect an artist's recognition in history and historical narratives, even when controlling for individual accomplishments of the artist. Other work examines how network grouping of artists can affect an individual artist's auction performance. An artist's status has been shown to increase when associated with higher status networks, though this association has diminishing returns over an artist's career. In J.A. Barnes' day, a "community" referred to a specific geographic location and studies of community ties had to do with who talked, associated, traded, and attended church with whom. Today, however, there are extended "online" communities developed through telecommunications devices and social network services. Such devices and services require extensive and ongoing maintenance and analysis, often using network science methods. Community development studies, today, also make extensive use of such methods. Complex networks require methods specific to modelling and interpreting social complexity and complex adaptive systems, including techniques of dynamic network analysis. Mechanisms such as Dual-phase evolution explain how temporal changes in connectivity contribute to the formation of structure in social networks. The study of social networks is being used to examine the nature of interdependencies between actors and the ways in which these are related to outcomes of conflict and cooperation. Areas of study include cooperative behavior among participants in collective actions such as protests; promotion of peaceful behavior, social norms, and public goods within communities through networks of informal governance; the role of social networks in both intrastate conflict and interstate conflict; and social networking among politicians, constituents, and bureaucrats. In criminology and urban sociology, much attention has been paid to the social networks among criminal actors. For example, murders can be seen as a series of exchanges between gangs. Murders can be seen to diffuse outwards from a single source, because weaker gangs cannot afford to kill members of stronger gangs in retaliation, but must commit other violent acts to maintain their reputation for strength. Diffusion of ideas and innovations studies focus on the spread and use of ideas from one actor to another or one culture and another. This line of research seeks to explain why some become "early adopters" of ideas and innovations, and links social network structure with facilitating or impeding the spread of an innovation. A case in point is the social diffusion of linguistic innovation such as neologisms. Experiments and large-scale field trials (e.g., by Nicholas Christakis and collaborators) have shown that cascades of desirable behaviors can be induced in social groups, in settings as diverse as Honduras villages, Indian slums, or in the lab. Still other experiments have documented the experimental induction of social contagion of voting behavior, emotions, risk perception, and commercial products. In demography, the study of social networks has led to new sampling methods for estimating and reaching populations that are hard to enumerate (for example, homeless people or intravenous drug users.) For example, respondent driven sampling is a network-based sampling technique that relies on respondents to a survey recommending further respondents. The field of sociology focuses almost entirely on networks of outcomes of social interactions. More narrowly, economic sociology considers behavioral interactions of individuals and groups through social capital and social "markets". Sociologists, such as Mark Granovetter, have developed core principles about the interactions of social structure, information, ability to punish or reward, and trust that frequently recur in their analyses of political, economic and other institutions. Granovetter examines how social structures and social networks can affect economic outcomes like hiring, price, productivity and innovation and describes sociologists' contributions to analyzing the impact of social structure and networks on the economy. Analysis of social networks is increasingly incorporated into health care analytics, not only in epidemiological studies but also in models of patient communication and education, disease prevention, mental health diagnosis and treatment, and in the study of health care organizations and systems. Human ecology is an interdisciplinary and transdisciplinary study of the relationship between humans and their natural, social, and built environments. The scientific philosophy of human ecology has a diffuse history with connections to geography, sociology, psychology, anthropology, zoology, and natural ecology. In the study of literary systems, network analysis has been applied by Anheier, Gerhards and Romo, De Nooy, Senekal, and Lotker, to study various aspects of how literature functions. The basic premise is that polysystem theory, which has been around since the writings of Even-Zohar, can be integrated with network theory and the relationships between different actors in the literary network, e.g. writers, critics, publishers, literary histories, etc., can be mapped using visualization from SNA. Research studies of formal or informal organization relationships, organizational communication, economics, economic sociology, and other resource transfers. Social networks have also been used to examine how organizations interact with each other, characterizing the many informal connections that link executives together, as well as associations and connections between individual employees at different organizations. Many organizational social network studies focus on teams. Within team network studies, research assesses, for example, the predictors and outcomes of centrality and power, density and centralization of team instrumental and expressive ties, and the role of between-team networks. Intra-organizational networks have been found to affect organizational commitment, organizational identification, interpersonal citizenship behaviour. Social capital is a form of economic and cultural capital in which social networks are central, transactions are marked by reciprocity, trust, and cooperation, and market agents produce goods and services not mainly for themselves, but for a common good. Social capital is split into three dimensions: the structural, the relational and the cognitive dimension. The structural dimension describes how partners interact with each other and which specific partners meet in a social network. Also, the structural dimension of social capital indicates the level of ties among organizations. This dimension is highly connected to the relational dimension which refers to trustworthiness, norms, expectations and identifications of the bonds between partners. The relational dimension explains the nature of these ties which is mainly illustrated by the level of trust accorded to the network of organizations. The cognitive dimension analyses the extent to which organizations share common goals and objectives as a result of their ties and interactions. Social capital is a sociological concept about the value of social relations and the role of cooperation and confidence to achieve positive outcomes. The term refers to the value one can get from their social ties. For example, newly arrived immigrants can make use of their social ties to established migrants to acquire jobs they may otherwise have trouble getting (e.g., because of unfamiliarity with the local language). A positive relationship exists between social capital and the intensity of social network use. In a dynamic framework, higher activity in a network feeds into higher social capital which itself encourages more activity. This particular cluster focuses on brand-image and promotional strategy effectiveness, taking into account the impact of customer participation on sales and brand-image. This is gauged through techniques such as sentiment analysis which rely on mathematical areas of study such as data mining and analytics. This area of research produces vast numbers of commercial applications as the main goal of any study is to understand consumer behaviour and drive sales. In many organizations, members tend to focus their activities inside their own groups, which stifles creativity and restricts opportunities. A player whose network bridges structural holes has an advantage in detecting and developing rewarding opportunities. Such a player can mobilize social capital by acting as a "broker" of information between two clusters that otherwise would not have been in contact, thus providing access to new ideas, opinions and opportunities. British philosopher and political economist John Stuart Mill, writes, "it is hardly possible to overrate the value of placing human beings in contact with persons dissimilar to themselves.... Such communication [is] one of the primary sources of progress." Thus, a player with a network rich in structural holes can add value to an organization through new ideas and opportunities. This in turn, helps an individual's career development and advancement. A social capital broker also reaps control benefits of being the facilitator of information flow between contacts. Full communication with exploratory mindsets and information exchange generated by dynamically alternating positions in a social network promotes creative and deep thinking. In the case of consulting firm Eden McCallum, the founders were able to advance their careers by bridging their connections with former big three consulting firm consultants and mid-size industry firms. By bridging structural holes and mobilizing social capital, players can advance their careers by executing new opportunities between contacts. There has been research that both substantiates and refutes the benefits of information brokerage. A study of high tech Chinese firms by Zhixing Xiao found that the control benefits of structural holes are "dissonant to the dominant firm-wide spirit of cooperation and the information benefits cannot materialize due to the communal sharing values" of such organizations. However, this study only analyzed Chinese firms, which tend to have strong communal sharing values. Information and control benefits of structural holes are still valuable in firms that are not quite as inclusive and cooperative on the firm-wide level. In 2004, Ronald Burt studied 673 managers who ran the supply chain for one of America's largest electronics companies. He found that managers who often discussed issues with other groups were better paid, received more positive job evaluations and were more likely to be promoted. Thus, bridging structural holes can be beneficial to an organization, and in turn, to an individual's career. Computer networks combined with social networking software produce a new medium for social interaction. A relationship over a computerized social networking service can be characterized by context, direction, and strength. The content of a relation refers to the resource that is exchanged. In a computer-mediated communication context, social pairs exchange different kinds of information, including sending a data file or a computer program as well as providing emotional support or arranging a meeting. With the rise of electronic commerce, information exchanged may also correspond to exchanges of money, goods or services in the "real" world. Social network analysis methods have become essential to examining these types of computer mediated communication. In addition, the sheer size and the volatile nature of social media has given rise to new network metrics. A key concern with networks extracted from social media is the lack of robustness of network metrics given missing data. Based on the pattern of homophily, ties between people are most likely to occur between nodes that are most similar to each other, or within neighbourhood segregation, individuals are most likely to inhabit the same regional areas as other individuals who are like them. Therefore, social networks can be used as a tool to measure the degree of segregation or homophily within a social network. Social Networks can both be used to simulate the process of homophily but it can also serve as a measure of level of exposure of different groups to each other within a current social network of individuals in a certain area. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/PlayStation_(console)#cite_note-FOOTNOTEAsakura2000103-247] | [TOKENS: 10728] |
Contents PlayStation (console) The PlayStation[a] (codenamed PSX, abbreviated as PS, and retroactively PS1 or PS one) is a home video game console developed and marketed by Sony Computer Entertainment. It was released in Japan on 3 December 1994, followed by North America on 9 September 1995, Europe on 29 September 1995, and other regions following thereafter. As a fifth-generation console, the PlayStation primarily competed with the Nintendo 64 and the Sega Saturn. Sony began developing the PlayStation after a failed venture with Nintendo to create a CD-ROM peripheral for the Super Nintendo Entertainment System in the early 1990s. The console was primarily designed by Ken Kutaragi and Sony Computer Entertainment in Japan, while additional development was outsourced in the United Kingdom. An emphasis on 3D polygon graphics was placed at the forefront of the console's design. PlayStation game production was designed to be streamlined and inclusive, enticing the support of many third party developers. The console proved popular for its extensive game library, popular franchises, low retail price, and aggressive youth marketing which advertised it as the preferable console for adolescents and adults. Critically acclaimed games that defined the console include Gran Turismo, Crash Bandicoot, Spyro the Dragon, Tomb Raider, Resident Evil, Metal Gear Solid, Tekken 3, and Final Fantasy VII. Sony ceased production of the PlayStation on 23 March 2006—over eleven years after it had been released, and in the same year the PlayStation 3 debuted. More than 4,000 PlayStation games were released, with cumulative sales of 962 million units. The PlayStation signaled Sony's rise to power in the video game industry. It received acclaim and sold strongly; in less than a decade, it became the first computer entertainment platform to ship over 100 million units. Its use of compact discs heralded the game industry's transition from cartridges. The PlayStation's success led to a line of successors, beginning with the PlayStation 2 in 2000. In the same year, Sony released a smaller and cheaper model, the PS one. History The PlayStation was conceived by Ken Kutaragi, a Sony executive who managed a hardware engineering division and was later dubbed "the Father of the PlayStation". Kutaragi's interest in working with video games stemmed from seeing his daughter play games on Nintendo's Famicom. Kutaragi convinced Nintendo to use his SPC-700 sound processor in the Super Nintendo Entertainment System (SNES) through a demonstration of the processor's capabilities. His willingness to work with Nintendo was derived from both his admiration of the Famicom and conviction in video game consoles becoming the main home-use entertainment systems. Although Kutaragi was nearly fired because he worked with Nintendo without Sony's knowledge, president Norio Ohga recognised the potential in Kutaragi's chip and decided to keep him as a protégé. The inception of the PlayStation dates back to a 1988 joint venture between Nintendo and Sony. Nintendo had produced floppy disk technology to complement cartridges in the form of the Family Computer Disk System, and wanted to continue this complementary storage strategy for the SNES. Since Sony was already contracted to produce the SPC-700 sound processor for the SNES, Nintendo contracted Sony to develop a CD-ROM add-on, tentatively titled the "Play Station" or "SNES-CD". The PlayStation name had already been trademarked by Yamaha, but Nobuyuki Idei liked it so much that he agreed to acquire it for an undisclosed sum rather than search for an alternative. Sony was keen to obtain a foothold in the rapidly expanding video game market. Having been the primary manufacturer of the MSX home computer format, Sony had wanted to use their experience in consumer electronics to produce their own video game hardware. Although the initial agreement between Nintendo and Sony was about producing a CD-ROM drive add-on, Sony had also planned to develop a SNES-compatible Sony-branded console. This iteration was intended to be more of a home entertainment system, playing both SNES cartridges and a new CD format named the "Super Disc", which Sony would design. Under the agreement, Sony would retain sole international rights to every Super Disc game, giving them a large degree of control despite Nintendo's leading position in the video game market. Furthermore, Sony would also be the sole benefactor of licensing related to music and film software that it had been aggressively pursuing as a secondary application. The Play Station was to be announced at the 1991 Consumer Electronics Show (CES) in Las Vegas. However, Nintendo president Hiroshi Yamauchi was wary of Sony's increasing leverage at this point and deemed the original 1988 contract unacceptable upon realising it essentially handed Sony control over all games written on the SNES CD-ROM format. Although Nintendo was dominant in the video game market, Sony possessed a superior research and development department. Wanting to protect Nintendo's existing licensing structure, Yamauchi cancelled all plans for the joint Nintendo–Sony SNES CD attachment without telling Sony. He sent Nintendo of America president Minoru Arakawa (his son-in-law) and chairman Howard Lincoln to Amsterdam to form a more favourable contract with Dutch conglomerate Philips, Sony's rival. This contract would give Nintendo total control over their licences on all Philips-produced machines. Kutaragi and Nobuyuki Idei, Sony's director of public relations at the time, learned of Nintendo's actions two days before the CES was due to begin. Kutaragi telephoned numerous contacts, including Philips, to no avail. On the first day of the CES, Sony announced their partnership with Nintendo and their new console, the Play Station. At 9 am on the next day, in what has been called "the greatest ever betrayal" in the industry, Howard Lincoln stepped onto the stage and revealed that Nintendo was now allied with Philips and would abandon their work with Sony. Incensed by Nintendo's renouncement, Ohga and Kutaragi decided that Sony would develop their own console. Nintendo's contract-breaking was met with consternation in the Japanese business community, as they had broken an "unwritten law" of native companies not turning against each other in favour of foreign ones. Sony's American branch considered allying with Sega to produce a CD-ROM-based machine called the Sega Multimedia Entertainment System, but the Sega board of directors in Tokyo vetoed the idea when Sega of America CEO Tom Kalinske presented them the proposal. Kalinske recalled them saying: "That's a stupid idea, Sony doesn't know how to make hardware. They don't know how to make software either. Why would we want to do this?" Sony halted their research, but decided to develop what it had developed with Nintendo and Sega into a console based on the SNES. Despite the tumultuous events at the 1991 CES, negotiations between Nintendo and Sony were still ongoing. A deal was proposed: the Play Station would still have a port for SNES games, on the condition that it would still use Kutaragi's audio chip and that Nintendo would own the rights and receive the bulk of the profits. Roughly two hundred prototype machines were created, and some software entered development. Many within Sony were still opposed to their involvement in the video game industry, with some resenting Kutaragi for jeopardising the company. Kutaragi remained adamant that Sony not retreat from the growing industry and that a deal with Nintendo would never work. Knowing that they had to take decisive action, Sony severed all ties with Nintendo on 4 May 1992. To determine the fate of the PlayStation project, Ohga chaired a meeting in June 1992, consisting of Kutaragi and several senior Sony board members. Kutaragi unveiled a proprietary CD-ROM-based system he had been secretly working on which played games with immersive 3D graphics. Kutaragi was confident that his LSI chip could accommodate one million logic gates, which exceeded the capabilities of Sony's semiconductor division at the time. Despite gaining Ohga's enthusiasm, there remained opposition from a majority present at the meeting. Older Sony executives also opposed it, who saw Nintendo and Sega as "toy" manufacturers. The opposers felt the game industry was too culturally offbeat and asserted that Sony should remain a central player in the audiovisual industry, where companies were familiar with one another and could conduct "civili[s]ed" business negotiations. After Kutaragi reminded him of the humiliation he suffered from Nintendo, Ohga retained the project and became one of Kutaragi's most staunch supporters. Ohga shifted Kutaragi and nine of his team from Sony's main headquarters to Sony Music Entertainment Japan (SMEJ), a subsidiary of the main Sony group, so as to retain the project and maintain relationships with Philips for the MMCD development project. The involvement of SMEJ proved crucial to the PlayStation's early development as the process of manufacturing games on CD-ROM format was similar to that used for audio CDs, with which Sony's music division had considerable experience. While at SMEJ, Kutaragi worked with Epic/Sony Records founder Shigeo Maruyama and Akira Sato; both later became vice-presidents of the division that ran the PlayStation business. Sony Computer Entertainment (SCE) was jointly established by Sony and SMEJ to handle the company's ventures into the video game industry. On 27 October 1993, Sony publicly announced that it was entering the game console market with the PlayStation. According to Maruyama, there was uncertainty over whether the console should primarily focus on 2D, sprite-based graphics or 3D polygon graphics. After Sony witnessed the success of Sega's Virtua Fighter (1993) in Japanese arcades, the direction of the PlayStation became "instantly clear" and 3D polygon graphics became the console's primary focus. SCE president Teruhisa Tokunaka expressed gratitude for Sega's timely release of Virtua Fighter as it proved "just at the right time" that making games with 3D imagery was possible. Maruyama claimed that Sony further wanted to emphasise the new console's ability to utilise redbook audio from the CD-ROM format in its games alongside high quality visuals and gameplay. Wishing to distance the project from the failed enterprise with Nintendo, Sony initially branded the PlayStation the "PlayStation X" (PSX). Sony formed their European division and North American division, known as Sony Computer Entertainment Europe (SCEE) and Sony Computer Entertainment America (SCEA), in January and May 1995. The divisions planned to market the new console under the alternative branding "PSX" following the negative feedback regarding "PlayStation" in focus group studies. Early advertising prior to the console's launch in North America referenced PSX, but the term was scrapped before launch. The console was not marketed with Sony's name in contrast to Nintendo's consoles. According to Phil Harrison, much of Sony's upper management feared that the Sony brand would be tarnished if associated with the console, which they considered a "toy". Since Sony had no experience in game development, it had to rely on the support of third-party game developers. This was in contrast to Sega and Nintendo, which had versatile and well-equipped in-house software divisions for their arcade games and could easily port successful games to their home consoles. Recent consoles like the Atari Jaguar and 3DO suffered low sales due to a lack of developer support, prompting Sony to redouble their efforts in gaining the endorsement of arcade-savvy developers. A team from Epic Sony visited more than a hundred companies throughout Japan in May 1993 in hopes of attracting game creators with the PlayStation's technological appeal. Sony found that many disliked Nintendo's practices, such as favouring their own games over others. Through a series of negotiations, Sony acquired initial support from Namco, Konami, and Williams Entertainment, as well as 250 other development teams in Japan alone. Namco in particular was interested in developing for PlayStation since Namco rivalled Sega in the arcade market. Attaining these companies secured influential games such as Ridge Racer (1993) and Mortal Kombat 3 (1995), Ridge Racer being one of the most popular arcade games at the time, and it was already confirmed behind closed doors that it would be the PlayStation's first game by December 1993, despite Namco being a longstanding Nintendo developer. Namco's research managing director Shegeichi Nakamura met with Kutaragi in 1993 to discuss the preliminary PlayStation specifications, with Namco subsequently basing the Namco System 11 arcade board on PlayStation hardware and developing Tekken to compete with Virtua Fighter. The System 11 launched in arcades several months before the PlayStation's release, with the arcade release of Tekken in September 1994. Despite securing the support of various Japanese studios, Sony had no developers of their own by the time the PlayStation was in development. This changed in 1993 when Sony acquired the Liverpudlian company Psygnosis (later renamed SCE Liverpool) for US$48 million, securing their first in-house development team. The acquisition meant that Sony could have more launch games ready for the PlayStation's release in Europe and North America. Ian Hetherington, Psygnosis' co-founder, was disappointed after receiving early builds of the PlayStation and recalled that the console "was not fit for purpose" until his team got involved with it. Hetherington frequently clashed with Sony executives over broader ideas; at one point it was suggested that a television with a built-in PlayStation be produced. In the months leading up to the PlayStation's launch, Psygnosis had around 500 full-time staff working on games and assisting with software development. The purchase of Psygnosis marked another turning point for the PlayStation as it played a vital role in creating the console's development kits. While Sony had provided MIPS R4000-based Sony NEWS workstations for PlayStation development, Psygnosis employees disliked the thought of developing on these expensive workstations and asked Bristol-based SN Systems to create an alternative PC-based development system. Andy Beveridge and Martin Day, owners of SN Systems, had previously supplied development hardware for other consoles such as the Mega Drive, Atari ST, and the SNES. When Psygnosis arranged an audience for SN Systems with Sony's Japanese executives at the January 1994 CES in Las Vegas, Beveridge and Day presented their prototype of the condensed development kit, which could run on an ordinary personal computer with two extension boards. Impressed, Sony decided to abandon their plans for a workstation-based development system in favour of SN Systems's, thus securing a cheaper and more efficient method for designing software. An order of over 600 systems followed, and SN Systems supplied Sony with additional software such as an assembler, linker, and a debugger. SN Systems produced development kits for future PlayStation systems, including the PlayStation 2 and was bought out by Sony in 2005. Sony strived to make game production as streamlined and inclusive as possible, in contrast to the relatively isolated approach of Sega and Nintendo. Phil Harrison, representative director of SCEE, believed that Sony's emphasis on developer assistance reduced most time-consuming aspects of development. As well as providing programming libraries, SCE headquarters in London, California, and Tokyo housed technical support teams that could work closely with third-party developers if needed. Sony did not favour their own over non-Sony products, unlike Nintendo; Peter Molyneux of Bullfrog Productions admired Sony's open-handed approach to software developers and lauded their decision to use PCs as a development platform, remarking that "[it was] like being released from jail in terms of the freedom you have". Another strategy that helped attract software developers was the PlayStation's use of the CD-ROM format instead of traditional cartridges. Nintendo cartridges were expensive to manufacture, and the company controlled all production, prioritising their own games, while inexpensive compact disc manufacturing occurred at dozens of locations around the world. The PlayStation's architecture and interconnectability with PCs was beneficial to many software developers. The use of the programming language C proved useful, as it safeguarded future compatibility of the machine should developers decide to make further hardware revisions. Despite the inherent flexibility, some developers found themselves restricted due to the console's lack of RAM. While working on beta builds of the PlayStation, Molyneux observed that its MIPS processor was not "quite as bullish" compared to that of a fast PC and said that it took his team two weeks to port their PC code to the PlayStation development kits and another fortnight to achieve a four-fold speed increase. An engineer from Ocean Software, one of Europe's largest game developers at the time, thought that allocating RAM was a challenging aspect given the 3.5 megabyte restriction. Kutaragi said that while it would have been easy to double the amount of RAM for the PlayStation, the development team refrained from doing so to keep the retail cost down. Kutaragi saw the biggest challenge in developing the system to be balancing the conflicting goals of high performance, low cost, and being easy to program for, and felt he and his team were successful in this regard. Its technical specifications were finalised in 1993 and its design during 1994. The PlayStation name and its final design were confirmed during a press conference on May 10, 1994, although the price and release dates had not been disclosed yet. Sony released the PlayStation in Japan on 3 December 1994, a week after the release of the Sega Saturn, at a price of ¥39,800. Sales in Japan began with a "stunning" success with long queues in shops. Ohga later recalled that he realised how important PlayStation had become for Sony when friends and relatives begged for consoles for their children. PlayStation sold 100,000 units on the first day and two million units within six months, although the Saturn outsold the PlayStation in the first few weeks due to the success of Virtua Fighter. By the end of 1994, 300,000 PlayStation units were sold in Japan compared to 500,000 Saturn units. A grey market emerged for PlayStations shipped from Japan to North America and Europe, with buyers of such consoles paying up to £700. "When September 1995 arrived and Sony's Playstation roared out of the gate, things immediately felt different than [sic] they did with the Saturn launch earlier that year. Sega dropped the Saturn $100 to match the Playstation's $299 debut price, but sales weren't even close—Playstations flew out the door as fast as we could get them in stock. Before the release in North America, Sega and Sony presented their consoles at the first Electronic Entertainment Expo (E3) in Los Angeles on 11 May 1995. At their keynote presentation, Sega of America CEO Tom Kalinske revealed that their Saturn console would be released immediately to select retailers at a price of $399. Next came Sony's turn: Olaf Olafsson, the head of SCEA, summoned Steve Race, the head of development, to the conference stage, who said "$299" and left the audience with a round of applause. The attention to the Sony conference was further bolstered by the surprise appearance of Michael Jackson and the showcase of highly anticipated games, including Wipeout (1995), Ridge Racer and Tekken (1994). In addition, Sony announced that no games would be bundled with the console. Although the Saturn had released early in the United States to gain an advantage over the PlayStation, the surprise launch upset many retailers who were not informed in time, harming sales. Some retailers such as KB Toys responded by dropping the Saturn entirely. The PlayStation went on sale in North America on 9 September 1995. It sold more units within two days than the Saturn had in five months, with almost all of the initial shipment of 100,000 units sold in advance and shops across the country running out of consoles and accessories. The well-received Ridge Racer contributed to the PlayStation's early success, — with some critics considering it superior to Sega's arcade counterpart Daytona USA (1994) — as did Battle Arena Toshinden (1995). There were over 100,000 pre-orders placed and 17 games available on the market by the time of the PlayStation's American launch, in comparison to the Saturn's six launch games. The PlayStation released in Europe on 29 September 1995 and in Australia on 15 November 1995. By November it had already outsold the Saturn by three to one in the United Kingdom, where Sony had allocated a £20 million marketing budget during the Christmas season compared to Sega's £4 million. Sony found early success in the United Kingdom by securing listings with independent shop owners as well as prominent High Street chains such as Comet and Argos. Within its first year, the PlayStation secured over 20% of the entire American video game market. From September to the end of 1995, sales in the United States amounted to 800,000 units, giving the PlayStation a commanding lead over the other fifth-generation consoles,[b] though the SNES and Mega Drive from the fourth generation still outsold it. Sony reported that the attach rate of sold games and consoles was four to one. To meet increasing demand, Sony chartered jumbo jets and ramped up production in Europe and North America. By early 1996, the PlayStation had grossed $2 billion (equivalent to $4.106 billion 2025) from worldwide hardware and software sales. By late 1996, sales in Europe totalled 2.2 million units, including 700,000 in the UK. Approximately 400 PlayStation games were in development, compared to around 200 games being developed for the Saturn and 60 for the Nintendo 64. In India, the PlayStation was launched in test market during 1999–2000 across Sony showrooms, selling 100 units. Sony finally launched the console (PS One model) countrywide on 24 January 2002 with the price of Rs 7,990 and 26 games available from start. PlayStation was also doing well in markets where it was never officially released. For example, in Brazil, due to the registration of the trademark by a third company, the console could not be released, which was why the market was taken over by the officially distributed Sega Saturn during the first period, but as the Sega console withdraws, PlayStation imports and large piracy increased. In another market, China, the most popular 32-bit console was Sega Saturn, but after leaving the market, PlayStation grown with a base of 300,000 users until January 2000, although Sony China did not have plans to release it. The PlayStation was backed by a successful marketing campaign, allowing Sony to gain an early foothold in Europe and North America. Initially, PlayStation demographics were skewed towards adults, but the audience broadened after the first price drop. While the Saturn was positioned towards 18- to 34-year-olds, the PlayStation was initially marketed exclusively towards teenagers. Executives from both Sony and Sega reasoned that because younger players typically looked up to older, more experienced players, advertising targeted at teens and adults would draw them in too. Additionally, Sony found that adults reacted best to advertising aimed at teenagers; Lee Clow surmised that people who started to grow into adulthood regressed and became "17 again" when they played video games. The console was marketed with advertising slogans stylised as "LIVE IN YUR WRLD. PLY IN URS" (Live in Your World. Play in Ours.) and "U R NOT E" (red E). The four geometric shapes were derived from the symbols for the four buttons on the controller. Clow thought that by invoking such provocative statements, gamers would respond to the contrary and say "'Bullshit. Let me show you how ready I am.'" As the console's appeal enlarged, Sony's marketing efforts broadened from their earlier focus on mature players to specifically target younger children as well. Shortly after the PlayStation's release in Europe, Sony tasked marketing manager Geoff Glendenning with assessing the desires of a new target audience. Sceptical over Nintendo and Sega's reliance on television campaigns, Glendenning theorised that young adults transitioning from fourth-generation consoles would feel neglected by marketing directed at children and teenagers. Recognising the influence early 1990s underground clubbing and rave culture had on young people, especially in the United Kingdom, Glendenning felt that the culture had become mainstream enough to help cultivate PlayStation's emerging identity. Sony partnered with prominent nightclub owners such as Ministry of Sound and festival promoters to organise dedicated PlayStation areas where demonstrations of select games could be tested. Sheffield-based graphic design studio The Designers Republic was contracted by Sony to produce promotional materials aimed at a fashionable, club-going audience. Psygnosis' Wipeout in particular became associated with nightclub culture as it was widely featured in venues. By 1997, there were 52 nightclubs in the United Kingdom with dedicated PlayStation rooms. Glendenning recalled that he had discreetly used at least £100,000 a year in slush fund money to invest in impromptu marketing. In 1996, Sony expanded their CD production facilities in the United States due to the high demand for PlayStation games, increasing their monthly output from 4 million discs to 6.5 million discs. This was necessary because PlayStation sales were running at twice the rate of Saturn sales, and its lead dramatically increased when both consoles dropped in price to $199 that year. The PlayStation also outsold the Saturn at a similar ratio in Europe during 1996, with 2.2 million consoles sold in the region by the end of the year. Sales figures for PlayStation hardware and software only increased following the launch of the Nintendo 64. Tokunaka speculated that the Nintendo 64 launch had actually helped PlayStation sales by raising public awareness of the gaming market through Nintendo's added marketing efforts. Despite this, the PlayStation took longer to achieve dominance in Japan. Tokunaka said that, even after the PlayStation and Saturn had been on the market for nearly two years, the competition between them was still "very close", and neither console had led in sales for any meaningful length of time. By 1998, Sega, encouraged by their declining market share and significant financial losses, launched the Dreamcast as a last-ditch attempt to stay in the industry. Although its launch was successful, the technically superior 128-bit console was unable to subdue Sony's dominance in the industry. Sony still held 60% of the overall video game market share in North America at the end of 1999. Sega's initial confidence in their new console was undermined when Japanese sales were lower than expected, with disgruntled Japanese consumers reportedly returning their Dreamcasts in exchange for PlayStation software. On 2 March 1999, Sony officially revealed details of the PlayStation 2, which Kutaragi announced would feature a graphics processor designed to push more raw polygons than any console in history, effectively rivalling most supercomputers. The PlayStation continued to sell strongly at the turn of the new millennium: in June 2000, Sony released the PSOne, a smaller, redesigned variant which went on to outsell all other consoles in that year, including the PlayStation 2. In 2005, PlayStation became the first console to ship 100 million units with the PlayStation 2 later achieving this faster than its predecessor. The combined successes of both PlayStation consoles led to Sega retiring the Dreamcast in 2001, and abandoning the console business entirely. The PlayStation was eventually discontinued on 23 March 2006—over eleven years after its release, and less than a year before the debut of the PlayStation 3. Hardware The main microprocessor is a R3000 CPU made by LSI Logic operating at a clock rate of 33.8688 MHz and 30 MIPS. This 32-bit CPU relies heavily on the "cop2" 3D and matrix math coprocessor on the same die to provide the necessary speed to render complex 3D graphics. The role of the separate GPU chip is to draw 2D polygons and apply shading and textures to them: the rasterisation stage of the graphics pipeline. Sony's custom 16-bit sound chip supports ADPCM sources with up to 24 sound channels and offers a sampling rate of up to 44.1 kHz and music sequencing. It features 2 MB of main RAM, with an additional 1 MB of video RAM. The PlayStation has a maximum colour depth of 16.7 million true colours with 32 levels of transparency and unlimited colour look-up tables. The PlayStation can output composite, S-Video or RGB video signals through its AV Multi connector (with older models also having RCA connectors for composite), displaying resolutions from 256×224 to 640×480 pixels. Different games can use different resolutions. Earlier models also had proprietary parallel and serial ports that could be used to connect accessories or multiple consoles together; these were later removed due to a lack of usage. The PlayStation uses a proprietary video compression unit, MDEC, which is integrated into the CPU and allows for the presentation of full motion video at a higher quality than other consoles of its generation. Unusual for the time, the PlayStation lacks a dedicated 2D graphics processor; 2D elements are instead calculated as polygons by the Geometry Transfer Engine (GTE) so that they can be processed and displayed on screen by the GPU. While running, the GPU can also generate a total of 4,000 sprites and 180,000 polygons per second, in addition to 360,000 per second flat-shaded. The PlayStation went through a number of variants during its production run. Externally, the most notable change was the gradual reduction in the number of external connectors from the rear of the unit. This started with the original Japanese launch units; the SCPH-1000, released on 3 December 1994, was the only model that had an S-Video port, as it was removed from the next model. Subsequent models saw a reduction in number of parallel ports, with the final version only retaining one serial port. Sony marketed a development kit for amateur developers known as the Net Yaroze (meaning "Let's do it together" in Japanese). It was launched in June 1996 in Japan, and following public interest, was released the next year in other countries. The Net Yaroze allowed hobbyists to create their own games and upload them via an online forum run by Sony. The console was only available to buy through an ordering service and with the necessary documentation and software to program PlayStation games and applications through C programming compilers. On 7 July 2000, Sony released the PS One (stylised as "PS one" or "PSone"), a smaller, redesigned version of the original PlayStation. It was the highest-selling console through the end of the year, outselling all other consoles—including the PlayStation 2. In 2002, Sony released a 5-inch (130 mm) LCD screen add-on for the PS One, referred to as the "Combo pack". It also included a car cigarette lighter adaptor adding an extra layer of portability. Production of the LCD "Combo Pack" ceased in 2004, when the popularity of the PlayStation began to wane in markets outside Japan. A total of 28.15 million PS One units had been sold by the time it was discontinued in March 2006. Three iterations of the PlayStation's controller were released over the console's lifespan. The first controller, the PlayStation controller, was released alongside the PlayStation in December 1994. It features four individual directional buttons (as opposed to a conventional D-pad), a pair of shoulder buttons on both sides, Start and Select buttons in the centre, and four face buttons consisting of simple geometric shapes: a green triangle, red circle, blue cross, and a pink square (, , , ). Rather than depicting traditionally used letters or numbers onto its buttons, the PlayStation controller established a trademark which would be incorporated heavily into the PlayStation brand. Teiyu Goto, the designer of the original PlayStation controller, said that the circle and cross represent "yes" and "no", respectively (though this layout is reversed in Western versions); the triangle symbolises a point of view and the square is equated to a sheet of paper to be used to access menus. The European and North American models of the original PlayStation controllers are roughly 10% larger than its Japanese variant, to account for the fact the average person in those regions has larger hands than the average Japanese person. Sony's first analogue gamepad, the PlayStation Analog Joystick (often erroneously referred to as the "Sony Flightstick"), was first released in Japan in April 1996. Featuring two parallel joysticks, it uses potentiometer technology previously used on consoles such as the Vectrex; instead of relying on binary eight-way switches, the controller detects minute angular changes through the entire range of motion. The stick also features a thumb-operated digital hat switch on the right joystick, corresponding to the traditional D-pad, and used for instances when simple digital movements were necessary. The Analog Joystick sold poorly in Japan due to its high cost and cumbersome size. The increasing popularity of 3D games prompted Sony to add analogue sticks to its controller design to give users more freedom over their movements in virtual 3D environments. The first official analogue controller, the Dual Analog Controller, was revealed to the public in a small glass booth at the 1996 PlayStation Expo in Japan, and released in April 1997 to coincide with the Japanese releases of analogue-capable games Tobal 2 and Bushido Blade. In addition to the two analogue sticks (which also introduced two new buttons mapped to clicking in the analogue sticks), the Dual Analog controller features an "Analog" button and LED beneath the "Start" and "Select" buttons which toggles analogue functionality on or off. The controller also features rumble support, though Sony decided that haptic feedback would be removed from all overseas iterations before the United States release. A Sony spokesman stated that the feature was removed for "manufacturing reasons", although rumours circulated that Nintendo had attempted to legally block the release of the controller outside Japan due to similarities with the Nintendo 64 controller's Rumble Pak. However, a Nintendo spokesman denied that Nintendo took legal action. Next Generation's Chris Charla theorised that Sony dropped vibration feedback to keep the price of the controller down. In November 1997, Sony introduced the DualShock controller. Its name derives from its use of two (dual) vibration motors (shock). Unlike its predecessor, its analogue sticks feature textured rubber grips, longer handles, slightly different shoulder buttons and has rumble feedback included as standard on all versions. The DualShock later replaced its predecessors as the default controller. Sony released a series of peripherals to add extra layers of functionality to the PlayStation. Such peripherals include memory cards, the PlayStation Mouse, the PlayStation Link Cable, the Multiplayer Adapter (a four-player multitap), the Memory Drive (a disk drive for 3.5-inch floppy disks), the GunCon (a light gun), and the Glasstron (a monoscopic head-mounted display). Released exclusively in Japan, the PocketStation is a memory card peripheral which acts as a miniature personal digital assistant. The device features a monochrome liquid crystal display (LCD), infrared communication capability, a real-time clock, built-in flash memory, and sound capability. Sharing similarities with the Dreamcast's VMU peripheral, the PocketStation was typically distributed with certain PlayStation games, enhancing them with added features. The PocketStation proved popular in Japan, selling over five million units. Sony planned to release the peripheral outside Japan but the release was cancelled, despite receiving promotion in Europe and North America. In addition to playing games, most PlayStation models are equipped to play CD-Audio. The Asian model SCPH-5903 can also play Video CDs. Like most CD players, the PlayStation can play songs in a programmed order, shuffle the playback order of the disc and repeat one song or the entire disc. Later PlayStation models use a music visualisation function called SoundScope. This function, as well as a memory card manager, is accessed by starting the console without either inserting a game or closing the CD tray, thereby accessing a graphical user interface (GUI) for the PlayStation BIOS. The GUI for the PS One and PlayStation differ depending on the firmware version: the original PlayStation GUI had a dark blue background with rainbow graffiti used as buttons, while the early PAL PlayStation and PS One GUI had a grey blocked background with two icons in the middle. PlayStation emulation is versatile and can be run on numerous modern devices. Bleem! was a commercial emulator which was released for IBM-compatible PCs and the Dreamcast in 1999. It was notable for being aggressively marketed during the PlayStation's lifetime, and was the centre of multiple controversial lawsuits filed by Sony. Bleem! was programmed in assembly language, which allowed it to emulate PlayStation games with improved visual fidelity, enhanced resolutions, and filtered textures that was not possible on original hardware. Sony sued Bleem! two days after its release, citing copyright infringement and accusing the company of engaging in unfair competition and patent infringement by allowing use of PlayStation BIOSs on a Sega console. Bleem! were subsequently forced to shut down in November 2001. Sony was aware that using CDs for game distribution could have left games vulnerable to piracy, due to the growing popularity of CD-R and optical disc drives with burning capability. To preclude illegal copying, a proprietary process for PlayStation disc manufacturing was developed that, in conjunction with an augmented optical drive in Tiger H/E assembly, prevented burned copies of games from booting on an unmodified console. Specifically, all genuine PlayStation discs were printed with a small section of deliberate irregular data, which the PlayStation's optical pick-up was capable of detecting and decoding. Consoles would not boot game discs without a specific wobble frequency contained in the data of the disc pregap sector (the same system was also used to encode discs' regional lockouts). This signal was within Red Book CD tolerances, so PlayStation discs' actual content could still be read by a conventional disc drive; however, the disc drive could not detect the wobble frequency (therefore duplicating the discs omitting it), since the laser pick-up system of any optical disc drive would interpret this wobble as an oscillation of the disc surface and compensate for it in the reading process. Early PlayStations, particularly early 1000 models, experience skipping full-motion video or physical "ticking" noises from the unit. The problems stem from poorly placed vents leading to overheating in some environments, causing the plastic mouldings inside the console to warp slightly and create knock-on effects with the laser assembly. The solution is to sit the console on a surface which dissipates heat efficiently in a well vented area or raise the unit up slightly from its resting surface. Sony representatives also recommended unplugging the PlayStation when it is not in use, as the system draws in a small amount of power (and therefore heat) even when turned off. The first batch of PlayStations use a KSM-440AAM laser unit, whose case and movable parts are all built out of plastic. Over time, the plastic lens sled rail wears out—usually unevenly—due to friction. The placement of the laser unit close to the power supply accelerates wear, due to the additional heat, which makes the plastic more vulnerable to friction. Eventually, one side of the lens sled will become so worn that the laser can tilt, no longer pointing directly at the CD; after this, games will no longer load due to data read errors. Sony fixed the problem by making the sled out of die-cast metal and placing the laser unit further away from the power supply on later PlayStation models. Due to an engineering oversight, the PlayStation does not produce a proper signal on several older models of televisions, causing the display to flicker or bounce around the screen. Sony decided not to change the console design, since only a small percentage of PlayStation owners used such televisions, and instead gave consumers the option of sending their PlayStation unit to a Sony service centre to have an official modchip installed, allowing play on older televisions. Game library The PlayStation featured a diverse game library which grew to appeal to all types of players. Critically acclaimed PlayStation games included Final Fantasy VII (1997), Crash Bandicoot (1996), Spyro the Dragon (1998), Metal Gear Solid (1998), all of which became established franchises. Final Fantasy VII is credited with allowing role-playing games to gain mass-market appeal outside Japan, and is considered one of the most influential and greatest video games ever made. The PlayStation's bestselling game is Gran Turismo (1997), which sold 10.85 million units. After the PlayStation's discontinuation in 2006, the cumulative software shipment was 962 million units. Following its 1994 launch in Japan, early games included Ridge Racer, Crime Crackers, King's Field, Motor Toon Grand Prix, Toh Shin Den (i.e. Battle Arena Toshinden), and Kileak: The Blood. The first two games available at its later North American launch were Jumping Flash! (1995) and Ridge Racer, with Jumping Flash! heralded as an ancestor for 3D graphics in console gaming. Wipeout, Air Combat, Twisted Metal, Warhawk and Destruction Derby were among the popular first-year games, and the first to be reissued as part of Sony's Greatest Hits or Platinum range. At the time of the PlayStation's first Christmas season, Psygnosis had produced around 70% of its launch catalogue; their breakthrough racing game Wipeout was acclaimed for its techno soundtrack and helped raise awareness of Britain's underground music community. Eidos Interactive's action-adventure game Tomb Raider contributed substantially to the success of the console in 1996, with its main protagonist Lara Croft becoming an early gaming icon and garnering unprecedented media promotion. Licensed tie-in video games of popular films were also prevalent; Argonaut Games' 2001 adaptation of Harry Potter and the Philosopher's Stone went on to sell over eight million copies late in the console's lifespan. Third-party developers committed largely to the console's wide-ranging game catalogue even after the launch of the PlayStation 2; some of the notable exclusives in this era include Harry Potter and the Philosopher's Stone, Fear Effect 2: Retro Helix, Syphon Filter 3, C-12: Final Resistance, Dance Dance Revolution Konamix and Digimon World 3.[c] Sony assisted with game reprints as late as 2008 with Metal Gear Solid: The Essential Collection, this being the last PlayStation game officially released and licensed by Sony. Initially, in the United States, PlayStation games were packaged in long cardboard boxes, similar to non-Japanese 3DO and Saturn games. Sony later switched to the jewel case format typically used for audio CDs and Japanese video games, as this format took up less retailer shelf space (which was at a premium due to the large number of PlayStation games being released), and focus testing showed that most consumers preferred this format. Reception The PlayStation was mostly well received upon release. Critics in the west generally welcomed the new console; the staff of Next Generation reviewed the PlayStation a few weeks after its North American launch, where they commented that, while the CPU is "fairly average", the supplementary custom hardware, such as the GPU and sound processor, is stunningly powerful. They praised the PlayStation's focus on 3D, and complemented the comfort of its controller and the convenience of its memory cards. Giving the system 41⁄2 out of 5 stars, they concluded, "To succeed in this extremely cut-throat market, you need a combination of great hardware, great games, and great marketing. Whether by skill, luck, or just deep pockets, Sony has scored three out of three in the first salvo of this war." Albert Kim from Entertainment Weekly praised the PlayStation as a technological marvel, rivalling that of Sega and Nintendo. Famicom Tsūshin scored the console a 19 out of 40, lower than the Saturn's 24 out of 40, in May 1995. In a 1997 year-end review, a team of five Electronic Gaming Monthly editors gave the PlayStation scores of 9.5, 8.5, 9.0, 9.0, and 9.5—for all five editors, the highest score they gave to any of the five consoles reviewed in the issue. They lauded the breadth and quality of the games library, saying it had vastly improved over previous years due to developers mastering the system's capabilities in addition to Sony revising their stance on 2D and role playing games. They also complimented the low price point of the games compared to the Nintendo 64's, and noted that it was the only console on the market that could be relied upon to deliver a solid stream of games for the coming year, primarily due to third party developers almost unanimously favouring it over its competitors. Legacy SCE was an upstart in the video game industry in late 1994, as the video game market in the early 1990s was dominated by Nintendo and Sega. Nintendo had been the clear leader in the industry since the introduction of the Nintendo Entertainment System in 1985 and the Nintendo 64 was initially expected to maintain this position. The PlayStation's target audience included the generation which was the first to grow up with mainstream video games, along with 18- to 29-year-olds who were not the primary focus of Nintendo. By the late 1990s, Sony became a highly regarded console brand due to the PlayStation, with a significant lead over second-place Nintendo, while Sega was relegated to a distant third. The PlayStation became the first "computer entertainment platform" to ship over 100 million units worldwide, with many critics attributing the console's success to third-party developers. It remains the sixth best-selling console of all time as of 2025[update], with a total of 102.49 million units sold. Around 7,900 individual games were published for the console during its 11-year life span, the second-most games ever produced for a console. Its success resulted in a significant financial boon for Sony as profits from their video game division contributed to 23%. Sony's next-generation PlayStation 2, which is backward compatible with the PlayStation's DualShock controller and games, was announced in 1999 and launched in 2000. The PlayStation's lead in installed base and developer support paved the way for the success of its successor, which overcame the earlier launch of the Sega's Dreamcast and then fended off competition from Microsoft's newcomer Xbox and Nintendo's GameCube. The PlayStation 2's immense success and failure of the Dreamcast were among the main factors which led to Sega abandoning the console market. To date, five PlayStation home consoles have been released, which have continued the same numbering scheme, as well as two portable systems. The PlayStation 3 also maintained backward compatibility with original PlayStation discs. Hundreds of PlayStation games have been digitally re-released on the PlayStation Portable, PlayStation 3, PlayStation Vita, PlayStation 4, and PlayStation 5. The PlayStation has often ranked among the best video game consoles. In 2018, Retro Gamer named it the third best console, crediting its sophisticated 3D capabilities as one of its key factors in gaining mass success, and lauding it as a "game-changer in every sense possible". In 2009, IGN ranked the PlayStation the seventh best console in their list, noting its appeal towards older audiences to be a crucial factor in propelling the video game industry, as well as its assistance in transitioning game industry to use the CD-ROM format. Keith Stuart from The Guardian likewise named it as the seventh best console in 2020, declaring that its success was so profound it "ruled the 1990s". In January 2025, Lorentio Brodesco announced the nsOne project, attempting to reverse engineer PlayStation's motherboard. Brodesco stated that "detailed documentation on the original motherboard was either incomplete or entirely unavailable". The project was successfully crowdfunded via Kickstarter. In June, Brodesco manufactured the first working motherboard, promising to bring a fully rooted version with multilayer routing as well as documentation and design files in the near future. The success of the PlayStation contributed to the demise of cartridge-based home consoles. While not the first system to use an optical disc format, it was the first highly successful one, and ended up going head-to-head with the proprietary cartridge-relying Nintendo 64,[d] which the industry had expected to use CDs like PlayStation. After the demise of the Sega Saturn, Nintendo was left as Sony's main competitor in Western markets. Nintendo chose not to use CDs for the Nintendo 64; they were likely concerned with the proprietary cartridge format's ability to help enforce copy protection, given their substantial reliance on licensing and exclusive games for their revenue. Besides their larger capacity, CD-ROMs could be produced in bulk quantities at a much faster rate than ROM cartridges, a week compared to two to three months. Further, the cost of production per unit was far cheaper, allowing Sony to offer games about 40% lower cost to the user compared to ROM cartridges while still making the same amount of net revenue. In Japan, Sony published fewer copies of a wide variety of games for the PlayStation as a risk-limiting step, a model that had been used by Sony Music for CD audio discs. The production flexibility of CD-ROMs meant that Sony could produce larger volumes of popular games to get onto the market quickly, something that could not be done with cartridges due to their manufacturing lead time. The lower production costs of CD-ROMs also allowed publishers an additional source of profit: budget-priced reissues of games which had already recouped their development costs. Tokunaka remarked in 1996: Choosing CD-ROM is one of the most important decisions that we made. As I'm sure you understand, PlayStation could just as easily have worked with masked ROM [cartridges]. The 3D engine and everything—the whole PlayStation format—is independent of the media. But for various reasons (including the economies for the consumer, the ease of the manufacturing, inventory control for the trade, and also the software publishers) we deduced that CD-ROM would be the best media for PlayStation. The increasing complexity of developing games pushed cartridges to their storage limits and gradually discouraged some third-party developers. Part of the CD format's appeal to publishers was that they could be produced at a significantly lower cost and offered more production flexibility to meet demand. As a result, some third-party developers switched to the PlayStation, including Square and Enix, whose Final Fantasy VII and Dragon Quest VII respectively had been planned for the Nintendo 64 (both companies later merged to form Square Enix). Other developers released fewer games for the Nintendo 64 (Konami, releasing only thirteen N64 games but over fifty on the PlayStation). Nintendo 64 game releases were less frequent than the PlayStation's, with many being developed by either Nintendo themselves or second-parties such as Rare. The PlayStation Classic is a dedicated video game console made by Sony Interactive Entertainment that emulates PlayStation games. It was announced in September 2018 at the Tokyo Game Show, and released on 3 December 2018, the 24th anniversary of the release of the original console. As a dedicated console, the PlayStation Classic features 20 pre-installed games; the games run off the open source emulator PCSX. The console is bundled with two replica wired PlayStation controllers (those without analogue sticks), an HDMI cable, and a USB-Type A cable. Internally, the console uses a MediaTek MT8167a Quad A35 system on a chip with four central processing cores clocked at @ 1.5 GHz and a Power VR GE8300 graphics processing unit. It includes 16 GB of eMMC flash storage and 1 Gigabyte of DDR3 SDRAM. The PlayStation Classic is 45% smaller than the original console. The PlayStation Classic received negative reviews from critics and was compared unfavorably to Nintendo's rival Nintendo Entertainment System Classic Edition and Super Nintendo Entertainment System Classic Edition. Criticism was directed at its meagre game library, user interface, emulation quality, use of PAL versions for certain games, use of the original controller, and high retail price, though the console's design received praise. The console sold poorly. See also Notes References |
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[SOURCE: https://en.wikipedia.org/wiki/Satyr] | [TOKENS: 8995] |
Contents Satyr In Greek mythology, a satyr[a] (Ancient Greek: σάτυρος, romanized: sátyros, pronounced [sátyros]), also known as a silenus[b] or silenos (Ancient Greek: σειληνός, romanized: seilēnós [seːlɛːnós]), and sileni (plural), is a male nature spirit with ears and a tail resembling those of a horse, as well as a permanent, exaggerated erection. Early artistic representations sometimes include horse-like legs, but, by the sixth century BC, they were more often represented with human legs. Comically hideous, they have mane-like hair, bestial faces, and snub noses and they always are shown naked. Satyrs were characterized by their ribaldry and were known as lovers of wine, music, dancing, and women. They were companions of the god Dionysus and were believed to inhabit remote locales, such as woodlands, mountains, and pastures. They often attempted to seduce or rape nymphs and mortal women alike, usually with little success. They are sometimes shown masturbating or engaging in bestiality. In classical Athens, satyrs made up the chorus in a genre of play known as a "satyr play", which was a parody of tragedy and known for its bawdy and obscene humor. The only complete surviving play of this genre is Cyclops by Euripides, although a significant portion of Sophocles's Ichneutae has also survived. In mythology, the satyr Marsyas is said to have challenged the god Apollo to a musical contest and been flayed alive for his hubris. Although superficially ridiculous, satyrs were also thought to possess useful knowledge, if they could be coaxed into revealing it. The satyr Silenus was the tutor of the young Dionysus, and a story from Ionia told of a silenos who gave sound advice when captured. Over the course of Greek history, satyrs gradually became portrayed as more human and less bestial. They also began to acquire goat-like characteristics in some depictions as a result of conflation with the Pans, plural forms of the god Pan with the legs and horns of goats. The Romans identified satyrs with their native nature spirits, fauns. Eventually the distinction between the two was lost entirely. Since the Renaissance, satyrs have been most often represented with the legs and horns of goats. Representations of satyrs cavorting with nymphs have been common in western art, with many famous artists creating works on the theme. Since the beginning of the twentieth century, satyrs have generally lost much of their characteristic obscenity, becoming more tame and domestic figures. They commonly appear in works of fantasy and children's literature, in which they are most often referred to as "fauns". Terminology The etymology of the term satyr (Ancient Greek: σάτυρος, romanized: sátyros) is unclear, and several different etymologies have been proposed for it, including a possible Pre-Greek origin. Some scholars have linked the second part of name to the root of the Greek word θηρίον, thēríon, meaning 'wild animal'. This proposal may be supported by the fact that at one point Euripides refers to satyrs as theres. Another proposed etymology derives the name from an ancient Peloponnesian word meaning 'the full ones', alluding to their permanent state of sexual arousal. Eric Partridge suggested that the name may be related to the root sat-, meaning 'to sow', which has also been proposed as the root of the name of the Roman god Saturn. Satyrs are usually indistinguishable from sileni, whose iconography is virtually identical. According to Brewer's Dictionary of Phrase and Fable, the name 'satyr' is sometimes derogatorily applied to a "brutish or lustful man". The term satyriasis refers to a medical condition in males characterized by excessive sexual desire. It is the male equivalent of nymphomania. Origin hypotheses According to classicist Martin Litchfield West, satyrs and silenoi in Greek mythology are similar to a number of other entities appearing in other Indo-European mythologies, indicating that they probably go back, in some vague form, to Proto-Indo-European mythology. Like satyrs, these other Indo-European nature spirits are often human-animal hybrids, frequently bearing specifically equine or asinine features. Human-animal hybrids known as Kiṃpuruṣas or Kiṃnaras are mentioned in the Rāmāyaṇa, an Indian epic poem written in Sanskrit. According to Augustine of Hippo (354–430 AD) and others, the ancient Celts believed in dusii, which were hairy demons believed to occasionally take human form and seduce mortal women. Later figures in Celtic folklore, including the Irish bocánach, the Scottish ùruisg and glaistig, and the Manx goayr heddagh, are part human and part goat. The lexicographer Hesychius of Alexandria (fifth or sixth century AD) records that the Illyrians believed in satyr-like creatures called Deuadai. The Slavic leshy also bears similarities to satyrs, since he is described as being covered in hair and having "goat's horns, ears, feet, and long clawlike fingernails." Like satyrs, these similar creatures in other Indo-European mythologies are often also tricksters, mischief-makers, and dancers. The leshy was believed to trick travelers into losing their way. The Armenian Pay(n) were a group of male spirits said to dance in the woods. In Germanic mythology, elves were also said to dance in woodland clearings and leave behind fairy rings. They were also thought to play pranks, steal horses, tie knots in people's hair, and steal children and replace them with changelings. West notes that satyrs, elves, and other nature spirits of this variety are a "motley crew" and that it is difficult to reconstruct a prototype behind them. Nonetheless, he concludes that "we can recognize recurrent traits" and that they can probably be traced back to the Proto-Indo-Europeans in some form. On the other hand, a number of commentators have noted that satyrs are also similar to beings in the beliefs of ancient Near Eastern cultures. Various demons of the desert are mentioned in ancient Near Eastern texts, although the iconography of these beings is poorly-attested. Beings possibly similar to satyrs called śě'îrîm are mentioned several times in the Hebrew Bible. Śĕ'îr was the standard Hebrew word for 'he-goat', but it could also apparently sometimes refer to demons in the forms of goats. They were evidently subjects of veneration, because Leviticus 17:7 forbids Israelites from making sacrificial offerings to them and 2 Chronicles 11:15 mentions that a special cult was established for the śě'îrîm of Jeroboam I. Like satyrs, they were associated with desolate places and with some variety of dancing. Isaiah 13:21 predicts, in Karen L. Edwards's translation: "But wild animals [ziim] will lie down there, and its houses will be full of howling creatures [ohim]; there ostriches will live, and there goat-demons [śĕ'îr] will dance." Similarly, Isaiah 34:14 declares: "Wildcats [ziim] shall meet with hyenas [iim], goat-demons [śĕ'îr] shall call to each other; there too Lilith [lilit] shall repose and find a place to rest." Śě'îrîm were understood by at least some ancient commentators to be goat-like demons of the wilderness. In the Latin Vulgate translation of the Old Testament, śĕ'îr is translated as pilosus, which also means 'hairy'. Jerome, the translator of the Vulgate, equated these figures with satyrs. Both satyrs and śě'îrîm have also been compared to the jinn of Pre-Islamic Arabia, who were envisioned as hairy demons in the forms of animals who could sometimes change into other forms, including human-like ones. In archaic and classical Greece In archaic and classical Greek art, satyrs are shown with the ears and tails of horses. They walk upright on two legs, like human beings. They are usually shown with bestial faces, snub noses, and manelike hair. They are often bearded and balding. Like other Greek nature spirits, satyrs are always depicted nude. Sometimes they also have the legs of horses, but, in ancient art, including both vase paintings and in sculptures, satyrs are most often represented with human legs and feet. Satyrs' genitals are always depicted as either erect or at least extremely large. Their erect phalli represent their association with wine and women, which were the two major aspects of their god Dionysus's domain. In some cases, satyrs are portrayed as very human-like, lacking manes or tails. As time progressed, this became the general trend, with satyrs losing aspects of their original bestial appearance over the course of Greek history and gradually becoming more and more human. In the most common depictions, satyrs are shown drinking wine, dancing, playing flutes, chasing nymphs, or consorting with Dionysus. They are also frequently shown masturbating or copulating with animals. In scenes from ceramic paintings depicting satyrs engaging in orgies, satyrs standing by and watching are often shown masturbating. One of the earliest written sources for satyrs is the Catalogue of Women, which is attributed to the Boeotian poet Hesiod. Here satyrs are born alongside the nymphs and Kouretes and are described as "good-for-nothing, prankster Satyrs". Satyrs were widely seen as mischief-makers who routinely played tricks on people and interfered with their personal property. They had insatiable sexual appetites and often sought to seduce or ravish both nymphs and mortal women alike, though these attempts were not always successful. Satyrs almost always appear in artwork alongside female companions of some variety. These female companions may be clothed or nude, but the satyrs always treat them as mere sexual objects. A single elderly satyr named Silenus was believed to have been the tutor of Dionysus on Mount Nysa. After Dionysus grew to maturity, Silenus became one of his most devout followers, remaining perpetually drunk. This image was reflected in the classical Athenian satyr play. Satyr plays were a genre of plays defined by the fact that their choruses were invariably made up of satyrs. These satyrs are always led by Silenus, who is their "father". According to Carl A. Shaw, the chorus of satyrs in a satyr play were "always trying to get a laugh with their animalistic, playfully rowdy, and, above all, sexual behavior." The satyrs play an important role in driving the plot of the production, without any of them actually being the lead role, which was always reserved for a god or tragic hero. Many satyr plays are named for the activity in which the chorus of satyrs engage during the production, such as Δικτυουλκοί, Diktyoulkoí, 'Net-Haulers', Θεωροὶ ἢ Ἰσθμιασταί, Theōroì ē Isthmiastaí, 'Spectators or Competitors at the Isthmian Games', and Ἰχνευταί, Ichneutaí, 'Searchers'. Like tragedies, but unlike comedies, satyr plays were set in the distant past and dealt with mythological subjects. The third or second-century BC philosopher Demetrius of Phalerum famously characterized the satiric genre in his treatise De Elocutione as the middle ground between tragedy and comedy: a "playful tragedy" (τραγῳδία παίζουσα, tragōdía paízdousa). The only complete extant satyr play is Euripides's Cyclops, which is a burlesque of a scene from the eighth-century BC epic poem, the Odyssey, in which Odysseus is captured by the Cyclops Polyphemus in a cave. In the play, Polyphemus has captured a tribe of satyrs led by Silenus, who is described as their "Father", and forced them to work for him as his slaves. After Polyphemus captures Odysseus, Silenus attempts to play Odysseus and Polyphemus off each other for his own benefit, primarily by tricking them into giving him wine. As in the original scene, Odysseus manages to blind Polyphemus and escape. Approximately 450 lines, most of which are fragmentary, have survived of Sophocles's satyr play Ichneutae (Tracking Satyrs). In the surviving portion of the play, the chorus of satyrs are described as "lying on the ground like hedgehogs in a bush, or like a monkey bending over to fart at someone." The character Cyllene scolds them: "All you [satyrs] do you do for the sake of fun!... Cease to expand your smooth phallus with delight. You should not make silly jokes and chatter, so that the gods will make you shed tears to make me laugh." In Dionysius I of Syracuse's fragmentary satyr play Limos (Starvation), Silenus attempts to give the hero Heracles an enema. A number of vase paintings depict scenes from satyr plays, including the Pronomos Vase, which depicts the entire cast of a victorious satyr play, dressed in costume, wearing shaggy leggings, erect phalli, and horse tails. The genre's reputation for crude humor is alluded to in other texts as well. In Aristophanes's comedy Thesmophoriazusae, the tragic poet Agathon declares that a dramatist must be able to adopt the personae of his characters in order to successfully portray them on stage. In lines 157–158, Euripides's unnamed relative retorts: "Well, let me know when you're writing satyr plays; I'll get behind you with my hard-on and show you how." This is the only extant reference to the genre of satyr plays from a work of ancient Greek comedy and, according to Shaw, it effectively characterizes satyr plays as "a genre of 'hard-ons.'" In spite of their bawdy behavior, however, satyrs were still revered as semi-divine beings and companions of the god Dionysus. They were thought to possess their own kind of wisdom that was useful to humans if they could be convinced to share it. In Plato's Symposium, Alcibiades praises Socrates by comparing him to the famous satyr Marsyas. He resembles him physically, since he is balding and has a snub-nose, but Alcibiades contends that he resembles him mentally as well, because he is "insulting and abusive", in possession of irresistible charm, "erotically inclined to beautiful people", and "acts as if he knows nothing". Alcibiades concludes that Socrates's role as a philosopher is similar to that of the paternal satyr Silenus, because, at first, his questions seem ridiculous and laughable, but, upon closer inspection, they are revealed to be filled with much wisdom. One story, mentioned by Herodotus in his Histories and in a fragment by Aristotle, recounts that King Midas once captured a silenus, who provided him with wise philosophical advice. According to classicist William Hansen, although satyrs were popular in classical art, they rarely appear in surviving mythological accounts. Different classical sources present conflicting accounts of satyrs' origins. According to a fragment from the Hesiodic Catalogue of Women, satyrs are sons of the five granddaughters of Phoroneus and therefore siblings of the Oreads and the Kouretes. The satyr Marsyas, however, is described by mythographers as the son of either Olympos or Oiagros. Hansen observes that "there may be more than one way to produce a satyr, as there is to produce a Cyclops or a centaur." The classical Greeks recognized that satyrs obviously could not self-reproduce since there were no female satyrs, but they seem to have been unsure whether satyrs were mortal or immortal. Rather than appearing en masse as in satyr-plays, when satyrs appear in myths it is usually in the form of a single, famous character. The comic playwright Melanippides of Melos (c. 480–430 BC) tells the story in his lost comedy Marsyas of how, after inventing the aulos, the goddess Athena looked in the mirror while she was playing it. She saw how blowing into it puffed up her cheeks and made her look silly, so she threw the aulos away and cursed it so that whoever picked it up would meet an awful death. The aulos was picked up by the satyr Marsyas, who challenged Apollo to a musical contest. They both agreed beforehand that whoever won would be allowed to do whatever he wanted to the loser. Marsyas played the aulos and Apollo played the lyre. Apollo turned his lyre upside-down and played it. He asked Marsyas to do the same with his instrument. Since he could not, Apollo was deemed to victor. Apollo hung Marsyas from a pine tree and flayed him alive to punish him for his hubris in daring to challenge one of the gods. Later, this story became accepted as canonical and the Athenian sculptor Myron created a group of bronze sculptures based on it, which was installed before the western front of the Parthenon in around 440 BC. Surviving retellings of the legend are found in the Library of Pseudo-Apollodorus, Pausanias's Guide to Greece, and the Fabulae of Pseudo-Hyginus. In a myth referenced in multiple classical texts, including the Bibliotheke of Pseudo-Apollodorus and the Fabulae of Pseudo-Hyginus, a satyr from Argos once attempted to rape the nymph Amymone, but she called to the god Poseidon for help and he launched his trident at the satyr, knocking him to the ground. This myth may have originated from Aeschylus's lost satyr play Amymone. Scenes of one or more satyrs chasing Amymone became a common trope in Greek vase paintings starting in the late fifth century BC. One of the earliest depictions of the scene comes from a bell krater in the style of the Peleus Painter from Syracuse (PEM 10, pl. 155) and another from a bell krater in the style of the Dinos Painter from Vienna (DM 7). According to one account, Satyrus was one of the many sons of Dionysus and the Bithynian nymph Nicaea, born after Dionysus tricked Nicaea into getting drunk and raped her as she lay unconscious. Fasti Many names of the satyrs that appear in Nonnos' Dionysiaca are heavily assumed to have been coined by the author, and are nothing more than plot devices with no mythological significance. Four names listed in the epic, when translated, are merely adjectives associated to the character ("Pastoral", "Cult-association", "Tall-horn", and "Mountain-dweller"). The names of the satyrs according to various vase paintings were: Babacchos, Briacchos, Dithyrambos, Demon, Dromis, Echon, Hedyoinos ("Sweet Wine"), Hybris ("Insolence"), Hedymeles, ("Sweet Song"), Komos ("Revelry"), Kissos ("Ivy"), Molkos, Oinos, Oreimachos, Simos ("Snub-nose"), Terpon and Tyrbas ("Rout"). Later antiquity The iconography of satyrs was gradually conflated with that of the Pans, plural forms of the god Pan, who were regularly depicted with the legs and horns of a goat. By the Hellenistic Period (323–31 BC), satyrs were beginning to sometimes be shown with goat-like features. Meanwhile, both satyrs and Pans also continued to be shown as more human and less bestial. Scenes of satyrs and centaurs were very popular during the Hellenistic Period. They often appear dancing or playing the aulos. The maenads that often accompany satyrs in Archaic and Classical representations are often replaced in Hellenistic portrayals with wood nymphs. Artists also began to widely represent scenes of nymphs repelling the unwanted advances of amorous satyrs. Scenes of this variety were used to express the dark, beastly side of human sexuality at a remove by attributing that sexuality to satyrs, who were part human and part animal. In this way, satyrs became vehicles of a metaphor for a phenomenon extending far beyond the original narrative purposes in which they had served during earlier periods of Greek history. Some variants on this theme represent a satyr being rebuffed by a hermaphrodite, who, from the satyr's perspective, appears to be a beautiful, young girl. These sculptures may have been intended as kind of sophisticated erotic joke. The Athenian sculptor Praxiteles's statue Pouring Satyr represented the eponymous satyr as very human-like. The satyr was shown as very young, in line with Praxiteles's frequent agenda of representing deities and other figures as adolescents. This tendency is also attested in the descriptions of his sculptures of Dionysus and the Archer Eros written in the third or fourth century AD by the art critic Callistratus. The original statue is widely assumed to have depicted the satyr in the act of pouring an oinochoe over his head into a cup, probably a kantharos. Antonio Corso describes the satyr in this sculpture as a "gentle youth" and "a precious and gentle being" with "soft and velvety" skin. The only hints at his "feral nature" were his ears, which were slightly pointed, and his small tail. The shape of the sculpture was an S-shape, shown in three-quarter view. The satyr had short, boyish locks, derived from those of earlier Greek athletic sculpture. Although the original statue has been lost, a representation of the pouring satyr appears in a late classical relief sculpture from Athens and twenty-nine alleged "copies" of the statue from the time of the Roman Empire have also survived. Olga Palagia and J. J. Pollitt argue that, although the Pouring Satyr is widely accepted as a genuine work of Praxiteles, it may not have been a single work at all and the supposed "copies" of it may merely be Roman sculptures repeating the traditional Greek motif of pouring wine at symposia. The Romans identified satyrs with their own nature spirits, fauns. Although generally similar to satyrs, fauns differed in that they were usually seen as "shy, woodland creatures" rather than the drunk and boisterous satyrs of the classical Greeks. Also, fauns generally lacked the association Greek satyrs had with secret wisdom. Unlike classical Greek satyrs, fauns were unambiguously goat-like; they had the upper bodies of men, but the legs, hooves, tail, and horns of goats. The first-century BC Roman poet Lucretius mentions in his lengthy poem De rerum natura that people of his time believed in "goat-legged" (capripedes) satyrs, along with nymphs who lived in the mountains and fauns who played rustic music on stringed instruments and pipes. In Roman-era depictions, satyrs and fauns are both often associated with music and depicted playing the Pan pipes or syrinx. The poet Virgil, who flourished during the early years of the Roman Empire, recounts a story in his sixth Eclogue about two boys who tied up the satyr Silenus while he was in a drunken stupor and forced him to sing them a song about the beginning of the universe. The first-century AD Roman poet Ovid makes Jupiter, the king of the gods, express worry that the viciousness of humans will leave fauns, nymphs, and satyrs without a place to live, so he gives them a home in the forests, woodlands, and mountains, where they will be safe. Ovid also retells the story of Marsyas's hubris. He describes a musical contest between Marsyas, playing the aulos, and the god Apollo, playing the lyre. Marsyas loses and Apollo flays him as punishment. The Roman naturalist and encyclopedist Pliny the Elder conflated satyrs with gibbons, which he describes using the word satyrus, a Latinized form of the Greek satyros. He characterizes them as "a savage and wild people; distinct voice and speech they have none, but in steed thereof, they keep a horrible gnashing and hideous noise: rough they are and hairie all over their bodies, eies they have red like the houlets [owls] and toothed they be like dogs." The second-century Greek Middle Platonist philosopher Plutarch records a legendary incident in his Life of Sulla, in which the soldiers of the Roman general Sulla are reported to have captured a satyr sleeping during a military campaign in Greece in 89 BC. Sulla's men brought the satyr to him and he attempted to interrogate it, but it spoke only in an unintelligible sound: a cross between the neighing of a horse and the bleating of a goat. The second-century Greek travel writer Pausanias reports having seen the tombs of deceased silenoi in Judaea and at Pergamon. Based on these sites, Pausanias concludes that silenoi must be mortal. The third-century Greek biographer Philostratus records a legend in his Life of Apollonius of Tyana of how the ghost of an Aethiopian satyr was deeply enamored with the women from the local village and had killed two of them. Then, the philosopher Apollonius of Tyana set a trap for it with wine, knowing that, after drinking it, the ghost-satyr would fall asleep forever. The wine diminished from the container before the onlookers' eyes, but the ghost-satyr himself remained invisible. Once all the wine had vanished, the ghost-satyr fell asleep and never bothered the villagers again. Amira El-Zein notes similarities between this story and later Arabic accounts of jinn. The treatise Saturnalia by the fifth-century AD Roman poet Macrobius connects both the word satyr and the name Saturn to the Greek word for "penis". Macrobius explains that this is on account of satyrs' sexual lewdness. Macrobius also equates Dionysus and Apollo as the same deity and states that a festival in honor of Bacchus is held every year atop Mount Parnassus, at which many satyrs are often seen. After antiquity Starting in late antiquity, Christian writers began to portray satyrs and fauns as dark, evil, and demonic. Jerome (c. 347 – 420 AD) described them as symbols of Satan on account of their lasciviousness. Despite this, however, satyrs were sometimes clearly distinguished from demons and sometimes even portrayed as noble. Because Christians believed that the distinction between humans and animals was spiritual rather than physical, it was thought that even a satyr could attain salvation. Isidore of Seville (c. 560 – 636) records an anecdote later recounted in the Golden Legend, that Anthony the Great encountered a satyr in the desert who asked to pray with him to their common God. During the Early Middle Ages, features and characteristics of satyrs and the god Pan, who resembled a satyr, became absorbed into traditional Christian iconography of Satan. Medieval storytellers in Western Europe also frequently conflated satyrs with wild men. Both satyrs and wild men were conceived as part human and part animal and both were believed to possess unrestrained sexual appetites. Stories of wild men during the Middle Ages often had an erotic tone and were primarily told orally by peasants, since the clergy officially disapproved of them. In this form, satyrs are sometimes described and represented in medieval bestiaries, where a satyr is often shown dressed in an animal skin, carrying a club and a serpent. In the Aberdeen Bestiary, the Ashmole Bestiary, and MS Harley 3244, a satyr is shown as a nude man holding a wand resembling a jester's club and leaning back, crossing his legs. Satyrs are sometimes juxtaposed with apes, which are characterized as "physically disgusting and akin to the Devil". In other cases, satyrs are usually shown nude, with enlarged phalli to emphasize their sexual nature. In the Second-Family Bestiary, the name "satyr" is used as the name of a species of ape, which is described as having a "very agreeable face, restless, however, in its twitching movements." During the Renaissance, satyrs and fauns began to reappear in works of European art. During the Renaissance, no distinction was made between satyrs and fauns and both were usually given human and goat-like features in whatever proportion the artist deemed appropriate. A goat-legged satyr appears at the base of Michelangelo's statue Bacchus (1497). Renaissance satyrs still sometimes appear in scenes of drunken revelry like those from antiquity, but they also sometimes appear in family scenes, alongside female and infant or child satyrs. This trend towards more familial, domestic satyrs may have resulted from conflation with wild men, who, especially in Renaissance depictions from Germany, were often portrayed as living relatively peaceful lives with their families in the wilderness. The most famous representation of a domestic satyr is Albrecht Dürer's 1505 engraving The Satyr's Family, which has been widely reproduced and imitated. This popular portrayal of satyrs and wild men may have also helped give rise to the later European concept of the noble savage. Satyrs occupied a paradoxical, liminal space in Renaissance art, not only because they were part human and part beast, but also because they were both antique and natural. They were of classical origin, but had an iconographical canon of their own very different from the standard representations of gods and heroes. They could be used to embody what Stephen J. Campbell calls a "monstrous double" of the category in which human beings often placed themselves. It is in this aspect that satyrs appear in Jacopo de' Barbari's c. 1495 series of prints depicting satyrs and naked men in combat and in Piero di Cosimo's Stories of Primitive Man, inspired by Lucretius. Satyrs became seen as "pre-human", embodying all the traits of savagery and barbarism associated with animals, but in human-like bodies. Satyrs also became used to question early modern humanism in ways which some scholars have seen as similar to present-day posthumanism, as in Titian's Flaying of Marsyas (c. 1570–1576). The Flaying of Marysas depicts the scene from Ovid's Metamorphoses in which the satyr Marysas is flayed alive. According to Campbell, the people performing the flaying are shown calmly absorbed in their task, while Marsyas himself even displays "an unlikely patience". The painting reflects a broad continuum between the divine and the bestial. In the 1560 Geneva Bible, the word sa'ir in both of the instances in Isaiah is translated into English as 'satyr'. The 1611 King James Version follows this translation and likewise renders sa'ir as 'satyr'. Edwards states that the King James Version's translation of this phrase and others like it was intended to reduce the strangeness and unfamiliarity of the creatures described in the original Hebrew text by rendering them as names of familiar entities. Edmund Spenser refers to a group of woodland creatures as Satyrs in his epic poem The Faerie Queene. In Canto VI, Una is wandering through the forest when she stumbles upon a "troupe of Fauns and Satyrs far away Within the wood were dancing in a round." Although Satyrs are often negatively characterized in Greek and Roman mythology, the Satyrs in this poem are docile, helpful creatures. This is evident by the way they help protect Una from Sansloy. Sylvanus, the leader, and the rest of the Satyrs become enamored by Una's beauty and begin to worship her as if she is a deity. However, the Satyrs prove to be simple-minded creatures because they begin to worship the donkey she was riding.[citation needed] In the seventeenth century, satyrs became identified with great apes. In 1699, the English anatomist Edward Tyson (1651–1708) published an account of his dissection of a creature which scholars have now identified as chimpanzee. In this account, Tyson argued that stories of satyrs, wild men, and other hybrid mythological creatures had all originated from the misidentification of apes or monkeys. The French materialist philosopher Julien Offray de La Mettrie (1709–1751) included a section titled "On savage men, called Satyrs" in his Oeuvres philosophiques, in which he describes great apes, identifying them with both satyrs and wild men. Many early accounts of the orangutan describe the males as being sexually aggressive towards human women and towards females of its own species, much like classical Greek satyrs. The first scientific name given to this ape was Simia satyrus. Relationships between satyrs and nymphs of this period are often portrayed as consensual. This trend is exemplified by the 1623 painting Satyr and Nymph by Gerard van Honthorst, which depicts a satisfied satyr and nymph lasciviously fondling each other after engaging in obviously consensual sex. Both are smiling and the nymph is showing her teeth, a sign commonly used by painters of the era to signify that the woman in question is of loose morals. The satyr's tongue is visible as the nymph playfully tugs on his goat beard and he strokes her chin. Even during this period, however, depictions of satyrs uncovering sleeping nymphs are still common, indicating that their traditional associations with rape and sexual violence had not been forgotten. During the nineteenth century, satyrs and nymphs came to often function as a means of representing sexuality without offending Victorian moral sensibilities. In the novel The Marble Faun (1860) by the American author Nathaniel Hawthorne, the Italian count Donatello is described as bearing a remarkable resemblance to one of Praxiteles's marble satyr statues. Like the satyrs of Greek legend, Donatello has a carefree nature. His association with satyrs is further cemented by his intense sexual attraction to the American woman Miriam. Satyrs and nymphs provided a classical pretext which allowed sexual depictions of them to be seen as objects of high art rather than mere pornography. The French emperor Napoleon III awarded the Academic painter Alexandre Cabanel the Legion of Honour, partly on account of his painting Nymph Abducted by a Faun. In 1873, another French Academicist William-Adolphe Bouguereau painted Nymphs and Satyr, which depicts four nude nymphs dancing around "an unusually submissive satyr", gently coaxing him into the water of a nearby stream. This painting was bought that same year by an American named John Wolfe, who displayed it publicly in a prominent location in the bar at the Hoffman House, a hotel he owned on Madison Square and Broadway. Despite its risqué subject, many women came to the bar to view the painting. The painting was soon mass reproduced on ceramic tiles, porcelain plates, and other luxury items in the United States. In 1876, Stéphane Mallarmé wrote "The Afternoon of a Faun", a first-person narrative poem about a faun who attempts to kiss two beautiful nymphs while they are sleeping together. He accidentally wakes them up. Startled, they transform into white water birds and fly away, leaving the faun to play his pan pipes alone. Claude Debussy composed a symphonic poem Prélude à l'après-midi d'un faune (Prelude to the Afternoon of a Faun), which was first performed in 1894. The late nineteenth-century German Existentialist philosopher Friedrich Nietzsche was either unaware of or chose to ignore the fact that, in all the earliest representations, satyrs are depicted as horse-like. He accordingly defined a satyr as a "bearded" creature "who derived his name and attributes from the goat." Nietzsche excluded the horse-like satyrs of Greek tradition from his consideration entirely and argued that tragedy had originated from a chorus of men dressed up as satyrs or goats (tragoi). Thus, Nietzsche held that tragedy had begun as a Dionysian activity. Nietzsche's rejection of the early evidence for horse-like satyrs was a mistake his critics severely excoriated him for. Nonetheless, he was the first modern scholar to recognize the full importance of satyrs in Greek culture and tradition, as Dionysian symbols of humanity's close ties to the animal kingdom. Like the Greeks, Nietzsche envisioned satyrs as essentially humans stripped down to their most basic and bestial instincts. In 1908, the French painter Henri Matisse produced his own Nymph and Satyr painting, in which the animal nature of the satyr is drastically minimized. The satyr is given human legs, but is exceptionally hairy. The seduction element is removed altogether; the satyr simply extends his arms towards the nymph, who lies on the ground, defeated. Penny Florence writes that the "generic scene displays little sensuality" and that the main factor distinguishing it is its tone, because "[i]t does not seem convincing as a rape, despite the nymph's reluctance." In 1912, Vaslav Nijinsky choreographed Debussy's symphonic poem Prelude to the Afternoon of a Faun as a ballet and danced in it as the lead role of the faun. The choreography of the ballet and Nijinsky's performance were both highly erotic and sexually charged, causing widespread scandal among upper-class Parisians. In the 1980 biographical film Nijinsky, directed by Herbert Ross, Nijinsky, who is played by George de la Peña, is portrayed as actually masturbating on stage in front of the entire live audience during the climax of the dance. The 1917 Italian silent film Il Fauno, directed by Febo Mari, is about a statue of a faun who comes to life and falls in love with a female model. Fauns appear in the animated dramatization of Ludwig van Beethoven's Symphony No. 6 (1808) in the 1940 Disney animated film Fantasia. Their goat-legs are portrayed as brightly colored, but their hooves are black. They play the Pan pipes and, like traditional satyrs and fauns, are portrayed as mischievous. One young faun plays hide-and-seek with a unicorn and imitates a statue of a faun atop a pedestal. Though the fauns are not portrayed as overtly sexual, they do assist the Cupids in pairing the centaurs into couples. A drunken Bacchus appears in the same scene. A faun named Mr. Tumnus appears in the classic juvenile fantasy novel The Lion, the Witch and the Wardrobe (1950) by C. S. Lewis. Mr. Tumnus has goat legs and horns, but also a tail long enough for him to carry it draped over his arm to prevent it from dragging in the snow. He is a domesticated figure who lacks the bawdiness and hypersexuality that characterized classical satyrs and fauns. Instead, Mr. Tumnus wears a scarf and carries an umbrella and lives in a cozy cave with a bookshelf with works such as The Life and Letters of Silenus, Nymphs and their Ways, and Is Man a Myth?. The satyr has appeared in all five editions of the Dungeons & Dragons role-playing game, having been introduced in 1976 in the earliest edition, in Supplement IV: Gods, Demi-Gods & Heroes (1976), then in the first edition of the Monster Manual (1977), where it is described as a sylvan woodland inhabitant primarily interested in sport such as frolicking, piping, and chasing wood nymphs. The life history of satyrs was further detailed in Dragon No. 155 (March 1990), in "The Ecology of the Satyr". The satyr was later detailed as a playable character race in The Complete Book of Humanoids (1993), and is later presented as a playable character race again in Player's Option: Skills & Powers (1995). The satyr appears in the Monster Manual for the 3.0 edition. Savage Species (2003) presented the satyr as both a race and a playable class. The satyr appears in the revised Monster Manual for version 3.5 and also appears in the Monster Manual for the 4th edition, and as a playable character race in the Heroes of the Feywild sourcebook (2011). Matthew Barney's art video Drawing Restraint 7 (1993) includes two satyrs wrestling in the backseat of a moving limousine. A satyr named Grover Underwood appears in the young adult fantasy novel The Lightning Thief (2005) by American author Rick Riordan, as well as in subsequent novels in the series Percy Jackson & the Olympians. Though consistently referred to as a "satyr", Grover is described as having goat legs, pointed ears, and horns. Grover is not portrayed with the sexually obscene traits that characterized classical Greek satyrs. Instead, he is the loyal protector to the main character Percy Jackson, who is the son of a mortal woman and the god Poseidon. See also Notes References External links |
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[SOURCE: https://en.wikipedia.org/wiki/War_on_terror] | [TOKENS: 15868] |
Contents War on terror The war on terror, officially the Global War on Terrorism (GWOT), is a global military campaign initiated by the United States in response to the September 11 attacks in 2001. A global conflict spanning multiple wars, some researchers and political scientists have argued that it replaced the Cold War. The main targets of the campaign were militant Islamist movements such as al-Qaeda, the Taliban and their allies. Other major targets included the Ba'athist regime in Iraq, which was deposed in an invasion in 2003, and various militant factions that fought during the ensuing insurgency. Following its territorial expansion in 2014, the Islamic State also emerged as a key adversary of the United States. Starting in 2025, Operation Southern Spear emerged as an extension of the war on terror adapted to combat narcoterrorism, with the US government utilizing the same legal frameworks established since 2001 to justify the use of lethal force. Some analysts have identified this new approach as a hybridization of the war on terror and the war on drugs. The term "war on terror" uses war as a metaphor to describe a variety of actions which fall outside the traditional definition of war. US president George W. Bush first used the term "war on terrorism" on 16 September 2001, and then "war on terror" a few days later in a formal speech to Congress. Bush indicated the enemy of the war on terror as "a radical network of terrorists and every government that supports them". The initial conflict was aimed at al-Qaeda, with the main theater in Afghanistan and Pakistan, a region that would later be referred to as "AfPak". The term "war on terror" was immediately criticized by individuals including Richard Myers, then chairman of the Joint Chiefs of Staff, and eventually more nuanced terms came to be used by the Bush administration to define the campaign. While "war on terror" was never used as a formal designation of US operations, a Global War on Terrorism Service Medal was and is issued by the US Armed Forces. According to the Costs of War Project, the post-9/11 wars of the campaign have displaced 38 million people, the second largest number of forced displacements of any conflict since 1900, and caused more than 4.5 million deaths (direct and indirect) in Afghanistan, Iraq, Libya, Pakistan, Somalia, Syria and Yemen. They also estimate that it has cost the US Treasury over $8 trillion. While support for the "war on terror" was high among the American public during its initial years, it had become deeply unpopular by the late 2000s. Controversy over the war has focused on its morality, casualties, and continuity, with critics questioning government measures that infringed civil liberties and human rights. Critics have notably described the Patriot Act as "Orwellian" due to its substantial expansion of the federal government's surveillance powers. Controversial practices of coalition forces have been condemned, including drone warfare, surveillance, torture, extraordinary rendition, and various war crimes. The participating governments have been criticized for implementing authoritarian measures, repressing minorities, fomenting Islamophobia globally, and causing negative impacts to health and environment. Security analysts assert that there is no military solution to the conflict, pointing out that terrorism is not an identifiable enemy, and have emphasized the importance of negotiations and political solutions to resolve the underlying roots of the crises. Etymology The phrase war on terror was used to refer specifically to the military campaign led by the United States, the United Kingdom, and allied countries against organizations and regimes identified by them as terrorist, and usually excludes other independent counter-terrorist operations and campaigns such as those by Russia and India. The conflict has also been referred to by other names, such as "World War III", "World War IV" (assuming the Cold War was World War III), "Bush's War on Terror", "The Long War", "The Forever War", "The Global War on Terror", "The War Against al-Qaeda", or "The War of Terror". The phrase "war against terrorism" existed in North American popular culture and US political parlance prior to the war on terror. But it was not until the 11 September attacks that it emerged as a globally recognizable phrase and part of everyday lexicon. Tom Brokaw, having just witnessed the collapse of one of the towers of the World Trade Center, declared "Terrorists have declared war on [America]." On 16 September 2001, at Camp David, US president George W. Bush used the phrase war on terrorism in an ostensibly unscripted comment when answering a journalist's question about the impact of enhanced law enforcement authority given to the U.S. surveillance agencies on Americans' civil liberties: "This is a new kind of—a new kind of evil. And we understand. And the American people are beginning to understand. This crusade, this war on terrorism is going to take a while. And the American people must be patient. I'm going to be patient." The reference to Crusades became subject to heavy criticism due to its controversial connotations in the Muslim world and historical Muslim-Christian relations. On 20 September 2001, during a televised address to a joint session of Congress, George Bush said, "Our war on terror begins with al Qaeda, but it does not end there. It will not end until every terrorist group of global reach has been found, stopped and defeated." Both the term and the policies it denotes have been a source of ongoing controversy, as various critics and organizations like Amnesty International have argued that it has been used to justify unilateral preventive war, human rights abuses and other violations of international law. The political theorist Richard Jackson has argued that "the 'war on terrorism' [...] is simultaneously a set of actual practices—wars, covert operations, agencies, and institutions—and an accompanying series of assumptions, beliefs, justifications, and narratives—it is an entire language or discourse". Jackson cites, among many examples, a statement by John Ashcroft that "the attacks of September 11 drew a bright line of demarcation between the civil and the savage". Administration officials also described "terrorists" as hateful, treacherous, barbarous, mad, twisted, perverted, without faith, parasitical, inhuman, and, most commonly, evil. Americans, in contrast, were described as brave, loving, generous, strong, resourceful, heroic, and respectful of human rights. Denouncing the remarks of George W. Bush, Osama Bin Laden stated during an interview on 21 October 2001: "The events proved the extent of terrorism that America exercises in the world. Bush stated that the world has to be divided in two: Bush and his supporters, and any country that doesn't get into the global crusade is with the terrorists. What terrorism is clearer than this? Many governments were forced to support this "new terrorism." In April 2007, the British government announced publicly that it was abandoning the use of the phrase "war on terror" as they found it to be less than helpful. This was explained later by Lady Eliza Manningham-Buller. In her 2011 Reith lecture, the former head of MI5 said that the 9/11 attacks were "a crime, not an act of war. So I never felt it helpful to refer to a war on terror." US president Barack Obama rarely used the term, but in his inaugural address on 20 January 2009, he stated: "Our nation is at war, against a far-reaching network of violence and hatred." In March 2009 the Defense Department officially changed the name of operations from "Global War on Terror" to "Overseas Contingency Operation" (OCO). In March 2009, the Obama administration requested that Pentagon staff members avoid the use of the term and instead to use "Overseas Contingency Operation". Basic objectives of the Bush administration "war on terror", such as targeting al Qaeda and building international counterterrorism alliances, remained in place. In May 2010, the Obama administration published a report outlining its National Security Strategy. The document dropped the Bush-era phrase "global war on terror" and reference to "Islamic extremism," and stated, "This is not a global war against a tactic—terrorism, or a religion—Islam. We are at war with a specific network, al-Qaeda, and its terrorist affiliates who support efforts to attack the United States, our allies, and partners." Usage of the term "war on terror" was initially discontinued in May 2010 and again in May 2013. On 23 May 2013, US president Barack Obama announced that the "war on terrorism" was over, saying that the US would not wage war against a tactic but would instead focus on a specific group of terrorist networks. Other American military campaigns during the 2010s have also been considered part of the "war on terror" by individuals and the media. The rise of the Islamic State in Iraq and Syria during 2014–2015 led to the global Operation Inherent Resolve, and an international campaign to destroy the terrorist organization. This was considered to be another campaign of the "war on terror". In December 2012, Jeh Johnson, the General Counsel of the Department of Defense, speaking at Oxford University, stated that the war against al-Qaeda would end when the terrorist group had been weakened so that it was no longer capable of "strategic attacks" and had been "effectively destroyed." At that point, the war would no longer be an armed conflict under international law, and the military fight could be replaced by a law enforcement operation. In May 2013, two years after the killing of Osama bin Laden, Barack Obama delivered a speech that employed the term global war on terror put in quotation marks (as officially transcribed by the White House): "Now, make no mistake, terrorists still threaten our nation. ... In Afghanistan, we will complete our transition to Afghan responsibility for that country's security. ... Beyond Afghanistan, we must define our effort not as a boundless 'global war on terror,' but rather as a series of persistent, targeted efforts to dismantle specific networks of violent extremists that threaten America. In many cases, this will involve partnerships with other countries." Nevertheless, in the same speech, in a bid to emphasize the legality of military actions undertaken by the US, noting that Congress had authorised the use of force, he went on to say, "Under domestic law, and international law, the United States is at war with al Qaeda, the Taliban, and their associated forces. We are at war with an organization that right now would kill as many Americans as they could if we did not stop them first. So this is a just war—a war waged proportionally, in last resort, and in self-defense." Nonetheless, the use of the phrase "war on terror" persists in US politics. In 2017, for example, US vice president Mike Pence called the 1983 Beirut barracks bombing "the opening salvo in a war that we have waged ever since—the global war on terror." Background In May 1996, the group World Islamic Front for Jihad Against Jews and Crusaders (WIFJAJC), sponsored by Osama bin Laden (and later re-formed as al-Qaeda), started forming a large base of operations in Afghanistan, where the Islamist extremist regime of the Taliban had seized power earlier in the year. In August 1996, Bin Laden declared jihad against the United States. In February 1998, Osama bin Laden signed a fatwa, as head of al-Qaeda, declaring war on the West and Israel; in May al-Qaeda released a video declaring war on the US and the West. On 7 August 1998, al-Qaeda struck the U.S. embassies in Kenya and Tanzania, killing 224 people, including 12 Americans. In retaliation, US president Bill Clinton launched Operation Infinite Reach, a bombing campaign in Sudan and Afghanistan against targets the US asserted were associated with WIFJAJC, although others have questioned whether a pharmaceutical plant in Sudan was used as a chemical warfare facility. The plant produced much of the region's antimalarial drugs and around 50% of Sudan's pharmaceutical needs. The strikes failed to kill any leaders of WIFJAJC or the Taliban. Next came the 2000 millennium attack plots, which included an attempted bombing of Los Angeles International Airport. On 12 October 2000, the USS Cole bombing occurred near the port of Yemen, and 17 US Navy sailors were killed. On the morning of 11 September 2001, nineteen men hijacked four jet airliners, all of them bound for California. Once the hijackers assumed control of the jet airliners, they told the passengers that they had a bomb on board and would spare the lives of passengers and crew once their demands were met—no passenger and crew actually suspected that they would use the jet airliners as suicide weapons since it had never happened before in history, and many previous hijacking attempts had been resolved with the passengers and crew escaping unharmed after obeying the hijackers. The hijackers—members of al-Qaeda's Hamburg cell—intentionally crashed two jet airliners into the Twin Towers of the World Trade Center in New York City. Both buildings collapsed within two hours from fire damage related to the crashes, destroying nearby buildings and damaging others. The hijackers crashed a third jet airliner into the Pentagon in Arlington County, Virginia, just outside Washington, D.C. The fourth jet airliner crashed into a field near Shanksville, Pennsylvania, after some of its passengers and flight crew attempted to retake control of the jet airliners, which the hijackers had redirected toward Washington, D.C., to target the White House or the US Capitol. None of the flights had any survivors. A total of 2,977 victims and the 19 hijackers perished in the attacks. Fifteen of the nineteen were citizens of Saudi Arabia, and the others were from the United Arab Emirates (2), Egypt, and Lebanon. On 13 September, for the first time ever, NATO invoked Article 5 of the North Atlantic Treaty, which commits each member state to consider an armed attack against one member state to be an armed attack against them all. The invocation of Article 5 led to Operation Eagle Assist and Operation Active Endeavour. On 18 September 2001, President Bush signed the Authorization for Use of Military Force Against Terrorists passed by Congress a few days prior; the authorization is still active to this day and has been used to justify numerous military actions. American objectives The Authorization for Use of Military Force Against Terrorists or "AUMF" was made law on 14 September 2001, to authorize the use of United States Armed Forces against those responsible for 11 September attacks. It authorized the president to use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on 11 September 2001, or harbored such organizations or persons, to prevent any future acts of international terrorism against the United States by such nations, organizations or individuals. Congress declares this is intended to constitute specific statutory authorization within the meaning of section 5(b) of the War Powers Resolution of 1973. The George W. Bush administration defined the following objectives in the war on terror: The 2001 AUMF has authorized the US president to launch military operations across the world without any congressional oversight or transparency. Between 2018 and 2020 alone, US forces initiated what it labelled "counter-terror" activities in 85 countries. Of these, the 2001 AUMF has been used to launch classified military campaigns in at least 22 countries. The 2001 AUMF has been widely perceived as a bill that grants the president powers to unilaterally wage perpetual "world wide wars". Timeline Operation Enduring Freedom Operation Enduring Freedom is the official name used by the Bush administration for the War in Afghanistan, together with three smaller military actions, under the umbrella of the global war on terror. These global operations are intended to seek out and destroy any al-Qaeda fighters or affiliates. Originally, the campaign was named "Eternal Justice" but due to widespread controversy and condemnation in the Muslim world, the phrasing was changed to "Enduring Freedom". On 20 September 2001, in the wake of the September 11 attacks, George W. Bush delivered an ultimatum to the Taliban government of Afghanistan, the Islamic Emirate of Afghanistan, to turn over Osama bin Laden and al-Qaeda leaders operating in the country or face attack. The Taliban demanded evidence of bin Laden's link to 11 September attacks and, if such evidence warranted a trial, they offered to handle such a trial in an Islamic Court. Subsequently, in October 2001, US forces (with UK and coalition allies) invaded Afghanistan to oust the Taliban regime. On 7 October 2001, the official invasion began with British and US forces conducting airstrike campaigns over enemy targets. Shortly after, Bush rejected a Taliban offer to hand over bin Laden on the condition the bombing campaign was halted, and by mid-November, Kabul, the capital city of Afghanistan, fell. The remaining al-Qaeda and Taliban remnants fell back to the rugged mountains of eastern Afghanistan, mainly Tora Bora. In December, Coalition forces (the US and its allies) fought within that region. It is believed that Osama bin Laden escaped into Pakistan during the battle. In March 2002, the US and other NATO and non-NATO forces launched Operation Anaconda with the goal of destroying any remaining al-Qaeda and Taliban forces in the Shah-i-Kot Valley and Arma Mountains of Afghanistan. The Taliban suffered heavy casualties and evacuated the region. The Taliban regrouped in western Pakistan and began to unleash an insurgent-style offensive against Coalition forces in late 2002. Throughout southern and eastern Afghanistan, firefights broke out between the surging Taliban and Coalition forces. Coalition forces responded with a series of military offensives and an increase of troops in Afghanistan. In February 2010, Coalition forces launched Operation Moshtarak in southern Afghanistan along with other military offensives in the hopes that they would destroy the Taliban insurgency once and for all. Peace talks were also underway between Taliban affiliated fighters and Coalition forces. In September 2014, Afghanistan and the United States signed a security agreement, which allowed the United States and NATO forces to remain in Afghanistan until at least 2024. However, on 29 February 2020, the United States and the Taliban signed a conditional peace deal in Doha which required that US troops withdraw from Afghanistan within 14 months so long as the Taliban cooperated with the terms of the agreement not to "allow any of its members, other individuals or groups, including Al Qaeda, to use the soil of Afghanistan to threaten the security of the United States and its allies". The Afghan government was not a party to the deal and rejected its terms regarding release of prisoners. After Joe Biden became president, he moved back the target withdrawal date to 31 August 2021. On 15 August 2021, the Afghan capital Kabul fell to a surprisingly effective Taliban offensive, ending the war in Afghanistan. The US military and NATO troops took control of Kabul's Hamid Karzai International Airport for use in Operation Allies Refuge and the large-scale evacuation of foreign citizens and certain vulnerable Afghans, executed in cooperation with the Taliban. On 30 August 2021, the United States completed its hasty withdrawal of its military from Afghanistan. The withdrawal was heavily criticized both domestically and abroad for being chaotic and haphazard, as well as for lending more momentum to the Taliban offensive. However, many European countries followed suit, including Britain, Germany, Italy, and Poland. Despite evacuating over 120,000 people, the large-scale evacuation has also been criticized for leaving behind hundreds of American citizens, residents, and family members. The NATO-led International Security Assistance Force (ISAF) was created in December 2001 to assist the Afghan Transitional Administration and the first post-Taliban elected government. With a renewed Taliban insurgency, it was announced in 2006 that ISAF would replace the US troops in the province as part of Operation Enduring Freedom. The British 16th Air Assault Brigade (later reinforced by Royal Marines) formed the core of the force in southern Afghanistan, along with troops and helicopters from Australia, Canada and the Netherlands. The initial force consisted of roughly 3,300 British, 2,000 Canadian, 1,400 from the Netherlands and 240 from Australia, along with special forces from Denmark and Estonia and small contingents from other nations. The monthly supply of cargo containers through Pakistani route to ISAF in Afghanistan is over 4,000 costing around 12 billion in Pakistani Rupees. In January 2002, the United States Special Operations Command, Pacific deployed to the Philippines to advise and assist the Armed Forces of the Philippines in combating Filipino Islamist groups. The operations were mainly focused on removing the Abu Sayyaf group and Jemaah Islamiyah (JI) from their stronghold on the island of Basilan. The second portion of the operation was conducted as a humanitarian program called "Operation Smiles". The goal of the program was to provide medical care and services to the region of Basilan as part of a "Hearts and Minds" program. Joint Special Operations Task Force – Philippines disbanded in June 2014, ending a successful 12-year mission. After JSOTF-P had disbanded, as late as November 2014, American forces continued to operate in the Philippines under the name "PACOM Augmentation Team", until 24 February 2015. On 1 September 2017, US Secretary of Defense Jim Mattis designated Operation Pacific Eagle – Philippines (OPE-P) as a contingency operation to support the Philippine government and the military in their efforts to isolate, degrade, and defeat the affiliates of ISIL (collectively referred to as ISIL-Philippines or ISIL-P) and other terrorist organisations in the Philippines. By 2018, American operations within the Philippines against terrorist groups involved as many as 300 advisers. Operation Enduring Freedom – Trans Sahara (OEF-TS), now Operation Juniper Shield, is the name of the military operation conducted by the US and partner nations in the Sahara/Sahel region of Africa, consisting of counter-terrorism efforts and policing of arms and drug trafficking across central Africa. The conflict in northern Mali began in January 2012 with radical Islamists (affiliated to al-Qaeda) advancing into northern Mali. The Malian government had a hard time maintaining full control over their country. The fledgling government requested support from the international community on combating the Islamic militants. In January 2013, France intervened on behalf of the Malian government's request and deployed troops into the region. They launched Operation Serval on 11 January 2013, with the hopes of dislodging the al-Qaeda affiliated groups from northern Mali. Operation Enduring Freedom – Horn of Africa is an extension of Operation Enduring Freedom. Unlike other operations contained in Operation Enduring Freedom, OEF-HOA does not have a specific organization as a target. OEF-HOA instead focuses its efforts to disrupt and detect militant activities in the region and to work with willing governments to prevent the reemergence of militant cells and activities. In October 2002, the Combined Joint Task Force – Horn of Africa (CJTF-HOA) was established in Djibouti at Camp Lemonnier. It contains approximately 2,000 personnel including US military and special operations forces (SOF) and coalition force members, Combined Task Force 150 (CTF-150). Task Force 150 consists of ships from a shifting group of nations, including Australia, Canada, France, Germany, Italy, Netherlands, Pakistan, New Zealand and the United Kingdom. The primary goal of the coalition forces is to monitor, inspect, board and stop suspected shipments from entering the Horn of Africa region and affecting the United States' Operation Iraqi Freedom. Included in the operation is the training of selected armed forces units of the countries of Djibouti, Kenya and Ethiopia in counter-terrorism and counter-insurgency tactics. Humanitarian efforts conducted by CJTF-HOA include rebuilding of schools and medical clinics and providing medical services to those countries whose forces are being trained. The program expands as part of the Trans-Saharan Counterterrorism Initiative as CJTF personnel also assist in training the armed forces of Chad, Niger, Mauritania and Mali. However, the war on terror does not include Sudan, where over 400,000 have died in an ongoing civil war. On 1 July 2006, a Web-posted message purportedly written by Osama bin Laden urged Somalis to build an Islamic state in the country and warned western governments that the al-Qaeda network would fight against them if they intervened there. The Prime Minister of Somalia claimed that three "terror suspects" from the 1998 United States embassy bombings are being sheltered in Kismayo. On 30 December 2006, al-Qaeda deputy leader Ayman al-Zawahiri called upon Muslims worldwide to fight against Ethiopia and the TFG in Somalia. On 8 January 2007, the US launched the Battle of Ras Kamboni by bombing Ras Kamboni using AC-130 gunships. On 14 September 2009, US Special Forces killed two men and wounded and captured two others near the Somali village of Baarawe. Witnesses claim that helicopters used for the operation launched from French-flagged warships, but that could not be confirmed. A Somali-based al-Qaida affiliated group, the Al-Shabaab, has verified the death of "sheik commander" Saleh Ali Saleh Nabhan along with an unspecified number of militants. Nabhan, a Kenyan, was wanted in connection with the 2002 Mombasa attacks. Military operations by country During his 2002 State of the Union Address, George W. Bush accused North Korea, Iran and Iraq of propping up state-sponsored terrorism and pursuing Weapons of Mass Destruction. These countries were portrayed as a global threat and categorised under the terminology referred to as "Axis of evil". Regarding Iraq, Bush alleged: "Iraq continues to flaunt its hostility toward America and to support terror. The Iraqi regime has plotted to develop anthrax and nerve gas and nuclear weapons for over a decade. This is a regime that has already used poison gas to murder thousands of its own citizens, leaving the bodies of mothers huddled over their dead children. This is a regime that agreed to international inspections, then kicked out the inspectors. This is a regime that has something to hide from the civilized world." In October 2002, United States Congress passed the "Authorization for Use of Military Force Against Iraq Resolution of 2002", which empowered the US president to order military attack against Iraq. On 5 February 2003, Secretary of State Colin Powell made a presentation before the UN Security Council which claimed to implicate Iraq in building a secret WMD program and having ties to Al-Qaeda. On 17 March 2003, Bush issued an ultimatum to Saddam Hussein and his two sons to flee Iraq within a 48-hour deadline or else face "military conflict". Justifying his policy Bush declared: "Terrorists and terror states do not reveal these threats with fair notice, in formal declarations—and responding to such enemies only after they have struck first is not self-defense, it is suicide. The security of the world requires disarming Saddam Hussein now." The Iraq War began in March 2003 with an air campaign, which was immediately followed by a US-led ground invasion. The Bush administration cited UNSC Resolution 1441, which warned of "serious consequences" for violations such as Iraq possessing weapons of mass destruction. The Bush administration also stated the Iraq War was part of the war on terror, a claim later questioned and contested. Iraq had been listed as a state sponsor of terrorism by the US since 1990, when Saddam Hussein invaded Kuwait. The first ground attack came at the Battle of Umm Qasr on 21 March 2003, when a combined force of British, US and Polish forces seized control of the port city of Umm Qasr. Baghdad, Iraq's capital city, fell to US troops in April 2003 and Saddam Hussein's government quickly dissolved. On 1 May 2003, Bush announced that major combat operations in Iraq had ended. However, an insurgency arose against the US-led coalition and the newly developing Iraqi military and post-Saddam government. The rebellion, which included al-Qaeda-affiliated groups, led to many coalition casualties. Other elements of the insurgency were led by fugitive members of President Hussein's Ba'ath regime, which included Iraqi nationalists and pan-Arabists. Many insurgency leaders were Islamists and claimed to be fighting a religious war to reestablish the Islamic Caliphate of centuries past. Saddam Hussein was captured by US forces in December 2003 and was executed in 2006. In 2004, the insurgent forces grew stronger. The US launched offensives on insurgent strongholds in cities like Najaf and Fallujah. In January 2007, President Bush presented a new strategy for Operation Iraqi Freedom based upon counter-insurgency theories and tactics developed by General David Petraeus. The Iraq War troop surge of 2007 was part of this "new way forward", which along with US backing of Sunni groups it had previously sought to defeat has been credited with a widely recognized dramatic decrease in violence by up to 80%.[citation needed] The war entered a new phase on 1 September 2010, with the official end of U.S. combat operations. President Obama ordered the withdrawal of most troops in 2011, but began redeploying forces in 2014 to fight the Islamic State group. As of July 2021, there were approximately 2,500 US troops in Iraq, who continue to assist in the mission to combat the remnants of IS. Following 11 September attacks, former president of Pakistan Pervez Musharraf sided with the US against the Taliban government in Afghanistan after an ultimatum by then US president George W. Bush. Musharraf agreed to give the US the use of three airbases for Operation Enduring Freedom. United States secretary of state Colin Powell and other US administration officials met with Musharraf. On 19 September 2001, Musharraf addressed the people of Pakistan and stated that, while he opposed military tactics against the Taliban, Pakistan risked being endangered by an alliance of India and the US if it did not cooperate. In 2006, Musharraf testified that this stance was pressured by threats from the US, and revealed in his memoirs that he had "war-gamed" the United States as an adversary and decided that it would end in a loss for Pakistan. On 12 January 2002, Musharraf gave a speech against Islamic extremism. He unequivocally condemned all acts of terrorism and pledged to combat Islamic extremism and lawlessness within Pakistan itself. He stated that his government was committed to rooting out extremism and made it clear that the banned militant organizations would not be allowed to resurface under any new name. He said, "the recent decision to ban extremist groups promoting militancy was taken in the national interest after thorough consultations. It was not taken under any foreign influence". In 2002, the Musharraf-led government took a firm stand against the jihadi organizations and groups promoting extremism, and arrested Maulana Masood Azhar, head of the Jaish-e-Mohammed, and Hafiz Muhammad Saeed, chief of the Lashkar-e-Taiba, and took dozens of activists into custody. An official ban was imposed on the groups on 12 January. Later that year, the Saudi born Zayn al-Abidn Muhammed Hasayn Abu Zubaydah was arrested by Pakistani officials during a series of joint US–Pakistan raids. Zubaydah is said to have been a high-ranking al-Qaeda official with the title of operations chief and in charge of running al-Qaeda training camps. Other prominent al-Qaeda members were arrested in the following two years, namely Ramzi bin al-Shibh, who is known to have been a financial backer of al-Qaeda operations, and Khalid Sheikh Mohammed, who at the time of his capture was the third highest-ranking official in al-Qaeda and had been directly in charge of the planning for 11 September attacks. In 2004, the Pakistan Army launched a campaign in the Federally Administered Tribal Areas of Pakistan's Waziristan region, sending in 80,000 troops. The goal of the conflict was to remove the al-Qaeda and Taliban forces in the area. After the fall of the Taliban regime, many members of the Taliban resistance fled to the Northern border region of Afghanistan and Pakistan where the Pakistani army had previously little control. With the logistics and air support of the United States, the Pakistani Army captured or killed numerous al-Qaeda operatives such as Khalid Sheikh Mohammed, wanted for his involvement in the USS Cole bombing, the Bojinka plot, and the killing of Wall Street Journal reporter Daniel Pearl. The United States has carried out a campaign of drone attacks on targets all over the Federally Administered Tribal Areas. However, the Pakistani Taliban still operates there. To this day it is estimated that 15 US soldiers were killed while fighting al-Qaeda and Taliban remnants in Pakistan since the war on terror began. Osama bin Laden, his wife, and son, were all killed on 2 May 2011, during a raid conducted by the United States special operations forces in Abbottabad, Pakistan. The use of drones by the Central Intelligence Agency in Pakistan to carry out operations associated with the global war on terror sparks debate over sovereignty and the laws of war. The US Government uses the CIA rather than the US Air Force for strikes in Pakistan to avoid breaching sovereignty through military invasion. The United States was criticized by[according to whom?] a report on drone warfare and aerial sovereignty for abusing the term 'global war on terror' to carry out military operations through government agencies without formally declaring war. After 11 September attacks, US economic and security aid to Pakistan spiked considerably. With the authorization of the Enhanced Partnership for Pakistan Act, Pakistan was granted US$7.5 billion over five years from FY2010–FY2014. The United States has conducted a series of military strikes on al-Qaeda militants in Yemen since the war on terror began. Yemen has a weak central government and a powerful tribal system that leaves large lawless areas open for militant training and operations. Al-Qaeda has a strong presence in the country. On 31 March 2011, AQAP declared the Al-Qaeda Emirate in Yemen after its captured most of Abyan Governorate. The US, in an effort to support Yemeni counter-terrorism efforts, increased their military aid package to Yemen from less than $11 million in 2006 to more than $70 million in 2009, as well as providing up to $121 million for development over the next three years. Current phase: Islamic State and focus on narcoterrorism (2021–present) During the 2020s, the war on terror has decreased in volume and intensity following the closure of the wars in Iraq (2011, with residual operations until 2021) and Afghanistan (complete withdrawal in 2021). This shift represents a transition from large-scale military interventions—with hundreds of thousands of troops, ground invasions, and prolonged occupations—to a more surgical, hybrid, and sustainable approach centered on intelligence, selective strikes, and regional alliances. For their part, the US and NATO prioritize cyber defense, online counter-narratives, and cooperation with allies, which reduces media "noise" and their own casualties. On July 31, 2022, Ayman al-Zawahiri, Osama bin Laden's key successor, was killed in a US drone strike in Kabul, Afghanistan, marking the end of decades of centralized leadership in al-Qaeda. As of 2025, various global operations in the campaign are ongoing, including a US military intervention in Somalia. Meanwhile, in 2025, airstrikes continue in Yemen. Meanwhile, ISIS–K remains a structural terrorist cell due to its decentralized and transnational operational capacity, evidenced by a series of high-impact attacks—including the January 2024 suicide bombings in Kerman, Iran (94 deaths), the March 2024 assault on Crocus City Hall in Moscow (more than 140 fatalities), the foiled August 2024 plot against Taylor Swift concerts in Vienna, and the January 1, 2025 vehicle-and-explosives attack in New Orleans (at least 15 dead)—which demonstrate its ability to project lethal violence far beyond its core bases in Afghanistan and Pakistan by exploiting security vacuums created by the 2021 US withdrawal and the instability in Syria following the December 2024 collapse of the Assad regime. This resilience is sustained by highly sophisticated digital propaganda that has revitalized recruitment efforts among Central Asian diasporas (especially Tajiks) in Russia, Türkiye, Europe, and the United States via encrypted platforms; and by robust logistical and financial networks that enable the mobilization of battle-hardened fighters (estimated at 4,000–6,000 in Afghanistan and more than 2,500 active operatives in Syria and Iraq according to 2025 UN and CENTCOM reports). In 2025, the US' military escalation against alleged narcoterrorists linked to Venezuela—such as the Cartel of the Suns, the Tren de Aragua and the National Liberation Army—reframed Latin American narcoterrorism as a global threat, which in turn opened the door to a possible invasion of Venezuelan territory. The designation of the Cartel of the Suns as a Foreign Terrorist Organization, along with the deployment of the USS Gerald R. Ford near Venezuelan waters and a series of strikes against vessels labeled as narcotrafficker assets, represented a turning point in the region: the shift was no longer about interdiction, but about counterterrorism within the Americas. Likewise, Operation Southern Spear has raised new questions about whether a second war on terror has begun. By adopting the same legal and rhetorical framework used during the post-9/11 war on terror, treating traffickers as “unlawful combatants” and justifying lethal force even in international waters, Washington opened the door to broader military operations—including targeted strikes on criminal-controlled areas, direct intervention, and even potential ground actions if the threat were deemed systemic. This strategic realignment could pull other regional actors into a collective security framework, legitimize multilateral military cooperation, and reshape hemispheric security under an anti-terror paradigm, extending far beyond traditional anti-drug efforts. On December 15, 2025, the US carried out Operation Hawkeye Strike against the Islamic State following the Palmyra attack. On 25 December 2025, US president Donald Trump authorized strikes against Islamic State militants in northwest Nigeria. Other military operations The Obama administration began to re-engage in Iraq with a series of airstrikes aimed at ISIL starting on 10 August 2014. On 9 September 2014, President Obama said that he had the authority he needed to take action to destroy the militant group known as the Islamic State of Iraq and the Levant, citing the 2001 Authorization for the Use of Military Force Against Terrorists, and thus did not require additional approval from Congress. The following day on 10 September 2014 President Barack Obama made a televised speech about ISIL, which he stated: "Our objective is clear: We will degrade, and ultimately destroy, ISIL through a comprehensive and sustained counter-terrorism strategy". Obama has authorized the deployment of additional US Forces into Iraq, as well as authorizing direct military operations against ISIL within Syria. On the night of 21/22 September the United States, Saudi Arabia, Bahrain, the UAE, Jordan and Qatar started air attacks against ISIL in Syria. In October 2014, it was reported that the US Department of Defense considers military operations against ISIL as being under Operation Enduring Freedom in regards to campaign medal awarding. On 15 October, the military intervention became known as "Operation Inherent Resolve". With the rise of the Islamic State in Iraq and the Levant (ISIL), jihadist offshoots sprung up in regions around the world, including the Philippines. The Maute group, composed of former Moro Islamic Liberation Front guerrillas and foreign fighters led by Omar Maute, the alleged founder of a Dawlah Islamiya, declared loyalty to ISIL and began clashing with Philippine security forces and staging bombings. On 23 May 2017, the group attacked the city of Marawi, resulting in the bloody Battle of Marawi that lasted 5 months. After the decisive battle, remnants of the group were reportedly still recruiting in 2017 and 2018. NBC News reported that in mid-2014, ISIL had about 1,000 fighters in Libya. Taking advantage of a power vacuum in the center of the country, far from the major cities of Tripoli and Benghazi, ISIL expanded rapidly over the next 18 months. Local militants were joined by jihadists from the rest of North Africa, the Middle East, Europe and the Caucasus. The force absorbed or defeated other Islamist groups inside Libya and the central ISIL leadership in Raqqa, Syria, began urging foreign recruits to head for Libya instead of Syria. ISIL seized control of the coastal city of Sirte in early 2015 and then began to expand to the east and south. By the beginning of 2016, it had effective control of 120 to 150 miles of coastline and portions of the interior and had reached Eastern Libya's major population center, Benghazi. In spring 2016, AFRICOM estimated that ISIL had about 5,000 fighters in its stronghold of Sirte. However, the indigenous rebel groups who had staked their claims to Libya and turned their weapons on ISIL—with the help of airstrikes by Western forces, including US drones, the Libyan population resented the outsiders who wanted to establish a fundamentalist regime on their soil. Militias loyal to the new Libyan unity government, plus a separate and rival force loyal to a former officer in the Gaddafi regime, launched an assault on ISIL outposts in Sirte and the surrounding areas that lasted for months. According to US military estimates, ISIL ranks shrank to somewhere between a few hundred and 2,000 fighters. In August 2016, the US military began airstrikes that, along with continued pressure on the ground from the Libyan militias, pushed the remaining ISIL fighters back into Sirte. In all, US drones and planes hit ISIL nearly 590 times, the Libyan militias reclaimed the city in mid-December. On 18 January 2017, ABC News reported that two USAF B-2 bombers struck two ISIL camps 28 miles (45 km) south of Sirte, the airstrikes targeted between 80 and 100 ISIL fighters in multiple camps, an unmanned aircraft also participated in the airstrikes. NBC News reported that as many as 90 ISIL fighters were killed in the strike, a US defense official said that "This was the largest remaining ISIL presence in Libya," and that "They have been largely marginalized, but I am hesitant to say they have been eliminated in Libya." In October 2015, the US began deploying 300 soldiers to Cameroon, with the invitation of the Cameroonian government, to support African forces in a non-combat role in their fight against ISIL insurgency in that country. The troops' primary missions will revolve around providing intelligence support to local forces as well as conducting reconnaissance flights. Operation Active Endeavour was a naval operation of NATO started in October 2001 in response to 11 September attacks. It operated in the Mediterranean and was designed to prevent the movement of militants or weapons of mass destruction and to enhance the security of shipping in general. In a 'Letter to American People' written by Osama bin Laden in 2002, he stated that one of the reasons he was fighting America is because of its support of India on the Kashmir issue. Indian sources claimed that in 2006, al-Qaeda claimed they had established a wing in Kashmir; this worried the Indian government. India also argued that al-Qaeda has strong ties with the Kashmir militant groups Lashkar-e-Taiba and Jaish-e-Mohammed in Pakistan. While on a visit to Pakistan in January 2010, US Defense Secretary Robert Gates stated that al-Qaeda was seeking to destabilize the region and planning to provoke a nuclear war between India and Pakistan. In September 2009, a US drone strike reportedly killed Ilyas Kashmiri, who was the chief of Harkat-ul-Jihad al-Islami, a Kashmiri militant group associated with al-Qaeda. Kashmiri was described by Bruce Riedel as a 'prominent' al-Qaeda member, while others described him as the head of military operations for al-Qaeda. Waziristan had now become the new battlefield for Kashmiri militants, who were now fighting NATO in support of al-Qaeda. On 8 July 2012, Al-Badar Mujahideen, a breakaway faction of Kashmir centric terror group Hizbul Mujahideen, on the conclusion of their two-day Shuhada Conference called for a mobilization of resources for continuation of jihad in Kashmir. In June 2021, an air force station in Jammu (in India-administered Kashmir) was attacked by drone. Investigators were uncertain whether a state or non-state actor initiated the attack. As part of the Iran–Israel proxy conflict and the Iran–Saudi Arabia proxy conflict, both Israel and Saudi Arabia has engaged in its own war on terror against Iranian-backed insurgent groups, and against Al-Qaeda in the Arabian Peninsula (AQAP) and Islamic State in Saudi Arabia's case. Although Israel did not directly participate in the 2003 invasion of Iraq, it reportedly urged the US not to delay an attack on Saddam Hussein. Before the US-led invasion of Iraq in 2003, Israeli intelligence reportedly provided information to Washington. Israel launched a 34-day military conflict against Hezbollah in Lebanon, northern Israel and the Golan Heights during mid-2006. In Saudi Arabia's case, its own war on terror has been heightened by its intervention in the Yemeni civil war since March 26, 2015. Both Al-Qaeda in the Arabian Peninsula (AQAP) and Islamic State had a presence in Yemen before the Saudi-led intervention. Colombia has also engaged on its own war on terror, as terrorism by both guerrillas and paramilitaries remains a major concern in the country since the escalation of armed violence in the 2000s in the context of the Colombian conflict. Álvaro Uribe's presidency, in particular, was marked by a significant focus on counter-terrorism and counterinsurgency. The counterterrorism measures of Plan Colombia acquired further expansion during the presidency of George W. Bush and an important focus on national security after the events of 9/11, as the threat of global terrorism received greater attention. In the 2010s, the People's Republic of China has also been engaged in its own war on terror, predominantly a domestic campaign in response to violent actions by Uyghur separatist movements in the Xinjiang conflict. This campaign was widely criticized in international media due to the perception that it unfairly targets and persecutes Chinese Muslims, potentially resulting in a negative backlash from China's predominantly Muslim Uighur population. CCP general secretary Xi Jinping's regime has imprisoned up to two million Uyghurs and other Muslim ethnic minorities in Xinjiang internment camps, where they are reportedly subject to abuse and torture. Russia has also been engaged on its own, also largely internally focused, counter-terrorism campaign often termed a war on terror, during the Second Chechen War, the Insurgency in the North Caucasus, and the Russian military intervention in the Syrian Civil War. Like China's war on terror, Russia has also been focused on separatist and Islamist movements that use political violence to achieve their ends. International military support The invasion of Afghanistan is seen to have been the first action of this war, and initially involved forces from the United States, the United Kingdom, and the Afghan Northern Alliance. Since the initial invasion period, these forces were augmented by troops and aircraft from Australia, Canada, Denmark, France, Italy, Netherlands, New Zealand and Norway among others. In 2006, there were about 33,000 troops in Afghanistan. On 12 September 2001, less than 24 hours after 11 September attacks in New York City and Washington, D.C., NATO invoked Article 5 of the North Atlantic Treaty and declared the attacks to be an attack against all 19 NATO member countries. Australian Prime Minister John Howard also stated that Australia would invoke the ANZUS Treaty along similar lines. In the following months, NATO took a broad range of measures to respond to the threat of terrorism. On 22 November 2002, the member states of the Euro-Atlantic Partnership Council (EAPC) decided on a Partnership Action Plan against Terrorism, which explicitly states, "[The] EAPC States are committed to the protection and promotion of fundamental freedoms and human rights, as well as the rule of law, in combating terrorism." NATO started naval operations in the Mediterranean Sea designed to prevent the movement of terrorists or weapons of mass destruction as well as to enhance the security of shipping in general called Operation Active Endeavour. Support for the US cooled when America made clear its determination to invade Iraq in late 2002. Still, many of the "coalition of the willing" countries that unconditionally supported the US-led military action have sent troops to Afghanistan, particular neighboring Pakistan, which has disowned its earlier support for the Taliban and contributed tens of thousands of soldiers to the conflict. Pakistan was also engaged in the Insurgency in Khyber Pakhtunkhwa (a.k.a. Waziristan War or North-West Pakistan War). Supported by US intelligence, Pakistan attempted to remove the Taliban insurgency and al-Qaeda element from the northern tribal areas. Post–9/11 events inside the United States In addition to military efforts abroad, in the aftermath of 9/11, the Bush Administration increased domestic efforts to prevent future attacks. Various government bureaucracies that handled security and military functions were reorganized. A new cabinet-level agency called the United States Department of Homeland Security was created in November 2002 to lead and coordinate the largest reorganization of the US federal government since the consolidation of the armed forces into the Department of Defense.[citation needed] The Justice Department launched the National Security Entry-Exit Registration System for certain male non-citizens in the US, requiring them to register in person at offices of the Immigration and Naturalization Service. The USA PATRIOT Act of October 2001 dramatically reduces restrictions on law enforcement agencies' ability to search telephone, e-mail communications, medical, financial, and other records; eases restrictions on foreign intelligence gathering within the United States; expands the Secretary of the Treasury's authority to regulate financial transactions, particularly those involving foreign individuals and entities; and broadens the discretion of law enforcement and immigration authorities in detaining and deporting immigrants suspected of terrorism-related acts. The act also expanded the definition of terrorism to include domestic terrorism, thus enlarging the number of activities to which the USA PATRIOT Act's expanded law enforcement powers could be applied. A new Terrorist Finance Tracking Program monitored the movements of terrorists' financial resources (discontinued after being revealed by The New York Times). Global telecommunication usage, including those with no links to terrorism, is being collected and monitored through the NSA electronic surveillance program. The Patriot Act is still in effect. Political interest groups have stated that these laws remove important restrictions on governmental authority, and are a dangerous encroachment on civil liberties, possible unconstitutional violations of the Fourth Amendment. On 30 July 2003, the American Civil Liberties Union (ACLU) filed the first legal challenge against Section 215 of the Patriot Act, claiming that it allows the FBI to violate a citizen's First Amendment rights, Fourth Amendment rights, and right to due process, by granting the government the right to search a person's business, bookstore, and library records in a terrorist investigation, without disclosing to the individual that records were being searched. Also, governing bodies in many communities have passed symbolic resolutions against the act. In a speech on 9 June 2005, Bush said that the USA PATRIOT Act had been used to bring charges against more than 400 suspects, more than half of whom had been convicted. Meanwhile, the ACLU quoted Justice Department figures showing that 7,000 people have complained of abuse of the Act.[citation needed] The Defense Advanced Research Projects Agency (DARPA) began an initiative in early 2002 with the creation of the Total Information Awareness program, designed to promote information technologies that could be used in counter-terrorism. This program, facing criticism, has since been defunded by Congress.[citation needed] By 2003, 12 major conventions and protocols were designed to combat terrorism. These were adopted and ratified by many states. These conventions require states to co-operate on principal issues regarding unlawful seizure of aircraft, the physical protection of nuclear materials, and the freezing of assets of militant networks. In 2005, the UN Security Council adopted Resolution 1624 concerning incitement to commit acts of terrorism and the obligations of countries to comply with international human rights laws. Although both resolutions require mandatory annual reports on counter-terrorism activities by adopting nations, the United States and Israel have both declined to submit reports. In the same year, the United States Department of Defense and the Chairman of the Joint Chiefs of Staff issued a planning document, by the name "National Military Strategic Plan for the War on Terrorism", which stated that it constituted the "comprehensive military plan to prosecute the Global War on Terror for the Armed Forces of the United States...including the findings and recommendations of the 9/11 Commission and a rigorous examination with the Department of Defense". On 9 January 2007, the House of Representatives passed a bill, by a vote of 299–128, enacting many of the recommendations of the 9/11 Commission The bill passed in the US Senate, by a vote of 60–38, on 13 March 2007 and it was signed into law on 3 August 2007 by President Bush. It became Public Law 110–53. In July 2012, US Senate passed a resolution urging that the Haqqani Network be designated a foreign terrorist organization. The Office of Strategic Influence was secretly created after 9/11 for the purpose of coordinating propaganda efforts but was closed soon after being discovered. The Bush administration implemented the Continuity of Operations Plan (or Continuity of Government) to ensure that US government would be able to continue in catastrophic circumstances. Since 9/11, extremists made various attempts to attack the United States, with varying levels of organization and skill. For example, vigilant passengers aboard a transatlantic flight prevented Richard Reid, in 2001, and Umar Farouk Abdulmutallab, in 2009, from detonating an explosive device. Other terrorist plots have been stopped by federal agencies using new legal powers and investigative tools, sometimes in cooperation with foreign governments.[citation needed] Such thwarted attacks include: The Obama administration promised the closing of the Guantanamo Bay detention camp (GITMO), increased the number of troops in Afghanistan, and promised the withdrawal of its forces from Iraq. Due to congressional opposition, the Obama Administration was unable to close GITMO but brought down its prison population from 242 detainees to 40 detainees. President Trump, during his first administration, signed an executive order keeping Guantanamo Bay's detention camp opened indefinitely, bringing an end to efforts to close it. During his first term, only one detainee was transferred. The Biden Administration, like the former Obama Administration, pledged to close GITMO, but proved unsuccessful too and added million-dollar expansions A total of 25 detainees were transferred during the Biden presidency. After being inaugurated for his second term, President Trump signed a presidential memorandum to begin expansion of the Guantanamo Migrant Operations Center to allow for detainment of up to 30,000 migrants. Transnational actions After 11 September attacks, the United States government commenced a program of illegal "extraordinary rendition", sometimes referred to as "irregular rendition" or "forced rendition", the government-sponsored abduction and extrajudicial transfer of a person from one country to transferee countries, with the consent of transferee countries. The aim of extraordinary rendition is often conducting torture on the detainee that would be difficult to conduct in the US legal environment, a practice known as torture by proxy. Starting in 2002, US government rendered hundreds of illegal combatants for US detention, and transported detainees to US controlled sites as part of an extensive interrogation program that included torture. Extraordinary rendition continued under the Obama administration, with targets being interrogated and subsequently taken to the US for trial. The United Nations considers one nation abducting the citizens of another a crime against humanity. In July 2014 the European Court of Human Rights condemned the government of Poland for participating in CIA extraordinary rendition, ordering Poland to pay restitution to men who had been abducted, taken to a CIA black site in Poland, and tortured. In 2005, The Washington Post and Human Rights Watch (HRW) published revelations concerning kidnapping of detainees by the US Central Intelligence Agency and their transport to "black sites", covert prisons operated by the CIA whose existence is denied by the US government. The European Parliament published a report connecting use of such secret detention Black Sites for detainees kidnapped as part of extraordinary rendition (See the European Parliament's investigation and report). Although some Black Sites have been known to exist inside European Union states, these detention centers violate the European Convention on Human Rights (ECHR) and the UN Convention Against Torture, treaties that all EU member states are bound to follow. The US had ratified the United Nations Convention Against Torture in 1994. According to ABC News two such facilities, in countries mentioned by Human Rights Watch, have been closed following the recent publicity with the CIA relocating the detainees. Almost all of these detainees were tortured as part of the "enhanced interrogation techniques" of the CIA. Despite the closure of these sites, their legacies in certain countries continue to live on and haunt domestic politics. Major American newspapers, such as The Washington Post, have been criticized for deliberately withholding publication of articles reporting locations of Black Sites. The Post defended its decision to suppress this news on the ground that such revelations "could open the US government to legal challenges, particularly in foreign courts, and increase the risk of political condemnation at home and abroad." However, according to Fairness and Accuracy in Reporting "the possibility that illegal, unpopular government actions might be disrupted is not a consequence to be feared, however—it's the whole point of the US First Amendment. ... Without the basic fact of where these prisons are, it's difficult if not impossible for 'legal challenges' or 'political condemnation' to force them to close." FAIR argued that the damage done to the global reputation of the United States by the continued existence of black-site prisons was more dangerous than any threat caused by the exposure of their locations. The complex at Stare Kiejkuty, a Soviet-era compound once used by German intelligence in World War II, is best known as having been the only Russian intelligence training school to operate outside the Soviet Union. Its prominence in the Soviet era suggests that it may have been the facility first identified—but never named—when the Washington Post's Dana Priest revealed the existence of the CIA's secret prison network in November 2005. The journalists who exposed this provided their sources and this information and documents were provided to The Washington Post in 2005. In addition, they also identified such Black Sites are concealed: Former European and US intelligence officials indicate that the secret prisons across the European Union, first identified by the Washington Post, are likely not permanent locations, making them difficult to identify and locate. What some believe was a network of secret prisons was most probably a series of facilities used temporarily by the United States when needed, officials say. Interim "black sites"—secret facilities used for covert activities—can be as small as a room in a government building, which only becomes a black site when a prisoner is brought in for short-term detainment and interrogation. The journalists went on to explain that "Such a site, sources say, would have to be near an airport." The airport in question is the Szczytno-Szymany International Airport. In response to these allegations, former Polish intelligence chief, Zbigniew Siemiatkowski, embarked on a media blitz and claimed that the allegations were "... part of the domestic political battle in the US over who is to succeed current Republican president George W Bush," according to the German news agency Deutsche Presse Agentur. The United States has also been accused of operating "floating prisons" to house and transport those arrested in its war on terror, according to human rights lawyers. They have claimed that the US has tried to conceal the numbers and whereabouts of detainees. Although no credible information to support these assertions has ever come to light, the alleged justification for prison ships is primarily to remove the ability for jihadists to target a fixed location to facilitate the escape of high value targets, commanders, operations chiefs etc. The US government set up the Guantanamo Bay detention camp in 2002, a United States military prison located in Guantanamo Bay Naval Base. President Bush declared that the Geneva Convention, which protects prisoners of war, would not apply to Taliban and al-Qaeda detainees captured in Afghanistan. Since inmates were detained indefinitely without trial and several detainees have allegedly been tortured, this camp is considered to be a major breach of human rights by Amnesty International. The detention camp was set up by the US government on Guantanamo Bay since the military base is not legally domestic US territory and thus was a "legal black hole." Most prisoners of Guantanamo were eventually freed without ever being charged with any crime, and were transferred to other countries. By July 2021, 40 men remain in the prison and almost three-quarters of them have never been criminally charged. They're known as "forever prisoners" and are being detained indefinitely. As of 2025, 15 detainees remain, with three awaiting transfer, nine who have been charged or convicted of war crimes, and three who are held in indefinite law-of-war detention without facing tribunal charges nor being recommended for release. Major terrorist attacks and plots since 9/11 Following the launch of "war on terror" by the United States, several Islamist militant groups as well as militant individuals have launched attacks against the assets of US-led coalition, including in Western countries where active warfare is not taking place. There have also been reports of alleged plots and other planned attacks that were not successful. Casualties There is no widely agreed on figure for the number of people that have been killed so far in the war on terror as the Bush Administration has defined it to include the war in Afghanistan, the war in Iraq, and operations elsewhere. According to Joshua Goldstein, an international relations professor at the American University, the global war on terror has seen fewer war deaths than any other decade in the past century. A 2015 report by the International Physicians for the Prevention of Nuclear War and the Physicians for Social Responsibility and Physicians for Global Survival estimated between 1.3 million to 2 million casualties from the war on terror. A report from September 2021 by Brown University's Watson Institute for International and Public Affairs "Costs of War" project puts the total number of casualties of the war on terror in Iraq, Afghanistan and Pakistan at between 518,000 and 549,000. This number increases to between 897,000 and 929,000 when the wars in Syria, Yemen, and other countries are included. The report estimated that many more may have died from indirect effects of war such as water loss and disease. They also estimated that over 38 million people have been displaced by the post-9/11 wars participated in by the United States in Afghanistan, Pakistan, Iraq, Libya, Syria, Yemen, Somalia, and the Philippines; 26.7 million people have returned home following displacement. The conflict has caused the largest number of forced displacements by any single war since 1900, with the exception of World War II. In a 2023 report, the "Costs of War" project estimated that, as the result of the destruction of infrastructure, economies, public services and the environment, there have been between 3.6 and 3.7 million indirect deaths in the post-9/11 war zones, with the total death toll being 4.5 to 4.6 million and rising. The report defined post-9/11 war zones as conflicts that included significant United States counter-terrorism operations since 9/11, which in addition to the wars in Iraq, Afghanistan and Pakistan, also includes the civil wars in Syria, Yemen, Libya and Somalia. The report derived its estimate of indirect deaths using a calculation from the Geneva Declaration of Secretariat which estimates that for every person directly killed by war, four more die from the indirect consequences of war. The report's author Stephanie Savell stated that in an ideal scenario, the preferable way of quantifying the total death toll would have been by studying excess mortality, or by using on-the-ground researchers in the affected countries. An estimated 7,052 US military combatants, over 8,100 US military contractors and more than 14,800 US-allied coalition troops are estimated to have been killed in the wars as of 2023. The total number of insurgent deaths since the commencement of the war on terror in 2001 is generally estimated as being well into the hundreds of thousands, with hundreds of thousands of others captured or arrested. Some estimates for regional conflicts include the following: In Iraq, some 26,544 insurgents were killed by the American-led coalition and the Iraqi Security Forces from 2003 to 2011. 119,752 suspected insurgents were arrested in Iraq from 2003 to 2007 alone, at which point 18,832 suspected insurgents had been reported killed; applying this same arrested-to-captured ratio to the total number of insurgents killed would equate to approximately 26,500 insurgents killed and 168,000 arrested from 2003 to 2011. At least 4,000 foreign fighters (generally estimated at 10–20% of the insurgency at that point) had been killed by September 2006, according to an official statement from al-Qaeda in Iraq. Insurgent casualties in the 2011–2013 phase of the Iraqi conflict numbered 916 killed, with 3,504 more arrested. From 2014 to the end of 2017, the United States government stated that over 80,000 Islamic State insurgents had been killed by American and allied airstrikes from 2014 to the end of 2017, in both Iraq and Syria. The majority of these strikes occurred within Iraq. ISIL deaths caused by the Iraqi Security Forces in this time are uncertain, but were probably significant. Over 26,000 ISF members were killed fighting ISIL from 2013 to the end of 2017, with ISIL losses likely being of a similar scale. Total casualties in Iraq range from 62,570 to 1,124,000: Insurgent and terrorist deaths in Afghanistan are hard to estimate. Afghan Taliban losses are most likely of a similar scale to Afghan National Army and Police losses; that is around 62,000 from 2001 to the end of 2018. In addition, al-Qaeda's main branch and ISIL's Afghanistan branch are each thought to have lost several thousand killed there since 2001. Total casualties in Afghanistan range from 10,960 and 249,000: Deaths in Iraq and Afghanistan This table shows a comparison of total casualties between the two main theaters of the war on terror—Iraq (since 2003) and Afghanistan (since 2001)—up until August 2021, as conducted by Brown University. 1,467 and 2,334 people were killed in US drone attacks as of 6 May 2011. Tens of thousands have been killed by terrorist attacks and millions have been displaced. The War in Northwest Pakistan resulted in the deaths of 28,900+ militants from 2004 to 2018, with an unknown number captured, per the Pakistani government. The majority of these were killed in engagements with the Pakistan Armed Forces. However, thousands were also killed in American drone strikes. There have been 7,000+ casualties in Somalia. The December 2006 to January 2009 Ethiopian-led intervention in Somalia resulted in the deaths of 6,000 to 8,000 Islamist insurgents, according to the Ethiopian government. The Kenyan Defence Forces claimed another 700+ insurgents killed in their own intervention of October 2011 to May 2012. American drone strikes, air strikes, and special forces ground raids in Somalia killed between 1,220 and 1,366 militants up to July 2019, according to the New American Foundation. American forces (mostly via drone strikes) killed between 846 and 1,609 terrorists in Yemen (mostly AQAP members) up to June 2019, according to a variety of media organizations including the Bureau of Investigative Journalism and the New America Foundation. An Emirati spokesman for the Saudi-led coalition intervening in Yemen claimed that they had killed 1,000 al-Qaeda linked militants and captured 1,500 up to August 2018. Over 1,600 Islamic State fighters (Abu Sayyaf having sworn allegiance to ISIL in 2014) were killed by government forces in the Philippines from 2014 to 2017 alone. From April 2009 to March 2019, Russian military and police (primarily in the North Caucasus) killed 2,329 and captured 2,744 insurgents of the Caucasus Emirate and related groups. (this includes fighting throughout the world): During Operation Inherent Resolve, 95 troops were killed and 227 wounded in action as of 6 May 2020 The United States Department of Veterans Affairs has diagnosed more than 200,000 American veterans with PTSD since 2001. Between 363,939 and 387,072 civilians were killed in post–9/11 wars in Afghanistan, Pakistan, Iraq, Syria, Yemen, and other war zones, according to a 2021 report by the Costs of War Project at Brown University's Watson Institute. Many more may have died due to related effects, including water loss and disease. Costs The war on terror, spanning decades, is a multitrillion-dollar war that cost much more than originally estimated. According to the Costs of War Project at Brown University's Watson Institute, the war on terror will have cost $8 trillion for operations between 2001 and 2022 plus $2.2 trillion in future costs of veterans' care over the next 30 years. Out of this number, $2.313 trillion is for Afghanistan, $2.058 trillion for Iraq and Syria, and $355 billion was spent on other warzones. The remainder was for DHS ($1.1 trillion). According to the Soufan Group in July 2015, the US government was spending $9.4 million per day in operations against ISIL in Syria and Iraq. A March 2011 Congressional report estimated war spending through the fiscal year 2011 at $1.2 trillion, and future spending through 2021 (assuming a reduction to 45,000 troops) at $1.8 trillion. A June 2011 academic report covering additional areas of war spending estimated it through 2011 at $2.7 trillion, and long-term spending at $5.4 trillion including interest.[note 8] In direct spending, the United States Department of Defense reports spending $1.547 trillion from 2001 to February 2020 in war costs in Iraq, Syria, and Afghanistan. Adversary groups have taken an interest in agricultural bioterrorism and this is a continuing concern as of 2022[update]. The US government takes steps to prepare for threats from agricultural pathogens. The National Plant Disease Diagnostic Network (NPDN) coordinates efforts to combat agrowarfare against the US. Criticism Criticism of the war on terror addresses the issues, morality, efficiency, economics, and other questions surrounding the war on terror and made against the phrase itself, calling it a misnomer. The notion of a "war" against "terrorism" has proven highly contentious, with critics charging that it has been exploited by participating governments to pursue long-standing policy/military objectives, including structural Islamophobia, reduce civil liberties, and infringe upon human rights. It is argued that the term war is not appropriate in this context (as in the "war on drugs") since there is no identifiable enemy and that it is unlikely international terrorism can be brought to an end by military means. Other critics, such as Francis Fukuyama, state that "terrorism" is not an enemy but a tactic, and calling it a "war on terror" obscures differences between conflicts such as anti-occupation insurgents and international mujahideen. With a military presence in Iraq and Afghanistan and its associated collateral damage, Shirley Williams posits that this increases resentment and terrorist threats against the West. There is also perceived US hypocrisy, media-induced hysteria, and that differences in foreign and security policy have damaged America's reputation internationally. The campaign has also been rebuked for being a perpetual war with no end-goal and for normalising permanent violence as the status-quo. In addition, Professor Richard Jackson notes how countries like Russia, India, Israel and China adopted the language of the war on terror to describe their own fight against domestic insurgents and dissidents. He argues that "Linking rebels and dissidents at home to the global 'war on terrorism' gives these governments both the freedom to crack down on them without fear of international condemnation, and in some cases, direct military assistance from America". Professor of Law Antony Anghie has asserted that "war on terror" is essentially an imperialist project that constitutes a breach of International law and the United Nations Charter. There has also been systematic cover-ups of war crimes by military officers participating in campaign operations across the world. A public enquiry in the UK published in July 2023 reported that 3 British SAS units were involved in the summary executions of at least 80 civilians during 2010–2013, accompanied by a decades-long coverup at the highest echelons of British special forces. US occupations in Afghanistan and Iraq became heavily unpopular among the American public by the late 2000s. Numerous US military veterans have handed back their service medals—including the Global War on Terrorism Service Medal—in fierce protest rallies denouncing the wars in Afghanistan and Iraq, with many condemning the military campaigns as "illegal occupation" of other countries. Criticism of the war on terror has focused on its morality, efficiency, and cost. The notion of a "war on terror" remain contentious, with critics charging that it has been used to reduce civil liberties and infringe upon human rights, such as controversial actions by the US including surveillance, torture, and extraordinary rendition, and drone strikes that resulted in the deaths of alleged terrorists but also civilians. Many of the US actions were supported by other countries, including the 54 countries that were involved with CIA black sites, or those that assisted with drone strikes. According to a 2021 study by the Costs of War Project, the several post-9/11 wars participated in by the United States in its war against terror have caused the displacement, conservatively calculated, of 38 million people in Afghanistan, Iraq, Libya, Syria, Yemen, Somalia, Philippines and Pakistan; 11.3 million remain displaced. This makes it the war that has caused the largest number of forced displacements since 1900, with the exception of World War II. Another report by the Costs of War Project in 2023 estimates that the wars in these countries have caused a total number of 4.5–4.6 million deaths, including 3.6 million indirect deaths and 906,000–937,000 direct killings. Rather than basing this estimate on detailed data of the concerned countries, the Cost of War report simply multiplied the tallied violent death toll of 906,000–937,000 by four, "by applying the Geneva Declaration Secretariat's average ratio of four indirect for every one direct death." Of the approximately 925,000 violent deaths estimated by the Cost of War project, 542,000 were combatants and 387,000 were civilians. The war costs have risen over $8 trillion for the US Treasury.[d] Critics accuse participating governments of using the "war on terror" to repress minorities or sideline domestic opponents, of fomenting Islamophobia globally, and have criticized negative impacts to health and the environment resulting from it. Critics assert that the term "war" is not appropriate in this context (much like the term "war on drugs") since terror is not an identifiable enemy and it is unlikely that international terrorism can be brought to an end by military means. See also Notes References Further reading External links |
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Contents Animal Animals are multicellular, eukaryotic organisms belonging to the biological kingdom Animalia (/ˌænɪˈmeɪliə/). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor. Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft). They have complex ecologies and interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology, and the study of animal behaviour is known as ethology. The animal kingdom is divided into five major clades, namely Porifera, Ctenophora, Placozoa, Cnidaria and Bilateria. Most living animal species belong to the clade Bilateria, a highly proliferative clade whose members have a bilaterally symmetric and significantly cephalised body plan, and the vast majority of bilaterians belong to two large clades: the protostomes, which includes organisms such as arthropods, molluscs, flatworms, annelids and nematodes; and the deuterostomes, which include echinoderms, hemichordates and chordates, the latter of which contains the vertebrates. The much smaller basal phylum Xenacoelomorpha have an uncertain position within Bilateria. Animals first appeared in the fossil record in the late Cryogenian period and diversified in the subsequent Ediacaran period in what is known as the Avalon explosion. Nearly all modern animal phyla first appeared in the fossil record as marine species during the Cambrian explosion, which began around 539 million years ago (Mya), and most classes during the Ordovician radiation 485.4 Mya. Common to all living animals, 6,331 groups of genes have been identified that may have arisen from a single common ancestor that lived about 650 Mya during the Cryogenian period. Historically, Aristotle divided animals into those with blood and those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa (now synonymous with Animalia) and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between taxa. Humans make use of many other animal species for food (including meat, eggs, and dairy products), for materials (such as leather, fur, and wool), as pets and as working animals for transportation, and services. Dogs, the first domesticated animal, have been used in hunting, in security and in warfare, as have horses, pigeons and birds of prey; while other terrestrial and aquatic animals are hunted for sports, trophies or profits. Non-human animals are also an important cultural element of human evolution, having appeared in cave arts and totems since the earliest times, and are frequently featured in mythology, religion, arts, literature, heraldry, politics, and sports. Etymology The word animal comes from the Latin noun animal of the same meaning, which is itself derived from Latin animalis 'having breath or soul'. The biological definition includes all members of the kingdom Animalia. In colloquial usage, the term animal is often used to refer only to nonhuman animals. The term metazoa is derived from Ancient Greek μετα meta 'after' (in biology, the prefix meta- stands for 'later') and ζῷᾰ zōia 'animals', plural of ζῷον zōion 'animal'. A metazoan is any member of the group Metazoa. Characteristics Animals have several characteristics that they share with other living things. Animals are eukaryotic, multicellular, and aerobic, as are plants and fungi. Unlike plants and algae, which produce their own food, animals cannot produce their own food, a feature they share with fungi. Animals ingest organic material and digest it internally. Animals have structural characteristics that set them apart from all other living things: Typically, there is an internal digestive chamber with either one opening (in Ctenophora, Cnidaria, and flatworms) or two openings (in most bilaterians). Animal development is controlled by Hox genes, which signal the times and places to develop structures such as body segments and limbs. During development, the animal extracellular matrix forms a relatively flexible framework upon which cells can move about and be reorganised into specialised tissues and organs, making the formation of complex structures possible, and allowing cells to be differentiated. The extracellular matrix may be calcified, forming structures such as shells, bones, and spicules. In contrast, the cells of other multicellular organisms (primarily algae, plants, and fungi) are held in place by cell walls, and so develop by progressive growth. Nearly all animals make use of some form of sexual reproduction. They produce haploid gametes by meiosis; the smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova. These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm, also develops between them. These germ layers then differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction generally leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. Some animals are capable of asexual reproduction, which often results in a genetic clone of the parent. This may take place through fragmentation; budding, such as in Hydra and other cnidarians; or parthenogenesis, where fertile eggs are produced without mating, such as in aphids. Ecology Animals are categorised into ecological groups depending on their trophic levels and how they consume organic material. Such groupings include carnivores (further divided into subcategories such as piscivores, insectivores, ovivores, etc.), herbivores (subcategorised into folivores, graminivores, frugivores, granivores, nectarivores, algivores, etc.), omnivores, fungivores, scavengers/detritivores, and parasites. Interactions between animals of each biome form complex food webs within that ecosystem. In carnivorous or omnivorous species, predation is a consumer–resource interaction where the predator feeds on another organism, its prey, who often evolves anti-predator adaptations to avoid being fed upon. Selective pressures imposed on one another lead to an evolutionary arms race between predator and prey, resulting in various antagonistic/competitive coevolutions. Almost all multicellular predators are animals. Some consumers use multiple methods; for example, in parasitoid wasps, the larvae feed on the hosts' living tissues, killing them in the process, but the adults primarily consume nectar from flowers. Other animals may have very specific feeding behaviours, such as hawksbill sea turtles which mainly eat sponges. Most animals rely on biomass and bioenergy produced by plants and phytoplanktons (collectively called producers) through photosynthesis. Herbivores, as primary consumers, eat the plant material directly to digest and absorb the nutrients, while carnivores and other animals on higher trophic levels indirectly acquire the nutrients by eating the herbivores or other animals that have eaten the herbivores. Animals oxidise carbohydrates, lipids, proteins and other biomolecules in cellular respiration, which allows the animal to grow and to sustain basal metabolism and fuel other biological processes such as locomotion. Some benthic animals living close to hydrothermal vents and cold seeps on the dark sea floor consume organic matter produced through chemosynthesis (via oxidising inorganic compounds such as hydrogen sulfide) by archaea and bacteria. Animals originated in the ocean; all extant animal phyla, except for Micrognathozoa and Onychophora, feature at least some marine species. However, several lineages of arthropods begun to colonise land around the same time as land plants, probably between 510 and 471 million years ago, during the Late Cambrian or Early Ordovician. Vertebrates such as the lobe-finned fish Tiktaalik started to move on to land in the late Devonian, about 375 million years ago. Other notable animal groups that colonized land environments are Mollusca, Platyhelmintha, Annelida, Tardigrada, Onychophora, Rotifera, Nematoda. Animals occupy virtually all of earth's habitats and microhabitats, with faunas adapted to salt water, hydrothermal vents, fresh water, hot springs, swamps, forests, pastures, deserts, air, and the interiors of other organisms. Animals are however not particularly heat tolerant; very few of them can survive at constant temperatures above 50 °C (122 °F) or in the most extreme cold deserts of continental Antarctica. The collective global geomorphic influence of animals on the processes shaping the Earth's surface remains largely understudied, with most studies limited to individual species and well-known exemplars. Diversity The blue whale (Balaenoptera musculus) is the largest animal that has ever lived, weighing up to 190 tonnes and measuring up to 33.6 metres (110 ft) long. The largest extant terrestrial animal is the African bush elephant (Loxodonta africana), weighing up to 12.25 tonnes and measuring up to 10.67 metres (35.0 ft) long. The largest terrestrial animals that ever lived were titanosaur sauropod dinosaurs such as Argentinosaurus, which may have weighed as much as 73 tonnes, and Supersaurus which may have reached 39 metres. Several animals are microscopic; some Myxozoa (obligate parasites within the Cnidaria) never grow larger than 20 μm, and one of the smallest species (Myxobolus shekel) is no more than 8.5 μm when fully grown. The following table lists estimated numbers of described extant species for the major animal phyla, along with their principal habitats (terrestrial, fresh water, and marine), and free-living or parasitic ways of life. Species estimates shown here are based on numbers described scientifically; much larger estimates have been calculated based on various means of prediction, and these can vary wildly. For instance, around 25,000–27,000 species of nematodes have been described, while published estimates of the total number of nematode species include 10,000–20,000; 500,000; 10 million; and 100 million. Using patterns within the taxonomic hierarchy, the total number of animal species—including those not yet described—was calculated to be about 7.77 million in 2011.[a] 3,000–6,500 4,000–25,000 Evolutionary origin Evidence of animals is found as long ago as the Cryogenian period. 24-Isopropylcholestane (24-ipc) has been found in rocks from roughly 650 million years ago; it is only produced by sponges and pelagophyte algae. Its likely origin is from sponges based on molecular clock estimates for the origin of 24-ipc production in both groups. Analyses of pelagophyte algae consistently recover a Phanerozoic origin, while analyses of sponges recover a Neoproterozoic origin, consistent with the appearance of 24-ipc in the fossil record. The first body fossils of animals appear in the Ediacaran, represented by forms such as Charnia and Spriggina. It had long been doubted whether these fossils truly represented animals, but the discovery of the animal lipid cholesterol in fossils of Dickinsonia establishes their nature. Animals are thought to have originated under low-oxygen conditions, suggesting that they were capable of living entirely by anaerobic respiration, but as they became specialised for aerobic metabolism they became fully dependent on oxygen in their environments. Many animal phyla first appear in the fossil record during the Cambrian explosion, starting about 539 million years ago, in beds such as the Burgess Shale. Extant phyla in these rocks include molluscs, brachiopods, onychophorans, tardigrades, arthropods, echinoderms and hemichordates, along with numerous now-extinct forms such as the predatory Anomalocaris. The apparent suddenness of the event may however be an artefact of the fossil record, rather than showing that all these animals appeared simultaneously. That view is supported by the discovery of Auroralumina attenboroughii, the earliest known Ediacaran crown-group cnidarian (557–562 mya, some 20 million years before the Cambrian explosion) from Charnwood Forest, England. It is thought to be one of the earliest predators, catching small prey with its nematocysts as modern cnidarians do. Some palaeontologists have suggested that animals appeared much earlier than the Cambrian explosion, possibly as early as 1 billion years ago. Early fossils that might represent animals appear for example in the 665-million-year-old rocks of the Trezona Formation of South Australia. These fossils are interpreted as most probably being early sponges. Trace fossils such as tracks and burrows found in the Tonian period (from 1 gya) may indicate the presence of triploblastic worm-like animals, roughly as large (about 5 mm wide) and complex as earthworms. However, similar tracks are produced by the giant single-celled protist Gromia sphaerica, so the Tonian trace fossils may not indicate early animal evolution. Around the same time, the layered mats of microorganisms called stromatolites decreased in diversity, perhaps due to grazing by newly evolved animals. Objects such as sediment-filled tubes that resemble trace fossils of the burrows of wormlike animals have been found in 1.2 gya rocks in North America, in 1.5 gya rocks in Australia and North America, and in 1.7 gya rocks in Australia. Their interpretation as having an animal origin is disputed, as they might be water-escape or other structures. Phylogeny Animals are monophyletic, meaning they are derived from a common ancestor. Animals are the sister group to the choanoflagellates, with which they form the Choanozoa. Ros-Rocher and colleagues (2021) trace the origins of animals to unicellular ancestors, providing the external phylogeny shown in the cladogram. Uncertainty of relationships is indicated with dashed lines. The animal clade had certainly originated by 650 mya, and may have come into being as much as 800 mya, based on molecular clock evidence for different phyla. Holomycota (inc. fungi) Ichthyosporea Pluriformea Filasterea The relationships at the base of the animal tree have been debated. Other than Ctenophora, the Bilateria and Cnidaria are the only groups with symmetry, and other evidence shows they are closely related. In addition to sponges, Placozoa has no symmetry and was often considered a "missing link" between protists and multicellular animals. The presence of hox genes in Placozoa shows that they were once more complex. The Porifera (sponges) have long been assumed to be sister to the rest of the animals, but there is evidence that the Ctenophora may be in that position. Molecular phylogenetics has supported both the sponge-sister and ctenophore-sister hypotheses. In 2017, Roberto Feuda and colleagues, using amino acid differences, presented both, with the following cladogram for the sponge-sister view that they supported (their ctenophore-sister tree simply interchanging the places of ctenophores and sponges): Porifera Ctenophora Placozoa Cnidaria Bilateria Conversely, a 2023 study by Darrin Schultz and colleagues uses ancient gene linkages to construct the following ctenophore-sister phylogeny: Ctenophora Porifera Placozoa Cnidaria Bilateria Sponges are physically very distinct from other animals, and were long thought to have diverged first, representing the oldest animal phylum and forming a sister clade to all other animals. Despite their morphological dissimilarity with all other animals, genetic evidence suggests sponges may be more closely related to other animals than the comb jellies are. Sponges lack the complex organisation found in most other animal phyla; their cells are differentiated, but in most cases not organised into distinct tissues, unlike all other animals. They typically feed by drawing in water through pores, filtering out small particles of food. The Ctenophora and Cnidaria are radially symmetric and have digestive chambers with a single opening, which serves as both mouth and anus. Animals in both phyla have distinct tissues, but these are not organised into discrete organs. They are diploblastic, having only two main germ layers, ectoderm and endoderm. The tiny placozoans have no permanent digestive chamber and no symmetry; they superficially resemble amoebae. Their phylogeny is poorly defined, and under active research. The remaining animals, the great majority—comprising some 29 phyla and over a million species—form the Bilateria clade, which have a bilaterally symmetric body plan. The Bilateria are triploblastic, with three well-developed germ layers, and their tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and in the Nephrozoa there is an internal body cavity, a coelom or pseudocoelom. These animals have a head end (anterior) and a tail end (posterior), a back (dorsal) surface and a belly (ventral) surface, and a left and a right side. A modern consensus phylogenetic tree for the Bilateria is shown below. Xenacoelomorpha Ambulacraria Chordata Ecdysozoa Spiralia Having a front end means that this part of the body encounters stimuli, such as food, favouring cephalisation, the development of a head with sense organs and a mouth. Many bilaterians have a combination of circular muscles that constrict the body, making it longer, and an opposing set of longitudinal muscles, that shorten the body; these enable soft-bodied animals with a hydrostatic skeleton to move by peristalsis. They also have a gut that extends through the basically cylindrical body from mouth to anus. Many bilaterian phyla have primary larvae which swim with cilia and have an apical organ containing sensory cells. However, over evolutionary time, descendant spaces have evolved which have lost one or more of each of these characteristics. For example, adult echinoderms are radially symmetric (unlike their larvae), while some parasitic worms have extremely simplified body structures. Genetic studies have considerably changed zoologists' understanding of the relationships within the Bilateria. Most appear to belong to two major lineages, the protostomes and the deuterostomes. It is often suggested that the basalmost bilaterians are the Xenacoelomorpha, with all other bilaterians belonging to the subclade Nephrozoa. However, this suggestion has been contested, with other studies finding that xenacoelomorphs are more closely related to Ambulacraria than to other bilaterians. Protostomes and deuterostomes differ in several ways. Early in development, deuterostome embryos undergo radial cleavage during cell division, while many protostomes (the Spiralia) undergo spiral cleavage. Animals from both groups possess a complete digestive tract, but in protostomes the first opening of the embryonic gut develops into the mouth, and the anus forms secondarily. In deuterostomes, the anus forms first while the mouth develops secondarily. Most protostomes have schizocoelous development, where cells simply fill in the interior of the gastrula to form the mesoderm. In deuterostomes, the mesoderm forms by enterocoelic pouching, through invagination of the endoderm. The main deuterostome taxa are the Ambulacraria and the Chordata. Ambulacraria are exclusively marine and include acorn worms, starfish, sea urchins, and sea cucumbers. The chordates are dominated by the vertebrates (animals with backbones), which consist of fishes, amphibians, reptiles, birds, and mammals. The protostomes include the Ecdysozoa, named after their shared trait of ecdysis, growth by moulting, Among the largest ecdysozoan phyla are the arthropods and the nematodes. The rest of the protostomes are in the Spiralia, named for their pattern of developing by spiral cleavage in the early embryo. Major spiralian phyla include the annelids and molluscs. History of classification In the classical era, Aristotle divided animals,[d] based on his own observations, into those with blood (roughly, the vertebrates) and those without. The animals were then arranged on a scale from man (with blood, two legs, rational soul) down through the live-bearing tetrapods (with blood, four legs, sensitive soul) and other groups such as crustaceans (no blood, many legs, sensitive soul) down to spontaneously generating creatures like sponges (no blood, no legs, vegetable soul). Aristotle was uncertain whether sponges were animals, which in his system ought to have sensation, appetite, and locomotion, or plants, which did not: he knew that sponges could sense touch and would contract if about to be pulled off their rocks, but that they were rooted like plants and never moved about. In 1758, Carl Linnaeus created the first hierarchical classification in his Systema Naturae. In his original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then, the last four have all been subsumed into a single phylum, the Chordata, while his Insecta (which included the crustaceans and arachnids) and Vermes have been renamed or broken up. The process was begun in 1793 by Jean-Baptiste de Lamarck, who called the Vermes une espèce de chaos ('a chaotic mess')[e] and split the group into three new phyla: worms, echinoderms, and polyps (which contained corals and jellyfish). By 1809, in his Philosophie Zoologique, Lamarck had created nine phyla apart from vertebrates (where he still had four phyla: mammals, birds, reptiles, and fish) and molluscs, namely cirripedes, annelids, crustaceans, arachnids, insects, worms, radiates, polyps, and infusorians. In his 1817 Le Règne Animal, Georges Cuvier used comparative anatomy to group the animals into four embranchements ('branches' with different body plans, roughly corresponding to phyla), namely vertebrates, molluscs, articulated animals (arthropods and annelids), and zoophytes (radiata) (echinoderms, cnidaria and other forms). This division into four was followed by the embryologist Karl Ernst von Baer in 1828, the zoologist Louis Agassiz in 1857, and the comparative anatomist Richard Owen in 1860. In 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms: Metazoa (multicellular animals, with five phyla: coelenterates, echinoderms, articulates, molluscs, and vertebrates) and Protozoa (single-celled animals), including a sixth animal phylum, sponges. The protozoa were later moved to the former kingdom Protista, leaving only the Metazoa as a synonym of Animalia. In human culture The human population exploits a large number of other animal species for food, both of domesticated livestock species in animal husbandry and, mainly at sea, by hunting wild species. Marine fish of many species are caught commercially for food. A smaller number of species are farmed commercially. Humans and their livestock make up more than 90% of the biomass of all terrestrial vertebrates, and almost as much as all insects combined. Invertebrates including cephalopods, crustaceans, insects—principally bees and silkworms—and bivalve or gastropod molluscs are hunted or farmed for food, fibres. Chickens, cattle, sheep, pigs, and other animals are raised as livestock for meat across the world. Animal fibres such as wool and silk are used to make textiles, while animal sinews have been used as lashings and bindings, and leather is widely used to make shoes and other items. Animals have been hunted and farmed for their fur to make items such as coats and hats. Dyestuffs including carmine (cochineal), shellac, and kermes have been made from the bodies of insects. Working animals including cattle and horses have been used for work and transport from the first days of agriculture. Animals such as the fruit fly Drosophila melanogaster serve a major role in science as experimental models. Animals have been used to create vaccines since their discovery in the 18th century. Some medicines such as the cancer drug trabectedin are based on toxins or other molecules of animal origin. People have used hunting dogs to help chase down and retrieve animals, and birds of prey to catch birds and mammals, while tethered cormorants have been used to catch fish. Poison dart frogs have been used to poison the tips of blowpipe darts. A wide variety of animals are kept as pets, from invertebrates such as tarantulas, octopuses, and praying mantises, reptiles such as snakes and chameleons, and birds including canaries, parakeets, and parrots all finding a place. However, the most kept pet species are mammals, namely dogs, cats, and rabbits. There is a tension between the role of animals as companions to humans, and their existence as individuals with rights of their own. A wide variety of terrestrial and aquatic animals are hunted for sport. The signs of the Western and Chinese zodiacs are based on animals. In China and Japan, the butterfly has been seen as the personification of a person's soul, and in classical representation the butterfly is also the symbol of the soul. Animals have been the subjects of art from the earliest times, both historical, as in ancient Egypt, and prehistoric, as in the cave paintings at Lascaux. Major animal paintings include Albrecht Dürer's 1515 The Rhinoceros, and George Stubbs's c. 1762 horse portrait Whistlejacket. Insects, birds and mammals play roles in literature and film, such as in giant bug movies. Animals including insects and mammals feature in mythology and religion. The scarab beetle was sacred in ancient Egypt, and the cow is sacred in Hinduism. Among other mammals, deer, horses, lions, bats, bears, and wolves are the subjects of myths and worship. See also Notes References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Antlia] | [TOKENS: 2548] |
Contents Antlia Antlia (/ˈæntliə/; from Ancient Greek ἀντλία) is a constellation in the Southern Celestial Hemisphere. Its name means "pump" in Latin and Greek; it represents an air pump. Originally Antlia Pneumatica, the constellation was established by Nicolas-Louis de Lacaille in the 18th century. Its non-specific (single-word) name, already in limited use, was preferred by John Herschel then welcomed by the astronomic community which officially accepted this. North of stars forming some of the sails of the ship Argo Navis (the constellation Vela), Antlia is completely visible from latitudes south of 49 degrees north. Antlia is a faint constellation; its brightest star is Alpha Antliae, an orange giant that is a suspected variable star, ranging between apparent magnitudes 4.22 and 4.29. S Antliae is an eclipsing binary star system, changing in brightness as one star passes in front of the other. Sharing a common envelope, the stars are so close they will one day merge to form a single star. Two star systems with known exoplanets, HD 93083 and WASP-66, lie within Antlia, as do NGC 2997, a spiral galaxy, and the Antlia Dwarf Galaxy. History The French astronomer Nicolas-Louis de Lacaille first described the constellation in French as la Machine Pneumatique (the Pneumatic Machine) in 1751–52, commemorating the air pump invented by the French physicist Denis Papin. De Lacaille had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope, devising fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. He named all but one in honour of instruments that symbolised the Age of Enlightenment.[a] Lacaille depicted Antlia as a single-cylinder vacuum pump used in Papin's initial experiments, while German astronomer Johann Bode chose the more advanced double-cylinder version. Lacaille Latinised the name to Antlia pneumatica on his 1763 chart. English astronomer John Herschel proposed shrinking the name to one word in 1844, noting that Lacaille himself had abbreviated his constellations thus on occasion. This was universally adopted. The International Astronomical Union adopted it as one of the 88 modern constellations in 1922. Although visible to the Ancient Greeks, Antlia's stars were too faint to have been commonly recognised as a figurative object, or part of one, in ancient asterisms. The stars that now comprise Antlia are in a zone of the sky associated with the asterism/old constellation Argo Navis, the ship, the Argo, of the Argonauts, in its latter centuries. This, due to its immense size, was split into hull, poop deck and sails by Lacaille in 1763. Ridpath reports that due to their faintness, the stars of Antlia did not make up part of the classical depiction of Argo Navis. Chinese astronomers were able to view what is modern Antlia from their latitudes, and incorporated its stars into two different constellations. Several stars in the southern part of Antlia were a portion of "Dong'ou", which represented an area in southern China. Furthermore, Epsilon, Eta, and Theta Antliae were incorporated into the celestial temple, which also contained stars from modern Pyxis. Characteristics Covering 238.9 square degrees and hence 0.579% of the sky, Antlia ranks 62nd of the 88 modern constellations by area. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 49°N.[b] Hydra the sea snake runs along the length of its northern border, while Pyxis the compass, Vela the sails, and Centaurus the centaur line it to the west, south and east respectively. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union, is "Ant". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930,[c] are defined by a polygon with an east side, south side and ten other sides (facing the two other cardinal compass points) (illustrated in infobox at top-right). In the equatorial coordinate system, the right ascension coordinates of these borders lie between 09h 26.5m and 11h 05.6m , while the declination coordinates are between −24.54° and −40.42°. Features Lacaille gave nine stars Bayer designations, labelling them Alpha through to Theta, combining two stars next to each other as Zeta. Gould later added a tenth, Iota Antliae. Beta and Gamma Antliae (now HR 4339 and HD 90156) ended up in the neighbouring constellation Hydra once the constellation boundaries were delineated in 1930. Within the constellation's borders, there are 42 stars brighter than or equal to apparent magnitude 6.5.[d] The constellation's two brightest stars—Alpha and Epsilon Antliae—shine with a reddish tinge. Alpha is an orange giant of spectral type K4III that is a suspected variable star, ranging between apparent magnitudes 4.22 and 4.29. It is located 320 ± 10 light-years away from Earth. Estimated to be shining with around 480 to 555 times the luminosity of the Sun, it is most likely an ageing star that is brightening and on its way to becoming a Mira variable star, having converted all its core fuel into carbon. Located 590 ± 30 light-years from Earth, Epsilon Antliae is an evolved orange giant star of spectral type K3 IIIa, that has swollen to have a diameter about 69 times that of the Sun, and a luminosity of around 1279 Suns. It is slightly variable. At the other end of Antlia, Iota Antliae is likewise an orange giant of spectral type K1 III. It is 202 ± 2 light-years distant. Located near Alpha is Delta Antliae, a binary star, 450 ± 10 light-years distant from Earth. The primary is a blue-white main sequence star of spectral type B9.5V and magnitude 5.6, and the secondary is a yellow-white main sequence star of spectral type F9Ve and magnitude 9.6. Zeta Antliae is a wide optical double star. The brighter star—Zeta1 Antliae—is 410 ± 40 light-years distant and has a magnitude of 5.74, though it is a true binary star system composed of two white main sequence stars of magnitudes 6.20 and 7.01 that are separated by 8.042 arcseconds. The fainter star—Zeta2 Antliae—is 386 ± 5 light-years distant and of magnitude 5.9. Eta Antliae is another double composed of a yellow white star of spectral type F1V and magnitude 5.31, with a companion of magnitude 11.3. Theta Antliae is likewise double, most likely composed of an A-type main sequence star and a yellow giant. S Antliae is an eclipsing binary star system that varies in apparent magnitude from 6.27 to 6.83 over a period of 15.6 hours. The system is classed as a W Ursae Majoris variable—the primary is hotter than the secondary and the drop in magnitude is caused by the latter passing in front of the former. Calculating the properties of the component stars from the orbital period indicates that the primary star has a mass 1.94 times and a diameter 2.026 times that of the Sun, and the secondary has a mass 0.76 times and a diameter 1.322 times that of the Sun. The two stars have similar luminosity and spectral type as they have a common envelope and share stellar material. The system is thought to be around 5–6 billion years old. The two stars will eventually merge to form a single fast-spinning star. T Antliae is a yellow-white supergiant of spectral type F6Iab and Classical Cepheid variable ranging between magnitude 8.88 and 9.82 over 5.9 days. U Antliae is a red C-type carbon star and is an irregular variable that ranges between magnitudes 5.27 and 6.04. At 910 ± 50 light-years distant, it is around 5819 times as luminous as the Sun. BF Antliae is a Delta Scuti variable that varies by 0.01 of a magnitude. HR 4049, also known as AG Antliae, is an unusual hot variable ageing star of spectral type B9.5Ib-II. It is undergoing intense loss of mass and is a unique variable that does not belong to any class of known variable star, ranging between magnitudes 5.29 and 5.83 with a period of 429 days. It is around 6000 light-years away from Earth. UX Antliae is an R Coronae Borealis variable with a baseline apparent magnitude of around 11.85, with irregular dimmings down to below magnitude 18.0. A luminous and remote star, it is a supergiant with a spectrum resembling that of a yellow-white F-type star but it has almost no hydrogen. HD 93083 is an orange dwarf star of spectral type K3V that is smaller and cooler than the Sun. It has a planet that was discovered by the radial velocity method with the HARPS spectrograph in 2005. About as massive as Saturn, the planet orbits its star with a period of 143 days at a mean distance of 0.477 AU. WASP-66 is a sunlike star of spectral type F4V. A planet with 2.3 times the mass of Jupiter orbits it every 4 days, discovered by the transit method in 2012. DEN 1048-3956 is a brown dwarf of spectral type M8 located around 13 light-years distant from Earth. At magnitude 17 it is much too faint to be seen with the unaided eye. It has a surface temperature of about 2500 K. Two powerful flares lasting 4–5 minutes each were detected in 2002. 2MASS 0939-2448 is a system of two cool and faint brown dwarfs, probably with effective temperatures of about 500 and 700 K and masses of about 25 and 40 times that of Jupiter, though it is also possible that both objects have temperatures of 600 K and 30 Jupiter masses. Antlia contains many faint galaxies, the brightest of which is NGC 2997 at magnitude 10.6. It is a loosely wound face-on spiral galaxy of type Sc. Though nondescript in most amateur telescopes, it presents bright clusters of young stars and many dark dust lanes in photographs. Discovered in 1997, the Antlia Dwarf is a 14.8m dwarf spheroidal galaxy that belongs to the Local Group of galaxies. In 2018 the discovery was announced of a very low surface brightness galaxy near Epsilon Antliae, Antlia 2, which is a satellite galaxy of the Milky Way. The Antlia Cluster, also known as Abell S0636, is a cluster of galaxies located in the Hydra–Centaurus Supercluster. It is the third nearest to the Local Group after the Virgo Cluster and the Fornax Cluster. The cluster's distance from earth is 40.5 to 40.9 Mpc (132.1 to 133.4 Mly) Located in the southeastern corner of the constellation, it boasts the giant elliptical galaxies NGC 3268 and NGC 3258 as the main members of a southern and northern subgroup respectively, and contains around 234 galaxies in total. Antlia is home to the huge Antlia Supernova Remnant, one of the largest supernova remnants in the sky. Notes References External links |
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