Split (1)

train · 96.9k rows

text stringlengths 0 473k

[SOURCE: https://en.wikipedia.org/wiki/Genius_(mathematics_software)] \| [TOKENS: 272]
Contents Genius (mathematics software) Genius (also known as the Genius Math Tool) is a free open-source numerical computing environment and programming language, similar in some aspects to MATLAB, GNU Octave, Mathematica and Maple. Genius is aimed at mathematical experimentation rather than computationally intensive tasks. It is also very useful as just a calculator. The programming language is called GEL and aims to have a mathematically friendly syntax. The software comes with a command-line interface and a GUI, which uses the GTK+ libraries. The graphical version supports both 2D and 3D plotting. The graphical version includes a set of tutorials originally aimed at in class demonstrations. History Genius was the original calculator for the GNOME project started in 1997, but was split into a separate project soon after the 0.13 release of GNOME in 1998. Because of this ancestry, it was also known as Genius Calculator or GNOME Genius. There was an attempt to merge Genius and the Dr. Geo interactive geometry software, but this merge never materialized. Version 1.0 was released in 2007 almost 10 years after the initial release. Example GEL source code Here is a sample definition of a function calculating the factorial recursively GEL contains primitives for writing the product iteratively and hence we can get the following iterative version See also Notes and references
========================================

[SOURCE: https://www.ynet.co.il/economy/article/s1pbxixubg] \| [TOKENS: 377]
מהערים היקרות בארה"ב - והישראלים ממשיכים להגיע: מה מושך כל כך בבוסטון הקהילה הישראלית בבוסטון שונה מקהילות אחרות בארה"ב: היא מורכבת בעיקר ‏מאקדמאים ואנשי הייטק, וכמעט אין בה קבלנים או נותני שירותים. "העולם השתנה, אנו חיים בגלובליות וללא ‏גבולות. במקום להיות שיפוטיים ולהגיד שאנשים יורדים מהארץ, צריך לטפח את הקשר בין המדינה ‏לקהילה בחו"ל"‏ \| חלום אמריקני: מסע אל הקהילות הישראליות בארה"ב, פרק שישי
========================================

[SOURCE: https://en.wikipedia.org/wiki/Jund_al-Urdunn] \| [TOKENS: 556]
Contents Jund al-Urdunn Jund al-Urdunn (Arabic: جُـنْـد الْأُرْدُنّ, translation: "The military district of Jordan") was one of the five districts of Bilad al-Sham (Islamic Syria) during the early Islamic period. It was established under the Rashidun and its capital was Tiberias throughout its rule by the Umayyad and Abbasid caliphates. It encompassed southern Mount Lebanon, the Galilee, the southern Hauran, the Golan Heights, and most of the eastern Jordan Valley (especially in the north). Subdistricts and major towns The 10th-century geographer Ibn al-Faqih held that besides its capital at Tiberias, the Urdunn's chief districts (qura) were Samaria (al-Samira in Arabic), i.e. Nablus, Beisan, Qadas, Pella (Fahl in Arabic), Jerash, Acre (Akka in Arabic), and Tyre (Sur in Arabic). The geographer al-Muqaddasi (d. 985) notes that the principal towns of the district were its capital Tiberias, Qadas, Tyre, Acre, Faradiyya, Kabul, Beisan, Lajjun and Adhri'at. The 13th-century geographer Yaqut al-Hamawi counted the quras of Urdunn as Tiberias, Beisan, Acre, Beit Ras, Jadar (Jaydur, area adjacent to the east of the Golan Heights), Tyre and Saffuriya. The geographers Ibn Hawqal (d. c. 978) and Estakhri (d. 957) noted the Ghawr (Jordan Valley) district, the low-lying area along the Jordan River between Lake Tiberias to the Dead Sea, with its capital at Jericho (Ariha in Arabic), was administratively subordinate to Urdunn. The geographer al-Ya'qubi (d. 892) held that the Ghawr was subordinate to Jund Dimashq. Population The Galilee was referred to as "Jabal al-Jalil" by the 9th century Arab geographer Ya'qubi (d. 891), who noted that its residents were Banu Amilah Arabs. Michael Ehrlich asserts that while the majority of people in the Western Galilee and Lower Galilee probably embraced Islam during the early Islamic period, the Islamization process in the Eastern Galilee took a little longer and lasted until the Mamluk period. Governors See also References Bibliography
========================================

[SOURCE: https://en.wikipedia.org/wiki/Television_licensing_in_the_United_Kingdom_(historical)#Number_of_licences_issued] \| [TOKENS: 606]
Contents History of television licensing in the United Kingdom The first broadcasting receiving licence was introduced in 1904 to cover the reception of radio broadcasts. It is paid annually. Historical timeline The introduction of receiving licences was implemented by the General Post Office (GPO) using powers within the Wireless Telegraphy Act 1904. Section 2 of the act allowed the Postmaster General to charge for the issuing of licenses permitting the "experimental" receipt of radio transmissions. The Wireless Telegraphy Act 1904 was introduced as a temporary measure, and required annual extensions by Parliament until replaced by the Wireless Telegraphy Act 1949. A return made to Parliament in June 1906 showed that in the first two years of operation only sixty eight receiving licences were issued. By April 1913 the number had, according to figures then released by the GPO, risen to two thousand. The First World War resulted in all licence holders receiving notice on 1 August 1914 from the Postmaster General that they were required to dismantle their receiving equipment, their broadcast receiving licences having been suspended. In 1920, the Post Office licensed a small number of experimental transmitting stations, making general broadcasts.[citation needed] At the instigation of the Post Office, the British Broadcasting Company was established in October 1922 by a group of radio manufacturers to produce radio programmes for the users of their products. Initially the broadcasts were funded by the sale of radio receiving sets, and carried sponsored programmes. As part of the agreement with the Post Office, the Postmaster General started to apply a condition to broadcast receiving licences that the equipment used be "Type Approved by Postmaster General" and marked with the BBC logo. Initially, the fee for receiving licences was 10 shillings, and remained at that rate until after the Second World War. With the forming of the public British Broadcasting Corporation in 1927, the Post Office dedicated nearly the entirety of licence fee income to the funding of the BBC. The standard broadcast receiving licences covered reception of the BBC's 405-line television service between November 1936 and September 1939 at no additional cost. The outbreak of the Second World War in 1939 led to the suspension of television broadcasts in the UK. The television licence was introduced in June 1946 to coincide with the post-war resumption of the BBC service the same month. Television licences always included a licence to receive radio broadcasts. From 1971, only the reception of television transmissions required a licence, and radio-only licences ceased to be issued. The colour television licence (actually a "colour supplementary fee" of £5 on top of the existing monochrome licence) was introduced in 1968, following the commencement of BBC2 colour transmissions the previous July. Changing cost of the licence fee Cost of a colour TV licence Cost of a colour TV licence (inflation adjusted) Number of licences issued The number of licences on issue at 31 March or 1 April by year is as follows: See also References Sources External links
========================================

[SOURCE: https://en.wikipedia.org/wiki/Internet#cite_ref-131] \| [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
========================================

[SOURCE: https://en.wikipedia.org/wiki/Extraterrestrial_life#cite_ref-59] \| [TOKENS: 11349]
Contents Extraterrestrial life Extraterrestrial life, or alien life (colloquially aliens), is life that originates from another world rather than on Earth. No extraterrestrial life has yet been scientifically or conclusively detected. Such life might range from simple forms such as prokaryotes to intelligent beings, possibly bringing forth civilizations that might be far more, or far less, advanced than humans. The Drake equation speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life is known as astrobiology. Speculation about inhabited worlds beyond Earth dates back to antiquity. Early Christian writers, including Augustine, discussed ideas from thinkers like Democritus and Epicurus about countless worlds in the vast universe. Pre-modern writers typically assumed extraterrestrial "worlds" were inhabited by living beings. William Vorilong, in the 15th century, acknowledged the possibility Jesus could have visited extraterrestrial worlds to redeem their inhabitants.: 26 In 1440, Nicholas of Cusa suggested Earth is a "brilliant star"; he theorized that all celestial bodies, even the Sun, could host life. Descartes wrote that there were no means to prove the stars were not inhabited by "intelligent creatures", but their existence was a matter of speculation.: 67 In comparison to the life-abundant Earth, the vast majority of intrasolar and extrasolar planets and moons have harsh surface conditions and disparate atmospheric chemistry, or lack an atmosphere. However, there are many extreme and chemically harsh ecosystems on Earth that do support forms of life and are often hypothesized to be the origin of life on Earth. Examples include life surrounding hydrothermal vents, acidic hot springs, and volcanic lakes, as well as halophiles and the deep biosphere. Since the mid-20th century, researchers have searched for extraterrestrial life and intelligence. Solar system studies focus on Venus, Mars, Europa, and Titan, while exoplanet discoveries now total 6,022 confirmed planets in 4,490 systems as of October 2025. Depending on the category of search, methods range from analysis of telescope and specimen data to radios used to detect and transmit interstellar communication. Interstellar travel remains largely hypothetical, with only the Voyager 1 and Voyager 2 probes confirmed to have entered the interstellar medium. The concept of extraterrestrial life, especially intelligent life, has greatly influenced culture and fiction. A key debate centers on contacting extraterrestrial intelligence: some advocate active attempts, while others warn it could be risky, given human history of exploiting other societies. Context Initially, after the Big Bang, the universe was too hot to allow life. It is estimated that the temperature of the universe was around 10 billion Kelvin at the one-second mark. Roughly 15 million years later, it cooled to temperate levels, though the elements of organic life were yet nonexistent. The only freely available elements at that point were hydrogen and helium. Carbon and oxygen (and later, water) would not appear until 50 million years later, created through stellar fusion. At that point, the difficulty for life to appear was not the temperature, but the scarcity of free heavy elements. Planetary systems emerged, and the first organic compounds may have formed in the protoplanetary disk of dust grains that would eventually create rocky planets like Earth. Although Earth was in a molten state after its birth and may have burned any organics that fell on it, it would have been more receptive once it cooled down. Once the right conditions on Earth were met, life started by a chemical process known as abiogenesis. Alternatively, life may have formed less frequently, then spread—by meteoroids, for example—between habitable planets in a process called panspermia. During most of its stellar evolution, stars combine hydrogen nuclei to make helium nuclei by stellar fusion, and the comparatively lighter weight of helium allows the star to release the extra energy. The process continues until the star uses all of its available fuel, with the speed of consumption being related to the size of the star. During its last stages, stars start combining helium nuclei to form carbon nuclei. The larger stars can further combine carbon nuclei to create oxygen and silicon, oxygen into neon and sulfur, and so on until iron. Ultimately, the star blows much of its content back into the stellar medium, where it would join clouds that would eventually become new generations of stars and planets. Many of those materials are the raw components of life on Earth. As this process takes place in all the universe, said materials are ubiquitous in the cosmos and not a rarity from the Solar System. Earth is a planet in the Solar System, a planetary system formed by a star at the center, the Sun, and the objects that orbit it: other planets, moons, asteroids, and comets. The sun is part of the Milky Way, a galaxy. The Milky Way is part of the Local Group, a galaxy group that is in turn part of the Laniakea Supercluster. The universe is composed of all similar structures in existence. The immense distances between celestial objects are a difficulty for studying extraterrestrial life. So far, humans have only set foot on the Moon and sent robotic probes to other planets and moons in the Solar System. Although probes can withstand conditions that may be lethal to humans, the distances cause time delays: the New Horizons took nine years after launch to reach Pluto. No probe has ever reached extrasolar planetary systems. The Voyager 2 left the Solar System at a speed of 50,000 kilometers per hour; if it headed towards the Alpha Centauri system, the closest one to Earth at 4.4 light years, it would reach it in 100,000 years. Under current technology, such systems can only be studied by telescopes, which have limitations. It is estimated that dark matter has a larger amount of combined matter than stars and gas clouds, but as it plays no role in the stellar evolution of stars and planets, it is usually not taken into account by astrobiology. There is an area around a star, the circumstellar habitable zone or "Goldilocks zone", wherein water may be at the right temperature to exist in liquid form at a planetary surface. This area is neither too close to the star, where water would become steam, nor too far away, where water would be frozen as ice. However, although useful as an approximation, planetary habitability is complex and defined by several factors. Being in the habitable zone is not enough for a planet to be habitable, not even to actually have such liquid water. Venus is located in the solar system's habitable zone, but does not have liquid water because of the conditions of its atmosphere. Jovian planets or gas giants are not considered habitable even if they orbit close enough to their stars as hot Jupiters, due to crushing atmospheric pressures. The actual distances for the habitable zones vary according to the type of star, and even the solar activity of each specific star influences the local habitability. The type of star also defines the time the habitable zone will exist, as its presence and limits will change along with the star's stellar evolution. The Big Bang occurred 13.8 billion years ago, the Solar System was formed 4.6 billion years ago, and the first hominids appeared 6 million years ago. Life on other planets may have started, evolved, given birth to extraterrestrial intelligences, and perhaps even faced a planetary extinction event millions or billions of years ago. When considered from a cosmic perspective, the brief times of existence of Earth's species may suggest that extraterrestrial life may be equally fleeting under such a scale. During a period of about 7 million years, from about 10 to 17 million years after the Big Bang, the background temperature was between 373 and 273 K (100 and 0 °C; 212 and 32 °F), allowing the possibility of liquid water if any planets existed. Avi Loeb (2014) speculated that primitive life might in principle have appeared during this window, which he called "the Habitable Epoch of the Early Universe". Life on Earth is quite ubiquitous across the planet and has adapted over time to almost all the available environments in it, extremophiles and the deep biosphere thrive at even the most hostile ones. As a result, it is inferred that life in other celestial bodies may be equally adaptive. However, the origin of life is unrelated to its ease of adaptation and may have stricter requirements. A celestial body may not have any life on it, even if it were habitable. Likelihood of existence Life in the cosmos beyond Earth has been observed. The hypothesis of ubiquitous extraterrestrial life relies on three main ideas. The first one, the size of the universe, allows for plenty of planets to have a similar habitability to Earth, and the age of the universe gives enough time for a long process analog to the history of Earth to happen there. The second is that the substances that make life, such as carbon and water, are ubiquitous in the universe. The third is that the physical laws are universal, which means that the forces that would facilitate or prevent the existence of life would be the same ones as on Earth. According to this argument, made by scientists such as Carl Sagan and Stephen Hawking, it would be improbable for life not to exist somewhere else other than Earth. This argument is embodied in the Copernican principle, which states that Earth does not occupy a unique position in the Universe, and the mediocrity principle, which states that there is nothing special about life on Earth. Other authors consider instead that life in the cosmos, or at least multicellular life, may actually be rare. The Rare Earth hypothesis maintains that life on Earth is possible because of a series of factors that range from the location in the galaxy and the configuration of the Solar System to local characteristics of the planet, and that it is unlikely that another planet simultaneously meets all such requirements. The proponents of this hypothesis consider that very little evidence suggests the existence of extraterrestrial life and that, at this point, it is just a desired result and not a reasonable scientific explanation for any gathered data. In 1961, astronomer and astrophysicist Frank Drake devised the Drake equation as a way to stimulate scientific dialogue at a meeting on the search for extraterrestrial intelligence (SETI). The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy. The Drake equation is:: xix where: and Drake's proposed estimates are as follows, but numbers on the right side of the equation are agreed as speculative and open to substitution: 10,000 = 5 ⋅ 0.5 ⋅ 2 ⋅ 1 ⋅ 0.2 ⋅ 1 ⋅ 10,000 {\displaystyle 10{,}000=5\cdot 0.5\cdot 2\cdot 1\cdot 0.2\cdot 1\cdot 10{,}000} [better source needed] The Drake equation has proved controversial since, although it is written as a math equation, none of its values were known at the time. Although some values may eventually be measured, others are based on social sciences and are not knowable by their very nature. This does not allow one to make noteworthy conclusions from the equation. Based on observations from the Hubble Space Telescope, there are nearly 2 trillion galaxies in the observable universe. It is estimated that at least ten percent of all Sun-like stars have a system of planets. In other words, there are 6.25×1018 stars with planets orbiting them in the observable universe. Even if it is assumed that only one out of a billion of these stars has planets supporting life, there would be some 6.25 billion life-supporting planetary systems in the observable universe. A 2013 study based on results from the Kepler spacecraft estimated that the Milky Way contains at least as many planets as it does stars, resulting in 100–400 billion exoplanets. The Nebular hypothesis that explains the formation of the Solar System and other planetary systems would suggest that those can have several configurations, and not all of them may have rocky planets within the habitable zone. The apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilisations and the lack of evidence for such civilisations is known as the Fermi paradox. Dennis W. Sciama claimed that life's existence in the universe depends on various fundamental constants. Zhi-Wei Wang and Samuel L. Braunstein suggest that a random universe capable of supporting life is likely to be just barely able to do so, giving a potential explanation to the Fermi paradox. Biochemical basis If extraterrestrial life exists, it could range from simple microorganisms and multicellular organisms similar to animals or plants, to complex alien intelligences akin to humans. When scientists talk about extraterrestrial life, they consider all those types. Although it is possible that extraterrestrial life may have other configurations, scientists use the hierarchy of lifeforms from Earth for simplicity, as it is the only one known to exist. The first basic requirement for life is an environment with non-equilibrium thermodynamics, which means that the thermodynamic equilibrium must be broken by a source of energy. The traditional sources of energy in the cosmos are the stars, such as for life on Earth, which depends on the energy of the sun. However, there are other alternative energy sources, such as volcanoes, plate tectonics, and hydrothermal vents. There are ecosystems on Earth in deep areas of the ocean that do not receive sunlight, and take energy from black smokers instead. Magnetic fields and radioactivity have also been proposed as sources of energy, although they would be less efficient ones. Life on Earth requires water in a liquid state as a solvent in which biochemical reactions take place. It is highly unlikely that an abiogenesis process can start within a gaseous or solid medium: the atom speeds, either too fast or too slow, make it difficult for specific ones to meet and start chemical reactions. A liquid medium also allows the transport of nutrients and substances required for metabolism. Sufficient quantities of carbon and other elements, along with water, might enable the formation of living organisms on terrestrial planets with a chemical make-up and temperature range similar to that of Earth. Life based on ammonia rather than water has been suggested as an alternative, though this solvent appears less suitable than water. It is also conceivable that there are forms of life whose solvent is a liquid hydrocarbon, such as methane, ethane or propane. Another unknown aspect of potential extraterrestrial life would be the chemical elements that would compose it. Life on Earth is largely composed of carbon, but there could be other hypothetical types of biochemistry. A replacement for carbon would need to be able to create complex molecules, store information required for evolution, and be freely available in the medium. To create DNA, RNA, or a close analog, such an element should be able to bind its atoms with many others, creating complex and stable molecules. It should be able to create at least three covalent bonds: two for making long strings and at least a third to add new links and allow for diverse information. Only nine elements meet this requirement: boron, nitrogen, phosphorus, arsenic, antimony (three bonds), carbon, silicon, germanium and tin (four bonds). As for abundance, carbon, nitrogen, and silicon are the most abundant ones in the universe, far more than the others. On Earth's crust the most abundant of those elements is silicon, in the Hydrosphere it is carbon and in the atmosphere, it is carbon and nitrogen. Silicon, however, has disadvantages over carbon. The molecules formed with silicon atoms are less stable, and more vulnerable to acids, oxygen, and light. An ecosystem of silicon-based lifeforms would require very low temperatures, high atmospheric pressure, an atmosphere devoid of oxygen, and a solvent other than water. The low temperatures required would add an extra problem, the difficulty to kickstart a process of abiogenesis to create life in the first place. Norman Horowitz, head of the Jet Propulsion Laboratory bioscience section for the Mariner and Viking missions from 1965 to 1976 considered that the great versatility of the carbon atom makes it the element most likely to provide solutions, even exotic solutions, to the problems of survival of life on other planets. However, he also considered that the conditions found on Mars were incompatible with carbon based life. Even if extraterrestrial life is based on carbon and uses water as a solvent, like Earth life, it may still have a radically different biochemistry. Life is generally considered to be a product of natural selection. It has been proposed that to undergo natural selection a living entity must have the capacity to replicate itself, the capacity to avoid damage/decay, and the capacity to acquire and process resources in support of the first two capacities. Life on Earth may have started with an RNA world and later evolved to its current form, where some of the RNA tasks were transferred to DNA and proteins. Extraterrestrial life may still be stuck using RNA, or evolve into other configurations. It is unclear if our biochemistry is the most efficient one that could be generated, or which elements would follow a similar pattern. However, it is likely that, even if cells had a different composition to those from Earth, they would still have a cell membrane. Life on Earth jumped from prokaryotes to eukaryotes and from unicellular organisms to multicellular organisms through evolution. So far no alternative process to achieve such a result has been conceived, even if hypothetical. Evolution requires life to be divided into individual organisms, and no alternative organisation has been satisfactorily proposed either. At the basic level, membranes define the limit of a cell, between it and its environment, while remaining partially open to exchange energy and resources with it. The evolution from simple cells to eukaryotes, and from them to multicellular lifeforms, is not guaranteed. The Cambrian explosion took place thousands of millions of years after the origin of life, and its causes are not fully known yet. On the other hand, the jump to multicellularity took place several times, which suggests that it could be a case of convergent evolution, and so likely to take place on other planets as well. Palaeontologist Simon Conway Morris considers that convergent evolution would lead to kingdoms similar to our plants and animals, and that many features are likely to develop in alien animals as well, such as bilateral symmetry, limbs, digestive systems and heads with sensory organs. Scientists from the University of Oxford analysed it from the perspective of evolutionary theory and wrote in a study in the International Journal of Astrobiology that aliens may be similar to humans. The planetary context would also have an influence: a planet with higher gravity would have smaller animals, and other types of stars can lead to non-green photosynthesizers. The amount of energy available would also affect biodiversity, as an ecosystem sustained by black smokers or hydrothermal vents would have less energy available than those sustained by a star's light and heat, and so its lifeforms would not grow beyond a certain complexity. There is also research in assessing the capacity of life for developing intelligence. It has been suggested that this capacity arises with the number of potential niches a planet contains, and that the complexity of life itself is reflected in the information density of planetary environments, which in turn can be computed from its niches. It is common knowledge that the conditions on other planets in the solar system, in addition to the many galaxies outside of the Milky Way galaxy, are very harsh and seem to be too extreme to harbor any life. The environmental conditions on these planets can have intense UV radiation paired with extreme temperatures, lack of water, and much more that can lead to conditions that don't seem to favor the creation or maintenance of extraterrestrial life. However, there has been much historical evidence that some of the earliest and most basic forms of life on Earth originated in some extreme environments that seem unlikely to have harbored life at least at one point in Earth's history. Fossil evidence as well as many historical theories backed up by years of research and studies have marked environments like hydrothermal vents or acidic hot springs as some of the first places that life could have originated on Earth. These environments can be considered extreme when compared to the typical ecosystems that the majority of life on Earth now inhabit, as hydrothermal vents are scorching hot due to the magma escaping from the Earth's mantle and meeting the much colder oceanic water. Even in today's world, there can be a diverse population of bacteria found inhabiting the area surrounding these hydrothermal vents which can suggest that some form of life can be supported even in the harshest of environments like the other planets in the solar system. The aspects of these harsh environments that make them ideal for the origin of life on Earth, as well as the possibility of creation of life on other planets, is the chemical reactions forming spontaneously. For example, the hydrothermal vents found on the ocean floor are known to support many chemosynthetic processes which allow organisms to utilize energy through reduced chemical compounds that fix carbon. In return, these reactions will allow for organisms to live in relatively low oxygenated environments while maintaining enough energy to support themselves. The early Earth environment was reducing and therefore, these carbon fixing compounds were necessary for the survival and possible origin of life on Earth. With the little amount of information that scientists have found regarding the atmosphere on other planets in the Milky Way galaxy and beyond, the atmospheres are most likely reducing or with very low oxygen levels, especially when compared with Earth's atmosphere. If there were the necessary elements and ions on these planets, the same carbon fixing, reduced chemical compounds occurring around hydrothermal vents could also occur on these planets' surfaces and possibly result in the origin of extraterrestrial life. Planetary habitability in the Solar System The Solar System has a wide variety of planets, dwarf planets, and moons, and each one is studied for its potential to host life. Each one has its own specific conditions that may benefit or harm life. So far, the only lifeforms found are those from Earth. No extraterrestrial intelligence other than humans exists or has ever existed within the Solar System. Astrobiologist Mary Voytek points out that it would be unlikely to find large ecosystems, as they would have already been detected by now. The inner Solar System is likely devoid of life. However, Venus is still of interest to astrobiologists, as it is a terrestrial planet that was likely similar to Earth in its early stages and developed in a different way. There is a greenhouse effect, the surface is the hottest in the Solar System, sulfuric acid clouds, all surface liquid water is lost, and it has a thick carbon-dioxide atmosphere with huge pressure. Comparing both helps to understand the precise differences that lead to beneficial or harmful conditions for life. And despite the conditions against life on Venus, there are suspicions that microbial life-forms may still survive in high-altitude clouds. Mars is a cold and almost airless desert, inhospitable to life. However, recent studies revealed that water on Mars used to be quite abundant, forming rivers, lakes, and perhaps even oceans. Mars may have been habitable back then, and life on Mars may have been possible. But when the planetary core ceased to generate a magnetic field, solar winds removed the atmosphere and the planet became vulnerable to solar radiation. Ancient life-forms may still have left fossilised remains, and microbes may still survive deep underground. As mentioned, the gas giants and ice giants are unlikely to contain life. The most distant solar system bodies, found in the Kuiper Belt and outwards, are locked in permanent deep-freeze, but cannot be ruled out completely. Although the giant planets themselves are highly unlikely to have life, there is much hope to find it on moons orbiting these planets. Europa, from the Jovian system, has a subsurface ocean below a thick layer of ice. Ganymede and Callisto also have subsurface oceans, but life is less likely in them because water is sandwiched between layers of solid ice. Europa would have contact between the ocean and the rocky surface, which helps the chemical reactions. It may be difficult to dig so deep in order to study those oceans, though. Enceladus, a tiny moon of Saturn with another subsurface ocean, may not need to be dug, as it releases water to space in eruption columns. The space probe Cassini flew inside one of these, but could not make a full study because NASA did not expect this phenomenon and did not equip the probe to study ocean water. Still, Cassini detected complex organic molecules, salts, evidence of hydrothermal activity, hydrogen, and methane. Titan is the only celestial body in the Solar System besides Earth that has liquid bodies on the surface. It has rivers, lakes, and rain of hydrocarbons, methane, and ethane, and even a cycle similar to Earth's water cycle. This special context encourages speculations about lifeforms with different biochemistry, but the cold temperatures would make such chemistry take place at a very slow pace. Water is rock-solid on the surface, but Titan does have a subsurface water ocean like several other moons. However, it is of such a great depth that it would be very difficult to access it for study. Scientific search The science that searches and studies life in the universe, both on Earth and elsewhere, is called astrobiology. With the study of Earth's life, the only known form of life, astrobiology seeks to study how life starts and evolves and the requirements for its continuous existence. This helps to determine what to look for when searching for life in other celestial bodies. This is a complex area of study, and uses the combined perspectives of several scientific disciplines, such as astronomy, biology, chemistry, geology, oceanography, and atmospheric sciences. The scientific search for extraterrestrial life is being carried out both directly and indirectly. As of September 2017[update], 3,667 exoplanets in 2,747 systems have been identified, and other planets and moons in the Solar System hold the potential for hosting primitive life such as microorganisms. As of 8 February 2021, an updated status of studies considering the possible detection of lifeforms on Venus (via phosphine) and Mars (via methane) was reported. Scientists search for biosignatures within the Solar System by studying planetary surfaces and examining meteorites. Some claim to have identified evidence that microbial life has existed on Mars. In 1996, a controversial report stated that structures resembling nanobacteria were discovered in a meteorite, ALH84001, formed of rock ejected from Mars. Although all the unusual properties of the meteorite were eventually explained as the result of inorganic processes, the controversy over its discovery laid the groundwork for the development of astrobiology. An experiment on the two Viking Mars landers reported gas emissions from heated Martian soil samples that some scientists argue are consistent with the presence of living microorganisms. Lack of corroborating evidence from other experiments on the same samples suggests that a non-biological reaction is a more likely hypothesis. In February 2005 NASA scientists reported they may have found some evidence of extraterrestrial life on Mars. The two scientists, Carol Stoker and Larry Lemke of NASA's Ames Research Center, based their claim on methane signatures found in Mars's atmosphere resembling the methane production of some forms of primitive life on Earth, as well as on their own study of primitive life near the Rio Tinto river in Spain. NASA officials soon distanced NASA from the scientists' claims, and Stoker herself backed off from her initial assertions. In November 2011, NASA launched the Mars Science Laboratory that landed the Curiosity rover on Mars. It is designed to assess the past and present habitability on Mars using a variety of scientific instruments. The rover landed on Mars at Gale Crater in August 2012. A group of scientists at Cornell University started a catalog of microorganisms, with the way each one reacts to sunlight. The goal is to help with the search for similar organisms in exoplanets, as the starlight reflected by planets rich in such organisms would have a specific spectrum, unlike that of starlight reflected from lifeless planets. If Earth was studied from afar with this system, it would reveal a shade of green, as a result of the abundance of plants with photosynthesis. In August 2011, NASA studied meteorites found on Antarctica, finding adenine, guanine, hypoxanthine, and xanthine. Adenine and guanine are components of DNA, and the others are used in other biological processes. The studies ruled out pollution of the meteorites on Earth, as those components would not be freely available the way they were found in the samples. This discovery suggests that several organic molecules that serve as building blocks of life may be generated within asteroids and comets. In October 2011, scientists reported that cosmic dust contains complex organic compounds ("amorphous organic solids with a mixed aromatic-aliphatic structure") that could be created naturally, and rapidly, by stars. It is still unclear if those compounds played a role in the creation of life on Earth, but Sun Kwok, of the University of Hong Kong, thinks so. "If this is the case, life on Earth may have had an easier time getting started as these organics can serve as basic ingredients for life." In August 2012, and in a world first, astronomers at Copenhagen University reported the detection of a specific sugar molecule, glycolaldehyde, in a distant star system. The molecule was found around the protostellar binary IRAS 16293-2422, which is located 400 light years from Earth. Glycolaldehyde is needed to form ribonucleic acid, or RNA, which is similar in function to DNA. This finding suggests that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation. In December 2023, astronomers reported the first time discovery, in the plumes of Enceladus, moon of the planet Saturn, of hydrogen cyanide, a possible chemical essential for life as we know it, as well as other organic molecules, some of which are yet to be better identified and understood. According to the researchers, "these [newly discovered] compounds could potentially support extant microbial communities or drive complex organic synthesis leading to the origin of life." Although most searches are focused on the biology of extraterrestrial life, an extraterrestrial intelligence capable enough to develop a civilization may be detectable by other means as well. Technology may generate technosignatures, effects on the native planet that may not be caused by natural causes. There are three main types of techno-signatures considered: interstellar communications, effects on the atmosphere, and planetary-sized structures such as Dyson spheres. Organizations such as the SETI Institute search the cosmos for potential forms of communication. They started with radio waves, and now search for laser pulses as well. The challenge for this search is that there are natural sources of such signals as well, such as gamma-ray bursts and supernovae, and the difference between a natural signal and an artificial one would be in its specific patterns. Astronomers intend to use artificial intelligence for this, as it can manage large amounts of data and is devoid of biases and preconceptions. Besides, even if there is an advanced extraterrestrial civilization, there is no guarantee that it is transmitting radio communications in the direction of Earth. The length of time required for a signal to travel across space means that a potential answer may arrive decades or centuries after the initial message. The atmosphere of Earth is rich in nitrogen dioxide as a result of air pollution, which can be detectable. The natural abundance of carbon, which is also relatively reactive, makes it likely to be a basic component of the development of a potential extraterrestrial technological civilization, as it is on Earth. Fossil fuels may likely be generated and used on such worlds as well. The abundance of chlorofluorocarbons in the atmosphere can also be a clear technosignature, considering their role in ozone depletion. Light pollution may be another technosignature, as multiple lights on the night side of a rocky planet can be a sign of advanced technological development. However, modern telescopes are not strong enough to study exoplanets with the required level of detail to perceive it. The Kardashev scale proposes that a civilization may eventually start consuming energy directly from its local star. This would require giant structures built next to it, called Dyson spheres. Those speculative structures would cause an excess infrared radiation, that telescopes may notice. The infrared radiation is typical of young stars, surrounded by dusty protoplanetary disks that will eventually form planets. An older star such as the Sun would have no natural reason to have excess infrared radiation. The presence of heavy elements in a star's light-spectrum is another potential biosignature; such elements would (in theory) be found if the star were being used as an incinerator/repository for nuclear waste products. Some astronomers search for extrasolar planets that may be conducive to life, narrowing the search to terrestrial planets within the habitable zones of their stars. Since 1992, over four thousand exoplanets have been discovered (6,128 planets in 4,584 planetary systems including 1,017 multiple planetary systems as of 30 October 2025). The extrasolar planets so far discovered range in size from that of terrestrial planets similar to Earth's size to that of gas giants larger than Jupiter. The number of observed exoplanets is expected to increase greatly in the coming years.[better source needed] The Kepler space telescope has also detected a few thousand candidate planets, of which about 11% may be false positives. There is at least one planet on average per star. About 1 in 5 Sun-like stars[a] have an "Earth-sized"[b] planet in the habitable zone,[c] with the nearest expected to be within 12 light-years distance from Earth. Assuming 200 billion stars in the Milky Way,[d] that would be 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if red dwarfs are included. The rogue planets in the Milky Way possibly number in the trillions. The nearest known exoplanet is Proxima Centauri b, located 4.2 light-years (1.3 pc) from Earth in the southern constellation of Centaurus. As of March 2014[update], the least massive exoplanet known is PSR B1257+12 A, which is about twice the mass of the Moon. The most massive planet listed on the NASA Exoplanet Archive is DENIS-P J082303.1−491201 b, about 29 times the mass of Jupiter, although according to most definitions of a planet, it is too massive to be a planet and may be a brown dwarf instead. Almost all of the planets detected so far are within the Milky Way, but there have also been a few possible detections of extragalactic planets. The study of planetary habitability also considers a wide range of other factors in determining the suitability of a planet for hosting life. One sign that a planet probably already contains life is the presence of an atmosphere with significant amounts of oxygen, since that gas is highly reactive and generally would not last long without constant replenishment. This replenishment occurs on Earth through photosynthetic organisms. One way to analyse the atmosphere of an exoplanet is through spectrography when it transits its star, though this might only be feasible with dim stars like white dwarfs. History and cultural impact The modern concept of extraterrestrial life is based on assumptions that were not commonplace during the early days of astronomy. The first explanations for the celestial objects seen in the night sky were based on mythology. Scholars from Ancient Greece were the first to consider that the universe is inherently understandable and rejected explanations based on supernatural incomprehensible forces, such as the myth of the Sun being pulled across the sky in the chariot of Apollo. They had not developed the scientific method yet and based their ideas on pure thought and speculation, but they developed precursor ideas to it, such as that explanations had to be discarded if they contradict observable facts. The discussions of those Greek scholars established many of the pillars that would eventually lead to the idea of extraterrestrial life, such as Earth being round and not flat. The cosmos was first structured in a geocentric model that considered that the sun and all other celestial bodies revolve around Earth. However, they did not consider them as worlds. In Greek understanding, the world was composed by both Earth and the celestial objects with noticeable movements. Anaximander thought that the cosmos was made from apeiron, a substance that created the world, and that the world would eventually return to the cosmos. Eventually two groups emerged, the atomists that thought that matter at both Earth and the cosmos was equally made of small atoms of the classical elements (earth, water, fire and air), and the Aristotelians who thought that those elements were exclusive of Earth and that the cosmos was made of a fifth one, the aether. Atomist Epicurus thought that the processes that created the world, its animals and plants should have created other worlds elsewhere, along with their own animals and plants. Aristotle thought instead that all the earth element naturally fell towards the center of the universe, and that would make it impossible for other planets to exist elsewhere. Under that reasoning, Earth was not only in the center, it was also the only planet in the universe. Cosmic pluralism, the plurality of worlds, or simply pluralism, describes the philosophical belief in numerous "worlds" in addition to Earth, which might harbor extraterrestrial life. The earliest recorded assertion of extraterrestrial human life is found in ancient scriptures of Jainism. There are multiple "worlds" mentioned in Jain scriptures that support human life. These include, among others, Bharat Kshetra, Mahavideh Kshetra, Airavat Kshetra, and Hari kshetra. Medieval Muslim writers like Fakhr al-Din al-Razi and Muhammad al-Baqir supported cosmic pluralism on the basis of the Qur'an. Chaucer's poem The House of Fame engaged in medieval thought experiments that postulated the plurality of worlds. However, those ideas about other worlds were different from the current knowledge about the structure of the universe, and did not postulate the existence of planetary systems other than the Solar System. When those authors talk about other worlds, they talk about places located at the center of their own systems, and with their own stellar vaults and cosmos surrounding them. The Greek ideas and the disputes between atomists and Aristotelians outlived the fall of the Greek empire. The Great Library of Alexandria compiled information about it, part of which was translated by Islamic scholars and thus survived the end of the Library. Baghdad combined the knowledge of the Greeks, the Indians, the Chinese and its own scholars, and the knowledge expanded through the Byzantine Empire. From there it eventually returned to Europe by the time of the Middle Ages. However, as the Greek atomist doctrine held that the world was created by random movements of atoms, with no need for a creator deity, it became associated with atheism, and the dispute intertwined with religious ones. Still, the Church did not react to those topics in a homogeneous way, and there were stricter and more permissive views within the church itself. The first known mention of the term 'panspermia' was in the writings of the 5th-century BC Greek philosopher Anaxagoras. He proposed the idea that life exists everywhere. By the time of the late Middle Ages there were many known inaccuracies in the geocentric model, but it was kept in use because naked eye observations provided limited data. Nicolaus Copernicus started the Copernican Revolution by proposing that the planets revolve around the sun rather than Earth. His proposal had little acceptance at first because, as he kept the assumption that orbits were perfect circles, his model led to as many inaccuracies as the geocentric one. Tycho Brahe improved the available data with naked-eye observatories, which worked with highly complex sextants and quadrants. Tycho could not make sense of his observations, but Johannes Kepler did: orbits were not perfect circles, but ellipses. This knowledge benefited the Copernican model, which worked now almost perfectly. The invention of the telescope a short time later, perfected by Galileo Galilei, clarified the final doubts, and the paradigm shift was completed. Under this new understanding, the notion of extraterrestrial life became feasible: if Earth is but just a planet orbiting around a star, there may be planets similar to Earth elsewhere. The astronomical study of distant bodies also proved that physical laws are the same elsewhere in the universe as on Earth, with nothing making the planet truly special. The new ideas were met with resistance from the Catholic church. Galileo was tried for the heliocentric model, which was considered heretical, and forced to recant it. The best-known early-modern proponent of ideas of extraterrestrial life was the Italian philosopher Giordano Bruno, who argued in the 16th century for an infinite universe in which every star is surrounded by its own planetary system. Bruno wrote that other worlds "have no less virtue nor a nature different to that of our earth" and, like Earth, "contain animals and inhabitants". Bruno's belief in the plurality of worlds was one of the charges leveled against him by the Venetian Holy Inquisition, which tried and executed him. The heliocentric model was further strengthened by the postulation of the theory of gravity by Sir Isaac Newton. This theory provided the mathematics that explains the motions of all things in the universe, including planetary orbits. By this point, the geocentric model was definitely discarded. By this time, the use of the scientific method had become a standard, and new discoveries were expected to provide evidence and rigorous mathematical explanations. Science also took a deeper interest in the mechanics of natural phenomena, trying to explain not just the way nature works but also the reasons for working that way. There was very little actual discussion about extraterrestrial life before this point, as the Aristotelian ideas remained influential while geocentrism was still accepted. When it was finally proved wrong, it not only meant that Earth was not the center of the universe, but also that the lights seen in the sky were not just lights, but physical objects. The notion that life may exist in them as well soon became an ongoing topic of discussion, although one with no practical ways to investigate. The possibility of extraterrestrials remained a widespread speculation as scientific discovery accelerated. William Herschel, the discoverer of Uranus, was one of many 18th–19th-century astronomers who believed that the Solar System is populated by alien life. Other scholars of the period who championed "cosmic pluralism" included Immanuel Kant and Benjamin Franklin. At the height of the Enlightenment, even the Sun and Moon were considered candidates for extraterrestrial inhabitants. Speculation about life on Mars increased in the late 19th century, following telescopic observation of apparent Martian canals – which soon, however, turned out to be optical illusions. Despite this, in 1895, American astronomer Percival Lowell published his book Mars, followed by Mars and its Canals in 1906, proposing that the canals were the work of a long-gone civilisation. Spectroscopic analysis of Mars's atmosphere began in earnest in 1894, when U.S. astronomer William Wallace Campbell showed that neither water nor oxygen was present in the Martian atmosphere. By 1909 better telescopes and the best perihelic opposition of Mars since 1877 conclusively put an end to the canal hypothesis. As a consequence of the belief in the spontaneous generation there was little thought about the conditions of each celestial body: it was simply assumed that life would thrive anywhere. This theory was disproved by Louis Pasteur in the 19th century. Popular belief in thriving alien civilisations elsewhere in the solar system still remained strong until Mariner 4 and Mariner 9 provided close images of Mars, which debunked forever the idea of the existence of Martians and decreased the previous expectations of finding alien life in general. The end of the spontaneous generation belief forced investigation into the origin of life. Although abiogenesis is the more accepted theory, a number of authors reclaimed the term "panspermia" and proposed that life was brought to Earth from elsewhere. Some of those authors are Jöns Jacob Berzelius (1834), Kelvin (1871), Hermann von Helmholtz (1879) and, somewhat later, by Svante Arrhenius (1903). The science fiction genre, although not so named during the time, developed during the late 19th century. The expansion of the genre of extraterrestrials in fiction influenced the popular perception over the real-life topic, making people eager to jump to conclusions about the discovery of aliens. Science marched at a slower pace, some discoveries fueled expectations and others dashed excessive hopes. For example, with the advent of telescopes, most structures seen on the Moon or Mars were immediately attributed to Selenites or Martians, and later ones (such as more powerful telescopes) revealed that all such discoveries were natural features. A famous case is the Cydonia region of Mars, first imaged by the Viking 1 orbiter. The low-resolution photos showed a rock formation that resembled a human face, but later spacecraft took photos in higher detail that showed that there was nothing special about the site. The search and study of extraterrestrial life became a science of its own, astrobiology. Also known as exobiology, this discipline is studied by the NASA, the ESA, the INAF, and others. Astrobiology studies life from Earth as well, but with a cosmic perspective. For example, abiogenesis is of interest to astrobiology, not because of the origin of life on Earth, but for the chances of a similar process taking place in other celestial bodies. Many aspects of life, from its definition to its chemistry, are analyzed as either likely to be similar in all forms of life across the cosmos or only native to Earth. Astrobiology, however, remains constrained by the current lack of extraterrestrial life-forms to study, as all life on Earth comes from the same ancestor, and it is hard to infer general characteristics from a group with a single example to analyse. The 20th century came with great technological advances, speculations about future hypothetical technologies, and an increased basic knowledge of science by the general population thanks to science divulgation through the mass media. The public interest in extraterrestrial life and the lack of discoveries by mainstream science led to the emergence of pseudosciences that provided affirmative, if questionable, answers to the existence of aliens. Ufology claims that many unidentified flying objects (UFOs) would be spaceships from alien species, and ancient astronauts hypothesis claim that aliens would have visited Earth in antiquity and prehistoric times but people would have failed to understand it by then. Most UFOs or UFO sightings can be readily explained as sightings of Earth-based aircraft (including top-secret aircraft), known astronomical objects or weather phenomenons, or as hoaxes. Looking beyond the pseudosciences, Lewis White Beck strove to elevate the level of public discourse on the topic of extraterrestrial life by tracing the evolution of philosophical thought over the centuries from ancient times into the modern era. His review of the contributions made by Lucretius, Plutarch, Aristotle, Copernicus, Immanuel Kant, John Wilkins, Charles Darwin and Karl Marx demonstrated that even in modern times, humanity could be profoundly influenced in its search for extraterrestrial life by subtle and comforting archetypal ideas which are largely derived from firmly held religious, philosophical and existential belief systems. On a positive note, however, Beck further argued that even if the search for extraterrestrial life proves to be unsuccessful, the endeavor itself could have beneficial consequences by assisting humanity in its attempt to actualize superior ways of living here on Earth. By the 21st century, it was accepted that multicellular life in the Solar System can only exist on Earth, but the interest in extraterrestrial life increased regardless. This is a result of the advances in several sciences. The knowledge of planetary habitability allows to consider on scientific terms the likelihood of finding life at each specific celestial body, as it is known which features are beneficial and harmful for life. Astronomy and telescopes also improved to the point exoplanets can be confirmed and even studied, increasing the number of search places. Life may still exist elsewhere in the Solar System in unicellular form, but the advances in spacecraft allow to send robots to study samples in situ, with tools of growing complexity and reliability. Although no extraterrestrial life has been found and life may still be just a rarity from Earth, there are scientific reasons to suspect that it can exist elsewhere, and technological advances that may detect it if it does. Many scientists are optimistic about the chances of finding alien life. In the words of SETI's Frank Drake, "All we know for sure is that the sky is not littered with powerful microwave transmitters". Drake noted that it is entirely possible that advanced technology results in communication being carried out in some way other than conventional radio transmission. At the same time, the data returned by space probes, and giant strides in detection methods, have allowed science to begin delineating habitability criteria on other worlds, and to confirm that at least other planets are plentiful, though aliens remain a question mark. The Wow! signal, detected in 1977 by a SETI project, remains a subject of speculative debate. On the other hand, other scientists are pessimistic. Jacques Monod wrote that "Man knows at last that he is alone in the indifferent immensity of the universe, whence which he has emerged by chance". In 2000, geologist and paleontologist Peter Ward and astrobiologist Donald Brownlee published a book entitled Rare Earth: Why Complex Life is Uncommon in the Universe.[better source needed] In it, they discussed the Rare Earth hypothesis, in which they claim that Earth-like life is rare in the universe, whereas microbial life is common. Ward and Brownlee are open to the idea of evolution on other planets that is not based on essential Earth-like characteristics such as DNA and carbon. As for the possible risks, theoretical physicist Stephen Hawking warned in 2010 that humans should not try to contact alien life forms. He warned that aliens might pillage Earth for resources. "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans", he said. Jared Diamond had earlier expressed similar concerns. On 20 July 2015, Hawking and Russian billionaire Yuri Milner, along with the SETI Institute, announced a well-funded effort, called the Breakthrough Initiatives, to expand efforts to search for extraterrestrial life. The group contracted the services of the 100-meter Robert C. Byrd Green Bank Telescope in West Virginia in the United States and the 64-meter Parkes Telescope in New South Wales, Australia. On 13 February 2015, scientists (including Geoffrey Marcy, Seth Shostak, Frank Drake and David Brin) at a convention of the American Association for the Advancement of Science, discussed Active SETI and whether transmitting a message to possible intelligent extraterrestrials in the Cosmos was a good idea; one result was a statement, signed by many, that a "worldwide scientific, political and humanitarian discussion must occur before any message is sent". Government responses The 1967 Outer Space Treaty and the 1979 Moon Agreement define rules of planetary protection against potentially hazardous extraterrestrial life. COSPAR also provides guidelines for planetary protection. A committee of the United Nations Office for Outer Space Affairs had in 1977 discussed for a year strategies for interacting with extraterrestrial life or intelligence. The discussion ended without any conclusions. As of 2010, the UN lacks response mechanisms for the case of an extraterrestrial contact. One of the NASA divisions is the Office of Safety and Mission Assurance (OSMA), also known as the Planetary Protection Office. A part of its mission is to "rigorously preclude backward contamination of Earth by extraterrestrial life." In 2016, the Chinese Government released a white paper detailing its space program. According to the document, one of the research objectives of the program is the search for extraterrestrial life. It is also one of the objectives of the Chinese Five-hundred-meter Aperture Spherical Telescope (FAST) program. In 2020, Dmitry Rogozin, the head of the Russian space agency, said the search for extraterrestrial life is one of the main goals of deep space research. He also acknowledged the possibility of existence of primitive life on other planets of the Solar System. The French space agency has an office for the study of "non-identified aero spatial phenomena". The agency is maintaining a publicly accessible database of such phenomena, with over 1600 detailed entries. According to the head of the office, the vast majority of entries have a mundane explanation; but for 25% of entries, their extraterrestrial origin can neither be confirmed nor denied. In 2020, chairman of the Israel Space Agency Isaac Ben-Israel stated that the probability of detecting life in outer space is "quite large". But he disagrees with his former colleague Haim Eshed who stated that there are contacts between an advanced alien civilisation and some of Earth's governments. In fiction Although the idea of extraterrestrial peoples became feasible once astronomy developed enough to understand the nature of planets, they were not thought of as being any different from humans. Having no scientific explanation for the origin of mankind and its relation to other species, there was no reason to expect them to be any other way. This was changed by the 1859 book On the Origin of Species by Charles Darwin, which proposed the theory of evolution. Now with the notion that evolution on other planets may take other directions, science fiction authors created bizarre aliens, clearly distinct from humans. A usual way to do that was to add body features from other animals, such as insects or octopuses. Costuming and special effects feasibility alongside budget considerations forced films and TV series to tone down the fantasy, but these limitations lessened since the 1990s with the advent of computer-generated imagery (CGI), and later on as CGI became more effective and less expensive. Real-life events sometimes captivate people's imagination and this influences the works of fiction. For example, during the Barney and Betty Hill incident, the first recorded claim of an alien abduction, the couple reported that they were abducted and experimented on by aliens with oversized heads, big eyes, pale grey skin, and small noses, a description that eventually became the grey alien archetype once used in works of fiction. See also Notes References Further reading External links
========================================

[SOURCE: https://en.wikipedia.org/wiki/Cloob] \| [TOKENS: 439]
Contents Cloob Cloob.com was a Persian-language social networking website, mainly popular in Iran. After the locally (and internationally) popular social networking website Orkut was blocked by the Iranian government, a series of local sites and networks, including Cloob, emerged to fill the gap. Its main page contains the title Iranian Virtual Society and states that all content is controlled in accordance with Iranian law, a policy intended to lower the risk of government censorship. The website claims to have around 1 million members and over 100 million page views per month. Users have access to features like: internal email (for individual friends, groups of friends and community members), communities and community discussions (clubs), personal and community photo albums, article archive for communities, live messaging and chat rooms for communities, weblog, job and resume database, virtual money (called "coroob"), income/expense book keeping for individual members, online shops for offering goods and services, classifieds, questions and answers, link and content sharing, news, member updates and extensive permission setting capabilities. Some of the services consume virtual money. For example, advanced search in community discussions, advanced member search, receipt for email messages, list of profile visitors and a few other services will use different amounts of members' available virtual money. It is possible to buy virtual money or transfer it to other users. Cloob was censored on March 7, 2008 (the period of Parliament elections) by the government of Iran. However, after what the Cloob management called "removal of illegal and controversial content", access was restored to Iranian internet users on April 29, 2008. On December 25, 2009 it was once again censored and remained so for some time, but as of 2011, Cloob appears to be in working order once again. In 2021, Cloob shut down citing they were worn out having to fight censorship and the government letting foreign companies such as instagram take over. References External links This website-related article is a stub. You can help Wikipedia by adding missing information. This Iran-related article is a stub. You can help Wikipedia by adding missing information.
========================================

[SOURCE: https://www.theverge.com/podcast/879965/foldable-phone-laptop-keyboard-sports-streaming-vergecast] \| [TOKENS: 1873]
PodcastsClosePodcastsPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PodcastsStreamingCloseStreamingPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All StreamingTechCloseTechPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All TechYour next laptop could be a foldable phoneOn The Vergecast: purse computers, Olympic drones, and AI flip phones.On The Vergecast: purse computers, Olympic drones, and AI flip phones.by David PierceCloseDavid PierceEditor-at-LargePosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by David PierceFeb 17, 2026, 3:46 PM UTCLinkShareGiftIf you buy something from a Verge link, Vox Media may earn a commission. See our ethics statement.David PierceCloseDavid PiercePosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by David Pierce is editor-at-large and Vergecast co-host with over a decade of experience covering consumer tech. Previously, at Protocol, The Wall Street Journal, and Wired.For almost as long as phones have been around, people have wanted those phones to also be laptops. It seems so simple: Your phone has plenty of computing power, access to all your apps and data, an always-on connection. The only problem? Your phone’s screen is too small for many tasks, and so is its keyboard. Or at least, they were, until foldable phones made it possible to carry a truly gigantic screen in your pocket. Now all bets are off.Verge subscribers, don’t forget you get exclusive access to ad-free Vergecast wherever you get your podcasts. Head here. Not a subscriber? You can sign up here.On this episode of The Vergecast, The Verge’s Allison Johnson explains how she turned a Samsung Galaxy Z Fold 7 into her on-the-go laptop. It took a little work, and at least one new accessory, but she’s actually starting to leave her laptop home more often. There’s even a chance that Google’s Android team and app developers might start to make the system work even better.After that, it’s time for an update on the world of sports streaming. Sportico’s Jacob Feldman joins the show to talk about the whirring drones all over the Winter Olympics coverage, the boring (in a good way) Super Bowl we just had, YouTube’s increasing leverage over both the TV world and the sports world, and whether the Netflix / Paramount / Warner Bros. deal will change the streaming landscape. The good news is, sports streaming is better than ever. The bad news is, chaos reigns.After that, David takes a question from the Vergecast Hotline (call 866-VERGE11 or email vergecast@theverge.com) about flip phones, AI, and whether one device can feel and work like two devices. The answer is yes, in theory, we think. But the software doesn’t work. Subscribe: Spotify \| Apple Podcasts \| Overcast \| Pocket Casts \| MoreIf you want to know more about everything we discuss in this episode, here are some links to get you started:Who needs a laptop when you have a folding phone?Samsung Galaxy Z Fold 7 review: stunning, bendy, and spendyMotorola Razr Ultra (2025) review: looking sharpLogitech’s Keys-To-Go 2YouTube TV reveals pricing for its sports, news, and entertainment packagesFrom Sportico: 2026 Sports Tech: Amazon vs. Youtube vs. ESPN vs. Netflix vs. TiktokFrom The Athletic: At Winter Olympics, drone cameras are pushing limits for viewers — and athletesFollow topics and authors from this story to see more like this in your personalized homepage feed and to receive email updates.David PierceCloseDavid PierceEditor-at-LargePosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by David PiercePodcastsClosePodcastsPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PodcastsSamsungCloseSamsungPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All SamsungStreamingCloseStreamingPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All StreamingTechCloseTechPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All TechVergecastCloseVergecastPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All VergecastMost PopularMost PopularXbox chief Phil Spencer is leaving MicrosoftRead Microsoft gaming CEO Asha Sharma’s first memo on the future of XboxThe RAM shortage is coming for everything you care aboutAmazon blames human employees for an AI coding agent’s mistakeWill Stancil, man of the people or just an annoying guy?The Verge DailyA free daily digest of the news that matters most.Email (required)Sign UpBy submitting your email, you agree to our Terms and Privacy Notice. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.Advertiser Content FromThis is the title for the native ad Posts from this topic will be added to your daily email digest and your homepage feed. See All Podcasts Posts from this topic will be added to your daily email digest and your homepage feed. See All Streaming Posts from this topic will be added to your daily email digest and your homepage feed. See All Tech Your next laptop could be a foldable phone On The Vergecast: purse computers, Olympic drones, and AI flip phones. On The Vergecast: purse computers, Olympic drones, and AI flip phones. Posts from this author will be added to your daily email digest and your homepage feed. See All by David Pierce If you buy something from a Verge link, Vox Media may earn a commission. See our ethics statement. Posts from this author will be added to your daily email digest and your homepage feed. See All by David Pierce For almost as long as phones have been around, people have wanted those phones to also be laptops. It seems so simple: Your phone has plenty of computing power, access to all your apps and data, an always-on connection. The only problem? Your phone’s screen is too small for many tasks, and so is its keyboard. Or at least, they were, until foldable phones made it possible to carry a truly gigantic screen in your pocket. Now all bets are off. Verge subscribers, don’t forget you get exclusive access to ad-free Vergecast wherever you get your podcasts. Head here. Not a subscriber? You can sign up here. On this episode of The Vergecast, The Verge’s Allison Johnson explains how she turned a Samsung Galaxy Z Fold 7 into her on-the-go laptop. It took a little work, and at least one new accessory, but she’s actually starting to leave her laptop home more often. There’s even a chance that Google’s Android team and app developers might start to make the system work even better. After that, it’s time for an update on the world of sports streaming. Sportico’s Jacob Feldman joins the show to talk about the whirring drones all over the Winter Olympics coverage, the boring (in a good way) Super Bowl we just had, YouTube’s increasing leverage over both the TV world and the sports world, and whether the Netflix / Paramount / Warner Bros. deal will change the streaming landscape. The good news is, sports streaming is better than ever. The bad news is, chaos reigns. After that, David takes a question from the Vergecast Hotline (call 866-VERGE11 or email vergecast@theverge.com) about flip phones, AI, and whether one device can feel and work like two devices. The answer is yes, in theory, we think. But the software doesn’t work. Subscribe: Spotify \| Apple Podcasts \| Overcast \| Pocket Casts \| More If you want to know more about everything we discuss in this episode, here are some links to get you started: Posts from this author will be added to your daily email digest and your homepage feed. See All by David Pierce Posts from this topic will be added to your daily email digest and your homepage feed. See All Podcasts Posts from this topic will be added to your daily email digest and your homepage feed. See All Samsung Posts from this topic will be added to your daily email digest and your homepage feed. See All Streaming Posts from this topic will be added to your daily email digest and your homepage feed. See All Tech Posts from this topic will be added to your daily email digest and your homepage feed. See All Vergecast Most Popular The Verge Daily A free daily digest of the news that matters most. This is the title for the native ad More in Podcasts This is the title for the native ad Top Stories © 2026 Vox Media, LLC. All Rights Reserved
========================================

[SOURCE: https://www.wired.com/video/watch/elon-musk-appears-to-be-violating-us-sanctions-by-providing-x-premium-accounts-to-iran] \| [TOKENS: 378]
Elon Musk Appears To Be Violating US Sanctions By Providing X Premium Accounts To Iran Released on 02/12/2026 Elon Musk's X potentially violated US sanctions by appearing to allow Iranian government officials to subscribe to its X Premium service. That's according to a new report from the Tech Transparency Project shared exclusively with WIRED. While the Iranian regime was brutally cracking down on protesters and imposing an internet blackout, drawing condemnation from Musk and the Trump administration, more than two dozen X accounts allegedly run by government officials, state agencies, and state-run news outlets displayed a blue checkmark as they shared state-sponsored propaganda. X did not respond to a request for comment, but within hours of WIRED highlighting a number of the accounts belonging to the Iranian officials, their blue checkmarks were removed. However, the rest of the accounts identified by the Tech Transparency Project but not shared with X still have their blue checkmark. Massachusetts Senator Elizabeth Warren, who wrote to the Treasuring following the publication of another report by the Tech Transparency Project that found X was providing blue checkmarks to US-sanctioned terrorists, tells WIRED in a statement, By failing to take basic steps to enforce our sanctions, the Trump administration continues to undermine our national security and the integrity of our financial system. Read the full story at WIRED.com. Trending video Collectibles Expert Answers Collectibles Questions Olympian Answers Figure Skating Questions Paralympian Answers Paralympics Questions I Escaped Chinese Mafia Crypto Slavery Professor Answers Olympic History Questions © 2026 Condé Nast. All rights reserved. WIRED may earn a portion of sales from products that are purchased through our site as part of our Affiliate Partnerships with retailers. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Condé Nast. Ad Choices
========================================

[SOURCE: https://www.ynet.co.il/economy/article/hy1m2kxdwg] \| [TOKENS: 432]
האישה שהוציאה מהארון את הפוסט טראומה: "מאות אלפי ישראלים סובלים" יהודית יובל רקנאטי היא בת לאחת ממשפחות העסקים העשירות והמפורסמות בישראל שהקימה בין השאר את בנק דיסקונט. כיום היא מקדישה את עיקר זמנה לעמותת נט"ל, שאותה ייסדה לטיפול בנפגעי פוסט טראומה. עכשיו היא מספרת על העלייה העצומה במספר הנפגעים מאז 7 באוקטובר ועל החשיבות הכלכלית והחברתית העצומה של ההכרה ב"פציעה השקטה": ‏‏"המטופלים לא מחפשים ליפול על המדינה, רק לחזור למעגל העבודה"‏
========================================

[SOURCE: https://en.wikipedia.org/wiki/Slate_Star_Codex] \| [TOKENS: 1565]
Contents Slate Star Codex Astral Codex Ten (ACX), formerly Slate Star Codex (SSC), is a blog focused on science, medicine (especially psychiatry), philosophy, politics, and futurism. The blog is written by Scott Alexander Siskind, a San Francisco Bay Area psychiatrist, under the pen name Scott Alexander. Slate Star Codex was launched in 2013 and was temporarily discontinued on June 23, 2020. In July 2020 the blog was partially back online, with the content restored but commenting disabled. The successor Substack blog, Astral Codex Ten, was launched on January 21, 2021. Content and author The site was a primary venue of the rationalist community and also attracted wider audiences. The New Statesman characterizes it as "a nexus for the rationalist community and others who seek to apply reason to debates about situations, ideas, and moral quandaries." The New Yorker describes Alexander's fiction as "delightfully weird" and his arguments "often counterintuitive and brilliant". Economist Tyler Cowen calls Scott Alexander "a thinker who is influential among other writers". The New Yorker states that the volume of content Alexander has written on Slate Star Codex makes the blog difficult to summarize, with an e-book of all posts running over nine thousand pages in PDF form. Many posts are book reviews (typically of books in the fields of social sciences or medicine) or reviews of a topic in the scientific literature. For example, the March 2020 blog post "Face Masks: Much More Than You Wanted To Know" analyzes available medical literature and comes to a conclusion that contrary to early guidance by the CDC, masks are likely an effective protection measure against COVID-19 for the general public under certain conditions. Some posts are prefaced with a note on their "epistemic status", an assessment of Alexander's confidence in the material to follow. Alexander also blogged at the rationalist community blog LessWrong, and wrote a fiction book in blog format named Unsong. Alexander published a revised version of Unsong on May 24, 2024. In 2017, Slate Star Codex ranked fourth on a survey conducted by Rethink Charity of how effective altruists first heard about effective altruism, after "personal contact", "LessWrong", and "other books, articles and blog posts", and just above "80,000 Hours." The blog discusses moral questions and dilemmas relevant to effective altruism, such as moral offsets (the proposition that good acts can cancel out bad acts), ethical treatment of animals, and trade-offs of pursuing systemic change for charities. Alexander regularly writes about advances in artificial intelligence and emphasized the importance of AI safety research. In the long essay "Meditations On Moloch", he analyzes game-theoretic scenarios of cooperation failure like the prisoner's dilemma and the tragedy of the commons that underlie many of humanity's problems and argues that AI risks should be considered in this context. In "The Toxoplasma of Rage", Alexander discusses how controversies spread in media and social networks. According to Alexander, memes that generate a lot of disagreement spread further, in part because they present an opportunity to members of different groups to send a strong signal of commitment to their cause. For example, he argues that PETA, with its controversial campaigns, is better known than other animal rights organizations such as Vegan Outreach because of this dynamic. Another example of this cited by Alexander is the Rolling Stone article "A Rape on Campus". In the short story "Sort By Controversial", Alexander introduces the term "Shiri's scissor" or "scissor statement" to describe a statement that has great destructive power because it generates wildly divergent interpretations that fuel conflict and tear people apart. The term has been used to describe controversial topics widely discussed in social media. The 2013 post "The Anti-Reactionary FAQ" critiques the work and worldview of the neoreactionary movement, arguing against the work of Curtis Yarvin (whose views include a belief in natural racial hierarchies and a desire to restore feudalism). Alexander allowed neo-reactionaries to comment on posts and in "culture war" threads on the forum because he wanted to promote an open marketplace of ideas; Alexander engaged in extended dialogues with these users, including his thirty-thousand-word FAQ. Alexander's essays on neoreaction have been cited by David Auerbach and Dylan Matthews as explanations of the movement. In the 2013 post "Lizardman's Constant is 4%", Alexander coined the term "Lizardman's Constant", referring to the approximate percentage of responses to a poll, survey, or quiz that are not sincere. The post was responding to a Public Policy Polling statement that "four percent of Americans believe lizardmen are running the Earth", which Alexander attributed to people giving a polling company an answer they did not really believe to be true, out of carelessness, politeness, anger, or amusement. Alexander suggested that polls should include a question with an absurd answer as one of the options, so anyone choosing that option could be weeded out as a troll. The New York Times controversy Alexander used his first and middle name alone for safety and privacy reasons, although he had previously published Slate Star Codex content academically under his real name. In June 2020, he deleted all entries on Slate Star Codex, stating that a technology reporter from The New York Times (NYT) intended to publish an article about the blog using his full name. Alexander said that the reporter told him that it was newspaper policy to use real names, and he referred to it as doxing. The New York Times responded: "We do not comment on what we may or may not publish in the future. But when we report on newsworthy or influential figures, our goal is always to give readers all the accurate and relevant information we can." The Verge cited a source saying that at the time when Alexander deleted the blog, "not a word" of a story about SSC had been written. The Poynter Institute's David Cohn interpreted this event as part of an ongoing clash between the tech and media industries, reflecting a shift from primarily economic conflicts to fundamental disagreements over values, ethics, and cultural norms. Prior to the article's publication, several commentators argued that The New York Times should not publish Alexander's name without good reason. Writing in National Review, Tobias Hoonhout said that the newspaper had applied its anonymity policy inconsistently. The New Statesman's Jasper Jackson wrote that it was "difficult to see how Scott Alexander's full name is so integral to the NYT's story that it justifies the damage it might do to him", but cautioned that such criticism was based solely on Alexander's own statements and that "before we make that call, it might be a good idea to have more than his word to go on." As reported by The Daily Beast, the criticism by Alexander and his supporters that the paper was doxing him caused internal debate among The New York Times' staff. Supporters of the site organized a petition against release of the author's name. The petition collected over six thousand signatures in its first few days, including psychologist Steven Pinker, social psychologist Jonathan Haidt, economist Scott Sumner, computer scientist and blogger Scott Aaronson, and philosopher Peter Singer. According to New Statesman columnist Louise Perry, Scott Alexander wrote that he quit his job and took measures that made him comfortable with revealing his real name, which he published on Astral Codex Ten. The New York Times published an article about the blog in February 2021, three weeks after Alexander had publicly revealed his name. References External links
========================================

[SOURCE: https://www.mako.co.il/food-restaurants/restaurant-news/Article-801d7a08c806c91027.htm] \| [TOKENS: 96]
We are sorry... ...but your activity and behavior on this website made us think that you are a bot. Please solve this CAPTCHA in helping us understand your behavior to grant access You reached this page when trying to access https://www.mako.co.il/food-restaurants/restaurant-news/Article-801d7a08c806c91027.htm from 79.181.162.231 on February 21 2026, 10:56:41 UTC
========================================

[SOURCE: https://en.wikipedia.org/wiki/Internet#cite_ref-132] \| [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
========================================

[SOURCE: https://en.wikipedia.org/wiki/BBC_News#cite_note-19] \| [TOKENS: 8810]
Contents BBC News BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online news coverage. The service has over 5,500 journalists working across its output including in 50 foreign news bureaus where more than 250 foreign correspondents are stationed. Deborah Turness has been the CEO of news and current affairs since September 2022. In 2019, it was reported in an Ofcom report that the BBC spent £136m on news during the period April 2018 to March 2019. BBC News' domestic, global and online news divisions are housed within the largest live newsroom in Europe, in Broadcasting House in central London. Parliamentary coverage is produced and broadcast from studios in London. Through BBC English Regions, the BBC also has regional centres across England and national news centres in Northern Ireland, Scotland and Wales. All nations and English regions produce their own local news programmes and other current affairs and sport programmes. The BBC is a quasi-autonomous corporation authorised by royal charter, making it operationally independent of the government. As of 2024, the BBC reaches an average of 450 million people per week, with the BBC World Service accounting for 320 million people. History This is London calling – 2LO calling. Here is the first general news bulletin, copyright by Reuters, Press Association, Exchange Telegraph and Central News. — BBC news programme opening during the 1920s The British Broadcasting Company broadcast its first radio bulletin from radio station 2LO on 14 November 1922. Wishing to avoid competition, newspaper publishers persuaded the government to ban the BBC from broadcasting news before 7 pm, and to force it to use wire service copy instead of reporting on its own. The BBC gradually gained the right to edit the copy and, in 1934, created its own news operation. However, it could not broadcast news before 6 p.m. until World War II. In addition to news, Gaumont British and Movietone cinema newsreels had been broadcast on the TV service since 1936, with the BBC producing its own equivalent Television Newsreel programme from January 1948. A weekly Children's Newsreel was inaugurated on 23 April 1950, to around 350,000 receivers. The network began simulcasting its radio news on television in 1946, with a still picture of Big Ben. Televised bulletins began on 5 July 1954, broadcast from leased studios within Alexandra Palace in London. The public's interest in television and live events was stimulated by Elizabeth II's coronation in 1953. It is estimated that up to 27 million people viewed the programme in the UK, overtaking radio's audience of 12 million for the first time. Those live pictures were fed from 21 cameras in central London to Alexandra Palace for transmission, and then on to other UK transmitters opened in time for the event. That year, there were around two million TV Licences held in the UK, rising to over three million the following year, and four and a half million by 1955. Television news, although physically separate from its radio counterpart, was still firmly under radio news' control in the 1950s. Correspondents provided reports for both outlets, and the first televised bulletin, shown on 5 July 1954 on the then BBC television service and presented by Richard Baker, involved his providing narration off-screen while stills were shown. This was then followed by the customary Television Newsreel with a recorded commentary by John Snagge (and on other occasions by Andrew Timothy). On-screen newsreaders were introduced a year later in 1955 – Kenneth Kendall (the first to appear in vision), Robert Dougall, and Richard Baker—three weeks before ITN's launch on 21 September 1955. Mainstream television production had started to move out of Alexandra Palace in 1950 to larger premises – mainly at Lime Grove Studios in Shepherd's Bush, west London – taking Current Affairs (then known as Talks Department) with it. It was from here that the first Panorama, a new documentary programme, was transmitted on 11 November 1953, with Richard Dimbleby becoming anchor in 1955. In 1958, Hugh Carleton Greene became head of News and Current Affairs. On 1 January 1960, Greene became Director-General. Greene made changes that were aimed at making BBC reporting more similar to its competitor ITN, which had been highly rated by study groups held by Greene. A newsroom was created at Alexandra Palace, television reporters were recruited and given the opportunity to write and voice their own scripts, without having to cover stories for radio too. On 20 June 1960, Nan Winton, the first female BBC network newsreader, appeared in vision. 19 September 1960 saw the start of the radio news and current affairs programme The Ten O'clock News. BBC2 started transmission on 20 April 1964 and began broadcasting a new show, Newsroom. The World at One, a lunchtime news programme, began on 4 October 1965 on the then Home Service, and the year before News Review had started on television. News Review was a summary of the week's news, first broadcast on Sunday, 26 April 1964 on BBC 2 and harking back to the weekly Newsreel Review of the Week, produced from 1951, to open programming on Sunday evenings–the difference being that this incarnation had subtitles for the deaf and hard-of-hearing. As this was the decade before electronic caption generation, each superimposition ("super") had to be produced on paper or card, synchronised manually to studio and news footage, committed to tape during the afternoon, and broadcast early evening. Thus Sundays were no longer a quiet day for news at Alexandra Palace. The programme ran until the 1980s – by then using electronic captions, known as Anchor – to be superseded by Ceefax subtitling (a similar Teletext format), and the signing of such programmes as See Hear (from 1981). On Sunday 17 September 1967, The World This Weekend, a weekly news and current affairs programme, launched on what was then Home Service, but soon-to-be Radio 4. Preparations for colour began in the autumn of 1967 and on Thursday 7 March 1968 Newsroom on BBC2 moved to an early evening slot, becoming the first UK news programme to be transmitted in colour – from Studio A at Alexandra Palace. News Review and Westminster (the latter a weekly review of Parliamentary happenings) were "colourised" shortly after. However, much of the insert material was still in black and white, as initially only a part of the film coverage shot in and around London was on colour reversal film stock, and all regional and many international contributions were still in black and white. Colour facilities at Alexandra Palace were technically very limited for the next eighteen months, as it had only one RCA colour Quadruplex videotape machine and, eventually two Pye plumbicon colour telecines–although the news colour service started with just one. Black and white national bulletins on BBC 1 continued to originate from Studio B on weekdays, along with Town and Around, the London regional "opt out" programme broadcast throughout the 1960s (and the BBC's first regional news programme for the South East), until it started to be replaced by Nationwide on Tuesday to Thursday from Lime Grove Studios early in September 1969. Town and Around was never to make the move to Television Centre – instead it became London This Week which aired on Mondays and Fridays only, from the new TVC studios. The BBC moved production out of Alexandra Palace in 1969. BBC Television News resumed operations the next day with a lunchtime bulletin on BBC1 – in black and white – from Television Centre, where it remained until March 2013. This move to a smaller studio with better technical facilities allowed Newsroom and News Review to replace back projection with colour-separation overlay. During the 1960s, satellite communication had become possible; however, it was some years before digital line-store conversion was able to undertake the process seamlessly. On 14 September 1970, the first Nine O'Clock News was broadcast on television. Robert Dougall presented the first week from studio N1 – described by The Guardian as "a sort of polystyrene padded cell"—the bulletin having been moved from the earlier time of 20.50 as a response to the ratings achieved by ITN's News at Ten, introduced three years earlier on the rival ITV. Richard Baker and Kenneth Kendall presented subsequent weeks, thus echoing those first television bulletins of the mid-1950s. Angela Rippon became the first female news presenter of the Nine O'Clock News in 1975. Her work outside the news was controversial at the time, appearing on The Morecambe and Wise Christmas Show in 1976 singing and dancing. The first edition of John Craven's Newsround, initially intended only as a short series and later renamed just Newsround, came from studio N3 on 4 April 1972. Afternoon television news bulletins during the mid to late 1970s were broadcast from the BBC newsroom itself, rather than one of the three news studios. The newsreader would present to camera while sitting on the edge of a desk; behind him staff would be seen working busily at their desks. This period corresponded with when the Nine O'Clock News got its next makeover, and would use a CSO background of the newsroom from that very same camera each weekday evening. Also in the mid-1970s, the late night news on BBC2 was briefly renamed Newsnight, but this was not to last, or be the same programme as we know today – that would be launched in 1980 – and it soon reverted to being just a news summary with the early evening BBC2 news expanded to become Newsday. News on radio was to change in the 1970s, and on Radio 4 in particular, brought about by the arrival of new editor Peter Woon from television news and the implementation of the Broadcasting in the Seventies report. These included the introduction of correspondents into news bulletins where previously only a newsreader would present, as well as the inclusion of content gathered in the preparation process. New programmes were also added to the daily schedule, PM and The World Tonight as part of the plan for the station to become a "wholly speech network". Newsbeat launched as the news service on Radio 1 on 10 September 1973. On 23 September 1974, a teletext system which was launched to bring news content on television screens using text only was launched. Engineers originally began developing such a system to bring news to deaf viewers, but the system was expanded. The Ceefax service became much more diverse before it ceased on 23 October 2012: it not only had subtitling for all channels, it also gave information such as weather, flight times and film reviews. By the end of the decade, the practice of shooting on film for inserts in news broadcasts was declining, with the introduction of ENG technology into the UK. The equipment would gradually become less cumbersome – the BBC's first attempts had been using a Philips colour camera with backpack base station and separate portable Sony U-matic recorder in the latter half of the decade. In 1980, the Iranian Embassy Siege had been shot electronically by the BBC Television News Outside broadcasting team, and the work of reporter Kate Adie, broadcasting live from Prince's Gate, was nominated for BAFTA actuality coverage, but this time beaten by ITN for the 1980 award. Newsnight, the news and current affairs programme, was due to go on air on 23 January 1980, although trade union disagreements meant that its launch from Lime Grove was postponed by a week. On 27 August 1981 Moira Stuart became the first African Caribbean female newsreader to appear on British television. By 1982, ENG technology had become sufficiently reliable for Bernard Hesketh to use an Ikegami camera to cover the Falklands War, coverage for which he won the "Royal Television Society Cameraman of the Year" award and a BAFTA nomination – the first time that BBC News had relied upon an electronic camera, rather than film, in a conflict zone. BBC News won the BAFTA for its actuality coverage, however the event has become remembered in television terms for Brian Hanrahan's reporting where he coined the phrase "I'm not allowed to say how many planes joined the raid, but I counted them all out and I counted them all back" to circumvent restrictions, and which has become cited as an example of good reporting under pressure. The first BBC breakfast television programme, Breakfast Time also launched during the 1980s, on 17 January 1983 from Lime Grove Studio E and two weeks before its ITV rival TV-am. Frank Bough, Selina Scott, and Nick Ross helped to wake viewers with a relaxed style of presenting. The Six O'Clock News first aired on 3 September 1984, eventually becoming the most watched news programme in the UK (however, since 2006 it has been overtaken by the BBC News at Ten). In October 1984, images of millions of people starving to death in the Ethiopian famine were shown in Michael Buerk's Six O'Clock News reports. The BBC News crew were the first to document the famine, with Buerk's report on 23 October describing it as "a biblical famine in the 20th century" and "the closest thing to hell on Earth". The BBC News report shocked Britain, motivating its citizens to inundate relief agencies, such as Save the Children, with donations, and to bring global attention to the crisis in Ethiopia. The news report was also watched by Bob Geldof, who would organise the charity single "Do They Know It's Christmas?" to raise money for famine relief followed by the Live Aid concert in July 1985. Starting in 1981, the BBC gave a common theme to its main news bulletins with new electronic titles–a set of computer-animated "stripes" forming a circle on a red background with a "BBC News" typescript appearing below the circle graphics, and a theme tune consisting of brass and keyboards. The Nine used a similar (striped) number 9. The red background was replaced by a blue from 1985 until 1987. By 1987, the BBC had decided to re-brand its bulletins and established individual styles again for each one with differing titles and music, the weekend and holiday bulletins branded in a similar style to the Nine, although the "stripes" introduction continued to be used until 1989 on occasions where a news bulletin was screened out of the running order of the schedule. In 1987, John Birt resurrected the practice of correspondents working for both TV and radio with the introduction of bi-media journalism. During the 1990s, a wider range of services began to be offered by BBC News, with the split of BBC World Service Television to become BBC World (news and current affairs), and BBC Prime (light entertainment). Content for a 24-hour news channel was thus required, followed in 1997 with the launch of domestic equivalent BBC News 24. Rather than set bulletins, ongoing reports and coverage was needed to keep both channels functioning and meant a greater emphasis in budgeting for both was necessary. In 1998, after 66 years at Broadcasting House, the BBC Radio News operation moved to BBC Television Centre. New technology, provided by Silicon Graphics, came into use in 1993 for a re-launch of the main BBC 1 bulletins, creating a virtual set which appeared to be much larger than it was physically. The relaunch also brought all bulletins into the same style of set with only small changes in colouring, titles, and music to differentiate each. A computer generated cut-glass sculpture of the BBC coat of arms was the centrepiece of the programme titles until the large scale corporate rebranding of news services in 1999. In November 1997, BBC News Online was launched, following individual webpages for major news events such as the 1996 Olympic Games, 1997 general election, and the death of Princess Diana. In 1999, the biggest relaunch occurred, with BBC One bulletins, BBC World, BBC News 24, and BBC News Online all adopting a common style. One of the most significant changes was the gradual adoption of the corporate image by the BBC regional news programmes, giving a common style across local, national and international BBC television news. This also included Newyddion, the main news programme of Welsh language channel S4C, produced by BBC News Wales. Following the relaunch of BBC News in 1999, regional headlines were included at the start of the BBC One news bulletins in 2000. The English regions did however lose five minutes at the end of their bulletins, due to a new headline round-up at 18:55. 2000 also saw the Nine O'Clock News moved to the later time of 22:00. This was in response to ITN who had just moved their popular News at Ten programme to 23:00. ITN briefly returned News at Ten but following poor ratings when head-to-head against the BBC's Ten O'Clock News, the ITN bulletin was moved to 22.30, where it remained until 14 January 2008. The retirement in 2009 of Peter Sissons and departure of Michael Buerk from the Ten O'Clock News led to changes in the BBC One bulletin presenting team on 20 January 2003. The Six O'Clock News became double headed with George Alagiah and Sophie Raworth after Huw Edwards and Fiona Bruce moved to present the Ten. A new set design featuring a projected fictional newsroom backdrop was introduced, followed on 16 February 2004 by new programme titles to match those of BBC News 24. BBC News 24 and BBC World introduced a new style of presentation in December 2003, that was slightly altered on 5 July 2004 to mark 50 years of BBC Television News. On 7 March 2005 director general Mark Thompson launched the "Creative Futures" project to restructure the organisation. The individual positions of editor of the One and Six O'Clock News were replaced by a new daytime position in November 2005. Kevin Bakhurst became the first Controller of BBC News 24, replacing the position of editor. Amanda Farnsworth became daytime editor while Craig Oliver was later named editor of the Ten O'Clock News. Bulletins received new titles and a new set design in May 2006, to allow for Breakfast to move into the main studio for the first time since 1997. The new set featured Barco videowall screens with a background of the London skyline used for main bulletins and originally an image of cirrus clouds against a blue sky for Breakfast. This was later replaced following viewer criticism. The studio bore similarities with the ITN-produced ITV News in 2004, though ITN uses a CSO Virtual studio rather than the actual screens at BBC News. BBC News became part of a new BBC Journalism group in November 2006 as part of a restructuring of the BBC. The then-Director of BBC News, Helen Boaden reported to the then-Deputy Director-General and head of the journalism group, Mark Byford until he was made redundant in 2010. On 18 October 2007, ED Mark Thompson announced a six-year plan, "Delivering Creative Futures" (based on his project begun in March 2005), merging the television current affairs department into a new "News Programmes" division. Thompson's announcement, in response to a £2 billion shortfall in funding, would, he said, deliver "a smaller but fitter BBC" in the digital age, by cutting its payroll and, in 2013, selling Television Centre. The various separate newsrooms for television, radio and online operations were merged into a single multimedia newsroom. Programme making within the newsrooms was brought together to form a multimedia programme making department. BBC World Service director Peter Horrocks said that the changes would achieve efficiency at a time of cost-cutting at the BBC. In his blog, he wrote that by using the same resources across the various broadcast media meant fewer stories could be covered, or by following more stories, there would be fewer ways to broadcast them. A new graphics and video playout system was introduced for production of television bulletins in January 2007. This coincided with a new structure to BBC World News bulletins, editors favouring a section devoted to analysing the news stories reported on. The first new BBC News bulletin since the Six O'Clock News was announced in July 2007 following a successful trial in the Midlands. The summary, lasting 90 seconds, has been broadcast at 20:00 on weekdays since December 2007 and bears similarities with 60 Seconds on BBC Three, but also includes headlines from the various BBC regions and a weather summary. As part of a long-term cost cutting programme, bulletins were renamed the BBC News at One, Six and Ten respectively in April 2008 while BBC News 24 was renamed BBC News and moved into the same studio as the bulletins at BBC Television Centre. BBC World was renamed BBC World News and regional news programmes were also updated with the new presentation style, designed by Lambie-Nairn. 2008 also saw tri-media introduced across TV, radio, and online. The studio moves also meant that Studio N9, previously used for BBC World, was closed, and operations moved to the previous studio of BBC News 24. Studio N9 was later refitted to match the new branding, and was used for the BBC's UK local elections and European elections coverage in early June 2009. A strategy review of the BBC in March 2010, confirmed that having "the best journalism in the world" would form one of five key editorial policies, as part of changes subject to public consultation and BBC Trust approval. After a period of suspension in late 2012, Helen Boaden ceased to be the Director of BBC News. On 16 April 2013, incoming BBC Director-General Tony Hall named James Harding, a former editor of The Times of London newspaper as Director of News and Current Affairs. From August 2012 to March 2013, all news operations moved from Television Centre to new facilities in the refurbished and extended Broadcasting House, in Portland Place. The move began in October 2012, and also included the BBC World Service, which moved from Bush House following the expiry of the BBC's lease. This new extension to the north and east, referred to as "New Broadcasting House", includes several new state-of-the-art radio and television studios centred around an 11-storey atrium. The move began with the domestic programme The Andrew Marr Show on 2 September 2012, and concluded with the move of the BBC News channel and domestic news bulletins on 18 March 2013. The newsroom houses all domestic bulletins and programmes on both television and radio, as well as the BBC World Service international radio networks and the BBC World News international television channel. BBC News and CBS News established an editorial and newsgathering partnership in 2017, replacing an earlier long-standing partnership between BBC News and ABC News. In an October 2018 Simmons Research survey of 38 news organisations, BBC News was ranked the fourth most trusted news organisation by Americans, behind CBS News, ABC News and The Wall Street Journal. In January 2020 the BBC announced a BBC News savings target of £80 million per year by 2022, involving about 450 staff reductions from the current 6,000. BBC director of news and current affairs Fran Unsworth said there would be further moves toward digital broadcasting, in part to attract back a youth audience, and more pooling of reporters to stop separate teams covering the same news. A further 70 staff reductions were announced in July 2020. BBC Three began airing the news programme The Catch Up in February 2022. It is presented by Levi Jouavel, Kirsty Grant, and Callum Tulley and aims to get the channel's target audience (16 to 34-year olds) to make sense of the world around them while also highlighting optimistic stories. Compared to its predecessor 60 Seconds, The Catch Up is three times longer, running for about three minutes and not airing during weekends. According to its annual report as of December 2021[update], India has the largest number of people using BBC services in the world. In May 2025, following the earthquake that hit Myanmar and Thailand, a television news bulletin (BBC News Myanmar) from the Burmese service using a vacated Voice of America satellite frequency began its broadcasts. Programming and reporting In November 2023, BBC News joined with the International Consortium of Investigative Journalists, Paper Trail Media [de] and 69 media partners including Distributed Denial of Secrets and the Organised Crime and Corruption Reporting Project (OCCRP) and more than 270 journalists in 55 countries and territories to produce the 'Cyprus Confidential' report on the financial network which supports the regime of Vladimir Putin, mostly with connections to Cyprus, and showed Cyprus to have strong links with high-up figures in the Kremlin, some of whom have been sanctioned. Government officials including Cyprus president Nikos Christodoulides and European lawmakers began responding to the investigation's findings in less than 24 hours, calling for reforms and launching probes. BBC News is responsible for the news programmes and documentary content on the BBC's general television channels, as well as the news coverage on the BBC News Channel in the UK, and 22 hours of programming for the corporation's international BBC World News channel. Coverage for BBC Parliament is carried out on behalf of the BBC at Millbank Studios, though BBC News provides editorial and journalistic content. BBC News content is also output onto the BBC's digital interactive television services under the BBC Red Button brand, and until 2012, on the Ceefax teletext system. The music on all BBC television news programmes was introduced in 1999 and composed by David Lowe. It was part of the re-branding which commenced in 1999 and features 'BBC Pips'. The general theme was used on bulletins on BBC One, News 24, BBC World and local news programmes in the BBC's Nations and Regions. Lowe was also responsible for the music on Radio One's Newsbeat. The theme has had several changes since 1999, the latest in March 2013. The BBC Arabic Television news channel launched on 11 March 2008, a Persian-language channel followed on 14 January 2009, broadcasting from the Peel wing of Broadcasting House; both include news, analysis, interviews, sports and highly cultural programmes and are run by the BBC World Service and funded from a grant-in-aid from the British Foreign Office (and not the television licence). The BBC Verify service was launched in 2023 to fact-check news stories, followed by BBC Verify Live in 2025. BBC Radio News produces bulletins for the BBC's national radio stations and provides content for local BBC radio stations via the General News Service (GNS), a BBC-internal news distribution service. BBC News does not produce the BBC's regional news bulletins, which are produced individually by the BBC nations and regions themselves. The BBC World Service broadcasts to some 150 million people in English as well as 27 languages across the globe. BBC Radio News is a patron of the Radio Academy. BBC News Online is the BBC's news website. Launched in November 1997, it is one of the most popular news websites, with 1.2 billion website visits in April 2021, as well as being used by 60% of the UK's internet users for news. The website contains international news coverage as well as entertainment, sport, science, and political news. Mobile apps for Android, iOS and Windows Phone systems have been provided since 2010. Many television and radio programmes are also available to view on the BBC iPlayer and BBC Sounds services. The BBC News channel is also available to view 24 hours a day, while video and radio clips are also available within online news articles. In October 2019, BBC News Online launched a mirror on the dark web anonymity network Tor in an effort to circumvent censorship. Criticism The BBC is required by its charter to be free from both political and commercial influence and answers only to its viewers and listeners. This political objectivity is sometimes questioned. For instance, The Daily Telegraph (3 August 2005) carried a letter from the KGB defector Oleg Gordievsky, referring to it as "The Red Service". Books have been written on the subject, including anti-BBC works like Truth Betrayed by W J West and The Truth Twisters by Richard Deacon. The BBC has been accused of bias by Conservative MPs. The BBC's Editorial Guidelines on Politics and Public Policy state that while "the voices and opinions of opposition parties must be routinely aired and challenged", "the government of the day will often be the primary source of news". The BBC is regularly accused by the government of the day of bias in favour of the opposition and, by the opposition, of bias in favour of the government. Similarly, during times of war, the BBC is often accused by the UK government, or by strong supporters of British military campaigns, of being overly sympathetic to the view of the enemy. An edition of Newsnight at the start of the Falklands War in 1982 was described as "almost treasonable" by John Page, MP, who objected to Peter Snow saying "if we believe the British". During the first Gulf War, critics of the BBC took to using the satirical name "Baghdad Broadcasting Corporation". During the Kosovo War, the BBC were labelled the "Belgrade Broadcasting Corporation" (suggesting favouritism towards the FR Yugoslavia government over ethnic Albanian rebels) by British ministers, although Slobodan Milosević (then FRY president) claimed that the BBC's coverage had been biased against his nation. Conversely, some of those who style themselves anti-establishment in the United Kingdom or who oppose foreign wars have accused the BBC of pro-establishment bias or of refusing to give an outlet to "anti-war" voices. Following the 2003 invasion of Iraq, a study by the Cardiff University School of Journalism of the reporting of the war found that nine out of 10 references to weapons of mass destruction during the war assumed that Iraq possessed them, and only one in 10 questioned this assumption. It also found that, out of the main British broadcasters covering the war, the BBC was the most likely to use the British government and military as its source. It was also the least likely to use independent sources, like the Red Cross, who were more critical of the war. When it came to reporting Iraqi casualties, the study found fewer reports on the BBC than on the other three main channels. The report's author, Justin Lewis, wrote "Far from revealing an anti-war BBC, our findings tend to give credence to those who criticised the BBC for being too sympathetic to the government in its war coverage. Either way, it is clear that the accusation of BBC anti-war bias fails to stand up to any serious or sustained analysis." Prominent BBC appointments are constantly assessed by the British media and political establishment for signs of political bias. The appointment of Greg Dyke as Director-General was highlighted by press sources because Dyke was a Labour Party member and former activist, as well as a friend of Tony Blair. The BBC's former Political Editor, Nick Robinson, was some years ago a chairman of the Young Conservatives and did, as a result, attract informal criticism from the former Labour government, but his predecessor Andrew Marr faced similar claims from the right because he was editor of The Independent, a liberal-leaning newspaper, before his appointment in 2000. Mark Thompson, former Director-General of the BBC, admitted the organisation has been biased "towards the left" in the past. He said, "In the BBC I joined 30 years ago, there was, in much of current affairs, in terms of people's personal politics, which were quite vocal, a massive bias to the left". He then added, "The organization did struggle then with impartiality. Now it is a completely different generation. There is much less overt tribalism among the young journalists who work for the BBC." Following the EU referendum in 2016, some critics suggested that the BBC was biased in favour of leaving the EU. For instance, in 2018, the BBC received complaints from people who took issue that the BBC was not sufficiently covering anti-Brexit marches while giving smaller-scale events hosted by former UKIP leader Nigel Farage more airtime. On the other hand, a poll released by YouGov showed that 45% of people who voted to leave the EU thought that the BBC was 'actively anti-Brexit' compared to 13% of the same kinds of voters who think the BBC is pro-Brexit. In 2008, the BBC Hindi was criticised by some Indian outlets for referring to the terrorists who carried out the 2008 Mumbai attacks as "gunmen". The response to this added to prior criticism from some Indian commentators suggesting that the BBC may have an Indophobic bias. In March 2015, the BBC was criticised for a BBC Storyville documentary interviewing one of the rapists in India. In spite of a ban ordered by the Indian High court, the BBC still aired the documentary "India's Daughter" outside India. BBC News was at the centre of a political controversy following the 2003 invasion of Iraq. Three BBC News reports (Andrew Gilligan's on Today, Gavin Hewitt's on The Ten O'Clock News and another on Newsnight) quoted an anonymous source that stated the British government (particularly the Prime Minister's office) had embellished the September Dossier with misleading exaggerations of Iraq's weapons of mass destruction capabilities. The government denounced the reports and accused the corporation of poor journalism. In subsequent weeks the corporation stood by the report, saying that it had a reliable source. Following intense media speculation, David Kelly was named in the press as the source for Gilligan's story on 9 July 2003. Kelly was found dead, by suicide, in a field close to his home early on 18 July. An inquiry led by Lord Hutton was announced by the British government the following day to investigate the circumstances leading to Kelly's death, concluding that "Dr. Kelly took his own life." In his report on 28 January 2004, Lord Hutton concluded that Gilligan's original accusation was "unfounded" and the BBC's editorial and management processes were "defective". In particular, it specifically criticised the chain of management that caused the BBC to defend its story. The BBC Director of News, Richard Sambrook, the report said, had accepted Gilligan's word that his story was accurate in spite of his notes being incomplete. Davies had then told the BBC Board of Governors that he was happy with the story and told the Prime Minister that a satisfactory internal inquiry had taken place. The Board of Governors, under the chairman's, Gavyn Davies, guidance, accepted that further investigation of the Government's complaints were unnecessary. Because of the criticism in the Hutton report, Davies resigned on the day of publication. BBC News faced an important test, reporting on itself with the publication of the report, but by common consent (of the Board of Governors) managed this "independently, impartially and honestly". Davies' resignation was followed by the resignation of Director General, Greg Dyke, the following day, and the resignation of Gilligan on 30 January. While undoubtedly a traumatic experience for the corporation, an ICM poll in April 2003 indicated that it had sustained its position as the best and most trusted provider of news. The BBC has faced accusations of holding both anti-Israel and anti-Palestine bias. Douglas Davis, the London correspondent of The Jerusalem Post, has described the BBC's coverage of the Arab–Israeli conflict as "a relentless, one-dimensional portrayal of Israel as a demonic, criminal state and Israelis as brutal oppressors [which] bears all the hallmarks of a concerted campaign of vilification that, wittingly or not, has the effect of delegitimising the Jewish state and pumping oxygen into a dark old European hatred that dared not speak its name for the past half-century.". However two large independent studies, one conducted by Loughborough University and the other by Glasgow University's Media Group concluded that Israeli perspectives are given greater coverage. Critics of the BBC argue that the Balen Report proves systematic bias against Israel in headline news programming. The Daily Mail and The Daily Telegraph criticised the BBC for spending hundreds of thousands of British tax payers' pounds from preventing the report being released to the public. Jeremy Bowen, the Middle East Editor for BBC world news, was singled out specifically for bias by the BBC Trust which concluded that he violated "BBC guidelines on accuracy and impartiality." An independent panel appointed by the BBC Trust was set up in 2006 to review the impartiality of the BBC's coverage of the Israeli–Palestinian conflict. The panel's assessment was that "apart from individual lapses, there was little to suggest deliberate or systematic bias." While noting a "commitment to be fair accurate and impartial" and praising much of the BBC's coverage the independent panel concluded "that BBC output does not consistently give a full and fair account of the conflict. In some ways the picture is incomplete and, in that sense, misleading." It notes that, "the failure to convey adequately the disparity in the Israeli and Palestinian experience, [reflects] the fact that one side is in control and the other lives under occupation". Writing in the Financial Times, Philip Stephens, one of the panellists, later accused the BBC's director-general, Mark Thompson, of misrepresenting the panel's conclusions. He further opined "My sense is that BBC news reporting has also lost a once iron-clad commitment to objectivity and a necessary respect for the democratic process. If I am right, the BBC, too, is lost". Mark Thompson published a rebuttal in the FT the next day. The description by one BBC correspondent reporting on the funeral of Yassir Arafat that she had been left with tears in her eyes led to other questions of impartiality, particularly from Martin Walker in a guest opinion piece in The Times, who picked out the apparent case of Fayad Abu Shamala, the BBC Arabic Service correspondent, who told a Hamas rally on 6 May 2001, that journalists in Gaza were "waging the campaign shoulder to shoulder together with the Palestinian people". Walker argues that the independent inquiry was flawed for two reasons. Firstly, because the time period over which it was conducted (August 2005 to January 2006) surrounded the Israeli withdrawal from Gaza and Ariel Sharon's stroke, which produced more positive coverage than usual. Furthermore, he wrote, the inquiry only looked at the BBC's domestic coverage, and excluded output on the BBC World Service and BBC World. Tom Gross accused the BBC of glorifying Hamas suicide bombers, and condemned its policy of inviting guests such as Jenny Tonge and Tom Paulin who have compared Israeli soldiers to Nazis. Writing for the BBC, Paulin said Israeli soldiers should be "shot dead" like Hitler's S.S, and said he could "understand how suicide bombers feel". The BBC also faced criticism for not airing a Disasters Emergency Committee aid appeal for Palestinians who suffered in Gaza during 22-day war there between late 2008 and early 2009. Most other major UK broadcasters did air this appeal, but rival Sky News did not. British journalist Julie Burchill has accused BBC of creating a "climate of fear" for British Jews over its "excessive coverage" of Israel compared to other nations. In light of the Gaza war, the BBC suspended seven Arab journalists over allegations of expressing support for Hamas via social media. BBC and ABC share video segments and reporters as needed in producing their newscasts. with the BBC showing ABC World News Tonight with David Muir in the UK. However, in July 2017, the BBC announced a new partnership with CBS News allows both organisations to share video, editorial content, and additional newsgathering resources in New York, London, Washington and around the world. BBC News subscribes to wire services from leading international agencies including PA Media (formerly Press Association), Reuters, and Agence France-Presse. In April 2017, the BBC dropped Associated Press in favour of an enhanced service from AFP. BBC News reporters and broadcasts are now and have in the past been banned in several countries primarily for reporting which has been unfavourable to the ruling government. For example, correspondents were banned by the former apartheid regime of South Africa. The BBC was banned in Zimbabwe under Mugabe for eight years as a terrorist organisation until being allowed to operate again over a year after the 2008 elections. The BBC was banned in Burma (officially Myanmar) after their coverage and commentary on anti-government protests there in September 2007. The ban was lifted four years later in September 2011. Other cases have included Uzbekistan, China, and Pakistan. BBC Persian, the BBC's Persian language news site, was blocked from the Iranian internet in 2006. The BBC News website was made available in China again in March 2008, but as of October 2014[update], was blocked again. In June 2015, the Rwandan government placed an indefinite ban on BBC broadcasts following the airing of a controversial documentary regarding the 1994 Rwandan genocide, Rwanda's Untold Story, broadcast on BBC2 on 1 October 2014. The UK's Foreign Office recognised "the hurt caused in Rwanda by some parts of the documentary". In February 2017, reporters from the BBC (as well as the Daily Mail, The New York Times, Politico, CNN, and others) were denied access to a United States White House briefing. In 2017, BBC India was banned for a period of five years from covering all national parks and sanctuaries in India. Following the withdrawal of CGTN's UK broadcaster licence on 4 February 2021 by Ofcom, China banned BBC News from airing in China. See also References External links \|below = Category }}
========================================

[SOURCE: https://www.theverge.com/podcast/879203/ring-search-party-super-bowl-ai-surveillance-privacy-security] \| [TOKENS: 11410]
PodcastsClosePodcastsPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PodcastsAICloseAIPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All AITechCloseTechPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All TechLet’s talk about Ring, lost dogs, and the surveillance stateThe security camera maker’s Search Party feature, advertised during the Super Bowl, has sparked a surveillance backlash.by Nilay PatelCloseNilay PatelEditor-in-ChiefPosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by Nilay PatelFeb 16, 2026, 3:00 PM UTCLinkShareNilay PatelCloseNilay PatelPosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by Nilay Patel is editor-in-chief of The Verge, host of the Decoder podcast, and co-host of The Vergecast.Today, let’s talk about the camera company Ring, lost dogs, and the surveillance state.You probably saw this ad during the Super Bowl a couple of weekends ago:Since it aired for a massive audience at the Super Bowl, Ring’s Search Party commercial has become a lightning rod for controversy — it’s easy to see how the same technology that can find lost dogs can be used to find people, and then used to invade our privacy in all kinds of uncomfortable ways, by cops and regular people alike.Ring in particular has always been proud of its cooperation with law enforcement. That raises big questions about our civil rights, especially since Ring announced a partnership last fall with a company called Flock Safety, whose systems have been accessed by ICE. There’s some complication to that — we’ll come back to it in a bit. The backlash to Ring’s Super Bowl ad was swift, intense, and effective: the data company PeakMetrics says conversation about the ad on social platforms like X actually peaked two days after the Super Bowl, and the vibes, as they measured them, were strikingly negative. I mean, you know it’s bad when Matt Nelson, who runs the weratedogs account, is posting videos like this:Sen. Ed Markey called the ad “dystopian” and said it was proof Amazon, which owns Ring, needed to cease all facial recognition technology on Ring doorbells. He said, “This definitely isn’t about dogs — it’s about mass surveillance.”And then, on Thursday, February 12th, just four days after the Super Bowl, Ring announced it was canceling its partnership with Flock, in a statement first reported by The Verge’s Jen Tuohy. That statement itself is a lot:Following a comprehensive review, we determined the planned Flock Safety integration would require significantly more time and resources than anticipated. As a result, we have made the joint decision to cancel the planned integration. The integration never launched, so no Ring customer videos were ever sent to Flock Safety.The company also goes on to say that Ring cameras were used by police in identifying a school shooter at Brown University in December 2025. It’s an odd non sequitur in a press release about canceling a controversial partnership that really explains a lot about Ring, and how the company sees itself.As it happens, Ring’s founder Jamie Siminoff was just on Decoder a few months ago, talking about how and why he founded the company, and in detail about why he sees Ring’s mission as eliminating crime. Not selling cameras or doorbells, or floodlights, or anything else Ring makes, but getting rid of crime.We actually talked about Search Party and how people might feel about that kind of surveillance, and how Ring works with the cops quite a bit. In fact, Jamie briefly left Ring in 2023, and the company slowed down on its work with law enforcement. But ever since he returned, the emphasis on crime and the work with police has only intensified. I asked him about it:NILAY PATEL: You left, Amazon said we’re going to stop working with police, you came back, boy, Ring is going to work with police again. You have a partnership with Axon, which makes the taser, that allows law enforcement to get access to Ring footage. Did that feel like a two-way door? They made the wrong decision in your absence, and you came back and said, “We’re going to do this again”?JAMIE SIMINOFF: I don’t know if it’s wrong or right, but I think different leadership does different things. I do believe that I spent a lot of time going on ride-alongs. I spent a lot of time in areas that I’d say are not safe for those people, and I’ve seen a lot of things where I think we can positively impact them. So, we don’t work with police in the way of ... I just want to be careful, as we’re not ... What we do allow is for agencies to ask for footage when something happens. We allow our neighbors, which I’ll say in this point are our customers, just to be clear, we allow our customers to anonymously decide whether or not they want to partake in that.So, if they decide they don’t want to be part of this network and don’t want to help this public service agency that asks them, they just say no. If they decide that they do want to, which, by the way, a lot of people want to increase the security of their neighborhoods. A lot of people want their kids to grow up in safer neighborhoods, a lot of people want to have the tools to do that, and are in places that are dangerous. We give them the ability to say yes and make it more efficient for them to communicate with those public service agencies, and also do it in a very auditable digital format.That’s the other side. Today, without these tools, if a police officer wanted to go and get footage from something, they’d have to go and knock on the door and ask you, and that’s not comfortable for anyone. There’s no digital audit trail of it, and, with this, they can do it efficiently with an audit trail. It is very clear, and it’s anonymous.Jamie actually talked a lot about searching for dogs in this context, because one of the reasons he was so excited to come back to Ring was to use AI to search through the massive amounts of video generated by Ring cameras. In fact, he told me that Ring could not have built Search Party five years ago, because AI systems to do it weren’t available.Jamie is nothing if not direct about this, which I appreciate. The man really thinks you can use AI and cameras to reduce or even eliminate crime. But I had a lot of questions about this:JAIME SIMINOFF: But when you put AI into it, now, all of a sudden, you have this human element that AI gives you. I think, with our products in neighborhoods and, again, you have to be a little bit specific to it, I do see a path where we can actually start to take down crime in a neighborhood to call it close to zero. And I even said, there are some crimes that you can’t stop, of course.NILAY PATEL: Mechanically, walk people through what you mean. You put enough Ring products in a neighborhood, and then AI does what to them that helps you get closer to the mission of zeroing out crime?So, the mental model, or how I look at it, is that AI allows us to have ... If you had a neighborhood where you had unlimited resources, so every house had security guards and those security guards were people that worked the same house for 10 years or 20 years, and I mean that from a knowledge perspective. So, the knowledge they had of that house was extreme; they knew everything about you and that residence and your family, how you lived, the people that came in and out.And then, if that neighborhood had an HOA with, call it private security, and those private security were also around and knew everything, what would happen? When a dog gets lost, you’d be like, “Oh, my gosh, my dog is lost.” Well, they would call each other, and one of them would find the dog very quickly. So, how do we change that and bring that into the digital world is—Can I just ask you a question about that neighborhood specifically?Sure.Do you ever stop and consider that that neighborhood might suck? Just the idea that every house on my street would have all-knowing private security guards, and I would have an HOA, and that HOA would have a private security force. You can easily paint that as dystopia. Everyone’s so afraid that we have private cops on every corner, and I’m paying HOA fees, which is just a nightmare of its own.So, I would assume you live in a safe neighborhood.I hope so, yeah.No, today, I’d go to ... If you want, I’ll take you to a place where people live and have to, when they get home from school, lock their doors and stay in their house, and they can’t go out and—But I’m just saying that that model is “everybody is so afraid that they have private cops.”I think the model is that doing crime in a neighborhood like that is not profitable, and I think that you want people to move into another job. I don’t think that crime is a good thing and so I think ... But listen, it certainly is an argument to have, I do believe that ... I think safer neighborhoods allow for kids to grow up in a better environment and I think that allows them to be able to focus on the things that matter and so that’s what we’re going for.I just wanted to challenge the premise.I think it’s a fair challenge.The model is that there are cops everywhere. That level of privacy.Yeah, it’s not cops. I think it’s more that you’ll have the ability to understand what’s happening. It’s not like ... But yeah, I think, listen, it’s a fair statement, I guess. I think I want to live in a safe place.There’s a lot of intelligence in your neighborhood, and maybe it’s private security, maybe it’s not. What does the AI do? Does it just make the camera smarter? It lets you do a more intelligent assessment of what the cameras are seeing?Right now, we just say motion detection, motion detection, motion detection. It’s funny, when I started Ring… The book was fun because I got to go back and actually go through this whole story of how this thing came to be, and motion detection was an amazing invention. You’re in the airport, and there’s a motion at your front door, and you look at it like, “Wow, this is crazy.”Now, with AI, we shouldn’t be telling you about motion detection; we should be telling you what’s there, when you should look at it, when it matters, and we shouldn’t be bothering you all the time. That’s what I mean by this idea of these security guards at your house or in your neighborhood. There should be this intelligence in your neighborhood that can tell you when you should be trying to be part of something, but not always tell you. So, it’s not just like, “Car, car, dog, person, person.” It’s like, “Hey, look at this. You want to pay attention to this right now.”I really pressed Jamie on this because I still don’t think it is entirely clear how Ring accomplishes the elimination of crime through AI alone. And it’s why people don’t trust the company when it says it won’t use systems that can find a dog to do things that otherwise violate our rights. After all, if your goal is to use AI to stop crime, and you built an AI system that can find a dog… well, it’s pretty obvious what comes next, right?NILAY PATEL: Do you think when you talk about zero out crime in a neighborhood, the idea that everyone in a neighborhood has one of those illuminated Ring signs in the front yard, is that enough to—JAMIE SIMINOFF: It’s a part of it.Is that just enough of a deterrent? The bad guys will know their face is going to be captured on video, and that will be analyzed by an AI, and something will happen. Do you have to do more outbound deterrents?I think that’s a part of it. Awareness is a big part of it. I think there are ways with lights also, using lighting to do stuff, that’s a big part of it. I think having just ... If, all of a sudden, someone comes outside because something’s an anomaly, that’s a big part of it. It doesn’t have to be some crazy thing. And that’s what I was saying, is a lot of these little things add up to make that work.So, when you think about it, okay, we can bring crime down in a neighborhood to close to zero in a neighborhood, what are the ratcheting steps? Does everyone just get the Ring camera, and your platform does all the work? Is it that someone gets caught and they tell all their friends in jail that they got caught? What are the steps?I think it’s really about bringing neighbors together for this particular thing. So, it’s about how you individually… and we’ve always thought about how each house is its own node controlled by the neighbors, so controlled by the person, and I’ll keep going back to that, which is one hundred percent, your video is in your control; everything you’re doing is in your control, whether you want to take part in anything is in your control. That has to be the first layer of all of it.But then, when something happens, do you want to take part in it? So, if you get an alert that this dog looks like the dog that’s in front of your house, can you contact your neighbor? You can decide not to take part in it, and then no one will ever know, and it’s fine, it’s just basically deleted, or you can take part in it. I think that’s how we can do things that can make a neighborhood into this node where individual neighbors are all on their own, but when things happen, they can work together as they want to.And you think that AI will accelerate the process? I think AI is a co-pilot. It is their assistant, and it’s helping them to figure this out. Because, again, if you’re just getting every motion alert, and if you have eight cameras and you’re just getting motion alerts all day, no human being can parse all this data. So that’s what I was talking to Jen about, is that I do think I see a way to use AI to help feed better data to us, which allows us to make better decisions and work together better.Image: The VergeThis is where we get to Flock, which Ring announced a partnership with in October 2025. Flock primarily makes cameras and systems to search video for the cops. You’ve probably seen Flock’s devices where you live — they’re those little solar-powered cameras and tracking devices affixed to streetlights or placed in the center of parking lots. They vacuum up large amounts of data, and the company claims it is anonymized before it’s made available to partners, which in most cases is local law enforcement.However, according to in-depth reporting from the excellent 404 Media, Flock’s data has often found its way to ICE, the FBI, the Secret Service, and other law enforcement agencies, without the requirement of a warrant. That’s because that data is willingly provided by local police.Last month, under intense scrutiny about what a deal with Flock would mean, Ring said that this partnership was not yet “live,” and that, “Ring has no partnership with ICE, does not give ICE videos, feeds, or back-end access, and does not share video with them.” For its part, Flock says the same — that it doesn’t actually work with ICE, but rather local law enforcement, and it’s those local agencies that work with ICE. This is the complication I mentioned earlier.If you’re a Decoder listener, you know where this is all going. I asked Jamie about all these databases, who owns them, and what it means to connect them all with AI:NILAY PATEL: But when you connect a bunch of those databases, particularly to facial recognition, there’s a turn in the privacy conversation where the stakes ratchet up really high, where maybe it’s gone forever. How are you thinking about that decision-making? Okay, we have a lot of intelligence in the AI; it’s trivial for the AI to connect to another store of information. That’s a thing you can do with AI, especially at a big company like Amazon, where you have lots of other stores of information. There’s a line, what’s the line for you?JAMIE SIMINOFF: There is a responsibility, obviously just to build safe products. So let’s just start with that. Yeah, we did announce facial, we call it Familiar Faces, but that’s not connected, that’s just for your... Your iPhone today. If you search your iPhone, it’s crazy. Search for someone’s name in your photos, and their pictures come up.So I do think there’s a balance between not allowing technology to exist that should exist that helps people and gives them more efficiency, gives them safer homes and then also, obviously, not creating this dystopian place. And so, I think that’s the responsibility, but what we’re doing with Familiar Faces is we’re just giving you the ability to say, when my wife comes home, don’t... Because it is silly. Why do I get an alert when my wife comes home? I don’t want it, I don’t need it.I’m asking this for a lot of reasons, but I look at what’s broadly happening with surveillance footage out in the world. And I’m not saying Ring is participating in this, I’m just giving you an example. ICE has facial recognition systems, and they are arguing that a positive match in their facial recognition system is a definitive determination of someone’s immigration status. That’s way out there. I don’t think you’re doing that.But you can get to, “Okay, we have facial recognition, we have a bunch of evidence coming off of Ring cameras, to make it really safe, you want to go from passive surveillance to active surveillance. That’s what the studies show. Now the camera will literally identify the criminal by face and tell the cops this person tried to steal a car from this driveway,” and that’s the thing that would get you to actually zero out crime.There’s a lot of risk in those steps. But if I draw the thread from what you’re saying, it’s all the way to the idea that the criminals won’t come here because the cameras will know who they are and tell the cops. Are you willing to go that far?I think it’s also that the cameras will alert people. Part of what made Ring and what made neighbors safer with Ring 1.0, and I think we are in Ring 2.0, is that there was no presence at the home. How did people break into homes? They would go and be knock-knock burglars. They would knock-knock, no one was home. It was 3PM, they’d go to the homes next door, find a place that was empty, and they’d go into the home.Ring allowed you to, now, all of a sudden, when someone comes up to the door, you’re like, “Oh, I got a motion alert. Hi, what’s going on?” and so it gave a presence to the home. So, I don’t think you have to go as far as that real time stuff to get to where we’re talking about, I think it’s more of the anomaly detection and allowing people to make it so that, if someone comes in, that you’re aware of what’s happening around the neighborhood because right now there’s no awareness of what’s going on around it.So I don’t think it’s as dystopian as where you’re going, and certainly it’s not what we’re building, and I do think we can impact things to a really high level in neighborhoods. Which, again, to the Jen Tuohy thing, in neighborhoods is what we were talking about, that with AI and what we’re doing with a bunch of Rings together. I think even the Dog Search Party is a good way to look at it, which is how these cameras come together for good in the neighborhood.Today, the backlash against surveillance has led Ring to kill that Flock deal. The company is also doing damage control about Search Party, telling The Verge that the technology that powers the feature is not “capable” of being used to find people, and that there’s no indication that such features are on future road maps.Sure, it seems obvious that Ring has a lot of trust to earn back here, and certainly, we are all thinking about what it means to put internet-connected security cameras in our homes. I think that’s good — and certainly overdue.But let me complicate this a little for you. At the same time this conversation about Ring is happening, we’re also watching regular people record the police and ICE with their cell phones, capturing critical documentary evidence of how those agencies are violating the rights of everyday Americans in ways that is leading to change, however slow.Minnesota governor Tim Walz is now telling people to hit record when they see ICE so the footage can be used in future prosecutions. And just last week, the FBI released video that Google appears to have specifically recovered from a Nest camera system at Nancy Guthrie’s house, in order to help identify her kidnapper.That’s a lot of video that’s being captured and used in ways that maybe don’t feel so invasive, and in some cases even feels good. But the systems that create, store, and share that video are all the same, and the guardrails around them are just as weak as whatever makes us feel uncomfortable about Ring.I’m not sure how to feel about all of that video, especially in a world where AI makes it easy to fake, and having some source of truth seems more important than ever. I asked Jamie about that, too — whether Ring will control all the video, or sign it with some metadata so people can ensure it’s real.NILAY PATEL: Presuming we have to have an authenticated server, there’s a crime in my neighborhood, and I’ve opted in, and we’re going to say the cops can only get the video from the Ring server, where we know it’s true. I might not be as in control of my video anymore.JAMIE SIMINOFF: No, not how it’s built and not while I’m here because the way it works is that you will decide if you want to or not want to share that video, which is your property, with someone. Now, once you share it, then it is up to us to figure out, to your point, how do we share it, how do we make sure that the digital fingerprint goes all the way through, or how does the chain of custody work of this video to make sure there’s no fake in the process of it? I think this is why it is important to build these systems.It’s going to be important, though. This is also where the government is going to have to step in. We’re going to have to deal with this across the board because we also have video coming off of cell phones. So, we do need to figure out how to build... And there’s going to be companies, Axon would probably be one of the companies. I don’t want to speak for them, but they have evidence.com, so to build these evidentiary systems to take in…Because Ring is one part of taking in data around, call it a crime scene, but cell phone video is maybe even more of a source today. So, how do you take that in? How do you make sure that it actually was captured on the iPhone directly and not tampered with between the two things? We’re going to have to figure it all out. I think we have to work together on it, and the AI stuff is pushing us to do it. I am proud that with Ring, we have built it so that you can take it directly and keep it on the server. You can understand where it was, where it’s from, where it was created, and we have that digital fingerprint on it and the audit trail of it.You’re going to have to do that more and more as this world is changing, you’re just not going to be able to trust that just because someone sends you a video doesn’t mean it’s true.You get the feeling we’ll be coming back to that idea quite a lot in the years to come.But today Ring has canceled its deal with Flock, and Flock itself is putting out blog posts flatly stating it does not have a contract with ICE, and noting that Ring’s other partner, Axon, does in fact have an ICE contract.In the meantime, Search Party is still active and on by default, although you can just go into settings and flip it off. And the enormous amount of video we all generate is being uploaded to servers run by big companies that have their own dealings with governments and law enforcement agencies far outside of our control.There are a lot of solutions to all these problems, and lots of ways to design regulations to balance out privacy and civil liberties with the needs of police. But right now, in 2026 America, I’m not sure were really going to be able to do that.So we’re going to keep pushing the leaders of these companies on what they really mean, and keep running the answers so you can listen and decide. I think it’s about time we started thinking about how all the technology we use to make our own lives better affects other people.Because that bigger conversation we need to have? Yeah, that’s what it’s really about.Questions or comments about this episode? Hit us up at decoder@theverge.com. We really do read every email!Decoder with Nilay PatelA podcast from The Verge about big ideas and other problems.SUBSCRIBE NOW!Follow topics and authors from this story to see more like this in your personalized homepage feed and to receive email updates.Nilay PatelCloseNilay PatelEditor-in-ChiefPosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by Nilay PatelAICloseAIPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All AIAmazonCloseAmazonPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All AmazonDecoderCloseDecoderPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All DecoderPodcastsClosePodcastsPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PodcastsPrivacyClosePrivacyPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PrivacyTechCloseTechPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All TechMost PopularMost PopularThe RAM shortage is coming for everything you care aboutXbox chief Phil Spencer is leaving MicrosoftA $10K+ bounty is waiting for anyone who can unplug Ring doorbells from Amazon’s cloudRead new Microsoft gaming CEO Asha Sharma’s memo on the future of XboxAmazon blames human employees for an AI coding agent’s mistakeThe Verge DailyA free daily digest of the news that matters most.Email (required)Sign UpBy submitting your email, you agree to our Terms and Privacy Notice. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.Advertiser Content FromThis is the title for the native ad Posts from this topic will be added to your daily email digest and your homepage feed. See All Podcasts Posts from this topic will be added to your daily email digest and your homepage feed. See All AI Posts from this topic will be added to your daily email digest and your homepage feed. See All Tech Let’s talk about Ring, lost dogs, and the surveillance state The security camera maker’s Search Party feature, advertised during the Super Bowl, has sparked a surveillance backlash. Posts from this author will be added to your daily email digest and your homepage feed. See All by Nilay Patel Posts from this author will be added to your daily email digest and your homepage feed. See All by Nilay Patel Today, let’s talk about the camera company Ring, lost dogs, and the surveillance state. You probably saw this ad during the Super Bowl a couple of weekends ago: Since it aired for a massive audience at the Super Bowl, Ring’s Search Party commercial has become a lightning rod for controversy — it’s easy to see how the same technology that can find lost dogs can be used to find people, and then used to invade our privacy in all kinds of uncomfortable ways, by cops and regular people alike. Ring in particular has always been proud of its cooperation with law enforcement. That raises big questions about our civil rights, especially since Ring announced a partnership last fall with a company called Flock Safety, whose systems have been accessed by ICE. There’s some complication to that — we’ll come back to it in a bit. The backlash to Ring’s Super Bowl ad was swift, intense, and effective: the data company PeakMetrics says conversation about the ad on social platforms like X actually peaked two days after the Super Bowl, and the vibes, as they measured them, were strikingly negative. I mean, you know it’s bad when Matt Nelson, who runs the weratedogs account, is posting videos like this: Sen. Ed Markey called the ad “dystopian” and said it was proof Amazon, which owns Ring, needed to cease all facial recognition technology on Ring doorbells. He said, “This definitely isn’t about dogs — it’s about mass surveillance.” And then, on Thursday, February 12th, just four days after the Super Bowl, Ring announced it was canceling its partnership with Flock, in a statement first reported by The Verge’s Jen Tuohy. That statement itself is a lot: Following a comprehensive review, we determined the planned Flock Safety integration would require significantly more time and resources than anticipated. As a result, we have made the joint decision to cancel the planned integration. The integration never launched, so no Ring customer videos were ever sent to Flock Safety. The company also goes on to say that Ring cameras were used by police in identifying a school shooter at Brown University in December 2025. It’s an odd non sequitur in a press release about canceling a controversial partnership that really explains a lot about Ring, and how the company sees itself. As it happens, Ring’s founder Jamie Siminoff was just on Decoder a few months ago, talking about how and why he founded the company, and in detail about why he sees Ring’s mission as eliminating crime. Not selling cameras or doorbells, or floodlights, or anything else Ring makes, but getting rid of crime. We actually talked about Search Party and how people might feel about that kind of surveillance, and how Ring works with the cops quite a bit. In fact, Jamie briefly left Ring in 2023, and the company slowed down on its work with law enforcement. But ever since he returned, the emphasis on crime and the work with police has only intensified. I asked him about it: NILAY PATEL: You left, Amazon said we’re going to stop working with police, you came back, boy, Ring is going to work with police again. You have a partnership with Axon, which makes the taser, that allows law enforcement to get access to Ring footage. Did that feel like a two-way door? They made the wrong decision in your absence, and you came back and said, “We’re going to do this again”? JAMIE SIMINOFF: I don’t know if it’s wrong or right, but I think different leadership does different things. I do believe that I spent a lot of time going on ride-alongs. I spent a lot of time in areas that I’d say are not safe for those people, and I’ve seen a lot of things where I think we can positively impact them. So, we don’t work with police in the way of ... I just want to be careful, as we’re not ... What we do allow is for agencies to ask for footage when something happens. We allow our neighbors, which I’ll say in this point are our customers, just to be clear, we allow our customers to anonymously decide whether or not they want to partake in that. So, if they decide they don’t want to be part of this network and don’t want to help this public service agency that asks them, they just say no. If they decide that they do want to, which, by the way, a lot of people want to increase the security of their neighborhoods. A lot of people want their kids to grow up in safer neighborhoods, a lot of people want to have the tools to do that, and are in places that are dangerous. We give them the ability to say yes and make it more efficient for them to communicate with those public service agencies, and also do it in a very auditable digital format. That’s the other side. Today, without these tools, if a police officer wanted to go and get footage from something, they’d have to go and knock on the door and ask you, and that’s not comfortable for anyone. There’s no digital audit trail of it, and, with this, they can do it efficiently with an audit trail. It is very clear, and it’s anonymous. Jamie actually talked a lot about searching for dogs in this context, because one of the reasons he was so excited to come back to Ring was to use AI to search through the massive amounts of video generated by Ring cameras. In fact, he told me that Ring could not have built Search Party five years ago, because AI systems to do it weren’t available. Jamie is nothing if not direct about this, which I appreciate. The man really thinks you can use AI and cameras to reduce or even eliminate crime. But I had a lot of questions about this: JAIME SIMINOFF: But when you put AI into it, now, all of a sudden, you have this human element that AI gives you. I think, with our products in neighborhoods and, again, you have to be a little bit specific to it, I do see a path where we can actually start to take down crime in a neighborhood to call it close to zero. And I even said, there are some crimes that you can’t stop, of course. NILAY PATEL: Mechanically, walk people through what you mean. You put enough Ring products in a neighborhood, and then AI does what to them that helps you get closer to the mission of zeroing out crime? So, the mental model, or how I look at it, is that AI allows us to have ... If you had a neighborhood where you had unlimited resources, so every house had security guards and those security guards were people that worked the same house for 10 years or 20 years, and I mean that from a knowledge perspective. So, the knowledge they had of that house was extreme; they knew everything about you and that residence and your family, how you lived, the people that came in and out. And then, if that neighborhood had an HOA with, call it private security, and those private security were also around and knew everything, what would happen? When a dog gets lost, you’d be like, “Oh, my gosh, my dog is lost.” Well, they would call each other, and one of them would find the dog very quickly. So, how do we change that and bring that into the digital world is— Can I just ask you a question about that neighborhood specifically? Sure. Do you ever stop and consider that that neighborhood might suck? Just the idea that every house on my street would have all-knowing private security guards, and I would have an HOA, and that HOA would have a private security force. You can easily paint that as dystopia. Everyone’s so afraid that we have private cops on every corner, and I’m paying HOA fees, which is just a nightmare of its own. So, I would assume you live in a safe neighborhood. I hope so, yeah. No, today, I’d go to ... If you want, I’ll take you to a place where people live and have to, when they get home from school, lock their doors and stay in their house, and they can’t go out and— But I’m just saying that that model is “everybody is so afraid that they have private cops.” I think the model is that doing crime in a neighborhood like that is not profitable, and I think that you want people to move into another job. I don’t think that crime is a good thing and so I think ... But listen, it certainly is an argument to have, I do believe that ... I think safer neighborhoods allow for kids to grow up in a better environment and I think that allows them to be able to focus on the things that matter and so that’s what we’re going for. I just wanted to challenge the premise. I think it’s a fair challenge. The model is that there are cops everywhere. That level of privacy. Yeah, it’s not cops. I think it’s more that you’ll have the ability to understand what’s happening. It’s not like ... But yeah, I think, listen, it’s a fair statement, I guess. I think I want to live in a safe place. There’s a lot of intelligence in your neighborhood, and maybe it’s private security, maybe it’s not. What does the AI do? Does it just make the camera smarter? It lets you do a more intelligent assessment of what the cameras are seeing? Right now, we just say motion detection, motion detection, motion detection. It’s funny, when I started Ring… The book was fun because I got to go back and actually go through this whole story of how this thing came to be, and motion detection was an amazing invention. You’re in the airport, and there’s a motion at your front door, and you look at it like, “Wow, this is crazy.” Now, with AI, we shouldn’t be telling you about motion detection; we should be telling you what’s there, when you should look at it, when it matters, and we shouldn’t be bothering you all the time. That’s what I mean by this idea of these security guards at your house or in your neighborhood. There should be this intelligence in your neighborhood that can tell you when you should be trying to be part of something, but not always tell you. So, it’s not just like, “Car, car, dog, person, person.” It’s like, “Hey, look at this. You want to pay attention to this right now.” I really pressed Jamie on this because I still don’t think it is entirely clear how Ring accomplishes the elimination of crime through AI alone. And it’s why people don’t trust the company when it says it won’t use systems that can find a dog to do things that otherwise violate our rights. After all, if your goal is to use AI to stop crime, and you built an AI system that can find a dog… well, it’s pretty obvious what comes next, right? NILAY PATEL: Do you think when you talk about zero out crime in a neighborhood, the idea that everyone in a neighborhood has one of those illuminated Ring signs in the front yard, is that enough to— JAMIE SIMINOFF: It’s a part of it. Is that just enough of a deterrent? The bad guys will know their face is going to be captured on video, and that will be analyzed by an AI, and something will happen. Do you have to do more outbound deterrents? I think that’s a part of it. Awareness is a big part of it. I think there are ways with lights also, using lighting to do stuff, that’s a big part of it. I think having just ... If, all of a sudden, someone comes outside because something’s an anomaly, that’s a big part of it. It doesn’t have to be some crazy thing. And that’s what I was saying, is a lot of these little things add up to make that work. So, when you think about it, okay, we can bring crime down in a neighborhood to close to zero in a neighborhood, what are the ratcheting steps? Does everyone just get the Ring camera, and your platform does all the work? Is it that someone gets caught and they tell all their friends in jail that they got caught? What are the steps? I think it’s really about bringing neighbors together for this particular thing. So, it’s about how you individually… and we’ve always thought about how each house is its own node controlled by the neighbors, so controlled by the person, and I’ll keep going back to that, which is one hundred percent, your video is in your control; everything you’re doing is in your control, whether you want to take part in anything is in your control. That has to be the first layer of all of it. But then, when something happens, do you want to take part in it? So, if you get an alert that this dog looks like the dog that’s in front of your house, can you contact your neighbor? You can decide not to take part in it, and then no one will ever know, and it’s fine, it’s just basically deleted, or you can take part in it. I think that’s how we can do things that can make a neighborhood into this node where individual neighbors are all on their own, but when things happen, they can work together as they want to. And you think that AI will accelerate the process? I think AI is a co-pilot. It is their assistant, and it’s helping them to figure this out. Because, again, if you’re just getting every motion alert, and if you have eight cameras and you’re just getting motion alerts all day, no human being can parse all this data. So that’s what I was talking to Jen about, is that I do think I see a way to use AI to help feed better data to us, which allows us to make better decisions and work together better. This is where we get to Flock, which Ring announced a partnership with in October 2025. Flock primarily makes cameras and systems to search video for the cops. You’ve probably seen Flock’s devices where you live — they’re those little solar-powered cameras and tracking devices affixed to streetlights or placed in the center of parking lots. They vacuum up large amounts of data, and the company claims it is anonymized before it’s made available to partners, which in most cases is local law enforcement. However, according to in-depth reporting from the excellent 404 Media, Flock’s data has often found its way to ICE, the FBI, the Secret Service, and other law enforcement agencies, without the requirement of a warrant. That’s because that data is willingly provided by local police. Last month, under intense scrutiny about what a deal with Flock would mean, Ring said that this partnership was not yet “live,” and that, “Ring has no partnership with ICE, does not give ICE videos, feeds, or back-end access, and does not share video with them.” For its part, Flock says the same — that it doesn’t actually work with ICE, but rather local law enforcement, and it’s those local agencies that work with ICE. This is the complication I mentioned earlier. If you’re a Decoder listener, you know where this is all going. I asked Jamie about all these databases, who owns them, and what it means to connect them all with AI: NILAY PATEL: But when you connect a bunch of those databases, particularly to facial recognition, there’s a turn in the privacy conversation where the stakes ratchet up really high, where maybe it’s gone forever. How are you thinking about that decision-making? Okay, we have a lot of intelligence in the AI; it’s trivial for the AI to connect to another store of information. That’s a thing you can do with AI, especially at a big company like Amazon, where you have lots of other stores of information. There’s a line, what’s the line for you? JAMIE SIMINOFF: There is a responsibility, obviously just to build safe products. So let’s just start with that. Yeah, we did announce facial, we call it Familiar Faces, but that’s not connected, that’s just for your... Your iPhone today. If you search your iPhone, it’s crazy. Search for someone’s name in your photos, and their pictures come up. So I do think there’s a balance between not allowing technology to exist that should exist that helps people and gives them more efficiency, gives them safer homes and then also, obviously, not creating this dystopian place. And so, I think that’s the responsibility, but what we’re doing with Familiar Faces is we’re just giving you the ability to say, when my wife comes home, don’t... Because it is silly. Why do I get an alert when my wife comes home? I don’t want it, I don’t need it. I’m asking this for a lot of reasons, but I look at what’s broadly happening with surveillance footage out in the world. And I’m not saying Ring is participating in this, I’m just giving you an example. ICE has facial recognition systems, and they are arguing that a positive match in their facial recognition system is a definitive determination of someone’s immigration status. That’s way out there. I don’t think you’re doing that. But you can get to, “Okay, we have facial recognition, we have a bunch of evidence coming off of Ring cameras, to make it really safe, you want to go from passive surveillance to active surveillance. That’s what the studies show. Now the camera will literally identify the criminal by face and tell the cops this person tried to steal a car from this driveway,” and that’s the thing that would get you to actually zero out crime. There’s a lot of risk in those steps. But if I draw the thread from what you’re saying, it’s all the way to the idea that the criminals won’t come here because the cameras will know who they are and tell the cops. Are you willing to go that far? I think it’s also that the cameras will alert people. Part of what made Ring and what made neighbors safer with Ring 1.0, and I think we are in Ring 2.0, is that there was no presence at the home. How did people break into homes? They would go and be knock-knock burglars. They would knock-knock, no one was home. It was 3PM, they’d go to the homes next door, find a place that was empty, and they’d go into the home.Ring allowed you to, now, all of a sudden, when someone comes up to the door, you’re like, “Oh, I got a motion alert. Hi, what’s going on?” and so it gave a presence to the home. So, I don’t think you have to go as far as that real time stuff to get to where we’re talking about, I think it’s more of the anomaly detection and allowing people to make it so that, if someone comes in, that you’re aware of what’s happening around the neighborhood because right now there’s no awareness of what’s going on around it. So I don’t think it’s as dystopian as where you’re going, and certainly it’s not what we’re building, and I do think we can impact things to a really high level in neighborhoods. Which, again, to the Jen Tuohy thing, in neighborhoods is what we were talking about, that with AI and what we’re doing with a bunch of Rings together. I think even the Dog Search Party is a good way to look at it, which is how these cameras come together for good in the neighborhood. Today, the backlash against surveillance has led Ring to kill that Flock deal. The company is also doing damage control about Search Party, telling The Verge that the technology that powers the feature is not “capable” of being used to find people, and that there’s no indication that such features are on future road maps. Sure, it seems obvious that Ring has a lot of trust to earn back here, and certainly, we are all thinking about what it means to put internet-connected security cameras in our homes. I think that’s good — and certainly overdue. But let me complicate this a little for you. At the same time this conversation about Ring is happening, we’re also watching regular people record the police and ICE with their cell phones, capturing critical documentary evidence of how those agencies are violating the rights of everyday Americans in ways that is leading to change, however slow. Minnesota governor Tim Walz is now telling people to hit record when they see ICE so the footage can be used in future prosecutions. And just last week, the FBI released video that Google appears to have specifically recovered from a Nest camera system at Nancy Guthrie’s house, in order to help identify her kidnapper. That’s a lot of video that’s being captured and used in ways that maybe don’t feel so invasive, and in some cases even feels good. But the systems that create, store, and share that video are all the same, and the guardrails around them are just as weak as whatever makes us feel uncomfortable about Ring. I’m not sure how to feel about all of that video, especially in a world where AI makes it easy to fake, and having some source of truth seems more important than ever. I asked Jamie about that, too — whether Ring will control all the video, or sign it with some metadata so people can ensure it’s real. NILAY PATEL: Presuming we have to have an authenticated server, there’s a crime in my neighborhood, and I’ve opted in, and we’re going to say the cops can only get the video from the Ring server, where we know it’s true. I might not be as in control of my video anymore. JAMIE SIMINOFF: No, not how it’s built and not while I’m here because the way it works is that you will decide if you want to or not want to share that video, which is your property, with someone. Now, once you share it, then it is up to us to figure out, to your point, how do we share it, how do we make sure that the digital fingerprint goes all the way through, or how does the chain of custody work of this video to make sure there’s no fake in the process of it? I think this is why it is important to build these systems. It’s going to be important, though. This is also where the government is going to have to step in. We’re going to have to deal with this across the board because we also have video coming off of cell phones. So, we do need to figure out how to build... And there’s going to be companies, Axon would probably be one of the companies. I don’t want to speak for them, but they have evidence.com, so to build these evidentiary systems to take in… Because Ring is one part of taking in data around, call it a crime scene, but cell phone video is maybe even more of a source today. So, how do you take that in? How do you make sure that it actually was captured on the iPhone directly and not tampered with between the two things? We’re going to have to figure it all out. I think we have to work together on it, and the AI stuff is pushing us to do it. I am proud that with Ring, we have built it so that you can take it directly and keep it on the server. You can understand where it was, where it’s from, where it was created, and we have that digital fingerprint on it and the audit trail of it. You’re going to have to do that more and more as this world is changing, you’re just not going to be able to trust that just because someone sends you a video doesn’t mean it’s true. You get the feeling we’ll be coming back to that idea quite a lot in the years to come. But today Ring has canceled its deal with Flock, and Flock itself is putting out blog posts flatly stating it does not have a contract with ICE, and noting that Ring’s other partner, Axon, does in fact have an ICE contract. In the meantime, Search Party is still active and on by default, although you can just go into settings and flip it off. And the enormous amount of video we all generate is being uploaded to servers run by big companies that have their own dealings with governments and law enforcement agencies far outside of our control. There are a lot of solutions to all these problems, and lots of ways to design regulations to balance out privacy and civil liberties with the needs of police. But right now, in 2026 America, I’m not sure were really going to be able to do that. So we’re going to keep pushing the leaders of these companies on what they really mean, and keep running the answers so you can listen and decide. I think it’s about time we started thinking about how all the technology we use to make our own lives better affects other people. Because that bigger conversation we need to have? Yeah, that’s what it’s really about. Questions or comments about this episode? Hit us up at decoder@theverge.com. We really do read every email! Decoder with Nilay Patel A podcast from The Verge about big ideas and other problems. Posts from this author will be added to your daily email digest and your homepage feed. See All by Nilay Patel Posts from this topic will be added to your daily email digest and your homepage feed. See All AI Posts from this topic will be added to your daily email digest and your homepage feed. See All Amazon Posts from this topic will be added to your daily email digest and your homepage feed. See All Decoder Posts from this topic will be added to your daily email digest and your homepage feed. See All Podcasts Posts from this topic will be added to your daily email digest and your homepage feed. See All Privacy Posts from this topic will be added to your daily email digest and your homepage feed. See All Tech Most Popular The Verge Daily A free daily digest of the news that matters most. This is the title for the native ad More in Podcasts This is the title for the native ad Top Stories © 2026 Vox Media, LLC. All Rights Reserved
========================================

[SOURCE: https://en.wikipedia.org/wiki/Extraterrestrial_life#cite_ref-60] \| [TOKENS: 11349]
Contents Extraterrestrial life Extraterrestrial life, or alien life (colloquially aliens), is life that originates from another world rather than on Earth. No extraterrestrial life has yet been scientifically or conclusively detected. Such life might range from simple forms such as prokaryotes to intelligent beings, possibly bringing forth civilizations that might be far more, or far less, advanced than humans. The Drake equation speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life is known as astrobiology. Speculation about inhabited worlds beyond Earth dates back to antiquity. Early Christian writers, including Augustine, discussed ideas from thinkers like Democritus and Epicurus about countless worlds in the vast universe. Pre-modern writers typically assumed extraterrestrial "worlds" were inhabited by living beings. William Vorilong, in the 15th century, acknowledged the possibility Jesus could have visited extraterrestrial worlds to redeem their inhabitants.: 26 In 1440, Nicholas of Cusa suggested Earth is a "brilliant star"; he theorized that all celestial bodies, even the Sun, could host life. Descartes wrote that there were no means to prove the stars were not inhabited by "intelligent creatures", but their existence was a matter of speculation.: 67 In comparison to the life-abundant Earth, the vast majority of intrasolar and extrasolar planets and moons have harsh surface conditions and disparate atmospheric chemistry, or lack an atmosphere. However, there are many extreme and chemically harsh ecosystems on Earth that do support forms of life and are often hypothesized to be the origin of life on Earth. Examples include life surrounding hydrothermal vents, acidic hot springs, and volcanic lakes, as well as halophiles and the deep biosphere. Since the mid-20th century, researchers have searched for extraterrestrial life and intelligence. Solar system studies focus on Venus, Mars, Europa, and Titan, while exoplanet discoveries now total 6,022 confirmed planets in 4,490 systems as of October 2025. Depending on the category of search, methods range from analysis of telescope and specimen data to radios used to detect and transmit interstellar communication. Interstellar travel remains largely hypothetical, with only the Voyager 1 and Voyager 2 probes confirmed to have entered the interstellar medium. The concept of extraterrestrial life, especially intelligent life, has greatly influenced culture and fiction. A key debate centers on contacting extraterrestrial intelligence: some advocate active attempts, while others warn it could be risky, given human history of exploiting other societies. Context Initially, after the Big Bang, the universe was too hot to allow life. It is estimated that the temperature of the universe was around 10 billion Kelvin at the one-second mark. Roughly 15 million years later, it cooled to temperate levels, though the elements of organic life were yet nonexistent. The only freely available elements at that point were hydrogen and helium. Carbon and oxygen (and later, water) would not appear until 50 million years later, created through stellar fusion. At that point, the difficulty for life to appear was not the temperature, but the scarcity of free heavy elements. Planetary systems emerged, and the first organic compounds may have formed in the protoplanetary disk of dust grains that would eventually create rocky planets like Earth. Although Earth was in a molten state after its birth and may have burned any organics that fell on it, it would have been more receptive once it cooled down. Once the right conditions on Earth were met, life started by a chemical process known as abiogenesis. Alternatively, life may have formed less frequently, then spread—by meteoroids, for example—between habitable planets in a process called panspermia. During most of its stellar evolution, stars combine hydrogen nuclei to make helium nuclei by stellar fusion, and the comparatively lighter weight of helium allows the star to release the extra energy. The process continues until the star uses all of its available fuel, with the speed of consumption being related to the size of the star. During its last stages, stars start combining helium nuclei to form carbon nuclei. The larger stars can further combine carbon nuclei to create oxygen and silicon, oxygen into neon and sulfur, and so on until iron. Ultimately, the star blows much of its content back into the stellar medium, where it would join clouds that would eventually become new generations of stars and planets. Many of those materials are the raw components of life on Earth. As this process takes place in all the universe, said materials are ubiquitous in the cosmos and not a rarity from the Solar System. Earth is a planet in the Solar System, a planetary system formed by a star at the center, the Sun, and the objects that orbit it: other planets, moons, asteroids, and comets. The sun is part of the Milky Way, a galaxy. The Milky Way is part of the Local Group, a galaxy group that is in turn part of the Laniakea Supercluster. The universe is composed of all similar structures in existence. The immense distances between celestial objects are a difficulty for studying extraterrestrial life. So far, humans have only set foot on the Moon and sent robotic probes to other planets and moons in the Solar System. Although probes can withstand conditions that may be lethal to humans, the distances cause time delays: the New Horizons took nine years after launch to reach Pluto. No probe has ever reached extrasolar planetary systems. The Voyager 2 left the Solar System at a speed of 50,000 kilometers per hour; if it headed towards the Alpha Centauri system, the closest one to Earth at 4.4 light years, it would reach it in 100,000 years. Under current technology, such systems can only be studied by telescopes, which have limitations. It is estimated that dark matter has a larger amount of combined matter than stars and gas clouds, but as it plays no role in the stellar evolution of stars and planets, it is usually not taken into account by astrobiology. There is an area around a star, the circumstellar habitable zone or "Goldilocks zone", wherein water may be at the right temperature to exist in liquid form at a planetary surface. This area is neither too close to the star, where water would become steam, nor too far away, where water would be frozen as ice. However, although useful as an approximation, planetary habitability is complex and defined by several factors. Being in the habitable zone is not enough for a planet to be habitable, not even to actually have such liquid water. Venus is located in the solar system's habitable zone, but does not have liquid water because of the conditions of its atmosphere. Jovian planets or gas giants are not considered habitable even if they orbit close enough to their stars as hot Jupiters, due to crushing atmospheric pressures. The actual distances for the habitable zones vary according to the type of star, and even the solar activity of each specific star influences the local habitability. The type of star also defines the time the habitable zone will exist, as its presence and limits will change along with the star's stellar evolution. The Big Bang occurred 13.8 billion years ago, the Solar System was formed 4.6 billion years ago, and the first hominids appeared 6 million years ago. Life on other planets may have started, evolved, given birth to extraterrestrial intelligences, and perhaps even faced a planetary extinction event millions or billions of years ago. When considered from a cosmic perspective, the brief times of existence of Earth's species may suggest that extraterrestrial life may be equally fleeting under such a scale. During a period of about 7 million years, from about 10 to 17 million years after the Big Bang, the background temperature was between 373 and 273 K (100 and 0 °C; 212 and 32 °F), allowing the possibility of liquid water if any planets existed. Avi Loeb (2014) speculated that primitive life might in principle have appeared during this window, which he called "the Habitable Epoch of the Early Universe". Life on Earth is quite ubiquitous across the planet and has adapted over time to almost all the available environments in it, extremophiles and the deep biosphere thrive at even the most hostile ones. As a result, it is inferred that life in other celestial bodies may be equally adaptive. However, the origin of life is unrelated to its ease of adaptation and may have stricter requirements. A celestial body may not have any life on it, even if it were habitable. Likelihood of existence Life in the cosmos beyond Earth has been observed. The hypothesis of ubiquitous extraterrestrial life relies on three main ideas. The first one, the size of the universe, allows for plenty of planets to have a similar habitability to Earth, and the age of the universe gives enough time for a long process analog to the history of Earth to happen there. The second is that the substances that make life, such as carbon and water, are ubiquitous in the universe. The third is that the physical laws are universal, which means that the forces that would facilitate or prevent the existence of life would be the same ones as on Earth. According to this argument, made by scientists such as Carl Sagan and Stephen Hawking, it would be improbable for life not to exist somewhere else other than Earth. This argument is embodied in the Copernican principle, which states that Earth does not occupy a unique position in the Universe, and the mediocrity principle, which states that there is nothing special about life on Earth. Other authors consider instead that life in the cosmos, or at least multicellular life, may actually be rare. The Rare Earth hypothesis maintains that life on Earth is possible because of a series of factors that range from the location in the galaxy and the configuration of the Solar System to local characteristics of the planet, and that it is unlikely that another planet simultaneously meets all such requirements. The proponents of this hypothesis consider that very little evidence suggests the existence of extraterrestrial life and that, at this point, it is just a desired result and not a reasonable scientific explanation for any gathered data. In 1961, astronomer and astrophysicist Frank Drake devised the Drake equation as a way to stimulate scientific dialogue at a meeting on the search for extraterrestrial intelligence (SETI). The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy. The Drake equation is:: xix where: and Drake's proposed estimates are as follows, but numbers on the right side of the equation are agreed as speculative and open to substitution: 10,000 = 5 ⋅ 0.5 ⋅ 2 ⋅ 1 ⋅ 0.2 ⋅ 1 ⋅ 10,000 {\displaystyle 10{,}000=5\cdot 0.5\cdot 2\cdot 1\cdot 0.2\cdot 1\cdot 10{,}000} [better source needed] The Drake equation has proved controversial since, although it is written as a math equation, none of its values were known at the time. Although some values may eventually be measured, others are based on social sciences and are not knowable by their very nature. This does not allow one to make noteworthy conclusions from the equation. Based on observations from the Hubble Space Telescope, there are nearly 2 trillion galaxies in the observable universe. It is estimated that at least ten percent of all Sun-like stars have a system of planets. In other words, there are 6.25×1018 stars with planets orbiting them in the observable universe. Even if it is assumed that only one out of a billion of these stars has planets supporting life, there would be some 6.25 billion life-supporting planetary systems in the observable universe. A 2013 study based on results from the Kepler spacecraft estimated that the Milky Way contains at least as many planets as it does stars, resulting in 100–400 billion exoplanets. The Nebular hypothesis that explains the formation of the Solar System and other planetary systems would suggest that those can have several configurations, and not all of them may have rocky planets within the habitable zone. The apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilisations and the lack of evidence for such civilisations is known as the Fermi paradox. Dennis W. Sciama claimed that life's existence in the universe depends on various fundamental constants. Zhi-Wei Wang and Samuel L. Braunstein suggest that a random universe capable of supporting life is likely to be just barely able to do so, giving a potential explanation to the Fermi paradox. Biochemical basis If extraterrestrial life exists, it could range from simple microorganisms and multicellular organisms similar to animals or plants, to complex alien intelligences akin to humans. When scientists talk about extraterrestrial life, they consider all those types. Although it is possible that extraterrestrial life may have other configurations, scientists use the hierarchy of lifeforms from Earth for simplicity, as it is the only one known to exist. The first basic requirement for life is an environment with non-equilibrium thermodynamics, which means that the thermodynamic equilibrium must be broken by a source of energy. The traditional sources of energy in the cosmos are the stars, such as for life on Earth, which depends on the energy of the sun. However, there are other alternative energy sources, such as volcanoes, plate tectonics, and hydrothermal vents. There are ecosystems on Earth in deep areas of the ocean that do not receive sunlight, and take energy from black smokers instead. Magnetic fields and radioactivity have also been proposed as sources of energy, although they would be less efficient ones. Life on Earth requires water in a liquid state as a solvent in which biochemical reactions take place. It is highly unlikely that an abiogenesis process can start within a gaseous or solid medium: the atom speeds, either too fast or too slow, make it difficult for specific ones to meet and start chemical reactions. A liquid medium also allows the transport of nutrients and substances required for metabolism. Sufficient quantities of carbon and other elements, along with water, might enable the formation of living organisms on terrestrial planets with a chemical make-up and temperature range similar to that of Earth. Life based on ammonia rather than water has been suggested as an alternative, though this solvent appears less suitable than water. It is also conceivable that there are forms of life whose solvent is a liquid hydrocarbon, such as methane, ethane or propane. Another unknown aspect of potential extraterrestrial life would be the chemical elements that would compose it. Life on Earth is largely composed of carbon, but there could be other hypothetical types of biochemistry. A replacement for carbon would need to be able to create complex molecules, store information required for evolution, and be freely available in the medium. To create DNA, RNA, or a close analog, such an element should be able to bind its atoms with many others, creating complex and stable molecules. It should be able to create at least three covalent bonds: two for making long strings and at least a third to add new links and allow for diverse information. Only nine elements meet this requirement: boron, nitrogen, phosphorus, arsenic, antimony (three bonds), carbon, silicon, germanium and tin (four bonds). As for abundance, carbon, nitrogen, and silicon are the most abundant ones in the universe, far more than the others. On Earth's crust the most abundant of those elements is silicon, in the Hydrosphere it is carbon and in the atmosphere, it is carbon and nitrogen. Silicon, however, has disadvantages over carbon. The molecules formed with silicon atoms are less stable, and more vulnerable to acids, oxygen, and light. An ecosystem of silicon-based lifeforms would require very low temperatures, high atmospheric pressure, an atmosphere devoid of oxygen, and a solvent other than water. The low temperatures required would add an extra problem, the difficulty to kickstart a process of abiogenesis to create life in the first place. Norman Horowitz, head of the Jet Propulsion Laboratory bioscience section for the Mariner and Viking missions from 1965 to 1976 considered that the great versatility of the carbon atom makes it the element most likely to provide solutions, even exotic solutions, to the problems of survival of life on other planets. However, he also considered that the conditions found on Mars were incompatible with carbon based life. Even if extraterrestrial life is based on carbon and uses water as a solvent, like Earth life, it may still have a radically different biochemistry. Life is generally considered to be a product of natural selection. It has been proposed that to undergo natural selection a living entity must have the capacity to replicate itself, the capacity to avoid damage/decay, and the capacity to acquire and process resources in support of the first two capacities. Life on Earth may have started with an RNA world and later evolved to its current form, where some of the RNA tasks were transferred to DNA and proteins. Extraterrestrial life may still be stuck using RNA, or evolve into other configurations. It is unclear if our biochemistry is the most efficient one that could be generated, or which elements would follow a similar pattern. However, it is likely that, even if cells had a different composition to those from Earth, they would still have a cell membrane. Life on Earth jumped from prokaryotes to eukaryotes and from unicellular organisms to multicellular organisms through evolution. So far no alternative process to achieve such a result has been conceived, even if hypothetical. Evolution requires life to be divided into individual organisms, and no alternative organisation has been satisfactorily proposed either. At the basic level, membranes define the limit of a cell, between it and its environment, while remaining partially open to exchange energy and resources with it. The evolution from simple cells to eukaryotes, and from them to multicellular lifeforms, is not guaranteed. The Cambrian explosion took place thousands of millions of years after the origin of life, and its causes are not fully known yet. On the other hand, the jump to multicellularity took place several times, which suggests that it could be a case of convergent evolution, and so likely to take place on other planets as well. Palaeontologist Simon Conway Morris considers that convergent evolution would lead to kingdoms similar to our plants and animals, and that many features are likely to develop in alien animals as well, such as bilateral symmetry, limbs, digestive systems and heads with sensory organs. Scientists from the University of Oxford analysed it from the perspective of evolutionary theory and wrote in a study in the International Journal of Astrobiology that aliens may be similar to humans. The planetary context would also have an influence: a planet with higher gravity would have smaller animals, and other types of stars can lead to non-green photosynthesizers. The amount of energy available would also affect biodiversity, as an ecosystem sustained by black smokers or hydrothermal vents would have less energy available than those sustained by a star's light and heat, and so its lifeforms would not grow beyond a certain complexity. There is also research in assessing the capacity of life for developing intelligence. It has been suggested that this capacity arises with the number of potential niches a planet contains, and that the complexity of life itself is reflected in the information density of planetary environments, which in turn can be computed from its niches. It is common knowledge that the conditions on other planets in the solar system, in addition to the many galaxies outside of the Milky Way galaxy, are very harsh and seem to be too extreme to harbor any life. The environmental conditions on these planets can have intense UV radiation paired with extreme temperatures, lack of water, and much more that can lead to conditions that don't seem to favor the creation or maintenance of extraterrestrial life. However, there has been much historical evidence that some of the earliest and most basic forms of life on Earth originated in some extreme environments that seem unlikely to have harbored life at least at one point in Earth's history. Fossil evidence as well as many historical theories backed up by years of research and studies have marked environments like hydrothermal vents or acidic hot springs as some of the first places that life could have originated on Earth. These environments can be considered extreme when compared to the typical ecosystems that the majority of life on Earth now inhabit, as hydrothermal vents are scorching hot due to the magma escaping from the Earth's mantle and meeting the much colder oceanic water. Even in today's world, there can be a diverse population of bacteria found inhabiting the area surrounding these hydrothermal vents which can suggest that some form of life can be supported even in the harshest of environments like the other planets in the solar system. The aspects of these harsh environments that make them ideal for the origin of life on Earth, as well as the possibility of creation of life on other planets, is the chemical reactions forming spontaneously. For example, the hydrothermal vents found on the ocean floor are known to support many chemosynthetic processes which allow organisms to utilize energy through reduced chemical compounds that fix carbon. In return, these reactions will allow for organisms to live in relatively low oxygenated environments while maintaining enough energy to support themselves. The early Earth environment was reducing and therefore, these carbon fixing compounds were necessary for the survival and possible origin of life on Earth. With the little amount of information that scientists have found regarding the atmosphere on other planets in the Milky Way galaxy and beyond, the atmospheres are most likely reducing or with very low oxygen levels, especially when compared with Earth's atmosphere. If there were the necessary elements and ions on these planets, the same carbon fixing, reduced chemical compounds occurring around hydrothermal vents could also occur on these planets' surfaces and possibly result in the origin of extraterrestrial life. Planetary habitability in the Solar System The Solar System has a wide variety of planets, dwarf planets, and moons, and each one is studied for its potential to host life. Each one has its own specific conditions that may benefit or harm life. So far, the only lifeforms found are those from Earth. No extraterrestrial intelligence other than humans exists or has ever existed within the Solar System. Astrobiologist Mary Voytek points out that it would be unlikely to find large ecosystems, as they would have already been detected by now. The inner Solar System is likely devoid of life. However, Venus is still of interest to astrobiologists, as it is a terrestrial planet that was likely similar to Earth in its early stages and developed in a different way. There is a greenhouse effect, the surface is the hottest in the Solar System, sulfuric acid clouds, all surface liquid water is lost, and it has a thick carbon-dioxide atmosphere with huge pressure. Comparing both helps to understand the precise differences that lead to beneficial or harmful conditions for life. And despite the conditions against life on Venus, there are suspicions that microbial life-forms may still survive in high-altitude clouds. Mars is a cold and almost airless desert, inhospitable to life. However, recent studies revealed that water on Mars used to be quite abundant, forming rivers, lakes, and perhaps even oceans. Mars may have been habitable back then, and life on Mars may have been possible. But when the planetary core ceased to generate a magnetic field, solar winds removed the atmosphere and the planet became vulnerable to solar radiation. Ancient life-forms may still have left fossilised remains, and microbes may still survive deep underground. As mentioned, the gas giants and ice giants are unlikely to contain life. The most distant solar system bodies, found in the Kuiper Belt and outwards, are locked in permanent deep-freeze, but cannot be ruled out completely. Although the giant planets themselves are highly unlikely to have life, there is much hope to find it on moons orbiting these planets. Europa, from the Jovian system, has a subsurface ocean below a thick layer of ice. Ganymede and Callisto also have subsurface oceans, but life is less likely in them because water is sandwiched between layers of solid ice. Europa would have contact between the ocean and the rocky surface, which helps the chemical reactions. It may be difficult to dig so deep in order to study those oceans, though. Enceladus, a tiny moon of Saturn with another subsurface ocean, may not need to be dug, as it releases water to space in eruption columns. The space probe Cassini flew inside one of these, but could not make a full study because NASA did not expect this phenomenon and did not equip the probe to study ocean water. Still, Cassini detected complex organic molecules, salts, evidence of hydrothermal activity, hydrogen, and methane. Titan is the only celestial body in the Solar System besides Earth that has liquid bodies on the surface. It has rivers, lakes, and rain of hydrocarbons, methane, and ethane, and even a cycle similar to Earth's water cycle. This special context encourages speculations about lifeforms with different biochemistry, but the cold temperatures would make such chemistry take place at a very slow pace. Water is rock-solid on the surface, but Titan does have a subsurface water ocean like several other moons. However, it is of such a great depth that it would be very difficult to access it for study. Scientific search The science that searches and studies life in the universe, both on Earth and elsewhere, is called astrobiology. With the study of Earth's life, the only known form of life, astrobiology seeks to study how life starts and evolves and the requirements for its continuous existence. This helps to determine what to look for when searching for life in other celestial bodies. This is a complex area of study, and uses the combined perspectives of several scientific disciplines, such as astronomy, biology, chemistry, geology, oceanography, and atmospheric sciences. The scientific search for extraterrestrial life is being carried out both directly and indirectly. As of September 2017[update], 3,667 exoplanets in 2,747 systems have been identified, and other planets and moons in the Solar System hold the potential for hosting primitive life such as microorganisms. As of 8 February 2021, an updated status of studies considering the possible detection of lifeforms on Venus (via phosphine) and Mars (via methane) was reported. Scientists search for biosignatures within the Solar System by studying planetary surfaces and examining meteorites. Some claim to have identified evidence that microbial life has existed on Mars. In 1996, a controversial report stated that structures resembling nanobacteria were discovered in a meteorite, ALH84001, formed of rock ejected from Mars. Although all the unusual properties of the meteorite were eventually explained as the result of inorganic processes, the controversy over its discovery laid the groundwork for the development of astrobiology. An experiment on the two Viking Mars landers reported gas emissions from heated Martian soil samples that some scientists argue are consistent with the presence of living microorganisms. Lack of corroborating evidence from other experiments on the same samples suggests that a non-biological reaction is a more likely hypothesis. In February 2005 NASA scientists reported they may have found some evidence of extraterrestrial life on Mars. The two scientists, Carol Stoker and Larry Lemke of NASA's Ames Research Center, based their claim on methane signatures found in Mars's atmosphere resembling the methane production of some forms of primitive life on Earth, as well as on their own study of primitive life near the Rio Tinto river in Spain. NASA officials soon distanced NASA from the scientists' claims, and Stoker herself backed off from her initial assertions. In November 2011, NASA launched the Mars Science Laboratory that landed the Curiosity rover on Mars. It is designed to assess the past and present habitability on Mars using a variety of scientific instruments. The rover landed on Mars at Gale Crater in August 2012. A group of scientists at Cornell University started a catalog of microorganisms, with the way each one reacts to sunlight. The goal is to help with the search for similar organisms in exoplanets, as the starlight reflected by planets rich in such organisms would have a specific spectrum, unlike that of starlight reflected from lifeless planets. If Earth was studied from afar with this system, it would reveal a shade of green, as a result of the abundance of plants with photosynthesis. In August 2011, NASA studied meteorites found on Antarctica, finding adenine, guanine, hypoxanthine, and xanthine. Adenine and guanine are components of DNA, and the others are used in other biological processes. The studies ruled out pollution of the meteorites on Earth, as those components would not be freely available the way they were found in the samples. This discovery suggests that several organic molecules that serve as building blocks of life may be generated within asteroids and comets. In October 2011, scientists reported that cosmic dust contains complex organic compounds ("amorphous organic solids with a mixed aromatic-aliphatic structure") that could be created naturally, and rapidly, by stars. It is still unclear if those compounds played a role in the creation of life on Earth, but Sun Kwok, of the University of Hong Kong, thinks so. "If this is the case, life on Earth may have had an easier time getting started as these organics can serve as basic ingredients for life." In August 2012, and in a world first, astronomers at Copenhagen University reported the detection of a specific sugar molecule, glycolaldehyde, in a distant star system. The molecule was found around the protostellar binary IRAS 16293-2422, which is located 400 light years from Earth. Glycolaldehyde is needed to form ribonucleic acid, or RNA, which is similar in function to DNA. This finding suggests that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation. In December 2023, astronomers reported the first time discovery, in the plumes of Enceladus, moon of the planet Saturn, of hydrogen cyanide, a possible chemical essential for life as we know it, as well as other organic molecules, some of which are yet to be better identified and understood. According to the researchers, "these [newly discovered] compounds could potentially support extant microbial communities or drive complex organic synthesis leading to the origin of life." Although most searches are focused on the biology of extraterrestrial life, an extraterrestrial intelligence capable enough to develop a civilization may be detectable by other means as well. Technology may generate technosignatures, effects on the native planet that may not be caused by natural causes. There are three main types of techno-signatures considered: interstellar communications, effects on the atmosphere, and planetary-sized structures such as Dyson spheres. Organizations such as the SETI Institute search the cosmos for potential forms of communication. They started with radio waves, and now search for laser pulses as well. The challenge for this search is that there are natural sources of such signals as well, such as gamma-ray bursts and supernovae, and the difference between a natural signal and an artificial one would be in its specific patterns. Astronomers intend to use artificial intelligence for this, as it can manage large amounts of data and is devoid of biases and preconceptions. Besides, even if there is an advanced extraterrestrial civilization, there is no guarantee that it is transmitting radio communications in the direction of Earth. The length of time required for a signal to travel across space means that a potential answer may arrive decades or centuries after the initial message. The atmosphere of Earth is rich in nitrogen dioxide as a result of air pollution, which can be detectable. The natural abundance of carbon, which is also relatively reactive, makes it likely to be a basic component of the development of a potential extraterrestrial technological civilization, as it is on Earth. Fossil fuels may likely be generated and used on such worlds as well. The abundance of chlorofluorocarbons in the atmosphere can also be a clear technosignature, considering their role in ozone depletion. Light pollution may be another technosignature, as multiple lights on the night side of a rocky planet can be a sign of advanced technological development. However, modern telescopes are not strong enough to study exoplanets with the required level of detail to perceive it. The Kardashev scale proposes that a civilization may eventually start consuming energy directly from its local star. This would require giant structures built next to it, called Dyson spheres. Those speculative structures would cause an excess infrared radiation, that telescopes may notice. The infrared radiation is typical of young stars, surrounded by dusty protoplanetary disks that will eventually form planets. An older star such as the Sun would have no natural reason to have excess infrared radiation. The presence of heavy elements in a star's light-spectrum is another potential biosignature; such elements would (in theory) be found if the star were being used as an incinerator/repository for nuclear waste products. Some astronomers search for extrasolar planets that may be conducive to life, narrowing the search to terrestrial planets within the habitable zones of their stars. Since 1992, over four thousand exoplanets have been discovered (6,128 planets in 4,584 planetary systems including 1,017 multiple planetary systems as of 30 October 2025). The extrasolar planets so far discovered range in size from that of terrestrial planets similar to Earth's size to that of gas giants larger than Jupiter. The number of observed exoplanets is expected to increase greatly in the coming years.[better source needed] The Kepler space telescope has also detected a few thousand candidate planets, of which about 11% may be false positives. There is at least one planet on average per star. About 1 in 5 Sun-like stars[a] have an "Earth-sized"[b] planet in the habitable zone,[c] with the nearest expected to be within 12 light-years distance from Earth. Assuming 200 billion stars in the Milky Way,[d] that would be 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if red dwarfs are included. The rogue planets in the Milky Way possibly number in the trillions. The nearest known exoplanet is Proxima Centauri b, located 4.2 light-years (1.3 pc) from Earth in the southern constellation of Centaurus. As of March 2014[update], the least massive exoplanet known is PSR B1257+12 A, which is about twice the mass of the Moon. The most massive planet listed on the NASA Exoplanet Archive is DENIS-P J082303.1−491201 b, about 29 times the mass of Jupiter, although according to most definitions of a planet, it is too massive to be a planet and may be a brown dwarf instead. Almost all of the planets detected so far are within the Milky Way, but there have also been a few possible detections of extragalactic planets. The study of planetary habitability also considers a wide range of other factors in determining the suitability of a planet for hosting life. One sign that a planet probably already contains life is the presence of an atmosphere with significant amounts of oxygen, since that gas is highly reactive and generally would not last long without constant replenishment. This replenishment occurs on Earth through photosynthetic organisms. One way to analyse the atmosphere of an exoplanet is through spectrography when it transits its star, though this might only be feasible with dim stars like white dwarfs. History and cultural impact The modern concept of extraterrestrial life is based on assumptions that were not commonplace during the early days of astronomy. The first explanations for the celestial objects seen in the night sky were based on mythology. Scholars from Ancient Greece were the first to consider that the universe is inherently understandable and rejected explanations based on supernatural incomprehensible forces, such as the myth of the Sun being pulled across the sky in the chariot of Apollo. They had not developed the scientific method yet and based their ideas on pure thought and speculation, but they developed precursor ideas to it, such as that explanations had to be discarded if they contradict observable facts. The discussions of those Greek scholars established many of the pillars that would eventually lead to the idea of extraterrestrial life, such as Earth being round and not flat. The cosmos was first structured in a geocentric model that considered that the sun and all other celestial bodies revolve around Earth. However, they did not consider them as worlds. In Greek understanding, the world was composed by both Earth and the celestial objects with noticeable movements. Anaximander thought that the cosmos was made from apeiron, a substance that created the world, and that the world would eventually return to the cosmos. Eventually two groups emerged, the atomists that thought that matter at both Earth and the cosmos was equally made of small atoms of the classical elements (earth, water, fire and air), and the Aristotelians who thought that those elements were exclusive of Earth and that the cosmos was made of a fifth one, the aether. Atomist Epicurus thought that the processes that created the world, its animals and plants should have created other worlds elsewhere, along with their own animals and plants. Aristotle thought instead that all the earth element naturally fell towards the center of the universe, and that would make it impossible for other planets to exist elsewhere. Under that reasoning, Earth was not only in the center, it was also the only planet in the universe. Cosmic pluralism, the plurality of worlds, or simply pluralism, describes the philosophical belief in numerous "worlds" in addition to Earth, which might harbor extraterrestrial life. The earliest recorded assertion of extraterrestrial human life is found in ancient scriptures of Jainism. There are multiple "worlds" mentioned in Jain scriptures that support human life. These include, among others, Bharat Kshetra, Mahavideh Kshetra, Airavat Kshetra, and Hari kshetra. Medieval Muslim writers like Fakhr al-Din al-Razi and Muhammad al-Baqir supported cosmic pluralism on the basis of the Qur'an. Chaucer's poem The House of Fame engaged in medieval thought experiments that postulated the plurality of worlds. However, those ideas about other worlds were different from the current knowledge about the structure of the universe, and did not postulate the existence of planetary systems other than the Solar System. When those authors talk about other worlds, they talk about places located at the center of their own systems, and with their own stellar vaults and cosmos surrounding them. The Greek ideas and the disputes between atomists and Aristotelians outlived the fall of the Greek empire. The Great Library of Alexandria compiled information about it, part of which was translated by Islamic scholars and thus survived the end of the Library. Baghdad combined the knowledge of the Greeks, the Indians, the Chinese and its own scholars, and the knowledge expanded through the Byzantine Empire. From there it eventually returned to Europe by the time of the Middle Ages. However, as the Greek atomist doctrine held that the world was created by random movements of atoms, with no need for a creator deity, it became associated with atheism, and the dispute intertwined with religious ones. Still, the Church did not react to those topics in a homogeneous way, and there were stricter and more permissive views within the church itself. The first known mention of the term 'panspermia' was in the writings of the 5th-century BC Greek philosopher Anaxagoras. He proposed the idea that life exists everywhere. By the time of the late Middle Ages there were many known inaccuracies in the geocentric model, but it was kept in use because naked eye observations provided limited data. Nicolaus Copernicus started the Copernican Revolution by proposing that the planets revolve around the sun rather than Earth. His proposal had little acceptance at first because, as he kept the assumption that orbits were perfect circles, his model led to as many inaccuracies as the geocentric one. Tycho Brahe improved the available data with naked-eye observatories, which worked with highly complex sextants and quadrants. Tycho could not make sense of his observations, but Johannes Kepler did: orbits were not perfect circles, but ellipses. This knowledge benefited the Copernican model, which worked now almost perfectly. The invention of the telescope a short time later, perfected by Galileo Galilei, clarified the final doubts, and the paradigm shift was completed. Under this new understanding, the notion of extraterrestrial life became feasible: if Earth is but just a planet orbiting around a star, there may be planets similar to Earth elsewhere. The astronomical study of distant bodies also proved that physical laws are the same elsewhere in the universe as on Earth, with nothing making the planet truly special. The new ideas were met with resistance from the Catholic church. Galileo was tried for the heliocentric model, which was considered heretical, and forced to recant it. The best-known early-modern proponent of ideas of extraterrestrial life was the Italian philosopher Giordano Bruno, who argued in the 16th century for an infinite universe in which every star is surrounded by its own planetary system. Bruno wrote that other worlds "have no less virtue nor a nature different to that of our earth" and, like Earth, "contain animals and inhabitants". Bruno's belief in the plurality of worlds was one of the charges leveled against him by the Venetian Holy Inquisition, which tried and executed him. The heliocentric model was further strengthened by the postulation of the theory of gravity by Sir Isaac Newton. This theory provided the mathematics that explains the motions of all things in the universe, including planetary orbits. By this point, the geocentric model was definitely discarded. By this time, the use of the scientific method had become a standard, and new discoveries were expected to provide evidence and rigorous mathematical explanations. Science also took a deeper interest in the mechanics of natural phenomena, trying to explain not just the way nature works but also the reasons for working that way. There was very little actual discussion about extraterrestrial life before this point, as the Aristotelian ideas remained influential while geocentrism was still accepted. When it was finally proved wrong, it not only meant that Earth was not the center of the universe, but also that the lights seen in the sky were not just lights, but physical objects. The notion that life may exist in them as well soon became an ongoing topic of discussion, although one with no practical ways to investigate. The possibility of extraterrestrials remained a widespread speculation as scientific discovery accelerated. William Herschel, the discoverer of Uranus, was one of many 18th–19th-century astronomers who believed that the Solar System is populated by alien life. Other scholars of the period who championed "cosmic pluralism" included Immanuel Kant and Benjamin Franklin. At the height of the Enlightenment, even the Sun and Moon were considered candidates for extraterrestrial inhabitants. Speculation about life on Mars increased in the late 19th century, following telescopic observation of apparent Martian canals – which soon, however, turned out to be optical illusions. Despite this, in 1895, American astronomer Percival Lowell published his book Mars, followed by Mars and its Canals in 1906, proposing that the canals were the work of a long-gone civilisation. Spectroscopic analysis of Mars's atmosphere began in earnest in 1894, when U.S. astronomer William Wallace Campbell showed that neither water nor oxygen was present in the Martian atmosphere. By 1909 better telescopes and the best perihelic opposition of Mars since 1877 conclusively put an end to the canal hypothesis. As a consequence of the belief in the spontaneous generation there was little thought about the conditions of each celestial body: it was simply assumed that life would thrive anywhere. This theory was disproved by Louis Pasteur in the 19th century. Popular belief in thriving alien civilisations elsewhere in the solar system still remained strong until Mariner 4 and Mariner 9 provided close images of Mars, which debunked forever the idea of the existence of Martians and decreased the previous expectations of finding alien life in general. The end of the spontaneous generation belief forced investigation into the origin of life. Although abiogenesis is the more accepted theory, a number of authors reclaimed the term "panspermia" and proposed that life was brought to Earth from elsewhere. Some of those authors are Jöns Jacob Berzelius (1834), Kelvin (1871), Hermann von Helmholtz (1879) and, somewhat later, by Svante Arrhenius (1903). The science fiction genre, although not so named during the time, developed during the late 19th century. The expansion of the genre of extraterrestrials in fiction influenced the popular perception over the real-life topic, making people eager to jump to conclusions about the discovery of aliens. Science marched at a slower pace, some discoveries fueled expectations and others dashed excessive hopes. For example, with the advent of telescopes, most structures seen on the Moon or Mars were immediately attributed to Selenites or Martians, and later ones (such as more powerful telescopes) revealed that all such discoveries were natural features. A famous case is the Cydonia region of Mars, first imaged by the Viking 1 orbiter. The low-resolution photos showed a rock formation that resembled a human face, but later spacecraft took photos in higher detail that showed that there was nothing special about the site. The search and study of extraterrestrial life became a science of its own, astrobiology. Also known as exobiology, this discipline is studied by the NASA, the ESA, the INAF, and others. Astrobiology studies life from Earth as well, but with a cosmic perspective. For example, abiogenesis is of interest to astrobiology, not because of the origin of life on Earth, but for the chances of a similar process taking place in other celestial bodies. Many aspects of life, from its definition to its chemistry, are analyzed as either likely to be similar in all forms of life across the cosmos or only native to Earth. Astrobiology, however, remains constrained by the current lack of extraterrestrial life-forms to study, as all life on Earth comes from the same ancestor, and it is hard to infer general characteristics from a group with a single example to analyse. The 20th century came with great technological advances, speculations about future hypothetical technologies, and an increased basic knowledge of science by the general population thanks to science divulgation through the mass media. The public interest in extraterrestrial life and the lack of discoveries by mainstream science led to the emergence of pseudosciences that provided affirmative, if questionable, answers to the existence of aliens. Ufology claims that many unidentified flying objects (UFOs) would be spaceships from alien species, and ancient astronauts hypothesis claim that aliens would have visited Earth in antiquity and prehistoric times but people would have failed to understand it by then. Most UFOs or UFO sightings can be readily explained as sightings of Earth-based aircraft (including top-secret aircraft), known astronomical objects or weather phenomenons, or as hoaxes. Looking beyond the pseudosciences, Lewis White Beck strove to elevate the level of public discourse on the topic of extraterrestrial life by tracing the evolution of philosophical thought over the centuries from ancient times into the modern era. His review of the contributions made by Lucretius, Plutarch, Aristotle, Copernicus, Immanuel Kant, John Wilkins, Charles Darwin and Karl Marx demonstrated that even in modern times, humanity could be profoundly influenced in its search for extraterrestrial life by subtle and comforting archetypal ideas which are largely derived from firmly held religious, philosophical and existential belief systems. On a positive note, however, Beck further argued that even if the search for extraterrestrial life proves to be unsuccessful, the endeavor itself could have beneficial consequences by assisting humanity in its attempt to actualize superior ways of living here on Earth. By the 21st century, it was accepted that multicellular life in the Solar System can only exist on Earth, but the interest in extraterrestrial life increased regardless. This is a result of the advances in several sciences. The knowledge of planetary habitability allows to consider on scientific terms the likelihood of finding life at each specific celestial body, as it is known which features are beneficial and harmful for life. Astronomy and telescopes also improved to the point exoplanets can be confirmed and even studied, increasing the number of search places. Life may still exist elsewhere in the Solar System in unicellular form, but the advances in spacecraft allow to send robots to study samples in situ, with tools of growing complexity and reliability. Although no extraterrestrial life has been found and life may still be just a rarity from Earth, there are scientific reasons to suspect that it can exist elsewhere, and technological advances that may detect it if it does. Many scientists are optimistic about the chances of finding alien life. In the words of SETI's Frank Drake, "All we know for sure is that the sky is not littered with powerful microwave transmitters". Drake noted that it is entirely possible that advanced technology results in communication being carried out in some way other than conventional radio transmission. At the same time, the data returned by space probes, and giant strides in detection methods, have allowed science to begin delineating habitability criteria on other worlds, and to confirm that at least other planets are plentiful, though aliens remain a question mark. The Wow! signal, detected in 1977 by a SETI project, remains a subject of speculative debate. On the other hand, other scientists are pessimistic. Jacques Monod wrote that "Man knows at last that he is alone in the indifferent immensity of the universe, whence which he has emerged by chance". In 2000, geologist and paleontologist Peter Ward and astrobiologist Donald Brownlee published a book entitled Rare Earth: Why Complex Life is Uncommon in the Universe.[better source needed] In it, they discussed the Rare Earth hypothesis, in which they claim that Earth-like life is rare in the universe, whereas microbial life is common. Ward and Brownlee are open to the idea of evolution on other planets that is not based on essential Earth-like characteristics such as DNA and carbon. As for the possible risks, theoretical physicist Stephen Hawking warned in 2010 that humans should not try to contact alien life forms. He warned that aliens might pillage Earth for resources. "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans", he said. Jared Diamond had earlier expressed similar concerns. On 20 July 2015, Hawking and Russian billionaire Yuri Milner, along with the SETI Institute, announced a well-funded effort, called the Breakthrough Initiatives, to expand efforts to search for extraterrestrial life. The group contracted the services of the 100-meter Robert C. Byrd Green Bank Telescope in West Virginia in the United States and the 64-meter Parkes Telescope in New South Wales, Australia. On 13 February 2015, scientists (including Geoffrey Marcy, Seth Shostak, Frank Drake and David Brin) at a convention of the American Association for the Advancement of Science, discussed Active SETI and whether transmitting a message to possible intelligent extraterrestrials in the Cosmos was a good idea; one result was a statement, signed by many, that a "worldwide scientific, political and humanitarian discussion must occur before any message is sent". Government responses The 1967 Outer Space Treaty and the 1979 Moon Agreement define rules of planetary protection against potentially hazardous extraterrestrial life. COSPAR also provides guidelines for planetary protection. A committee of the United Nations Office for Outer Space Affairs had in 1977 discussed for a year strategies for interacting with extraterrestrial life or intelligence. The discussion ended without any conclusions. As of 2010, the UN lacks response mechanisms for the case of an extraterrestrial contact. One of the NASA divisions is the Office of Safety and Mission Assurance (OSMA), also known as the Planetary Protection Office. A part of its mission is to "rigorously preclude backward contamination of Earth by extraterrestrial life." In 2016, the Chinese Government released a white paper detailing its space program. According to the document, one of the research objectives of the program is the search for extraterrestrial life. It is also one of the objectives of the Chinese Five-hundred-meter Aperture Spherical Telescope (FAST) program. In 2020, Dmitry Rogozin, the head of the Russian space agency, said the search for extraterrestrial life is one of the main goals of deep space research. He also acknowledged the possibility of existence of primitive life on other planets of the Solar System. The French space agency has an office for the study of "non-identified aero spatial phenomena". The agency is maintaining a publicly accessible database of such phenomena, with over 1600 detailed entries. According to the head of the office, the vast majority of entries have a mundane explanation; but for 25% of entries, their extraterrestrial origin can neither be confirmed nor denied. In 2020, chairman of the Israel Space Agency Isaac Ben-Israel stated that the probability of detecting life in outer space is "quite large". But he disagrees with his former colleague Haim Eshed who stated that there are contacts between an advanced alien civilisation and some of Earth's governments. In fiction Although the idea of extraterrestrial peoples became feasible once astronomy developed enough to understand the nature of planets, they were not thought of as being any different from humans. Having no scientific explanation for the origin of mankind and its relation to other species, there was no reason to expect them to be any other way. This was changed by the 1859 book On the Origin of Species by Charles Darwin, which proposed the theory of evolution. Now with the notion that evolution on other planets may take other directions, science fiction authors created bizarre aliens, clearly distinct from humans. A usual way to do that was to add body features from other animals, such as insects or octopuses. Costuming and special effects feasibility alongside budget considerations forced films and TV series to tone down the fantasy, but these limitations lessened since the 1990s with the advent of computer-generated imagery (CGI), and later on as CGI became more effective and less expensive. Real-life events sometimes captivate people's imagination and this influences the works of fiction. For example, during the Barney and Betty Hill incident, the first recorded claim of an alien abduction, the couple reported that they were abducted and experimented on by aliens with oversized heads, big eyes, pale grey skin, and small noses, a description that eventually became the grey alien archetype once used in works of fiction. See also Notes References Further reading External links
========================================

[SOURCE: https://www.wired.com/subscribe/] \| [TOKENS: 222]
Insights at the intersection oftechnology, power, and culture Get access to exclusive benefits including5 all-new premium newsletters. What's Included in Annual Digital Give the Gift of WIRED today. Sign in to manage your account online.Questions? Visit our FAQ. The regular annual rate is $80. WIRED publishes at least 4 issues per year. First issue mails within 8-10 weeks. Plus tax where applicable. All prices are in U.S. dollars. Introductory offers are only available to customers who have not been subscribed to WIRED within the last 18 months. All orders subject to approval. Where applicable, limit one free gift per address; ships within 6-8 weeks. Import fees, declaration fees, import duties and/or taxes may be imposed on free gifts shipped outside the U.S. All such fees are the customer's sole responsibility. By ordering, you agree not to resell any subscriptions purchased from this site. Subscribers: If your subscription becomes undeliverable, we have no further obligation unless we receive a corrected address and/or email within one year.
========================================

[SOURCE: https://en.wikipedia.org/wiki/PlayStation_(console)#cite_ref-gaydarcontrollers_179-0] \| [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
========================================

[SOURCE: https://www.ynet.co.il/economy/article/hjvoisn0011l] \| [TOKENS: 314]
רק "חברות נכות" מנפיקות בבורסה בת"א? תשובת ענקית הסייבר לשר הכלכלה ניר ברקת התפנה מהסל של המדינה כדי להביע אי אמון בכלכלה הישראלית, מלחמת הדורות בשווייץ, ממדאני ממשיך לחפש איך לפגוע בישראלים בתפוח הגדול - והכסף הגדול שמבריח מיליארדרים מקליפורניה. וגם: האם ענף הבנייה יצטרף למאה ה-21? \| הצמרת הכלכלית – הכתבות הנצפות של השבוע
========================================

[SOURCE: https://en.wikipedia.org/wiki/Black_hole#cite_note-296] \| [TOKENS: 13839]
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
========================================

[SOURCE: https://en.wikipedia.org/wiki/Fox_Weather] \| [TOKENS: 991]
Contents Fox Weather Fox Weather is an American digital broadcast television network and streaming channel operated by Fox Corporation which launched on October 25, 2021, to provide weather forecasts and information for the United States. The service is available through free ad-supported streaming television services as well select digital subchannels of Fox Television Stations, YouTube TV, Hulu + Live TV, their own YouTube channel, Fox One, The Roku Channel, FuboTV, DirecTV Stream, Xfinity, Cox, Xumo, Amazon Fire TV, Sling Freestream, Dish Network, Samsung TV Plus, Pluto TV, its website and mobile apps, the mobile and digital media player apps of Fox, Fox News and Fox Business, the websites of Fox's owned and operated stations, the OTT service Tubi, and simulcasted on weekend mornings from 6 to 9 AM ET on Fox Business and in daytime and various weekend slots on select MyNetworkTV stations. During significant weather events, Fox Weather is often simulcast on Fox News, LiveNOW from Fox or Fox Business. History On December 9, 2020, Fox News Media announced the forthcoming launch of an ad-supported weather service that would include local and national weather related news. On June 24, 2021, Fox News Media announced a slate of six meteorologists who would make up the team reporting for the channel, joining from other local TV stations. The channel is overseen by Fox News Media CEO Suzanne Scott and executive Sharri Berg. News of the launch sparked discussion on how the channel will cover climate change, an issue their sister channel Fox News has often dismissed. Regarding how the issue of climate change will be addressed on the new network, Berg stated in an interview that “...climate change is part of our lives. It’s how we live. It’s not going to be ignored.” On August 18, 2021, Berg announced that Fox Weather would add three correspondents and five multimedia journalists to the team. On September 1, 2021, Fox Weather released their first promo and announced that they would be launching in October. The launch date was later announced for October 25. On October 18, 2021, Berg announced that Fox Weather would add four additional meteorologists and a multimedia journalist to the team. The network was also added as an over-the-air digital subchannel at the start of 2022 in markets served by the network's owned-and-operated stations group, presumably with local insertion allowing local forecasts and severe weather coverage. A weekend morning simulcast of the channel airs on Fox Business from 6 to 8 a.m. ET, which started on December 4. YouTube TV added Fox Weather on February 2, 2022, becoming the first weather-focused channel to air on the OTT service. On February 8, Berg announced that Fox Weather had also been added to the Amazon News and The Roku Channel OTT services, and would be added to Xumo and FuboTV later in February. Berg also announced that, in addition to its addition to over-the-air digital subchannels, Fox Weather content would be simulcast for 1–2 hours daily on Fox Television Stations' MyNetworkTV and independent stations. On March 14, 2022, Berg announced that Fox Weather had hired Bryan Norcross as its hurricane specialist. On April 12, 2022, Fox Weather announced that it has unveiled a Ford F-250 truck called the "Fox Weather Beast." On May 2, 2022, Fox Weather debuted an hourly update podcast/report "Fox Weather Update." Weather updates and rolling coverage are also a part of the hourly loop of streaming/Sirius XM station Fox News Headlines 24/7. On December 7, 2022, Fox News Audio and TuneIn, the live-streaming service announced their long partnership which includes Fox Weather for audio streaming. On July 6, 2023, Berg announced that Fox Weather had hired Bob Van Dillen as on-air host. He started his role on July 10, 2023. On August 23, 2023, Fox Weather was added to Samsung TV Plus and Cox. On November 29, 2023, Fox Weather was added to Sling Freestream and Dish Network. In August 2024, Fox Weather added long-time The Weather Channel personality Mike Seidel as a meteorologist and storm specialist. He started covering Hurricane Debby. On August 1, 2024, Fox Weather was added to Pluto TV. In February 2025, Fox Weather launched a premium ad-free subscription plan. Location and team The channel's headquarters is at Fox News Media's office and draws on their existing meteorologists across US stations as well as dedicated meteorologists for the channel. Programming Currently, Fox Weather's schedule consists of the following programs: Affiliates See also References
========================================

[SOURCE: https://www.mako.co.il/food-feed/2026-m02_w03/shorts-63d9b8405da6c91027.htm] \| [TOKENS: 101]
We are sorry... ...but your activity and behavior on this website made us think that you are a bot. Please solve this CAPTCHA in helping us understand your behavior to grant access You reached this page when trying to access https://www.mako.co.il/food-feed/2026-m02_w03/shorts-63d9b8405da6c91027.htm from 79.181.162.231 on February 21 2026, 10:56:43 UTC
========================================

[SOURCE: https://en.wikipedia.org/wiki/Nehardea_Academy] \| [TOKENS: 744]
Contents Nehardea Academy Nehardea Academy (Hebrew: ישיבת נהרדעא), previously also known as The House of Learning (Jewish Babylonian Aramaic: בי מדרשא, romanized: Bē Miḏraš) or The Boundary (Jewish Babylonian Aramaic: תחומא, romanized: Tḥūmā) was one of the major Talmudic academies in Babylonia (Mesopotamia), active intermittently from the early Amoraic period until the end of the Geonic period. It was established by the amora Samuel of Nehardea, one of the great sages of Babylon. History Samuel founded the academy at Nehardea, which in time attracted thousands of students. Along with Sura Academy founded by Abba Arikha, it opened a new era in which Babylon became the center of Judaism. After Rav's death, many students from Sura moved to Nehardea. Despite the fact that Rav Kahana III's Pum-Nahara Academy was subordinated to Sura Academy, from the time Rav died the heads of the Nehardea Academy came to visit Rav Kahana in Pum-Nahara with the intention of strengthening the ties between the two academies. This reinforcement of ties is attested by the fact that Kahana III gave his funeral oration to Rav Zevid of Nehardea at Pum-Nahara, a funeral oration, most probably in conjunction with the fact that Rav Kahana III was a disciple of Rav Zevid of Nehardea. R. Nahman of Nehardea visited Rav Kahana III in Pum-Nahara on the eve of Yom Kippur; it is possible he came in order to participate with them in the prayers of the holy day. The academy had a special custom to show respect for the sages of The Land of Israel: When a guest came from the Land of Israel, he taught in the presence of the dean and all students. After the class ended, a long and lively debate was conducted in which the students would inundate the guest with academic questions. Among the scholars who attended the Nehardea Academy, there were known Amoraim sages cited in the Talmud, such as R. Shimi of Nehardea, R. Dimi of Nehardea, Rav Zevid of Nehardea, and Amemar. In many Talmud citations, there is a mention of Nehardea's academy methods, however Amemar states that despite the fact that he is a Nehardean, he thinks otherwise. It is unclear whether he meant that Nehardea's academy thinks otherwise and not as what is known to be the methods, or was he an independent in his thinking. After the death of Samuel, the academy split. The academy itself, headed by Rav Huna, a disciple of Samuel, moved to Sura, while another student of Rav and Shmuel, Judah ben Ezekiel, founded the Pumbedita Academy. However, Judah ben Ezekiel and his followers regarded Rav Huna as Gedol haDor, until upon his death in 297 (Hebrew calendar: ד"א נ"ח or ד'נ"ח ). In some cases, where there is disagreement among scholars, the Nehardea academy practiced Rabbah bar Rav Huna'S view, and it may have to do with the fact that his son was the head of the academy and one of its leaders. See also References
========================================

[SOURCE: https://www.wired.com/newsletter?sourceCode=HeaderAndFooter] \| [TOKENS: 121]
Get the best of WIRED in your inbox Preview and select the newsletters you’d like to receive. Then, add your email to sign up. Preview and select the newsletters you’d like to receive. Then, add your email to sign up. © 2026 Condé Nast. All rights reserved. WIRED may earn a portion of sales from products that are purchased through our site as part of our Affiliate Partnerships with retailers. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Condé Nast. Ad Choices
========================================

[SOURCE: https://www.theverge.com/podcast/878797/ring-super-bowl-ad-backlash-epstein-files-chatgpt-vergecast] \| [TOKENS: 2035]
PodcastsClosePodcastsPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PodcastsAICloseAIPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All AIPolicyClosePolicyPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PolicyRing’s adorable surveillance hellscapeAlso on The Vergecast: the Epstein files, ChatGPT ads, and Ferrari EVs.Also on The Vergecast: the Epstein files, ChatGPT ads, and Ferrari EVs.by David PierceCloseDavid PierceEditor-at-LargePosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by David PierceFeb 13, 2026, 4:10 PM UTCLinkShareGiftDavid PierceCloseDavid PiercePosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by David Pierce is editor-at-large and Vergecast co-host with over a decade of experience covering consumer tech. Previously, at Protocol, The Wall Street Journal, and Wired.You can watch Ring’s recent Super Bowl ad and see a cute story about dogs being reunited with their families. You can also watch the very same ad and see the seeds being planted for a massively connected, utterly ubiquitous surveillance system that will end the concept of privacy forever. Maybe you can even see both at the same time.Verge subscribers, don’t forget you get exclusive access to ad-free Vergecast wherever you get your podcasts. Head here. Not a subscriber? You can sign up here.On this episode of The Vergecast, Nilay and David talk about the Super Bowl ad that worried so many people, why Ring would build a feature like this in the first place, and whether all this surveillance is a feature or a bug. Given that the Ring controversy happened the same week as Google recovered important (and supposedly deleted) footage from Nancy Guthrie’s Nest camera, it seems worth debating what we really want from our security cameras, and what “security” even means in this context.After that, the hosts turn to yet another week of chaos in the AI industry. A number of important people at companies like Anthropic and OpenAI are quitting their jobs, and issuing dire warnings about the power and peril of AI on the way out. What are we to make of the end of OpenAI’s Mission Alignment team, or the Anthropic safety leader who wrote that “the world is in peril?” There are even tech employees worried about what the advent of chatbot advertising will do to your data, your conversations with AI, and the world. We try to put all the pieces together, and figure out what’s really worth being worried about going forward.Finally, in the lightning round, it’s time for an extra long installment of Brendan Carr is a Dummy (theme music by Michiel Vanhoudt), the latest Siri delays, the forthcoming Ferrari EV, and more. If you want to know more about everything we discuss in this episode, here are some links to get you started:Jeffrey Epstein’s digital cleanup crewJeffrey Epstein might not have created /pol/, but he helped carry out its missionAmazon Ring’s lost dog ad sparks backlash amid fears of mass surveillanceWhat the Guthrie case reveals about your ‘deleted’ doorbell footageOpenAI’s supposedly ‘leaked’ Super Bowl ad with ear buds and a shiny orb was a hoaxOpenAI reportedly disbanded its Mission Alignment team.ChatGPT’s cheapest options now show you ads Here are the brands bringing ads to ChatGPTFrom The New York Times: I Left My Job at OpenAI. Putting Ads on ChatGPT Was the Last Straw.From The New Yorker: What Is Claude? Anthropic Doesn’t Know, EitherFrom The New York Post: Apple News promotes left-leaning media outlets -- as it shuts out conservative sites entirely: studyFTC says it’s ‘not the speech police’ in letter warning Apple News about its alleged promotion of left-leaning outletsApple keeps hitting bumps with its overhauled SiriFerrari’s first EV will have an interior designed by Jony Ive YouTube is coming to the Apple Vision ProParamount ups its offer for Warner Bros. Discovery, again.Follow topics and authors from this story to see more like this in your personalized homepage feed and to receive email updates.David PierceCloseDavid PierceEditor-at-LargePosts from this author will be added to your daily email digest and your homepage feed.FollowFollowSee All by David PierceAICloseAIPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All AIOpenAICloseOpenAIPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All OpenAIPodcastsClosePodcastsPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PodcastsPolicyClosePolicyPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All PolicySmart HomeCloseSmart HomePosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All Smart HomeTechCloseTechPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All TechVergecastCloseVergecastPosts from this topic will be added to your daily email digest and your homepage feed.FollowFollowSee All VergecastMost PopularMost PopularXbox chief Phil Spencer is leaving MicrosoftRead Microsoft gaming CEO Asha Sharma’s first memo on the future of XboxThe RAM shortage is coming for everything you care aboutAmazon blames human employees for an AI coding agent’s mistakeWill Stancil, man of the people or just an annoying guy?The Verge DailyA free daily digest of the news that matters most.Email (required)Sign UpBy submitting your email, you agree to our Terms and Privacy Notice. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.Advertiser Content FromThis is the title for the native ad Posts from this topic will be added to your daily email digest and your homepage feed. See All Podcasts Posts from this topic will be added to your daily email digest and your homepage feed. See All AI Posts from this topic will be added to your daily email digest and your homepage feed. See All Policy Ring’s adorable surveillance hellscape Also on The Vergecast: the Epstein files, ChatGPT ads, and Ferrari EVs. Also on The Vergecast: the Epstein files, ChatGPT ads, and Ferrari EVs. Posts from this author will be added to your daily email digest and your homepage feed. See All by David Pierce Posts from this author will be added to your daily email digest and your homepage feed. See All by David Pierce You can watch Ring’s recent Super Bowl ad and see a cute story about dogs being reunited with their families. You can also watch the very same ad and see the seeds being planted for a massively connected, utterly ubiquitous surveillance system that will end the concept of privacy forever. Maybe you can even see both at the same time. Verge subscribers, don’t forget you get exclusive access to ad-free Vergecast wherever you get your podcasts. Head here. Not a subscriber? You can sign up here. On this episode of The Vergecast, Nilay and David talk about the Super Bowl ad that worried so many people, why Ring would build a feature like this in the first place, and whether all this surveillance is a feature or a bug. Given that the Ring controversy happened the same week as Google recovered important (and supposedly deleted) footage from Nancy Guthrie’s Nest camera, it seems worth debating what we really want from our security cameras, and what “security” even means in this context. After that, the hosts turn to yet another week of chaos in the AI industry. A number of important people at companies like Anthropic and OpenAI are quitting their jobs, and issuing dire warnings about the power and peril of AI on the way out. What are we to make of the end of OpenAI’s Mission Alignment team, or the Anthropic safety leader who wrote that “the world is in peril?” There are even tech employees worried about what the advent of chatbot advertising will do to your data, your conversations with AI, and the world. We try to put all the pieces together, and figure out what’s really worth being worried about going forward. Finally, in the lightning round, it’s time for an extra long installment of Brendan Carr is a Dummy (theme music by Michiel Vanhoudt), the latest Siri delays, the forthcoming Ferrari EV, and more. If you want to know more about everything we discuss in this episode, here are some links to get you started: Posts from this author will be added to your daily email digest and your homepage feed. See All by David Pierce Posts from this topic will be added to your daily email digest and your homepage feed. See All AI Posts from this topic will be added to your daily email digest and your homepage feed. See All OpenAI Posts from this topic will be added to your daily email digest and your homepage feed. See All Podcasts Posts from this topic will be added to your daily email digest and your homepage feed. See All Policy Posts from this topic will be added to your daily email digest and your homepage feed. See All Smart Home Posts from this topic will be added to your daily email digest and your homepage feed. See All Tech Posts from this topic will be added to your daily email digest and your homepage feed. See All Vergecast Most Popular The Verge Daily A free daily digest of the news that matters most. This is the title for the native ad More in Podcasts This is the title for the native ad Top Stories © 2026 Vox Media, LLC. All Rights Reserved
========================================

Subsets and Splits

No community queries yet

The top public SQL queries from the community will appear here once available.