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[SOURCE: https://en.wikipedia.org/wiki/File:PIA26046-Mars-BuriedIceMaps-20231026.jpg] | [TOKENS: 826] |
File:PIA26046-Mars-BuriedIceMaps-20231026.jpg Summary https://photojournal.jpl.nasa.gov/catalog/PIA26046 These Mars global maps show the likely distribution of water ice buried within the upper 3 feet (1 meter) of the planet's surface and represent the latest data from the Subsurface Water Ice Mapping project, or SWIM. SWIM uses data acquired by science instruments aboard three NASA orbital missions to estimate where ice may be hiding below the surface. Superimposed on the globes are the locations of ice-exposing meteoroid impacts, which provide an independent means to test the mapping results. The ice-exposing impacts were spotted by the High-Resolution Imaging Science Experiment (HiRISE), a camera aboard NASA's Mars Reconnaissance Orbiter. While other instruments at Mars can only suggest where buried water ice is located, HiRISE's imagery of ice-exposing impacts can confirm where ice is present. Most of these craters are no more than 33 feet (10 meters) in diameter, although in 2022 HiRISE captured a 492-foot-wide (150-meter-wide) impact crater that revealed a motherlode of ice that had been hiding beneath the surface. This crater is indicated with a circle in the upper-left portion of the right-most globe above. Scientists can use mapping data like this to decide where the first astronauts on Mars should land: Buried ice will be a vital resource for the first people to set foot on Mars, serving as drinking water and a key ingredient for rocket fuel. It would also be a major scientific target: Astronauts or robots could one day drill ice cores much as scientists do on Earth, uncovering the climate history of Mars and exploring potential habitats (past or present) for microbial life. The need to look for subsurface ice arises because liquid water isn't stable on the Martian surface: The atmosphere is so thin that water immediately vaporizes. There's plenty of ice at the Martian poles – mostly made of water, although carbon dioxide, or dry ice, can be found as well – but those regions are too cold for astronauts (or robots) to survive for long. Licensing Afrikaans ∙ العربية ∙ беларуская (тарашкевіца) ∙ български ∙ Bahaso Jambi ∙ català ∙ čeština ∙ dansk ∙ Deutsch ∙ English ∙ español ∙ فارسی ∙ français ∙ galego ∙ magyar ∙ հայերեն ∙ Bahasa Indonesia ∙ italiano ∙ 日本語 ∙ 한국어 ∙ македонски ∙ മലയാളം ∙ Nederlands ∙ polski ∙ português ∙ русский ∙ sicilianu ∙ slovenščina ∙ Türkçe ∙ українська ∙ 简体中文 ∙ 繁體中文 ∙ +/− Attribution Caltech's disclaimer: Caltech makes no representations or warranties with respect to ownership of copyrights in the images, and does not represent others who may claim to be authors or owners of copyright of any of the images, and makes no warranties as to the quality of the images. Caltech shall not be responsible for any loss or expenses resulting from the use of the images, and you release and hold Caltech harmless from all liability arising from such use. Usage on the English Wikipedia: On the English Wikipedia you can use the {{JPL Image}} template to display the copyright notice. (See w:Wikipedia:Using JPL images for details) File history Click on a date/time to view the file as it appeared at that time. File usage The following 2 pages use this file: Global file usage The following other wikis use this file: |
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[SOURCE: https://en.wikipedia.org/wiki/Software_release_life_cycle#Alpha] | [TOKENS: 2518] |
Contents Software release life cycle Page version status This is an accepted version of this page The software release life cycle is the process of developing, testing, and distributing a software product (e.g., an operating system). It typically consists of several stages, such as pre-alpha, alpha, beta, and release candidate, before the final version, or "gold", is released to the public. Pre-alpha refers to the early stages of development, when the software is still being designed and built. Alpha testing is the first phase of formal testing, during which the software is tested internally using white-box techniques. Beta testing is the next phase, in which the software is tested by a larger group of users, typically outside the organization that developed it. The beta phase is focused on reducing impacts on users and may include usability testing. After beta testing, the software may go through one or more release candidate phases, in which it is refined and tested further, before the final version is released. Some software, particularly in the internet and technology industries, is released in a perpetual beta state, meaning that it is continuously being updated and improved, and is never considered to be a fully completed product. This approach allows for a more agile development process and enables the software to be released and used by users earlier in the development cycle. Stages of development Pre-alpha refers to all activities performed during the software project before formal testing. These activities can include requirements analysis, software design, software development, and unit testing. In typical open source development, there are several types of pre-alpha versions. Milestone versions include specific sets of functions and are released as soon as the feature is complete.[citation needed] The alpha phase of the release life cycle is the first phase of software testing (alpha is the first letter of the Greek alphabet, used as the number 1). In this phase, developers generally test the software using white-box techniques. Additional validation is then performed using black-box or gray-box techniques, by another testing team. Moving to black-box testing inside the organization is known as alpha release. Alpha software is not thoroughly tested by the developer before it is released to customers. Alpha software may contain serious errors, and any resulting instability could cause crashes or data loss. Alpha software may not contain all of the features that are planned for the final version. In general, external availability of alpha software is uncommon for proprietary software, while open source software often has publicly available alpha versions. The alpha phase usually ends with a feature freeze, indicating that no more features will be added to the software. At this time, the software is said to be feature-complete. A beta test is carried out following acceptance testing at the supplier's site (the alpha test) and immediately before the general release of the software as a product. A feature-complete (FC) version of a piece of software has all of its planned or primary features implemented but is not yet final due to bugs, performance or stability issues. This occurs at the end of alpha testing in development. Usually, feature-complete software still has to undergo beta testing and bug fixing, as well as performance or stability enhancement before it can go to release candidate, and finally gold status. Beta, named after the second letter of the Greek alphabet, is the software development phase following alpha. A beta phase generally begins when the software is feature-complete but likely to contain several known or unknown bugs. Software in the beta phase will generally have many more bugs in it than completed software and speed or performance issues, and may still cause crashes or data loss. The focus of beta testing is reducing impacts on users, often incorporating usability testing. The process of delivering a beta version to the users is called beta release and is typically the first time that the software is available outside of the organization that developed it. Software beta releases can be either open or closed, depending on whether they are openly available or only available to a limited audience. Beta version software is often useful for demonstrations and previews within an organization and to prospective customers. Some developers refer to this stage as a preview, preview release, prototype, technical preview or technology preview (TP). Beta testers are people who actively report issues with beta software. They are usually customers or representatives of prospective customers of the organization that develops the software. Beta testers tend to volunteer their services free of charge but often receive versions of the product they test, discounts on the release version, or other incentives. Some software is kept in so-called perpetual beta, where new features are continually added to the software without establishing a final "stable" release. As the Internet has facilitated the rapid and inexpensive distribution of software, companies have begun to take a looser approach to the use of the word beta. A release candidate (RC), also known as gamma testing or "going silver", is a beta version with the potential to be a stable product, which is ready to release unless significant bugs emerge. In this stage of product stabilization, all product features have been designed, coded, and tested through one or more beta cycles with no known showstopper-class bugs. A release is called code complete when the development team agrees that no entirely new source code will be added to this release. There could still be source code changes to fix defects, changes to documentation and data files, and peripheral code for test cases or utilities.[citation needed] Also called production release, the stable release is the last release candidate (RC) which has passed all stages of verification and tests. Any known remaining bugs are considered acceptable. This release goes to production. Some software products (e.g. Linux distributions like Debian) also have long-term support (LTS) releases which are based on full releases that have already been tried and tested and receive only security updates.[citation needed] Release Once released, the software is generally known as a "stable release". The formal term often depends on the method of release: physical media, online release, or a web application. Usually the released software is assigned an official version name or version number. (Pre-release software may or may not have a separate internal project code name or internal version number). The term "release to manufacturing" (RTM), also known as "going gold", is a term used when a software product is ready to be delivered. This build may be digitally signed, allowing the end user to verify the integrity and authenticity of the software purchase. The RTM build is known as the "gold master" or GM is sent for mass duplication or disc replication if applicable. The terminology is taken from the audio record-making industry, specifically the process of mastering. RTM precedes general availability (GA) when the product is released to the public. A golden master build (GM) is typically the final build of a piece of software in the beta stages for developers. Typically, for iOS, it is the final build before a major release, however, there have been a few exceptions. RTM is typically used in certain retail mass-production software contexts—as opposed to a specialized software production or project in a commercial or government production and distribution—where the software is sold as part of a bundle in a related computer hardware sale and typically where the software and related hardware is ultimately to be available and sold on mass/public basis at retail stores to indicate that the software has met a defined quality level and is ready for mass retail distribution. RTM could also mean in other contexts that the software has been delivered or released to a client or customer for installation or distribution to the related hardware end user computers or machines. The term does not define the delivery mechanism or volume; it only states that the quality is sufficient for mass distribution. The deliverable from the engineering organization is frequently in the form of a golden master media used for duplication or to produce the image for the web. General availability (GA) is the marketing stage at which all necessary commercialization activities have been completed and a software product is available for purchase, depending, however, on language, region, and electronic vs. media availability. Commercialization activities could include security and compliance tests, as well as localization and worldwide availability. The time between RTM and GA can take from days to months before a generally available release can be declared, due to the time needed to complete all commercialization activities required by GA. At this stage, the software has "gone live". Release to the Web (RTW) or Web release is a means of software delivery that utilizes the Internet for distribution. No physical media are produced in this type of release mechanism by the manufacturer. Web releases have become more common as Internet usage has grown.[citation needed] Support During its supported lifetime, the software is sometimes subjected to service releases, patches or service packs, sometimes also called "interim releases" or "maintenance releases" (MR). For example, Microsoft released three major service packs for the 32-bit editions of Windows XP and two service packs for the 64-bit editions. Such service releases contain a collection of updates, fixes, and enhancements, delivered in the form of a single installable package. They may also implement new features. Some software is released with the expectation of regular support. Classes of software that generally involve protracted support as the norm include anti-virus suites and massively multiplayer online games. Continuing with this Windows XP example, Microsoft did offer paid updates for five more years after the end of extended support. This means that support ended on April 8, 2019. When software is no longer sold or supported, the product is said to have reached end-of-life, to be discontinued, retired, deprecated, abandoned, or obsolete, but user loyalty may continue its existence for some time, even long after its platform is obsolete—e.g., the Common Desktop Environment and Sinclair ZX Spectrum. After the end-of-life date, the developer will usually not implement any new features, fix existing defects, bugs, or vulnerabilities (whether known before that date or not), or provide any support for the product. If the developer wishes, they may release the source code, so that the platform may be maintained by volunteers. History Usage of the "alpha/beta" test terminology originated at IBM.[citation needed] Similar terminologies for IBM's software development were used by people involved with IBM from at least the 1950s (and probably earlier). "A" test was the verification of a new product before the public announcement. The "B" test was the verification before releasing the product to be manufactured. The "C" test was the final test before the general availability of the product. As software became a significant part of IBM's offerings, the alpha test terminology was used to denote the pre-announcement test and the beta test was used to show product readiness for general availability. Martin Belsky, a manager on some of IBM's earlier software projects claimed to have invented the terminology. IBM dropped the alpha/beta terminology during the 1960s, but by then it had received fairly wide notice. The usage of "beta test" to refer to testing done by customers was not done in IBM. Rather, IBM used the term "field test". Major public betas developed afterward, with early customers having purchased a "pioneer edition" of the WordVision word processor for the IBM PC for $49.95. In 1984, Stephen Manes wrote that "in a brilliant marketing coup, Bruce and James Program Publishers managed to get people to pay for the privilege of testing the product." In September 2000, a boxed version of Apple's Mac OS X Public Beta operating system was released. Between September 2005 and May 2006, Microsoft released community technology previews (CTPs) for Windows Vista. From 2009 to 2011, Minecraft was in public beta. In February 2005, ZDNet published an article about the phenomenon of a beta version often staying for years and being used as if it were at the production level. It noted that Gmail and Google News, for example, had been in beta for a long time although widely used; Google News left beta in January 2006, followed by Google Apps (now named Google Workspace), including Gmail, in July 2009. Since the introduction of Windows 8, Microsoft has called pre-release software a preview rather than beta. All pre-release builds released through the Windows Insider Program launched in 2014 are termed "Insider Preview builds". "Beta" may also indicate something more like a release candidate, or as a form of time-limited demo, or marketing technique. See also References |
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[SOURCE: https://en.wikipedia.org/wiki/Light_gun] | [TOKENS: 789] |
Contents Light gun A light gun is a pointing device for computers and a control device for arcade and video games, typically shaped to resemble a pistol. Early history The first light guns were produced in the 1930s, following the development of light-sensing vacuum tubes. In 1936, the technology was introduced in arcade shooting games, beginning with the Seeburg Ray-O-Lite. These games evolved throughout subsequent decades, culminating in Sega's Periscope, released in 1966 as the company's first successful game, which requires the player to target cardboard ships. Periscope is an early electro-mechanical game, and the first arcade game to cost one quarter per play. Sega's 1969 game Missile features electronic sound and a moving film strip to represent the targets on a projection screen, and its 1972 game Killer Shark features a mounted light gun with targets whose movement and reactions are displayed using back image projection onto a screen. Nintendo released the Beam Gun in 1970 and the Laser Clay Shooting System in 1973, followed in 1974 by the arcade game Wild Gunman, which uses film projection to display the target on the screen. In 1975, Sega released the early co-operative light gun shooters Balloon Gun and Bullet Mark. The first detection method, used by the NES Zapper, involves drawing each target sequentially in white light after the screen blacks out. The computer knows that if the diode detects light as it is drawing a square (or after the screen refreshes), then that is the target at which the gun is pointed. Essentially, the diode tells the computer whether or not the player hit something, and for n objects, the sequence of the drawing of the targets tell the computer which target the player hit after 1 + ceil(log2(n)) refreshes (one refresh to determine if any target at all was hit and ceil(log2(n)) to do a binary search for the object that was hit). A side effect of this is that in some games, a player can point the gun at a light bulb or other bright light source, pull the trigger, and cause the system to falsely detect a hit on the first target every time. Some games account for this either by detecting if all targets appear to match or by displaying a black screen and verifying that no targets match. The Wii Remote uses an infrared video camera in the handheld controller, rather than a simple sensor. Wesley Yin-Poole stated that the Wii Remote was not as accurate as a traditional light gun. GunCon 3 is an infrared light gun used for the PlayStation 3 port of Time Crisis 4. Rectangular positioning is similar to image capture, except it disregards any on-screen details and only determines the rectangular outline of the game screen. By determining the size and distortion of the rectangle outline of the screen, it is possible to calculate where exactly the light gun is pointing. This method was introduced by the Sinden Lightgun. Positional gun The positional gun is common in video arcades, as a non-optical alternative to a light gun. The positional gun is permanently mounted on a swivel on the cabinet, as an analog joystick for aiming crosshairs onscreen. This is typically more expensive initially but easier to maintain and repair. Positional gun games include Silent Scope, the arcade version of Resident Evil Survivor 2, Space Gun, Revolution X, and Terminator 2: Judgment Day. Console conversions may use light guns. A positional gun is essentially an analog joystick that records the position of the gun to determine the player's aim on the screen. The gun must be calibrated, which usually happens after powering up. Early examples of a positional gun include Sega's Sea Devil in 1972, Taito's Attack in 1976, and Cross Fire in 1977, and Nintendo's Battle Shark in 1978. Models See also References |
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[SOURCE: https://en.wikipedia.org/wiki/TADS] | [TOKENS: 527] |
Contents Text Adventure Development System Text Adventure Development System (TADS) is a prototype-based domain-specific programming language and set of standard libraries for creating interactive fiction (IF) games. History The original TADS 1 was released by High Energy Software as shareware in 1988, and was followed by TADS 2 not long after. From the late 1980s to early 1990s, free development tools such as TADS and Inform enabled amateur communities to create interactive fiction. In the mid-1990s, TADS was a top development tool for interactive fiction. At the time, it was a more improved tool for parsing and world building than existing systems like AGT (Adventure Game Toolkit). TADS 2 syntax is based on C, with bits of Pascal. TADS 2 has been maintained and updated at regular intervals by its creator, Michael J. Roberts, even after it became freeware in July 1996. Graham Nelson, creator of Inform, describes Inform and TADS as the "only two systems... widely used" in the last half of the 1990s, and TADS has been called "The second most commonly used IF programming language today". Multimedia TADS, introduced in 1998, allows games to display graphics, animation and play sounds, if the platform supports it. In 2006, TADS received a major overhaul with the release of TADS 3, which is a complete rewrite of the TADS engine, only retaining the platform-dependent code to ease porting. TADS 3 uses a language with a syntax that resembles C++ and Java. It has many new features, such as efficient dynamic objects (with automatic garbage collection), structured exceptions, native UTF-8 strings, and many useful function classes. TADS 3 has been ported to MS-DOS, Mac, and Unix. TADS games Games written in TADS are compiled to a platform-independent format that can be played on any computer for which a suitable virtual machine (VM) exists. Such virtual machines exist for several platforms, and in this respect, TADS closely follows the example of the original Infocom Z-machine, as well as modern languages such as Java and C#. Whereas the TADS 1 and 2 VMs had to parse the commands entered by the player, before sending the results on to the game, TADS 3 employs a more general-purpose virtual machine, where the command-parsing is done by the game code itself, akin to Inform. The rationale for this is that it is easier to customize the parser. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Spriggan] | [TOKENS: 938] |
Contents Spriggan A spriggan /sprɪdʒən/ is a legendary creature from Cornish folklore. Spriggans are particularly associated with West Penwith in Cornwall. Etymology Spriggan is pronounced /sprɪdʒən/ rather than /sprɪɡən/; the word is borrowed from the Cornish plural spyrysyon 'spirits'. In folklore Spriggans have often been depicted as grotesquely ugly, wizened old men with large childlike heads. They were said to be found at old ruins, cairns, and barrows guarding buried treasure. Although small in stature, they have often been considered to be the ghosts of giants and retained gigantic strength, and in one story collected by Robert Hunt, they showed the ability to swell to enormous size. Hunt associated these spirits with the hillfort known as Trencrom Hill in Cornwall. Spriggans were notorious for their unpleasant dispositions, and delighted in working mischief against those who offended them. They raised sudden whirlwinds to terrify travellers, sent storms to blight crops, and sometimes stole away mortal children, leaving their ugly changelings in their place. They were blamed if a house was robbed or a building collapsed, or if cattle were stolen. In one story, an old woman got the better of a band of spriggans by turning her clothing inside-out (turning clothing supposedly being as effective as holy water or iron in repelling fairies) to gain their loot. On Christmas Eve, spriggans met for a midnight Mass at the bottom of deep mines, and passersby could hear them singing. However, it was not spriggans but the buccas or knockers who were associated with tin mining, and who played a protective role towards the miners. Based on the collections of Robert Hunt and William Bottrell, Katharine Briggs characterized the spriggans as fairy bodyguards. The English Dialect Dictionary (1905) compared them to the trolls of Scandinavia. Sculpture A sculpture of a spriggan by Marilyn Collins can be seen in Crouch End, London, in some arches lining a section of the Parkland Walk (a disused railway line). The sculpture was installed in 1993. If walking along the Parkland Walk from Finsbury Park to Highgate station, the Spriggan is to the right just before the disused railway platforms of the former Crouch End station. To the left, on the southside of the Parkland Walk is Crouch Hill Park where Ashmount School has been located since January 2013. The sculpture is sometimes mistaken for the Green Man or Pan.[citation needed] In popular culture Spriggans have been featured as fey creatures in the Dungeons & Dragons roleplaying game since the 1980s. Additionally, in the roleplaying game Changeling: The Dreaming by White Wolf Publishing, Spriggans are a type of dark fae called Thallain. Here they are characterized as lazy, crude and cruel thieves who enjoy guarding treasures. They have an inherent weakness that causes them to kidnap young children as they enjoy both the parent's and child's misery, although they never directly harm the child. They are a dark counterpart to the Piskies. Spriggans—in the style of the Parkland Walk sculpture—can be found in The Elder Scrolls series of video games, where they are portrayed as exclusively female. In the video game World of Warcraft, the Spriggan are a race of fae loyal to the Drust, a dark and twisted version of the fae. In the Japanese roleplaying video game Trails Through Daybreak, Spriggan is a title taken on by the game's main protagonist, Van Arkride. The title represents a person who solves morally gray problems—an underground fixer. In the video game Last Epoch, Spriggan Form is a Druid-only Shapeshift Spell Skill, which transforms players' characters into a forest Deity, increasing their casting capabilities and granting new abilities. Spriggan Form revolves around Attunement and Vitality attributes and scales on those. In the anime and toy franchise Beyblade Burst, the character Shu Kuranai uses a Beyblade named Spriggan (localized as "Spryzen" in English-language releases). Across the series, multiple upgraded versions of Spriggan/Spryzen appear, each incorporating themes of duality, balance, and transformation—traits that connect loosely to the mythical spriggan's reputed changeable or deceptive nature. See also Citations General sources |
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[SOURCE: https://en.wikipedia.org/wiki/Frances_Haugen] | [TOKENS: 3086] |
Contents Frances Haugen Frances Haugen (born 1983 or 1984) is an American product manager, data engineer, scientist, and whistleblower. She disclosed tens of thousands of Facebook's internal documents to the Securities and Exchange Commission and The Wall Street Journal in 2021. Haugen has also testified before the United States Senate Commerce Committee's Sub-Committee on Consumer Protection, Product Safety, and Data Security, the Parliament of the United Kingdom, and the European Parliament. In 2023, her memoir, The Power of One: How I Found the Strength to Tell the Truth and Why I Blew the Whistle on Facebook, was published by Little, Brown & Company. Early life and education Haugen was raised in Iowa City, Iowa, where she attended Horn Elementary and Northwest Junior High School, and graduated from Iowa City West High School in 2002. Her father was a doctor, and her mother became an Episcopalian priest after an academic career. Haugen studied electrical and computer engineering in the founding class at the Franklin W. Olin College of Engineering and graduated in 2006. She later earned a Master of Business Administration from Harvard Business School in 2011. Career In 2006, after graduating from college, Haugen was hired by Google, and worked on Google Ads, Google Book Search, on a class action litigation settlement related to Google's publication of copyrighted book content, as well as on Google+. At Google, Haugen co-authored a patent for a method of adjusting the ranking of search results. During her career at Google, she completed her MBA; her tuition was paid by Google. While at Google, she was a technical co-founder of the desktop dating app Secret Agent Cupid, precursor to the mobile app Hinge. In 2015, she began work as a data product manager at Yelp to improve search using image recognition, and after a year, moved to Pinterest. In 2019, Haugen joined Facebook, after a person close to her became radicalized online; she "felt compelled to take an active role in creating a better, less toxic Facebook" and thought "Facebook has the potential to bring out the best of us". When Facebook recruited her, she expressed interest in a role related to misinformation; in 2019 she became a product manager on the Facebook civic integrity team. Following the 2020 United States elections, Facebook dissolved its civic integrity team, and Haugen became disillusioned. While still at Facebook, she decided to become a whistleblower, due to what she has since described as a pattern of Facebook's prioritization of profit over public safety, and left Facebook in May 2021. In the spring of 2021, she contacted John Tye, a founder of the pro bono law firm Whistleblower Aid, for help; Tye agreed to represent her and to help protect her anonymity. In the late summer of 2021, Haugen began meeting with members of the United States Congress, including Senator Richard Blumenthal and Senator Marsha Blackburn. Starting in September 2021, The Wall Street Journal published The Facebook Files: A Wall Street Journal Investigation, a series of news reports "based on a review of internal Facebook documents, including research reports, online employee discussions and drafts of presentations to senior management." The investigation was published in nine reports, including examinations of rules exemptions for high-profile users, Facebook's impacts on youth, the impacts of its 2018 algorithm changes, weaknesses in Facebook's response to human trafficking and drug cartels, and vaccine misinformation, followed by a profile article about Haugen, given that she had gathered the documents that supported the investigative reports. Following the publication of the Wall Street Journal articles about Facebook's practices, the United States Senate Commerce Committee's Sub-Committee on Consumer Protection, Product Safety, and Data Security scheduled two hearings, with Antigone Davis, the global head of safety for Facebook, the first to be questioned, on September 30, 2021, Haugen, the hitherto-anonymous whistleblower, was questioned on October 5, 2021. On October 3, 2021, Haugen disclosed her identity as the Facebook whistleblower when she appeared on 60 Minutes. During the interview, she discussed the Facebook program known as "Civic Integrity", which had been intended to curb misinformation and other threats to election security. The program was dissolved following the 2020 elections, which Haugen stated "really feels like a betrayal of democracy to me," and which she believed contributed to the 2021 United States Capitol attack. Haugen stated: "The thing I saw at Facebook over and over again was there were conflicts of interest between what was good for the public and what was good for Facebook. And Facebook, over and over again, chose to optimize for its own interests, like making more money." Haugen had shared documents with members of the U.S. Congress and offices of various attorneys general, but not with the Federal Trade Commission. Facebook's market capitalization dropped by $6 billion within 24 hours of Haugen's October 3 60 Minutes interview and after the October 4, 2021 Facebook outage. Based on the leaked documents, Kevin Roose, writing for The New York Times, suggested Facebook might be a weaker social media company than it previously appeared to be. After Haugen publicly disclosed her identity, Pierre Omidyar's philanthropic organization, Luminate Group, began to provide support to Haugen, including help with press and government relations in Europe. At least eight complaints were filed with the Securities and Exchange Commission (SEC) by Haugen's attorneys, covering topics reported by The Wall Street Journal, and including how Facebook deals with political misinformation, hate speech, teenage mental health, human trafficking, the promotion of ethnic violence, preferential treatment of certain users, and its communications with investors. In a SEC whistleblower complaint, Haugen alleged Facebook had misled investors, given that they had misrepresented the progress they had made in tackling hate, violence and misinformation on the platform. The documents provided by Haugen to the SEC also pertained to Facebook's management of election-related misinformation in the United States after the November 2020 election. Haugen's complaint included internal Facebook documents pertaining to Facebook management of misinformation and hate speech in India. The complaint stated that many users and pages associated with the Rashtriya Swayamsevak Sangh (RSS) promoted fear-mongering and anti-Muslim narratives, with an intent to incite violence. She alleged that Facebook was well aware of the incendiary anti-Muslim narratives promoted in India. Haugen also asserted that Facebook lacked algorithms to detect hate speech in Hindi and Bengali, causing such content to be ignored. Facebook added hate speech algorithms in Hindi in 2020, and in Bengali in 2021. Public statements by Facebook CEO Mark Zuckerberg are referenced in the SEC complaints filed by Haugen, along with her allegation that Zuckerberg is ultimately responsible as CEO, since he controlled Facebook. Various public statements by Zuckerberg, including his 2020 testimony before the U.S. Congress, appear to be inconsistent with internal Facebook documents submitted by Haugen. In February 2022, Whistleblower Aid filed two SEC complaints on behalf of Haugen, alleging "material misrepresentations and omissions in statements to investors" by Facebook, related to its efforts to address climate change misinformation and COVID misinformation, based on internal Facebook documents. On October 5, 2021, Haugen testified before the United States Senate Commerce Committee's Sub-Committee on Consumer Protection, Product Safety, and Data Security. A written version of her opening statement to the U.S. Senate subcommittee was published on October 4, 2021. Haugen stated during the hearing, "The company's leadership knows how to make Facebook and Instagram safer, but won't make the necessary changes because they have put their astronomical profits before people. Congressional action is needed. They won’t solve this crisis without your help." Haugen further discussed Myanmar and Ethiopia, stating Facebook is "literally fanning ethnic violence" when engagement-based ranking is deployed without functioning integrity and security systems. Haugen also indicated she is in communication with another U.S. congressional committee about issues related to espionage and disinformation, and a reason she has not shared documents with the Federal Trade Commission is because she believes Facebook systems will "continue to be dangerous even if they're broken up." After the hearing, Senator Richard Blumenthal, chair of the Commerce subcommittee, said Haugen "wants to fix Facebook, not burn it to the ground." In the wake of Haugen's testimony, the response from Facebook CEO Mark Zuckerberg that day included "Many of the claims don't make any sense. I think most of us just don’t recognize the false picture of the company that is being painted", and "We're committed to doing the best work we can, but at some level the right body to assess trade-offs between social equities is our democratically elected Congress." A post-hearing statement from Lena Pietsch, Facebook's director of policy communications, included, "We agree on one thing. It's time to begin to create standard rules for the internet." Senator Blumenthal indicated he wanted Zuckerberg to testify before Congress regarding the documents disclosed by Haugen, and that the subcommittee might issue a subpoena to Facebook for more records. Documents disclosed by Haugen were shared with state attorneys general offices in California, Massachusetts, Vermont, Nebraska and Tennessee. On October 13, 2021, in response to disclosures made by Haugen to The Wall Street Journal, more than a dozen U.S. state attorneys general sent a letter to Facebook requesting information about the Facebook "XCheck system" that protects high-profile users and Facebook action against COVID-19 vaccine misinformation. On November 12, 2021, Ohio Attorney General Dave Yost filed a lawsuit against Meta Platforms (formerly known as Facebook) on behalf of investors, alleging repeated false representations by executives, including chief executive Mark Zuckerberg, CFO David Wehner, and global affairs and communications executive Nick Clegg, about the safety of the platform, based on documents leaked by Haugen and documents collectively known as "The Facebook Papers". The lawsuit seeks over $100 billion in damages and for the company to implement reforms. On November 18, 2021, a bipartisan group of state attorneys general announced a consumer protection investigation of Meta based on documents shared by Haugen. The investigation includes a focus on Instagram, how Meta promotes engagement, and possible harms to children and teenagers. On October 6, 2021, Haugen's attorney John Tye said the legal team and Haugen are in communication with the Federal Trade Commission, as well as the European Parliament and the French Parliament. The United States Senate Committee on Homeland Security and Governmental Affairs and the United States House Select Committee to Investigate the January 6th Attack on the United States Capitol have confirmed plans to meet with Haugen. On October 11, 2021, Facebook's Oversight Board, an external review panel which rules on select content moderation decisions of the company, announced that it would be speaking with Haugen about her experiences with the company and its practices. On October 21, 2021, Haugen met with the U.S. House Judiciary antitrust subcommittee chair David Cicilline and ranking member Ken Buck. On October 25, 2021, Haugen testified before the Parliament of the United Kingdom. During her testimony, she advocated for government regulation of Facebook, and for Facebook to make changes. On November 8, 2021, she appeared before the European Parliament in a hearing organized by the Committee on the Internal Market and Consumer Protection. In a nearly three-hour hearing, she urged the Parliament debating the Digital Services Act to mandate social media platforms to operate transparently and not to create loopholes that Big Tech could exploit. Haugen said the DSA has "the potential to be a global gold standard" and an inspiration for other countries on safeguarding democracy on social media. She emphasized how linguistically diverse Europe could force the platforms to take a systemic approach to safety, rather than focus only on content moderation and on major languages. On May 18, 2022, after the European Parliament and the Council of the European Union had reached a political agreement on the Digital Services Act, Haugen reappeared before the Parliament. She congratulated the EU lawmakers for the result and called for the European Commission and the member states to put a lot of effort into enforcing the DSA, so that it will not be "a dead letter". In June 2022, Politico reported that Haugen plans to establish a non-profit organization called "Beyond the Screen" to enhance awareness of the harms of social media. The new organization will focus on litigation and investor-based strategies in order to provide legal and economic incentives for mitigating harms. In October 2022, Haugen joined the Council for Responsible Social Media project launched by Issue One to address the negative mental, civic, and public health impacts of social media in the United States co-chaired by former House Democratic Caucus Leader Dick Gephardt and former Massachusetts Lieutenant Governor Kerry Healey. In December 2021, Little, Brown and Company announced a book deal with Haugen for her memoir. In 2023, Haugen's memoir The Power of One: How I Found the Strength to Tell the Truth and Why I Blew the Whistle on Facebook was published by Little, Brown and Company. A review in The Washington Post by Bethany McLean states, "If all Haugen’s book did was present her whistleblowing case (the legal merits of which have yet to be decided), it might still be an important part of the ongoing chronicling of how we allowed social media's dangers to creep up on us. But what really makes the book worth reading is the broader wisdom in her story (and the absence of the self-importance implied by the book's unfortunate title)." In popular media Haugen will be portrayed by Mikey Madison in an upcoming feature film The Social Reckoning, written and directed by Aaron Sorkin, and with Jeremy Strong starring as Zuckerberg. Based on a 2023 book by Jeff Horwitz, entitled Broken Code: Inside Facebook and the Fight to Expose Its Harmful Secrets, the film is to be released on October 9, 2026. Personal life In 2011, Haugen was diagnosed with celiac disease, and in 2014 while going through a divorce, she had to be hospitalized in intensive care. In 2021, Haugen told The Guardian she was motivated to focus her work at Facebook on addressing misinformation because of her experience with losing a friend, who had been hired to help with household tasks during her recovery, after the friend visited online forums and became a proponent of conspiratorial beliefs that included white nationalism and the occult. After leaving Facebook, Haugen relocated to Puerto Rico, and has invested in a cryptocurrency company. Haugen has Norwegian ancestry and was awarded an America-Norway Heritage Award from the Norway-America Association in 2022 for her work as a whistleblower. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Oxford_University_Press] | [TOKENS: 5075] |
Contents Oxford University Press Oxford University Press (OUP) is the publishing house of the University of Oxford. It is the largest university press in the world. Its first book was printed in Oxford in 1478, with the Press officially granted the legal right to print books by decree in 1586. It is the second-oldest university press after Cambridge University Press, which was founded in 1534. It is a department of the University of Oxford. It is governed by a group of 15 academics, the Delegates of the Press, appointed by the vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, opposite Somerville College, in the inner suburb of Jericho. For the last 400 years, OUP has focused primarily on the publication of pedagogical texts. It continues this tradition today by publishing academic journals, dictionaries, English language resources, bibliographies, books on Indology, music, classics, literature, and history, as well as Bibles and atlases. OUP has offices around the world, primarily in locations that were once part of the British Empire. History The University of Oxford began printing around 1480 and became a major printer of Bibles, prayer books, and scholarly works. Oxford's chancellor Archbishop William Laud consolidated the legal status of the university's printing in the 1630s and petitioned Charles I for rights that would enable Oxford to compete with the Stationers' Company and the King's Printer. He obtained a succession of royal grants, and Oxford's "Great Charter" in 1636 gave the university the right to print "all manner of books". Laud also obtained the "privilege" from the Crown of printing the King James or Authorized Version of Scripture at Oxford. This privilege created substantial returns over the next 250 years. Following the English Civil War, Vice-chancellor John Fell, Dean of Christ Church, Bishop of Oxford, and Secretary to the Delegates was determined to install printing presses in 1668, making it the university's first central print shop. In 1674, OUP began to print a broadsheet calendar, known as the Oxford Almanack, that was produced annually without interruption from 1674 to 2019. Fell drew up the first formal programme for the university's printing, which envisaged hundreds of works, including the Bible in Greek, editions of the Coptic Gospels and works of the Church Fathers, texts in Arabic and Syriac, comprehensive editions of classical philosophy, poetry, and mathematics, a wide range of medieval scholarship, and also "a history of insects, more perfect than any yet Extant." Generally speaking, the early 18th century marked a lull in the press's expansion. It suffered from the absence of any figure comparable to Fell. The business was rescued by the intervention of a single Delegate, William Blackstone. Disgusted by the chaotic state of the press and antagonized by Vice-Chancellor George Huddesford, Blackstone called for sweeping reforms that would firmly set out the Delegates' powers and obligations, officially record their deliberations and accounting, and put the print shop on an efficient footing. Nonetheless, Randolph[ambiguous] ignored this document, and it was not until Blackstone threatened legal action that changes began. The university had moved to adopt all of Blackstone's reforms by 1760. By the late 18th century, the press had become more focused. In 1825, the Delegates bought land on Walton Street. Buildings were constructed from plans drawn up by Daniel Robertson and Edward Blore, and the press moved into them in 1830. This site remains the principal office of OUP in the 21st century, at the corner of Walton Street and Great Clarendon Street, northwest of Oxford city centre. The press then entered an era of enormous change. In 1830, it was still a joint-stock printing business in an academic backwater, offering learned works to a relatively small readership of scholars and clerics At this time, Thomas Combe joined the press and became the university's Printer until he died in 1872. Combe was a better businessman than most Delegates but still no innovator: he failed to grasp the huge commercial potential of India paper, which grew into one of Oxford's most profitable trade secrets in later years. Even so, Combe earned a fortune through his shares in the business and the acquisition and renovation of the bankrupt paper mill at Wolvercote. Combe showed little interest, however, in producing fine printed work at the press. The best-known text associated with his print shop was the flawed first edition of Alice's Adventures in Wonderland, printed by Oxford at the expense of its author Lewis Carroll (Charles Lutwidge Dodgson) in 1865. It took the 1850 Royal Commission on the workings of the university and a new Secretary, Bartholomew Price, to shake up the press. Appointed in 1868, Price had already recommended to the university that the press needed an efficient executive officer to exercise "vigilant superintendence" of the business, including its dealings with Alexander Macmillan, who became the publisher for Oxford's printing in 1863 and 1866 helped Price to create the Clarendon Press series of cheap, elementary school books – perhaps the first time that Oxford used the Clarendon imprint. Under Price, the press began to take on its modern shape. Major new lines of work began. For example, in 1875, the Delegates approved the series Sacred Books of the East under the editorship of Friedrich Max Müller, bringing a vast range of religious thought to a wider readership. Equally, Price moved OUP towards publishing in its own right. The press had ended its relationship with Parker's in 1863 and, in 1870, bought a small London bindery for some Bible work. Macmillan's contract ended in 1880 and was not renewed. By this time, Oxford also had a London warehouse for Bible stock in Paternoster Row, and in 1880, its manager, Henry Frowde (1841–1927), was given the formal title of Publisher to the university. Frowde came from the book trade, not the university, and remained an enigma to many. One obituary in Oxford's staff magazine The Clarendonian admitted, "Very few of us here in Oxford had any personal knowledge of him." Despite that, Frowde became vital to OUP's growth, adding new lines of books to the business, presiding over the massive publication of the Revised Version of the New Testament in 1881 and playing a key role in setting up the press's first office outside Britain, in New York City in 1896. Price transformed OUP. In 1884, the year he retired as Secretary, the Delegates bought back the last shares in the business. The press was now owned wholly by the university, with its own paper mill, print shop, bindery, and warehouse. Its output had increased to include school books and modern scholarly texts such as James Clerk Maxwell's A Treatise on Electricity & Magnetism (1873), which proved fundamental to Einstein's thought. Without abandoning its traditions or quality of work, Price began to turn OUP into an alert, modern publisher. In 1879, he also took on the publication that led that process to its conclusion: the massive project that became the Oxford English Dictionary (OED). Offered to Oxford by James Murray and the Philological Society, the "New English Dictionary" was a grand academic and patriotic undertaking. Lengthy negotiations led to a formal contract. Murray was to edit a work estimated to take ten years and to cost approximately £9,000. Both figures were wildly optimistic. The Dictionary began appearing in print in 1884, but the first edition was not completed until 1928, 13 years after Murray's death, costing around £375,000. This vast financial burden and its implications landed on Price's successors.[citation needed] The next Secretary, Philip Lyttelton Gell, was appointed by the Vice-Chancellor Benjamin Jowett in 1884 but struggled and was finally dismissed in 1897. The Assistant Secretary, Charles Cannan, was instrumental in Gell's removal. Cannan took over with little fuss and even less affection for his predecessor in 1898: "Gell was always here, but I cannot make out what he did." By the early 20th century, OUP expanded its overseas trade, partly due to the efforts of Humphrey Milford, the publisher of the University of Oxford from 1913 to 1945. The 1920s saw skyrocketing prices of both materials and labour. Paper was hard to come by and had to be imported from South America through trading companies. Economies and markets slowly recovered as the 1920s progressed. In 1928, the press's imprint read 'London, Edinburgh, Glasgow, Leipzig, Toronto, Melbourne, Cape Town, Bombay, Calcutta, Madras and Shanghai'. Not all of these were full-fledged branches: in Leipzig, there was a depot run by H. Bohun Beet, and in Canada and Australia, there were small, functional depots in the cities and an army of educational representatives penetrating the rural fastnesses to sell the press's stock as well as books published by firms whose agencies were held by the press, very often including fiction and light reading. In India, the Branch depots in Bombay, Madras, and Calcutta were imposing establishments with sizeable stock inventories, for the Presidencies themselves were large markets, and the educational representatives there dealt mostly with upcountry trade. In 1923, OUP established a Music Department. At the time, such musical publishing enterprises, however, were rare. and few of the Delegates or former Publishers were themselves musical or had extensive music backgrounds.[citation needed] OUP bought an Anglo-French Music Company and all its facilities, connections, and resources. This concentration provided OUP two mutually reinforcing benefits: a niche in music publishing unoccupied by potential competitors and a branch of music performance and composition that the English themselves had largely neglected. Hinnells proposes that the early Music Department's "mixture of scholarship and cultural nationalism" in an area of music with largely unknown commercial prospects was driven by its sense of cultural philanthropy (given the press's academic background) and a desire to promote "national music outside the German mainstream." It was not until 1939 that the Music Department showed its first profitable year. The Depression of 1929 dried profits from the Americas to a trickle, and India became 'the one bright spot' in an otherwise dismal picture. Bombay was the nodal point for distribution to the Africas and onward sale to Australasia, and people who trained at the three major depots later moved to pioneer branches in Africa and Southeast Asia. In 1927–1934 Oxford University Press, Inc., New York, was reorganized by Geoffrey Cumberlege to return it to profitability from the lows of the Depression years. (In 1945–1956, Cumberlege would succeed Milford as publisher to the University of Oxford). The period following World War II saw consolidation in the face of the break-up of the Empire and the post-war reorganization of the Commonwealth.[citation needed] In the 1960s, OUP Southern Africa started publishing local authors for the general reader, but also for schools and universities, under its Three Crowns Books imprint. Its territory includes Botswana, Lesotho, Swaziland, and Namibia, as well as South Africa, the biggest market of the five.[citation needed] OUP Southern Africa is now one of the three biggest educational publishers in South Africa. It focuses on publishing textbooks, dictionaries, atlases, supplementary material for schools, and university textbooks. Its author base is overwhelmingly local, and in 2008, it partnered with the university to support scholarships for South Africans studying postgraduate degrees.[citation needed] Operations in South Asia and East and South East Asia were and, in the case of the former, remain significant parts of the company. Today, the North American branch in New York City is primarily a distribution branch to facilitate the sale of Oxford Bibles in the United States. It also handles marketing of all books of its parent, Macmillan.[citation needed] By the end of 2021, OUP USA had published eighteen Pulitzer Prize–winning books. In March 2020, during the COVID-19 pandemic its Bookshop on the High Street closed. On 27 August 2021, OUP closed Oxuniprint, its printing division. The closure will mark the "final chapter" of OUP's centuries-long history of printing. Museum The Oxford University Press Museum is located on Great Clarendon Street, Oxford. Visits must be booked in advance and are led by an archive staff member. Displays include a 19th-century printing press, the OUP buildings, and the printing and history of the Oxford Almanack, Alice in Wonderland and the Oxford English Dictionary.[citation needed] OUP came to be known as "(The) Clarendon Press" when printing moved from the Sheldonian Theatre to the Clarendon Building in Broad Street in 1713. The name continued to be used when OUP moved to its present site in Oxford in 1830. The label "Clarendon Press" took on a new meaning when OUP began publishing books through its London office in the early 20th century. To distinguish the two offices, London books were labelled "Oxford University Press" publications, while those from Oxford were labelled "Clarendon Press" books. This labelling ceased in the 1970s when the London office of OUP closed. Today, OUP reserves "Clarendon Press" as an imprint for Oxford publications of particular academic importance. Scholarly journals OUP as Oxford Journals has also been a major publisher of academic journals, both in the sciences and the humanities; as of 2024[update] it publishes more than 500 journals on behalf of learned societies around the world. It has been noted as one of the first university presses to publish an open access journal (Nucleic Acids Research), and probably the first to introduce so-called hybrid open access journals, offering "optional open access" to authors, which provides all readers with online access to their paper free of charge. The "Oxford Open" model applies to the majority of their journals. OUP is a member of the Open Access Scholarly Publishers Association. OUP is a signatory of the SDG Publishers Compact, and has taken steps to support the achievement of the Sustainable Development Goals (SDGs) in the publishing industry. These include the publishing of a new series of Oxford Open Journals, including Oxford Open Climate Change, Oxford Open Energy, Oxford Open Immunology, Oxford Open Infrastructure and Health, and Oxford Open Digital Health. Series and titles Oxford University Press publishes a variety of dictionaries (e.g. Oxford English Dictionary, Shorter Oxford English Dictionary, Compact Oxford English Dictionary, Compact Editions of the Oxford English Dictionary, Compact Oxford English Dictionary of Current English, Concise Oxford English Dictionary, Oxford Dictionary of Marketing, Oxford Advanced Learner's Dictionary), English as a second or foreign language resources (e.g. Let's Go), English language exams (e.g. Oxford Test of English and the Oxford Placement Test), bibliographies (e.g., Oxford Bibliographies Online), miscellaneous series such as Very Short Introductions, and books on Indology, music, classics, literature, history, Bibles, and atlases. Many of these are published under the Oxford Languages brand. Clarendon Scholarships Since 2001, Oxford University Press has financially supported the Clarendon bursary, a University of Oxford graduate scholarship scheme. Controversies In February 1989, Iran's Ayatollah Khomeini issued a fatwa urging the execution of British author Salman Rushdie and of all involved in the publication of his novel The Satanic Verses. Rushdie went into hiding, and an international movement began to boycott book trading with Iran. There was, therefore, outrage when, in April 1989, OUP broke the worldwide embargo and chose to attend the Tehran Book Fair. OUP justified this by saying, "We deliberated about it quite deeply but felt it certainly wasn't in our interests, or Iran's as a whole, to stay away." The New York Times and The Sunday Times both condemned Oxford's decision. In 1990, in the UK Court of Appeal, author Andrew Malcolm won a landmark legal judgment against Oxford University (Press) for its breach of a contract to publish his philosophical text Making Names. Reporting on the verdict in The Observer, Laurence Marks wrote, "It is the first time in living memory that Grub Street has won such a victory over its oppressors". The Appeal Court judges were highly critical of Oxford's conduct of the affair and the litigation. The case ended in July 1992 with a Tomlin order, a damages settlement under which the servants and agents of Oxford University are permanently barred from denigrating Malcolm or Making Names, rendering it the first book in literary history to be afforded such legal protection. The case was reported to have cost Oxford over £500,000. In November 1998, OUP announced the closure, on commercial grounds, of its modern poetry list. Andrew Potter, OUP's director of music, trade paperbacks and Bibles, told The Times that the list "just about breaks even. The university expects us to operate on commercial grounds, especially in this day and age." In the same article, the poet D. J. Enright, who had been with OUP since 1979, said, "There was no warning. It was presented as a fait accompli. Even the poetry editor didn't know....The money involved is peanuts. It's a good list, built up over many years." In February 1999, Arts Minister Alan Howarth made a speech in Oxford in which he denounced the closure: "OUP is not merely a business. It is a department of the University of Oxford and has charitable status. It is part of a great university, which the Government supports financially and which exists to develop and transmit our intellectual culture....It is a perennial complaint by the English faculty that the barbarians are at the gate. Indeed they always are. But we don't expect the gatekeepers themselves, the custodians, to be barbarians." Oxford's professor Valentine Cunningham wrote in the Times Higher Education Supplement: "Increasingly, (OUP) has behaved largely like a commercial outfit, with pound signs in its eyes and a readiness to dumb down for the sake of popularity and sales....Sacking poets not because they lose money but because they do not make enough of it: it is an allegory of a university press missing the point, mistaking its prime purpose." In March 1999 The Times Literary Supplement commissioned Andrew Malcolm to write an article under the strapline "Why the present constitution of the OUP cannot work". A decade later, OUP's managing director, Ivon Asquith, reflected on the public relations damage caused by the episode: "If I had foreseen the self-inflicted wound we would suffer I would not have let the proposal get as far as the Finance Committee." Since the 1940s, both OUP and the Cambridge University Press (CUP), had made applications to the Inland Revenue for exemption from corporate tax. The first application, by CUP in 1940, was rejected "on the ground that, since the Press was printing and publishing for the outside world and not simply for the internal use of the University, the Press's trade went beyond the purpose and objects of the University and (in terms of the Act) was not exercised in the course of the actual carrying out of a primary purpose of the University." Similar applications by OUP in 1944 and 1950 were also rejected by the Inland Revenue, whose officers repeatedly pointed out that the university presses were in open competition with commercial, tax-liable publishers. In November 1975, CUP's chief executive Geoffrey Cass again applied to the Inland Revenue, and a year later, CUP's tax exemption was quietly conceded. OUP's Chief Executive George Richardson followed suit in 1977. OUP's tax exemption was granted in 1978. The decisions were not made public. The issue was only brought to public attention due to press interest in OUP following the poetry list closure controversy. In 1999, the campaigner Andrew Malcolm published his second book, The Remedy, where he alleged that OUP breached its 1978 tax-exemption conditions. This was reported in a front-page article in The Oxford Times, along with OUP's response. In March 2001, after a 28-year battle with the Indian tax authorities, OUP lost its tax exemption in India. The Supreme Court ruled that OUP was not tax exempt in the subcontinent "because it does not carry out any university activities there but acts simply as a commercial publisher". To pay off back taxes, owed since the 1970s, OUP was obliged to sell its Mumbai headquarters building, Oxford House. The Bookseller reported that "The case has again raised questions about OUP's status in the UK". In 2003, Joel Rickett of The Bookseller wrote an article in The Guardian describing the resentment of commercial rivals at OUP's tax exemption. Rickett accurately predicted that the funds which would have been paid in tax were "likely to be used to confirm OUP's dominance by buying up other publishers." Between 1989 and 2018, OUP bought out over 70 rival book and journal publishers. In 2007, with the new "public benefit" requirement of the revised Charities Act, the issue was re-examined with particular reference to OUP. In the same year, Malcolm obtained and posted the documents of OUP's applications to the Inland Revenue for tax exemption in the 1940s and 1950s (unsuccessful) and the 1970s (successful). In 2008, CUP's and OUP's privilege was attacked by rival publishers. In 2009, The Guardian invited Andrew Malcolm to write an article on the subject. In July 2012, the UK's Serious Fraud Office found OUP's branches in Kenya and Tanzania guilty of bribery to obtain school bookselling contracts sponsored by the World Bank. Oxford was fined £1.9 million "in recognition of sums it received which were generated through unlawful conduct" and barred from applying for World Bank-financed projects for three years. In December 2023, concerns were raised that OUP had published an academic paper based on genetic data taken from the Uyghur population of Xinjiang, a Turkic ethnic group in China. Rhys Blakely, a science correspondent for The Times, reported: "The research has been published online by Oxford University Press (OUP) in a journal that receives financial support from China's Ministry of Justice. The highly unusual deal will raise fears that Oxford risks becoming entangled in human rights abuses against the Uighur community. It will also add to concerns over China's efforts to influence UK academia." In February, OUP announced that it was carrying out internal investigations into two further studies, based on DNA taken from China's Xibe ethnic minority. On 17 May, The Times reported that Oxford had retracted the two studies, quoting a statement from the OUP: "Earlier this year, we were alerted to concerns regarding two papers in Forensics Sciences Research. Based on the information we received, we undertook further investigation and took the decision to retract the papers, in line with industry standard processes." In July 2025, OUP ended its publication of Forensic Sciences Research (FSR), a journal sponsored by China's Ministry of Justice, following ethical concerns related to research involving DNA data from Uyghur and other ethnic minorities in China. Critics raised issues about the lack of meaningful consent from participants, particularly in regions like Xinjiang, where state surveillance and coercion are prevalent. Several studies published in the journal were conducted or funded by Chinese police and security agencies, raising questions about the independence and ethical standards of the research. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Black_hole#cite_note-16] | [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 |
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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 |
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Contents URL A uniform resource locator (URL), colloquially known as web address, is a reference to a resource on the World Wide Web. A URL specifies the location of a resource on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifier (URI), although many people use the two terms interchangeably.[a] A URL is most commonly used to reference a web page (HTTP/HTTPS) but is also used for file transfer (FTP), email (mailto), database access (JDBC), and many other applications. Most web browsers display the URL of a web page above the page in an address bar. As an example of a web page URL, https://www.example.com/index.html indicates protocol https, hostname www.example.com, and file name index.html. History The Uniform Resource Locator was defined in RFC 1738 in 1994 by Tim Berners-Lee, the inventor of the World Wide Web, and the URI working group of the Internet Engineering Task Force (IETF), as an outcome of collaboration started at the IETF Living Documents birds of a feather session in 1992. The format combines the pre-existing system of domain names (created in 1985) with file path syntax, where slashes are used to separate directory and filenames. Conventions already existed where server names could be prefixed to complete file paths, preceded by a double slash (//). Berners-Lee later expressed regret at the use of dots to separate the parts of the domain name within URIs, wishing he had used slashes throughout, and also said that, given the colon following the first component of a URI, the two slashes before the domain name were unnecessary. Early WorldWideWeb collaborators, including Berners-Lee, originally proposed the use of UDIs: Universal Document Identifiers. An early (1993) draft of the HTML Specification referred to "Universal" Resource Locators. This was dropped some time between June 1994 and October 1994. In his book Weaving the Web, Berners-Lee emphasizes his preference for the original inclusion of "universal" in the expansion rather than the word "uniform", to which it was later changed, and he gives a brief account of the contention that led to the change. Syntax Every HTTP URL conforms to the syntax of a generic URI. The URI generic syntax consists of five components organized hierarchically in order of decreasing significance from left to right:: §3 A component is undefined if it has an associated delimiter and the delimiter does not appear in the URI; the scheme and path components are always defined.: §5.2.1 A component is empty if it has no characters; the scheme component is always non-empty.: §3 The authority component consists of subcomponents: This is represented in a syntax diagram as: The URI comprises: A web browser will usually dereference a URL by performing an HTTP request to the specified host, by default on port number 80. URLs using the https scheme require that requests and responses be made over a secure connection to the website. Internationalized URL Internet users are distributed throughout the world using a wide variety of languages and alphabets, and expect to be able to create URLs in their own local alphabets. An Internationalized Resource Identifier (IRI) is a form of URL that includes Unicode characters. All modern browsers support IRIs. The parts of the URL requiring special treatment for different alphabets are the domain name and path. The domain name in the IRI is known as an Internationalized Domain Name (IDN). Web and Internet software automatically convert the domain name into punycode usable by the Domain Name System; for example, the Chinese URL http://例子.卷筒纸 becomes http://xn--fsqu00a.xn--3lr804guic/. The xn-- indicates that the character was not originally ASCII. The URL path name can also be specified by the user in the local writing system. If not already encoded, it is converted to UTF-8, and any characters not part of the basic URL character set are escaped as hexadecimal using percent-encoding; for example, the Japanese URL http://example.com/引き割り.html becomes http://example.com/%E5%BC%95%E3%81%8D%E5%89%B2%E3%82%8A.html. The target computer decodes the address and displays the page. Protocol-relative URLs Protocol-relative links (PRL), also known as protocol-relative URLs (PRURL), are URLs that have no protocol specified. For example, //example.com will use the protocol of the current page, typically HTTP or HTTPS. See also Notes Citations References External links |
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Contents URL A uniform resource locator (URL), colloquially known as web address, is a reference to a resource on the World Wide Web. A URL specifies the location of a resource on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifier (URI), although many people use the two terms interchangeably.[a] A URL is most commonly used to reference a web page (HTTP/HTTPS) but is also used for file transfer (FTP), email (mailto), database access (JDBC), and many other applications. Most web browsers display the URL of a web page above the page in an address bar. As an example of a web page URL, https://www.example.com/index.html indicates protocol https, hostname www.example.com, and file name index.html. History The Uniform Resource Locator was defined in RFC 1738 in 1994 by Tim Berners-Lee, the inventor of the World Wide Web, and the URI working group of the Internet Engineering Task Force (IETF), as an outcome of collaboration started at the IETF Living Documents birds of a feather session in 1992. The format combines the pre-existing system of domain names (created in 1985) with file path syntax, where slashes are used to separate directory and filenames. Conventions already existed where server names could be prefixed to complete file paths, preceded by a double slash (//). Berners-Lee later expressed regret at the use of dots to separate the parts of the domain name within URIs, wishing he had used slashes throughout, and also said that, given the colon following the first component of a URI, the two slashes before the domain name were unnecessary. Early WorldWideWeb collaborators, including Berners-Lee, originally proposed the use of UDIs: Universal Document Identifiers. An early (1993) draft of the HTML Specification referred to "Universal" Resource Locators. This was dropped some time between June 1994 and October 1994. In his book Weaving the Web, Berners-Lee emphasizes his preference for the original inclusion of "universal" in the expansion rather than the word "uniform", to which it was later changed, and he gives a brief account of the contention that led to the change. Syntax Every HTTP URL conforms to the syntax of a generic URI. The URI generic syntax consists of five components organized hierarchically in order of decreasing significance from left to right:: §3 A component is undefined if it has an associated delimiter and the delimiter does not appear in the URI; the scheme and path components are always defined.: §5.2.1 A component is empty if it has no characters; the scheme component is always non-empty.: §3 The authority component consists of subcomponents: This is represented in a syntax diagram as: The URI comprises: A web browser will usually dereference a URL by performing an HTTP request to the specified host, by default on port number 80. URLs using the https scheme require that requests and responses be made over a secure connection to the website. Internationalized URL Internet users are distributed throughout the world using a wide variety of languages and alphabets, and expect to be able to create URLs in their own local alphabets. An Internationalized Resource Identifier (IRI) is a form of URL that includes Unicode characters. All modern browsers support IRIs. The parts of the URL requiring special treatment for different alphabets are the domain name and path. The domain name in the IRI is known as an Internationalized Domain Name (IDN). Web and Internet software automatically convert the domain name into punycode usable by the Domain Name System; for example, the Chinese URL http://例子.卷筒纸 becomes http://xn--fsqu00a.xn--3lr804guic/. The xn-- indicates that the character was not originally ASCII. The URL path name can also be specified by the user in the local writing system. If not already encoded, it is converted to UTF-8, and any characters not part of the basic URL character set are escaped as hexadecimal using percent-encoding; for example, the Japanese URL http://example.com/引き割り.html becomes http://example.com/%E5%BC%95%E3%81%8D%E5%89%B2%E3%82%8A.html. The target computer decodes the address and displays the page. Protocol-relative URLs Protocol-relative links (PRL), also known as protocol-relative URLs (PRURL), are URLs that have no protocol specified. For example, //example.com will use the protocol of the current page, typically HTTP or HTTPS. See also Notes Citations References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Elon_Musk#cite_note-bloomberg.com-252] | [TOKENS: 10515] |
Contents Elon Musk Elon Reeve Musk (/ˈiːlɒn/ EE-lon; born June 28, 1971) is a businessman and entrepreneur known for his leadership of Tesla, SpaceX, Twitter, and xAI. Musk has been the wealthiest person in the world since 2025; as of February 2026,[update] Forbes estimates his net worth to be around US$852 billion. Born into a wealthy family in Pretoria, South Africa, Musk emigrated in 1989 to Canada; he has Canadian citizenship since his mother was born there. He received bachelor's degrees in 1997 from the University of Pennsylvania before moving to California to pursue business ventures. In 1995, Musk co-founded the software company Zip2. Following its sale in 1999, he co-founded X.com, an online payment company that later merged to form PayPal, which was acquired by eBay in 2002. Musk also became an American citizen in 2002. In 2002, Musk founded the space technology company SpaceX, becoming its CEO and chief engineer; the company has since led innovations in reusable rockets and commercial spaceflight. Musk joined the automaker Tesla as an early investor in 2004 and became its CEO and product architect in 2008; it has since become a leader in electric vehicles. In 2015, he co-founded OpenAI to advance artificial intelligence (AI) research, but later left; growing discontent with the organization's direction and their leadership in the AI boom in the 2020s led him to establish xAI, which became a subsidiary of SpaceX in 2026. In 2022, he acquired the social network Twitter, implementing significant changes, and rebranding it as X in 2023. His other businesses include the neurotechnology company Neuralink, which he co-founded in 2016, and the tunneling company the Boring Company, which he founded in 2017. In November 2025, a Tesla pay package worth $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Musk was the largest donor in the 2024 U.S. presidential election, where he supported Donald Trump. After Trump was inaugurated as president in early 2025, Musk served as Senior Advisor to the President and as the de facto head of the Department of Government Efficiency (DOGE). After a public feud with Trump, Musk left the Trump administration and returned to managing his companies. Musk is a supporter of global far-right figures, causes, and political parties. His political activities, views, and statements have made him a polarizing figure. Musk has been criticized for COVID-19 misinformation, promoting conspiracy theories, and affirming antisemitic, racist, and transphobic comments. His acquisition of Twitter was controversial due to a subsequent increase in hate speech and the spread of misinformation on the service, following his pledge to decrease censorship. His role in the second Trump administration attracted public backlash, particularly in response to DOGE. The emails he sent to Jeffrey Epstein are included in the Epstein files, which were published between 2025–26 and became a topic of worldwide debate. Early life Elon Reeve Musk was born on June 28, 1971, in Pretoria, South Africa's administrative capital. He is of British and Pennsylvania Dutch ancestry. His mother, Maye (née Haldeman), is a model and dietitian born in Saskatchewan, Canada, and raised in South Africa. Musk therefore holds both South African and Canadian citizenship from birth. His father, Errol Musk, is a South African electromechanical engineer, pilot, sailor, consultant, emerald dealer, and property developer, who partly owned a rental lodge at Timbavati Private Nature Reserve. His maternal grandfather, Joshua N. Haldeman, who died in a plane crash when Elon was a toddler, was an American-born Canadian chiropractor, aviator and political activist in the technocracy movement who moved to South Africa in 1950. Elon has a younger brother, Kimbal, a younger sister, Tosca, and four paternal half-siblings. Musk was baptized as a child in the Anglican Church of Southern Africa. Despite both Elon and Errol previously stating that Errol was a part owner of a Zambian emerald mine, in 2023, Errol recounted that the deal he made was to receive "a portion of the emeralds produced at three small mines". Errol was elected to the Pretoria City Council as a representative of the anti-apartheid Progressive Party and has said that his children shared their father's dislike of apartheid. After his parents divorced in 1979, Elon, aged around 9, chose to live with his father because Errol Musk had an Encyclopædia Britannica and a computer. Elon later regretted his decision and became estranged from his father. Elon has recounted trips to a wilderness school that he described as a "paramilitary Lord of the Flies" where "bullying was a virtue" and children were encouraged to fight over rations. In one incident, after an altercation with a fellow pupil, Elon was thrown down concrete steps and beaten severely, leading to him being hospitalized for his injuries. Elon described his father berating him after he was discharged from the hospital. Errol denied berating Elon and claimed, "The [other] boy had just lost his father to suicide, and Elon had called him stupid. Elon had a tendency to call people stupid. How could I possibly blame that child?" Elon was an enthusiastic reader of books, and had attributed his success in part to having read The Lord of the Rings, the Foundation series, and The Hitchhiker's Guide to the Galaxy. At age ten, he developed an interest in computing and video games, teaching himself how to program from the VIC-20 user manual. At age twelve, Elon sold his BASIC-based game Blastar to PC and Office Technology magazine for approximately $500 (equivalent to $1,600 in 2025). Musk attended Waterkloof House Preparatory School, Bryanston High School, and then Pretoria Boys High School, where he graduated. Musk was a decent but unexceptional student, earning a 61/100 in Afrikaans and a B on his senior math certification. Musk applied for a Canadian passport through his Canadian-born mother to avoid South Africa's mandatory military service, which would have forced him to participate in the apartheid regime, as well as to ease his path to immigration to the United States. While waiting for his application to be processed, he attended the University of Pretoria for five months. Musk arrived in Canada in June 1989, connected with a second cousin in Saskatchewan, and worked odd jobs, including at a farm and a lumber mill. In 1990, he entered Queen's University in Kingston, Ontario. Two years later, he transferred to the University of Pennsylvania, where he studied until 1995. Although Musk has said that he earned his degrees in 1995, the University of Pennsylvania did not award them until 1997 – a Bachelor of Arts in physics and a Bachelor of Science in economics from the university's Wharton School. He reportedly hosted large, ticketed house parties to help pay for tuition, and wrote a business plan for an electronic book-scanning service similar to Google Books. In 1994, Musk held two internships in Silicon Valley: one at energy storage startup Pinnacle Research Institute, which investigated electrolytic supercapacitors for energy storage, and another at Palo Alto–based startup Rocket Science Games. In 1995, he was accepted to a graduate program in materials science at Stanford University, but did not enroll. Musk decided to join the Internet boom of the 1990s, applying for a job at Netscape, to which he reportedly never received a response. The Washington Post reported that Musk lacked legal authorization to remain and work in the United States after failing to enroll at Stanford. In response, Musk said he was allowed to work at that time and that his student visa transitioned to an H1-B. According to numerous former business associates and shareholders, Musk said he was on a student visa at the time. Business career In 1995, Musk, his brother Kimbal, and Greg Kouri founded the web software company Zip2 with funding from a group of angel investors. They housed the venture at a small rented office in Palo Alto. Replying to Rolling Stone, Musk denounced the notion that they started their company with funds borrowed from Errol Musk, but in a tweet, he recognized that his father contributed 10% of a later funding round. The company developed and marketed an Internet city guide for the newspaper publishing industry, with maps, directions, and yellow pages. According to Musk, "The website was up during the day and I was coding it at night, seven days a week, all the time." To impress investors, Musk built a large plastic structure around a standard computer to create the impression that Zip2 was powered by a small supercomputer. The Musk brothers obtained contracts with The New York Times and the Chicago Tribune, and persuaded the board of directors to abandon plans for a merger with CitySearch. Musk's attempts to become CEO were thwarted by the board. Compaq acquired Zip2 for $307 million in cash in February 1999 (equivalent to $590,000,000 in 2025), and Musk received $22 million (equivalent to $43,000,000 in 2025) for his 7-percent share. In 1999, Musk co-founded X.com, an online financial services and e-mail payment company. The startup was one of the first federally insured online banks, and, in its initial months of operation, over 200,000 customers joined the service. The company's investors regarded Musk as inexperienced and replaced him with Intuit CEO Bill Harris by the end of the year. The following year, X.com merged with online bank Confinity to avoid competition. Founded by Max Levchin and Peter Thiel, Confinity had its own money-transfer service, PayPal, which was more popular than X.com's service. Within the merged company, Musk returned as CEO. Musk's preference for Microsoft software over Unix created a rift in the company and caused Thiel to resign. Due to resulting technological issues and lack of a cohesive business model, the board ousted Musk and replaced him with Thiel in 2000.[b] Under Thiel, the company focused on the PayPal service and was renamed PayPal in 2001. In 2002, PayPal was acquired by eBay for $1.5 billion (equivalent to $2,700,000,000 in 2025) in stock, of which Musk—the largest shareholder with 11.72% of shares—received $175.8 million (equivalent to $320,000,000 in 2025). In 2017, Musk purchased the domain X.com from PayPal for an undisclosed amount, stating that it had sentimental value. In 2001, Musk became involved with the nonprofit Mars Society and discussed funding plans to place a growth-chamber for plants on Mars. Seeking a way to launch the greenhouse payloads into space, Musk made two unsuccessful trips to Moscow to purchase intercontinental ballistic missiles (ICBMs) from Russian companies NPO Lavochkin and Kosmotras. Musk instead decided to start a company to build affordable rockets. With $100 million of his early fortune, (equivalent to $180,000,000 in 2025) Musk founded SpaceX in May 2002 and became the company's CEO and Chief Engineer. SpaceX attempted its first launch of the Falcon 1 rocket in 2006. Although the rocket failed to reach Earth orbit, it was awarded a Commercial Orbital Transportation Services program contract from NASA, then led by Mike Griffin. After two more failed attempts that nearly caused Musk to go bankrupt, SpaceX succeeded in launching the Falcon 1 into orbit in 2008. Later that year, SpaceX received a $1.6 billion NASA contract (equivalent to $2,400,000,000 in 2025) for Falcon 9-launched Dragon spacecraft flights to the International Space Station (ISS), replacing the Space Shuttle after its 2011 retirement. In 2012, the Dragon vehicle docked with the ISS, a first for a commercial spacecraft. Working towards its goal of reusable rockets, in 2015 SpaceX successfully landed the first stage of a Falcon 9 on a land platform. Later landings were achieved on autonomous spaceport drone ships, an ocean-based recovery platform. In 2018, SpaceX launched the Falcon Heavy; the inaugural mission carried Musk's personal Tesla Roadster as a dummy payload. Since 2019, SpaceX has been developing Starship, a reusable, super heavy-lift launch vehicle intended to replace the Falcon 9 and Falcon Heavy. In 2020, SpaceX launched its first crewed flight, the Demo-2, becoming the first private company to place astronauts into orbit and dock a crewed spacecraft with the ISS. In 2024, NASA awarded SpaceX an $843 million (equivalent to $865,000,000 in 2025) contract to build a spacecraft that NASA will use to deorbit the ISS at the end of its lifespan. In 2015, SpaceX began development of the Starlink constellation of low Earth orbit satellites to provide satellite Internet access. After the launch of prototype satellites in 2018, the first large constellation was deployed in May 2019. As of May 2025[update], over 7,600 Starlink satellites are operational, comprising 65% of all operational Earth satellites. The total cost of the decade-long project to design, build, and deploy the constellation was estimated by SpaceX in 2020 to be $10 billion (equivalent to $12,000,000,000 in 2025).[c] During the Russian invasion of Ukraine, Musk provided free Starlink service to Ukraine, permitting Internet access and communication at a yearly cost to SpaceX of $400 million (equivalent to $440,000,000 in 2025). However, Musk refused to block Russian state media on Starlink. In 2023, Musk denied Ukraine's request to activate Starlink over Crimea to aid an attack against the Russian navy, citing fears of a nuclear response. Tesla, Inc., originally Tesla Motors, was incorporated in July 2003 by Martin Eberhard and Marc Tarpenning. Both men played active roles in the company's early development prior to Musk's involvement. Musk led the Series A round of investment in February 2004; he invested $6.35 million (equivalent to $11,000,000 in 2025), became the majority shareholder, and joined Tesla's board of directors as chairman. Musk took an active role within the company and oversaw Roadster product design, but was not deeply involved in day-to-day business operations. Following a series of escalating conflicts in 2007 and the 2008 financial crisis, Eberhard was ousted from the firm.[page needed] Musk assumed leadership of the company as CEO and product architect in 2008. A 2009 lawsuit settlement with Eberhard designated Musk as a Tesla co-founder, along with Tarpenning and two others. Tesla began delivery of the Roadster, an electric sports car, in 2008. With sales of about 2,500 vehicles, it was the first mass production all-electric car to use lithium-ion battery cells. Under Musk, Tesla has since launched several well-selling electric vehicles, including the four-door sedan Model S (2012), the crossover Model X (2015), the mass-market sedan Model 3 (2017), the crossover Model Y (2020), and the pickup truck Cybertruck (2023). In May 2020, Musk resigned as chairman of the board as part of the settlement of a lawsuit from the SEC over him tweeting that funding had been "secured" for potentially taking Tesla private. The company has also constructed multiple lithium-ion battery and electric vehicle factories, called Gigafactories. Since its initial public offering in 2010, Tesla stock has risen significantly; it became the most valuable carmaker in summer 2020, and it entered the S&P 500 later that year. In October 2021, it reached a market capitalization of $1 trillion (equivalent to $1,200,000,000,000 in 2025), the sixth company in U.S. history to do so. Musk provided the initial concept and financial capital for SolarCity, which his cousins Lyndon and Peter Rive founded in 2006. By 2013, SolarCity was the second largest provider of solar power systems in the United States. In 2014, Musk promoted the idea of SolarCity building an advanced production facility in Buffalo, New York, triple the size of the largest solar plant in the United States. Construction of the factory started in 2014 and was completed in 2017. It operated as a joint venture with Panasonic until early 2020. Tesla acquired SolarCity for $2 billion in 2016 (equivalent to $2,700,000,000 in 2025) and merged it with its battery unit to create Tesla Energy. The deal's announcement resulted in a more than 10% drop in Tesla's stock price; at the time, SolarCity was facing liquidity issues. Multiple shareholder groups filed a lawsuit against Musk and Tesla's directors, stating that the purchase of SolarCity was done solely to benefit Musk and came at the expense of Tesla and its shareholders. Tesla directors settled the lawsuit in January 2020, leaving Musk the sole remaining defendant. Two years later, the court ruled in Musk's favor. In 2016, Musk co-founded Neuralink, a neurotechnology startup, with an investment of $100 million. Neuralink aims to integrate the human brain with artificial intelligence (AI) by creating devices that are embedded in the brain. Such technology could enhance memory or allow the devices to communicate with software. The company also hopes to develop devices to treat neurological conditions like spinal cord injuries. In 2022, Neuralink announced that clinical trials would begin by the end of the year. In September 2023, the Food and Drug Administration approved Neuralink to initiate six-year human trials. Neuralink has conducted animal testing on macaques at the University of California, Davis. In 2021, the company released a video in which a macaque played the video game Pong via a Neuralink implant. The company's animal trials—which have caused the deaths of some monkeys—have led to claims of animal cruelty. The Physicians Committee for Responsible Medicine has alleged that Neuralink violated the Animal Welfare Act. Employees have complained that pressure from Musk to accelerate development has led to botched experiments and unnecessary animal deaths. In 2022, a federal probe was launched into possible animal welfare violations by Neuralink.[needs update] In 2017, Musk founded the Boring Company to construct tunnels; he also revealed plans for specialized, underground, high-occupancy vehicles that could travel up to 150 miles per hour (240 km/h) and thus circumvent above-ground traffic in major cities. Early in 2017, the company began discussions with regulatory bodies and initiated construction of a 30-foot (9.1 m) wide, 50-foot (15 m) long, and 15-foot (4.6 m) deep "test trench" on the premises of SpaceX's offices, as that required no permits. The Los Angeles tunnel, less than two miles (3.2 km) in length, debuted to journalists in 2018. It used Tesla Model Xs and was reported to be a rough ride while traveling at suboptimal speeds. Two tunnel projects announced in 2018, in Chicago and West Los Angeles, have been canceled. A tunnel beneath the Las Vegas Convention Center was completed in early 2021. Local officials have approved further expansions of the tunnel system. April 14, 2022 In early 2017, Musk expressed interest in buying Twitter and had questioned the platform's commitment to freedom of speech. By 2022, Musk had reached 9.2% stake in the company, making him the largest shareholder.[d] Musk later agreed to a deal that would appoint him to Twitter's board of directors and prohibit him from acquiring more than 14.9% of the company. Days later, Musk made a $43 billion offer to buy Twitter. By the end of April Musk had successfully concluded his bid for approximately $44 billion. This included approximately $12.5 billion in loans and $21 billion in equity financing. Having backtracked on his initial decision, Musk bought the company on October 27, 2022. Immediately after the acquisition, Musk fired several top Twitter executives including CEO Parag Agrawal; Musk became the CEO instead. Under Elon Musk, Twitter instituted monthly subscriptions for a "blue check", and laid off a significant portion of the company's staff. Musk lessened content moderation and hate speech also increased on the platform after his takeover. In late 2022, Musk released internal documents relating to Twitter's moderation of Hunter Biden's laptop controversy in the lead-up to the 2020 presidential election. Musk also promised to step down as CEO after a Twitter poll, and five months later, Musk stepped down as CEO and transitioned his role to executive chairman and chief technology officer (CTO). Despite Musk stepping down as CEO, X continues to struggle with challenges such as viral misinformation, hate speech, and antisemitism controversies. Musk has been accused of trying to silence some of his critics such as Twitch streamer Asmongold, who criticized him during one of his streams. Musk has been accused of removing their accounts' blue checkmarks, which hinders visibility and is considered a form of shadow banning, or suspending their accounts without justification. Other activities In August 2013, Musk announced plans for a version of a vactrain, and assigned engineers from SpaceX and Tesla to design a transport system between Greater Los Angeles and the San Francisco Bay Area, at an estimated cost of $6 billion. Later that year, Musk unveiled the concept, dubbed the Hyperloop, intended to make travel cheaper than any other mode of transport for such long distances. In December 2015, Musk co-founded OpenAI, a not-for-profit artificial intelligence (AI) research company aiming to develop artificial general intelligence, intended to be safe and beneficial to humanity. Musk pledged $1 billion of funding to the company, and initially gave $50 million. In 2018, Musk left the OpenAI board. Since 2018, OpenAI has made significant advances in machine learning. In July 2023, Musk launched the artificial intelligence company xAI, which aims to develop a generative AI program that competes with existing offerings like OpenAI's ChatGPT. Musk obtained funding from investors in SpaceX and Tesla, and xAI hired engineers from Google and OpenAI. December 16, 2022 Musk uses a private jet owned by Falcon Landing LLC, a SpaceX-linked company, and acquired a second jet in August 2020. His heavy use of the jets and the consequent fossil fuel usage have received criticism. Musk's flight usage is tracked on social media through ElonJet. In December 2022, Musk banned the ElonJet account on Twitter, and made temporary bans on the accounts of journalists that posted stories regarding the incident, including Donie O'Sullivan, Keith Olbermann, and journalists from The New York Times, The Washington Post, CNN, and The Intercept. In October 2025, Musk's company xAI launched Grokipedia, an AI-generated online encyclopedia that he promoted as an alternative to Wikipedia. Articles on Grokipedia are generated and reviewed by xAI's Grok chatbot. Media coverage and academic analysis described Grokipedia as frequently reusing Wikipedia content but framing contested political and social topics in line with Musk's own views and right-wing narratives. A study by Cornell University researchers and NBC News stated that Grokipedia cites sources that are blacklisted or considered "generally unreliable" on Wikipedia, for example, the conspiracy site Infowars and the neo-Nazi forum Stormfront. Wired, The Guardian and Time criticized Grokipedia for factual errors and for presenting Musk himself in unusually positive terms while downplaying controversies. Politics Musk is an outlier among business leaders who typically avoid partisan political advocacy. Musk was a registered independent voter when he lived in California. Historically, he has donated to both Democrats and Republicans, many of whom serve in states in which he has a vested interest. Since 2022, his political contributions have mostly supported Republicans, with his first vote for a Republican going to Mayra Flores in the 2022 Texas's 34th congressional district special election. In 2024, he started supporting international far-right political parties, activists, and causes, and has shared misinformation and numerous conspiracy theories. Since 2024, his views have been generally described as right-wing. Musk supported Barack Obama in 2008 and 2012, Hillary Clinton in 2016, Joe Biden in 2020, and Donald Trump in 2024. In the 2020 Democratic Party presidential primaries, Musk endorsed candidate Andrew Yang and expressed support for Yang's proposed universal basic income, and endorsed Kanye West's 2020 presidential campaign. In 2021, Musk publicly expressed opposition to the Build Back Better Act, a $3.5 trillion legislative package endorsed by Joe Biden that ultimately failed to pass due to unanimous opposition from congressional Republicans and several Democrats. In 2022, gave over $50 million to Citizens for Sanity, a conservative political action committee. In 2023, he supported Republican Ron DeSantis for the 2024 U.S. presidential election, giving $10 million to his campaign, and hosted DeSantis's campaign announcement on a Twitter Spaces event. From June 2023 to January 2024, Musk hosted a bipartisan set of X Spaces with Republican and Democratic candidates, including Robert F. Kennedy Jr., Vivek Ramaswamy, and Dean Phillips. In October 2025, former vice-president Kamala Harris commented that it was a mistake from the Democratic side to not invite Musk to a White House electric vehicle event organized in August 2021 and featuring executives from General Motors, Ford and Stellantis, despite Tesla being "the major American manufacturer of extraordinary innovation in this space." Fortune remarked that this was a nod to United Auto Workers and organized labor. Harris said presidents should put aside political loyalties when it came to recognizing innovation, and guessed that the non-invitation impacted Musk's perspective. Fortune noted that, at the time, Musk said, "Yeah, seems odd that Tesla wasn't invited." A month later, he criticized Biden as "not the friendliest administration." Jacob Silverman, author of the book Gilded Rage: Elon Musk and the Radicalization of Silicon Valley, said that the tech industry represented by Musk, Thiel, Andreessen and other capitalists, actually flourished under Biden, but the tech leaders chose Trump for their common ground on cultural issues. By early 2024, Musk had become a vocal and financial supporter of Donald Trump. In July 2024, minutes after the attempted assassination of Donald Trump, Musk endorsed him for president saying; "I fully endorse President Trump and hope for his rapid recovery." During the presidential campaign, Musk joined Trump on stage at a campaign rally, and during the campaign promoted conspiracy theories and falsehoods about Democrats, election fraud and immigration, in support of Trump. Musk was the largest individual donor of the 2024 election. In 2025, Musk contributed $19 million to the Wisconsin Supreme Court race, hoping to influence the state's future redistricting efforts and its regulations governing car manufacturers and dealers. In 2023, Musk said he shunned the World Economic Forum because it was boring. The organization commented that they had not invited him since 2015. He has participated in Dialog, dubbed "Tech Bilderberg" and organized by Peter Thiel and Auren Hoffman, though. Musk's international political actions and comments have come under increasing scrutiny and criticism, especially from the governments and leaders of France, Germany, Norway, Spain and the United Kingdom, particularly due to his position in the U.S. government as well as ownership of X. An NBC News analysis found he had boosted far-right political movements to cut immigration and curtail regulation of business in at least 18 countries on six continents since 2023. During his speech after the second inauguration of Donald Trump, Musk twice made a gesture interpreted by many as a Nazi or a fascist Roman salute.[e] He thumped his right hand over his heart, fingers spread wide, and then extended his right arm out, emphatically, at an upward angle, palm down and fingers together. He then repeated the gesture to the crowd behind him. As he finished the gestures, he said to the crowd, "My heart goes out to you. It is thanks to you that the future of civilization is assured." It was widely condemned as an intentional Nazi salute in Germany, where making such gestures is illegal. The Anti-Defamation League said it was not a Nazi salute, but other Jewish organizations disagreed and condemned the salute. American public opinion was divided on partisan lines as to whether it was a fascist salute. Musk dismissed the accusations of Nazi sympathies, deriding them as "dirty tricks" and a "tired" attack. Neo-Nazi and white supremacist groups celebrated it as a Nazi salute. Multiple European political parties demanded that Musk be banned from entering their countries. The concept of DOGE emerged in a discussion between Musk and Donald Trump, and in August 2024, Trump committed to giving Musk an advisory role, with Musk accepting the offer. In November and December 2024, Musk suggested that the organization could help to cut the U.S. federal budget, consolidate the number of federal agencies, and eliminate the Consumer Financial Protection Bureau, and that its final stage would be "deleting itself". In January 2025, the organization was created by executive order, and Musk was designated a "special government employee". Musk led the organization and was a senior advisor to the president, although his official role is not clear. In sworn statement during a lawsuit, the director of the White House Office of Administration stated that Musk "is not an employee of the U.S. DOGE Service or U.S. DOGE Service Temporary Organization", "is not the U.S. DOGE Service administrator", and has "no actual or formal authority to make government decisions himself". Trump said two days later that he had put Musk in charge of DOGE. A federal judge has ruled that Musk acted as the de facto leader of DOGE. Musk's role in the second Trump administration, particularly in response to DOGE, has attracted public backlash. He was criticized for his treatment of federal government employees, including his influence over the mass layoffs of the federal workforce. He has prioritized secrecy within the organization and has accused others of violating privacy laws. A Senate report alleged that Musk could avoid up to $2 billion in legal liability as a result of DOGE's actions. In May 2025, Bill Gates accused Musk of "killing the world's poorest children" through his cuts to USAID, which modeling by Boston University estimated had resulted in 300,000 deaths by this time, most of them of children. By November 2025, the estimated death toll had increased to 400,000 children and 200,000 adults. Musk announced on May 28, 2025, that he would depart from the Trump administration as planned when the special government employee's 130 day deadline expired, with a White House official confirming that Musk's offboarding from the Trump administration was already underway. His departure was officially confirmed during a joint Oval Office press conference with Trump on May 30, 2025. @realDonaldTrump is in the Epstein files. That is the real reason they have not been made public. June 5, 2025 After leaving office, Musk criticized the Trump administration's Big Beautiful Bill, calling it a "disgusting abomination" due to its provisions increasing the deficit. A feud began between Musk and Trump, with its most notable event being Musk alleging Trump had ties to sex offender Jeffrey Epstein on X (formerly Twitter) on June 5, 2025. Trump responded on Truth Social stating that Musk went "CRAZY" after the "EV Mandate" was purportedly taken away and threatened to cut Musk's government contracts. Musk then called for a third Trump impeachment. The next day, Trump stated that he did not wish to reconcile with Musk, and added that Musk would face "very serious consequences" if he funds Democratic candidates. On June 11, Musk publicly apologized for the tweets against Trump, saying they "went too far". Views November 6, 2022 Rejecting the conservative label, Musk has described himself as a political moderate, even as his views have become more right-wing over time. His views have been characterized as libertarian and far-right, and after his involvement in European politics, they have received criticism from world leaders such as Emmanuel Macron and Olaf Scholz. Within the context of American politics, Musk supported Democratic candidates up until 2022, at which point he voted for a Republican for the first time. He has stated support for universal basic income, gun rights, freedom of speech, a tax on carbon emissions, and H-1B visas. Musk has expressed concern about issues such as artificial intelligence (AI) and climate change, and has been a critic of wealth tax, short-selling, and government subsidies. An immigrant himself, Musk has been accused of being anti-immigration, and regularly blames immigration policies for illegal immigration. He is also a pronatalist who believes population decline is the biggest threat to civilization, and identifies as a cultural Christian. Musk has long been an advocate for space colonization, especially the colonization of Mars. He has repeatedly pushed for humanity colonizing Mars, in order to become an interplanetary species and lower the risks of human extinction. Musk has promoted conspiracy theories and made controversial statements that have led to accusations of racism, sexism, antisemitism, transphobia, disseminating disinformation, and support of white pride. While describing himself as a "pro-Semite", his comments regarding George Soros and Jewish communities have been condemned by the Anti-Defamation League and the Biden White House. Musk was criticized during the COVID-19 pandemic for making unfounded epidemiological claims, defying COVID-19 lockdowns restrictions, and supporting the Canada convoy protest against vaccine mandates. He has amplified false claims of white genocide in South Africa. Musk has been critical of Israel's actions in the Gaza Strip during the Gaza war, praised China's economic and climate goals, suggested that Taiwan and China should resolve cross-strait relations, and was described as having a close relationship with the Chinese government. In Europe, Musk expressed support for Ukraine in 2022 during the Russian invasion, recommended referendums and peace deals on the annexed Russia-occupied territories, and supported the far-right Alternative for Germany political party in 2024. Regarding British politics, Musk blamed the 2024 UK riots on mass migration and open borders, criticized Prime Minister Keir Starmer for what he described as a "two-tier" policing system, and was subsequently attacked as being responsible for spreading misinformation and amplifying the far-right. He has also voiced his support for far-right activist Tommy Robinson and pledged electoral support for Reform UK. In February 2026, Musk described Spanish Prime Minister Pedro Sánchez as a "tyrant" following Sánchez's proposal to prohibit minors under the age of 16 from accessing social media platforms. Legal affairs In 2018, Musk was sued by the U.S. Securities and Exchange Commission (SEC) for a tweet stating that funding had been secured for potentially taking Tesla private.[f] The securities fraud lawsuit characterized the tweet as false, misleading, and damaging to investors, and sought to bar Musk from serving as CEO of publicly traded companies. Two days later, Musk settled with the SEC, without admitting or denying the SEC's allegations. As a result, Musk and Tesla were fined $20 million each, and Musk was forced to step down for three years as Tesla chairman but was able to remain as CEO. Shareholders filed a lawsuit over the tweet, and in February 2023, a jury found Musk and Tesla not liable. Musk has stated in interviews that he does not regret posting the tweet that triggered the SEC investigation. In 2019, Musk stated in a tweet that Tesla would build half a million cars that year. The SEC reacted by asking a court to hold him in contempt for violating the terms of the 2018 settlement agreement. A joint agreement between Musk and the SEC eventually clarified the previous agreement details, including a list of topics about which Musk needed preclearance. In 2020, a judge blocked a lawsuit that claimed a tweet by Musk regarding Tesla stock price ("too high imo") violated the agreement. Freedom of Information Act (FOIA)-released records showed that the SEC concluded Musk had subsequently violated the agreement twice by tweeting regarding "Tesla's solar roof production volumes and its stock price". In October 2023, the SEC sued Musk over his refusal to testify a third time in an investigation into whether he violated federal law by purchasing Twitter stock in 2022. In February 2024, Judge Laurel Beeler ruled that Musk must testify again. In January 2025, the SEC filed a lawsuit against Musk for securities violations related to his purchase of Twitter. In January 2024, Delaware judge Kathaleen McCormick ruled in a 2018 lawsuit that Musk's $55 billion pay package from Tesla be rescinded. McCormick called the compensation granted by the company's board "an unfathomable sum" that was unfair to shareholders. The Delaware Supreme Court overturned McCormick's decision in December 2025, restoring Musk's compensation package and awarding $1 in nominal damages. Personal life Musk became a U.S. citizen in 2002. From the early 2000s until late 2020, Musk resided in California, where both Tesla and SpaceX were founded. He then relocated to Cameron County, Texas, saying that California had become "complacent" about its economic success. While hosting Saturday Night Live in 2021, Musk stated that he has Asperger syndrome (an outdated term for autism spectrum disorder). When asked about his experience growing up with Asperger's syndrome in a TED2022 conference in Vancouver, Musk stated that "the social cues were not intuitive ... I would just tend to take things very literally ... but then that turned out to be wrong — [people were not] simply saying exactly what they mean, there's all sorts of other things that are meant, and [it] took me a while to figure that out." Musk suffers from back pain and has undergone several spine-related surgeries, including a disc replacement. In 2000, he contracted a severe case of malaria while on vacation in South Africa. Musk has stated he uses doctor-prescribed ketamine for occasional depression and that he doses "a small amount once every other week or something like that"; since January 2024, some media outlets have reported that he takes ketamine, marijuana, LSD, ecstasy, mushrooms, cocaine and other drugs. Musk at first refused to comment on his alleged drug use, before responding that he had not tested positive for drugs, and that if drugs somehow improved his productivity, "I would definitely take them!". The New York Times' investigations revealed Musk's overuse of ketamine and numerous other drugs, as well as strained family relationships and concerns from close associates who have become troubled by his public behavior as he became more involved in political activities and government work. According to The Washington Post, President Trump described Musk as "a big-time drug addict". Through his own label Emo G Records, Musk released a rap track, "RIP Harambe", on SoundCloud in March 2019. The following year, he released an EDM track, "Don't Doubt Ur Vibe", featuring his own lyrics and vocals. Musk plays video games, which he stated has a "'restoring effect' that helps his 'mental calibration'". Some games he plays include Quake, Diablo IV, Elden Ring, and Polytopia. Musk once claimed to be one of the world's top video game players but has since admitted to "account boosting", or cheating by hiring outside services to achieve top player rankings. Musk has justified the boosting by claiming that all top accounts do it so he has to as well to remain competitive. In 2024 and 2025, Musk criticized the video game Assassin's Creed Shadows and its creator Ubisoft for "woke" content. Musk posted to X that "DEI kills art" and specified the inclusion of the historical figure Yasuke in the Assassin's Creed game as offensive; he also called the game "terrible". Ubisoft responded by saying that Musk's comments were "just feeding hatred" and that they were focused on producing a game not pushing politics. Musk has fathered at least 14 children, one of whom died as an infant. The Wall Street Journal reported in 2025 that sources close to Musk suggest that the "true number of Musk's children is much higher than publicly known". He had six children with his first wife, Canadian author Justine Wilson, whom he met while attending Queen's University in Ontario, Canada; they married in 2000. In 2002, their first child Nevada Musk died of sudden infant death syndrome at the age of 10 weeks. After his death, the couple used in vitro fertilization (IVF) to continue their family; they had twins in 2004, followed by triplets in 2006. The couple divorced in 2008 and have shared custody of their children. The elder twin he had with Wilson came out as a trans woman and, in 2022, officially changed her name to Vivian Jenna Wilson, adopting her mother's surname because she no longer wished to be associated with Musk. Musk began dating English actress Talulah Riley in 2008. They married two years later at Dornoch Cathedral in Scotland. In 2012, the couple divorced, then remarried the following year. After briefly filing for divorce in 2014, Musk finalized a second divorce from Riley in 2016. Musk then dated the American actress Amber Heard for several months in 2017; he had reportedly been "pursuing" her since 2012. In 2018, Musk and Canadian musician Grimes confirmed they were dating. Grimes and Musk have three children, born in 2020, 2021, and 2022.[g] Musk and Grimes originally gave their eldest child the name "X Æ A-12", which would have violated California regulations as it contained characters that are not in the modern English alphabet; the names registered on the birth certificate are "X" as a first name, "Æ A-Xii" as a middle name, and "Musk" as a last name. They received criticism for choosing a name perceived to be impractical and difficult to pronounce; Musk has said the intended pronunciation is "X Ash A Twelve". Their second child was born via surrogacy. Despite the pregnancy, Musk confirmed reports that the couple were "semi-separated" in September 2021; in an interview with Time in December 2021, he said he was single. In October 2023, Grimes sued Musk over parental rights and custody of X Æ A-Xii. Elon Musk has taken X Æ A-Xii to multiple official events in Washington, D.C. during Trump's second term in office. Also in July 2022, The Wall Street Journal reported that Musk allegedly had an affair with Nicole Shanahan, the wife of Google co-founder Sergey Brin, in 2021, leading to their divorce the following year. Musk denied the report. Musk also had a relationship with Australian actress Natasha Bassett, who has been described as "an occasional girlfriend". In October 2024, The New York Times reported Musk bought a Texas compound for his children and their mothers, though Musk denied having done so. Musk also has four children with Shivon Zilis, director of operations and special projects at Neuralink: twins born via IVF in 2021, a child born in 2024 via surrogacy and a child born in 2025.[h] On February 14, 2025, Ashley St. Clair, an influencer and author, posted on X claiming to have given birth to Musk's son Romulus five months earlier, which media outlets reported as Musk's supposed thirteenth child.[i] On February 22, 2025, it was reported that St Clair had filed for sole custody of her five-month-old son and for Musk to be recognised as the child's father. On March 31, 2025, Musk wrote that, while he was unsure if he was the father of St. Clair's child, he had paid St. Clair $2.5 million and would continue paying her $500,000 per year.[j] Later reporting from the Wall Street Journal indicated that $1 million of these payments to St. Clair were structured as a loan. In 2014, Musk and Ghislaine Maxwell appeared together in a photograph taken at an Academy Awards after-party, which Musk later described as a "photobomb". The January 2026 Epstein files contain emails between Musk and Epstein from 2012 to 2013, after Epstein's first conviction. Emails released on January 30, 2026, indicated that Epstein invited Musk to visit his private island on multiple occasions. The correspondence showed that while Epstein repeatedly encouraged Musk to attend, Musk did not visit the island. In one instance, Musk discussed the possibility of attending a party with his then-wife Talulah Riley and asked which day would be the "wildest party"; according to the emails, the visit did not take place after Epstein later cancelled the plans.[k] On Christmas day in 2012, Musk emailed Epstein asking "Do you have any parties planned? I’ve been working to the edge of sanity this year and so, once my kids head home after Christmas, I really want to hit the party scene in St Barts or elsewhere and let loose. The invitation is much appreciated, but a peaceful island experience is the opposite of what I’m looking for". Epstein replied that the "ratio on my island" might make Musk's wife uncomfortable to which Musk responded, "Ratio is not a problem for Talulah". On September 11, 2013, Epstein sent an email asking Musk if he had any plans for coming to New York for the opening of the United Nations General Assembly where many "interesting people" would be coming to his house to which Musk responded that "Flying to NY to see UN diplomats do nothing would be an unwise use of time". Epstein responded by stating "Do you think i am retarded. Just kidding, there is no one over 25 and all very cute." Musk has denied any close relationship with Epstein and described him as a "creep" who attempted to ingratiate himself with influential people. When Musk was asked in 2019 if he introduced Epstein to Mark Zuckerberg, Musk responded: "I don’t recall introducing Epstein to anyone, as I don’t know the guy well enough to do so." The released emails nonetheless showed cordial exchanges on a range of topics, including Musk's inquiry about parties on the island. The correspondence also indicated that Musk suggested hosting Epstein at SpaceX, while Epstein separately discussed plans to tour SpaceX and bring "the girls", though there is no evidence that such a visit occurred. Musk has described the release of the files a "distraction", later accusing the second Trump administration of suppressing them to protect powerful individuals, including Trump himself.[l] Wealth Elon Musk is the wealthiest person in the world, with an estimated net worth of US$690 billion as of January 2026, according to the Bloomberg Billionaires Index, and $852 billion according to Forbes, primarily from his ownership stakes in SpaceX and Tesla. Having been first listed on the Forbes Billionaires List in 2012, around 75% of Musk's wealth was derived from Tesla stock in November 2020, although he describes himself as "cash poor". According to Forbes, he became the first person in the world to achieve a net worth of $300 billion in 2021; $400 billion in December 2024; $500 billion in October 2025; $600 billion in mid-December 2025; $700 billion later that month; and $800 billion in February 2026. In November 2025, a Tesla pay package worth potentially $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Public image Although his ventures have been highly influential within their separate industries starting in the 2000s, Musk only became a public figure in the early 2010s. He has been described as an eccentric who makes spontaneous and impactful decisions, while also often making controversial statements, contrary to other billionaires who prefer reclusiveness to protect their businesses. Musk's actions and his expressed views have made him a polarizing figure. Biographer Ashlee Vance described people's opinions of Musk as polarized due to his "part philosopher, part troll" persona on Twitter. He has drawn denouncement for using his platform to mock the self-selection of personal pronouns, while also receiving praise for bringing international attention to matters like British survivors of grooming gangs. Musk has been described as an American oligarch due to his extensive influence over public discourse, social media, industry, politics, and government policy. After Trump's re-election, Musk's influence and actions during the transition period and the second presidency of Donald Trump led some to call him "President Musk", the "actual president-elect", "shadow president" or "co-president". Awards for his contributions to the development of the Falcon rockets include the American Institute of Aeronautics and Astronautics George Low Transportation Award in 2008, the Fédération Aéronautique Internationale Gold Space Medal in 2010, and the Royal Aeronautical Society Gold Medal in 2012. In 2015, he received an honorary doctorate in engineering and technology from Yale University and an Institute of Electrical and Electronics Engineers Honorary Membership. Musk was elected a Fellow of the Royal Society (FRS) in 2018.[m] In 2022, Musk was elected to the National Academy of Engineering. Time has listed Musk as one of the most influential people in the world in 2010, 2013, 2018, and 2021. Musk was selected as Time's "Person of the Year" for 2021. Then Time editor-in-chief Edward Felsenthal wrote that, "Person of the Year is a marker of influence, and few individuals have had more influence than Musk on life on Earth, and potentially life off Earth too." Notes References Works cited Further reading External links |
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Contents CSIRAC CSIRAC (/ˈsaɪræk/; Commonwealth Scientific and Industrial Research Automatic Computer), originally known as CSIR Mk 1, was Australia's first digital computer, and the fifth stored-program computer in the world. It is the oldest surviving first-generation electronic computer (the Zuse Z4 at the Deutsches Museum is older, but was electro-mechanical, not electronic). It was the first computer to play digital music. After it was retired, it was exhibited at Melbourne Museum for many years. Later it was relocated to Scienceworks in 2018 and is now on permanent display in the Think Ahead gallery. A comprehensive source of information about the CSIRA collection, its contributors and related topics is available from Museums Victoria on their Collections website. History The CSIRAC was constructed by a team led by Trevor Pearcey and Maston Beard, working in large part independently of similar efforts across Europe and the United States, and ran its first test program (multiplication of numbers) sometime in November 1949. It started restricted operation in late 1950 and was publicly demonstrated and operational in 1951. Design The machine was fairly representative of first-generation valve-driven computer designs. It used mercury acoustic delay lines as its primary data storage, with a typical capacity of 768 20-bit words, supplemented by a parallel disk-type device with a total 4096-word capacity and an access time of 10 milliseconds. Its memory clock ran at 1000 Hz, and the control unit, synchronized to the clock, took two cycles to execute an instruction (later the speed was doubled to one cycle per instruction). The bus (termed the "digit trunk" in their design) is unusual compared to most computers in that it was serial—it transferred one bit at a time. Most of CSIRAC's approximately 2000 valves were of the types 6SN7, 6V6, EA50 diodes and KT66. George Semkiw later redesigned the drum-read electronics to use germanium transistors.[citation needed] Input to the machine was performed in the form of punched 3-inch (76 mm) wide, 12-track paper tape, after experiments with punch cards proved unsatisfactory. The machine was controlled through a console which allowed programs to be stepped through one instruction at a time, and featured CRT displays which showed the contents of registers. Output was through a standard teleprinter or to punch tape.[citation needed] The instruction set supported the basic set of arithmetic and logical operations, as well as conditional and relative jumps (making it possible to write a library of subroutines). Instructions consisted of three components: a 5-bit "destination" P1-P5, a 5-bit "source" P6-P10, and a 10-bit "address" P11-P20. For instructions that used the main store, the six bits P15-P20 selected one of the 64 logical delay lines. Bits P11-P14 determined the time at which 20 bits of data were written to or extracted from the delay line, and thus represented address of a word within the selected delay line. There were 32 destination gates and 32 source gates; the 10 address bits identified a data word within the store if either the source or destination required access to the store. The total number of source and destination combinations, or different instruction functions, was 1024, although only about 256 of these were used often. The machine had three 20-bit registers (A, B and C), two of which were involved in multiplication, one 10-bit register which could link to either half of a word, and a group of 16 20-bit registers, addressed via bits P11-P14. In addition the 20-bit program counter (S register), and the instruction register (K) were accessible.[citation needed] The machine, like all machines of the era, had no operating system. A high-level interpreted programming language called INTERPROGRAM was developed in 1960 by Geoff Hill. It was similar to early forms of BASIC, which was designed in 1963 for the 20-bit transistorized GE-200 series. In 1950 CSIRAC was used to play music, the first known use of a digital computer for the purpose. The music was never recorded, but it has been accurately reconstructed. In 1955, with the CSIRO's decision that computing research was outside its purview, the machine was transferred from its home at the Radiophysics Laboratory at the CSIRO in Sydney, to the University of Melbourne, where it formed Australia's only academic computing facility until late 1956. Many pioneers of computer use in Australia[who?] had their first exposure to computing there.[citation needed] Preservation In 1964, CSIRAC was shut down for the last time. Its historical significance was already recognised at that stage, and it was placed in storage with plans for its later exhibition in a museum. The machine was stored in a warehouse through the 1960s and 1970s, before being set up for exhibit at Caulfield Institute of Technology (later the Caulfield Campus of Chisholm Institute of Technology, and later again the Caulfield Campus of Monash University) from 1980 to 1992. It was then returned to storage.[citation needed] Interest in the machine was revived in the 1990s, as it was realised that many of its developers were ageing and history was being lost forever. A conference about the machine was held in 1996. The machine found a permanent home with Museums Victoria in 2000. It has not been operable since its shutdown, but many of the programs that ran on it have been preserved, and an emulator has been written for it. The curators have decided that, aside from the cost of restoring the device, the huge number of repairs that would be required to make it safe to operate (CSIRAC used 30 kilowatts of power in operation) would detract from its historical authenticity. After being exhibited at Melbourne Museum for many years, it was relocated to Scienceworks in 2018 and is now on permanent display in the Think Ahead gallery. CSIRAC is listed on the Victorian Heritage Register and is included in a Heritage Overlay. It is listed as a National Engineering Landmark by Engineers Australia as part of its Engineering Heritage Recognition Program. Legacy In 2025, Australian electronic DJ and music producer Ninajirachi released the song "CSIRAC", paying tribute to the computer, on her debut album I Love My Computer. See also References External links |
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Contents Transaction Application Language Transaction Application Language or TAL (originally "Tandem Application Language") is a block-structured, procedural language optimized for use on Tandem (and later HP NonStop) hardware. TAL resembles a cross between C and Pascal. It was the original system programming language for the Tandem Computers CISC machines, which had no assembler. The design concept of TAL, an evolution of Hewlett-Packard's SPL, was intimately associated and optimized with a microprogrammed CISC instruction set. Each TAL statement could easily compile into a sequence of instructions that manipulated data on a transient floating register stack. The register stack itself floated at the crest of the program's memory allocation and call stack. The language itself has the appearance of ALGOL or Pascal, with BEGIN and END statements. However, its semantics are far more like C. It does not permit indefinite levels of procedure nesting, it does not pass complex structured arguments by value, and it does not strictly type most variable references. Programming techniques are much like C using pointers to structures, occasional overlays, deliberate string handling and casts when appropriate. Available datatypes include 8-bit, 16-bit, 32-bit and (introduced later) 64-bit integers. Microcode level support was available for null terminated character strings. However, this is not commonly used. Originally the Tandem NonStop operating system was written in TAL. Much of it has since been rewritten in C and TAL has been deprecated for new development. In the migration from CISC to RISC, TAL was updated/replaced with pTAL – compilers allowed TAL to be re-compiled into Native RISC Applications. Later, the epTAL compiler was introduced for Itanium processors. See also References Further reading |
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[SOURCE: https://en.wikipedia.org/wiki/OpenAI#cite_note-227] | [TOKENS: 8773] |
Contents OpenAI OpenAI is an American artificial intelligence research organization comprising both a non-profit foundation and a controlled for-profit public benefit corporation (PBC), headquartered in San Francisco. It aims to develop "safe and beneficial" artificial general intelligence (AGI), which it defines as "highly autonomous systems that outperform humans at most economically valuable work". OpenAI is widely recognized for its development of the GPT family of large language models, the DALL-E series of text-to-image models, and the Sora series of text-to-video models, which have influenced industry research and commercial applications. Its release of ChatGPT in November 2022 has been credited with catalyzing widespread interest in generative AI. The organization was founded in 2015 in Delaware but evolved a complex corporate structure. As of October 2025, following restructuring approved by California and Delaware regulators, the non-profit OpenAI Foundation holds 26% of the for-profit OpenAI Group PBC, with Microsoft holding 27% and employees/other investors holding 47%. Under its governance arrangements, the OpenAI Foundation holds the authority to appoint the board of the for-profit OpenAI Group PBC, a mechanism designed to align the entity’s strategic direction with the Foundation’s charter. Microsoft previously invested over $13 billion into OpenAI, and provides Azure cloud computing resources. In October 2025, OpenAI conducted a $6.6 billion share sale that valued the company at $500 billion. In 2023 and 2024, OpenAI faced multiple lawsuits for alleged copyright infringement against authors and media companies whose work was used to train some of OpenAI's products. In November 2023, OpenAI's board removed Sam Altman as CEO, citing a lack of confidence in him, but reinstated him five days later following a reconstruction of the board. Throughout 2024, roughly half of then-employed AI safety researchers left OpenAI, citing the company's prominent role in an industry-wide problem. Founding In December 2015, OpenAI was founded as a not for profit organization by Sam Altman, Elon Musk, Ilya Sutskever, Greg Brockman, Trevor Blackwell, Vicki Cheung, Andrej Karpathy, Durk Kingma, John Schulman, Pamela Vagata, and Wojciech Zaremba, with Sam Altman and Elon Musk as the co-chairs. A total of $1 billion in capital was pledged by Sam Altman, Greg Brockman, Elon Musk, Reid Hoffman, Jessica Livingston, Peter Thiel, Amazon Web Services (AWS), and Infosys. However, the actual capital collected significantly lagged pledges. According to company disclosures, only $130 million had been received by 2019. In its founding charter, OpenAI stated an intention to collaborate openly with other institutions by making certain patents and research publicly available, but later restricted access to its most capable models, citing competitive and safety concerns. OpenAI was initially run from Brockman's living room. It was later headquartered at the Pioneer Building in the Mission District, San Francisco. According to OpenAI's charter, its founding mission is "to ensure that artificial general intelligence (AGI)—by which we mean highly autonomous systems that outperform humans at most economically valuable work—benefits all of humanity." Musk and Altman stated in 2015 that they were partly motivated by concerns about AI safety and existential risk from artificial general intelligence. OpenAI stated that "it's hard to fathom how much human-level AI could benefit society", and that it is equally difficult to comprehend "how much it could damage society if built or used incorrectly". The startup also wrote that AI "should be an extension of individual human wills and, in the spirit of liberty, as broadly and evenly distributed as possible", and that "because of AI's surprising history, it's hard to predict when human-level AI might come within reach. When it does, it'll be important to have a leading research institution which can prioritize a good outcome for all over its own self-interest." Co-chair Sam Altman expected a decades-long project that eventually surpasses human intelligence. Brockman met with Yoshua Bengio, one of the "founding fathers" of deep learning, and drew up a list of great AI researchers. Brockman was able to hire nine of them as the first employees in December 2015. OpenAI did not pay AI researchers salaries comparable to those of Facebook or Google. It also did not pay stock options which AI researchers typically get. Nevertheless, OpenAI spent $7 million on its first 52 employees in 2016. OpenAI's potential and mission drew these researchers to the firm; a Google employee said he was willing to leave Google for OpenAI "partly because of the very strong group of people and, to a very large extent, because of its mission." OpenAI co-founder Wojciech Zaremba stated that he turned down "borderline crazy" offers of two to three times his market value to join OpenAI instead. In April 2016, OpenAI released a public beta of "OpenAI Gym", its platform for reinforcement learning research. Nvidia gifted its first DGX-1 supercomputer to OpenAI in August 2016 to help it train larger and more complex AI models with the capability of reducing processing time from six days to two hours. In December 2016, OpenAI released "Universe", a software platform for measuring and training an AI's general intelligence across the world's supply of games, websites, and other applications. Corporate structure In 2019, OpenAI transitioned from non-profit to "capped" for-profit, with the profit being capped at 100 times any investment. According to OpenAI, the capped-profit model allows OpenAI Global, LLC to legally attract investment from venture funds and, in addition, to grant employees stakes in the company. Many top researchers work for Google Brain, DeepMind, or Facebook, which offer equity that a nonprofit would be unable to match. Before the transition, OpenAI was legally required to publicly disclose the compensation of its top employees. The company then distributed equity to its employees and partnered with Microsoft, announcing an investment package of $1 billion into the company. Since then, OpenAI systems have run on an Azure-based supercomputing platform from Microsoft. OpenAI Global, LLC then announced its intention to commercially license its technologies. It planned to spend $1 billion "within five years, and possibly much faster". Altman stated that even a billion dollars may turn out to be insufficient, and that the lab may ultimately need "more capital than any non-profit has ever raised" to achieve artificial general intelligence. The nonprofit, OpenAI, Inc., is the sole controlling shareholder of OpenAI Global, LLC, which, despite being a for-profit company, retains a formal fiduciary responsibility to OpenAI, Inc.'s nonprofit charter. A majority of OpenAI, Inc.'s board is barred from having financial stakes in OpenAI Global, LLC. In addition, minority members with a stake in OpenAI Global, LLC are barred from certain votes due to conflict of interest. Some researchers have argued that OpenAI Global, LLC's switch to for-profit status is inconsistent with OpenAI's claims to be "democratizing" AI. On February 29, 2024, Elon Musk filed a lawsuit against OpenAI and CEO Sam Altman, accusing them of shifting focus from public benefit to profit maximization—a case OpenAI dismissed as "incoherent" and "frivolous," though Musk later revived legal action against Altman and others in August. On April 9, 2024, OpenAI countersued Musk in federal court, alleging that he had engaged in "bad-faith tactics" to slow the company's progress and seize its innovations for his personal benefit. OpenAI also argued that Musk had previously supported the creation of a for-profit structure and had expressed interest in controlling OpenAI himself. The countersuit seeks damages and legal measures to prevent further alleged interference. On February 10, 2025, a consortium of investors led by Elon Musk submitted a $97.4 billion unsolicited bid to buy the nonprofit that controls OpenAI, declaring willingness to match or exceed any better offer. The offer was rejected on 14 February 2025, with OpenAI stating that it was not for sale, but the offer complicated Altman's restructuring plan by suggesting a lower bar for how much the nonprofit should be valued. OpenAI, Inc. was originally designed as a nonprofit in order to ensure that AGI "benefits all of humanity" rather than "the private gain of any person". In 2019, it created OpenAI Global, LLC, a capped-profit subsidiary controlled by the nonprofit. In December 2024, OpenAI proposed a restructuring plan to convert the capped-profit into a Delaware-based public benefit corporation (PBC), and to release it from the control of the nonprofit. The nonprofit would sell its control and other assets, getting equity in return, and would use it to fund and pursue separate charitable projects, including in science and education. OpenAI's leadership described the change as necessary to secure additional investments, and claimed that the nonprofit's founding mission to ensure AGI "benefits all of humanity" would be better fulfilled. The plan has been criticized by former employees. A legal letter named "Not For Private Gain" asked the attorneys general of California and Delaware to intervene, stating that the restructuring is illegal and would remove governance safeguards from the nonprofit and the attorneys general. The letter argues that OpenAI's complex structure was deliberately designed to remain accountable to its mission, without the conflicting pressure of maximizing profits. It contends that the nonprofit is best positioned to advance its mission of ensuring AGI benefits all of humanity by continuing to control OpenAI Global, LLC, whatever the amount of equity that it could get in exchange. PBCs can choose how they balance their mission with profit-making. Controlling shareholders have a large influence on how closely a PBC sticks to its mission. On October 28, 2025, OpenAI announced that it had adopted the new PBC corporate structure after receiving approval from the attorneys general of California and Delaware. Under the new structure, OpenAI's for-profit branch became a public benefit corporation known as OpenAI Group PBC, while the non-profit was renamed to the OpenAI Foundation. The OpenAI Foundation holds a 26% stake in the PBC, while Microsoft holds a 27% stake and the remaining 47% is owned by employees and other investors. All members of the OpenAI Group PBC board of directors will be appointed by the OpenAI Foundation, which can remove them at any time. Members of the Foundation's board will also serve on the for-profit board. The new structure allows the for-profit PBC to raise investor funds like most traditional tech companies, including through an initial public offering, which Altman claimed was the most likely path forward. In January 2023, OpenAI Global, LLC was in talks for funding that would value the company at $29 billion, double its 2021 value. On January 23, 2023, Microsoft announced a new US$10 billion investment in OpenAI Global, LLC over multiple years, partially needed to use Microsoft's cloud-computing service Azure. From September to December, 2023, Microsoft rebranded all variants of its Copilot to Microsoft Copilot, and they added MS-Copilot to many installations of Windows and released Microsoft Copilot mobile apps. Following OpenAI's 2025 restructuring, Microsoft owns a 27% stake in the for-profit OpenAI Group PBC, valued at $135 billion. In a deal announced the same day, OpenAI agreed to purchase $250 billion of Azure services, with Microsoft ceding their right of first refusal over OpenAI's future cloud computing purchases. As part of the deal, OpenAI will continue to share 20% of its revenue with Microsoft until it achieves AGI, which must now be verified by an independent panel of experts. The deal also loosened restrictions on both companies working with third parties, allowing Microsoft to pursue AGI independently and allowing OpenAI to develop products with other companies. In 2017, OpenAI spent $7.9 million, a quarter of its functional expenses, on cloud computing alone. In comparison, DeepMind's total expenses in 2017 were $442 million. In the summer of 2018, training OpenAI's Dota 2 bots required renting 128,000 CPUs and 256 GPUs from Google for multiple weeks. In October 2024, OpenAI completed a $6.6 billion capital raise with a $157 billion valuation including investments from Microsoft, Nvidia, and SoftBank. On January 21, 2025, Donald Trump announced The Stargate Project, a joint venture between OpenAI, Oracle, SoftBank and MGX to build an AI infrastructure system in conjunction with the US government. The project takes its name from OpenAI's existing "Stargate" supercomputer project and is estimated to cost $500 billion. The partners planned to fund the project over the next four years. In July, the United States Department of Defense announced that OpenAI had received a $200 million contract for AI in the military, along with Anthropic, Google, and xAI. In the same month, the company made a deal with the UK Government to use ChatGPT and other AI tools in public services. OpenAI subsequently began a $50 million fund to support nonprofit and community organizations. In April 2025, OpenAI raised $40 billion at a $300 billion post-money valuation, which was the highest-value private technology deal in history. The financing round was led by SoftBank, with other participants including Microsoft, Coatue, Altimeter and Thrive. In July 2025, the company reported annualized revenue of $12 billion. This was an increase from $3.7 billion in 2024, which was driven by ChatGPT subscriptions, which reached 20 million paid subscribers by April 2025, up from 15.5 million at the end of 2024, alongside a rapidly expanding enterprise customer base that grew to five million business users. The company’s cash burn remains high because of the intensive computational costs required to train and operate large language models. It projects an $8 billion operating loss in 2025. OpenAI reports revised long-term spending projections totaling approximately $115 billion through 2029, with annual expenditures projected to escalate significantly, reaching $17 billion in 2026, $35 billion in 2027, and $45 billion in 2028. These expenditures are primarily allocated toward expanding compute infrastructure, developing proprietary AI chips, constructing data centers, and funding intensive model training programs, with more than half of the spending through the end of the decade expected to support research-intensive compute for model training and development. The company's financial strategy prioritizes market expansion and technological advancement over near-term profitability, with OpenAI targeting cash-flow-positive operations by 2029 and projecting revenue of approximately $200 billion by 2030. This aggressive spending trajectory underscores both the enormous capital requirements of scaling cutting-edge AI technology and OpenAI's commitment to maintaining its position as a leader in the artificial intelligence industry. In October 2025, OpenAI completed an employee share sale of up to $10 billion to existing investors which valued the company at $500 billion. The deal values OpenAI as the most valuable privately owned company in the world—surpassing SpaceX as the world's most valuable private company. On November 17, 2023, Sam Altman was removed as CEO when its board of directors (composed of Helen Toner, Ilya Sutskever, Adam D'Angelo and Tasha McCauley) cited a lack of confidence in him. Chief Technology Officer Mira Murati took over as interim CEO. Greg Brockman, the president of OpenAI, was also removed as chairman of the board and resigned from the company's presidency shortly thereafter. Three senior OpenAI researchers subsequently resigned: director of research and GPT-4 lead Jakub Pachocki, head of AI risk Aleksander Mądry, and researcher Szymon Sidor. On November 18, 2023, there were reportedly talks of Altman returning as CEO amid pressure placed upon the board by investors such as Microsoft and Thrive Capital, who objected to Altman's departure. Although Altman himself spoke in favor of returning to OpenAI, he has since stated that he considered starting a new company and bringing former OpenAI employees with him if talks to reinstate him didn't work out. The board members agreed "in principle" to resign if Altman returned. On November 19, 2023, negotiations with Altman to return failed and Murati was replaced by Emmett Shear as interim CEO. The board initially contacted Anthropic CEO Dario Amodei (a former OpenAI executive) about replacing Altman, and proposed a merger of the two companies, but both offers were declined. On November 20, 2023, Microsoft CEO Satya Nadella announced Altman and Brockman would be joining Microsoft to lead a new advanced AI research team, but added that they were still committed to OpenAI despite recent events. Before the partnership with Microsoft was finalized, Altman gave the board another opportunity to negotiate with him. About 738 of OpenAI's 770 employees, including Murati and Sutskever, signed an open letter stating they would quit their jobs and join Microsoft if the board did not rehire Altman and then resign. This prompted OpenAI investors to consider legal action against the board as well. In response, OpenAI management sent an internal memo to employees stating that negotiations with Altman and the board had resumed and would take some time. On November 21, 2023, after continued negotiations, Altman and Brockman returned to the company in their prior roles along with a reconstructed board made up of new members Bret Taylor (as chairman) and Lawrence Summers, with D'Angelo remaining. According to subsequent reporting, shortly before Altman’s firing, some employees raised concerns to the board about how he had handled the safety implications of a recent internal AI capability discovery. On November 29, 2023, OpenAI announced that an anonymous Microsoft employee had joined the board as a non-voting member to observe the company's operations; Microsoft resigned from the board in July 2024. In February 2024, the Securities and Exchange Commission subpoenaed OpenAI's internal communication to determine if Altman's alleged lack of candor misled investors. In 2024, following the temporary removal of Sam Altman and his return, many employees gradually left OpenAI, including most of the original leadership team and a significant number of AI safety researchers. In August 2023, it was announced that OpenAI had acquired the New York-based start-up Global Illumination, a company that deploys AI to develop digital infrastructure and creative tools. In June 2024, OpenAI acquired Multi, a startup focused on remote collaboration. In March 2025, OpenAI reached a deal with CoreWeave to acquire $350 million worth of CoreWeave shares and access to AI infrastructure, in return for $11.9 billion paid over five years. Microsoft was already CoreWeave's biggest customer in 2024. Alongside their other business dealings, OpenAI and Microsoft were renegotiating the terms of their partnership to facilitate a potential future initial public offering by OpenAI, while ensuring Microsoft's continued access to advanced AI models. On May 21, OpenAI announced the $6.5 billion acquisition of io, an AI hardware start-up founded by former Apple designer Jony Ive in 2024. In September 2025, OpenAI agreed to acquire the product testing startup Statsig for $1.1 billion in an all-stock deal and appointed Statsig's founding CEO Vijaye Raji as OpenAI's chief technology officer of applications. The company also announced development of an AI-driven hiring service designed to rival LinkedIn. OpenAI acquired personal finance app Roi in October 2025. In October 2025, OpenAI acquired Software Applications Incorporated, the developer of Sky, a macOS-based natural language interface designed to operate across desktop applications. The Sky team joined OpenAI, and the company announced plans to integrate Sky’s capabilities into ChatGPT. In December 2025, it was announced OpenAI had agreed to acquire Neptune, an AI tooling startup that helps companies track and manage model training, for an undisclosed amount. In January 2026, it was announced OpenAI had acquired healthcare technology startup Torch for approximately $60 million. The acquisition followed the launch of OpenAI’s ChatGPT Health product and was intended to strengthen the company’s medical data and healthcare artificial intelligence capabilities. OpenAI has been criticized for outsourcing the annotation of data sets to Sama, a company based in San Francisco that employed workers in Kenya. These annotations were used to train an AI model to detect toxicity, which could then be used to moderate toxic content, notably from ChatGPT's training data and outputs. However, these pieces of text usually contained detailed descriptions of various types of violence, including sexual violence. The investigation uncovered that OpenAI began sending snippets of data to Sama as early as November 2021. The four Sama employees interviewed by Time described themselves as mentally scarred. OpenAI paid Sama $12.50 per hour of work, and Sama was redistributing the equivalent of between $1.32 and $2.00 per hour post-tax to its annotators. Sama's spokesperson said that the $12.50 was also covering other implicit costs, among which were infrastructure expenses, quality assurance and management. In 2024, OpenAI began collaborating with Broadcom to design a custom AI chip capable of both training and inference, targeted for mass production in 2026 and to be manufactured by TSMC on a 3 nm process node. This initiative intended to reduce OpenAI's dependence on Nvidia GPUs, which are costly and face high demand in the market. In January 2024, Arizona State University purchased ChatGPT Enterprise in OpenAI's first deal with a university. In June 2024, Apple Inc. signed a contract with OpenAI to integrate ChatGPT features into its products as part of its new Apple Intelligence initiative. In June 2025, OpenAI began renting Google Cloud's Tensor Processing Units (TPUs) to support ChatGPT and related services, marking its first meaningful use of non‑Nvidia AI chips. In September 2025, it was revealed that OpenAI signed a contract with Oracle to purchase $300 billion in computing power over the next five years. In September 2025, OpenAI and NVIDIA announced a memorandum of understanding that included a potential deployment of at least 10 gigawatts of NVIDIA systems and a $100 billion investment from NVIDIA in OpenAI. OpenAI expected the negotiations to be completed within weeks. As of January 2026, this has not been realized, and the two sides are rethinking the future of their partnership. In October 2025, OpenAI announced a multi-billion dollar deal with AMD. OpenAI committed to purchasing six gigawatts worth of AMD chips, starting with the MI450. OpenAI will have the option to buy up to 160 million shares of AMD, about 10% of the company, depending on development, performance and share price targets. In December 2025, Disney said it would make a $1 billion investment in OpenAI, and signed a three-year licensing deal that will let users generate videos using Sora—OpenAI's short-form AI video platform. More than 200 Disney, Marvel, Star Wars and Pixar characters will be available to OpenAI users. In early 2026, Amazon entered advanced discussions to invest up to $50 billion in OpenAI as part of a potential artificial intelligence partnership. Under the proposed agreement, OpenAI’s models could be integrated into Amazon’s digital assistant Alexa and other internal projects. OpenAI provides LLMs to the Artificial Intelligence Cyber Challenge and to the Advanced Research Projects Agency for Health. In October 2024, The Intercept revealed that OpenAI's tools are considered "essential" for AFRICOM's mission and included in an "Exception to Fair Opportunity" contractual agreement between the United States Department of Defense and Microsoft. In December 2024, OpenAI said it would partner with defense-tech company Anduril to build drone defense technologies for the United States and its allies. In 2025, OpenAI's Chief Product Officer, Kevin Weil, was commissioned lieutenant colonel in the U.S. Army to join Detachment 201 as senior advisor. In June 2025, the U.S. Department of Defense awarded OpenAI a $200 million one-year contract to develop AI tools for military and national security applications. OpenAI announced a new program, OpenAI for Government, to give federal, state, and local governments access to its models, including ChatGPT. Services In February 2019, GPT-2 was announced, which gained attention for its ability to generate human-like text. In 2020, OpenAI announced GPT-3, a language model trained on large internet datasets. GPT-3 is aimed at natural language answering questions, but it can also translate between languages and coherently generate improvised text. It also announced that an associated API, named the API, would form the heart of its first commercial product. Eleven employees left OpenAI, mostly between December 2020 and January 2021, in order to establish Anthropic. In 2021, OpenAI introduced DALL-E, a specialized deep learning model adept at generating complex digital images from textual descriptions, utilizing a variant of the GPT-3 architecture. In December 2022, OpenAI received widespread media coverage after launching a free preview of ChatGPT, its new AI chatbot based on GPT-3.5. According to OpenAI, the preview received over a million signups within the first five days. According to anonymous sources cited by Reuters in December 2022, OpenAI Global, LLC was projecting $200 million of revenue in 2023 and $1 billion in revenue in 2024. After ChatGPT was launched, Google announced a similar chatbot, Bard, amid internal concerns that ChatGPT could threaten Google’s position as a primary source of online information. On February 7, 2023, Microsoft announced that it was building AI technology based on the same foundation as ChatGPT into Microsoft Bing, Edge, Microsoft 365 and other products. On March 14, 2023, OpenAI released GPT-4, both as an API (with a waitlist) and as a feature of ChatGPT Plus. On November 6, 2023, OpenAI launched GPTs, allowing individuals to create customized versions of ChatGPT for specific purposes, further expanding the possibilities of AI applications across various industries. On November 14, 2023, OpenAI announced they temporarily suspended new sign-ups for ChatGPT Plus due to high demand. Access for newer subscribers re-opened a month later on December 13. In December 2024, the company launched the Sora model. It also launched OpenAI o1, an early reasoning model that was internally codenamed strawberry. Additionally, ChatGPT Pro—a $200/month subscription service offering unlimited o1 access and enhanced voice features—was introduced, and preliminary benchmark results for the upcoming OpenAI o3 models were shared. On January 23, 2025, OpenAI released Operator, an AI agent and web automation tool for accessing websites to execute goals defined by users. The feature was only available to Pro users in the United States. OpenAI released deep research agent, nine days later. It scored a 27% accuracy on the benchmark Humanity's Last Exam (HLE). Altman later stated GPT-4.5 would be the last model without full chain-of-thought reasoning. In July 2025, reports indicated that AI models by both OpenAI and Google DeepMind solved mathematics problems at the level of top-performing students in the International Mathematical Olympiad. OpenAI's large language model was able to achieve gold medal-level performance, reflecting significant progress in AI's reasoning abilities. On October 6, 2025, OpenAI unveiled its Agent Builder platform during the company's DevDay event. The platform includes a visual drag-and-drop interface that lets developers and businesses design, test, and deploy agentic workflows with limited coding. On October 21, 2025, OpenAI introduced ChatGPT Atlas, a browser integrating the ChatGPT assistant directly into web navigation, to compete with existing browsers such as Google Chrome and Apple Safari. On December 11, 2025, OpenAI announced GPT-5.2. This model will be better at creating spreadsheets, building presentations, perceiving images, writing code and understanding long context. On January 27, 2026, OpenAI introduced Prism, a LaTeX-native workspace meant to assist scientists to help with research and writing. The platform utilizes GPT-5.2 as a backend to automate the process of drafting for scientific papers, including features for managing citations, complex equation formatting, and real-time collaborative editing. In March 2023, the company was criticized for disclosing particularly few technical details about products like GPT-4, contradicting its initial commitment to openness and making it harder for independent researchers to replicate its work and develop safeguards. OpenAI cited competitiveness and safety concerns to justify this repudiation. OpenAI's former chief scientist Ilya Sutskever argued in 2023 that open-sourcing increasingly capable models was increasingly risky, and that the safety reasons for not open-sourcing the most potent AI models would become "obvious" in a few years. In September 2025, OpenAI published a study on how people use ChatGPT for everyday tasks. The study found that "non-work tasks" (according to an LLM-based classifier) account for more than 72 percent of all ChatGPT usage, with a minority of overall usage related to business productivity. In July 2023, OpenAI launched the superalignment project, aiming within four years to determine how to align future superintelligent systems. OpenAI promised to dedicate 20% of its computing resources to the project, although the team denied receiving anything close to 20%. OpenAI ended the project in May 2024 after its co-leaders Ilya Sutskever and Jan Leike left the company. In August 2025, OpenAI was criticized after thousands of private ChatGPT conversations were inadvertently exposed to public search engines like Google due to an experimental "share with search engines" feature. The opt-in toggle, intended to allow users to make specific chats discoverable, resulted in some discussions including personal details such as names, locations, and intimate topics appearing in search results when users accidentally enabled it while sharing links. OpenAI announced the feature's permanent removal on August 1, 2025, and the company began coordinating with search providers to remove the exposed content, emphasizing that it was not a security breach but a design flaw that heightened privacy risks. CEO Sam Altman acknowledged the issue in a podcast, noting users often treat ChatGPT as a confidant for deeply personal matters, which amplified concerns about AI handling sensitive data. Management In 2018, Musk resigned from his Board of Directors seat, citing "a potential future conflict [of interest]" with his role as CEO of Tesla due to Tesla's AI development for self-driving cars. OpenAI stated that Musk's financial contributions were below $45 million. On March 3, 2023, Reid Hoffman resigned from his board seat, citing a desire to avoid conflicts of interest with his investments in AI companies via Greylock Partners, and his co-founding of the AI startup Inflection AI. Hoffman remained on the board of Microsoft, a major investor in OpenAI. In May 2024, Chief Scientist Ilya Sutskever resigned and was succeeded by Jakub Pachocki. Co-leader Jan Leike also departed amid concerns over safety and trust. OpenAI then signed deals with Reddit, News Corp, Axios, and Vox Media. Paul Nakasone then joined the board of OpenAI. In August 2024, cofounder John Schulman left OpenAI to join Anthropic, and OpenAI's president Greg Brockman took extended leave until November. In September 2024, CTO Mira Murati left the company. In November 2025, Lawrence Summers resigned from the board of directors. Governance and legal issues In May 2023, Sam Altman, Greg Brockman and Ilya Sutskever posted recommendations for the governance of superintelligence. They stated that superintelligence could happen within the next 10 years, allowing a "dramatically more prosperous future" and that "given the possibility of existential risk, we can't just be reactive". They proposed creating an international watchdog organization similar to IAEA to oversee AI systems above a certain capability threshold, suggesting that relatively weak AI systems on the other side should not be overly regulated. They also called for more technical safety research for superintelligences, and asked for more coordination, for example through governments launching a joint project which "many current efforts become part of". In July 2023, the FTC issued a civil investigative demand to OpenAI to investigate whether the company's data security and privacy practices to develop ChatGPT were unfair or harmed consumers (including by reputational harm) in violation of Section 5 of the Federal Trade Commission Act of 1914. These are typically preliminary investigative matters and are nonpublic, but the FTC's document was leaked. In July 2023, the FTC launched an investigation into OpenAI over allegations that the company scraped public data and published false and defamatory information. They asked OpenAI for comprehensive information about its technology and privacy safeguards, as well as any steps taken to prevent the recurrence of situations in which its chatbot generated false and derogatory content about people. The agency also raised concerns about ‘circular’ spending arrangements—for example, Microsoft extending Azure credits to OpenAI while both companies shared engineering talent—and warned that such structures could negatively affect the public. In September 2024, OpenAI's global affairs chief endorsed the UK's "smart" AI regulation during testimony to a House of Lords committee. In February 2025, OpenAI CEO Sam Altman stated that the company is interested in collaborating with the People's Republic of China, despite regulatory restrictions imposed by the U.S. government. This shift comes in response to the growing influence of the Chinese artificial intelligence company DeepSeek, which has disrupted the AI market with open models, including DeepSeek V3 and DeepSeek R1. Following DeepSeek's market emergence, OpenAI enhanced security protocols to protect proprietary development techniques from industrial espionage. Some industry observers noted similarities between DeepSeek's model distillation approach and OpenAI's methodology, though no formal intellectual property claim was filed. According to Oliver Roberts, in March 2025, the United States had 781 state AI bills or laws. OpenAI advocated for preempting state AI laws with federal laws. According to Scott Kohler, OpenAI has opposed California's AI legislation and suggested that the state bill encroaches on a more competent federal government. Public Citizen opposed a federal preemption on AI and pointed to OpenAI's growth and valuation as evidence that existing state laws have not hampered innovation. Before May 2024, OpenAI required departing employees to sign a lifelong non-disparagement agreement forbidding them from criticizing OpenAI and acknowledging the existence of the agreement. Daniel Kokotajlo, a former employee, publicly stated that he forfeited his vested equity in OpenAI in order to leave without signing the agreement. Sam Altman stated that he was unaware of the equity cancellation provision, and that OpenAI never enforced it to cancel any employee's vested equity. However, leaked documents and emails refute this claim. On May 23, 2024, OpenAI sent a memo releasing former employees from the agreement. OpenAI was sued for copyright infringement by authors Sarah Silverman, Matthew Butterick, Paul Tremblay and Mona Awad in July 2023. In September 2023, 17 authors, including George R. R. Martin, John Grisham, Jodi Picoult and Jonathan Franzen, joined the Authors Guild in filing a class action lawsuit against OpenAI, alleging that the company's technology was illegally using their copyrighted work. The New York Times also sued the company in late December 2023. In May 2024 it was revealed that OpenAI had destroyed its Books1 and Books2 training datasets, which were used in the training of GPT-3, and which the Authors Guild believed to have contained over 100,000 copyrighted books. In 2021, OpenAI developed a speech recognition tool called Whisper. OpenAI used it to transcribe more than one million hours of YouTube videos into text for training GPT-4. The automated transcription of YouTube videos raised concerns within OpenAI employees regarding potential violations of YouTube's terms of service, which prohibit the use of videos for applications independent of the platform, as well as any type of automated access to its videos. Despite these concerns, the project proceeded with notable involvement from OpenAI's president, Greg Brockman. The resulting dataset proved instrumental in training GPT-4. In February 2024, The Intercept as well as Raw Story and Alternate Media Inc. filed lawsuit against OpenAI on copyright litigation ground. The lawsuit is said to have charted a new legal strategy for digital-only publishers to sue OpenAI. On April 30, 2024, eight newspapers filed a lawsuit in the Southern District of New York against OpenAI and Microsoft, claiming illegal harvesting of their copyrighted articles. The suing publications included The Mercury News, The Denver Post, The Orange County Register, St. Paul Pioneer Press, Chicago Tribune, Orlando Sentinel, Sun Sentinel, and New York Daily News. In June 2023, a lawsuit claimed that OpenAI scraped 300 billion words online without consent and without registering as a data broker. It was filed in San Francisco, California, by sixteen anonymous plaintiffs. They also claimed that OpenAI and its partner as well as customer Microsoft continued to unlawfully collect and use personal data from millions of consumers worldwide to train artificial intelligence models. On May 22, 2024, OpenAI entered into an agreement with News Corp to integrate news content from The Wall Street Journal, the New York Post, The Times, and The Sunday Times into its AI platform. Meanwhile, other publications like The New York Times chose to sue OpenAI and Microsoft for copyright infringement over the use of their content to train AI models. In November 2024, a coalition of Canadian news outlets, including the Toronto Star, Metroland Media, Postmedia, The Globe and Mail, The Canadian Press and CBC, sued OpenAI for using their news articles to train its software without permission. In October 2024 during a New York Times interview, Suchir Balaji accused OpenAI of violating copyright law in developing its commercial LLMs which he had helped engineer. He was a likely witness in a major copyright trial against the AI company, and was one of several of its current or former employees named in court filings as potentially having documents relevant to the case. On November 26, 2024, Balaji died by suicide. His death prompted the circulation of conspiracy theories alleging that he had been deliberately silenced. California Congressman Ro Khanna endorsed calls for an investigation. On April 24, 2025, Ziff Davis sued OpenAI in Delaware federal court for copyright infringement. Ziff Davis is known for publications such as ZDNet, PCMag, CNET, IGN and Lifehacker. In April 2023, the EU's European Data Protection Board (EDPB) formed a dedicated task force on ChatGPT "to foster cooperation and to exchange information on possible enforcement actions conducted by data protection authorities" based on the "enforcement action undertaken by the Italian data protection authority against OpenAI about the ChatGPT service". In late April 2024 NOYB filed a complaint with the Austrian Datenschutzbehörde against OpenAI for violating the European General Data Protection Regulation. A text created with ChatGPT gave a false date of birth for a living person without giving the individual the option to see the personal data used in the process. A request to correct the mistake was denied. Additionally, neither the recipients of ChatGPT's work nor the sources used, could be made available, OpenAI claimed. OpenAI was criticized for lifting its ban on using ChatGPT for "military and warfare". Up until January 10, 2024, its "usage policies" included a ban on "activity that has high risk of physical harm, including", specifically, "weapons development" and "military and warfare". Its new policies prohibit "[using] our service to harm yourself or others" and to "develop or use weapons". In August 2025, the parents of a 16-year-old boy who died by suicide filed a wrongful death lawsuit against OpenAI (and CEO Sam Altman), alleging that months of conversations with ChatGPT about mental health and methods of self-harm contributed to their son's death and that safeguards were inadequate for minors. OpenAI expressed condolences and said it was strengthening protections (including updated crisis response behavior and parental controls). Coverage described it as a first-of-its-kind wrongful death case targeting the company's chatbot. The complaint was filed in California state court in San Francisco. In November 2025, the Social Media Victims Law Center and Tech Justice Law Project filed seven lawsuits against OpenAI, of which four lawsuits alleged wrongful death. The suits were filed on behalf of Zane Shamblin, 23, of Texas; Amaurie Lacey, 17, of Georgia; Joshua Enneking, 26, of Florida; and Joe Ceccanti, 48, of Oregon, who each committed suicide after prolonged ChatGPT usage. In December 2025, Stein-Erik Soelberg, who was 56 years old at the time, allegedly murdered his mother Suzanne Adams. In the months prior the paranoid, delusional man often discussed his ideas with ChatGPT. Adam's estate then sued OpenAI claiming that the company shared responsibility due to the risk of chatbot psychosis despite the fact that chatbot psychosis is not a real medical diagnosis. OpenAI responded saying they will make ChatGPT safer for users disconnected from reality. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Sylph] | [TOKENS: 1902] |
Contents Sylph A sylph (also called sylphid) is an air spirit stemming from the 16th-century works of Paracelsus, who describes sylphs as (invisible) beings of the air, his elementals of air. A significant number of subsequent literary and occult works have been inspired by Paracelsus's concept: Robert Alfred Vaughan noted that "the wild but poetical fantasies" of Paracelsus had probably exercised a larger influence over his age and the subsequent one than is generally supposed, particularly on the Rosicrucians, but that through the 18th century they had become reduced to "machinery for the playwright" and "opera figurantes with wings of gauze and spangles". Etymology "Sylph" is possibly a blend of from Latin sylvestris and nympha, sylvestris being a common synonym for sylph in Paracelsus. Anthony Trollope note a similar usage in the Aeneid, where silvestris is taken as an elliptical form of nympha silvestris ("forest nymph"). Jacob Grimm uses this phrase as a gloss for the Anglo-Saxon wudu-mær (roughly equivalent to "woodmare"), which he also takes as a metaphorical name for an echo. Jan Baptist van Helmont, a near contemporary of Paracelsus and coiner of the word "gas", uses sylvestris in the sense of "wild" to describe gaseous emissions, which may be connected to the Paracelsian usage. Thorpe's Northern Mythology connects the adjective sylvestres and the related silvaticas to European wild man legends. A related idea is that "sylph" is from a hyper-urbane respelling of a Latin neologism silves, but in either case this connection to the Latin root silva ("forest") is supported by Paracelsus' use of sylphes as a synonym for schrötlein, a German word for a tree spirit or especially an earth spirit in his Liber de Sanguine ultra Mortem. An alternative theory is that it derives from sílphē (Ancient Greek: σίλφη, romanized: sílphē), which a number of etymological sources gloss as "moth". French etymological sources often derive it from a Latin word sylphus, glossed as "genius" (in the Latin sense, a type of spirit) and only known from an inscription rather than literary Latin. The Deutsches Wörterbuch however indicates that this idea arises from a 19th-century misreading of the inscription in question. Similarly, the σίλφη etymology can be dismissed from the lack of an objective historical and thus semantic connection. The idea of an intentional portmanteau is also considered doubtful, though extensive evidence can be found that indicates that Paracelsus considered the various sylvan spirits and wild men of legend to be examples of sylphs, which he occasionally took to be earth elementals rather than air elementals. Paracelsus' conception The Swiss German physician and alchemist Paracelsus first coined the term sylph in the 16th century to describe an air spirit in his overarching scheme of elemental spirits associated with the four Classical elements. Paracelsus drew from earlier sources, but his systematic treatment of the idea was definitive, with the names of three of the four types having originated in his works. The other three elemental spirits named were Gnomes (earth), Salamanders (fire), and Undines (water). These ideas were adopted in Rosicrucianism and were widely encountered in subsequent hermetic literature. In the Liber de Nymphis of the Philosophia Magna, Paracelsus discusses the characteristics of the elementals at length. Sylphs, he says, are rougher, coarser, taller, and stronger than humans. The elementals are said to be able to move through their own elements as human beings move through air. Because of this, sylphs are the closest to humans in his conception because they move through air like we do, while in fire they burn, in water they drown, and in earth, they get stuck. In literature Sylphs are mentioned by that name in the 1668 German novel Simplicius Simplicissimus, though its author Grimmelshausen seems to have taken them to be water spirits. The French pseudo-novel Comte de Gabalis (1670) was important in passing sylphs into the literary sphere. It appears to have originated the derivative term "sylphid" (French sylphide), which it uses as the feminine counterpart to "sylph". While modern scholars consider Comte de Gabalis to have been intended as a satire of occult philosophy, many of its contemporaries considered it to be an earnest exposition of occult lore. Its author, Abbé de Montfaucon de Villars, was assassinated on the road in 1673 and one rumor had it that he had been killed by a gang of sylphs for disclosing their secrets. One of the best-known discussions of sylphs comes with Alexander Pope. In Rape of the Lock (final ed. 1717), Pope satirizes French Rosicrucian and alchemical writings when he invents a theory to explain the sylph. In a parody of heroic poetry and the "dark" and "mysterious" alchemical literature, and in particular the sometimes esoterically Classical heroic poetry of the 18th century in England and France, Pope pretends to have a new alchemy, in which the sylph is the mystically, chemically condensed humors of peevish women. In Pope's poem, women who are full of spleen and vanity turn into sylphs when they die because their spirits are too full of dark vapors to ascend to the skies. Belinda, the heroine of Pope's poem, is attended by a small army of sylphs, who foster her vanity and guard her beauty. The poem is a parody of Paracelsian ideas, inasmuch as Pope imitates the pseudo-science of alchemy to explain the seriousness with which vain women approach the dressing room. In a slight parody of the divine battle in Pope's Rape of the Lock, when the Baron of the poem attempts to cut a lock of Belinda's hair, the sylphs interpose their airy bodies between the blades of the scissors (to no effect whatsoever). Ariel, the chief sylph in the Rape of the Lock, has the same name as Prospero's servant Ariel in Shakespeare's The Tempest (ca. 1611), and Shakespeare's character is described literally as an "airy spirit" in the dramatis personae. This name was generally thought to have been original with Shakespeare, though the exact inspiration for the character is unclear. Pope explicitly cited Comte de Gabalis as a source for elemental lore in the dedication. In the 1778 British novel The Sylph, a sylph appears as a guardian spirit for the female protagonist. By 1765, the French author Jean-François Marmontel had found the sylph legend notable enough that he included among his Moral Tales the story of "the Sylph-Husband," in which a young woman obsessed with the idea of marrying a sylph is deluded into falling in love with her arranged-husband after he impersonates one. In Fernando Pessoa's "Book of Disquiet", (entry 214 - New Directions, 2017) he writes (translated from the Portuguese by Margaret Jill Costa): "And as with books so with everything else...Given that anything can be dreamed to serve as a real interruption to the silent flow of my days, I raise eyes of weary protest to the sylph who is mine alone, to the poor girl who, had she only learned to sing, could perhaps have been a siren". In ballet and opera The famous ballet La Sylphide ("The (Female) Sylph", Paris, 1832) is a prominent example of sylph lore in theater in the 19th century. It appeared in a second version in Denmark in 1836. A similarly themed opera The Mountain Sylph appeared in England in 1834. Sylphs again took to the stage in the 1909 ballet Les Sylphides. In popular culture Association with fairies Because of their association with the ballet La Sylphide, where sylphs are identified with fairies and the medieval legends of fairyland, as well as a confusion with other "airy spirits" (e.g., in William Shakespeare's A Midsummer Night's Dream), a slender girl may be referred to as a sylph. "Sylph" has passed into general language as a term for minor spirits, elementals, or faeries of the air. Fantasy authors will sometimes employ sylphs in their fiction, for example creating giant artistic clouds in the skies with airy wings. See also References |
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[SOURCE: https://en.wikipedia.org/wiki/Special:BookSources/978-0-19-866209-9] | [TOKENS: 380] |
Contents Book sources This page allows users to search multiple sources for a book given a 10- or 13-digit International Standard Book Number. Spaces and dashes in the ISBN do not matter. This page links to catalogs of libraries, booksellers, and other book sources where you will be able to search for the book by its International Standard Book Number (ISBN). Online text Google Books and other retail sources below may be helpful if you want to verify citations in Wikipedia articles, because they often let you search an online version of the book for specific words or phrases, or you can browse through the book (although for copyright reasons the entire book is usually not available). At the Open Library (part of the Internet Archive) you can borrow and read entire books online. Online databases Subscription eBook databases Libraries Alabama Alaska California Colorado Connecticut Delaware Florida Georgia Illinois Indiana Iowa Kansas Kentucky Massachusetts Michigan Minnesota Missouri Nebraska New Jersey New Mexico New York North Carolina Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Washington state Wisconsin Bookselling and swapping Find your book on a site that compiles results from other online sites: These sites allow you to search the catalogs of many individual booksellers: Non-English book sources If the book you are looking for is in a language other than English, you might find it helpful to look at the equivalent pages on other Wikipedias, linked below – they are more likely to have sources appropriate for that language. Find other editions The WorldCat xISBN tool for finding other editions is no longer available. However, there is often a "view all editions" link on the results page from an ISBN search. Google books often lists other editions of a book and related books under the "about this book" link. You can convert between 10 and 13 digit ISBNs with these tools: Find on Wikipedia See also Get free access to research! Research tools and services Outreach Get involved |
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[SOURCE: https://en.wikipedia.org/wiki/Extraterrestrial_life#cite_note-55] | [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 |
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Contents Ministry of Education (Israel) The Ministry of Education (Hebrew: מִשְׂרָד הַחִנּוּךְ, translit. Misrad HaHinukh; Arabic: وزارة التربية والتعليم) is the branch of the Israeli government charged with overseeing public education institutions in Israel. The department is headed by the Minister of Education, who is a member of the cabinet. The ministry has previously included culture and sport, although this is now covered by the Ministry of Culture and Sport. History In the first decade of statehood, the education system was faced with the task of establishing a network of kindergartens and schools for a rapidly growing student population. In 1949, there were 80,000 elementary school students. By 1950, there were 120,000 - an increase of 50 percent within the span of one year. Israel also took over responsibility for the education of Arab schoolchildren. The first minister of education was Zalman Shazar, later president of the State of Israel. Since 2002, the Ministry of Education has awarded a National Education Award to five top localities in recognizing excellence in investing substantial resources in the educational system. In 2012, first place was awarded to the Shomron Regional Council and followed by Or Yehuda, Tiberias, Eilat and Beersheba. The prize has been awarded to a variety of educational institutions including kindergartens and elementary schools. In 2013–2014, the Ministry of Education promoted the regulation of the activities of external parties within the state schools, in a dialogue between the Ministry, the local government, parents' representatives, the business sector and philanthropic parties, as part of what was called "the intersectoral round table in the Ministry of Education". As part of the regulation, the Ministry compiled a database of external programs that have some kind of partnership with a representative from the Ministry of Education's headquarters. In 2019, a petition was filed by pluralist Jewish organizations against the Ministry of Education due to a procedure that reduces by tens of thousands of shekels the support for the activities of these organizations in schools. In April 2021, the High Court invalidated the procedure in question, and even emphasized the importance of implementing the principles of the Shanhar Committee report on the teaching of Judaism in state education. In November 2021 it was announced that the Ministry of Education is not implementing the High Court ruling and that the damage to those organizations continues. List of ministers References External links |
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Contents Middle East The Middle East[b] is a geopolitical region encompassing the Arabian Peninsula, Egypt, Iran, Iraq, the Levant, and Turkey. The term came into widespread usage by Western European nations in the early 20th century as a replacement of the term Near East (both were in contrast to the Far East). The term "Middle East" has led to some confusion over its changing definitions. Since the late 20th century, it has been criticized as being too Eurocentric. The region includes the vast majority of the territories included in the closely associated definition of West Asia, but without the South Caucasus. It also includes all of Egypt (not just the Sinai region) and all of Turkey (including East Thrace). Most Middle Eastern countries (13 out of 18) are part of the Arab world. The three most populous countries in the region are Egypt, Iran, and Turkey, while Saudi Arabia is the largest Middle Eastern country by area. The history of the Middle East dates back to ancient times, and it was long considered the "cradle of civilization". The geopolitical importance of the region has been recognized and competed for during millennia. The Abrahamic religions (Judaism, Christianity, and Islam) have their origins in the Middle East. Arabs constitute the main ethnic group in the region, followed by Turks, Persians, Kurds, Jews, and Assyrians. The Middle East generally has a hot, arid climate, especially in the Arabian and Egyptian regions. Several major rivers provide irrigation to support agriculture in limited areas here, such as the Nile Delta in Egypt, the Tigris and Euphrates watersheds of Mesopotamia, and the basin of the Jordan River that spans most of the Levant. These regions are collectively known as the Fertile Crescent, and comprise the core of what historians had long referred to as the cradle of civilization; multiple regions of the world have since been classified as also having developed independent, original civilizations. Conversely, the Levantine coast and most of Turkey have relatively temperate climates typical of the Mediterranean, with dry summers and cool, wet winters. Most of the countries that border the Persian Gulf have vast reserves of petroleum. Monarchs of the Arabian Peninsula in particular have benefitted economically from petroleum exports. Because of the arid climate and dependence on the fossil fuel industry, the Middle East is both a major contributor to climate change and a region that is expected to be severely adversely affected by it. Other concepts of the region exist, including the broader Middle East and North Africa (MENA), which includes states of the Maghreb and the Sudan. The term the "Greater Middle East" also includes Afghanistan, Mauritania, Pakistan, as well as parts of East Africa, and sometimes Central Asia and the South Caucasus. Terminology The term "Middle East" may have originated in the 1850s in the British India Office. However, it became more widely known when United States naval strategist Alfred Thayer Mahan used the term in 1902 to "designate the area between Arabia and India". During this time the British and Russian empires were vying for influence in Central Asia, a rivalry that would become known as the Great Game. Mahan realized not only the strategic importance of the region, but also of its center, the Persian Gulf. He labeled the area surrounding the Persian Gulf as the Middle East. He said that, beyond Egypt's Suez Canal, the Gulf was the most important passage for Britain to control in order to keep the Russians from advancing towards British India. Mahan first used the term in his article "The Persian Gulf and International Relations", published in September 1902 in the National Review, a British journal. The Middle East, if I may adopt a term which I have not seen, will some day need its Malta, as well as its Gibraltar; it does not follow that either will be in the Persian Gulf. Naval force has the quality of mobility which carries with it the privilege of temporary absences; but it needs to find on every scene of operation established bases of refit, of supply, and in case of disaster, of security. The British Navy should have the facility to concentrate in force if occasion arise, about Aden, India, and the Persian Gulf. Mahan's article was reprinted in The Times and followed in October by a 20-article series entitled "The Middle Eastern Question", written by Sir Ignatius Valentine Chirol. During this series, Sir Ignatius expanded the definition of Middle East to include "those regions of Asia which extend to the borders of India or command the approaches to India." After the series ended in 1903, The Times removed quotation marks from subsequent uses of the term. Until World War II, it was customary to refer to areas centered on Turkey and the eastern shore of the Mediterranean as the "Near East", while the "Far East" centered on China, India and Japan. The Middle East was then defined as the area from Mesopotamia to Burma; namely, the area between the Near East and the Far East. This area broadly corresponds to South Asia. In the late 1930s, the British established the Middle East Command, which was based in Cairo, for its military forces in the region. After that time, the term "Middle East" gained broader usage in Europe and the United States. Following World War II, for example, the Middle East Institute was founded in Washington, D.C. in 1946. The corresponding adjective is Middle Eastern and the derived noun is Middle Easterner. While non-Eurocentric terms such as "Southwest Asia" or "Swasia" have been sparsely used, the classification of the African country, Egypt, among those counted in the Middle East challenges the usefulness of using such terms. The description Middle has also led to some confusion over changing definitions. Before the First World War, "Near East" was used in English to refer to the Balkans and the Ottoman Empire, while "Middle East" referred to the Caucasus, Persia, and Arabian lands, and sometimes Afghanistan, India and others. In contrast, "Far East" referred to the countries of East Asia (e.g. China, Japan, and Korea). With the collapse of the Ottoman Empire in 1918, "Near East" largely fell out of common use in English, while "Middle East" came to be applied to the emerging independent countries of the Islamic world. However, the usage "Near East" was retained by a variety of academic disciplines, including archaeology and ancient history. In their usage, the term describes an area identical to the term Middle East, which is not used by these disciplines (see ancient Near East).[citation needed] The first official use of the term "Middle East" by the United States government was in the 1957 Eisenhower Doctrine, which pertained to the Suez Crisis. Secretary of State John Foster Dulles defined the Middle East as "the area lying between and including Libya on the west and Pakistan on the east, Syria and Iraq on the North and the Arabian peninsula to the south, plus the Sudan and Ethiopia." In 1958, the State Department explained that the terms "Near East" and "Middle East" were interchangeable, and defined the region as including only Egypt, Syria, Israel, Lebanon, Jordan, Iraq, Saudi Arabia, Kuwait, Bahrain, and Qatar. Since the late 20th century, scholars and journalists from the region, such as journalist Louay Khraish and historian Hassan Hanafi have criticized the use of "Middle East" as a Eurocentric and colonialist term. The Associated Press Stylebook of 2004 says that Near East formerly referred to the farther west countries while Middle East referred to the eastern ones, but that now they are synonymous. It instructs: Use Middle East unless Near East is used by a source in a story. Mideast is also acceptable, but Middle East is preferred. European languages have adopted terms similar to Near East and Middle East. Since these are based on a relative description, the meanings depend on the country and are generally different from the English terms. In German the term Naher Osten (Near East) is still in common use (nowadays the term Mittlerer Osten is more and more common in press texts translated from English sources, albeit having a distinct meaning). In the four Slavic languages, Russian Ближний Восток or Blizhniy Vostok, Bulgarian Близкия Изток, Polish Bliski Wschód or Croatian Bliski istok (terms meaning Near East are the only appropriate ones for the region). However, some European languages do have "Middle East" equivalents, such as French Moyen-Orient, Swedish Mellanöstern, Spanish Oriente Medio or Medio Oriente, Greek is Μέση Ανατολή (Mesi Anatoli), and Italian Medio Oriente.[c] Perhaps because of the political influence of the United States and Europe, and the prominence of Western press, the Arabic equivalent of Middle East (Arabic: الشرق الأوسط ash-Sharq al-Awsaṭ) has become standard usage in the mainstream Arabic press. It comprises the same meaning as the term "Middle East" in North American and Western European usage. The designation, Mashriq, also from the Arabic root for East, also denotes a variously defined region around the Levant, the eastern part of the Arabic-speaking world (as opposed to the Maghreb, the western part). Even though the term originated in the West, countries of the Middle East that use languages other than Arabic also use that term in translation. For instance, the Persian equivalent for Middle East is خاورمیانه (Khāvar-e miyāneh), the Hebrew is המזרח התיכון (hamizrach hatikhon), and the Turkish is Orta Doğu. Countries and territory Traditionally included within the Middle East are Arabia, Asia Minor, East Thrace, Egypt, Iran, the Levant, Mesopotamia, and the Socotra Archipelago. The region includes 17 UN-recognized countries and one British Overseas Territory. Various concepts are often paralleled to the Middle East, most notably the Near East, Fertile Crescent, and Levant. These are geographical concepts, which refer to large sections of the modern-day Middle East, with the Near East being the closest to the Middle East in its geographical meaning. Due to it primarily being Arabic speaking, the Maghreb region of North Africa is sometimes included. "Greater Middle East" is a political term coined by the second Bush administration in the first decade of the 21st century to denote various countries, pertaining to the Muslim world, specifically Afghanistan, Iran, Pakistan, and Turkey. Various Central Asian countries are sometimes also included. History The Middle East lies at the juncture of Africa and Eurasia and of the Indian Ocean and the Mediterranean Sea (see also: Indo-Mediterranean). It is the birthplace and spiritual center of religions such as Christianity, Islam, Judaism, Manichaeism, Yezidi, Druze, Yarsan, and Mandeanism, and in Iran, Mithraism, Zoroastrianism, Manicheanism, and the Baháʼí Faith. Throughout its history the Middle East has been a major center of world affairs; a strategically, economically, politically, culturally, and religiously sensitive area. The region is one of the regions where agriculture was independently discovered, and from the Middle East it was spread, during the Neolithic, to different regions of the world such as Europe, the Indus Valley and Eastern Africa. Prior to the formation of civilizations, advanced cultures formed all over the Middle East during the Stone Age. The search for agricultural lands by agriculturalists, and pastoral lands by herdsmen meant different migrations took place within the region and shaped its ethnic and demographic makeup. The Middle East is widely and most famously known as the cradle of civilization. The world's earliest civilizations, Mesopotamia (Sumer, Akkad, Assyria and Babylonia), ancient Egypt and Kish in the Levant, all originated in the Fertile Crescent and Nile Valley regions of the ancient Near East. These were followed by the Hittite, Greek, Hurrian and Urartian civilisations of Asia Minor; Elam, Persia and Median civilizations in Iran, as well as the civilizations of the Levant (such as Ebla, Mari, Nagar, Ugarit, Canaan, Aramea, Mitanni, Phoenicia and Israel) and the Arabian Peninsula (Magan, Sheba, Ubar). The Near East was first largely unified under the Neo Assyrian Empire, then the Achaemenid Empire followed later by the Macedonian Empire and after this to some degree by the Iranian empires (namely the Parthian and Sassanid Empires), the Roman Empire and Byzantine Empire. The region served as the intellectual and economic center of the Roman Empire and played an exceptionally important role due to its periphery on the Sassanid Empire. Thus, the Romans stationed up to five or six of their legions in the region for the sole purpose of defending it from Sassanid and Bedouin raids and invasions. From the 4th century CE onwards, the Middle East became the center of the two main powers at the time, the Byzantine Empire and the Sassanid Empire. However, it would be the later Islamic Caliphates of the Middle Ages, or Islamic Golden Age which began with the Islamic conquest of the region in the 7th century AD, that would first unify the entire Middle East as a distinct region and create the dominant Islamic Arab ethnic identity that largely (but not exclusively) persists today. The 4 caliphates that dominated the Middle East for more than 600 years were the Rashidun Caliphate, the Umayyad caliphate, the Abbasid caliphate and the Fatimid caliphate. Additionally, the Mongols would come to dominate the region, the Kingdom of Armenia would incorporate parts of the region to their domain, the Seljuks would rule the region and spread Turko-Persian culture, and the Franks would found the Crusader states that would stand for roughly two centuries. Josiah Russell estimates the population of what he calls "Islamic territory" as roughly 12.5 million in 1000 – Anatolia 8 million, Syria 2 million, and Egypt 1.5 million. From the 16th century onward, the Middle East came to be dominated, once again, by two main powers: the Ottoman Empire and the Safavid dynasty. The modern Middle East began after World War I, when the Ottoman Empire, which was allied with the Central Powers, was defeated by the Allies and partitioned into a number of separate nations, initially under British and French Mandates. Other defining events in this transformation included the establishment of Israel in 1948 and the eventual departure of European powers, notably Britain and France by the end of the 1960s. They were supplanted in some part by the rising influence of the United States from the 1970s onwards. In the 20th century, the region's significant stocks of crude oil gave it new strategic and economic importance. Mass production of oil began around 1945, with Saudi Arabia, Iran, Kuwait, Iraq, and the United Arab Emirates having large quantities of oil. Estimated oil reserves, especially in Saudi Arabia and Iran, are some of the highest in the world, and the international oil cartel OPEC is dominated by Middle Eastern countries. During the Cold War, the Middle East was a theater of ideological struggle between the two superpowers and their allies: NATO and the United States on one side, and the Soviet Union and Warsaw Pact on the other, as they competed to influence regional allies. Besides the political reasons there was also the "ideological conflict" between the two systems. Moreover, as Louise Fawcett argues, among many important areas of contention, or perhaps more accurately of anxiety, were, first, the desires of the superpowers to gain strategic advantage in the region, second, the fact that the region contained some two-thirds of the world's oil reserves in a context where oil was becoming increasingly vital to the economy of the Western world [...] Within this contextual framework, the United States sought to divert the Arab world from Soviet influence. Throughout the 20th and 21st centuries, the region has experienced both periods of relative peace and tolerance and periods of conflict particularly between Sunnis and Shiites. Geography In 2018, the MENA region emitted 3.2 billion tonnes of carbon dioxide and produced 8.7% of global greenhouse gas emissions (GHG) despite making up only 6% of the global population. These emissions are mostly from the energy sector, an integral component of many Middle Eastern and North African economies due to the extensive oil and natural gas reserves that are found within the region. The Middle East region is one of the most vulnerable to climate change. The impacts include increase in drought conditions, aridity, heatwaves and sea level rise. Sharp global temperature and sea level changes, shifting precipitation patterns and increased frequency of extreme weather events are some of the main impacts of climate change as identified by the Intergovernmental Panel on Climate Change (IPCC). The MENA region is especially vulnerable to such impacts due to its arid and semi-arid environment, facing climatic challenges such as low rainfall, high temperatures and dry soil. The climatic conditions that foster such challenges for MENA are projected by the IPCC to worsen throughout the 21st century. If greenhouse gas emissions are not significantly reduced, part of the MENA region risks becoming uninhabitable before the year 2100. Climate change is expected to put significant strain on already scarce water and agricultural resources within the MENA region, threatening the national security and political stability of all included countries. Over 60 percent of the region's population lives in high and very high water-stressed areas compared to the global average of 35 percent. This has prompted some MENA countries to engage with the issue of climate change on an international level through environmental accords such as the Paris Agreement. Law and policy are also being established on a national level amongst MENA countries, with a focus on the development of renewable energies. Economy Middle Eastern economies range from being very poor (such as Gaza and Yemen) to extremely wealthy nations (such as Qatar and UAE). According to the International Monetary Fund, the three largest Middle Eastern economies in nominal GDP in 2023 were Saudi Arabia ($1.06 trillion), Turkey ($1.03 trillion), and Israel ($0.54 trillion). For nominal GDP per person, the highest ranking countries are Qatar ($83,891), Israel ($55,535), the United Arab Emirates ($49,451) and Cyprus ($33,807). Turkey ($3.6 trillion), Saudi Arabia ($2.3 trillion), and Iran ($1.7 trillion) had the largest economies in terms of GDP PPP. For GDP PPP per person, the highest-ranking countries are Qatar ($124,834), the United Arab Emirates ($88,221), Saudi Arabia ($64,836), Bahrain ($60,596) and Israel ($54,997). The lowest-ranking country in the Middle East, in terms of GDP nominal per capita, is Yemen ($573). The economic structure of Middle Eastern nations are different because while some are heavily dependent on export of only oil and oil-related products (Saudi Arabia, the UAE and Kuwait), others have a highly diverse economic base (such as Cyprus, Israel, Turkey and Egypt). Industries of the Middle Eastern region include oil and oil-related products, agriculture, cotton, cattle, dairy, textiles, leather products, surgical instruments, defence equipment (guns, ammunition, tanks, submarines, fighter jets, UAVs, and missiles). Banking is an important sector, especially for UAE and Bahrain. With the exception of Cyprus, Turkey, Egypt, Lebanon and Israel, tourism has been a relatively undeveloped area of the economy, in part because of the socially conservative nature of the region as well as political turmoil in certain regions. Since the end of the COVID pandemic however, countries such as the UAE, Bahrain, and Jordan have begun attracting greater numbers of tourists because of improving tourist facilities and the relaxing of tourism-related restrictive policies. Unemployment is high in the Middle East and North Africa region, particularly among people aged 15–29, a demographic representing 30% of the region's population. The total regional unemployment rate in 2025 is 10.8%, and among youth is as high as 28%. Demographics Arabs constitute the largest ethnic group in the Middle East, followed by various Iranian peoples and then by Turkic peoples (Turkish, Azeris, Syrian Turkmen, and Iraqi Turkmen). Native ethnic groups of the region include, in addition to Arabs, Arameans, Assyrians, Baloch, Berbers, Copts, Druze, Greek Cypriots, Jews, Kurds, Lurs, Mandaeans, Persians, Samaritans, Shabaks, Tats, and Zazas. European ethnic groups that form a diaspora in the region include Albanians, Bosniaks, Circassians (including Kabardians), Crimean Tatars, Greeks, Franco-Levantines, Italo-Levantines, and Iraqi Turkmens. Among other migrant populations are Chinese, Filipinos, Indians, Indonesians, Pakistanis, Pashtuns, Romani, and Afro-Arabs. "Migration has always provided an important vent for labor market pressures in the Middle East. For the period between the 1970s and 1990s, the Arab states of the Persian Gulf in particular provided a rich source of employment for workers from Egypt, Yemen and the countries of the Levant, while Europe had attracted young workers from North African countries due both to proximity and the legacy of colonial ties between France and the majority of North African states." According to the International Organization for Migration, there are 13 million first-generation migrants from Arab nations in the world, of which 5.8 reside in other Arab countries. Expatriates from Arab countries contribute to the circulation of financial and human capital in the region and thus significantly promote regional development. In 2009 Arab countries received a total of US$35.1 billion in remittance in-flows and remittances sent to Jordan, Egypt and Lebanon from other Arab countries are 40 to 190 per cent higher than trade revenues between these and other Arab countries. In Somalia, the Somali Civil War has greatly increased the size of the Somali diaspora, as many of the best educated Somalis left for Middle Eastern countries as well as Europe and North America. Non-Arab Middle Eastern countries such as Turkey, Israel and Iran are also subject to important migration dynamics. A fair proportion of those migrating from Arab nations are from ethnic and religious minorities facing persecution and are not necessarily ethnic Arabs, Iranians or Turks.[citation needed] Large numbers of Kurds, Jews, Assyrians, Greeks and Armenians as well as many Mandeans have left nations such as Iraq, Iran, Syria and Turkey for these reasons during the last century. In Iran, many religious minorities such as Christians, Baháʼís, Jews and Zoroastrians have left since the Islamic Revolution of 1979. The Middle East is very diverse when it comes to religions, many of which originated there. Islam is the largest religion in the Middle East, but other faiths that originated there, such as Judaism and Christianity, are also well represented. Christian communities have played a vital role in the Middle East, and they represent 78% of Cyprus population, and 40.5% of Lebanon, where the Lebanese president, half of the cabinet, and half of the parliament follow one of the various Lebanese Christian rites. There are also important minority religions like the Baháʼí Faith, Yarsanism, Yazidism, Zoroastrianism, Mandaeism, Druze, and Shabakism, and in ancient times the region was home to Mesopotamian religions, Canaanite religions, Manichaeism, Mithraism and various monotheist gnostic sects. The six top languages, in terms of numbers of speakers, are Arabic, Persian, Turkish, Kurdish, Modern Hebrew and Greek. About 20 minority languages are also spoken in the Middle East. Arabic, with all its dialects, is the most widely spoken language in the Middle East, with Literary Arabic being official in all North African and in most West Asian countries. Arabic dialects are also spoken in some adjacent areas in neighbouring Middle Eastern non-Arab countries. It is a member of the Semitic branch of the Afro-Asiatic languages. Several Modern South Arabian languages such as Mehri and Soqotri are also spoken in Yemen and Oman. Another Semitic language is Aramaic and its dialects are spoken mainly by Assyrians and Mandaeans, with Western Aramaic still spoken in two villages near Damascus, Syria. There is also an Oasis Berber-speaking community in Egypt where the language is also known as Siwa. It is a non-Semitic Afro-Asiatic sister language. Persian is the second most spoken language. While it is primarily spoken in Iran and some border areas in neighbouring countries, the country is one of the region's largest and most populous. It belongs to the Indo-Iranian branch of the family of Indo-European languages. Other Western Iranic languages spoken in the region include Achomi, Daylami, Kurdish dialects, Semmani, Lurish, amongst many others. The close third-most widely spoken language, Turkish, is largely confined to Turkey, which is also one of the region's largest and most populous countries, but it is present in areas in neighboring countries. It is a member of the Turkic languages, which have their origins in East Asia. Another Turkic language, Azerbaijani, is spoken by Azerbaijanis in Iran. The fourth-most widely spoken language, Kurdish, is spoken in the countries of Iran, Iraq, Syria and Turkey, Sorani Kurdish is the second official language in Iraq (instated after the 2005 constitution) after Arabic. Hebrew is the official language of Israel, with Arabic given a special status after the 2018 Basic law lowered its status from an official language prior to 2018. Hebrew is spoken and used by over 80% of Israel's population, the other 20% using Arabic. Modern Hebrew only began being spoken in the 20th century after being revived in the late 19th century by Elizer Ben-Yehuda (Elizer Perlman) and European Jewish settlers, with the first native Hebrew speaker being born in 1882. Greek is one of the two official languages of Cyprus, and the country's main language. Small communities of Greek speakers exist all around the Middle East; until the 20th century it was also widely spoken in Asia Minor (being the second most spoken language there, after Turkish) and Egypt. During the antiquity, Ancient Greek was the lingua franca for many areas of the western Middle East and until the Muslim expansion it was widely spoken there as well. Until the late 11th century, it was also the main spoken language in Asia Minor; after that it was gradually replaced by the Turkish language as the Anatolian Turks expanded and the local Greeks were assimilated, especially in the interior. English is one of the official languages of Akrotiri and Dhekelia. It is also commonly taught and used as a foreign second language, in countries such as Egypt, Jordan, Iran, Iraq, Qatar, Bahrain, United Arab Emirates and Kuwait. It is also a main language in some Emirates of the United Arab Emirates. It is also spoken as native language by Jewish immigrants from Anglophone countries (UK, US, Australia) in Israel and understood widely as second language there. French is taught and used in many government facilities and media in Lebanon, and is taught in some primary and secondary schools of Egypt and Syria. Maltese, a Semitic language mainly spoken in Europe, is used by the Franco-Maltese diaspora in Egypt. Due to widespread immigration of French Jews to Israel, it is the native language of approximately 200,000 Jews in Israel. Armenian speakers are to be found in the region. Georgian is spoken by the Georgian diaspora. Russian is spoken by a large portion of the Israeli population, because of emigration in the late 1990s. Russian today is a popular unofficial language in use in Israel; news, radio and sign boards can be found in Russian around the country after Hebrew and Arabic. Circassian is also spoken by the diaspora in the region and by almost all Circassians in Israel who speak Hebrew and English as well. The largest Romanian-speaking community in the Middle East is found in Israel, where as of 1995[update] Romanian is spoken by 5% of the population.[d] Bengali, Hindi and Urdu are widely spoken by migrant communities in many Middle Eastern countries, such as Saudi Arabia (where 20–25% of the population is South Asian), the United Arab Emirates (where 50–55% of the population is South Asian), and Qatar, which have large numbers of Pakistani, Bangladeshi and Indian immigrants. Culture The Middle East has recently become more prominent in hosting global sport events due to its wealth and desire to diversify its economy. The South Asian diaspora is a major backer of cricket in the region. See also Notes References Further reading External links 29°N 41°E / 29°N 41°E / 29; 41 |
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[SOURCE: https://en.wikipedia.org/wiki/Reserve_duty_(Israel)] | [TOKENS: 1660] |
Contents Reserve duty (Israel) In reserve duty (or reserve service; Hebrew: שירות מילואים, Sherut Milu'im), Israeli residents who have completed military service are assigned to the Israel Defense Forces' military reserve force to provide reinforcements during emergencies (war, military operations or natural disasters), and as a matter of routine course (e.g. for training, ongoing security and other activities). Some reservists are assigned to the same units they served in during their regular military service, and some are assigned to dedicated reserve units. Within the IDF's Personnel Directorate, the professional officer in charge of the reserve army is the Commander of Reserve Forces Corps (abbreviated קמל"ר; "Kamlar"), an officer with the rank of Brigadier General. For many years, reserve service had been implemented under the "Defense Service Law", but since 1 August 2008 it has been implemented mainly under the "Reserve Service Law". From 2004 onwards Israel has marked "Yom Miluim" ([National] Reserve Day) on the Lag BaOmer holiday to promote public sympathy for and appreciation of the soldiers serving in the reserve forces. Mandatory reserve service in Israel Reserve service is mandatory in Israel, and is considered part of the national ethos. The actual percentage serving in the IDF reserves has significantly dwindled over the years, and nowadays consists mainly of soldiers who served in one of the IDF combat units during their initial compulsory service. All Israelis under the age of 40 who served in the IDF, unless otherwise exempt, are theoretically eligible for reserve duty. Women in non-combat positions are released from this obligation upon the birth of their first child. However, only those who completed at least 20 days of reserve service in the past three years are considered to be active reservists. In 2015, about 26% of the population eligible for reserve duty had an active reservist status. In the past, the age of exemption from reserve duty by the Defense Service Law (חוק שירות ביטחון [נוסח משולב], התשמ"ו-1986) was 54 for men and 38 for women; nevertheless, it was not possible to call up reservists over 41 years of age who had served in a combat unit in the last 10 years or more, or reserve soldiers over the age of 48 who had served in a combat unit for at least 20 years, unless they gave consent for this to happen. Over the years, the IDF has lowered the maximum age at which male reservists are called for reserve duty service, so that the earliest age of exemption for males has become 40 for regular soldiers, 42 for combat officers, 45 for non-combat officers, 48 for soldiers serving in the Regional Defense units (הגמ"ר) and in non-military reservist units, and 51 years-of-age for the reservists serving as physicians in their reserve duty. In 2008 the Knesset approved the Reserve Service Law (חוק שירות המילואים, התשס"ח-2008) which came into effect on 1 August 2008. Accordingly, the age of exemption from reserve duty was reduced for all males, and as a result, ever since then it has stood at 40 for all soldiers, 45 for officers, and 49 for reservists who perform certain specific duties defined as such by the Minister of Defense and approved by the Foreign Affairs and Defense Committee (this mostly includes officials in the medical branch, drivers of heavy equipment, mechanics and technicians). Although still available for call-up in times of crisis, most men and virtually all women are not called up for reserve duty in any given year, as units do not always call up their reservists every year, and a variety of exemptions are available for regular reserve service, though virtually no exemptions exist for reserve duty in a time of crisis. The quota of the total reserve days per soldier is also determined in the Defense Service Law, and is defined as being 36 days per year, which the Israeli Minister of Defense has the authority to extend by a further seven days if necessary (and in special cases which are also defined in the law they might extend this period yet further for reservists who hold specific jobs and professions). The IDF calls its reservists for duty through a special call-up letter (צו קריאה) containing details of the reserve duty they are obliged to undertake, including the relevant dates and location. In cases where these dates might conflict with the work or school schedule of the reservist, they are allowed to appeal to the Reserve Coordination Committee (ולת"ם) who may grant a change to a more convenient time. In addition to calling up candidates for reserve duty involving training, preparation, and operational employment, the IDF might also call up reservists for duty in circumstances of emergency, via a special immediate order called "Decree 8" (צו 8). Since 2001 reserve duty is also performed in the Israel Border Police units. Reserve service also applies for units of the Office of the Prime Minister, such as the Shin Bet and the Mossad. Until the mid-1990s female reservists were very rare in the IDF. Nevertheless, with the opening of many military professions to women, many female soldiers were required to agree to take part in reserve duty after they finish their initial mandatory service in the military as a condition for joining certain positions in the IDF. Women serve until fully exempt from service at age 40, regardless of marital status. Pregnant women, or those with children are given immediate exemption from service, unless they serve in combat roles. The reserve duty in the Israeli ethos and in Israeli popular culture In the first four decades following the establishment of the State of Israel, a large part of the Israeli population served in the IDF reserves, and the amount of reserve duty given to each one was relatively high (in most instances one month per year, and sometimes even up to two months per year). As a result, a rich folklore developed surrounding the Israeli reserve service in which the IDF reservist was portrayed as a kind soldier, a little lazy, but with a sense of humour, ingenuity and resourcefulness, who served his country from ideological motives. One of the most prominent Israeli films depicting the reserve service experience is Assi Dayan's 1976 cult comedy Giv'at Halfon Eina Ona. The film depicts the comic situations resulting from the encounter between the reservists' everyday civilian life, and the rigid world of the military. In the mid-2000s the TV series Miluim depicted the experiences of the members of a reserve unit called up for service, taking the viewer through their training, strategy, teamwork, and different missions. A notable feature of Israeli songs dealing with the reserve duty experience is the deeply humorous tone intertwined in describing this way of life. One of the most famous of these songs is "Pgisha BaMiluim" (פגישה במילואים) by Israeli pop group The High Windows, which gained massive and immediate popularity in Israel upon its release in the 1960s. The prominent Israeli comedy group HaGashash HaHiver also had various skits which focused on the experience of reserve duty in the IDF. One of the most famous of these, "The Drafted Vehicle", portrayed the experiences of three IDF reservists after the Six-Day War, who are in charge of stowing various cars commandeered by the military during the war. Other such famous sketches include "Cooks Discourse", in which two veteran reservist cooks meet and reminisce about the period of the establishment of the State of Israel, together with a non-reserve IDF soldier; and "Pagaz Compote" in which a reservist seeks to be exempted from his upcoming duty because he is getting married. External links Media related to Reserve forces of Israel at Wikimedia Commons References |
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[SOURCE: https://en.wikipedia.org/wiki/Terrorist] | [TOKENS: 9874] |
Contents Terrorism Terrorism, in its broadest sense, is the use of violence against non-combatants to achieve political or ideological aims. The term is used in this regard primarily to refer to intentional violence during peacetime or in the context of war against non-combatants. There are various different definitions of terrorism, with no universal agreement about it. Different definitions of terrorism emphasize its randomness, its aim to instill fear, and its broader impact beyond its immediate victims. Modern terrorism, evolving from earlier iterations, employs various tactics to pursue political goals, often leveraging fear as a strategic tool to influence decision makers. By targeting densely populated public areas such as transportation hubs, airports, shopping centers, tourist attractions, and nightlife venues, terrorists aim to instill widespread insecurity, prompting policy changes through psychological manipulation and undermining confidence in security measures. The terms "terrorist" and "terrorism" originated during the French Revolution of the late 18th century, but became widely used internationally and gained worldwide attention in the 1970s during the Troubles in Northern Ireland, the Basque conflict and the Israeli–Palestinian conflict. The increased use of suicide attacks from the 1980s onwards was typified by the September 11 attacks in the United States in 2001. The Global Terrorism Database, maintained by the University of Maryland, College Park, has recorded more than 61,000 incidents of non-state terrorism, resulting in at least 140,000 deaths between 2000 and 2014. Various organizations and countries have used terrorism to achieve their objectives. These include left-wing and right-wing political organizations, nationalist groups, religious groups, revolutionaries, and ruling governments. In recent decades, hybrid terrorist organizations have emerged, incorporating both military and political arms. State terrorism, with its institutionalized instrumentation of terror tactics through massacres, genocides, forced disappearances, carpet bombings and torture, is a deadlier form of terrorism than non-state terrorism. Etymology and definition The term "terrorism" itself was originally used to describe the actions of the Jacobin Club during the "Reign of Terror" in the French Revolution. "Terror is nothing other than justice, prompt, severe, inflexible", said Jacobin leader Maximilien Robespierre. In 1795, Edmund Burke denounced the Jacobins for letting "thousands of those hell-hounds called Terrorists ... loose on the people" of France. John Calvin's rule over Geneva in the 16th century has also been described as a reign of terror. The terms "terrorism" and "terrorist" gained renewed currency in the 1970s as a result of the Palestine Liberation Organization (PLO), the Irish Republican Army (IRA), the Basque separatist group, ETA, and the operations of groups such as the Red Army Faction. Leila Khaled was described as a terrorist in a 1970 issue of Life magazine. A number of books on terrorism were published in the 1970s. The topic came further to the fore after the 1983 Beirut barracks bombings and again after the 2001 September 11 attacks and the 2002 Bali bombings. No definition of terrorism has gained universal agreement. Challenges emerge due to the politically and emotionally charged nature of the term, the double standards used in applying it, and disagreement over the nature of terrorist acts and limits of the right to self-determination. Harvard law professor Richard Baxter, a leading expert on the law of war, was a skeptic: "We have cause to regret that a legal concept of 'terrorism' was ever inflicted upon us. The term is imprecise; it is ambiguous; and above all, it serves no operative legal purpose." Different legal systems and government agencies employ diverse definitions of terrorism, with governments showing hesitation in establishing a universally accepted, legally binding definition. Title 18 of the United States Code §2331, part of Chapter 113B, defines terrorism as acts that are intended to (1) intimidate or coerce civilians, (2) influence government policy by coercion, or (3) to affect the conduct of a government by mass destruction, assassination, or kidnapping. The international community has been slow to formulate a universally agreed, legally binding definition of this crime, and has been unable to conclude a Comprehensive Convention on International Terrorism that incorporates a single, all-encompassing, legally binding, criminal law definition of terrorism. These difficulties arise from the fact that the term "terrorism" is politically and emotionally charged. The international community has instead adopted a series of sectoral conventions, which do not have terrorism as a single cohesive criminal offense of terrorism. Rather sectoral conventions criminalizes various types of criminal activities involved in the commission of terrorism (for example homicide). Counterterrorism analyst Bruce Hoffman has noted that it is not only individual agencies within the same governmental apparatus that cannot agree on a single definition of terrorism; experts and other long-established scholars in the field are equally incapable of reaching a consensus. In 1992, terrorism studies scholar Alex P. Schmid proposed a simple definition to the United Nations Commission on Crime Prevention and Criminal Justice (CCPCJ) as "peacetime equivalents of war crimes", but it was not accepted. In 2006, it was estimated that there were over 109 different definitions of terrorism. History Early published studies like Paul Wilkinson considered terrorism a product of 19th-century revolutionary politics. Technological developments like the pistol and dynamite made possible the relentless onslaught of successful attacks and assassinations that shook the 19th-century. For the most part, scholars considered terrorism a modern phenomenon until David C. Rapoport published his seminal article Fear and Trembling: Terrorism in Three Religious Traditions in 1984. Rapoport proposed three case studies to demonstrate "ancient lineage" of religious terrorism, which he called "sacred terror": the "Thugs", the Assassins and the Jewish Sicarii Zealots. Rapoport argued religious terrorism has been ongoing since ancient times and that "there are signs that it is reviving in new and unusual forms". He is the first to propose that religious doctrines were more important than political rationales for some terrorist groups. Rapoport's work has since become the basis of the model of "New Terrorism" proposed by Bruce Hoffman and developed by other scholars. "New Terrorism" has had an unparalleled impact on policymaking. Critics have pointed out that the model is politically charged and over-simplified. The underlying historical assertions have received less critical attention. According to The Oxford Handbook on the History of Terrorism: Since the publication of Rapoport's article, it has become seemingly pre-requisite for standard works on terrorism to cite the three case studies and to reproduce uncritically its findings. In lieu of empirical research, authors tend to crudely paraphrase Rapoport and the assumed relevance of "Thuggee" to the study of modern terrorism is taken for granted. Yet the significance of the article is not simply a matter of citations―it has also provided the foundation for what has become known as the "New Terrorism" paradigm. While Rapoport did not suggest which late 20th century groups might exemplify the implied recurrence of "holy terror", Bruce Hoffman, recognized today as one of the world's leading terrorism experts, did not hesitate to do so. A decade after Rapoport's article. Hoffman picked up the mantle and taking the three case studies as inspiration, he formulated a model of contemporary "holy terror" or, as he defined it, "terrorism motivated by a religious imperative". Completely distinct from "secular terrorists", Hoffman argued that "religious terrorists" carry out indiscriminate acts of violence as a divine duty with no consideration for political efficacy―their aim is transcendental and "holy terror" constitutes an end in itself. Hoffman's concept has since been taken up and developed by a number of other writers, including Walter Laquer, Steven Simon and Daniel Benjamen, and rebranded as the "New Terrorism". Arguably, the first organization to use modern terrorist techniques was the Irish Republican Brotherhood, founded in 1858 as a revolutionary Irish nationalist group that carried out attacks in England. The group initiated the Fenian dynamite campaign in 1881, one of the first modern terror campaigns. Instead of earlier forms of terrorism based on political assassination, this campaign used timed explosives with the express aim of sowing fear in the very heart of metropolitan Britain, in order to achieve political gains. Another early terrorist-type group was Narodnaya Volya, founded in Russia in 1878 as a revolutionary anarchist group inspired by Sergei Nechayev and "propaganda by the deed" theorist Carlo Pisacane. The group developed ideas—such as targeted killing of the 'leaders of oppression', which were to become the hallmark of subsequent violence by small non-state groups, and they were convinced that the developing technologies of the age—such as the invention of dynamite, which they were the first anarchist group to make widespread use of—enabled them to strike directly and with discrimination. In the Western world, and more specifically in France, the repression faced by anarchists from the state led, in the early 1890s, to France's entry into the Ère des attentats (1892–1894). This period, characterized by a surge in terrorist acts following Ravachol's bombings, saw several shifts that pushed terrorism toward modern terrorism. As with the Fenian campaign, terrorism shifted from being person-based to location-based, starting with the first attack of that period, the Saint-Germain bombing. However, other major evolutions emerged during this period: the apparition of lone wolves and the birth of mass or indiscriminate terrorism. Indeed, in the second half of the Ère des attentats, three incidents laid the foundation for mass terrorism within a few months of each other. These were the Liceu bombing, the 13 November 1893 stabbing, and the Café Terminus attack. In each of these attacks, the perpetrators targeted not a specific individual but a collective enemy. Émile Henry, in particular, responsible for the Café Terminus bombing, explicitly claimed the birth of this new form of terrorism, stating that he wanted to 'strike at random'. In 1920 Leon Trotsky wrote Terrorism and Communism to justify the Red Terror and defend the moral superiority of revolutionary terrorism. The assassination of the Empress of Austria Elisabeth in 1898 resulted in the International Conference of Rome for the Social Defense Against Anarchists, the first international conference against terrorism. According to Bruce Hoffman of the RAND Corporation, in 1980, 2 out of 64 terrorist groups were categorized as having religious motivation while in 1995, almost half (26 out of 56) were religiously motivated with the majority having Islam as their guiding force. Types of terrorism Depending on the country, the political system, and the time in history, the types of terrorism are varying. In early 1975, the Law Enforcement Assistant Administration in the United States formed the National Advisory Committee on Criminal Justice Standards and Goals. One of the five volumes that the committee wrote was titled Disorders and Terrorism, produced by the Task Force on Disorders and Terrorism under the direction of H. H. A. Cooper, Director of the Task Force staff. The Task Force defines terrorism as "a tactic or technique by means of which a violent act or the threat thereof is used for the prime purpose of creating overwhelming fear for coercive purposes". It classified disorders and terrorism into seven categories: Other sources have defined the typology of terrorism in different ways, for example, broadly classifying it into domestic terrorism and international terrorism, or using categories such as vigilante terrorism or insurgent terrorism. Some ways the typology of terrorism may be defined are: According to Ibn Abbas and some Islamic scholars, a person who kills another remains in eternal hellfire. A Muslim cannot kill even to enter paradise. Terrorism cannot be reconciled with Islam. It is impossible to consider a terrorist a Muslim. It is impossible to allow for terrorism in Islam. Killing for God's pleasure is inexplicable. Terrorism is inexplicable. There is no terrorism in Islam. A Muslim cannot be a terrorist. No terrorist is a Muslim. In Islam, killing is equated with blaspheming God or denying Him. Fethullah Gülen stated that "acts such as becoming suicide bombers in the name of doing something for Allah—by those pretending to be Muslims—entering crowds of innocents and exploding, loading bombs into cars and driving into unaware, innocent people, and especially destroying places of worship, cannot be reconciled with either the Quran or the Sunnah. What cannot be reconciled with the Quran and Sunnah cannot be reconciled with Islam either." "Yes, no matter what justification one uses to resort to terrorism and violence, they are in grave error. The claims of radical terrorist organizations—whether asserting a struggle for independence, seeking to reclaim rights taken from them, or intending to punish injustices done to them—cannot legitimize acts of terror and violence." According to Fethullah Gülen, a Muslim cannot be a terrorist; because Islam prescribes the severest punishment in this world for endangering human life and security; in the Hereafter, alongside denying God and associating partners with Him, it assigns the severest punishment to killing a human being, threatening that those who intentionally take life will remain in Hell eternally. A person bearing the qualities of Islam cannot commit an act for which such a punishment is prescribed. Therefore, neither can a terrorist be a true Muslim, nor can a Muslim be a terrorist. According to the Global Terrorism Index by the University of Maryland, College Park, religious extremism has overtaken national separatism and become the main driver of terrorist attacks around the world. Since 9/11 there has been a five-fold increase in deaths from terrorist attacks. The majority of incidents over the past several years can be tied to groups with a religious agenda. Before 2000, it was nationalist separatist terrorist organizations such as the IRA and Chechen rebels who were behind the most attacks. The number of incidents from nationalist separatist groups has remained relatively stable in the years since while religious extremism has grown. The prevalence of Islamist groups in Iraq, Afghanistan, Pakistan, Nigeria and Syria is the main driver behind these trends. Hamas, the main Islamist movement in the Palestinian territories, was formed by Palestinian imam Ahmed Yassin in 1987. Some scholars, including constitutional law professor Alexander Tsesis, have voiced concerns over the Hamas Charter's apparent advocacy of genocidal aspirations. In the periods of 1994–1996 and 2001–2007, Hamas orchestrated a series of suicide bombings, primarily directed at civilian targets in Israel, killing over 1,000 Israeli civilians. Four of the terrorist groups that have been most active since 2001 are Boko Haram, al-Qaeda, the Taliban and ISIL. These groups have been most active in Iraq, Afghanistan, Pakistan, Nigeria and Syria. In 2013 eighty percent of all deaths from terrorism occurred in these five countries. In 2015 four Islamic extremist groups were responsible for 74% of all deaths from Islamic terrorism: ISIS, Boko Haram, the Taliban, and al-Qaeda, according to the Global Terrorism Index 2016. Since approximately 2000, these incidents have occurred on a global scale, affecting not only Muslim-majority states in Africa and Asia, but also states with non-Muslim majority such as United States, United Kingdom, France, Germany, Spain, Belgium, Sweden, Russia, Australia, Canada, Sri Lanka, Israel, China, India and Philippines. Such attacks have targeted both Muslims and non-Muslims, however the majority affect Muslims themselves. Terrorism in Pakistan has become a great problem. From the summer of 2007 until late 2009, more than 1,500 people were killed in suicide and other attacks on civilians for reasons attributed to a number of causes—sectarian violence between Sunni and Shia Muslims; easy availability of guns and explosives; the existence of a "Kalashnikov culture"; an influx of ideologically driven Muslims based in or near Pakistan, who originated from various nations around the world and the subsequent war against the pro-Soviet Afghans in the 1980s which blew back into Pakistan; the presence of Islamist insurgent groups and forces such as the Taliban and Lashkar-e-Taiba. On July 2, 2013, in Lahore, 50 Muslim scholars of the Sunni Ittehad Council (SIC) issued a collective fatwa against suicide bombings, the killing of innocent people, bomb attacks, and targeted killings declaring them as Haraam or forbidden. In 2015, the Southern Poverty Law Center released a report on domestic terrorism in the United States. The report (titled The Age of the Wolf) analyzed 62 incidents and found that, between 2009 and 2015, "more people have been killed in America by non-Islamic domestic terrorists than jihadists." The "virulent racist and antisemitic" ideology of the ultra-right wing Christian Identity movement is usually accompanied by anti-government sentiments. Adherents of Christian Identity are not connected with specific Christian denominations, and they believe that whites of European descent can be traced back to the "Lost Tribes of Israel". Adherents have committed hate crimes, bombings and other acts of terrorism, including the Centennial Olympic Park bombing. Its influence ranges from the Ku Klux Klan and neo-Nazi groups to the anti-government militia and sovereign citizen movements. Causes and motivations Terrorist acts frequently have a political purpose based on self-determination claims, ethnonationalist frustrations, single issue causes (like abortion or the environment), or other ideological or religious causes that terrorists claim are a moral justification for their violent acts. Individuals and groups choose terrorism as a tactic because it can: Attacks on "collaborators" are used to intimidate people from cooperating with the state in order to undermine state control. This strategy was used in Ireland, in Kenya, in Algeria and in Cyprus during their independence struggles. Stated motives for the September 11 attacks included inspiring more fighters to join the cause of repelling the United States from Muslim countries with a successful high-profile attack. The attacks prompted some criticism from domestic and international observers regarding perceived injustices in U.S. foreign policy that provoked the attacks, but the larger practical effect was that the United States government declared a war on terror that resulted in substantial military engagements in several Muslim-majority countries. Various commentators have inferred that al-Qaeda expected a military response and welcomed it as a provocation that would result in more Muslims fighting the United States. Some commentators believe that the resulting anger and suspicion directed toward innocent Muslims living in Western countries and the indignities inflicted upon them by security forces and the general public also contributes to radicalization of new recruits. Despite criticism that the Iraqi government had no involvement with the September 11 attacks, Bush declared the 2003 invasion of Iraq to be part of the war on terror. The resulting backlash and instability enabled the rise of Islamic State of Iraq and the Levant and the temporary creation of an Islamic caliphate holding territory in Iraq and Syria, until ISIL lost its territory through military defeats. Attacks used to draw international attention to struggles that are otherwise unreported have included the Palestinian airplane hijackings in 1970 and the 1975 Dutch train hostage crisis. Specific political or social causes have included: Causes for right-wing terrorism have included white nationalism, ethnonationalism, fascism, anti-socialism, the anti-abortion movement, and tax resistance. Sometimes terrorists on the same side fight for different reasons. For example, in the Chechen–Russian conflict secular Chechens using terrorist tactics fighting for national independence are allied with radical Islamist terrorists who have arrived from other countries. Various personal and social factors may influence the personal choice of whether to join a terrorist group or attempt an act of terror, including: A report conducted by Paul Gill, John Horgan and Paige Deckert [dubious – discuss] found that for "lone wolf" terrorists: Ariel Merari, a psychologist who has studied the psychological profiles of suicide terrorists since 1983 through media reports that contained biographical details, interviews with the suicides' families, and interviews with jailed would-be suicide attackers, concluded that they were unlikely to be psychologically abnormal. In comparison to economic theories of criminal behaviour, Scott Atran found that suicide terrorists exhibit none of the socially dysfunctional attributes—such as fatherless, friendless, jobless situations—or suicidal symptoms. By which he means, they do not kill themselves simply out of hopelessness or a sense of 'having nothing to lose'. Abrahm suggests that terrorist organizations do not select terrorism for its political effectiveness. Individual terrorists tend to be motivated more by a desire for social solidarity with other members of their organization than by political platforms or strategic objectives, which are often murky and undefined. Michael Mousseau shows possible relationships between the type of economy within a country and ideology associated with terrorism.[example needed] Many terrorists have a history of domestic violence. Democracy and domestic terrorism Terrorism is most common in nations with intermediate political freedom, and it is least common in the most democratic nations. Some examples of terrorism in non-democratic nations include ETA in Spain under Francisco Franco (although the group's activities increased sharply after Franco's death), the Organization of Ukrainian Nationalists in pre-war Poland, the Shining Path in Peru under Alberto Fujimori, the Kurdistan Workers Party when Turkey was ruled by military leaders, and the ANC in South Africa. According to Boaz Ganor, "Modern terrorism sees the liberal democratic state, in all its variations, as the perfect launching pad and a target for its attacks. Moreover, some terrorist organizations—particularly Islamist-jihadist organizations—have chosen to cynically exploit democratic values and institutions to gain power and status, promote their interests, and achieve internal and international legitimacy". Jihadist militants have shown an ambivalent view towards democracy, as they both exploit it for their ends and oppose it in their ideology. Various quotes from jihadist leaders note their disdain for democracy and their efforts to undermine it in favor of Islamic rule. Democracies, such as Japan, the United Kingdom, the United States, Israel, Indonesia, India, Spain, Germany, Italy and the Philippines, have all experienced domestic terrorism. While a democratic nation espousing civil liberties may claim a sense of higher moral ground than other regimes, an act of terrorism within such a state may cause a dilemma: whether to maintain its civil liberties and thus risk being perceived as ineffective in dealing with the problem; or alternatively to restrict its civil liberties and thus risk delegitimizing its claim of supporting civil liberties. For this reason, homegrown terrorism has started to be seen as a greater threat, as stated by former CIA Director Michael Hayden. This dilemma, some social theorists would conclude, may very well play into the initial plans of the acting terrorist(s); namely, to delegitimize the state and cause a systematic shift towards anarchy via the accumulation of negative sentiments towards the state system. Perpetrators The perpetrators of acts of terrorism can be individuals, groups, or states. According to some definitions, clandestine or semi-clandestine state actors may carry out terrorist acts outside the framework of a state of war. The most common image of terrorism is that it is carried out by small and secretive cells, highly motivated to serve a particular cause and many of the most deadly operations in recent times, such as the September 11 attacks, the London underground bombing, 2008 Mumbai attacks, the 2014 Peshawar school massacre and the 2002 Bali bombings were planned and carried out by a close clique, composed of close friends, family members and other strong social networks. These groups benefited from the free flow of information and efficient telecommunications to succeed where others had failed. Over the years, much research has been conducted to distill a terrorist profile to explain these individuals' actions through their psychology and socio-economic circumstances. Some specialists highlight the lack of evidence supporting the idea that terrorists are typically psychologically disturbed. The careful planning and detailed execution seen in many terrorist acts are not characteristics generally associated with mentally unstable individuals. Others, like Roderick Hindery, have sought to discern profiles in the propaganda tactics used by terrorists. Some security organizations designate these groups as violent non-state actors.[citation needed] A 2007 study by economist Alan B. Krueger found that terrorists were less likely to come from an impoverished background (28 percent versus 33 percent) and more likely to have at least a high-school education (47 percent versus 38 percent). Another analysis found only 16 percent of terrorists came from impoverished families, versus 30 percent of male Palestinians, and over 60 percent had gone beyond high school, versus 15 percent of the populace. To avoid detection, a terrorist will look, dress, and behave normally until executing the assigned mission. Some claim that attempts to profile terrorists based on personality, physical, or sociological traits are not useful. The physical and behavioral description of the terrorist could describe almost any normal person. The majority of terrorist attacks are carried out by military age men, aged 16 to 40. Groups not part of the state apparatus of in opposition to the state are most commonly referred to as a "terrorist" in the media. According to the Global Terrorism Database, the most active terrorist group in the period 1970 to 2010 was Shining Path (with 4,517 attacks), followed by Farabundo Marti National Liberation Front (FMLN), Irish Republican Army (IRA), Basque Fatherland and Freedom (ETA), Revolutionary Armed Forces of Colombia (FARC), Taliban, Liberation Tigers of Tamil Eelam, New People's Army, National Liberation Army of Colombia (ELN), and Kurdistan Workers Party (PKK). Israel has had problems with religious terrorism even before independence in 1948. During British mandate over Palestine, the secular Irgun were among the Zionist groups labelled as terrorist organisations by the British authorities and United Nations, for violent terror attacks against Britons and Arabs. Another extremist group, the Lehi, openly declared its members as "terrorists". Historian William Cleveland stated many Jews justified any action, even terrorism, taken in the cause of the creation of a Jewish state. In 1995, Yigal Amir assassinated Israeli Prime Minister Yitzhak Rabin. For Amir, killing Rabin was an exemplary act that symbolized the fight against an illegitimate government that was prepared to cede Jewish Holy Land to the Palestinians. Members of Kach, a Jewish ultranationalist party, employed terrorist tactics in pursuit of what they viewed as religious imperatives. Israel and a few other countries have designated the party as a terrorist group. State sponsors have constituted a major form of funding; for example, Palestine Liberation Organization, Democratic Front for the Liberation of Palestine and other groups sometimes considered to be terrorist organizations, were funded by the Soviet Union. Iran has provided funds, training, and weapons to organizations such as Lebanese Shi’ite group Hezbollah, the Yemenite Houthi movement, and Palestinian factions such as Hamas and Islamic Jihad. Iranian funding for Hamas is estimated to reach several hundred million dollars annually. These groups and others have played significant roles in Iran's foreign policy and served as proxies in conflicts. The Stern Gang received funding from Italian Fascist officers in Beirut to undermine the British authorities in Palestine. "Revolutionary tax" is another major form of funding, and essentially a euphemism for "protection money". Revolutionary taxes "play a secondary role as one other means of intimidating the target population". Other major sources of funding include kidnapping for ransoms, smuggling (including wildlife smuggling), fraud, and robbery. The Islamic State in Iraq and the Levant has reportedly received funding "via private donations from the Gulf states". Irish Republican militants, primarily the Provisional Irish Republican Army and the Irish National Liberation Army, and Loyalist paramilitaries, primarily the Ulster Volunteer Force and Ulster Defence Association, received far more financing from criminal and legitimate activities within the British Isles than overseas donations, including Libyan dictator Muammar Gaddafi and NORAID (see Paramilitary finances in the Troubles for more information). The Financial Action Task Force is an inter-governmental body whose mandate, since October 2001, has included combating terrorist financing. Tactics Terrorist attacks are often targeted to maximize fear and publicity, most frequently using explosives. Terrorist groups usually methodically plan attacks in advance, and may train participants, plant undercover agents, and raise money from supporters or through organized crime. Communications occur through modern telecommunications, or through old-fashioned methods such as couriers. There is concern about terrorist attacks employing weapons of mass destruction. Some academics have argued that while it is often assumed terrorism is intended to spread fear, this is not necessarily true, with fear instead being a by-product of the terrorist's actions, while their intentions may be to avenge fallen comrades or destroy their perceived enemies. Terrorism is a form of asymmetric warfare and is more common when direct conventional warfare will not be effective because opposing forces vary greatly in power. Yuval Harari argues that the peacefulness of modern states makes them paradoxically more vulnerable to terrorism than pre-modern states. Harari argues that because modern states have committed themselves to reducing political violence to almost zero, terrorists can, by creating political violence, threaten the very foundations of the legitimacy of the modern state. This is in contrast to pre-modern states, where violence was a routine and recognised aspect of politics at all levels, making political violence unremarkable. Terrorism thus shocks the population of a modern state far more than a pre-modern one and consequently the state is forced to overreact in an excessive, costly and spectacular manner, which is often what the terrorists desire. The type of people terrorists will target is dependent upon the ideology of the terrorists. A terrorist's ideology will create a class of "legitimate targets" who are deemed as its enemies and who are permitted to be targeted. This ideology will also allow the terrorists to place the blame on the victim, who is viewed as being responsible for the violence in the first place. Stabbing attacks, a historical tactic, have reemerged as a prevalent form of terrorism in the 21st century, notably during the 2010s and 2020s. This resurgence originated with the GIA in the 1990s and later expanded among Palestinian terrorists and Islamic State militants. The trend gained momentum with a wave of "lone wolf" terrorist stabbing attacks by Palestinians targeting Israelis beginning in 2015. Subsequently, this pattern extended to Europe during the surge of Islamic terrorism in the 2010s, witnessing "at least" 10 stabbing attacks allegedly motivated by Islamic extremism by the spring of 2017, with France experiencing a notable concentration of such incidents. Terrorists may attempt to use the media to spread their message or manipulate their target audience. Shamil Basayev used this tactic during the Budyonnovsk hospital hostage crisis and again in the Moscow theater hostage crisis. Terrorists may also target national symbols for attention. Walter Lacquer wrote that "terrorism was always, to a large extent, about public relations and propaganda ('Propaganda by Deed' had been the slogan in the nineteenth century)". The El Al Flight 426 hijacking is considered a turning point for modern terrorism studies. The Popular Front for the Liberation of Palestine (PFLP) realized they could combine the tactics of targeting national symbols and civilians (in this case as hostages) to generate a mass media spectacle. Zehdi Labib Terzi made a public statement about this in 1976: "The first several hijackings aroused the consciousness of the world and awakened the media and world opinion much more ― and more effectively ― than 20 years of pleading at the United Nations". Mass media exposure may be a primary goal of those carrying out terrorism, to expose issues that would otherwise be ignored by the media. Some consider this to be manipulation and exploitation of the media. The Internet has created a new way for groups to spread their messages. This has created a cycle of measures and counter measures by groups in support of and in opposition to terrorist movements. The United Nations has created its own online counterterrorism resource. The mass media will, on occasion, censor organizations involved in terrorism (through self-restraint or regulation) to discourage further terrorism. This may encourage organizations to perform more extreme acts of terrorism to be shown in the mass media. Conversely James F. Pastor explains the significant relationship between terrorism and the media, and the underlying benefit each receives from the other: There is always a point at which the terrorist ceases to manipulate the media gestalt. A point at which the violence may well escalate, but beyond which the terrorist has become symptomatic of the media gestalt itself. Terrorism as we ordinarily understand it is innately media-related. — Novelist William Gibson, 2004 Former British Prime Minister Margaret Thatcher famously spoke of the close connection between terrorism and the media, calling publicity 'the oxygen of terrorism'. The connection between terrorism and tourism has been widely studied since the 1997 Luxor massacre, during which 62 people, including 58 foreign nationals, were killed by Islamist group al-Jama'a al-Islamiyya in an archaeological site in Egypt. In the 1970s, the targets of terrorists were politicians and chiefs of police while now, international tourists and visitors are selected as the main targets of attacks.[citation needed] The attacks on the World Trade Center and the Pentagon on September 11, 2001, were the symbolic center, which marked a new epoch in the use of civil transport against the main power of the planet. From this event onwards, the spaces of leisure that characterized the pride of West were conceived as dangerous and frightful. Counterterrorism strategies Responses to terrorism are broad in scope. They can include re-alignments of the political spectrum and reassessments of fundamental values. Specific types of responses include: Terrorism research, also called terrorism studies, or terrorism and counter-terrorism research, is an academic field which seeks to understand the causes of terrorism, how to prevent it, as well as its impact in the broadest sense. Terrorism research can be carried out in both military and civilian contexts, for example by research centres such as the British Centre for the Study of Terrorism and Political Violence, the Norwegian Centre for Violence and Traumatic Stress Studies, and the International Centre for Counter-Terrorism (ICCT). There are several academic journals devoted to the field, including Perspectives on Terrorism. One of the agreements that promote the international legal counterterrorist framework is the Code of Conduct Towards Achieving a World Free of Terrorism that was adopted at the 73rd session of the United Nations General Assembly in 2018. The Code of Conduct was initiated by Kazakhstan President Nursultan Nazarbayev. Its main goal is to implement a wide range of international commitments to counterterrorism and establish a broad global coalition towards achieving a world free of terrorism by 2045. The Code was signed by more than 70 countries. According to a report by Dana Priest and William M. Arkin in The Washington Post, "Some 1,271 government organizations and 1,931 private companies work on programs related to counterterrorism, homeland security and intelligence in about 10,000 locations across the United States." America's thinking on how to defeat radical Islamists is split along two very different schools of thought. Republicans, typically follow what is known as the Bush Doctrine, advocate the military model of taking the fight to the enemy and seeking to democratize the Middle East. Democrats, by contrast, generally propose the law enforcement model of better cooperation with nations and more security at home. In the introduction of the U.S. Army / Marine Corps Counterinsurgency Field Manual, Sarah Sewall states the need for "U.S. forces to make securing the civilian, rather than destroying the enemy, their top priority. The civilian population is the center of gravity—the deciding factor in the struggle.... Civilian deaths create an extended family of enemies—new insurgent recruits or informants—and erode support of the host nation." Sewall sums up the book's key points on how to win this battle: "Sometimes, the more you protect your force, the less secure you may be.... Sometimes, the more force is used, the less effective it is.... The more successful the counterinsurgency is, the less force can be used and the more risk must be accepted.... Sometimes, doing nothing is the best reaction." This strategy, often termed "courageous restraint", has certainly led to some success on the Middle East battlefield. However, it does not address the fact that terrorists are mostly homegrown. Jones and Libicki (2008) created a list of all the terrorist groups they could find that were active between 1968 and 2006. They found 648. Of those, 136 splintered and 244 were still active in 2006. Of the ones that ended, 43% converted to nonviolent political actions, like the Irish Republican Army in Northern Ireland; 40% were defeated by law enforcement; 7% (20 groups) were defeated by military force; and 10% succeeded. 42 groups became large enough to be labeled an insurgency; 38 of those had ended by 2006. Of those, 47% converted to nonviolent political actors. Only 5% were ended by law enforcement, and 21% were defeated by military force. 26% won. Jones and Libicki concluded that military force may be necessary to deal with large insurgencies but are only occasionally decisive, because the military is too often seen as a bigger threat to civilians than the terrorists. To avoid that, the rules of engagement must be conscious of collateral damage and work to minimize it. When militant groups face violent competition from other groups, they often shift from high-profile attacks on civilians to more restrained tactics, a strategy of terrorist restraint that arises due to resource constraints and fear of civilian backlash. Another researcher, Audrey Cronin, lists six primary ways that terrorist groups end: State and state sponsored-terrorism Civilization is based on a clearly defined and widely accepted yet often unarticulated hierarchy. Violence done by those higher on the hierarchy to those lower is nearly always invisible, that is, unnoticed. When it is noticed, it is fully rationalized. Violence done by those lower on the hierarchy to those higher is unthinkable, and when it does occur it is regarded with shock, horror, and the fetishization of the victims. — Derrick Jensen As with "terrorism" the concept of "state terrorism" is controversial. The Chairman of the United Nations Counter-Terrorism Committee has stated that the committee was conscious of 12 international conventions on the subject, and none of them referred to state terrorism, which was not an international legal concept. If states abused their power, they should be judged against international conventions dealing with war crimes, international human rights law, and international humanitarian law. Former United Nations Secretary-General Kofi Annan has said that it is "time to set aside debates on so-called 'state terrorism'. The use of force by states is already thoroughly regulated under international law". He made clear that, "regardless of the differences between governments on the question of the definition of terrorism, what is clear and what we can all agree on is that any deliberate attack on innocent civilians [or non-combatants], regardless of one's cause, is unacceptable and fits into the definition of terrorism." State terrorism has been used to refer to terrorist acts committed by governmental agents or forces. This involves the use of state resources employed by a state's foreign policies, such as using its military to directly perform acts of terrorism. Professor of Political Science Michael Stohl cites the examples that include the German bombing of London, the Japanese surprise attack on Pearl Harbor, the Allied firebombing of Dresden, and the U.S. atomic bombings of Hiroshima and Nagasaki during World War II. He argues that "the use of terror tactics is common in international relations and the state has been and remains a more likely employer of terrorism within the international system than insurgents." He cites the first strike option as an example of the "terror of coercive diplomacy" as a form of this, which holds the world hostage with the implied threat of using nuclear weapons in "crisis management" and he argues that the institutionalized form of terrorism has occurred as a result of changes that took place following World War II. In this analysis, state terrorism exhibited as a form of foreign policy was shaped by the presence and use of weapons of mass destruction, and the legitimizing of such violent behavior led to an increasingly accepted form of this behavior by the state. Charles Stewart Parnell described William Ewart Gladstone's Irish Coercion Act as terrorism in his "no-Rent manifesto" in 1881, during the Irish Land War. The concept is used to describe political repressions by governments against their own civilian populations with the purpose of inciting fear. For example, taking and executing civilian hostages or extrajudicial elimination campaigns are commonly considered "terror" or terrorism, for example during the Red Terror or the Great Terror. Such actions are often described as democide or genocide, which have been argued to be equivalent to state terrorism. Empirical studies on this have found that democracies have little democide. Western democracies, including the United States, have supported state terrorism and mass killings, with some examples being the Indonesian mass killings of 1965–66 and Operation Condor. A state can sponsor terrorism by funding or harboring a terrorist group. Opinions as to which acts of violence by states consist of state-sponsored terrorism vary widely. When states provide funding for groups considered by some to be terrorist, they rarely acknowledge them as such. Impact and debate Terrorism is a charged term. It is often used with the connotation of something that is morally wrong. Governments and non-state groups use the term to abuse or denounce opposing groups. While legislation defining terrorism as a crime has been adopted in many states, the distinction between activism and terrorism remains a complex and debated matter. There is no consensus as to whether terrorism should be regarded as a war crime. State terrorism is that perpetrated by nation states, but is not considered such by the state conducting it, making legality a grey area. Countries sometimes opt to ignore terrorist activities committed by allies. The use of the term in the Israeli–Palestinian conflict has given rise to controversies concerning the vagueness of how terrorists are defined and identified. Media outlets who wish to convey impartiality may limit their usage of "terrorist" and "terrorism" because they are loosely defined, potentially controversial in nature, and subjective terms. The term "terrorism" is often used to abuse or denounce opposite parties, either governments or non-state groups. An example of this is the terruqueo political attack used by right-wing groups in Peru to target leftist groups or those opposed to the neoliberal status quo, likening opponents to guerrilla organizations from the internal conflict in Peru. Those labeled "terrorists" by their opponents rarely identify themselves as such, but it was not always so. While a multitude of terms like separatist, freedom fighter, liberator, revolutionary, vigilante, militant, paramilitary, guerrilla, rebel, patriot, have come into use, (including some culturally specific terms borrowed from other languages like Jihadi, mujahideen, and fedayeen), the unwillingness to self-identify as terrorists began when parties in a conflict started to describe each other as terrorists pejoratively. As an example, when Vera Zasulich attacked a Russian official known for abusing prisoners she told the court "I am not a criminal, I am a terrorist!". The stunned court acquitted Zazulich when they realized that she was trying to become a martyr. She was carried out of the courtroom on the shoulders of the crowd. Some groups and individuals have openly admitted to using "terrorist tactics" even while maintaining distance from the pejorative term in their self-descriptions. The Zionist militant group Lohamei Herut Yisrael admitted that they used terrorist tactics but used the euphemism "Freedom Fighters" to describe themselves (Lohamei Herut Yisrael means "Freedom Fighters for Israel".) In his book Inside Terrorism Bruce Hoffman offered an explanation of why the term terrorism becomes distorted: On one point, at least, everyone agrees: terrorism is a pejorative term. It is a word with intrinsically negative connotations that is generally applied to one's enemies and opponents, or to those with whom one disagrees and would otherwise prefer to ignore. 'What is called terrorism,' Brian Jenkins has written, 'thus seems to depend on one's point of view. Use of the term implies a moral judgment; and if one party can successfully attach the label terrorist to its opponent, then it has indirectly persuaded others to adopt its moral viewpoint.' Hence the decision to call someone or label some organization terrorist becomes almost unavoidably subjective, depending largely on whether one sympathizes with or opposes the person/group/cause concerned. If one identifies with the victim of the violence, for example, then the act is terrorism. If, however, one identifies with the perpetrator, the violent act is regarded in a more sympathetic, if not positive (or, at the worst, an ambivalent) light; and it is not terrorism. The pejorative connotations of the word can be summed up in the aphorism, "One man's terrorist is another man's freedom fighter". This is exemplified when a group using irregular military methods is an ally of a state against a mutual enemy, but later falls out with the state and starts to use those methods against its former ally. Groups accused of terrorism understandably prefer terms reflecting legitimate military or ideological action. Leading terrorism researcher Professor Martin Rudner, director of the Canadian Centre of Intelligence and Security Studies at Ottawa's Carleton University, defines "terrorist acts" as unlawful attacks for political or other ideological goals, and said: There is the famous statement: 'One man's terrorist is another man's freedom fighter.' But that is grossly misleading. It assesses the validity of the cause when terrorism is an act. One can have a perfectly beautiful cause and yet if one commits terrorist acts, it is terrorism regardless. Labelling opponents as "terrorists" has been used as a tactic to evade the usual laws of war against things such as assassinations and other extrajudicial killing, particularly by Israel and the United States.[better source needed][attribution needed] Some international legal opinions suggest that terrorist activities by their very nature "deny" the civilian nature of an ostensibly civilian participant. Some groups, when involved in a "liberation" struggle, have been called "terrorists" by the Western governments or media. Later, these same persons, as leaders of the liberated nations, are called "statesmen" by similar organizations. Two examples of this phenomenon are the Nobel Peace Prize laureates Menachem Begin and Nelson Mandela. WikiLeaks editor Julian Assange has been called a "terrorist" by Sarah Palin and Joe Biden. Inversely, some groups like the Afghan Mujahideen that were labelled as "freedom fighters" later became "terrorists" as alliances shifted. During the Second World War, the Malayan People's Anti-Japanese Army were allied with the British, but during the Malayan Emergency, members of its successor organisation (the Malayan National Liberation Army) started campaigns against them, and were branded "terrorists" as a result. Databases The following terrorism databases are or were made publicly available for research purposes, and track specific acts of terrorism: The following public report and index provides a summary of key global trends and patterns in terrorism around the world: The following publicly available resources index electronic and bibliographic resources on the subject of terrorism: The following terrorism databases are maintained in secrecy by the United States Government for intelligence and counterterrorism purposes: Jones and Libicki (2008) includes a table of 268 terrorist groups active between 1968 and 2006 with their status as of 2006: still active, splintered, converted to nonviolence, removed by law enforcement or military, or won. (These data are not in a convenient machine-readable format but are available.) Infographics See also Notes and references Bibliography Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Methane] | [TOKENS: 6055] |
Contents Methane Methane (US: /ˈmɛθeɪn/ METH-ayn, UK: /ˈmiːθeɪn/ MEE-thayn) is a chemical compound with the chemical formula CH4 (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it is difficult because it is a gas at standard temperature and pressure. In the Earth's atmosphere methane is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Methane is an organic hydrocarbon, and among the simplest of organic compounds. Naturally occurring methane is found both below ground and under the seafloor and is formed by both geological and biological processes. The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the atmosphere, it is known as atmospheric methane. The Earth's atmospheric methane concentration has increased by about 160% since 1750, with the overwhelming percentage caused by human activity. It accounted for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases, according to the 2021 Intergovernmental Panel on Climate Change report. Strong, rapid and sustained reductions in methane emissions could limit near-term warming and improve air quality by reducing global surface ozone. Methane has also been detected on other planets, including Mars, which has implications for astrobiology research. Properties and bonding Methane is a tetrahedral molecule with four equivalent C–H bonds. Its electronic structure is described by four bonding molecular orbitals (MOs) resulting from the overlap of the valence orbitals on C and H. The lowest-energy MO is the result of the overlap of the 2s orbital on carbon with the in-phase combination of the 1s orbitals on the four hydrogen atoms. Above this energy level is a triply degenerate set of MOs that involve overlap of the 2p orbitals on carbon with various linear combinations of the 1s orbitals on hydrogen. The resulting "three-over-one" bonding scheme is consistent with photoelectron spectroscopic measurements. Methane is an odorless, colourless and transparent gas at standard temperature and pressure. It does absorb visible light, especially at the red end of the spectrum, due to overtone bands, but the effect is only noticeable if the light path is very long. This is what gives Uranus and Neptune their blue or bluish-green colors, as light passes through their atmospheres containing methane and is then scattered back out. The familiar smell of natural gas as used in homes is achieved by the addition of an odorant, usually blends containing tert-butylthiol, as a safety measure. Methane has a boiling point of −161.5 °C at a pressure of one atmosphere. As a gas, it is flammable over a range of concentrations (5.4%–17%) in air at standard pressure. Solid methane exists in several modifications, of which nine are known. Cooling methane at normal pressure results in the formation of methane I. This substance crystallizes in the cubic system (space group Fm3m). The positions of the hydrogen atoms are not fixed in methane I, i.e. methane molecules may rotate freely. Therefore, it is a plastic crystal. Chemical reactions The primary chemical reactions of methane are combustion, steam reforming to syngas, and halogenation. In general, methane reactions are difficult to control. Partial oxidation of methane to methanol (CH3OH), a more convenient, liquid fuel, is challenging because the reaction typically progresses all the way to carbon dioxide and water even with an insufficient supply of oxygen. The enzyme methane monooxygenase produces methanol from methane, but cannot be used for industrial-scale reactions. Some homogeneously catalyzed systems and heterogeneous systems have been developed, but all have significant drawbacks. These generally operate by generating protected products which are shielded from overoxidation. Examples include the Catalytica system, copper zeolites, and iron zeolites stabilizing the alpha-oxygen active site. One group of bacteria catalyze methane oxidation with nitrite as the oxidant in the absence of oxygen, giving rise to the so-called anaerobic oxidation of methane. Like other hydrocarbons, methane is an extremely weak acid. Its pKa in DMSO is estimated to be 56. It cannot be deprotonated in solution, but the conjugate base is known in forms such as methyllithium. A variety of positive ions derived from methane have been observed, mostly as unstable species in low-pressure gas mixtures. These include methenium or methyl cation CH+3, methane cation CH+4, and methanium or protonated methane CH+5. Some of these have been detected in outer space. Methanium can also be produced as diluted solutions from methane with superacids. Cations with higher charge, such as CH2+6 and CH3+7, have been studied theoretically and conjectured to be stable. Despite the strength of its C–H bonds, there is intense interest in catalysts that facilitate C–H bond activation in methane (and other lower numbered alkanes). Methane's heat of combustion is 55.5 MJ/kg. Combustion of methane is a multiple step reaction summarized as follows: Peters four-step chemistry is a systematically reduced four-step chemistry that explains the burning of methane. Given appropriate conditions, methane reacts with halogen radicals as follows: where X is a halogen: fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). This mechanism for this process is called free radical halogenation. It is initiated when UV light or some other radical initiator (like peroxides) produces a halogen atom. A two-step chain reaction ensues in which the halogen atom abstracts a hydrogen atom from a methane molecule, resulting in the formation of a hydrogen halide molecule and a methyl radical (•CH3). The methyl radical then reacts with a molecule of the halogen to form a molecule of the halomethane, with a new halogen atom as byproduct. Similar reactions can occur on the halogenated product, leading to replacement of additional hydrogen atoms by halogen atoms with dihalomethane, trihalomethane, and ultimately, tetrahalomethane structures, depending upon reaction conditions and the halogen-to-methane ratio. This reaction is commonly used with chlorine to produce dichloromethane and chloroform via chloromethane. Carbon tetrachloride can be made with excess chlorine. Uses Methane may be transported as a refrigerated liquid (liquefied natural gas, or LNG). While leaks from a refrigerated liquid container are initially heavier than air due to the increased density of the cold gas, the gas at ambient temperature is lighter than air. Gas pipelines distribute large amounts of natural gas, of which methane is the principal component. Methane is used as a fuel for ovens, homes, water heaters, kilns, automobiles, rockets, turbines, etc. As the major constituent of natural gas, methane is important for electricity generation by burning it as a fuel in a gas turbine or steam generator. Compared to other hydrocarbon fuels, methane produces less carbon dioxide for each unit of heat released. At about 891 kJ/mol, methane's heat of combustion is lower than that of any other hydrocarbon, but the ratio of the heat of combustion (891 kJ/mol) to the molecular mass (16.0 g/mol, of which 12.0 g/mol is carbon) shows that methane, being the simplest hydrocarbon, produces more heat per mass unit (55.7 kJ/g) than other complex hydrocarbons. In many areas with a dense enough population, methane is piped into homes and businesses for heating, cooking, and industrial uses. In this context it is usually known as natural gas, which is considered to have an energy content of 39 megajoules per cubic meter, or 1,000 BTU per standard cubic foot. Liquefied natural gas (LNG) is predominantly methane converted into liquid form for ease of storage or transport. Refined liquid methane as well as LNG is used as a rocket fuel, when combined with liquid oxygen, as in the TQ-12, BE-4, Raptor, YF-215, and Aeon engines. Due to the similarities between methane and LNG such engines are commonly grouped together under the term methalox. As a liquid rocket propellant, a methane/liquid oxygen combination offers the advantage over kerosene/liquid oxygen combination, or kerolox, of producing small exhaust molecules, reducing coking or deposition of soot on engine components. Methane is easier to store than hydrogen due to its higher boiling point and density, as well as its lack of hydrogen embrittlement. The lower molecular weight of the exhaust also increases the fraction of the heat energy which is in the form of kinetic energy available for propulsion, increasing the specific impulse of the rocket. Compared to liquid hydrogen, the specific energy of methane is lower but this disadvantage is offset by methane's greater density and temperature range, allowing for smaller and lighter tankage for a given fuel mass. Liquid methane has a temperature range (91–112 K) nearly compatible with liquid oxygen (54–90 K). The fuel currently sees use in operational launch vehicles such as Zhuque-2, Vulcan and New Glenn as well as in-development launchers such as Starship, Neutron, Terran R, Nova, and Long March 9. Natural gas, which is mostly composed of methane, is used to produce hydrogen gas on an industrial scale. Steam methane reforming (SMR), or simply known as steam reforming, is the standard industrial method of producing commercial bulk hydrogen gas. More than 50 million metric tons are produced annually worldwide (2013), principally from the SMR of natural gas. Much of this hydrogen is used in petroleum refineries, in the production of chemicals and in food processing. Very large quantities of hydrogen are used in the industrial synthesis of ammonia. At high temperatures (700–1100 °C) and in the presence of a metal-based catalyst (nickel), steam reacts with methane to yield a mixture of CO and H2, known as "water gas" or "syngas": This reaction is strongly endothermic (consumes heat, ΔHr = 206 kJ/mol). Additional hydrogen is obtained by the reaction of CO with water via the water-gas shift reaction: This reaction is mildly exothermic (produces heat, ΔHr = −41 kJ/mol). Methane is also subjected to free-radical chlorination in the production of chloromethanes, although methanol is a more typical precursor. Hydrogen can also be produced via the direct decomposition of methane, also known as methane pyrolysis, which, unlike steam reforming, produces no greenhouse gases (GHG). The heat needed for the reaction can also be GHG emission free, e.g. from concentrated sunlight, renewable electricity, or burning some of the produced hydrogen. If the methane is from biogas then the process can be a carbon sink. Temperatures in excess of 1200 °C are required to break the bonds of methane to produce hydrogen gas and solid carbon. Through the use of a suitable catalyst the reaction temperature can be reduced to between 550 and 900 °C depending on the chosen catalyst. Dozens of catalysts have been tested, including unsupported and supported metal catalysts, carbonaceous and metal-carbon catalysts. The reaction is moderately endothermic as shown in the reaction equation below. As a refrigerant, methane has the ASHRAE designation R-50. Generation Methane can be generated through geological, biological or industrial routes. The two main routes for geological methane generation are (i) organic (thermally generated, or thermogenic) and (ii) inorganic (abiotic). Thermogenic methane occurs due to the breakup of organic matter at elevated temperatures and pressures in deep sedimentary strata. Most methane in sedimentary basins is thermogenic; therefore, thermogenic methane is the most important source of natural gas. Thermogenic methane components are typically considered to be relic (from an earlier time). Generally, formation of thermogenic methane (at depth) can occur through organic matter breakup, or organic synthesis. Both ways can involve microorganisms (methanogenesis), but may also occur inorganically. The processes involved can also consume methane, with and without microorganisms. The more important source of methane at depth (crystalline bedrock) is abiotic. Abiotic means that methane is created from inorganic compounds, without biological activity, either through magmatic processes[example needed] or via water-rock reactions that occur at low temperatures and pressures, like serpentinization. Most of Earth's methane is biogenic and is produced by methanogenesis, a form of anaerobic respiration only known to be conducted by some members of the domain Archaea. Methanogens occur in landfills and soils, ruminants (for example, cattle), the guts of termites, and the anoxic sediments below the seafloor and the bottom of lakes. This multistep process is used by these microorganisms for energy. The net reaction of methanogenesis is: The final step in the process is catalyzed by the enzyme methyl coenzyme M reductase (MCR). Wetlands are the largest natural sources of methane to the atmosphere, accounting for approximately 20–30% of atmospheric methane. Climate change is increasing the amount of methane released from wetlands due to increased temperatures and altered rainfall patterns. This phenomenon is called wetland methane feedback. Rice cultivation generates as much as 12% of total global methane emissions due to the long-term flooding of rice fields. Ruminants such as cattle belch out methane, accounting for about 22% of the U.S. annual methane emissions to the atmosphere. One study reported that the livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane. A 2013 study estimated that livestock accounted for 44% of human-induced methane and about 15% of human-induced greenhouse gas emissions. Many efforts are underway to reduce livestock methane production, such as medical treatments and dietary adjustments, and to trap the gas to use its combustion energy. Most of the subseafloor is anoxic because oxygen is removed by aerobic microorganisms within the first few centimeters of the sediment. Below the oxygen-replete seafloor, methanogens produce methane that is either used by other organisms or becomes trapped in gas hydrates. These other organisms that utilize methane for energy are known as methanotrophs ('methane-eating'), and are the main reason why little methane generated at depth reaches the sea surface. Consortia of Archaea and Bacteria have been found to oxidize methane via anaerobic oxidation of methane (AOM); the organisms responsible for this are anaerobic methanotrophic Archaea (ANME) and sulfate-reducing bacteria (SRB). Given its cheap abundance in natural gas, there is little incentive to produce methane industrially. Methane can be produced by hydrogenating carbon dioxide through the Sabatier process. Methane is also a side product of the hydrogenation of carbon monoxide in the Fischer–Tropsch process, which is practiced on a large scale to produce longer-chain molecules than methane. An example of large-scale coal-to-methane gasification is the Great Plains Synfuels plant, started in 1984 in Beulah, North Dakota as a way to develop abundant local resources of low-grade lignite, a resource that is otherwise difficult to transport for its weight, ash content, low calorific value and propensity to spontaneous combustion during storage and transport. A number of similar plants exist around the world, although mostly these plants are targeted towards the production of long chain alkanes for use as gasoline, diesel, or feedstock to other processes. Power to methane is a technology that uses electrical power to produce hydrogen from water by electrolysis and uses the Sabatier reaction to combine hydrogen with carbon dioxide to produce methane. Methane can be produced by protonation of methyl lithium or a methyl Grignard reagent such as methylmagnesium chloride. It can also be made from anhydrous sodium acetate and dry sodium hydroxide, mixed and heated above 300 °C (with sodium carbonate as byproduct).[citation needed] In practice, a requirement for pure methane can easily be fulfilled by steel gas bottle from standard gas suppliers. Occurrence Methane is the major component of natural gas, about 87% by volume. The major source of methane is extraction from geological deposits known as natural gas fields, with coal seam gas extraction becoming a major source (see coal bed methane extraction, a method for extracting methane from a coal deposit, while enhanced coal bed methane recovery is a method of recovering methane from non-mineable coal seams). It is associated with other hydrocarbon fuels, and sometimes accompanied by helium and nitrogen. Methane is produced at shallow levels (low pressure) by anaerobic decay of organic matter and reworked methane from deep under the Earth's surface. In general, the sediments that generate natural gas are buried deeper and at higher temperatures than those that contain oil. Methane is generally transported in bulk by pipeline in its natural gas form, or by LNG carriers in its liquefied form; few countries transport it by truck. Atmospheric methane and climate change Methane is an important greenhouse gas, responsible for around 30% of the rise in global temperatures since the industrial revolution. Methane has a global warming potential (GWP) of 29.8 ± 11 compared to CO2 (potential of 1) over a 100-year period, and 82.5 ± 25.8 over a 20-year period. This means that, for example, a leak of one tonne of methane is equivalent to emitting 82.5 tonnes of carbon dioxide. Burning methane and producing carbon dioxide also reduces the greenhouse gas impact compared to simply venting methane to the atmosphere. As methane is gradually converted into carbon dioxide (and water) in the atmosphere, these values include the climate forcing from the carbon dioxide produced from methane over these timescales. Annual global methane emissions are currently approximately 580 Mt, 40% of which is from natural sources and the remaining 60% originating from human activity, known as anthropogenic emissions. The largest anthropogenic source is agriculture, responsible for around one quarter of emissions, closely followed by the energy sector, which includes emissions from coal, oil, natural gas and biofuels. Historic methane concentrations in the world's atmosphere have ranged between 300 and 400 nmol/mol during glacial periods commonly known as ice ages, and between 600 and 700 nmol/mol during the warm interglacial periods. A 2012 NASA website said the oceans were a potential important source of Arctic methane, but more recent studies associate increasing methane levels as caused by human activity. Global monitoring of atmospheric methane concentrations began in the 1980s. The Earth's atmospheric methane concentration has increased 160% since preindustrial levels in the mid-18th century. In 2013, atmospheric methane accounted for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases. Between 2011 and 2019 the annual average increase of methane in the atmosphere was 1866 ppb. From 2015 to 2019 sharp rises in levels of atmospheric methane were recorded. In 2019, the atmospheric methane concentration was higher than at any time in the last 800,000 years. As stated in the AR6 of the IPCC, "Since 1750, increases in CO2 (47%) and CH4 (156%) concentrations far exceed, and increases in N2O (23%) are similar to, the natural multi-millennial changes between glacial and interglacial periods over at least the past 800,000 years (very high confidence)".[a] In February 2020, it was reported that fugitive emissions and gas venting from the fossil fuel industry may have been significantly underestimated. The largest annual increase occurred in 2021 with the overwhelming percentage caused by human activity. Climate change can increase atmospheric methane levels by increasing methane production in natural ecosystems, forming a climate change feedback. Another explanation for the rise in methane emissions could be a slowdown of the chemical reaction that removes methane from the atmosphere. Over 100 countries have signed the Global Methane Pledge, launched in 2021, promising to cut their methane emissions by 30% by 2030. This could avoid 0.2 °C of warming globally by 2050, although there have been calls for higher commitments in order to reach this target. The International Energy Agency's 2022 report states "the most cost-effective opportunities for methane abatement are in the energy sector, especially in oil and gas operations". Methane clathrates (also known as methane hydrates) are solid cages of water molecules that trap single molecules of methane. Significant reservoirs of methane clathrates have been found in arctic permafrost and along continental margins beneath the ocean floor within the gas clathrate stability zone, located at high pressures (1 to 100 MPa; lower end requires lower temperature) and low temperatures (< 15 °C; upper end requires higher pressure). Methane clathrates can form from biogenic methane, thermogenic methane, or a mix of the two. These deposits are both a potential source of methane fuel as well as a potential contributor to global warming. The global mass of carbon stored in gas clathrates is still uncertain and has been estimated as high as 12,500 Gt carbon and as low as 500 Gt carbon. The estimate has declined over time with a most recent estimate of ≈1800 Gt carbon. A large part of this uncertainty is due to our knowledge gap in sources and sinks of methane and the distribution of methane clathrates at the global scale. For example, a source of methane was discovered relatively recently in an ultraslow spreading ridge in the Arctic. Some climate models suggest that today's methane emission regime from the ocean floor is potentially similar to that during the period of the Paleocene–Eocene Thermal Maximum (PETM) around 55.5 million years ago, although there are no data indicating that methane from clathrate dissociation currently reaches the atmosphere. Arctic methane release from permafrost and seafloor methane clathrates is a potential consequence and further cause of global warming; this is known as the clathrate gun hypothesis. Data from 2016 indicate that Arctic permafrost thaws faster than predicted. Public safety and the environment Methane "degrades air quality and adversely impacts human health, agricultural yields, and ecosystem productivity". The 2015–2016 methane gas leak in Aliso Canyon, California was considered to be the worst in terms of its environmental effect in American history. It was also described as more damaging to the environment than Deepwater Horizon's leak in the Gulf of Mexico. In May 2023 The Guardian published a report blaming Turkmenistan as the worst in the world for methane super emitting. The data collected by Kayrros researchers indicate that two large Turkmen fossil fuel fields leaked 2.6 million and 1.8 million metric tonnes of methane in 2022 alone, pumping the CO2 equivalent of 366 million tonnes into the atmosphere, surpassing the annual CO2 emissions of the United Kingdom. Extraterrestrial methane Methane is abundant in many parts of the Solar System and potentially could be harvested on the surface of another Solar System body (in particular, using methane production from local materials found on Mars or Titan), providing fuel for a return journey. Negative methane, the negative ion of methane, is also known to exist in interstellar space. Its mechanism of formation is not fully understood. Methane has been detected on all planets of the Solar System and most of the larger moons.[citation needed] With the possible exception of Mars, it is believed to have come from abiotic processes. The Curiosity rover has documented seasonal fluctuations of atmospheric methane levels on Mars. These fluctuations peaked at the end of the Martian summer at 0.6 parts per billion. Methane has been proposed as a possible rocket propellant on future Mars missions due in part to the possibility of synthesizing it on the planet by in situ resource utilization. An adaptation of the Sabatier methanation reaction may be used with a mixed catalyst bed and a reverse water-gas shift in a single reactor to produce methane and oxygen from the raw materials available on Mars, utilizing water from the Martian subsoil and carbon dioxide in the Martian atmosphere. Methane could be produced by a non-biological process called serpentinization[b] involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars. Methane has been detected in vast abundance on Titan, the largest moon of Saturn. It comprises a significant portion of its atmosphere and also exists in a liquid form on its surface, where it comprises the majority of the liquid in Titan's vast lakes of hydrocarbons, the second largest of which is believed to be almost pure methane in composition. The presence of stable lakes of liquid methane on Titan, as well as the surface of Titan being highly chemically active and rich in organic compounds, has led scientists to consider the possibility of life existing within Titan's lakes, using methane as a solvent in the place of water for Earth-based life and using hydrogen in the atmosphere to derive energy with acetylene. History The discovery of methane is credited to Italian physicist Alessandro Volta, who characterized numerous properties including its flammability limit and origin from decaying organic matter. Volta was initially motivated by reports of inflammable air present in marshes by his friend Father Carlo Giuseppe Campi. While on a fishing trip to Lake Maggiore straddling Italy and Switzerland in November 1776, he noticed the presence of bubbles in the nearby marshes and decided to investigate. Volta collected the gas rising from the marsh and demonstrated that the gas was inflammable. Volta notes similar observations of inflammable air were present previously in scientific literature, including a letter written by Benjamin Franklin. Following the Felling mine disaster of 1812 in which 92 men perished, Sir Humphry Davy established that the feared firedamp was in fact largely methane. The name "methane" was coined in 1866 by the German chemist August Wilhelm von Hofmann. The name was derived from methanol. Etymology Etymologically, the word methane is coined from the chemical suffix "-ane", which denotes substances belonging to the alkane family; and the word methyl, which is derived from the German Methyl (1840) or directly from the French méthyle, which is a back-formation from the French méthylène (corresponding to English "methylene"), the root of which was coined by Jean-Baptiste Dumas and Eugène Péligot in 1834 from the Greek μέθυ méthy (wine) (related to English "mead") and ὕλη hýlē (meaning "wood"). The radical is named after this because it was first detected in methanol, an alcohol first isolated by distillation of wood. The chemical suffix -ane is from the coordinating chemical suffix -ine which is from Latin feminine suffix -ina which is applied to represent abstracts. The coordination of "-ane", "-ene", "-one", etc. was proposed in 1866 by German chemist August Wilhelm von Hofmann. The abbreviation CH4-C can mean the mass of carbon contained in a mass of methane, and the mass of methane is always 1.33 times the mass of CH4-C. CH4-C can also mean the methane-carbon ratio, which is 1.33 by mass. Methane at scales of the atmosphere is commonly measured in teragrams (Tg CH4) or millions of metric tons (MMT CH4), which mean the same thing. Other standard units are also used, such as nanomole (nmol, one billionth of a mole), mole (mol), kilogram, and gram. Safety Methane is an asphyxiant gas, meaning that it is non-toxic and the primary health hazard is displacement of oxygen in high enough concentrations, potentially causing death by asphyxiation. No systemic toxicity has been detected at 5% concentration in air. Methane is an extremely flammable gas at normal ambient temperature. It may form explosive mixtures with air. Methane gas explosions are responsible for many deadly mining disasters. A methane gas explosion was the cause of the Upper Big Branch coal mine disaster in West Virginia on April 5, 2010, killing 29. Natural gas accidental release has also been a major focus in the field of safety engineering, due to past accidental releases that concluded in the formation of jet fire disasters. See also Explanatory notes Citations Cited sources External links |
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Contents Islamic State The Islamic State (IS),[d] also known as the Islamic State of Iraq and the Levant (ISIL), the Islamic State of Iraq and Syria (ISIS), and the Daesh, is a transnational Salafi jihadist militant organisation and a former unrecognised quasi-state. IS occupied significant territory in Iraq and Syria in 2013, but lost most of it between 2017 and 2019. In 2014, the group proclaimed itself to be a worldwide caliphate, and claimed religious and political authority over all Muslims worldwide, a claim not accepted by the vast majority of Muslims. It is designated as a terrorist organisation by the United Nations and many countries around the world, including Muslim countries. By the end of 2015, its self-declared caliphate ruled an area with a population of about 12 million, where they enforced their extremist interpretation of Islamic law, managed an annual budget exceeding US$1 billion, and commanded more than 30,000 fighters. After a grinding conflict with American, Iraqi, and Kurdish forces, IS lost control of its Middle Eastern territories by 2019, subsequently reverting to insurgency from remote hideouts while continuing its propaganda efforts. These efforts have garnered a significant following in northern and Sahelian Africa, where IS still controls a significant territory. Originating in the Jaish al-Ta'ifa al-Mansurah founded by Abu Omar al-Baghdadi in 2004, the organisation (primarily under the Islamic State of Iraq name) affiliated itself with al-Qaeda in Iraq and fought alongside them during the 2003–2006 phase of the Iraqi insurgency. The group later changed its name to Islamic State of Iraq and Levant for about a year, before declaring itself to be a worldwide caliphate, called simply the Islamic State (الدولة الإسلامية, ad-Dawlah al-Islāmiyya). During its rule in Syria and Iraq, the group became notorious for its brutality. It committed genocides against Yazidis and Iraqi Turkmen; engaged in persecution of Christians, Shia Muslims, and Mandaeans; publicised videos of beheadings of soldiers, journalists, and aid workers; and destroyed cultural sites. The group has perpetrated terrorist massacres in territories outside of its control, such as the November 2015 Paris attacks, the 2024 Kerman bombings in Iran, the 2024 Crocus City Hall attack in Russia, the 2025 Bondi Beach shooting in Australia and 2025 Manchester synagogue attack on Yom Kippur. Lone wolf attacks inspired by the group have also taken place. After 2015, the Iraqi Armed Forces and the Syrian Democratic Forces pushed back IS and degraded its financial and military infrastructure, assisted by advisors, weapons, training, supplies, and airstrikes by the American-led coalition, and later by Russian airstrikes, bombings, cruise missile attacks, and scorched-earth tactics across Syria, which focused mostly on razing Syrian opposition strongholds rather than IS bases. By March 2019, IS lost the last of its territories in West Asia, although its affiliates maintain a significant territorial presence in Africa as of 2025. Name The Islamic State, abbreviated IS, is also known as the Islamic State of Iraq and the Levant (ISIL /ˈaɪsɪl/ EYE-sil), the Islamic State of Iraq and Syria (ISIS /ˈaɪsɪs/ EYE-siss), and by its Arabic acronym Daesh (داعش, Dāʿish, IPA: [ˈdaːʕɪʃ]), and also as Dawlat al-Islām (دولة الإسلام). In April 2013, having expanded into Syria, the group adopted the name ad-Dawla al-Islāmiyya fī l-ʿIrāq wa-sh-Shām (الدولة الإسلامية في العراق والشام). As al-Shām is a region often compared with the Levant or the region of Syria, the group's name has been variously translated as "Islamic State of Iraq and al-Sham", "Islamic State of Iraq and Syria" (both abbreviated as ISIS), or "Islamic State of Iraq and the Levant" (abbreviated as ISIL). In 2014, Dar al-Ifta al-Misriyyah dubbed ISIS as "QSIS" for "al-Qaeda Separatists in Iraq and Syria", arguing that the group does not represent the vast majority of Muslims. While the use of either one or the other acronym has been the subject of debate, the distinction between the two and its relevance has been considered less important. Of greater relevance is the name Daesh, which is an acronym of ISIL's Arabic name ad-Dawla al-Islamiyya fī l-ʿIrāq wa-sh-Shām, or Daesh. This name is widely used among the Muslim world, as well as ISIL's Arabic-speaking detractors, for example when referring to the group whilst speaking amongst themselves, although—and to a certain extent because—it is considered derogatory, as it resembles the Arabic words Daes ("one who crushes, or tramples down, something underfoot") and Dāhis (loosely translated as "one who sows discord"). Within areas under its control, ISIL considers use of the name Daesh punishable by flogging. In late June 2014, the group renamed itself ad-Dawla al-Islāmiyya (lit. 'Islamic State' or IS), declaring itself a worldwide caliphate. The name "Islamic State" and the group's claim to be a caliphate have been widely rejected, with the UN, various governments, and mainstream Muslim groups refusing to use the new name. The group's declaration of a new caliphate in June 2014 and its adoption of the name "Islamic State" have been criticised and ridiculed by Muslim scholars and rival Islamists both inside and outside the territory it controls. In a speech in September 2014, United States president Barack Obama said that ISIL was neither Islamic (on the basis that no religion condones the killing of innocents) nor a state (in that no government recognises the group as a state), while many object to using the name Islamic State owing to the far-reaching religious and political claims to authority which that name implies. The United Nations Security Council, the United States, Canada, Turkey, Australia, the United Kingdom, and other countries generally call the group ISIL, while much of the Arab world uses the Arabic acronym Dāʻish or Daesh. France's Foreign Minister Laurent Fabius said: "This is a terrorist group and not a state. I do not recommend using the term Islamic State because it blurs the lines between Islam, Muslims, and Islamists. The Arabs call it 'Daesh' and I will be calling them the 'Daesh cutthroats'." Retired general John Allen, the U.S. envoy appointed to co-ordinate the coalition; U.S. Army Lieutenant General James Terry, head of operations against the group; and Secretary of State John Kerry had all shifted towards use of the term Daesh by December 2014, which nonetheless remained a pejorative in 2021. Purpose and strategy The ideology of the Islamic State has been described as being a hybrid of Salafism, Salafi jihadism, Islamic fundamentalism, Wahhabism, and Qutbism, as well as other doctrines. According to Robert Manne, there is a "general consensus" that the ideology of the Islamic State is "primarily based upon the writings of the radical Egyptian theoretician Sayyid Qutb". The Muslim Brotherhood began the trend of political Islamism in the 20th century, seeking gradual establishment of a new Caliphate, a comprehensive Islamic society ruled by sharia law. Qutb's doctrines of jahiliyya (pre-Islamic ignorance), hakimiyya (divine sovereignty), and takfir of entire societies formed a radicalised vision of the Muslim Brotherhood's political Islam project. Qutbism became the precursor to all jihadist thought, from Abdullah Azzam to Zawahiri and to Daesh. Alongside Sayyid Qutb, the most invoked ideological figures of IS include Ibn Taymiyya, Abdullah Azzam, and Abu Bakr Naji. Although IS claims to adhere to the Salafi theology of Ibn Taymiyyah, it rejects traditional Salafi interpretations as well as the four Sunni schools of law, and anathematises the majority of Salafis as heretics. IS ideologues rarely uphold adherence to Islamic scholarship and law manuals for reference, mostly preferring to derive rulings based on self-interpretation of the Qur'an and Muslim traditions. Abu Omar al-Baghdadi, the first Emir of the Islamic State of Iraq, was radicalised as a Muslim Brotherhood member during his youth. Motaz Al-Khateeb states that religious texts and Islamic jurisprudence "alone cannot explain the emergence" of Daesh since the Muslim Brotherhood and Daesh "draw on the same Islamic jurisprudence" but "are diametrically opposite" in strategy and behaviour. Through the official statement of beliefs originally released by al-Baghdadi in 2007 and subsequently updated since June 2014, ISIL defined its creed as "a middle way between the extremist Kharijites and the lax Murji'ites".: 38 ISIL's ideology represents radical Jihadi-Salafi Islam, a strict, puritanical form of Sunni Islam. Muslim organisations like Islamic Networks Group (ING) in America have argued against this interpretation of Islam. ISIL promotes religious violence, and regards Muslims who do not agree with its interpretations as infidels or apostates. According to Hayder al Khoei, IS's philosophy is represented by the symbolism in the Black Standard variant of the legendary battle flag of Muhammad that it has adopted: the flag shows the Seal of Muhammad within a white circle, with the phrase above it, "There is no god but Allah". This symbolism is said to symbolise IS's belief that it represents the restoration of the caliphate of early Islam, with all the political, religious, and eschatological ramifications that this would imply. Abu Abdullah al-Muhajir, an Egyptian Jihadist theoretician and ideologue is considered as the key inspiration for early figures of IS. Al-Muhajir's legal manual on violence, Fiqh ad-Dima (The Jurisprudence of Jihad or The Jurisprudence of Blood), was adopted by IS as its standard reference for justifying its extraordinary acts of violence. The book has been described by counter-terrorism scholar Orwa Ajjoub as rationalising and justifying "suicide operations, the mutilation of corpses, beheading, and the killing of children and non-combatants". His theological and legal justifications influenced IS, al-Qaeda, and Boko Haram, as well as several other jihadi terrorist groups. Media outlets have compared his reference manual to Abu Bakr Naji's Management of Savagery, widely read among IS's commanders and fighters. IS adheres to global jihadist principles and follows the hard-line ideology of al-Qaeda and many other modern-day jihadist groups. For their guiding principles, the leaders of the Islamic State ... are open and clear about their almost exclusive commitment to the Wahhabi movement of Sunni Islam. The group circulates images of Wahhabi religious textbooks from Saudi Arabia in the schools it controls. Videos from the group's territory have shown Wahhabi texts plastered on the sides of an official missionary van. — David D. Kirkpatrick, The New York Times According to The Economist, Saudi practices followed by the group include the establishment of religious police to root out "vice" and enforce attendance at Salah prayers, the widespread use of capital punishment, and the destruction or re-purposing of any non-Sunni religious buildings. Bernard Haykel has described IS leader Abu Bakr al-Baghdadi's creed as "a kind of untamed Wahhabism". Senior Saudi religious leaders have issued statements condemning IS, and attempting to distance the group from official Saudi religious beliefs. What connection, if any, there is between Salafi-Jihadism of IS and Wahhabism and Salafism proper is disputed. IS borrowed two elements of Qutbism and 20th century Islamism into its version of Wahhabi worldview. While Wahhabism shuns violent rebellion against earthly rulers, IS embraces political call to revolutions. While historically Wahhabis were not champion activists of a Caliphate, IS borrowed the idea of restoration of a global Caliphate. Although the religious character of IS is mostly Wahhabi, it departs from the Wahhabi tradition in four critical aspects: dynastic alliance, call to establish a global caliphate, sheer violence, and apocalyptism. IS did not follow the pattern of the first three Saudi states in allying the religious mission of the Najdi ulema with the Al Saud family, rather they consider them apostates. The call for a global caliphate is another departure from Wahhabism. The caliphate, understood in Islamic law as the ideal Islamic polity uniting all Muslim territories, does not figure much in traditional Najdi writings. Ironically, Wahhabism emerged as an anti-caliphate movement. Although violence was not absent in the First Saudi State, Islamic State's displays of beheading, immolation, and other forms of violence aimed at inspiring fear are not in imitation of early Saudi practices. They were introduced by Abu Musab Al-Zarqawi, former leader of Al-Qaeda in Iraq, who took inspiration from the Egyptian Jihadi scholar, Abu Abdallah Al Muhajir. It is the latter's legal manual on violence, popularly known as Fiqh ad-Dima (The Jurisprudence of Blood), that is the Islamic State's standard reference for justifying its acts of violence. The Islamic State's apocalyptic dimension also lacks a mainstream Wahhabi precedent. IS aims to return to the early days of Islam, rejecting all innovations in the religion, which it believes corrupts its original spirit. It condemns later caliphates and the Ottoman Empire for deviating from what it calls pure Islam and seeks to revive the original Qutbist project of the restoration of a global caliphate that is governed by a strict Salafi-Jihadi doctrine. Following Salafi-Jihadi doctrines, IS condemns the followers of secular law as disbelievers, putting the current Saudi Arabian government in that category. IS believes that only a legitimate authority can undertake the leadership of jihad and that the first priority over other areas of combat, such as fighting non-Muslim countries, is the purification of Islamic society. For example, IS regards the Palestinian Sunni group Hamas as apostates who have no legitimate authority to lead jihad and see fighting Hamas as the first step towards confrontation by IS with Israel. Yemeni journalist Abdulelah Haider Shaye said: The Islamic State was drafted by Sayyid Qutb, taught by Abdullah Azzam, globalized by Osama bin Laden, transferred to reality by Abu Musab al-Zarqawi, and implemented by al-Baghdadis: Abu Omar and Abu Bakr. [...] The Islamic State added a focus on sectarianism to a layer of radical views. In particular, it linked itself to the Salafi-jihadi movement that evolved out of the Afghan jihad. — Hassan Hassan, The Sectarianism of the Islamic State: Ideological Roots and Political Context. One difference between IS and other Islamist and jihadist movements, including al-Qaeda, is the group's emphasis on eschatology and apocalypticism—that is, a belief in a final Day of Judgment by God. IS believes that it will defeat the army of "Rome" at the town of Dabiq. The noted scholar of militant Islamism Will McCants writes: References to the End Times fill Islamic State propaganda. It's a big selling point with foreign fighters, who want to travel to the lands where the final battles of the apocalypse will take place. The civil wars raging in those countries today [Iraq and Syria] lend credibility to the prophecies. The Islamic State has stoked the apocalyptic fire. ... For Bin Laden's generation, the apocalypse wasn't a great recruiting pitch. Governments in the Middle East two decades ago were more stable, and sectarianism was more subdued. It was better to recruit by calling to arms against corruption and tyranny than against the Antichrist. Today, though, the apocalyptic recruiting pitch makes more sense than before. — William McCants, The ISIS Apocalypse: The History, Strategy, and Doomsday Vision of the Islamic State Since at latest 2004, a significant goal of the group has been the foundation of a Sunni Islamic state. Specifically, ISIL has sought to establish itself as a caliphate, an Islamic state led by a group of religious authorities under a supreme leader—the caliph—who is believed to be the successor to Muhammad. In June 2014, ISIL published a document in which it claimed to have traced the lineage of its leader al-Baghdadi back to Muhammad, and upon proclaiming a new caliphate on 29 June, the group appointed al-Baghdadi as its caliph. As caliph, he demanded the allegiance of all devout Muslims worldwide according to Islamic jurisprudence (fiqh). ISIL has detailed its goals in its Dabiq magazine, saying it will continue to seize land and take over the entire Earth until its: Blessed flag...covers all eastern and western extents of the Earth, filling the world with the truth and justice of Islam and putting an end to the falsehood and tyranny of jahiliyyah [state of ignorance], even if America and its coalition despise such. — 5th edition of Dabiq, the Islamic State's English-language magazine According to German journalist Jürgen Todenhöfer, who spent ten days embedded with ISIL in Mosul, the view he kept hearing was that ISIL wants to "conquer the world", and that all who do not believe in the group's interpretation of the Quran will be killed. Todenhöfer was struck by the ISIL fighters' belief that "all religions who agree with democracy have to die", and by their "incredible enthusiasm"—including enthusiasm for killing "hundreds of millions" of people. When the caliphate was proclaimed, ISIL stated: "The legality of all emirates, groups, states and organisations becomes null by the expansion of the khilafah's [caliphate's] authority and the arrival of its troops to their areas." This was a rejection of the political divisions in Southwestern Asia that were established by the UK and France during World War I in the Sykes–Picot Agreement. All non-Muslim areas would be targeted for conquest after the Muslim lands were dealt with, according to the Islamist manual Management of Savagery. Documents found after the death of Samir Abd Muhammad al-Khlifawi, a former colonel in the intelligence service of the Iraqi Air Force before the US invasion who had been described as "the strategic head" of ISIL, detailed planning for the ISIL takeover of northern Syria, which made possible "the group's later advances into Iraq". Al-Khlifawi called for the infiltration of areas to be conquered with spies who would find out "as much as possible about the target towns: Who lived there, who was in charge, which families were religious, which Islamic school of religious jurisprudence they belonged to, how many mosques there were, who the imam was, how many wives and children he had and how old they were". Following this surveillance and espionage would come murder and kidnapping—"the elimination of every person who might have been a potential leader or opponent". In Raqqa, after rebel forces drove out the Assad regime and ISIL infiltrated the town, "first dozens and then hundreds of people disappeared". Security and intelligence expert Martin Reardon has described IS's purpose as being to psychologically "break" those under its control, "so as to ensure their absolute allegiance through fear and intimidation", while generating "outright hate and vengeance" among its enemies. Jason Burke, a journalist writing on Salafi jihadism, has written that IS's goal is to "terrorize, mobilize [and] polarize". Its efforts to terrorise are intended to intimidate civilian populations and force governments of the target enemy "to make rash decisions that they otherwise would not choose". It aims to mobilise its supporters by motivating them with, for example, spectacular deadly attacks deep in Western territory (such as the November 2015 Paris attacks), to polarise by driving Muslim populations—particularly in the West—away from their governments, thus increasing the appeal of IS's self-proclaimed caliphate among them, and to: "Eliminate neutral parties through either absorption or elimination". Journalist Rukmini Maria Callimachi also emphasises IS's interest in polarisation or in eliminating what it calls the "grey zone" between the black (non-Muslims) and white (IS). "The gray is moderate Muslims who are living in the West and are happy and feel engaged in the society here." A work published online in 2004 entitled Management of Savagery (Idarat at Tawahoush), described by several media outlets as influential on IS and intended to provide a strategy to create a new Islamic caliphate, recommended a strategy of attack outside its territory in which fighters would "Diversify and widen the vexation strikes against the Crusader-Zionist enemy in every place in the Islamic world, and even outside of it if possible, so as to disperse the efforts of the alliance of the enemy and thus drain it to the greatest extent possible." The group has been accused of attempting to "bolster morale" and distract attention from its loss of territory to enemies by staging terror attacks abroad (such as the 2016 Berlin truck attack, the 6 June 2017 attacks on Tehran, the 22 May 2017 bombing in Manchester, and the 3 June 2017 attacks in London that IS claimed credit for). Organisation IS has been described as a militant group adhering to Salafi jihadism. Raqqa in Syria was under IS control from 2013 and in 2014 it became the group's de facto capital city. On 17 October 2017, following a lengthy battle that saw massive destruction to the city, the Syrian Democratic Forces (SDF) announced the full capture of Raqqa from IS. From 2013 to 2019, IS was headed and run by Abu Bakr al-Baghdadi, the Islamic State's self-styled Caliph. Before their deaths, he had two deputy leaders, Abu Muslim al-Turkmani for Iraq and Abu Ali al-Anbari (also known as Abu Ala al-Afri) for Syria, both ethnic Turkmen. Advising al-Baghdadi were a cabinet of senior leaders, while its operations in Iraq and Syria are controlled by local 'emirs,' who head semi-autonomous groups that the Islamic State refers to as its provinces. Beneath the leaders are councils on finance, leadership, military matters, legal matters (including decisions on executions) foreign fighters' assistance, security, intelligence and media. In addition, a shura council has the task of ensuring that all decisions made by the governors and councils comply with the group's interpretation of sharia. While al-Baghdadi had told followers to "advise me when I err" in sermons, according to observers "any threat, opposition, or even contradiction is instantly eradicated". According to Iraqis, Syrians, and analysts who study the group, almost all of IS's leaders—including the members of its military and security committees and the majority of its emirs and princes—are former Iraqi military and intelligence officers, specifically former members of Saddam Hussein's Ba'ath government who lost their jobs and pensions in the de-Ba'athification process after that regime was overthrown. The former Chief Strategist in the Office of the Coordinator for Counterterrorism of the US State Department, David Kilcullen, has said, "There undeniably would be no Isis if we had not invaded Iraq." It has been reported that Iraqis and Syrians have been given greater precedence over other nationalities within IS because the group needs the loyalties of the local Sunni populations in both Syria and Iraq in order to be sustainable. Other reports, however, have indicated that Syrians are at a disadvantage to foreign members, with some native Syrian fighters resenting "favouritism" allegedly shown towards foreigners over pay and accommodation. In August 2016, media reports based on briefings by Western intelligence agencies suggested that IS had a multilevel secret service known in Arabic as Emni, established in 2014, that has become a combination of an internal police force and an external operations directorate complete with regional branches. The unit was believed to be under the overall command of IS's most senior Syrian operative, spokesman and propaganda chief Abu Mohammad al-Adnani until his death by airstrike in late August 2016. On 27 October 2019, the United States conducted a special operation targeting al-Baghdadi's compound in Barisha, Idlib, Northwest Syria. The attack resulted in al-Baghdadi's death; caught by surprise and unable to escape, al-Baghdadi detonated a suicide vest, deliberately killing both himself and two children[ambiguous] who had been living in the compound prior to the assault. U.S. President Donald Trump stated in a televised announcement that Baghdadi had, in fact, died during the operation and that American forces used support from helicopters, jets and drones through airspace controlled by Russia and Turkey. He said, "Russia treated us great... Iraq was excellent. We really had great cooperation" and Turkey knew they were going in. He thanked Turkey, Russia, Syria, Iraq and the Syrian Kurdish forces for their support. The Turkish Defence Ministry also confirmed on Sunday that Turkish and U.S. military authorities exchanged and coordinated information ahead of an attack in Syria's Idlib. Fahrettin Altun, a senior aide to Turkish President Tayyib Erdogan, also stated, among other things, "Turkey was proud to help the United States, our NATO ally, bring a notorious terrorist to justice" and that Turkey "will continue to work closely with the United States and others to combat terrorism in all its forms and manifestations." Kremlin spokesman Dmitry Peskov declined to say if the United States had told Russia about the raid in advance but said that its result if confirmed, represented a serious contribution by the United States to combat terrorism. Russia had previously claimed Baghdadi was killed in May 2017 by their airstrike. In September 2019, a statement attributed to IS's propaganda arm, the Amaq news agency, claimed that Abdullah Qardash was named as al-Baghdadi's successor. Analysts dismissed this statement as a fabrication, and relatives were reported as saying that Qardash died in 2017. Rita Katz, a terrorism analyst and the co-founder of SITE Intelligence, noted that the alleged statement used a different font when compared to other statements and it was never distributed on Amaq or IS channels. On 29 October 2019, Trump stated on social media that al-Baghdadi's "number one replacement" had been killed by American forces, without giving a name. A U.S. official later confirmed that Trump was referring to IS spokesman and senior leader Abul-Hasan al-Muhajir, who was killed in a U.S. airstrike in Syria two days earlier. On 31 October, IS named Abu Ibrahim al-Hashemi al-Qurayshi as Baghdadi's successor. On 3 February 2022, it was reported by a US official that al-Hashimi killed himself and members of his family by triggering an explosive device, during a counter-terrorism raid by the US Joint Special Operations Command. On 30 November 2022, IS announced that their next leader, Abu al-Hasan al-Hashimi al-Qurashi, had been killed in battle and named a successor, providing no additional information other than his pseudonym, Abu al-Hussein al-Husseini al-Qurashi, who was believed to be the Islamic State's first Syrian chief. A spokesman for U.S. Central Command confirmed that IS's leader had been killed in mid-October by anti-government rebels in southern Syria. On 16 February 2023, senior IS leader Hamza al-Homsi blew himself up in a U.S.-led raid in Syria. On 23 April 2023, IS leader Abu al-Hussein al-Husseini al-Qurashi was killed in an attack on his residence at Jindires, in the northwestern Idlib Governorate. Turkey claimed responsibility for his death, while the Islamic State claimed that al-Husseini al-Qurashi was killed in a shootout with Tahrir al-Sham (HTS) forces. Subsequently, the Islamic State named Abu Hafs al-Hashimi al-Qurashi as their new leader. In late August 2025, US Special Forces carried out a helicopter raid at Atmeh, near the Turkish border region. They killed two senior IS leaders in the raid, including a figure who was believed to be next-in-line for the Islamic State leadership. Analysts believe that the Islamic State is headquartered in the northwestern Idlib Governorate region, near the Turkish border, ever since the group lost their last territorial stronghold at Al-Baghuz Fawqani in Spring 2019. In 2014, The Wall Street Journal estimated that eight million people lived in the Islamic State. The United Nations Commission on Human Rights has stated that IS "seeks to subjugate civilians under its control and dominate every aspect of their lives through terror, indoctrination, and the provision of services to those who obey". Civilians, as well as the Islamic State itself, have released footage of some of the human rights abuses. Social control of civilians was by imposition of IS's reading of sharia law, enforced by morality police forces known as Al-Hisbah and the all-women Al-Khanssaa Brigade, a general police force, courts, and other entities managing recruitment, tribal relations, and education. Al-Hisbah was led by Abu Muhammad al-Jazrawi. In 2015, IS published a penal code including floggings, amputations, crucifixions, etc. Estimates of the size of IS's military have varied widely, from tens of thousands up to 200,000. In early 2015, journalist Mary Anne Weaver estimated that half of IS fighters were foreigners. A UN report estimated a total of 15,000 fighters from over 80 countries were in IS's ranks in November 2014. US intelligence estimated an increase to around 20,000 foreign fighters in February 2015, including 3,400 from the Western world. In September 2015, the CIA estimated that 30,000 foreign fighters had joined IS. According to Abu Hajjar, a former senior leader of IS, foreign fighters receive food, petrol and housing, but unlike native Iraqi or Syrian fighters, they do not receive payment in wages. Since 2012, more than 3,000 people from the central Asian countries have gone to Syria, Iraq or Afghanistan to join the Islamic State or Jabhat al Nusra. IS relies mostly on captured weapons with major sources including Saddam Hussein's Iraqi stockpiles from the 2003–11 Iraq insurgency and weapons from government and opposition forces fighting in the Syrian Civil War and during the post-US withdrawal Iraqi insurgency. The captured weapons, including armour, guns, surface-to-air missiles, and even some aircraft, enabled rapid territorial growth and facilitated the capture of additional equipment. For example, IS captured US-made TOW anti-tank missiles supplied by the United States and Saudi Arabia to the Free Syrian Army in Syria. Ninety percent of the group's weapons ultimately originated in China, Russia or Eastern Europe according to Conflict Armament Research. The group uses truck and car bombs, suicide bombers and IEDs, and has used chemical weapons in Iraq and Syria. IS captured nuclear materials from Mosul University in July 2014, but is unlikely to be able to convert them into weapons. In September 2015 a US official stated that IS was manufacturing and using mustard agent in Syria and Iraq, and had an active chemical weapons research team. IS has also used water as a weapon of war. The group closed the gates of the smaller Nuaimiyah dam in Fallujah in April 2014, flooding the surrounding regions, while cutting the water supply to the Shia-dominated south. Around 12,000 families lost their homes and 200 square kilometres (77 mi2) of villages and fields were either flooded or dried up. The economy of the region also suffered with destruction of cropland and electricity shortages. During the Battle of Mosul, commercially available quadcopters and drones were being used by IS as surveillance and weapons delivery platforms using improvised cradles to drop grenades and other explosives. One IS drone base was struck and destroyed by two Royal Air Force Tornado using two Paveway IV guided bombs. IS publishes material directed at women, with media groups encouraging them to play supportive roles within IS, such as providing first aid, cooking, nursing and sewing skills, in order to become "good wives of jihad". In 2015, it was estimated that western women made up over 550, or 10%, of IS's western foreign fighters. Until 2016, women were generally confined to a "women's house" upon arrival, which they were forbidden to leave. These houses were often small, dirty and infested with vermin and food supply was scarce. There they remained until they either had found a husband, or the husband they arrived with had completed his training. After being allowed to leave the confinement, women still generally spent most of their days indoors, where their lives are devoted to caring for their husbands and the vast majority of women in the conflict area have children. Mothers play an important role passing on IS ideology to their children. Widows are encouraged to remarry. In a document entitled Women in the Islamic State: Manifesto and Case Study released by the media wing of IS's all-female Al-Khansaa Brigade, emphasis is given to the paramount importance of marriage and motherhood (as early as nine years old). Women should live a life of "sedentariness", fulfilling her "divine duty of motherhood" at home, with a few exceptions like teachers and doctors. Equality for women is opposed, as is education on non-religious subjects, the "worthless worldly sciences". According to a 2015 study by the Financial Action Task Force, IS's five primary sources of revenue are as follows (listed in order of significance): Since 2012, IS has produced annual reports giving numerical information on its operations, somewhat in the style of corporate reports, seemingly in a bid to encourage potential donors. In 2014, the RAND Corporation analysed IS's funding sources from documents captured between 2005 and 2010. It found that outside donations amounted to only 5% of the group's operating budgets, and that cells inside Iraq were required to send up to 20% of the income generated from kidnapping, extortion rackets and other activities to the next level of the group's leadership, which would then redistribute the funds to provincial or local cells that were in difficulties or needed money to conduct attacks. In 2016, RAND estimated that IS finances from its largest source of income—oil revenues and the taxes it extracts from people under its control—had fallen from about US$1.9 billion in 2014 to US$870 million in 2016. In mid-2014, the Iraqi National Intelligence Service obtained information that IS had assets worth US$2 billion, making it the richest jihadist group in the world. About three-quarters of this sum was said to looted from Mosul's central bank and commercial banks in the city. However, doubt was later cast on whether IS was able to retrieve anywhere near that sum from the central bank, and even on whether the looting had actually occurred. In 2022, the company Lafarge was found guilty in paying IS for the operation of its facilities. "In 2013–2014 the company transferred $6,000,000 to ISIL so they could continue company operations. This allowed the company to earn $70 million in sales revenue from a plant it operated in northern Syria, prosecutors said." Lafarge, which merged with Holcim in 2015, agreed to pay $778 million in forfeiture and fines as part of a plea agreement not to be convicted and sentenced to prison for providing material support to a terrorist organisation. No Lafarge executives were charged in the United States, while French authorities arrested some of the executives involved but didn't provide names. The U.S. court lists six unnamed Lafarge executives. Lafarge evacuated the cement plant in September 2014, Afterwards IS took possession of the remaining cement and sold it for an estimated $3.21 million. SIX Swiss Exchange trading suspended trading for Holcim shares before the news became public. After trading resumed shares rose by 3.2%. IS attempted to create a modern gold dinar by minting gold, silver, and copper coins, based on the coinage used by the Umayyad Caliphate in the seventh century. Despite a propaganda push for the currency, adoption appeared to have been minimal and its internal economy was effectively dollarised, even with regards to its own fines. The education in IS held territory was organised by the Diwan of Education. IS introduced its own curriculum, which did not include lessons in history, music, geography or art, but included lectures in Islamic Law, Sharia, and Jihad. The Diwan of Education was often in competition with the Diwan of Outreach and Mosques, which organised educational centres focused on the sharia. Origins The group was founded in 1999 by Jordanian Salafi jihadist Abu Musab al-Zarqawi under the name Jamāʻat al-Tawḥīd wa-al-Jihād (lit. 'The Organisation of Monotheism and Jihad'). In a letter published by the Coalition Provisional Authority in February 2004, Zarqawi wrote that jihadis should use bombings to start an open sectarian war so that Sunnis from the Islamic world would mobilise against assassinations carried out by Shia, specifically the Badr Brigade, against Ba'athists and Sunnis.[excessive citations] It is possible that Zarqawi used some "small seed money" of $200,000 obtained from Al Qaeda to set up a training camp for the JTJ. The financial support from Al Qaeda came after Zarqawi was reluctant to be recruited by bin Laden. Following the 11 September Attacks and the decision to invade Iraq, the U.S. Secretary of State's presentation to the United States Security Council aimed to establish Zarqawi as the definitive link between Al Qaeda and Iraq. These claims were later disproved. Powell's presentation was nevertheless instrumental in elevating Zarqawi's status and laying the groundwork for part of the foreign fighter faction of the Iraqi insurgency.[fact or opinion?] The JTJ officially pledged allegiance to al-Qaeda in a letter in October 2004, which drew more recruits, as well as financial and logistical support. Territorial control and claims As a self-proclaimed worldwide caliphate, IS claims religious, political and military authority over all Muslims worldwide, and that "the legality of all emirates, groups, states, and organisations, becomes null by the expansion of the khilāfah's [caliphate's] authority and arrival of its troops to their areas". In Iraq and Syria, IS used many of those countries' existing governorate boundaries to subdivide territory it conquered and claimed; it called these divisions wilayah or provinces. By June 2015, IS had also established official "provinces" in Libya, Egypt (Sinai Peninsula), Saudi Arabia, Yemen, Algeria, Afghanistan, Pakistan, Nigeria and the North Caucasus. IS received pledges of allegiance and published media releases via groups in Somalia, Bangladesh, Indonesia, Myanmar, Thailand and the Philippines, but it has not announced any further official branches, instead identifying new affiliates as simply "soldiers of the caliphate". At its peak, IS was sometimes described as a quasi-state. By March 2019, IS had lost most of its territory in its former core areas in Syria and Iraq, and was reduced to a desert pocket as well as insurgent cells. Through late 2020 and early 2021, IS African affiliates had once again seized territory and settlements in conflicts such as the Boko Haram insurgency, in Nigeria and the Insurgency in Cabo Delgado, in Mozambique. Notable takeovers by IS include Mocímboa da Praia and the Sambisa Forest. On 17 November 2021, IS supporters urged establishment of "New Provinces" in Indonesia. In October 2022, IS's Sahel province captured the rural committee and town of Ansongo in Mali. In 2023–2024, IS still held a large territory in Africa. IS affiliates International reaction The group has attracted widespread criticism internationally for its extremism, from governments and international bodies such as the United Nations and Amnesty International. On 24 September 2014, United Nations Secretary-General Ban Ki-moon stated: "As Muslim leaders around the world have said, groups like ISIL—or Da'ish—have nothing to do with Islam, and they certainly do not represent a state. They should more fittingly be called the 'Un-Islamic Non-State'." ISIL has been classified a terrorist organisation by the United Nations, the European Union and its member states, the United States, Russia, India, Turkey, Saudi Arabia and many other countries. Over 60 countries are directly or indirectly waging war against ISIL (see § Countries and groups at war with IS). The group was described as a cult in a Huffington Post column by notable cult authority Steven Hassan. Twitter has removed many accounts used to spread IS propaganda, and Google developed a "Redirect Method" that identifies individuals searching for IS-related material and redirects them to content that challenges IS narratives. The group's declaration of a caliphate has been criticised and its legitimacy has been disputed by Middle Eastern governments, by Sunni Muslim theologians and historians as well as other jihadist groups. Around the world, Islamic religious leaders have overwhelmingly condemned ISIL's ideology and actions, arguing that the group has strayed from the path of true Islam and that its actions do not reflect the religion's real teachings or virtues. Extremism within Islam goes back to the seventh century, to the Khawarijes. From their essentially political position, the Kharijites developed extreme doctrines that set them apart from both mainstream Sunni and Shia Muslims. They were particularly noted for adopting a radical approach to takfir, whereby they declared other Muslims to be unbelievers and therefore deemed worthy of death. Other scholars have also described the group not as Sunnis, but as Khawarij. Sunni critics, including Salafi and jihadist muftis such as Adnan al-Aroor and Abu Basir al-Tartusi, say that ISIL and related terrorist groups are not Sunnis, but are instead modern-day Kharijites (Muslims who have stepped outside the mainstream of Islam) serving an imperial anti-Islamic agenda. ISIS has been excommunicated from Islam by a number of scholars. Sheikh Muhammad al-Yaqoubi enumerated in his book, Refuting ISIS, that their form of Kharijism has removed them from Islam and fighting them is a religious duty, stating: "ISIS' leaders are people of unbelief and misguidance, and Muslims should not be lured by their jihad or deceived by their propaganda, as their actions speak louder than their words." Abd al-Aziz ibn Baz, the former Grand Mufti of Saudi Arabia, also stated that Kharijites are not Muslims, saying: "the majority are of the opinion that they are disobedient and misguided innovators, though they do not deem them unbelievers. However, the correct opinion is that they are unbelievers." In late August 2014, the Grand Mufti of Saudi Arabia, Abdul-Aziz ibn Abdullah Al ash-Sheikh, condemned ISIL and al-Qaeda saying, "Extremist and militant ideas and terrorism which spread decay on Earth, destroying human civilisation, are not in any way part of Islam, but are enemy number one of Islam, and Muslims are their first victims". In late September 2014, 126 Sunni imams and Islamic scholars—primarily Sufi—from around the Muslim world signed an open letter to the Islamic State's leader al-Baghdadi, explicitly rejecting and refuting his group's interpretations of Islamic scriptures, the Quran and hadith, which it used in order to justify its actions. "[You] have misinterpreted Islam into a religion of harshness, brutality, torture and murder ... this is a great wrong and an offence to Islam, to Muslims and to the entire world", the letter states. It rebukes the Islamic State for its killing of prisoners, describing the killings as "heinous war crimes" and its persecution of the Yazidis of Iraq as "abominable". Referring to the "self-described 'Islamic State'", the letter censures the group for carrying out killings and acts of brutality under the guise of jihad—holy struggle—saying that its "sacrifice" without legitimate cause, goals and intention "is not jihad at all, but rather, warmongering and criminality". It also accuses the group of instigating fitna—sedition—by instituting slavery under its rule in contravention of the anti-slavery consensus of the Islamic scholarly community. The group's persecution of Shia Muslims has also been condemned. The current Grand Imam of al-Azhar and former president of al-Azhar University, Ahmed el-Tayeb, has strongly condemned the Islamic State, stating that it is acting "under the guise of this holy religion and have given themselves the name 'Islamic State' in an attempt to export their false Islam". Citing the Quran, he stated: "The punishment for those who wage war against God and his Prophet and who strive to sow corruption on earth is death, crucifixion, the severing of hands and feet on opposite sides or banishment from the land. This is the disgrace for them in this world and in the hereafter, they will receive grievous torment." Although el-Tayeb has been criticised for not expressly stating that the Islamic State is heretical, the Ash'ari school of Islamic theology, to which el-Tayeb belongs, does not allow calling a person who follows the shahada an apostate. El-Tayeb has strongly come out against the practice of takfirism (declaring a Muslim an apostate), which is used by the Islamic State to "judge and accuse anyone who doesn't tow their line with apostasy and outside the realm of the faith" declaring "Jihad on peaceful Muslims" using "flawed interpretations of some Qur'anic texts, the prophet's Sunna, and the Imams' views believing incorrectly, that they are leaders of Muslim armies fighting infidel peoples, in unbelieving lands". In late December 2015, nearly 70,000 Indian Muslim clerics associated with the Indian Barelvi movement issued a fatwa condemning ISIL and similar organisations, saying they are "not Islamic organisations". Approximately 1.5 million Sunni Muslim followers of this movement have formally decried violent extremists. Mehdi Hasan, a political journalist in the UK, said in the New Statesman Whether Sunni or Shia, Salafi or Sufi, conservative or liberal, Muslims—and Muslim leaders—have almost unanimously condemned and denounced ISIL not merely as un-Islamic but actively anti-Islamic. Hassan Hassan, an analyst at the Delma Institute, wrote in The Guardian that because the Islamic State "bases its teachings on religious texts that mainstream Muslim clerics do not want to deal with head on, new recruits leave the camp feeling that they have stumbled on the true message of Islam". Theologian and Qatar-based TV broadcaster Yusuf al-Qaradawi stated: "[The] declaration issued by the Islamic State is void under sharia and has dangerous consequences for the Sunnis in Iraq and for the revolt in Syria", adding that the title of caliph can "only be given by the entire Muslim nation", not by a single group. He also stated on his official website "United Arab Emirates (UAE) and the leaders of Daesh (ISIS/ISIL) terrorist group are from one species and they are two sides of the same coin". In a similar vein, the Syrian Islamic scholar Muhammad al-Yaqoubi says, "[t]he followers of ISIS do not want to adhere to Islamic law but rather they want to twist Islamic law to conform to their fantasies. To this end, they pick and choose the evidences that corroborate their misguidance, despite being weak or abrogated." Academics Robyn Creswell and Bernard Haykel of The New Yorker have criticised ISIL's execution of Muslims for breach of traditional sharia law while violating it simultaneously themselves (encouraging women to emigrate to its territory, travelling without a Wali—male guardian—and in violation of his wishes). as well as its love of archaic imagery (horsemen and swords) while engaging in bid'ah (religious innovation) in establishing female religious police (known as Al-Khansaa Brigade). Two days after the beheading of Hervé Gourdel, hundreds of Muslims gathered in the Grand Mosque of Paris to show solidarity against the beheading. The protest was led by the leader of the French Council of the Muslim Faith, Dalil Boubakeur, and was joined by thousands of other Muslims around the country under the slogan "Not in my name".[better source needed] French president François Hollande said Gourdel's beheading was "cowardly" and "cruel", and confirmed that airstrikes would continue against ISIL in Iraq. Hollande also called for three days of national mourning, with flags flown at half-mast throughout the country and said that security would be increased throughout Paris.[better source needed] According to The New York Times, "All of the most influential jihadist theorists are criticising the Islamic State as deviant, calling its self-proclaimed caliphate null and void" and they have denounced it for its beheadings of journalists and aid workers. ISIL is widely denounced by a broad range of Islamic clerics, including Saudi and al-Qaeda-oriented clerics. Muhammad al-Yaqoubi states, "It is enough of a proof of the extreme ideology of ISIS that the top leaders of Salafi-Jihadism have disclaimed it." Other critics of ISIL's brand of Sunni Islam include Salafists who previously publicly supported jihadist groups such as al-Qaeda: for example, the Saudi government official Saleh Al-Fawzan, known for his extremist views, who claims that ISIL is a creation of "Zionists, Crusaders and Safavids", and the Jordanian-Palestinian writer Abu Muhammad al-Maqdisi, the former spiritual mentor to Abu Musab al-Zarqawi, who was released from prison in Jordan in June 2014 and accused ISIL of driving a wedge between Muslims. An Islamic Front sharia court judge in Aleppo, Mohamed Najeeb Bannan, stated: "The legal reference is the Islamic Sharia. The cases are different, from robberies to drug use, to moral crimes. It's our duty to look at any crime that comes to us... After the regime has fallen, we believe that the Muslim majority in Syria will ask for an Islamic state. Of course, it's very important to point out that some say the Islamic Sharia will cut off people's hands and heads, but it only applies to criminals. And to start off by killing, crucifying etc. That is not correct at all." In response to being asked what the difference between the Islamic Front's and ISIL's version of sharia would be, he said, "One of their mistakes is before the regime has fallen, and before they've established what in Sharia is called Tamkeen [having a stable state], they started applying Sharia, thinking God gave them permission to control the land and establish a Caliphate. This goes against the beliefs of religious scholars around the world. This is what [IS] did wrong. This is going to cause a lot of trouble. Anyone who opposes [IS] will be considered against Sharia and will be severely punished." Al-Qaeda and al-Nusra have been trying to take advantage of ISIL's rise, by attempting to present themselves as "moderate" compared to "extremist" ISIL, although they have the same aim of establishing sharia and a caliphate, but doing so in a more gradual manner. Al-Nusra has criticised the way in which ISIL fully and immediately institutes sharia in the areas that fall under its control, since it alienates people too much. It supports the gradual, slower approach favoured by al-Qaeda, preparing society to accept sharia and indoctrinating people through education before implementing the hudud aspects in sharia, which they believe supports punishments such as throwing homosexuals from the top of buildings, chopping limbs off, and public stoning. Al-Nusra and ISIL are both hostile towards the Druze. However, while al-Nusra has typically destroyed Druze shrines and pressured them to convert to Sunni Islam, ISIL regards the entire Druze community as a valid target for violence, as it does the Yazidis. In February 2014, Ayman al-Zawahiri, the leader of Al-Qaeda, announced that his group Al-Qaeda had cut ties with the Islamic State of Iraq and the Levant and denounced ISIL after being unable to reconcile a conflict between them and the al-Qaeda affiliate al-Nusra Front. In September 2015, Ayman al-Zawahiri called for consultation (shura) within the "prophetic method" to be used when establishing the caliphate, criticising al-Baghdadi for not following the required steps. Al-Zawahiri called upon ISIL members to close ranks and join al-Qaeda in fighting against Assad, the Shia, Russia, Europe, and America and to stop the infighting between jihadist groups. He called upon jihadists to establish Islamic entities in Egypt and the Levant, slowly implementing sharia before establishing a caliphate, and has called for violent assaults against America and the West. The Jaysh al-Islam group within the Islamic Front criticised ISIL, saying: "They killed the people of Islam and leave the idol worshippers ... They use the verses talking about the disbelievers and implement it on the Muslims". The main criticism of defectors from ISIL has been that the group is fighting and killing other Sunni Muslims, as opposed to just non-Sunnis being brutalised. In one case, a supposed defector from ISIL executed two activists of a Syrian opposition group in Turkey who had sheltered them. Literature scholar Ian Almond criticised the media commentators, the lack of balance in reporting, and the "way we are learning to talk about ISIS". While there was talk about 'radical evil' and 'radical Islam', Almond found it striking because "some of the most revered and oft-quoted figures in our Western political tradition have been capable of the most vicious acts of savagery—and yet all we ever hear about is how much the Middle East has to learn from us." Almond goes on to argue that Winston Churchill "wanted to gas women and children", that Ronald Reagan's Central American policies "disembowelled more children than ISIS", that President Barack Obama's "planes and drones have dropped bombs on as many schoolchildren as ISIS", that former secretary of state Madeleine Albright commented on the deaths of Iraqi children killed by sanctions, that Henry Kissinger and Margaret Thatcher "assisted in the torture and disappearance of thousands of Chilean students and labour activists... For anyone familiar with the history of both U.S. and European torture and murder over the past 150 years, it might not be all that hyperbolic to say that in ISIS, what we see more than anything else is a more expansive, explicit version of our own cruelties. In bombing ISIS and its would-be imperialism, we are really bombing a version of ourselves." Commentator Tom Engelhardt attributed the rise of ISIL and the destruction that followed to what he dubbed as America's drive to establish its own caliphate in the region. A leader article in the New Scientist magazine contextualised ISIL within the nation state construct. Although the group is described as medieval in the pejorative sense, "it is also hyper-modern, interested in few of the trappings of a conventional state apart from its own brutal brand of law enforcement. In fact, it is more of a network than a nation, having made canny use of social media to exert influence far beyond its geographical base." The United Nations Security Council in its Resolution 1267 (1999) described Osama bin Laden and his al-Qaeda associates as operators of a network of terrorist training camps. The UN's Al-Qaida Sanctions Committee first listed ISIL in its Sanctions List under the name "Al-Qaida in Iraq" on 18 October 2004, as an entity/group associated with al-Qaeda. On 2 June 2014, the group was added to its listing under the name "Islamic State in Iraq and the Levant". The European Union adopted the UN Sanctions List in 2002. Many world leaders and government spokespeople have called ISIL a terrorist group or banned it, without their countries having formally designated it as such. The following are examples: The Government of Germany banned ISIL in September 2014. Activities banned include donations to the group, recruiting fighters, holding ISIL meetings and distributing its propaganda, flying ISIL flags, wearing ISIL symbols and all ISIL activities. "The terror organisation Islamic State is a threat to public safety in Germany as well", said German politician Thomas de Maizière. He added, "Today's ban is directed solely against terrorists who abuse religion for their criminal goals." Being a member of ISIL is also illegal in accordance with § 129a and § 129b of the German criminal code. In October 2014, Switzerland banned ISIL's activities in the country, including propaganda and financial support of the fighters, with prison sentences as potential penalties. In mid-December 2014, India banned ISIL after the arrest of an operator of a pro-ISIL Twitter account.[better source needed] Pakistan designated ISIL as a banned organisation in late August 2015, under which all elements expressing sympathy for the group would be blacklisted and sanctioned. After its 2022 Ulema gathering, the Taliban banned all Afghans from associating with the local Khorasan Province branch of IS in July 2022, and labeled it a "false sect". Media sources worldwide have described ISIL as a terrorist organisation. Following the D-ISIS Ministerial in June 2023, Secretary Blinken announced Abdallah Makki Muslih al-Rufay'i and Abu Bakr ibn Muhammad ibn 'Ali al-Mainuki, as terrorists under Executive Order 13224. By 2014, ISIL was increasingly being viewed as a militia in addition to a terrorist group and a cult. As major Iraqi cities fell to ISIL in June 2014, Jessica Lewis, a former US Army intelligence officer at the Institute for the Study of War, described ISIL at that time as not a terrorism problem anymore, [but rather] an army on the move in Iraq and Syria, and they are taking terrain. They have shadow governments in and around Baghdad, and they have an aspirational goal to govern. I don't know whether they want to control Baghdad, or if they want to destroy the functions of the Iraqi state, but either way the outcome will be disastrous for Iraq. Lewis has called ISIL: An advanced military leadership. They have incredible command and control and they have a sophisticated reporting mechanism from the field that can relay tactics and directives up and down the line. They are well-financed, and they have big sources of manpower, not just the foreign fighters, but also prisoner escapees. Former US Defense Secretary Chuck Hagel saw an "imminent threat to every interest we have", but former top counter-terrorism adviser Daniel Benjamin derided such talk as a "farce" that panics the public. Writing for The Guardian, Pankaj Mishra rejects the idea that the group is a resurgence of medieval Islam, saying instead: In actuality, ISIS is the canniest of all traders in the flourishing international economy of disaffection: the most resourceful among all those who offer the security of collective identity to isolated and fearful individuals. It promises, along with others who retail racial, national and religious supremacy, to release the anxiety and frustrations of the private life into the violence of the global. On 28 January 2017, U.S. President Donald Trump issued a National Security Presidential Memorandum that called for a comprehensive plan to destroy ISIL to be formulated by the Defense Department within 30 days. Supporters A United Nations report from May 2015[update] showed that 25,000 "foreign terrorist fighters" from 100 countries had joined "Islamist" groups, many of them working for IS or al-Qaeda. According to a June 2015 Reuters report that cited "jihadist ideologues" as a source, 90% of IS's fighters in Iraq were Iraqi, and 70% of its fighters in Syria were Syrian. The article stated that the group had 40,000 fighters and 60,000 supporters across its two primary strongholds in Iraq and Syria. According to scholar Fawaz Gerges writing in ISIS: A History, some "30 percent of the senior figures" in IS's military command were former army and police officers from the disbanded Iraqi security forces, turned towards Sunni Islamism and drawn to IS by the US de-Ba'athification policy following the U.S. invasion of Iraq. A 2014 analysis of 2,195,000 Arabic-language social media posts cited by The Guardian had 47% of the postings from Qatar, 35% from Pakistan, 31% from Belgium and almost 24% from the UK classified as supportive of IS. According to a 2015 poll by Pew Research Center, Muslim populations of various Muslim-majority countries have overwhelmingly negative views of IS, with the highest percentage of those expressing favourable views not exceeding 14%. In most of these countries, concerns about Islamic extremism have been growing. There is a large amount of IS supporters online (On apps such as Discord, Telegram, among several other online forums). In 2024, at least 10,000 IS fighters were still active in Syria, according to estimates by the Kurdish-led SDF. As of 2025, approximately 10,000 suspected IS fighters and their supporters were being held in Syrian detention centres, and tens of thousands of their wives and children were living in secure camps. In January 2026, a northeastern Syria offensive conducted by the Syrian transitional government against the Kurdish-led Syrian Democratic Forces (SDF) led to a significant security vacuum, resulting in the escape and mass transfer of thousands of Islamic State detainees. Following the SDF's withdrawal from key facilities such as the al-Hawl and al-Shaddadi prisons, the U.S. military began relocating up to 9,000 detainees to Iraq to prevent a resurgence of IS, while Syrian government forces assumed control of several major detention centers, including al-Aqtan prison in Raqqa. Countries and groups at war with IS IS's claims to territory have brought it into armed conflict with many governments, militias and other armed groups. International rejection of IS as a terrorist entity and rejection of its claim to even exist have placed it in conflict with countries around the world. The Global Coalition to Counter the Islamic State of Iraq and the Levant (ISIL), also referred to as the Counter-ISIL Coalition or Counter-DAESH Coalition, is a US-led group of nations and non-state actors that have committed to "work together under a common, multifaceted, and long-term strategy to degrade and defeat ISIL/Daesh". According to a joint statement issued by 59 national governments and the European Union on 3 December 2014, participants in the Counter-ISIL Coalition are focused on multiple lines of effort: Operation Inherent Resolve is the operational name given by the US to military operations against ISIL and Syrian al-Qaeda affiliates. Combined Joint Task Force – Operation Inherent Resolve (CJTF–OIR) is co-ordinating the military portion of the response. The Arab League, European Union, NATO, and GCC are part of the Counter-ISIL Coalition: According to the Pentagon, by December 2017 over 80,000 ISIL fighters had been killed in Iraq and Syria by CJTF-OIR airstrikes. By then the coalition had flown over 170,000 sorties, 75–80% of combat sorties were conducted by the military of the United States, with the other 20–25% by Australia, Canada, Denmark, France, Jordan, Belgium, the Netherlands, Saudi Arabia, Turkey, the United Arab Emirates, and the United Kingdom. According to the UK-based monitoring group Airwars, the air strikes and artillery of US-led coalition killed as many as 6,000 civilians in Iraq and Syria by the end of 2017. Lebanon, which the U.S. considers part of the Global Coalition, fought off several incursions by ISIL, with the largest engagements taking place from June 2014 to August 2017, when several thousand ISIL fighters invaded from Syria and occupied Lebanese territory. The U.S. and UK-backed Lebanese Army succeeded in repulsing this invasion, killing or capturing over 1,200 ISIL fighters in the process. On 21 December 2019, over 33 Islamist militants were killed in Mali by French forces using attack helicopters, drones and ground troops, alongside the border with Mauritania, where an Al-Qaeda-linked group operates. Iran – military advisors, arms supplier, training, ground troops in Iraq and Syria, and air power in Syria, beside Iranian borders (see Iranian intervention in Iraq and Iranian intervention in the Syrian civil war) Russia – arms supplier to Iraqi and Syrian governments. Security operations within state borders in 2015. Airstrikes in Syria (see Russian military intervention in the Syrian Civil War). Azerbaijan – security operations within state borders Pakistan – Military deployment over Saudi Arabia–Iraq border. Arresting ISIL figures in Pakistan and security operations within state borders (see Insurgency in Khyber Pakhtunkhwa, Insurgency in Balochistan, Islamic State – Khorasan Province, and Islamic State – Pakistan Province) Yemen (Supreme Political Council) Afghanistan – security operations within state borders (see Islamic State–Taliban conflict) Al-Nusra Front is a branch of al-Qaeda operating in Syria. Al-Nusra has launched many attacks and bombings, mostly against targets affiliated with or supportive of the Syrian government. There have been media reports that many of al-Nusra's foreign fighters have left to join al-Baghdadi's ISIL. In February 2014, after continued tensions, al-Qaeda publicly disavowed any relations with ISIL. However, ISIL and al-Nusra Front still cooperate with each other occasionally when they fight against the Syrian government. The two groups [ISIL and al-Nusra] share a nihilistic worldview, a loathing for modernity, and for the West. They subscribe to the same perverted interpretations of Islam. Other common traits include a penchant for suicide attacks, and sophisticated exploitation of the internet and social media. Like ISIL, several Al Qaeda franchises are interested in taking and holding territory; AQAP has been much less successful at it. The main differences between Al Qaeda and ISIL are largely political—and personal. Over the past decade, Al Qaeda has twice embraced ISIL (and its previous manifestations) as brothers-in-arms. — Bobby Ghosh, "ISIL and Al Qaeda: Terror's frenemies", Quartz On 10 September 2015, an audio message was released by al-Qaeda's leader Ayman al-Zawahiri criticising ISIL's self-proclaimed caliphate and accusing it of "sedition". This was described by some media outlets as a "declaration of war". However, although al-Zawahiri denied ISIL's legitimacy, he suggested that there was still room for cooperation against common enemies, and said that if he were in Iraq, he would fight alongside ISIL. Human rights abuse and war crime findings The Islamic State has committed or been widely accused of committing war crimes, crimes against humanity, and of human rights abuses, including systematic rape and other forms of sexual violence against both males and females, mass killing of prisoners of war, summary executions including the Camp Speicher massacre, public floggings, beheadings, politically motivated assassinations of judges; public officials; members of the security forces and others, and terrorising residents of Derna, Libya among others. ISIL members were also reported to perform human sacrifices, despite the act being forbidden in Islam. Sarah Leah Watson, Director of HRW Middle East and North Africa, said: "Commanders should understand that they may face domestic or international prosecution for the grave rights abuses their forces are committing." In July 2014, the BBC reported the United Nations' chief investigator as stating: "Fighters from the Islamic State in Iraq and the Levant (ISIL) may be added to a list of war crimes suspects in Syria." The United Nations Commission on Human Rights has stated that the group "seeks to subjugate civilians under its control and dominate every aspect of their lives through terror, indoctrination, and the provision of services to those who obey". According to the Iraq Body Count project, the Islamic State's fighters killed a minimum of 25,645 Iraqi civilians from 2014 to 2016. Explanatory notes References General and cited references Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Rebecca_(biblical_figure)] | [TOKENS: 3529] |
Contents Rebecca (biblical figure) Rebecca or Rebekah[a] (/rɪˈbɛkə/) appears in the Hebrew Bible as the wife of Isaac and the mother of Jacob and Esau. According to biblical tradition, Rebecca's father was Bethuel the Aramean from Paddan Aram, also called Aram-Naharaim. Rebecca's brother was Laban the Aramean, and she was the granddaughter of Milcah and Nahor, the brother of Abraham. Rebecca and Isaac were one of the four couples that some believe are buried in the Cave of the Patriarchs, the other three being Adam and Eve, Abraham and Sarah, and Jacob and Leah. Most scholars have considered Rebecca's historicity uncertain. Early life After the Binding of Isaac, Sarah died. After taking care of her burial, Abraham went about finding a wife for his son Isaac, who was already 37 years old. He commanded his servant (whom the Torah commentators identify as Eliezer of Damascus) to journey to Aram Naharaim to select a bride from his own family, rather than engage Isaac to a local Canaanite girl. Abraham sent along expensive jewelry, clothing and dainties as gifts to the bride and her family. If the girl had refused to follow him, Abraham stated that Eliezer would be absolved of his responsibility. The servant devised a test in order to find the right wife for Isaac. As he stood at the central well in Aram-Naharaim, the city of Nahor, with his men and ten camels laden with goods, he prayed to God: Let the maiden to whom I say, 'Please, lower your jar that I may drink,' and who replies, 'Drink, and I will also water your camels'—let her be the one whom You have decreed for Your servant Isaac. Thereby shall I know that You have dealt graciously with my master. To his surprise, a young girl immediately came out and offered to draw water for him to drink, as well as water to fill the troughs for all his camels. Rebecca continued to draw water until all the camels were sated, proving her kind and generous nature and her suitability for entering Abraham's household. The servant immediately gave her a golden necklace (Septuagint translation) or nose ring (Masoretic translation) and two golden bracelets (Genesis 24:22, Genesis 24:47), which Rebecca hurried to show her mother. Seeing the jewelry, Rebecca's brother Laban ran out to greet the guest and bring him inside. The servant recounted the oath he made to Abraham and all the details of his trip to and meeting with Rebecca in fine detail, after which her brother Laban and her father Bethuel agreed that she could return with him. After hosting the party overnight, the family tried to keep Rebecca with them longer. The servant insisted that they ask the girl herself, and she agreed to go immediately. Her family sent her off with her nurse, Deborah (according to Rashi), and blessed her, "Our sister, may you come to be thousands of myriads, and may your offspring inherit the gate of its foes." As Rebecca and her entourage approached Abraham's home, they spied Isaac from a distance in the fields of Beer-lahai-roi. The Talmud and the Midrash explain that Isaac was praying, as he instituted Mincha, the afternoon prayer. Seeing such a spiritually exalted man, Rebecca immediately dismounted from her camel and asked the accompanying servant who he was. When she heard that this was her future husband, she modestly covered herself with a veil. Isaac brought her into the tent of his deceased mother Sarah, married her, and loved her. According to Rashi, the three miracles that characterized Sarah's tent while she was alive, and that disappeared with her death, reappeared when Rebecca entered the tent. These were: A lamp burned in her tent from Shabbat eve to Shabbat eve, there was a blessing in her dough, and a cloud hovered over her tent (symbolizing the Divine Presence). Some of the events leading up to the marriage of Isaac and Rebecca have been institutionalized in the traditional Jewish wedding ceremony. Before the bride and bridegroom stand under the chuppah, they take part in a special ceremony called badeken (veiling). The bridegroom is led to the bride by two escorts and, seeing her, covers her face with a veil, like the way Rebecca covered her face before marrying Isaac. Then the bridegroom (or the father of the bride, or the officiating rabbi) recites the same blessing over the bride that Rebecca's family recited over her, "Our sister, may you come to be thousands of myriads, and may your offspring inherit the gate of its foes." Marriage and motherhood According to the traditional counting cited by Rashi, Isaac was 37 years old at the time of the Binding of Isaac. The reasoning for that age is that Sarah, who gave birth to Isaac when she was 90, died after the binding when she was 127 years old, making Isaac around 37 at that time. According to Seder Olam Rabbah and Targum Pseudo-Jonathan, Rebecca was 3 at the time of her marriage, a number which is accepted by most medieval rabbinical commentators, including Rashi. However, Isaiah di Trani and Hezekiah ben Manoah calculate that she was 14. Twenty years elapsed before they had children; throughout that time, both Isaac and Rebecca prayed fervently to God for offspring. God eventually answered Isaac's prayers and Rebecca conceived. Rebecca was extremely uncomfortable during her pregnancy and went to inquire of God why she was suffering so. According to the Midrash, whenever she would pass a house of Torah study, Jacob would struggle to come out; whenever she would pass a house of idolatry, Esau would agitate to come out. Thinking that she was carrying one baby who was displaying conflicting propensities, Rebecca sought enlightenment at the yeshiva of Shem and Eber. There she received the prophecy that twins were fighting in her womb and would continue to fight all their lives. The prophecy also said that the older would serve the younger; its statement, "One people will be stronger than the other" has been taken to mean that the two nations will never gain power simultaneously; when one falls, the other will rise, and vice versa. According to tradition, Rebecca did not share the prophecy with her husband. When the time came for Rebecca to give birth, the first child to come out emerged red and hairy all over, with his heel grasped by the hand of the second to come out. Onlookers named the first עשו, Esau ('Esav or 'Esaw, meaning either "rough", "sensibly felt", "handled", from Hebrew: עשה, 'asah, "do" or "make"; or "completely developed", from Hebrew: עשוי, 'assui, since Esau had as much hair as a child who was much older) The second was named יעקב, Jacob (Ya'aqob or Ya'aqov, meaning "heel-catcher", "supplanter", "leg-puller", "he who follows upon the heels of one", from Hebrew: עקב, 'aqab or 'aqav, "seize by the heel", "circumvent", "restrain", a wordplay upon Hebrew: עקבה, 'iqqebah or 'iqqbah, "heel"). The Bible states that Isaac was sixty years old when the twins were born. The Midrash says that as boys, people did not notice much difference between them. When they reached the age of 13, Jacob busied himself in the house of study, while Esau busied himself with idolatry. The descriptions of the two young men hint at their opposing spiritual natures: "The lads grew up and Esau became one who knows hunting, a man of the field; but Jacob was a wholesome man, abiding in tents". The description of Esau as a "hunter" hints to his skill of trapping his father with his mouth; for example, he would ask Isaac whether tithes should be taken from salt and straw, making his father think he was scrupulous in keeping the mitzvot. Scripture notes that the attitudes of their parents toward the boys differed: "Isaac loved Esau because he did eat of hunting, but Rebecca loved Jacob". According to the Talmud, immediately after Abraham died, Jacob prepared a lentil stew as a traditional mourner's meal for his father, Isaac. The Hebrew Bible states that Esau, returning famished from the fields, begged Jacob to give him some of the stew. (Esau referred to the dish as "that red, red stuff", giving rise to his nickname, Hebrew: אדום ('Edom, meaning "Red")). Jacob offered to give Esau a bowl of stew in exchange for his birthright (the right to be recognized as firstborn), and Esau agreed. The Talmudic dating indicates both men were 15 years old at the time. At a later time, a famine struck the land of Israel and Isaac moved his family, upon God's command, to Gerar, which was ruled by Abimelech, king of the Philistines. Like Abraham before him, who called Sarah his "sister" rather than his "wife" so that the Egyptians would not kill him and take his wife, Isaac told the people of Gerar that Rebecca was his sister. She was not molested, but one day Abimelech looked through the window and saw Isaac "sporting" (a euphemism for sexual play) with her. Abimelech called Isaac on his lie, and then warned others not to touch Rebecca. Eventually Isaac parted from Abimelech in peace. At the age of 40 (the same age his father had been when he married), Esau took two Hittite wives, Judith the daughter of Beeri, and Basemath the daughter of Elon, who vexed Isaac and Rebecca to no end, as these women were also idol-worshippers. One reason why Isaac became blind in his old age was due to the smoke of the incense that these women offered to their idols. Deception of Isaac Isaac became blind in his old age and decided to bestow the blessing of the firstborn upon Esau. According to the Midrash, Isaac had reached the age of 132, five years past the age of his mother, Sarah, had been at the time of her death. According to Genesis, Isaac had reached the age of 137. At this time, the Sages state that one should begin to think he might not exceed the age of whichever parent died first. Isaac therefore sent Esau out to the fields to trap and cook a piece of game for him, so that he could eat it and bless Esau before he died. Rebecca overheard this conversation and realized that Isaac's blessings should go to Jacob, since she was told before the twins' birth that the older son would serve the younger. She therefore ordered Jacob to bring her two goats from the flock, which she cooked in the way Isaac loved, and had him bring them to his father in place of Esau. When Jacob protested that his father would recognize the deception and curse him as soon as he felt him, since Esau was hairy and Jacob smooth-skinned, Rebecca said that the curse would be on her instead. Before she sent Jacob to his father, she dressed him in Esau's garments and laid goatskins on his arms and neck to simulate hairy skin. Thus disguised, Jacob entered his father's room. Surprised to perceive that Esau was back so soon, Isaac asked how it could be that the hunt went so quickly. Jacob responded, "Because the LORD your God arranged it for me"; Rashi (on Genesis 52:46) says Isaac's suspicions were aroused because Esau never used the personal name of God. Isaac demanded that Jacob come close so he could feel him, but the goatskins felt just like Esau's hairy skin. Confused, Isaac exclaimed, "The voice is the voice of Jacob, but the hands are the hands of Esau!" (27:22). Still trying to get at the truth, Isaac asked him point-blank, "Are you really my son Esau?" and Jacob answered simply, "I am" (which can be taken as "I am me", not "I am Esau"). Isaac proceeded to eat the food and to drink the wine that Jacob gave him, and then he blessed him with the dew of the heavens, the fatness of the earth, and rulership over many nations as well as his own brother. Jacob had scarcely left the room when Esau returned from the hunt to receive the blessing. The realization that he has been deceived shocks Isaac, yet he acknowledged that Jacob received the blessings as sworn, by adding, "Indeed, he will be [or remain] blessed!" (52:8). Rashi explains that Isaac smelled the heavenly scent of Gan Eden (Paradise) when Jacob entered his room. As a contrast, Isaac perceived Gehenna opening beneath Esau when the latter entered the room, showing Isaac that he had been deceived all along by Esau's show of piety. Esau was heartbroken by the deception, and begged for his own blessing. Having made Jacob a ruler over his brothers, Isaac could only promise, "By thy sword thou shalt live, and shalt serve thy brother; yet it shall come to pass when thou shalt have the dominion, that thou shalt cast off his yoke from off thy neck" (Gen 27:40). Esau was filled with hatred toward Jacob for taking away both his birthright and his blessing. He vowed to himself to kill Jacob as soon as Isaac died. Here again, Rebecca prophetically perceived his murderous intentions and ordered Jacob to travel to her brother Laban's house in Haran, until Esau's anger subsided. She then convinced Isaac to send Jacob away, by telling him that she despaired of him marrying a local girl from the idol-worshipping families of Canaan (as Esau had done). After Isaac sent Jacob away (to find a wife), Esau realized that his own Canaanite wives were evil in his father's eyes. Esau therefore took Mahalath, a daughter of Isaac's half-brother Ishmael, as another wife. Death and burial Jacob lived with Laban for twenty years (Gen. 31:41), marrying Laban's two daughters and two maidservants. He returned to Canaan with his large family, servants, and possessions. As he did, Deborah (Rebecca's nurse) died and was buried at a place that Jacob calls Alon Bachuth (אלון בכות), "Tree of Weepings" (Gen. 35:8). According to the Midrash, the plural form of the word "weeping" indicates a double sorrow, implying that Rebecca also died at this time. Rebecca was buried in the Cave of Machpelah near Mamre, in the land of Canaan (Gen. 49:31). According to the Talmud, the Torah's explicit dating of the life of Ishmael helps to date various events in Jacob's life and, by implication, the age of Rebecca at her death. Ishmael was born when Abraham was 86 years old (Gen. 16:16) and died at the age of 137 (Gen. 25:17). Isaac was born when Abraham was 100 (Gen. 21:5); at that time Ishmael was 14. Jacob and Esau were born when Isaac was 60 (Gen. 25:26); at that time Ishmael was 74. Right after Jacob receives the blessings and flees to Laban, the Torah states that Esau married "Mahalat, the daughter of Ishmael, son of Abraham, sister of Nebaiot" (Gen. 28:9), on which Rashi, quoting Megillah 17a, notes that Ishmael died between the engagement and wedding, so the girl's brother gave her away. If Ishmael was 137 at the time of his death, this means that Jacob and Esau were 63 at the time of the blessings. The Talmud adds that Jacob spent 14 years in the yeshiva of Shem and Eber before proceeding to Laban, arriving when he was 77. Rebecca's death after Jacob's 20 years with Laban indicates that Jacob was 97 when his mother died and Rebecca was either 120 or 134 (based on different Midrashim mentioned earlier about her age at marriage). Gallery See also Explanatory notes References External links |
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