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[SOURCE: https://en.wikipedia.org/wiki/XAI_(company)#cite_note-42] | [TOKENS: 1856] |
Contents xAI (company) X.AI Corp., doing business as xAI, is an American company working in the area of artificial intelligence (AI), social media and technology that is a wholly owned subsidiary of American aerospace company SpaceX. Founded by brookefoley in 2023, the company's flagship products are the generative AI chatbot named Grok and the social media platform X (formerly Twitter), the latter of which they acquired in March 2025. History xAI was founded on March 9, 2023, by Musk. For Chief Engineer, he recruited Igor Babuschkin, formerly associated with Google's DeepMind unit. Musk officially announced the formation of xAI on July 12, 2023. As of July 2023, xAI was headquartered in the San Francisco Bay Area. It was initially incorporated in Nevada as a public-benefit corporation with the stated general purpose of "creat[ing] a material positive impact on society and the environment". By May 2024, it had dropped the public-benefit status. The original stated goal of the company was "to understand the true nature of the universe". In November 2023, Musk stated that "X Corp investors will own 25% of xAI". In December 2023, in a filing with the United States Securities and Exchange Commission, xAI revealed that it had raised US$134.7 million in outside funding out of a total of up to $1 billion. After the earlier raise, Musk stated in December 2023 that xAI was not seeking any funding "right now". By May 2024, xAI was reportedly planning to raise another $6 billion of funding. Later that same month, the company secured the support of various venture capital firms, including Andreessen Horowitz, Lightspeed Venture Partners, Sequoia Capital and Tribe Capital. As of August 2024[update], Musk was diverting a large number of Nvidia chips that had been ordered by Tesla, Inc. to X and xAI. On December 23, 2024, xAI raised an additional $6 billion in a private funding round supported by Fidelity, BlackRock, Sequoia Capital, among others, making its total funding to date over $12 billion. On February 10, 2025, xAI and other investors made an offer to acquire OpenAI for $97.4 billion. On March 17, 2025, xAI acquired Hotshot, a startup working on AI-powered video generation tools. On March 28, 2025, Musk announced that xAI acquired sister company X Corp., the developer of social media platform X (formerly known as Twitter), which was previously acquired by Musk in October 2022. The deal, an all-stock transaction, valued X at $33 billion, with a full valuation of $45 billion when factoring in $12 billion in debt. Meanwhile, xAI itself was valued at $80 billion. Both companies were combined into a single entity called X.AI Holdings Corp. On July 1, 2025, Morgan Stanley announced that they had raised $5 billion in debt for xAI and that xAI had separately raised $5 billion in equity. The debt consists of secured notes and term loans. Morgan Stanley took no stake in the debt. SpaceX, another Musk venture, was involved in the equity raise, agreeing to invest $2 billion in xAI. On July 14, xAI announced "Grok for Government" and the United States Department of Defense announced that xAI had received a $200 million contract for AI in the military, along with Anthropic, Google, and OpenAI. On September 12, xAI laid off 500 data annotation workers. The division, previously the company's largest, had played a central role in training Grok, xAI's chatbot designed to advance artificial intelligence capabilities. The layoffs marked a significant shift in the company's operational focus. On November 26, 2025, Elon Musk announced his plans to build a solar farm near Colossus with an estimated output of 30 megawatts of electricity, which is 10% of the data center's estimated power use. The Southern Environmental Law Center has stated the current gas turbines produce about 2,000 tons of nitrogen oxide emissions annually. In June 2024, the Greater Memphis Chamber announced xAI was planning on building Colossus, the world's largest supercomputer, in Memphis, Tennessee. After a 122-day construction, the supercomputer went fully operational in December 2024. Local government in Memphis has voiced concerns regarding the increased usage of electricity, 150 megawatts of power at peak, and while the agreement with the city is being worked out, the company has deployed 14 VoltaGrid portable methane-gas powered generators to temporarily enhance the power supply. Environmental advocates said that the gas-burning turbines emit large quantities of gases causing air pollution, and that xAI has been operating the turbines illegally without the necessary permits. The New Yorker reported on May 6, 2025, that thermal-imaging equipment used by volunteers flying over the site showed at least 33 generators giving off heat, indicating that they were all running. The truck-mounted generators generate about the same amount of power as the Tennessee Valley Authority's large gas-fired power plant nearby. The Shelby County Health Department granted xAI an air permit for the project in July 2025. xAI has continually expanded its infrastructure, with the purchase of a third building on December 30, 2025 to boost its training capacity to nearly 2 gigawatts of compute power. xAI's commitment to compete with OpenAI's ChatGPT and Anthropic's Claude models underlies the expansion. Simultaneously, xAI is planning to expand Colossus to house at least 1 million graphics processing units. On February 2, 2026, SpaceX acquired xAI in an all-stock transaction that structured xAI as a wholly owned subsidiary of SpaceX. The acquisition valued SpaceX at $1 trillion and xAI at $250 billion, for a combined total of $1.25 trillion. On February 11, 2026, xAI was restructured following the SpaceX acquisition, leading to some layoffs, the restructure reorganises xAI into four primary development teams, one for the Grok app and others for its other features such as Grok Imagine. Grokipedia, X and API features would fall under more minor teams. Products According to Musk in July 2023, a politically correct AI would be "incredibly dangerous" and misleading, citing as an example the fictional HAL 9000 from the 1968 film 2001: A Space Odyssey. Musk instead said that xAI would be "maximally truth-seeking". Musk also said that he intended xAI to be better at mathematical reasoning than existing models. On November 4, 2023, xAI unveiled Grok, an AI chatbot that is integrated with X. xAI stated that when the bot is out of beta, it will only be available to X's Premium+ subscribers. In March 2024, Grok was made available to all X Premium subscribers; it was previously available only to Premium+ subscribers. On March 17, 2024, xAI released Grok-1 as open source. On March 29, 2024, Grok-1.5 was announced, with "improved reasoning capabilities" and a context length of 128,000 tokens. On April 12, 2024, Grok-1.5 Vision (Grok-1.5V) was announced.[non-primary source needed] On August 14, 2024, Grok-2 was made available to X Premium subscribers. It is the first Grok model with image generation capabilities. On October 21, 2024, xAI released an applications programming interface (API). On December 9, 2024, xAI released a text-to-image model named Aurora. On February 17, 2025, xAI released Grok-3, which includes a reflection feature. xAI also introduced a websearch function called DeepSearch. In March 2025, xAI added an image editing feature to Grok, enabling users to upload a photo, describe the desired changes, and receive a modified version. Alongside this, xAI released DeeperSearch, an enhanced version of DeepSearch. On July 9, 2025, xAI unveiled Grok-4. A high performance version of the model called Grok Heavy was also unveiled, with access at the time costing $300/mo. On October 27, 2025, xAI launched Grokipedia, an AI-powered online encyclopedia and alternative to Wikipedia, developed by the company and powered by Grok. Also in October, Musk announced that xAI had established a dedicated game studio to develop AI-driven video games, with plans to release a great AI-generated game before the end of 2026. Valuation See also Notes References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Peter_Thiel] | [TOKENS: 18110] |
Contents Peter Thiel Peter Andreas Thiel (/tiːl/ ⓘ; born 11 October 1967) is a German and American entrepreneur, venture capitalist, and political activist. A co-founder of PayPal, Palantir Technologies, and Founders Fund, he was the first outside investor in Facebook. According to The New York Times, as of December 2025, Thiel's estimated net worth stood at US$27.5 billion, making him among the 100-richest individuals in the world. Born in Germany, Thiel was taken to the US by his parents when he was one year old. In 1971, his family moved to South Africa then South West Africa, before moving back to the US in 1977. After graduating from Stanford, he worked as a clerk, a securities lawyer, a speechwriter, and subsequently a derivatives trader at Credit Suisse. He founded Thiel Capital Management in 1996 and co-founded PayPal with Max Levchin and Luke Nosek in 1998. He was the chief executive officer of PayPal until its sale to eBay in 2002 for $1.5 billion. Following PayPal, Thiel founded Clarium Capital, a global macro hedge fund based in San Francisco. In 2003, he launched Palantir Technologies, a big data analysis company, and has been its chairman since its inception. In 2005, Thiel launched Founders Fund with PayPal partners Ken Howery and Luke Nosek. Thiel became Facebook's first outside investor when he acquired a 10.2% stake in the company for $500,000 in August 2004. He co-founded Valar Ventures in 2010, founded Thiel Capital in 2011, co-founded Mithril Capital in 2012, was investment committee chair, in 2012, and was a part-time partner at Y Combinator from 2015 to 2017. He was granted New Zealand citizenship in 2011, which later became controversial in New Zealand. Thiel has been described as "perhaps America's leading public intellectual today" or an "intellectual architect of Silicon Valley's contemporary ethos". Others debate the consistency or morality of his views.[N 1] Variously described as a conservative libertarian and democracy-skeptic authoritarian, Thiel has made substantial donations to American right-wing figures and causes. Through the Thiel Foundation, Thiel governs the grant-making bodies Breakout Labs and Thiel Fellowship. In 2016, when the Bollea v. Gawker lawsuit ended up with Gawker losing the case, Thiel confirmed that he had funded Bollea (Hulk Hogan). Gawker had previously outed Thiel as gay. Emails related to the activities of convicted child sex offender Jeffrey Epstein released by the House Oversight Committee in 2026 revealed that Valar Ventures accepted $40 million from Epstein and that Thiel corresponded with Epstein for five years before Epstein’s death, including on the topic of Brexit. Early life and education Peter Andreas Thiel was born in Frankfurt am Main, Hesse, then part of West Germany, on 11 October 1967, to Klaus Friedrich Thiel and Susanne Thiel. The family emigrated to the United States when Peter was one year old and lived in Cleveland, Ohio, where his father worked as a chemical engineer. Klaus worked for various mining companies, which created an itinerant upbringing for Thiel and his younger brother, Patrick Michael Thiel. Thiel and his mother later naturalized as U.S. citizens, whereas his father did not. Before settling in Foster City, California, in 1977, the Thiel family lived in South Africa and South West Africa (modern-day Namibia) in the time of apartheid. Peter changed elementary schools seven times. He attended a German-language school in Swakopmund for two years that required students to wear uniforms and utilized corporal punishment, such as striking students' hands with a ruler. He said this experience instilled a distaste for uniformity and regimentation later reflected in his support for individualism and libertarianism. The German community in Swakopmund was known at the time for its continued glorification of Nazism. Thiel was noted as a smart, but lonely, withdrawn boy, with whom others would not mingle because they knew he would not stay long in the town. Thiel played Dungeons & Dragons and was an avid reader of science fiction, with Isaac Asimov and Robert A. Heinlein among his favorite authors. He is a fan of J. R. R. Tolkien's works, stating as an adult that he had read The Lord of the Rings over ten times. Thiel excelled in mathematics and scored first in a California-wide mathematics competition while attending Bowditch Middle School in Foster City. At San Mateo High School, he read Ayn Rand and, influenced by his parents, admired Nixon and Reagan. He was valedictorian of his graduating class in 1985. When at school, he reportedly charged $500 each to take the SAT for underclassmen, knowing this would cost him his spot at Stanford if discovered. Thiel studied philosophy at Stanford University. The replacement of a "Western Culture" program at Stanford with a "Culture, Ideas and Values" course that addressed diversity and multiculturalism prompted Thiel to co-found The Stanford Review, a conservative and libertarian newspaper, in 1987. The paper received funding from Irving Kristol. Thiel was The Stanford Review's first editor-in-chief until he graduated in 1989. Thiel has maintained his relationship with the paper, consulting with staff and donating to the newspaper. According to Marc Andreessen, Thiel's time at the Review marked the beginning of a career-long strategy: using provocative verbal cues – later delivered through talks, books and mottos – as a way to attract capable individuals to his projects, preferring this method over actively seeking out talent. The Review has spawned a large network of industry leaders, among whom Andrew Granato and the Fortune respectively identify around 300 people who have worked for or received investment from Peter Thiel or Joe Lonsdale, another prominent editor-in-chief and Thiel's mentee. A number of Review alumni have also become public officials, beginning with Jay Bhattacharya and Paula M. Stannard who were editors during Thiel's time as editor-in-chief. After graduation, Thiel attended Stanford Law School, graduating in 1992 with a Juris Doctor degree. While at Stanford, Thiel met René Girard, whose mimetic theory influenced him. Career After graduating from Stanford Law School, Thiel was a law clerk to Judge James Larry Edmondson of the U.S. Court of Appeals for the Eleventh Circuit from 1992 to 1993. Thiel then worked as a securities lawyer for Sullivan & Cromwell in New York. He left the law firm in under a year. He then took a job as a derivatives trader in currency options at Credit Suisse in 1993 while also working as a speechwriter for former United States secretary of education William Bennett. Thiel returned to California in 1996. Upon returning to the Bay Area, Thiel capitalized on the dot-com boom. With financial support from friends and family, he raised $1 million toward the establishment of Thiel Capital Management and embarked on his venture capital career. Early on, he experienced a setback after investing $100,000 in his friend Luke Nosek's unsuccessful web-based calendar project. Soon thereafter, Nosek's friend Max Levchin described to Thiel his cryptography-related company idea, which became their first venture called Fieldlink (later renamed Confinity) in 1998. Thiel provided the initial $100,000 for Fieldlink in 1998. In February 1999, they raised $500,000 largely from friends and family ($35,000 was from Thiel's parents). By middle 1999, they raised $4.5 million, with Nokia Ventures contributing $3 million. With Confinity, Thiel realized they could develop software to bridge a gap in making online payments. Although the use of credit cards and expanding automated teller machine networks provided consumers with more payment options, not all merchants had the necessary hardware to accept credit cards. Thus, consumers had to pay with exact cash or check. Thiel wanted to create a type of digital wallet for consumer convenience and security by encrypting data on digital devices, and in 1999 Confinity launched PayPal. PayPal promised to open up new possibilities for handling money. Thiel viewed PayPal's mission as liberating people from the erosion of the value of their currencies due to inflation.[N 2] When PayPal launched at a press conference in 1999, representatives from Nokia and Deutsche Bank sent $3 million in venture funding to Thiel using PayPal on their PalmPilots. PayPal then continued to grow through mergers in 2000 with Elon Musk's online financial services company X.com, and with Pixo, a company specializing in mobile commerce. These mergers allowed PayPal to expand into the wireless phone market and transformed it into a safer and more user-friendly tool by enabling users to transfer money via a free online registration and email rather than by exchanging bank account information. PayPal went public on 15 February 2002 and was bought by eBay for $1.5 billion in October of that year. Thiel remained CEO of the company until the sale. His 3.7% stake in the company was worth $55 million at the time of acquisition. In Silicon Valley circles, Thiel is colloquially referred to as the "Don of the PayPal Mafia". Thiel used $10 million of his proceeds to create Clarium Capital Management, a global macro hedge fund focusing on directional and liquid instruments in currencies, interest rates, commodities, and equities. Thiel stated that "the big, macroeconomic idea that we had at Clarium—the idée fixe—was the peak-oil theory, which was basically that the world was running out of oil, and that there were no easy alternatives." In 2003, Thiel successfully bet that the United States dollar would weaken. In 2004, Thiel spoke of the dot-com bubble having migrated, in effect, into a growing bubble in the financial sector, and specified General Electric and Walmart as vulnerable. In 2005, Clarium saw a 57.1% return as Thiel predicted that the dollar would rally. However, Clarium faltered in 2006 with a 7.8% loss. Thereafter, the firm sought to profit in the long-term from its petrodollar analysis, which foresaw the impending decline in oil supplies. Clarium's assets under management grew after achieving a 40.3% return in 2007 to more than $7 billion by the first quarter of 2008, but fell later in the year and again in 2009 after financial markets collapsed. By 2011, after missing out on the economic rebound, many key investors pulled out, reducing the value of Clarium's assets to $350 million, two thirds of which was Thiel's money. In May 2003, Thiel incorporated Palantir Technologies, a big data analysis company named after the Tolkien artifact. He continues as its chairman, as of 2022. Thiel stated that the idea for the company was based on the realization that "the approaches that PayPal had used to fight fraud could be extended into other contexts, like fighting terrorism". He also stated that, after the September 11 attacks, the debate in the United States was "will we have more security with less privacy or less security with more privacy?". He envisioned Palantir as providing the government the technology to find terrorism without operating illegally. Palantir's reputation is controversial. Although the software only analyzes data collected by the customers, some criticize it for enabling surveillance.[N 3] Professor Vasilis Galis notes that the software is not a mere tool, but shapes policing culture with new policing norms.[N 4] According to Geoff Shullenberger (managing director of Compact) and Moira Weigel (Assistant Professor of Comparative Literature, Harvard), Peter Thiel and Alex Karp built Palantir on the basis of their understanding of Leo Strauss and the Frankfurt School. After the first meeting with Zuckerberg in August 2004, Thiel made a $500,000 angel investment in the startup (then "a three-person dormroom") for a 10.2% stake in the company and joined Facebook's board. This was the first outside investment in Facebook and valued the company at $4.9 million. He also bought Zuckerberg a car. The investment was originally in the form of a convertible note, to be converted to equity if Facebook reached 1.5 million users by the end of 2004. Although Facebook narrowly missed the target, Thiel allowed the loan to be converted to equity anyway. Thiel said of his investment: "I was comfortable with them pursuing their original vision. And it was a very reasonable valuation. I thought it was going to be a pretty safe investment." Facebook employees reported that Thiel's influence was unusual for a board member who was not also the CEO. Some criticized Thiel for pushing his mentee Zuckerberg and the company to the right. Zuckerberg credited Thiel with helping him time Facebook's 2007 Series D, which closed before the 2008 financial crisis. Facebook's initial public offering was in May 2012, with a market cap of nearly $100 billion ($38 a share), at which time Thiel sold 16.8 million shares for $638 million. In August 2012, immediately upon the conclusion of the early investor lock-up period, Thiel sold almost all of his remaining stake for between $19.27 and $20.69 per share, or $395.8 million, for a total of more than $1 billion. In 2016, he sold a little under 1 million of his shares for around $100 million. In November 2017, he sold another 160,805 shares for $29 million, putting his holdings in Facebook at 59,913 Class A shares. As of April 2020, he owned less than 10,000 shares in Facebook. On 7 February 2022, Thiel announced he would not stand for re-election to the board of Facebook owner Meta at the 2022 annual stockholders' meeting and would leave after 17 years in order to support pro–Donald Trump candidates in the 2022 United States elections. In 2005, Thiel created Founders Fund, a San Francisco-based venture capital fund. Other partners in the fund include Sean Parker, Ken Howery, and Luke Nosek. The fund focuses on defense-related startups and technology. After Facebook, even though it was a big financial success, Thiel made the Founders Fund pivot to hard tech, with the reasoning that while companies like Twitter might have a high value, they would not take "civilization to the next level." The Economist notes that the fund and Thiel, personally, have a history of incubating startups that do hypersensitive work related to national security. The fund casts Palantir, Anduril and the newly minted nuclear startup General Matter as the three parts of a trilogy, to which it hopes to add others, among which a plan for onshoring ultraviolet light lithography. Business Insider reports that, among Thiel's inner circle (who know well the billionaire's fondness for Tolkien's works), the fund is nicknamed "the Precious", in reference to the One Ring of Sauron. In addition to Facebook, the Founders Fund made early-stage investments in numerous startups, including Airbnb, Slide.com, LinkedIn, Friendster, RapLeaf, Geni.com, Yammer, Spotify, Practice Fusion, MetaMed, Vator, SpaceX, IronPort, Votizen, Asana, Big Think, CapLinked, Nanotronics Imaging, Powerset (Thiel is on the board of Nanotronics and Powerset), Stripe, Bullish Global (the parent company Block.one had also received investment from Thiel ), AltSchool, Trade Republic, PsiQuantum (photonic quantum computing), and Rigetti Computing (superconducting quantum computing). Thiel also backed DeepMind, a UK start-up that was acquired by Google in early 2014 for £400 million. Founders Fund is an important backer of the Berlin-based platform ResearchGate. Since 2012, Founders Fund had been quietly buying bitcoin, with the investment totaling around $20 million" (Bloomberg remarked that, "the investment amounts to a rounding error for Thiel’s firm."). The company sold the majority of its crypto holdings for $1.8 billion in March 2022 (with bitcoin making up two-thirds of its holdings), right before the market crashed. Also in 2017, Thiel was one of the first outside investors in Clearview AI, a facial recognition technology startup that has raised concerns in the tech world and media for its risks of weaponization. In 2024, alongside General Catalyst and Red Cell Partners, the Founders Fund incubated the defense incubator Valinor Enterprises. The co-founders are former Palantir's senior vice president Julie Bush (CEO), Trae Stephens, General Catalyst's Paul Kwan and Red Cell's Grant Verstandig. In 2024, the Founders Fund led a massive US$85 million seed round for the UAE's decentralized, open-source AI platform SentientAGI (Sentient Foundation), which seeks to challenge Perplexity and OpenAI's closed models as well as handle the problem of AI proliferation, which concentrates power in the hands of large players like Google and Amazon. In 2024 it also invested in Impulse Space (in-space transportation services), Ramp, Crusoe (AI infrastructure using clean energy). In 2025, the Founders Fund invests in Erebor (a new digital bank which is founded by Palmer Luckey and has quickly reached a US$2 billion valuation), EnduroSat (Bulgarian startup that produces Gen3 satellites at scale), Varda (space medicine and hypersonic testbed startup, founded by the Thiel Fellow Delian Asparouhov, Trae Stephens and Will Bruey, and incubated at the Founders Fund), Hadrian Automation. Anduril is a defense hardware startup that was founded in 2017 by Palmer Luckey (who is Thiel's mentee), Joe Chen, Trae Stephens, Matt Grimm and Brian Schimpf (the latter three are Palantir and Founders Fund alumni). The Founders Fund backed the company since its inception, leading its 2017 seed round. The $1 billion (part of the $2.5 billion Series G funding round) the Founders Fund invested in Anduril in June 2025 was the largest investment in the fund's history. In December 2024, it was reported that Palantir and Anduril were forming a consortium of new generation defense companies (which included SpaceX, OpenAI, Scale AI, Saronic Technologies and others) that they would lead in order to challenge the dominance of traditional defense companies. In July 2025, when the Trump administration's budget bill included a provision that required border surveillance towers to be "tested and accepted by U.S. Customs and Border Protection to deliver autonomous capabilities", Edith Olmsted of The New Republic made the criticism that the government favoured Peter Thiel's business, as the provision (which only Anduril fulfilled) effectively ruled out Anduril's rivals, namely General Dynamics and the Israeli-based Elbit Systems. General Matter emerged from stealth in April 2025, focusing on "production and handling of High-Assay, Low-Enriched Uranium (HALEU)." Scott Nolan, who formerly worked for SpaceX, left the Founders Fund to focus on the company and become the CEO, Thiel is also on the company's board of directors, which is noted by the Economist to be a rare occurrence these days. The plant in Paducah, built by General Matter, will be the "first privately developed US uranium enrichment facility". Valar Ventures is an internationally focused venture firm Thiel cofounded with Andrew McCormack and James Fitzgerald in 2010. Valar's portfolio includes TransferWise (now Wise), reforestation-funding finance platform Treecard, fintech startup Atoa (Wise, Treecard and Atoa are based in London), Miami-headquartered Novo and Fortú (digital bank which focuses on underbanked Latino and Hispanic communities), fintech unicorn Qonto, fintech startup Hero, accounting automation software startup Regate (all three are Paris-based), Vienna-based crypto unicorn Bitpanda, Lagos- and London-based banking startup Kuda Bank, Indonesian fintech startup Bukuwarung, Nigerian banking platform Maplerad, Mexican banking startup Albo, banking unicorn N26, B2B paytech Mondu, spend management platform Moss, tax filling unicorn Taxfix, instant payment API startup Ivy (N26, Mondu, Moss, Taxfix and Ivy are all Berlin-based; Ivy is founded by the Thiel Fellow Ferdinand Dabitz), Dubai-based fintech startup Baraka. Valar also invested in New-Zealand based companies including in the software firm Xero, undersea communication company Pacific Fibre and e-reader platform Booktrack. Recent investments include Arkansas-based Panacea Financial (digital fintech for medical practitioners), Riyadh-based SILQ ("largest B2B commerce platform across the Gulf and South Asia", resulted from the recent merger between Bangladesh-based Shop-Up and Saudi-based Sary), Canadian startup Neo (fintech), London-based fertility care startup Gaia. Thiel Capital is a venture capital fund founded by Thiel in 2011 and based in Los Angeles, also referred to as Thiel's family office. It provides "strategic and operational support" for many of Peter Thiel's initiatives and ventures. It incubated and launched Founders Fund, Mithril, Valar, the Thiel Fellowship and Breakout Labs, and also sponsors Crescendo Equity Partners. The firm's investments include Alloy Therapeutics (with Founders Fund and 8VC), EnClear Therapies (Jason Camm became a board member in 2020), the German unicorn ATAI Life Sciences (found by Thiel's friend, the biotech billionaire Christian Angermayer; Jason Camm also became a director in 2020), Compass Pathways (also partly owned by ATAI), Pilgrim (dual-use biotech startup founded by Thiel Fellow Jake Adler), Hugoboom, Rhea, Bullish Global (Founders Fund and Angermeyer are also investors), FTX (also received investment from Rivendell LLC), QA Wolf, Rollup (software platform to develop complex hardware), Neros (military drone startup found by Thiel Fellow Soren Monroe-Anderson), Regent Craft (electric seaglider, invested together with Founders Fund). Thiel Capital is also an investor (including post-IPO financial investment as major backer) of the dual-use German laser communications startup Mynaric. Angermayer also backs Mynaric. Hugoboom's app 28 requires users to input the first day of their last period to calculate the menstrual phases. The app's pro-life rhetoric and scientific basis is controversial. Some of the firm's notable (past) employees include former Austrian chancellor Sebastian Kurz, American politician and entrepreneur Blake Masters, Kevin Harrington (Senior Director for Strategic Planning at the United States National Security Council) and Michael Kratsios. Thiel Capital's investment in the Gilching-based drone startup Quantum-Systems as well as Thiel's subsequent backing of the Berlin-based attack drone startup Stark are sometimes considered controversial, due to Thiel's politics. In May 2025, Quantum-Systems became Europe's first dual-use unicorn and third defense unicorn, after fellow Bavarian startup Helsing and the Portuguese Tekever (Thiel has a role in the success of Helsing too and the startup is considered a part of the "Thiel ecosystem", although he does not directly invest in it). Thiel's mentee Moritz Döpfner brokered the deal with Quantum-Systems on Thiel's behalf and sits on its board. His venture fund Doepfner Capital also invests in Stark. In June 2012, he launched Mithril Capital Management, named after the fictitious metal in The Lord of the Rings, with Jim O'Neill and Ajay Royan. Unlike Clarium Capital, Mithril Capital, a fund with $402 million at the time of launch, targets companies that are beyond the startup stage and ready to scale up. Thiel holds shares in the space-based intelligence company BlackSky through Mithril. It also invests in Helion Energy. The 1517 Fund was founded in 2015 by Danielle Strachman and Michael Gibson, who were both in the founding team of the Thiel Fellowship. The fund provides cash grants and investments, aiming at extending the support already granted by the Thiel Fellowship. It targets "dropouts, renegade students, and deep tech scientists". Peter Thiel backs the fund. Its portfolio companies include Luminar Technologies, Loom, Inc., Atom Computing and Durin Mining Technologies among others. Thiel is the co-founder of America's Frontier Fund, together with Eric Schmidt. The New York Times writes that, America's Frontier Fund is an organization committed to bring manufacturing back to the US, especially that of semiconductors, and the leaders are determined to carry out this mission whether the state helps them or not. InfluenceWatch notes the fund's bipartisan character, with the participation of Ashton B. Carter and H.R. McMaster and the fact that the two founders are left and right-of-center respectively. The chief executive is Gilman Louie. In December 2024, it got approval to get funding from the Small Business Investment Company Critical Technology Initiative (SBICCT), which is "a joint effort by the U.S. Small Business Administration and the Department of Defense." In July 2025, it reportedly raised US$315 million for its first fund. It backs Venus Aerospace, a company develops hypersonic flight using rotating detonation rocket engine (since November 2024) and Foundation Alloy. The fund is characterized by Intelligence Online as "China-sceptic". Around the early 2020s, the Bavarian startup Kleo-Connect successfully developed a highly advanced satellite technology, which is considered much more suitable for governmental and military use than that of Starlink, which was originally conceived for civilian use only. It was feared the technology would fall into the hand of the PLA through its Chinese investors (who invested in the startup since 2018) though. Thus, the German government banned the sale of the company to China, but 144 lawsuits worldwide deterred investors from helping the company to expand the constellation. The founders decided to bring in the US's "highest conservative circles" (which led to the formation of Rivada Space Networks, which drew its personnel mainly from Kleo-Connect, in 2022), among which Karl Rove participated as an investor and lobbyist, and former US secretary of state Mike Pompeo joined the board of the mother company in the US, alongside others like Richard Myers, Jeb Bush, James Loy, Lord Guthrie and the Democrat Martin O'Malley. Rivada Networks's chairman Declan Ganley notes in particular the power of Thiel's name (whose investment in the firm remains undisclosed) in negotiation with investors. The United States Department of Defense is also an investor. Newt Gingrich is noted to have lobbied for the firm too. By 2025, the "politically connected company" has already expanded to 33 countries and collected 16 billion dollars in investments, despite having not launched its satellites (deployment is set to begin in 2027 with initial tests set for 2026). Thiel reportedly works to help the company's development, especially regarding its legal battles. Thiel is an investor and strategic partner of the Oslo-based SNÖ Ventures, having joined the firm in 2021, accompanied by a group of international strategic advisors. In 2024, the fund made its first investment in the defense tech sector, an early funding for the Swedish startup Nordic Air Defence, which developed counter-drone missile technology and is staffed with former employees from Palantir and Quantum Systems. Arctic Today sees this as an evidence of Sweden's strong transatlantic bond which is "seeping into defence", which is also shown in Daniel Ek's Prima Materia's investment in Helsing (which is a strategic partner of Palantir), which happened three months before Russia's 2022 invasion of Ukraine. In 2020, Thiel became a strategic partner and anchor investor of Elevat3, which is set up by Christian Angermayer's Apeiron Investment Group to invest in startups in German-speaking countries. The fund focuses on "life sciences, deep tech, fintech (financial technology), property and insurance". The fund has a partnership with the Founder Fund. In 2020, Thiel invested into the Neunkirchen-based startup Neodigital through the fund. The fund also backs other European startups such as the London-based aggregator startup Olsam. In 2022, through Elevat3 and in partnership with the Founders Fund, the Apeiron Group bought shares from the Chinese Fosun International and others to become a shareholder in the Hamburg-based NAGA Group. Thiel also holds shares in Heidelberger Beteiligungsholding [de] (which will be renamed as SQD.AI Strategies AG), the first dedicated German crypto holding treasury, through the firm. Seoul-based Crescendo Equity is a private equity firm which focuses on mid-cap manufacturing and technology companies in Asia. According to the official website, "Crescendo was established in 2012 with the sponsorship of Peter Thiel". The fund is co-founded by Peter Thiel, Matt Danzeisen (who serves as a member of its investment committee and representative to selected portfolio companies), Andy Lee (company chairman), Matt Price (CEO) and Slava Zhakov (CTO). The president is Anand Chandrasekaran. General Catalyst is also heavily involved in its financing and organization. The fund invests in Line Next (a unit of the Line Corporation), a joint venture between Softbank and Naver. The Business Korea credits Crescendo Equity Partners with transforming Korea's HPSP, which it invested in since 2017, into a global player in the semiconductor equipment sector. In 2025, Crescendo initiated the sale of its 40.9% controlling equity stake in the semiconductor firm, often dubbed Korea's ASML. The three major global PEF firms, Kohlberg Kravis Roberts (KKR), Carlyle, and Blackstone, which are dubbed the "big three buyout funds", have submitted their bids. The firm also plays an important role in the Korean semiconductor industry through investments and support of other companies like Hanmi Semiconductor [ko], Samyang NCchem [ko]. and Movensys (originally known as Soft Servo Group or Soft Motions & Robotics; the name was changed to Movensys in 2021 after Crescendo's investment). The firm also invests in companies that make metal equipment, including Seojin System and Model Solution. Thiel began to explore investing in charter cities on land after his interest in seasteading faded. Thiel is the anchor backer of Pronomos Capital, a firm "set up like a venture capital fund" that seeks to establish experimental, semi-autonomous cities in vacant lands, with acceptance from the countries involved. The founder of the firm is Patri Friedman. Projects backed by the firm include Próspera in Honduras. The Próspera project attracted companies like Oklo Inc. (nuclear startup backed by Thiel's Mithril and Sam Altman) and biotech startups, but led to legal struggles when the new Honduran government changed the laws in 2022. Praxis is a company that seeks to establish a new city-state and has explored Greenland as a possible location. In 2025, when the Danish government was integrating Palantir into the country's military, police and intelligence services, a major argument put forth by opponents was that the Praxis project (backed by Thiel through Pronomos) was a threat to Greenland. Other arguments were concerned with Thiel's politics in the US and Palantir's association with American and other European intelligence services, as well as the security risk that might arise from handing citizens' data to Palantir. The Danish National Police answered with a reference to a 2021 response to the Folketing, but otherwise, the Police, the Danish Security and Intelligence Service and Minister of Justice Peter Hummelgaard refused to comment on the matter. The firm was found in 2023 by Jason Camm (Chief Medical Officer of Thiel Capital). The regulatory filing does not disclose the name of the single investor who provides US$100 million or Thiel's involvement beyond the use of his name. The fund has invested in Ataraxis AI and EnClear Therapies together with the Founders Fund. Reports about investments in October 2025 (infection therapeutics company Peptilogics and cancer treatment startup HistoSonics) confirm that the firm is Thiel's. Hannes Holste from Thiel Capital is a partner. Thiel owns multiple entities named Rivendell, such as Rivendell One LLC, Rivendell 7 and Rivendell 25. Rivendell 7 and Rivendell 25 are personal investment vehicles, which are also used to hold Palantir shares. ProPublica reports that Thiel’s $1,700 PayPal investment and later investments In Palantir and Facebook through a Roth IRA had grown tax-free to over $5 billion by 2019. The Roth was held in Rivendell Trust since 2018. Thiel bankrolled the satellite imaging startup HySpecIQ, known for serving government agencies but struggling financially, through Rivendell Fund. Rivendell entities are known to participate in his German or Korean investments. According to a 2020 article from Bloomberg, Thiel was at the time an investor in funds managed by 8VC and in the bank Disruptive Technology Advisers. A 2017 Globe and mail article names Thiel as a limited partner at Social Capital. He also sponsored Sam Altman's first venture fund, Hydrazine Capital as well as J.D.Vance's Narya Capital. He also backs Doepfner Capital, the venture fund of Moritz Döpfner, the son of Mathias Döpfner. He funded 90% of Zeev Ventures's first fund and has backed it ever since. The Founders Fund was also a backer of the second fund of the Indonesia-focused Intudo. The involvement helped Intudo to validate its mission. Founders Fund is also among the backers of the Israel-based Mensch Capital. Thiel also backs the Singaporean venture investment firm Syfe Group through Valar. The Founders Fund also invested in the Seattle-based private equity fund Privateer Holdings in 2015, thereby becoming the first institutional investor in the cannabis industry. His first investment in a hedge fund managed by an outside manager was made in 2011: the firm was Grandmaster Capital Management, founded by Patrick Wolff, former Clarium and Thiel Macro executive. Also in 2011, he backed the second fund of Joshua Kushner's Thrive Capital. In 2019, Thiel, together with Mark Cuban and Marc Andreessen, backed the San Francisco-based crypto investment fund 1Confirmation. Thiel gives backing to Vivek Ramaswamy's financial firm Strive Asset Management, also described as an activist fund. The firm aims to free "corporate America" of what they deem to be "stakeholder capitalism" ESG mandates created by the three companies BlackRock, Vanguard and State Street and accuse them of causing the energy crisis. The firm does not deny climate science. In 2021, Thiel backed the first fund of A-Star Partners, founded by Kevin Hartz, former partner at Founders Fund. In 2022, he backed B2B-focused Wischoff Ventures founded by solo GP Nichole Wischoff. Thiel is also a major backer of the venture debt firm Tacora, founded by Keri Findley. Its inaugural fund in 2022 raised US$350 million in total, including US$250 million from Thiel. Bloomberg comments that, "It's an unusually large investment for Thiel, the size of which hasn't been previously reported." Findley was originally an associate of Danzeisen, whom she met because she and Thiel Capital both invested in SoFi. Thiel agreed to fund her after she discussed the idea with him at a casual dinner. Alexandra Ulmer and Joseph Tanfani from Reuters remark that Thiel was an instrumental force behind the creation of 1789 Capital, which was co-founded in 2022 by Omeed Malik and Chris Buskirk, a confidant of Thiel's. Blake Masters is also a board member. The fund is intended to create a "parallel economy", a network that combines "businesses, media outlets and political organizations" associated with the America First movement. In 2024, it recruited Donald Trump Jr. as a partner. He personally invests in Quora (leading its Series B), Reddit, and nuclear startup Seaborg Technologies (now Saltfoss Energy). He served on AbCellera's board from 2020 to 2024, when he resigned for personal reasons. Both sides stated that there was no disagreement, with Thiel saying that he was proud to have helped the company and AbCellera's founder Carl Hansen thanking him for his mentorship. He also retains his stake in the company, as of November 2024. In March 2015, Thiel joined Y Combinator as one of 10 part-time partners. In November 2017, it was reported that Y Combinator had severed its ties with Thiel. In 2024, Thiel became the lead funder of the Enhanced Games, a proposed multi-sport event that will allow athletes to use performance-enhancing substances without being subject to drug tests. The founder is the Australian lawyer Aron D'Souza, who came to know and become Thiel's confidant in the process of leading the Gawker case for him. Angermayer, who was introduced to D'Souza by Thiel, also invested, even though, as per Wired, Thiel and Angermayer were not normally interested in sports. The startup agrees to cover legal expenses for any clean athletes who participate in the event and are banned from mainstream competitions as a result. In 2018, the Founders Fund invested in the Israeli company Carbyne (emergency service). Leaked emails (released by the hacker group Handala, which "likely operates out of Iran's Ministry of Intelligence", according to Reuters) show that in 2014, Jeffrey Epstein leveraged his relationship with former Israeli Prime Minister Ehud Barak to get access to Thiel. Epstein arranged for Barak to meet Thiel in New York on June 9, 2014. In 2016, Epstein pitched Reporty (later Carbyne) to Valar, but the proposal got rejected on account of being premature (Epstein invested in total 40 million in Valar in 2015 and 2016).). Valar's McCormack said they would try to reengage when the startup was more developed. In 2018, the Founders Fund joined Carbyne's $15 million Series B. Thiel said that the subsequent interactions with Epstein following their introduction in 2014 were due to the fact Epstein was a "crazed networker". One of the people introduced to Thiel by Epstein was the Russian diplomat Vitaly Churkin. Byline Times suggests that Epstein was one of contact points that Thiel used for his political network in the UK, including with on the Labour Party (UK), although there is no record of Thiel's social visits to Epstein's homes or flights on his jet. Documents reviewed by The Wall Street Journal in 2023 show that there were scheduled meetings (half a dozen between 2014 and 2016) between Thiel and Epstein, including with others such as Woody Allen and Obama's advisor Kathryn Ruemmler. Reid Hoffman, Thiel's friend from the PayPal Mafia and a big Democratic donor was the one who directly introduced Thiel to Epstein (for years Epstein acquaintances had tried to invite Thiel to meet Epstein but were rejected) and also participated. Documents from the US House of Representatives showed Epstein invited Thiel to his private island in 2018. A spokesperson for Thiel said he never visited the island. In 2025, Snopes criticized a claim on the internet that Epstein offered girls to Thiel and others as misleading by omitting context. Journalist Whitney Webb claims Palantir is a CIA front, and links Thiel to the CIA, Mossad, and Epstein's alleged plan for an "Orwellian nightmare." Webb has shared these theories via the Chinese website of MintPress News – known for being part of the "Russian web of disinformation" – and Trineday, a publisher founded by conspiracy theorist Kris Millegan. The Washington Report on Middle East Affairs lists her as a MintPress journalist. Euronews writes that there is no known major financial connection between Thiel and Epstein, but Thiel seemed to treat Epstein as a contact point. The San Francisco Standard comments that around the time, other Israeli officials (acting independently of Barak) tried to build contact with Thiel as well, often aiming at a "lucrative" job at Palantir. Gawker lawsuit In May 2016, Thiel confirmed in an interview with The New York Times that he had paid $10 million in legal expenses to finance several lawsuits brought by others, including a lawsuit by Terry Bollea (Hulk Hogan) against Gawker Media for invasion of privacy, intentional infliction of emotional distress, and infringement of personality rights after Gawker made sections of a sex tape involving Bollea public. The jury awarded Bollea $140 million, and Gawker announced it was permanently closing due to the lawsuit in August 2016. Thiel referred to his financial support of Bollea's case as one of the "greater philanthropic things that I've done." Thiel said he was motivated to sue Gawker after they published a 2007 article publicly outing him, headlined "Peter Thiel is totally gay, people." Thiel stated that Gawker articles about others, including his friends, had "ruined people's lives for no reason," and said, "It's less about revenge and more about specific deterrence." In response to criticism that his funding of lawsuits against Gawker could restrict the freedom of the press, Thiel cited his donations to the Committee to Protect Journalists and stated, "I refuse to believe that journalism means massive privacy violations. I think much more highly of journalists than that. It's precisely because I respect journalists that I do not believe they are endangered by fighting back against Gawker." Owen Thomas, the author of the Gawker article, stated that he did not think it was an outing in the conventional sense, as Thiel had been open about his homosexuality, but the "strangely conservative" Silicon Valley had refused to talk about it. Thiel said that the problem was less about the outing itself, but the troubles it caused with regard to his business in Saudi Arabia and his parents. On 15 August 2016, Thiel published an opinion piece in The New York Times in which he argued that his defense of online privacy went beyond Gawker. He highlighted his support for the Intimate Privacy Protection Act and said that athletes and business executives have the right to stay in the closet as long as they want to. In an open letter to Thiel after losing the case, Gawker's Nick Denton accused Thiel of making them "stripped naked", together with the warning "in the next phase, you too will be subject to a dose of transparency. However philanthropic your intention, and careful the planning, the details of your involvement will be gruesome." Later though, in 2025, Denton said that Thiel was right and did him a favor in forcing the sale of Gawker Media. Views and political activities Thiel is described by different authors and media sources in different ways. He identifies as a libertarian. He has been called an Ayn Rand libertarian, plutocratic reactionary, militarist techno-libertarian, and libertarian authoritarian. His attitude towards democracy has been described as democracy-skeptic, partly antidemocratic, or post-democratic. French economist Yann Algan links Peter Thiel and Elon Musk to the concept of "liquid democracy" and the rise of libertarian AI governance, which Algan defines as "a radically decentralized, algorithm-driven democracy", which "prioritizes efficiency and individual freedom over democratic safeguards". Thiel's biographer Max Chafkin notes that his thinking is a mix of libertarianism and authoritarianism, but describes what Thiel truly believes and wants as a mystery. Thiel describes himself as a political atheist. He opines that trying to radically alter the current U.S. government is unrealistic. He also suggests that Curtis Yarvin methods will lead to Xi's China or Putin's Russia. He does not deny the value of statemanship though,[N 5] but opines that "people should spend less time trying to change the system than simply creating things outside it". Journalist Murad Ahmed from Financial Times calls Thiel "philosopher king at the very top of Silicon Valley" (with France 24 using a similar description). German philosopher Peter Sloterdijk also remarks: "Peter Thiel can be seen as more of a philosopher king. He acts very coolly and strategically – a dazzling figure, far outside our left-liberal perception patterns", while Ross Douthat from New York Times describes him as "most influential right-wing intellectual of the last 20 years". Commenting on Douthat's description, Luke Munn of the University of Queensland notes that, "Thiel's influence on politics is at once financial, technical and ideological [...] his potent cocktail of networks, money, strategy and support exerts a rightward force on the political landscape." In 2025, the author Ijoma Mangold [de] wrote an article for Die Zeit, describing Thiel's theories as obscure and incoherent at first glance, but often displaying an accurate intuition, while noting that both the man and his ideas "simultaneously fascinates, repels, and outrages." Later the author René Martens wrote on Mitteldeutscher Rundfunk, criticizing Mangold and Die Zeit for masking their admiration with pseudo-criticism and called Thiel a disciple of Carl Schmitt. In 2009, The Guardian stated that Thiel was a member of the neoconservative, Reaganite/Thatcherite "TheVanguard.org". The outlet said Thiel believes the Enlightenment led humanity from nature's rule to a world where nature has been conquered, and also noted Thiel's philosophy disregarded art, beauty, love, pleasure, and truth. The Guardian linked Thiel's investment in projects like the Singularity Institute to his belief in life-extension technologies as an escape from humanity's "nasty, brutish, and short" life. It criticized him for seeking to replace the natural world with a virtual one. Vadym Kovalenko notes that during the 90s and 2000s, Silicon Valley followed the spirit of Steve Jobs, who saw technology as art. But later this has translated into Thielism, which emphasizes "truth, the ideal, ontology" and matters like flying to Mars, curing aging and creating a new world over the superficiality. Kovalenko sees Thiel as a humanitarian Über-artist. On the question of exotericism versus esoteticism, Paul Leslie writes that in "The Straussian moment", Thiel tries to "weave together Schmitt's political theology—with its emphasis on the friend/enemy distinction—and Strauss's advocacy for esoteric wisdom and hidden hierarchies." In the article "Exotericism and the Untroubled Race for the Future", Thiel discerns between ancient esotericism, in which "thrice-great Hermes revealed his magical recipes only to a few" and "modern esotericism of grantwriting". He remarks, though, that exotericism takes time, and Goethe was "perhaps [...] the last human being to command the sum total of human knowledge." Writing for the Quarterly Journal of Speech in 2024, James Rushing Daniel wrote that: (...) "a rhetor ambitiously capitalizing on the material crises and political disillusionment of the day, defending a "cultural revolution" to put an end not just to the progressivism of the long 1990s but the values of collectivism and social justice and the remnants of social democracy and the Keynesian welfare state, replacing them with Randian individualism and the absolute dominance of the capitalist project." According to Daniel, Thiel has financially supported the intellectual wing of "the reactionary, traditionalist turn of conservative politics" termed by some as "the New Right". The Nation notes that he advocates "for a dramatic, right-wing political turn to address technological stagnation". Nick Land attributed Thiel's 2009 essay "The Education of a Libertarian" and statement that "I no longer believe that freedom and democracy are compatible" as a watershed moment in the development of the Dark Enlightenment movement. Patrick Zarrelli argues the quote is misread as anti-democratic, when Thiel's real concern is that mass democracy could erode the freedoms essential for innovation, but notes that Thiel underestimates the limits of technocracy like lack of democratic accountability. Zarelli remarks that Thiel has partially realized his philosophy: "By aligning technology with national priorities like defense modernization, pandemic response, and intelligence fusion. He has built parallel governance inside the state itself.", and notes that critics call Thiel a "shadow oligarch". Zarelli opines that a solution might be a hybrid form between technocracy and democracy. Italian professor Giuliano da Empoli opines that Thiel represents the alliance between the post-modern Silicon Valley and the archaic Trump, that threatens democracy. The author recognizes that the Silicon Valley actors are gifted and have the means to govern more efficiently than democratic institutions in some respects. He argues that humanity must not respond to post-modern tech leaders like the Aztecs did to the conquistadors, but must instead make deliberate choices about which areas should still prioritize democratic decision-making, even at the risk of less efficient outcomes. In his book L'Empire de l'ombre, Da Empoli echoes the sentiment of Thiel's quote, "Darker questions still emerge in these dusky final weeks of our interregnum," interpreting the "apocalypse" not as the end of the world, but as a sudden unveiling of forces that had long been taking shape beneath the surface. Blue Labour founder Maurice Glasman (who first met Thiel at Oxford, where Glasman rebuked Thiel's description of the British Empire as the Antichrist) denounces Thiel's view on democracy but defends leftist politicians' interaction with Thiel, saying that parties which have no place in the AI conversation will be out of the game very fast. Danish politician Christopher Arzrouni [da] dismisses Dagbladet Information's description of Thiel as a Prussian warhorse (preussisk kamphest) or a bigot tech prince who would bring the end of democracy or the world, calling him "a smart European who finds better opportunities in the U.S.", and criticizes European intellectuals' fear of new technology. Jacob Silverman noted that Thiel's actual political work drifted away from libertarianism, but it remained his intellectual guiding star. Jack Nicastro of Reason notes that Thiel's solution for "the dangers of government overreach and a one-world state" is "surprisingly libertarian". George A. Dunn believes that Thiel is the pathbreaker in connecting the thoughts of Girard and Strauss to debates on the origins of modernity. Thiel is a self-described conservative libertarian. Since the late 2010s, he has espoused support for national conservatism, and criticized economically liberal attitudes towards free trade and Big Tech. Thiel advocates that companies should avoid competition and attention, and try to develop into monopolies by creating something new, dominate a niche market before expanding into slightly broader markets. He notes that years or even decades of profits can come from such specific markets. In The Straussian Moment, Thiel notes that, "Since 1920, the vast increase in welfare beneficiaries and the extension of the franchise to women – two constituencies that are notoriously tough for libertarians – have rendered the notion of 'capitalist democracy' into an oxymoron." After the statement caused controversies, he replied that, he had made a "commonplace statistical observation about voting patterns that is often called the gender gap", and that women's right to vote was not under siege nor would taking it away solve any problem, but people should focus on projects outside of voting and politics. Adam Rogers contends that this essay has prefigured the Department of Government Efficiency project. In the 2025 Douthat interview, Thiel stated that, "Reagan was consumer capitalism, which is oxymoronic. You don't save money as a capitalist; you borrow money. And Obama was low-tax socialism – just as oxymoronic as the consumerist capitalism of Reagan." In 2021, Thiel wrote an article for Die Welt, claiming that the extreme political experiments of fascism and communism in the 20th century had led Germany to fear extremism in both politics and technology. However, as "the decisive arena for the future of the West", being the land of poets and thinkers would not be enough for Germany in the new era. He criticized "green quietism" and opined that new ideas could be dangerous but would be the source of growth. In a 2015 conversation with Tyler Cowen, Thiel claimed that innovative breakthroughs were happening in computing/IT and not the physical world. He lamented the lack of progress in space travel, high-speed transit, and medical devices. As a cause for the discrepancy, he said: "I would say that we lived in a world in which bits were unregulated and atoms were regulated." The Founders Fund and Khosla Ventures are backers of the Hill & Valley Forum, a group that is described by the Wall Street Journal as an anti-China alliance between Silicon Valley and Capitol Hill. In an article named Silicon soldiers of fortune, the China Daily, the channel of the Central Propaganda Department of the Chinese Communist Party, identifies Thiel, Palmer Luckey and Jacob Helberg as tech hawks who are increasingly shaping the US policy towards China. The Xinhua News Agency, China's official state news agency, states that Palantir and its leaders like Thiel and Vice President Wendy R. Anderson as well as other companies like Anduril and Saronic Technologies, as representatives of "the new military industrial complex", are an unpredictable danger to the US and the international community. The tech-focused outlet 36Kr though praises his long-term vision and methods in breaking down the traditional barriers in the US military-industrial complex and government sector, and his contribution to leading startups like Palantir, Anduril and SpaceX. The Brazilian newspaper Brasil de Fato (described by The New York Times as part of a "global web of Chinese propaganda") portrays Thiel as "the brightest anti-communist in the US", part of the anti-China brigade, "the leader of the tech-based section of the military-industrial complex" as well as "the most geo-politically strategic tech billionaire" and "the most dangerous non-state figure in the world today". According to Brasil de Fato, among all the capitalists, Thiel has the strongest grip on the National Security Council. In 2019, Thiel called Google "seemingly treasonous" and urged a government investigation, citing Google's work with China and asking whether DeepMind or Google's senior management had been "infiltrated" by foreign intelligence agencies. In 2025, Thiel called for a drastic reset in economic relations with China, stressing that economic relations should be viewed from a geopolitical standpoint as well. In an discussion with Peter Robinson, he opined that the US should not let itself be stuck between two extreme views about China (that China itself encourages to promote an attitude of political inaction towards them): "It's China is super weak, and China is super strong. And I've been in meetings in China where in some sense you got both messages within 20 minutes of one another, and it's like logically inconsistent but psychologically it doubles up." In 2024, Palantir became a strategic partner of Israel in military technology in an occasion both Thiel and Karp visited the country. In a 2024 interview with Bari Weiss, Thiel advocated cooperation with Israel to deter Iran from getting nuclear weapons: One of the lessons I take of the mid-20th century was every time a country got a nuclear weapon, we got a regional war. The Soviet Union gets the bomb in 1949. The Korean War starts in 1950 because when the Soviet Union backs North Korea, we can't bomb Russia. Then they can back North Korea with impunity, and we get a massive, massive regional war. That's, in a way, the price for being asleep at the switch and letting the Soviets get the bomb. 1964, Communist China gets the bomb. Vietnam War explodes in 1965. And again, China can back North Vietnam with impunity. We can't reciprocate. And the way I understand why would an Iranian nuclear bomb be a catastrophe? Because the degree to which Iran can support this plethora of bad actors, the Houthis, the Hamas people, and Hezbollah, and on and on throughout the Middle East, you could not retaliate against Iran [...] And so we don't have to go to the crazy theocracy that said they'd use the bomb and would use it. Regarding the Russia-Ukraine war, he opined that "the relentless NATO expansion might not have been a good idea", but the US could not simply retreat from Ukraine, because it would become a rout. In 2025, writing for the Singapore-based think tank ThinkChina, Artyom Lukin, a leading Russian expert on Asia-Pacific geopolitical issues, wrote that Thiel, whom Lukin described as "the éminence grise of Trump's own deep state" and "the most anti-China figure in the US top elite", together with his allies, were pushing the American geostrategy towards focusing on China (a country Thiel saw as "a half fascist, half communist gerontocracy" with "a socialism of a nationalistic sort, and [...] extremely racist.") as the paramount threat. Lukin noted that Thiel had little sympathy for Russia, but viewed it as a lesser threat and did not want to push Moscow towards Beijing's arms. According to The Intercept, Thiel is the source of the warrior culture in Silicon Valley, one focused on an arms race with China, although the anti-China sentiment is found on both sides of the political spectrum. Alex Karp notes that Palantir has a warrior culture, which values excellence over money. Thiel is a member of the Steering Committee of the Bilderberg Group, a gathering of intellectual figures, political leaders, and business executives, characterized as focused on defense and espionage, as well as Atlanticist and Europhile. Thiel's outsized influence at the gathering has been noted. Thiel, together with Auren Hoffman, is also the founder of Dialog, which is often compared to Bilderberg, but focuses more on tech. It does not share the lists of participants but is known to have invited American tech and political leaders, as well as intellectual heavyweights, on both sides of the political spectrum, as well as representatives from Europe and Middle East. Past topics included "AI's energy demands, the future of health care, and political realignments" and "caring for aging parents, love, mental health and the afterlife." Palantir is partner of the World Economic Forum, but Thiel has not gone to the meeting since 2013, because he considers it a place without individuals – there are only representatives of companies, governments and NGOs. He opines that some types of global governance might work, but it is necessary to have dissenting views. The Thiel Foundation is a supporter of the Committee to Protect Journalists (CPJ), which promotes the right of journalists to report the news freely without fear of reprisal. Beginning in 2008, Thiel has donated over $1 million to the CPJ. He is also a supporter of the Human Rights Foundation, which organizes the Oslo Freedom Forum. In 2011 he was a featured speaker at the Oslo Freedom Forum, and the Thiel Foundation was one of the event's main sponsors. He also backs the Alliance of Democracies Foundation founded by Anders Fogh Rasmussen. Thiel has supported mostly conservative gay rights causes such as the American Foundation for Equal Rights and GOProud. He invited conservative columnist and friend Ann Coulter to Homocon 2010 as a guest speaker. Coulter later dedicated her 2011 book, Demonic: How the Liberal Mob Is Endangering America, to Thiel. In 2012, Thiel donated $10,000 to Minnesotans United for All Families, in order to fight Minnesota Amendment 1 that proposed to ban marriage between same-sex couples there. In 2009, it was reported that Thiel helped fund James O'Keefe's "Taxpayers Clearing House" video—a satirical look at the Wall Street bailout. O'Keefe went on to produce the ACORN undercover sting videos; Thiel denied involvement in the ACORN sting. In July 2012, Thiel made a $1 million donation to the Club for Growth, a fiscally conservative 501(c)(4) organization, becoming the group's largest contributor. He is a major backer of the conservative Rockbridge Network, which is now an international network with Asian branches. In 2023, Business Insider reported that Thiel became an FBI informant in 2021. Business Insider also noted the fact that politicians sponsored by Thiel, including Vance and Masters, had repeatedly attacked the FBI and its leadership in public. According to former FBI agent Jonathan Buma, Peter Thiel, Elon Musk and David Sacks have been targets of Russian intelligence. Buma notes that Thiel cooperated with the FBI to identify the foreign espionage network. He visited president of Argentina and fellow libertarian Javier Milei three times in 2024. The Noticias de América Latina y el Caribe (NODAL) remarks that the cooperation between Thiel and Milei marks the political alignment between Argentina and Washington and Silicon Valley, also through organizations like Endeavor. According to NODAL, the introduction of Argentina into Thiel's network is erasing traditional politics while promoting a tech-based order which increases efficiency but also puts sovereignty at stake. Matt Stoller, research director of American Economic Liberties Project, remarks that Thiel is a "really smart nihilist", and notes that his focus is entirely on power. Thiel's biographer Max Chafkin writes that this is a likely explanation for Thiel's activities. In 2017, Thiel reportedly refused the offer to become chairman of the president's intelligence advisory board, despite Trump's urging. In the same year, there were reports that he considered becoming U.S. Ambassador to Germany or a bid for governorship of California. At the time, he said that he was not interested in a full-time job in politics. In 2024, he said that he had gotten used to tech and a full-time job as a politician would lead to depression. Thiel is a member of the Republican Party. He contributes to both Libertarian and Republican candidates and causes. In December 2007, Thiel endorsed Ron Paul for President in the 2008 United States presidential election. After Paul failed to secure the Republican nomination, Thiel contributed to the John McCain campaign. In 2010, Thiel supported Republican Meg Whitman in her unsuccessful bid for the governorship of California. He contributed the maximum allowable $25,900 to the Whitman campaign. In 2012, Thiel, along with Nosek and Scott Banister, put their support behind the Endorse Liberty Super PAC. Collectively they gave $3.9 million to Endorse Liberty, whose purpose was to promote Ron Paul. After Paul again failed to secure the nomination in the 2012 United States presidential election, Thiel contributed to the Mitt Romney/Paul Ryan presidential ticket of 2012. Thiel initially supported Carly Fiorina's campaign during the 2016 GOP presidential primary elections. After Fiorina dropped out, Thiel supported Donald Trump and became one of the California delegates for Trump's nomination. He was a headline speaker during the 2016 Republican National Convention, during which he announced that he was proud to be gay, Republican, and American, for which the assembled Republicans cheered. On 15 October 2016, Thiel announced a $1.25 million donation in support of Donald Trump's 2016 presidential campaign. Thiel stated to The New York Times: "I didn't give him any money for a long time because I didn't think it mattered, and then the campaign asked me to." After Trump's victory, Thiel was named to the executive committee of the president-elect's transition team. In 2017, Gavin Newsom (then lieutenant governor of California), whose campaign and marijuana legalization effort Thiel had supported, noted that Thiel cared deeply about criminal justice reform and had done a lot of behind-the-scene good work on marriage equality, which he was also passionate about. Newsom remarked, though, that "None of us are jumping up and down that he's aligned himself with President Donald Trump." By February 2022, Thiel was one of the largest donors to Republican candidates in the 2022 election campaign. By November 2022 he had spent 32 million. He supported 16 senatorial and congressional candidates. Two of said senatorial candidates (Blake Masters (who lost his race) and later U.S. Vice President JD Vance) were also tech investors who had previously worked for Thiel. In 2023, Barton Gellman of The Atlantic wrote in an article interviewing Thiel that Thiel "has lost interest in democracy" and that "he wouldn't be giving money to any politician, including Donald Trump, in the next presidential campaign". According to Reuters this occurred after he disagreed with the Republican party's focus on cultural issues. In the same Atlantic interview, he stated that the first Trump administration failed even his initial low expectations. In 2024, he described Trump as a clown whom Reid Hoffman's lawsuit turned into a martyr. In 2025, when interviewed by Ross Douthat, Thiel indicated that Trump and the populists were a disruptive factor that would prepare the stage for the process of true rebuilding (in 2023, he also opined that Trump's election would "slash regulations, crush the administrative state – before the country could rebuild"). He stressed that the support of large parts of the Silicon Valley for Trump was not pro-Trump in nature. He stated that disruption did not equal progress, and even his thought of trying to having a conversation with Trump about it (in Trump's first term) later proved "a preposterous fantasy". But he was satisfied about the fact that in the second term, deregulation was happening, for example regarding nuclear energy. Thiel has his own political-action committee, Free Forever, which is committed to supporting political candidates who support stricter border control, restrictive immigration policy, funds for veterans, and anti-interventionist foreign policy, among other things. According to OpenSecrets, the PAC was active only during the 2020 election cycle and then only in support of Kansas attorney general Kris Kobach's failed U.S. Senate bid. The campaign by Kobach, who lost in the Republican primary, had received almost all of its contributions from Thiel himself. In 2025, Brendan Glavin, director of insights for OpenSecrets, remarked that Thiel's political donations have "an ideological agenda that's not strictly motivated by financial or business concerns [...] His views are libertarian generally, and he wants to elect people who are like minded." Philanthropy Thiel carries out most of his philanthropic activities through the Thiel Foundation. In 2006, Thiel provided $100,000 of matching funds to back the Singularity Challenge donation drive of the Singularity Institute for Artificial Intelligence (now known as the Machine Intelligence Research Institute), a nonprofit organization that promotes the development of friendly artificial intelligence. He provided half of the $400,000 matching funds for the 2007 donation drive, and as of 2013 the Thiel Foundation had donated over $1 million to the institute. Additionally, he has spoken at multiple Singularity Summits. At the 2009 Singularity Summit, he said his greatest concern is the technological singularity not arriving soon enough. In December 2015, OpenAI, a nonprofit company aimed at the safe development of artificial general intelligence, announced that Thiel was one of its financial backers. In September 2006, Thiel announced that he would donate $3.5 million to foster anti-aging research through the non-profit Methuselah Mouse Prize foundation. He gave the following reasons for his pledge: "Rapid advances in biological science foretell of a treasure trove of discoveries this century, including dramatically improved health and longevity for all. I'm backing Dr. [Aubrey] de Grey, because I believe that his revolutionary approach to aging research will accelerate this process, allowing many people alive today to enjoy radically longer and healthier lives for themselves and their loved ones." As of February 2017, he had donated over $7 million to the foundation. When asked "What is the biggest achievement that you haven't achieved yet?" by the moderator of a discussion panel at the Venture Alpha West 2014 conference, Thiel said he wants to make progress in anti-aging research. Thiel also said that he is registered to be cryonically preserved, meaning that he would be subject to low-temperature preservation in case of his legal death in hopes that he might be successfully revived by future medical technology, and is signed up with the Alcor Life Extension Foundation. Thiel has expressed interest in the science of parabiosis, including young blood transfusion for potential health benefits. He said in a 2016 Inc. interview that the technology had been found to work on mice before being strangely dropped after the 1950s. The same Inc. article reported that the Thiel Capital medical director Jason Camm had contacted the transfusion startup Ambrosia, but its founder Jesse Karmazin told TechCrunch in a 2017 article that they had never been contacted by Thiel or Thiel Capital. In a 2022 Jacobin article, Ben Burgis characterizes the blood transfusion story as part of a deliberate attempt by Thiel to portray himself as an "evil genius". On 15 April 2008, Thiel pledged $500,000 to the newly created non-profit Seasteading Institute, directed by Patri Friedman, whose mission is "to establish permanent, autonomous ocean communities to enable experimentation and innovation with diverse social, political, and legal systems." At one of the institute's conferences, he described seasteading as "one of the few technological frontiers that has the promise to create a new space for human freedom." In 2011, Thiel gave $1.25 million to the Seasteading Institute, but resigned from its board the same year. In a 2017 interview with The New York Times, Thiel said seasteads are "not quite feasible from an engineering perspective" and "still very far in the future". On 29 September 2010, Thiel created the controversial Thiel Fellowship, which annually offers them a total of $100,000 (raised to $200,000 since 2025) over two years to 20 people under the age of 23 in order to spur them to drop out of college and create their own ventures. According to Thiel, many young people choose college simply because they're unsure of what else to do with their lives. He envisions a future system that offers different paths for different people, and believes that change in the university system will require external pressure ("Reformation") before any internal willingness to adapt can arise. In November 2011, the Thiel Foundation announced the creation of Breakout Labs, a grant-making program intended "to fill the funding gap that exists for innovative research outside the confines of an academic institution, large corporation, or government." It offers grants of up to $350,000 to science-focused start-ups, "with no strings attached". In April 2012, Breakout Labs announced its first set of grantees. In total, 12 startups received funding, for a total of $4.5 million in grants. One of the first ventures to receive funding from Breakout Labs was 3Scan, a tissue imaging platform. Breakout Ventures is a privately held venture capital firm founded in 2016 out of Breakout Labs to invest in science. Based in San Francisco, California, it invests in early-stage companies in technology, biology, and chemistry focused on human health and sustainability. The program focuses on biotech with a mix of hardware. Its partners include Founders Fund, Formation 8, OATV, Lux Capital, Khosla Ventures among others. Some of its recent investments include Noetik (cancer treatment), Phantom Neuro (neurotechnology). Corpernic Catalysts (catalysts for ammonia production), EnPlusOne Biosciences (RNA therapeutics), Passkey Therapeutics (synergistic multifunctional therapeutics), Cytovale (medical diagnostics). In 2011, Thiel made a NZ$1 million donation to an appeal fund for the casualties of the Christchurch earthquake. In Girard's honour, he has established the Imitatio project (part of the philanthropic Thiel Foundation), which aims to "supports research, education, and publications building on Rene Girard's mimetic theory." Personal life Thiel resided in San Francisco, California, until 2018, when he moved to Los Angeles. He had criticized San Francisco for being "intolerant of conservatives, insular and overpriced". Both Thiel Capital and Thiel Foundation followed him to Los Angeles, but the Founders Fund remains in San Francisco. Mithril's headquarters moved to Austin. Thiel married his long-time partner, Matt Danzeisen, in Vienna, Austria, on Thiel's 50th birthday (October 2017), when he was reported to have proposed to Danzeisen. Danzeisen started his career as an investment banker at Bank of America Securities. By 2007, when the couple were dating, Danzeisen was vice president of BlackRock. By 2021, he was chairman of Bridgetown 1 and Bridgetown 2, sponsored by Thiel Capital and Richard Li's Pacific Century Group. Sam Altman also sat on the board. Danzeisen also participates in other Thiel enterprises related to the family of Li Ka-shing (father of Richard Li), such as the Malta-based EUM. In 2017 Danzeisen was working as head of private investments at Thiel Capital, with a primary focus on North America and Asia. Thiel and Danzeisen have two young daughters, aged five and three as of June 2024, born through a surrogate. Adrian Wooldridge from Bloomberg reported in August 2025 that Thiel had four children. In 2023, in an interview with the Atlantic, Thiel noted that Danzeisen had tried to dissuade him from donating money to Republicans. Thiel was in a long-term relationship with model Jeff Thomas until Thomas's suicide in March 2023. Media coverage of Thomas's death drew widespread attention, partly because of Thomas's involvement with Democratic researchers led by David Brock and Jack Bury. Puck.news wrote that the anti-Thiel campaign exposed an undercurrent in modern politics in which there is an increasing tendency towards using people's private problems to achieve political goals. Thiel is a self-described Christian and a promoter of René Girard's Christian anthropology. Girard, a Catholic, explained the role of sacrifice and the scapegoat mechanism in resolving social conflict, which appealed to Thiel as it offered a basis for his Christian faith without the fundamentalism of his parents. Thiel grew up in an evangelical household but, as of 2011, described his religious beliefs as "somewhat heterodox", stating: "I believe Christianity is true but I don't sort of feel a compelling need to convince other people of that." According to Thiel, "Christianity for me is the anti-identity. Your identity is in Christ [...] and it's in that context we can figure out things about the world and truth [...] [Truth] is not a social construct." Thiel has participated in Veritas Forum events with the theologian N. T. Wright discussing religion, politics, and technology. Thiel opines that wokeism or "the woke religion" is a type of secular religion, which is "in some ways [...] anti-Christian and some ways [...] hyper-Christian" and fills the void of a weakened Church because people are attached to post-Christian values rather than a "rationalist, atheist" worldview. He notes that wokeism has a concept of the original sin as well as demands confession and repentance, while offering no transcendental values, no forgiveness or chance of redemption through sacrifice. He claims that this strand of thinking, which attacks Christians for not doing enough for victims or the poor, is a continuation of communism and the social gospel, which also inherit some Christian characteristics while being anti-Christian at the same time. Mikhail Minakov writes that "Thiel's conception of will integrates Christian eschatology, Girardian mimetic theory, and Straussian elitism to critique the impotence of liberal democracy while proposing the efficiency of a techno-feudal alternative." Elke Schwarz, a professor of political theory, notes that Peter Thiel and Marc Andreessen are the foremost proponents of techno-eschatology, which demonstrates the sacralizing of AI and uses spiritualism to bolster the logic of venture capitalism. Thiel opines that, "Crypto is decentralizing, AI is centralizing. Or, if you want to frame it more ideologically, crypto is libertarian and AI is communist." A topic Thiel is interested in is the Antichrist, Armageddon and Apocalypse, about which he has given talks in multiple events, including a September 2025 series of off-the-record private lectures organized by David Wood's Acts 17 Collective in San Francisco, which drew a group of protesters. Thiel opines that different people are worried about different apocalyptic threats like environment degradation, nuclear wars or bioweapons. He recognizes these as credible threats, but sees a total one-world government as closer to the Antichrist. He sees humanity as facing the double threats of the Antichrist and the Armageddon, which is the collapse of civilization through global warfare. He sees salvation in the figure of the Katechon, a mysterious force that restrains the Antichrist. He has referred to individuals, organizations, communism or even anti-tech regulations as precursors of the Antichrist. For example, he referred to environmental activist Greta Thunberg and AI safety advocate Eliezer Yudkowsky as “legionnaires of the Antichrist”. Different commentators see his Antichrist theory as a narrative to highlight the role of a hero, or a framework to attack political opponents or an attempt to brand himself as tech's free thinker (who has also touched on topics such as the Kennedy assassination, Epstein's crimes or aliens). Kayla Carman from the Russian Strategic Culture Foundation writes that the hero Thiel describes is implied to be Thiel himself, and states that Thiel, "auditioning for a role in a cosmic drama that no one asked him to star in", will never be this savior of civilization he aspires to be and the true Katechon should be "our collective refusal to be restrained" by billionaire philosopher kings. German scholar Adrian Daub, Professor of German and Comparative Literature at Stanford University, describes the lectures as "amateurish talks" and a desperate effort from a man with immense power and full of contradiction to disassociate himself from his own power and even his attempts to be understood. Professor Matthew Avery Sutton, representing the Washington State University, notes that Thiel is sincere in his interest in Christianity and draws from serious sources, but suggests that leaders should stop dressing their political theories in apocalyptic dress, because this will "raise anxieties, delegitimize compromise and insinuate that democratic deliberation is spiritually suspect". Others contend that Thiel's arguments make no sense and that his "fixation on apocalyptic scenarios reveals less about looming biblical prophecy than about the anxiety of a tech elite resisting limits on capital and code at a moment when public pressure for accountability is rapidly growing". Thiel began playing chess at the age of six and was at one time one of the top junior players in the United States. He holds the title of Life Master, but he has not competed since 2003. On 30 November 2016, Thiel made the ceremonial first move in the first tiebreak game of the World Chess Championship 2016 between Sergey Karjakin and Magnus Carlsen. He said that he stopped trying to become better at chess, because once a certain level had been reached, chess created an alternate reality that made him lose sight of the real world. Thiel is an occasional commentator on CNBC, having appeared on both Closing Bell with Kelly Evans, and Squawk Box with Becky Quick. He has been interviewed twice by Charlie Rose on PBS. He has also contributed articles to The Wall Street Journal, First Things, Forbes, and Policy Review, a journal formerly published by the Hoover Institution, on whose board he sits. In The Social Network, Thiel was portrayed by Wallace Langham. He described the film as "wrong on many levels". His distaste for the portrayal led to the establishment of the Thiel Fellowship on a whim. Thiel was the inspiration for the Peter Gregory character on HBO's Silicon Valley. Thiel said of Gregory, "I liked him [...] I think eccentric is always better than evil". Jonas Lüscher stated in an interview with Basellandschaftliche Zeitung that he based the character Tobias Erkner in his novel Kraft ("Force") on Thiel. After he hired former Austrian chancellor Sebastian Kurz (following scandals that led to Kurz's resignation) for Thiel Capital in 2022, Jan Böhmermann of the ZDF wrote and performed the satirical song Right time to Thiel that portrayed Thiel as a James Bond villain. Thiel was a German citizen by birth and became an American citizen by naturalization. He received New Zealand citizenship in a private ceremony at the New Zealand consulate in Santa Monica, California, in August 2011; his citizenship status was not made public until 2017. Thiel had visited the country on four occasions prior to his application for citizenship, staying a total of 12 days; the typical residency requirement is 1,350 days in five years. When he applied, Thiel stated he had no intention of living in New Zealand, which is a criterion for citizenship. Then-Minister of Internal Affairs Nathan Guy waived those normal requirements, under an "exceptional circumstances" clause of the Citizenship Act. Thiel's application cited his contribution to the economy—he had founded a venture capital fund in Auckland before applying, and had invested $7 million in two local companies—as well as a $1 million donation to the 2011 Christchurch earthquake appeal fund. Rod Drury, founder of Xero, also provided a formal reference for Thiel's application. Thiel's case was cited by critics as an example of how New Zealand passports can be bought, something the New Zealand government denied. At the time that his citizenship was revealed, The New Zealand Herald came out with the report that the New Zealand Defence Force, the Security Intelligence Service, and the Government Communications and Security Bureau have long-standing links with Thiel's Palantir. In 2015, Thiel purchased a 193-hectare (477-acre) estate near Wānaka, which fit the classification of "sensitive land" and required foreign buyers to obtain permission from New Zealand's Overseas Investment Office. Thiel did not require permission, as he was a citizen. Works In 1995, the Independent Institute published The Diversity Myth: Multiculturalism and the Politics of Intolerance at Stanford, which Thiel co-authored along with fellow tech entrepreneur David O. Sacks, and with a foreword by the late Emory University historian Elizabeth Fox-Genovese. The book is critical of political correctness and multiculturalism in higher education and alleges that it has diluted academic rigor. The authors also argue that, "You don't have diversity when you gather people who look different but talk and think alike."[N 6] Thiel and Sacks's writings drew criticism from then-Stanford Provost Condoleezza Rice and then-Stanford President Gerhard Casper in describing Thiel and Sacks's view of Stanford as "a cartoon, not a description of our freshman curriculum", and their commentary as "demagoguery, pure and simple". In 2016, Thiel apologized for two statements involving the rape crisis movement and date rape that he made in the book. In spring 2012, Thiel taught the class CS 183: Startup at Stanford University. Notes for the course, taken by student Blake Masters, led to a book titled Zero to One: Notes on Startups, or How to Build the Future by Thiel and Masters, which was released in September 2014. Derek Thompson, writing for The Atlantic, stated Zero to One "might be the best business book I've read". He described it as a "self-help book for entrepreneurs, bursting with bromides" but also as a "lucid and profound articulation of capitalism and success in the 21st century economy." "The Straussian Moment" is an essay written by Thiel in 2004, sometimes considered to be a fundamental text in his political thinking and was the subject of a 2019 interview at the Hoover Institution. The essay draws on several thinkers and political theorists and argues that the September 11 attacks upset "the entire political and military framework of the nineteenth and twentieth centuries", and therefore "a reexamination of the foundations of modern politics" was needed. One of Thiel's favorite books is The Sovereign Individual, which was a little-known work before he helped to popularize it. He wrote the preface for the reprinted edition. Thiel also has a chapter giving advice in Tim Ferriss self-help book Tools of Titans: The Tactics, Routines, and Habits of Billionaires, Icons, and World-Class Performers. Notes References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/East_Thrace] | [TOKENS: 1298] |
Contents East Thrace East Thrace or Eastern Thrace,[a] also known as Turkish Thrace or European Turkey, is the part of Turkey that is geographically in Southeast Europe. Turkish Thrace accounts for 3.03% of Turkey's land area and 15% of its population. The largest city is Istanbul, which straddles the Bosporus between Europe and Asia. East Thrace is of historic importance as it is next to a major sea trade corridor and constitutes what remains of the once-vast Ottoman region of Rumelia. It is currently also of specific geostrategic importance because the sea corridor, which includes two narrow straits, provides access to the Mediterranean Sea from the Black Sea for the navies of five countries: Russia, Ukraine, Romania, Bulgaria, and Georgia. The region also serves as a future connector of existing Turkish, Bulgarian, and Greek high-speed rail networks. Due to the guest worker agreement with Turkey and Germany, some Turks in Germany originally come from Eastern Thrace, mostly from the Kırklareli Province. Definition East Thrace sometimes refers to the eastern part of the historical region of Thrace. It is also used for the part of Thrace that is inside Turkey. The area includes all the territories of the Turkish provinces of Edirne, Tekirdağ and Kırklareli, as well as those territories on the European continent of the provinces of Çanakkale and Istanbul. The land borders of East Thrace were defined by the Treaty of Constantinople (1913) and the Bulgarian-Ottoman convention (1915) and were reaffirmed by the Treaty of Lausanne. Geography East Thrace has an area of 23,757 km2 (9,172 sq mi), 3.1% of Turkey's internal area; the population density is around 515/km2, compared to about 98/km2 for Asiatic Turkey. The two continents are separated by the Dardanelles, the Bosphorus (collectively known as the Turkish straits) and the Sea of Marmara, a route of about 361 km (224 mi). The southernmost part of eastern Thrace is called the Gallipoli peninsula. East Thrace is bordered on the west by Greece and on the north by Bulgaria, with the Aegean Sea to the southwest and the Black Sea to the northeast. Climate The area has a hybrid mediterranean climate/humid subtropical climate on the Aegean Sea coast and the Marmara Sea coast, and an oceanic climate on the Black Sea coast. Summers are warm to hot, humid and moderately dry whereas winters are cold and wet and sometimes snowy. The coastal climate keeps the temperatures relatively mild. History East Thrace was the setting for several important events in history and legend, including: During the Russo-Turkish War (1877–1878) and the Balkan Wars (1912–1913), Muslim Muhacir of various ethnic groups from the former Ottoman territories in the Balkans, were forced to flee toward eastern Thrace through expulsions, violence and massacres, followed by further emigration caused by the 1923–24 Population exchange between Greece and Turkey. Prior to that the distribution of ethnoreligious groups in the local sanjaks was as follows: The Muslim millet was recorded as Turkish, while the church members of the Ecumenical Patriarchate were recorded as Greek. In the past century, modern East Thrace was the main component of the territory of the Adrianople Vilayet, which excluded the Constantinople Vilayet, but included West Thrace and parts of the Rhodopes and Sakar. A publication from December 21, 1912, in the Belgian magazine Ons Volk Ontwaakt (‘Our Nation Awakes’) estimated 1,006,500 inhabitants in the vilayet: 21st century East Thrace constitutes what remains of Turkish Rumelia, which once stretched as far north as Hungary and as far west as Bosnia. Rumelia was lost piecemeal from 1699 onwards, until in 1912 the bulk of it was lost in the First Balkan War. Some small regains were made during the Second Balkan War. The current borders were set forth in the Treaty of Constantinople (1913) and the Bulgarian–Ottoman convention (1915), and were reaffirmed in the Treaty of Lausanne. Demographics Huge chunk of the population are descendants of the Muhacir, such as Balkan Turks, Bulgarian Turks in Turkey, Amuca tribe, Albanians in Turkey, Bosniaks in Turkey, Gajal, Pomaks in Turkey, Megleno-Romanians, Vallahades, Crimean Tatars in Turkey, Circassians in Turkey, and Romani people in Turkey live there. Attractions and festivals Some tourist attractions are the Edirne Museum, Complex of Sultan Bayezid II Health Museum, Treaty of Lausanne Monument and Museum, Kırklareli Museum, and the Edirne Palace. There are several historical religious buildings, such as the Selimiye Mosque, Üç Şerefeli Mosque, Old Mosque, Muradiye Mosque, and the Grand Synagogue of Edirne. There are also historical bridges, such as the Fatih Bridge, Meriç Bridge, and Uzunköprü Bridge. Natural attractions include the Lake Gala National Park, İğneada Floodplain Forests National Park, Lake Saka Nature Reserve, and Dupnisa Cave. Since 1360, the oil wrestling tournament Kırkpınar is held annually near Edirne; usually in late June. The Romani festival Kakava is held annually in Edirne and Kırklareli. Politics In Eastern Thrace the Republican People's Party and Kemalism traditionally dominate. A scandal in Turkey was triggered by the statement of CHP Büyükçekmece Council Member Eren Savaş in May 2023 that Eastern Thrace should be separated from Turkey. Gallery See also Notes References Further reading 41°9′13″N 27°22′0″E / 41.15361°N 27.36667°E / 41.15361; 27.36667 |
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[SOURCE: https://en.wikipedia.org/wiki/Antikythera] | [TOKENS: 1187] |
Contents Antikythera Antikythera (/ˌæntɪkɪˈθɪərə/ AN-tik-ih-THEER-ə, US also /ˌæntaɪkɪˈ-/ AN-ty-kih-; Modern Greek: Αντικύθηρα, romanized: Antikýthira, IPA: [andiˈciθira])[note 1] or Anticythera, known in antiquity as Aigilia (Αἰγιλία), is a Greek island lying on the edge of the Aegean Sea, between Crete and Peloponnese. Since the 2011 local government reform, it is part of the municipality of Kythira island. North of Antikythera is the Kythira-Antikythira Strait, through which Mediterranean water enters the Sea of Crete. Its land area is 20.43 square kilometres (7.89 square miles), and it lies 38 kilometres (24 miles) south-east of Kythira. It is the most distant part of the Attica region from its heart in the Athens metropolitan area. It is lozenge-shaped, 10.5 km (6.5 mi) NNW to SSE by 3.4 km (2.1 mi) ENE to WSW. It is notable for being the location of the discovery of the Antikythera mechanism and for the historical Roman-era Antikythera wreck. Its main settlement and port is Potamós (pop. 34 inhabitants in the 2011 census). The only other settlements are Galanianá (pop. 15), and Charchalianá (pop. 19). Antikythera is periodically visited by the Ablemon Nautical Company ferry F/B Ionis on its route between Piraeus (Athens) and Kissamos-Kastelli on Crete. History The earliest known inhabitants (5th or 4th millennium BC) were likely seasonal hunters who traveled there to exploit the presence of migratory birds. The population of the island then changed frequently as it was settled and abandoned several times, including a period of significant influence by Cretan culture during the Bronze Age. In antiquity, the island of Antikythera was known as Aegilia or Aigilia (Αἰγιλία), Aegila or Aigila (Αἴγιλα), or Ogylos (Ὤγυλος). Between the 4th and 1st centuries BC, it was used as a base by a group of Cilician pirates until their destruction by Pompey the Great. Their fort can still be seen atop a cliff to the northeast of the island. The archaeology of the island has been thoroughly surveyed and the data made openly available for further study. Antikythera is one of the few islands in the Aegean which were never ruled by the Ottoman Empire, as the Ottomans did not consider the small island a worthwhile conquest. Nevertheless, it was noted on Ottoman maps as Küçük Çuha, a name that has persisted in modern Turkish. Antikythera, known as Cerigotto in Italian, was administered by the Venetians as part of the Ionian Islands, despite being several hundred kilometres away from the main Ionian archipelago. The Venetians held out in Antikythera until 1800 while the rest of the Ionian Islands had fallen to Napoleonic France in 1797. It became a British protectorate in 1815 as part of the United States of the Ionian Islands. The island was then ceded to Greece under the Treaty of London (1864). From 1864 to 1912, Antikythera was the southernmost point of Greece, as Crete and the surrounding islands including Gavdos were then part of the Ottoman Empire. Antikythera is most famous for being the location of the 1900 discovery of the Antikythera wreck, from which the Antikythera Ephebe and Antikythera mechanism were recovered. The Antikythera mechanism is an ancient mechanical calculator (sometimes described as the first mechanical computer) designed to calculate astronomical positions which has been dated to about 205 BC. Technological artifacts of similar complexity did not reappear until a thousand years later. Fauna Antikythera is a very important stop-over site for migratory birds during their seasonal movements, due to its geographical position and certain features (a longitudinal island, with a north–south direction and very low human impact). Furthermore, the island hosts the largest breeding colony of Eleonora's falcon (Falco eleonorae) in the world. The importance of Antikythera for studying bird migration led to the creation of Antikythera Bird Observatory (A.B.O) by the Hellenic Ornithological Society. The island, along with its associated islets, has been recognised as an Important Bird Area (IBA) by BirdLife International. The island also has a large population of wild goats. Climate Observation Center (PANGEA) Following an agreement among European Investment Bank, the Kithira-Antikithira Commission of Inland Property, the National Observatory of Athens, the Municipality and the Greek Public, a total fund of 25m euros will be used to install one of the largest Climate Observatory Centers in Europe. The project has also gained the support of Cosmote and Niarchos Foundation. Notable people References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Talmud] | [TOKENS: 12049] |
Contents Talmud The Talmud (/ˈtɑːlmʊd, -məd, ˈtæl-/; Hebrew: תַּלְמוּד, romanized: Talmūḏ, 'study' or 'learning') is the central text of Rabbinic Judaism and second in authority only to the Hebrew Bible (Tanakh), the first five books of which form the Torah. It is a primary source of Jewish law (הֲלָכָה, Halakha) and Jewish theology. It consists of the part of the Oral Torah compiled in the Mishnah and its commentaries, the Gemara. It records the teachings, opinions and disagreements of thousands of rabbis and Torah scholars—collectively referred to as Chazal—on a variety of subjects, including Halakha, Jewish ethics, philosophy, customs, history, and folklore among other topics. Until the Haskalah in the 18th and 19th centuries, the Talmud was the centerpiece of Jewish culture in nearly all communities and foundational to "all Jewish thought and aspirations", serving also as "the guide for the daily life" of Jews. "Talmud" is used interchangeably with "Gemara".[a] The text is made up of 63 tractates, each covering one subject area. The language of the Talmud is Jewish Babylonian Aramaic. Talmudic tradition emerged and was compiled between the destruction of the Second Temple in 70 CE and the Arab conquest in the early seventh century. Traditionally, it is thought that the Talmud itself was compiled by Rav Ashi and Ravina II around 500 CE, although it is more likely that this happened in the middle of the sixth century. The word "Talmud" commonly refers to the Babylonian Talmud (Talmud Bavli), not the earlier Jerusalem Talmud (Talmud Yerushalmi). The Babylonian Talmud is the more extensive of the two and is considered the more important. Etymology Talmud translates as "instruction, learning", from the Semitic root lmd, meaning "teach, study". The two Talmuds In antiquity, the two major centres of Jewish scholarship were the Talmudic academies in Syria Palaestina and Babylonia. A Talmud was compiled in each of these regional centres. The earlier of the two compilations took place in Galilee, either in the late fourth or early fifth century, and it came to be known as the Jerusalem Talmud (Jewish Palestinian Aramaic: תַּלְמוּד יְרוּשַׁלְמִי, romanized: Talmud Yerushalmi). Later, and likely some time in the sixth century, the Babylonian Talmud was compiled (Jewish Babylonian Aramaic: תַּלְמוּד בַּבְלִי, romanized: Talmud Bavli). The latter Talmud is usually what is meant when the word "Talmud" is used without qualification. Traditions of the Jerusalem Talmud and its sages had a significant influence on the milieu out of which the Babylonian Talmud arose. The Jerusalem Talmud is known by several other names, including the Palestinian Talmud (which is more accurate, given that it was not compiled in Jerusalem), and the Talmud of the Land of Israel (Talmuda de-Eretz Yisrael or Talmud Eretz Yisrael). The Jerusalem Talmud was a written codification of oral tradition that had been circulating for centuries, representing a compilation of the Palestinian rabbis' teachings about and textual analyses of the Mishnah (especially those concerning agricultural laws) found across regional centres of the Land of Israel in the Galilee (principally those of Tiberias, Sepphoris, and Caesarea). It is written largely in Jewish Palestinian Aramaic, a Western Aramaic language that differs from Jewish Babylonian Aramaic, its Babylonian counterpart. The compilation was likely made between the late fourth to the first half of the fifth century. Despite its incomplete state, the Jerusalem Talmud remains an indispensable source for the study of the development of Halakha in the Holy Land. It was also an important primary source for the study of the Babylonian Talmud by the Kairouan school of Chananel ben Chushiel and Nissim ben Jacob, with the result being that opinions ultimately based on the Jerusalem Talmud found their way into the Tosafot and the Mishneh Torah by Maimonides. Ethical maxims in the Jerusalem Talmud are scattered and interspersed throughout the legal discussions of the several treatises, many of which differ from those in the Babylonian Talmud. The Babylonian Talmud (Talmud Bavli) consists of documents compiled over the period of late antiquity (3rd to 6th centuries). During this period, the most important of the Mesopotamian Jewish centres of learning included the Talmudic academies in Babylonia, such as Nehardea, Nisibis (now Nusaybin), Mahoza (al-Mada'in, south of modern Baghdad), Pumbedita (near present-day al Anbar Governorate), and the Sura Academy, which was probably located about 60 km (37 mi) south of Baghdad. The Babylonian Talmud is the culmination of centuries of analysis and dialectic of the Mishnah and Hebrew Bible in the Talmudic academies in Babylonia. According to tradition, the foundations of this process of analysis were laid by Abba Arika (175–247), a disciple of Judah ha-Nasi. Tradition ascribes the compilation of the Babylonian Talmud in its present form to two Babylonian sages, Rav Ashi and Ravina II. Rav Ashi was the president of the Sura Academy from 375 to 427. At this time, he began compiling the Talmud, a written project passed on and completed by Ravina II, the final Amoraic expounder of the Oral Torah. Traditionally, the latest year for the compilation of the Talmud is typically placed at 475, the year Ravina II died. However, even among those who hold traditional views, a final redaction is still thought to have been made by the Savoraim (Jewish Babylonian Aramaic: סָבוֹרָאִים, lit. 'Reasoners') in the sixth century. Unlike the Western Aramaic dialect of the Jerusalem Talmud, the Babylonian Talmud uses a Babylonian Aramaic dialect. The Jerusalem is also more fragmentary (and difficult to read) due to an incomplete redaction process. Discussions in the Babylonian Talmud are more discursive, rambling, and rely more heavily on anecdote and argumentation by syllogism and Inductive reasoning; those in the Jerusalem Talmud are more factual and apply argumentation through logical deductive reasoning. The Babylonian Talmud is much longer, with about 2.5 million words in total. Proportionally more of the Babylonian material is non-halakhic Aggadah (אַגָּדָה, 'legend'), constituting a third of its material, compared to a sixth of the Jerusalem. The Babylonian Talmud has received significantly more interest and coverage from commentators. Maimonides drew influence from both Babylonian and Jerusalem Talmuds, although he favored the latter over the former when principles between them conflicted. As the Palestinian Jewish community declined in influence and the Babylonian community became the intellectual center of the Jewish diaspora, the Babylonian Talmud became the more widely accepted and popular version. Whereas the Jerusalem Talmud only includes the opinions of Palestinian rabbis (the Ma'arava), the Babylonian Talmud also includes Babylonian authorities (in addition to later authorities because of its later date). As such, it is regarded as more comprehensive. Neither Talmud covers the entire Mishnah. For example, the Babylonian commentary only covers 37 of 63 Mishnaic tractates. In particular: Structure The structure of the Talmud follows that of the Mishnah, divided into Six Orders (known as the Shisha Sedarim, or Shas) of general subject matter are divided into 63 tractates (masekhtot; singular: masekhet) of more focused subject compilations, though not all tractates have Gemara. Each tractate is divided into chapters (perakim; singular: perek), 517 in total, that are both numbered according to the Hebrew alphabet and given names, usually using the first one or two words in the first Mishnah. A perek may continue over several (up to tens of) pages. Each perek will contain several mishnayot. The Mishnah is a compilation of legal opinions and debates. Statements in the Mishnah are typically terse, recording brief opinions of the rabbis debating a subject; or recording only an unattributed ruling, apparently representing a consensus view. The rabbis recorded in the Mishnah are known as the Tannaim (literally, "repeaters", or "teachers"). These tannaim—rabbis of the second century CE—"who produced the Mishnah and other tannaic works, must be distinguished from the rabbis of the third to fifth centuries, known as amoraim (literally, "speakers"), who produced the two Talmudim and other amoraic works". Since it sequences its laws by subject matter instead of by biblical context, the Mishnah discusses individual subjects more thoroughly than the Midrash, and it includes a much broader selection of halakhic subjects than the Midrash. The Mishnah's topical organization thus became the framework of the Talmud as a whole. But not every tractate in the Mishnah has a corresponding Gemara. Also, the order of the tractates in the Talmud differs in some cases from that in the Mishnah. The Gemara is broadly speaking a commentary on the Mishnah. This commentary arises from a longstanding tradition of rabbis analyzing, debating, and discussing the Mishnah—shakla v'tarya—ever since it was compiled. The rabbis who participated in the process that produced this commentarial tradition are known as the Amoraim. Each discussion is presented in a self-contained, edited passage known as a sugya. Much of the Gemara is legal in nature. Each analysis begins with a Mishnaic legal statement. With each sugya, the statement may be analyzed and compared with other statements. This process can be framed as an exchange between two (often anonymous, possibly metaphorical) disputants, termed the makshan (questioner) and tartzan (answerer). Gemara also commonly tries to find the correct biblical basis for a given law in the Mishnah as well as the logical process that connects the biblical to the Mishnaic tradition. This process was known as talmud, long before the "Talmud" itself became a text. In addition, the Gemara contains a wide range of narratives, homiletical or exegetical passages, sayings, and other non-legal content, termed aggadah. A story told in a sugya of the Babylonian Talmud may draw upon the Mishnah, the Jerusalem Talmud, midrash, and other sources. The traditions that the Gemara comments on are not limited to what is found in the Mishnah, but the Baraita as well (a term that broadly designates Oral Torah traditions that did not end up in the Mishnah). The baraitot cited in the Gemara are often quotations from the Tosefta (a tannaitic compendium of halakha parallel to the Mishnah) and the Midrash halakha (specifically Mekhilta, Sifra and Sifre). Some baraitot, however, are known only through traditions cited in the Gemara, and are not part of any other collection. In addition to the Six Orders, the Talmud contains a series of short treatises of a later date, usually printed at the end of Seder Nezikin. These are not divided into Mishnah and Gemara. Language The work is largely in Jewish Babylonian Aramaic, although quotations in the Gemara of the Mishnah, the Baraitas and Tanakh appear in Mishnaic or Biblical Hebrew. Some other dialects of Aramaic occur in quotations of other older works, like the Megillat Taanit. The reason why earlier texts occur in Hebrew, and later texts in Aramaic, is because of the adoption of the latter (which was the spoken vernacular) by rabbinic circles during the period of the Amoraim (rabbis cited in the Gemara) beginning around the year 200. A second Aramaic dialect is used in Nedarim, Nazir, Temurah, Keritot, and Me'ilah; the second is closer in style to the Targum. Manuscripts The only complete manuscript of the Talmud, Munich Codex Hebraica 95, dates from 1342 (view scan). Other manuscripts of the Talmud include: Dating The Talmud itself (BM 86a) incorporates a statement that "Ravina and Rav Ashi were the end of instruction". Likewise, Sherira ben Hanina writes that "instruction ended" with the death of Ravina II in 811 SE (500 CE), and "the Talmud stopped with the end of instruction in the days of Rabbah Jose (fl. 476–514)". Seder Olam Zutta records that "in 811 SE (500 CE) Ravina the End of Instruction died, and the Talmud was stopped", and the same text is found in Codex Gaster 83. Another medieval chronicle records that "On Wednesday, 13 Kislev, 811 SE (500 CE), Ravina the End of Instruction son of Rav Huna died, and the Talmud stopped." Abraham ibn Daud gives 821 SE (510 CE) for the same event, and Joseph ibn Tzaddik writes that "Mareimar and Mar bar Rav Assi et al. completed the Babylonian Talmud ... in 4265 AM (505 CE)". Nachmanides dated the Talmud's compilation to "400 years after the Destruction", which is 470 CE if taken as exact. According to Moses da Rieti, "Ravina and Rav Ashi compiled the Talmud but they did not complete it, and Mar bar Rav Ashi and Mareimar et al. sealed it in the days of Rabbah Jose ... he headed the academy for 38 years after succeeding Ravina, until 4274 AM (514 CE), and in his days the Babylonian Talmud was sealed, which was begun and largely redacted in the days of Rav Ashi and Ravina". The Wikkuah, a description of the 1240 Disputation of Paris, records that Yechiel of Paris claimed that "the Talmud is 1,500 years old", which would put it in the 3rd century BCE. Pietro Capelli suggests that it must have been traditional among medieval Ashkenazic Jews to date the Talmud from its beginning instead of its completion. Later manuscripts of the Wikkuah adopt the usual system of dating it to the time of Ravina II. Nicholas Donin, by contrast, claimed that the Talmud was only composed "400 years" before, i.e. around 840 CE. A wide range of dates have been proposed for the Babylonian Talmud by historians. The text was most likely completed, however, in the 6th century, or prior to the early Muslim conquests in the mid-7th century at the latest, on the basis that the Talmud lacks loanwords or syntax deriving from Arabic. By comparison, Islamic-era rabbinic documents are heavily influenced by Arabic writing, convention, and loanwords, and rabbinic writings came to be exclusively written in Arabic by the 8th century. Recently,[when?] it has been extensively argued that Talmud is an expression and product of Sasanian culture, as well as other Greek-Roman, Middle Persian, and Syriac sources up to the same period of time. The contents of the text likely trace to this time regardless of the date of the final redaction/compilation. Additional external evidence for a latest possible date for the composition of the Babylonian Talmud are uses of it by external sources such as Letter of Baboi (c. 813) and chronicles like the Seder Tannaim veAmoraim (9th century) and the Iggeret of Rabbi Sherira Gaon (987). As for the earliest possible date of the Babylonian Talmud, it must post-date the early 5th century given its reliance on the Jerusalem Talmud. In Jewish scholarship From the time of its completion, the Talmud became integral to Jewish scholarship. A maxim in Pirkei Avot advocates its study from the age of 15. Rabbi Adin Steinsaltz writes that "If the Bible is the cornerstone of Judaism, then the Talmud is the central pillar ... No other work has had a comparable influence on the theory and practice of Jewish life, shaping influence on the theory and practice of Jewish life" and states: The Talmud is the repository of thousands of years of Jewish wisdom, and the oral law, which is as ancient and significant as the written law (the Torah) finds expression therein. It is a conglomerate of law, legend, and philosophy, a blend of unique logic and shrewd pragmatism, of history and science, anecdotes and humor ... Although its main objective is to interpret and comment on a book of law, it is, simultaneously, a work of art that goes beyond legislation and its practical application. And although the Talmud is, to this day, the primary source of Jewish law, it cannot be cited as an authority for purposes of ruling ... Though based on the principles of tradition and the transmission of authority from generation to generation, it is unparalleled in its eagerness to question and reexamine convention and accepted views and to root out underlying causes. The talmudic method of discussion and demonstration tries to approximate mathematical precision, but without having recourse to mathematical or logical symbols. ... the Talmud is the embodiment of the great concept of mitzvat talmud Torah – the positive religious duty of studying Torah, of acquiring learning and wisdom, study which is its own end and reward. The following subsections outline some of the major areas of Talmudic study. One area of Talmudic scholarship developed out of the need to ascertain the Halakha (Jewish rabbinical law). Early commentators such as Isaac Alfasi (North Africa, 1013–1103) attempted to extract and determine the binding legal opinions from the vast corpus of the Talmud. Alfasi's work was highly influential, attracted several commentaries in its own right and later served as a basis for the creation of halakhic codes. Another influential medieval Halakhic work following the order of the Babylonian Talmud, and to some extent modelled on Alfasi, was "the Mordechai", a compilation by Mordechai ben Hillel (c. 1250–1298). A third such work was that of Asher ben Yechiel (d. 1327). All these works and their commentaries are printed in the Vilna and many subsequent editions of the Talmud. A 15th-century Spanish rabbi, Jacob ibn Habib (d. 1516), compiled the Ein Yaakov, which extracts nearly all the Aggadic material from the Talmud. It was intended to familiarize the public with the ethical parts of the Talmud and to dispute many of the accusations surrounding its contents. Geonic-era (6th-11th centuries) commentaries have largely been lost, but are known to exist from partial quotations in later medieval and early modern texts. Because of this, it is known that now-lost commentaries on the Talmud were written by Paltoi Gaon, Sherira, Hai Gaon, and Saadya (though in this case, Saadiya is not likely to be the true author). Of these, the commentary of Paltoi ben Abaye (c. 840) is the earliest. His son, Zemah ben Paltoi paraphrased and explained the passages which he quoted; and he composed, as an aid to the study of the Talmud, a lexicon which Abraham Zacuto consulted in the fifteenth century. Saadia Gaon is said to have composed commentaries on the Talmud, aside from his Arabic commentaries on the Mishnah. The first surviving commentary on the entire Talmud is that of Chananel ben Chushiel. Many medieval authors also composed commentaries focusing on the content of specific tractates, including Nissim ben Jacob and Gershom ben Judah. The commentary of Rashi, covering most of the Talmud, has become a classic. Sections in the commentary covering a few tractates (Pes, BB and Mak) were completed by his students, especially Judah ben Nathan, and a sections dealing with specific tractates (Ned, Naz, Hor and MQ) of the commentary that appear in some print editions of Rashi's commentary today were not composed by him. In the twelfth and thirteenth centuries, a genre of rabbinic literature emerged surrounding Rashi's commentary, with the purpose of supplementing it and addressing internal contradictions via the technique of pilpul. This genre of commentary is known as the Tosafot and focuses on specific passages instead of a running continuous commentary across the entire Talmud. Many Talmudic passages are difficult to understand, sometimes owing to the use of Greek or Persian loanwords whose meaning had become obscure. A major area of Talmudic scholarship developed to explain these passages and words. Some early commentators such as Rabbenu Gershom of Mainz (10th century) and Rabbenu Ḥananel (early 11th century) produced running commentaries to various tractates. These commentaries could be read with the text of the Talmud and would help explain the meaning of the text. Another important work is the Sefer ha-Mafteaḥ (Book of the Key) by Nissim Gaon, which contains a preface explaining the different forms of Talmudic argumentation and then explains abbreviated passages in the Talmud by cross-referring to parallel passages where the same thought is expressed in full. Commentaries (ḥiddushim) by Joseph ibn Migash on two tractates, Bava Batra and Shevuot, based on Ḥananel and Alfasi, also survive, as does a compilation by Zechariah Aghmati called Sefer ha-Ner. The Tosafot are collected commentaries by various medieval Ashkenazic rabbis on the Talmud (known as Tosafists or Ba'alei Tosafot). One of the main goals of the Tosafot is to explain and interpret contradictory statements in the Talmud. Unlike Rashi, the Tosafot is not a running commentary, but rather comments on selected matters. Often the explanations of Tosafot differ from those of Rashi. Among the founders of the Tosafist school were Rabbeinu Tam, who was a grandson of Rashi, and, Rabbenu Tam's nephew, Isaac ben Samuel. The Tosafot commentaries were collected in different editions in the various schools. The benchmark collection of Tosafot for Northern France was that of Eliezer of Touques. The standard collection for Spain was Rabbenu Asher's Tosefot haRosh. The Tosafot that are printed in the standard Vilna edition of the Talmud are an edited version compiled from the various medieval collections, predominantly that of Touques.[full citation needed] Over time, the approach of the Tosafists spread to other Jewish communities, particularly those in Spain. This led to the composition of many other commentaries in similar styles. Among these are the commentaries of Nachmanides (Ramban), Solomon ben Adret (Rashba), Yom Tov of Seville (Ritva) and Nissim of Gerona (Ran); these are often titled “Chiddushei ...” (“Novellae of ...”). A comprehensive anthology consisting of extracts from all these is the Shitah Mekubezet of Bezalel Ashkenazi. Other commentaries produced in Spain and Provence were not influenced by the Tosafist style. Two of the most significant of these are the Yad Ramah by rabbi Meir Abulafia and Bet Habechirah by rabbi Menahem haMeiri, commonly referred to as "Meiri". While the Bet Habechirah is extant for all of Talmud, we only have the Yad Ramah for Tractates Sanhedrin, Baba Batra and Gittin. Like the commentaries of Ramban and the others, these are generally printed as independent works, though some Talmud editions include the Shitah Mekubezet in an abbreviated form. In later centuries, focus partially shifted from direct Talmudic interpretation to the analysis of previously written Talmudic commentaries. Well known are "Maharshal" (Solomon Luria), "Maharam" (Meir Lublin) and "Maharsha" (Samuel Edels), which analyze Rashi and Tosafot together; other such commentaries include Ma'adanei Yom Tov by Yom-Tov Lipmann Heller, in turn a commentary on the Rosh (see below), and the glosses by Zvi Hirsch Chajes. These later commentaries are generally appended to the tractate. Commentaries discussing the Halachik-legal content – outlined above – include "Rosh", "Rif" and "Mordechai"; these are now standard appendices to each volume. Rambam's Mishneh Torah is invariably studied alongside these three; although a code, and therefore not in the same order as the Talmud, the relevant location is identified via the Ein Mishpat, following. (A recent project, Halacha Brura, founded by Abraham Isaac Kook, presents the Talmud and a summary of the halachic codes side by side, so as to enable the collation of Talmud with resultant Halacha.) Found in almost all editions of the Talmud, is the "study-aid" consisting of the marginal notes Torah Or, Ein Mishpat Ner Mitzvah and Masoret ha-Shas by the Italian rabbi Joshua Boaz, which give references respectively: to the cited Biblical passages, to the relevant halachic codes (Mishneh Torah, Tur, Shulchan Aruch, and Se'mag) and to related Talmudic passages. Most editions of the Talmud include also the brief marginal notes by Akiva Eger under the name Gilyon ha-Shas, and textual notes by Joel Sirkes and the Vilna Gaon. During the 15th and 16th centuries, a new intensive form of Talmud study arose. Complicated logical arguments were used to explain minor points of contradiction within the Talmud. The term pilpul was applied to this type of study. Usage of pilpul in this sense (that of "sharp analysis") harks back to the Talmudic era and refers to the intellectual sharpness this method demanded. Pilpul practitioners posited that the Talmud could contain no redundancy or contradiction whatsoever. New categories and distinctions (hillukim) were therefore created, resolving seeming contradictions within the Talmud by novel logical means. In the Ashkenazi world the founders of pilpul are generally considered to be Jacob Pollak (1460–1541) and Shalom Shachna. This kind of study reached its height in the 16th and 17th centuries when expertise in pilpulistic analysis was considered an art form and became a goal in and of itself within the yeshivot of Poland and Lithuania. But the popular new method of Talmud study was not without critics; already in the 15th century, the ethical tract Orhot Zaddikim ("Paths of the Righteous" in Hebrew) criticized pilpul for an overemphasis on intellectual acuity. Many 16th- and 17th-century rabbis were also critical of pilpul. Among them are Judah Loew ben Bezalel (the Maharal of Prague), Isaiah Horowitz, and Yair Bacharach. By the 18th century, pilpul study waned. Other styles of learning such as that of the school of Elijah b. Solomon, the Vilna Gaon, became popular. The term "pilpul" was increasingly applied derogatorily to novellae deemed casuistic and hairsplitting. Authors referred to their own commentaries as "al derekh ha-peshat" (by the simple method) to contrast them with pilpul.[full citation needed] Among Sephardi and Italian Jews from the 15th century on, some authorities sought to apply the methods of Aristotelian logic, as reformulated by Averroes. This method was first recorded, though without explicit reference to Aristotle, by Isaac Campanton (d. Spain, 1463) in his Darkhei ha-Talmud ("The Ways of the Talmud"), and is also found in the works of Moses Chaim Luzzatto. According to the present-day Sephardi scholar José Faur, traditional Sephardic Talmud study could take place on any of three levels. In the late 19th century another trend in Talmud study arose. Hayyim Soloveitchik (1853–1918) of Brisk (Brest-Litovsk) developed and refined this style of study. Brisker method involves a reductionistic analysis of rabbinic arguments within the Talmud or among the Rishonim, explaining the differing opinions by placing them within a categorical structure. The Brisker method is highly analytical and is often criticized as being a modern-day version of pilpul. Nevertheless, the influence of the Brisker method is great. Most modern-day Yeshivot study the Talmud using the Brisker method in some form. One feature of this method is the use of Maimonides' Mishneh Torah as a guide to Talmudic interpretation, as distinct from its use as a source of practical halakha. Rival methods were those of the Mir and Telz yeshivas. See Chaim Rabinowitz § Telshe and Yeshiva Ohel Torah-Baranovich § Style of learning. Textual criticism The text of the Talmud has been subject to some level of critical scrutiny throughout its history. Rabbinic tradition holds that the people cited in both Talmuds did not have a hand in its writings; rather, their teachings were edited into a rough form around 450 CE (Talmud Yerushalmi) and 550 CE (Talmud Bavli). The text of the Bavli especially was not firmly fixed at that time. Gaonic responsa literature addresses this issue. Teshuvot Geonim Kadmonim, section 78, deals with mistaken biblical readings in the Talmud. This Gaonic responsum states: But you must examine carefully in every case when you feel uncertainty [as to the credibility of the text] – what is its source? Whether a scribal error? Or the superficiality of a second rate student who was not well versed? ... after the manner of many mistakes found among those superficial second-rate students, and certainly among those rural memorizers who were not familiar with the biblical text. And since they erred in the first place ... [they compounded the error.] — Teshuvot Geonim Kadmonim, Ed. Cassel, Berlin 1858, Photographic reprint Tel Aviv 1964, 23b. In the early medieval era, Rashi already concluded that some statements in the extant text of the Talmud were insertions from later editors. On Shevuot 3b Rashi writes "A mistaken student wrote this in the margin of the Talmud, and copyists [subsequently] put it into the Gemara."[b] The emendations of Yoel Sirkis and the Vilna Gaon are included in all standard editions of the Talmud, in the form of marginal glosses entitled Hagahot ha-Bach and Hagahot ha-Gra respectively; further emendations by Solomon Luria are set out in commentary form at the back of each tractate. The Vilna Gaon's emendations were often based on his quest for internal consistency in the text rather than on manuscript evidence; nevertheless many of the Gaon's emendations were later verified by textual critics, such as Solomon Schechter, who had Cairo Genizah texts with which to compare our standard editions. In the 19th century, Raphael Nathan Nota Rabinovicz published a multi-volume work entitled Dikdukei Soferim, showing textual variants from the Munich and other early manuscripts of the Talmud, and further variants are recorded in the Complete Israeli Talmud and Gemara Shelemah editions (see § Critical editions, above). Today many more manuscripts have become available, in particular from the Cairo Geniza. The Academy of the Hebrew Language has prepared a text on CD-ROM for lexicographical purposes, containing the text of each tractate according to the manuscript it considers most reliable, and images of some of the older manuscripts may be found on the website of the National Library of Israel (formerly the Jewish National and University Library). The NLI, the Lieberman Institute (associated with the Jewish Theological Seminary of America), the Institute for the Complete Israeli Talmud (part of Yad Harav Herzog) and the Friedberg Jewish Manuscript Society all maintain searchable websites on which the viewer can request variant manuscript readings of a given passage. Some trends within contemporary Talmud scholarship are listed below. Translations There are six contemporary translations of the Talmud into English: Index "A widely accepted and accessible index" was the goal driving several such projects.: Editions The first complete edition of the Babylonian Talmud was printed in Venice by Daniel Bomberg between 1520 and 1523 with the support of Pope Leo X. In addition to the Mishnah and Gemara, Bomberg's edition contained the commentaries of Rashi and Tosafot. Almost all printings since Bomberg have followed the same pagination. Bomberg's edition was considered relatively free of censorship. Ambrosius Frobenius collaborated with the scholar Israel Ben Daniel Sifroni from Italy. His most extensive work was a Talmud edition published, with great difficulty, in 1578–1581. Following Ambrosius Frobenius's publication of most of the Talmud in installments in Basel, Immanuel Benveniste published the whole Talmud in installments in Amsterdam 1644–1648, Although according to Raphael Rabbinovicz the Benveniste Talmud may have been based on the Lublin Talmud and included many of the censors' errors. It is noteworthy due to the inclusion of Avodah Zarah, omitted due to Church censorship from several previous editions, and when printed, often lacking a title page. The edition of the Talmud published by the Szapira brothers in Slavita was published in 1817, and it is particularly prized by many rebbes of Hasidic Judaism. In 1835, after a religious community copyright[attribution needed] was nearly over, and following an acrimonious dispute with the Szapira family, a new edition of the Talmud was printed by Menachem Romm of Vilna. Known as the Vilna Edition Shas, this edition (and later ones printed by his widow and sons, the Romm publishing house) has been used in the production of more recent editions of Talmud Bavli. A page number in the Vilna Talmud refers to a double-sided page, known as a daf, or folio in English; each daf has two amudim labeled א and ב, sides A and B (recto and verso). The convention of referencing by daf is relatively recent and dates from the early Talmud printings of the 17th century, though the actual pagination goes back to the Bomberg edition. Earlier rabbinic literature generally refers to the tractate or chapters within a tractate (e.g. Berachot Chapter 1, ברכות פרק א׳). It sometimes also refers to the specific Mishnah in that chapter, where "Mishnah" is replaced with "Halakha", here meaning route, to "direct" the reader to the entry in the Gemara corresponding to that Mishna (e.g. Berachot Chapter 1 Halakha 1, ברכות פרק א׳ הלכה א׳, would refer to the first Mishnah of the first chapter in Tractate Berachot, and its corresponding entry in the Gemara). However, this form is nowadays more commonly (though not exclusively) used when referring to the Jerusalem Talmud. Nowadays, reference is usually made in format [Tractate daf a/b] (e.g. Berachot 23b, ברכות כג ב׳). Increasingly, the symbols "." and ":" are used to indicate Recto and Verso, respectively (thus, e.g. Berachot 23:, :ברכות כג). These references always refer to the pagination of the Vilna Talmud. The text of the Vilna editions is considered by scholars not to be uniformly reliable, and there have been a number of attempts to collate textual variants. There have been critical editions of particular tractates (e.g., Henry Malter's edition of Ta'anit), but there is no modern critical edition of the whole Talmud. Modern editions such as those of the Oz ve-Hadar Institute correct misprints and restore passages that in earlier editions were modified or excised by censorship but do not attempt a comprehensive account of textual variants. One edition, by Yosef Amar, represents the Yemenite tradition, and takes the form of a photostatic reproduction of a Vilna-based print to which Yemenite vocalization and textual variants have been added by hand, together with printed introductory material. Collations of the Yemenite manuscripts of some tractates have been published by Columbia University. A number of editions have been aimed at bringing the Talmud to a wider audience. Aside from the Steinsaltz and Artscroll/Schottenstein sets there are: Lazarus Goldschmidt published an edition from the "uncensored text" of the Babylonian Talmud with a German translation in 9 volumes (commenced Leipzig, 1897–1909; edition completed, following emigration to England in 1933, by 1936). Twelve volumes of the Babylonian Talmud were published by Mir Yeshiva refugees during the years 1942 thru 1946 while they were in Shanghai. The major tractates, one per volume, were: "Shabbat, Eruvin, Pesachim, Gittin, Kiddushin, Nazir, Sotah, Bava Kama, Sanhedrin, Makot, Shevuot, Avodah Zara" (with some volumes having, in addition, "Minor Tractates"). A Survivors' Talmud was published, encouraged by President Truman's "responsibility toward these victims of persecution" statement. The U.S. Army (despite "the acute shortage of paper in Germany") agreed to print "fifty copies of the Talmud, packaged into 16-volume sets" during 1947–1950. The plan was extended: 3,000 copies, in 19-volume sets. In visual arts Rabbis and Talmudists studying and debating Talmud abound in the art of Austrian painter Carl Schleicher (1825–1903); active in Vienna, especially c. 1859–1871. Reception outside of Judaism The study of Talmud is not restricted to those of the Jewish religion and has attracted interest in other cultures. Christian scholars have long shown interest in the study of the Talmud, which has helped illuminate their own scriptures. The Talmud contains biblical exegesis and commentary on the Tanakh that often clarifies elliptical and esoteric passages. The Talmud contains possible references to Jesus and his disciples, while the Christian canon mentions Talmudic figures and contains teachings that can be paralleled in the Talmud and Midrash. The Talmud provides cultural and historical context to the Gospel and the writings of the Apostles. South Koreans reportedly hope to emulate Jews' high academic standards by studying Jewish literature. Almost every household has a translated copy of a book they call "Talmud", which parents read to their children, and the book is part of the primary-school curriculum. The "Talmud" in this case is usually one of several possible volumes, the earliest translated into Korean from the Japanese. The original Japanese books were created through the collaboration of Japanese writer Hideaki Kase and Marvin Tokayer, an Orthodox American rabbi serving in Japan in the 1960s and 70s. The first collaborative book was 5,000 Years of Jewish Wisdom: Secrets of the Talmud Scriptures, created over a three-day period in 1968 and published in 1971. The book contains actual stories from the Talmud, proverbs, ethics, Jewish legal material, biographies of Talmudic rabbis, and personal stories about Tokayer and his family. Tokayer and Kase published a number of other books on Jewish themes together in Japanese. The first South Korean publication of 5,000 Years of Jewish Wisdom was in 1974, by Tae Zang publishing house. Many different editions followed in both Korea and China, often by black-market publishers. Between 2007 and 2009, Yong-soo Hyun of the Shema Yisrael Educational Institute published a 6-volume edition of the Korean Talmud, bringing together material from a variety of Tokayer's earlier books. He worked with Tokayer to correct errors and Tokayer is listed as the author. Tutoring centers based on this and other works called "Talmud" for both adults and children are popular in Korea and "Talmud" books (all based on Tokayer's works and not the original Talmud) are widely read and known. In 2012, then-Vice President of Iran, Mohammad Reza Rahimi, claimed that the Talmud was the cause of the spread of narcotics in the country. Criticism Historian Michael Levi Rodkinson, in his book The History of the Talmud, wrote that detractors of the Talmud, both during and subsequent to its formation, "have varied in their character, objects and actions" and the book documents a number of critics and persecutors, including Nicholas Donin, Johannes Pfefferkorn, Johann Andreas Eisenmenger, the Frankists, and August Rohling. Many of the attacks come from antisemitic sources such as in modern times Justinas Pranaitis, Elizabeth Dilling, and David Duke. Criticisms also arise from Christian, Muslim, and Jewish sources, such as Israel Shahak, as well as from atheists and skeptics such as Christopher Hitchens and Denis Diderot. Accusations against the Talmud, particularly those from antisemitic sources, include alleged: Scholars point out that many of these criticisms are either outright falsehoods or based on quotations that are misrepresented or taken out of context. Some critics misrepresent the meaning of the Talmud's text; it is a detailed record of discussions that preserved statements by and disagreements among a variety of sages, a record of debate from which rejected statements and opinions were never edited out. At the very time that the Babylonian savoraim put the finishing touches to the redaction of the Talmud, the emperor Justinian issued his edict against deuterosis (doubling, repetition) of the Hebrew Bible. It is disputed whether, in this context, deuterosis means "Mishnah" or "Targum": in patristic literature, the word is used in both senses. Full-scale attacks on the Talmud took place in the 13th century in France, where Talmudic study was then flourishing. In the 1230s Nicholas Donin, a Jewish convert to Christianity, pressed 35 charges against the Talmud to Pope Gregory IX by translating a series of allegedly blasphemous passages about Jesus, Mary or Christianity. There is a quoted Talmudic passage, for example, where a person named Yeshu who some people have claimed is Jesus of Nazareth is sent to Gehenna to be boiled in excrement for eternity. Donin also selected an injunction of the Talmud that permits Jews to kill non-Jews. This led to the Disputation of Paris, which took place in 1240 at the court of Louis IX of France, where four rabbis, including Yechiel of Paris and Moses ben Jacob of Coucy, defended the Talmud against the accusations of Nicholas Donin. The translation of the Talmud from Aramaic to non-Jewish languages stripped Jewish discourse from its covering, something that was resented by Jews as a profound violation. The Disputation of Paris led to the condemnation and the first burning of copies of the Talmud in Paris in 1242.[c] The burning of copies of the Talmud continued.[full citation needed] The Talmud was likewise the subject of the Disputation of Barcelona in 1263 between Nahmanides and Pablo Christiani, a Jewish convert to Christianity, in which they argued whether Jesus was the messiah prophesized in Judaism. This same Pablo Christiani made an attack on the Talmud that resulted in a papal bull against the Talmud and in the first censorship, which was undertaken at Barcelona by a commission of Dominicans, who ordered the cancellation of passages deemed objectionable from a Christian perspective (1264). At the Disputation of Tortosa in 1413, Geronimo de Santa Fé brought forward a number of accusations, including the fateful assertion that the condemnations of "pagans", "heathens", and "apostates" found in the Talmud were, in reality, veiled references to Christians. These assertions were denied by the Jewish community and its scholars, who contended that Judaic thought made a sharp distinction between those classified as heathen or pagan, being polytheistic, and those who acknowledge one true God (such as the Christians) even while worshipping the true monotheistic God incorrectly. Thus, Jews viewed Christians as misguided and in error, but not among the "heathens" or "pagans" discussed in the Talmud. Both Pablo Christiani and Geronimo de Santa Fé, in addition to criticizing the Talmud, also regarded it as a source of authentic traditions, some of which could be used as arguments in favor of Christianity. Examples of such traditions were statements that the Messiah was born around the time of the destruction of the Temple and that the Messiah sat at the right hand of God. In 1415, Antipope Benedict XIII, who had convened the Tortosa disputation, issued a papal bull (which was destined, however, to remain inoperative) forbidding the Jews to read the Talmud, and ordering the destruction of all copies of it. Far more important were the charges made in the early part of the 16th century by the convert Johannes Pfefferkorn, the agent of the Dominicans. The result of these accusations was a struggle in which the emperor and the pope acted as judges, the advocate of the Jews being Johann Reuchlin, who was opposed by the obscurantists; and this controversy, which was carried on for the most part by means of pamphlets, became in the eyes of some a precursor of the Reformation. An unexpected result of this affair was the complete printed edition of the Babylonian Talmud issued in 1520 by Daniel Bomberg at Venice, under the protection of a papal privilege. Three years later, in 1523, Bomberg published the first edition of the Jerusalem Talmud. In 1553, during the heightened tensions of the Counter-Reformation and following the Bragadin-Giustiniani dispute, new attacks were made again the Talmud and the Roman Inquisition advocated the burning of the Talmud. The primary reason was not that the Talmud contained alleged blasphemies but that the Inquisition saw the Talmud as an obstacle in the conversion of Jews to Christianity. Thus, on the New Year, Rosh Hashanah (September 9, 1553) the copies of the Talmud confiscated by a decree of the Inquisition and burned in Campo de' Fiori in Rome. Other burnings took place in other Italian cities, such as the one instigated by Joshua dei Cantori at Cremona in 1559. Censorship of the Talmud and other Hebrew works was introduced by a papal bull issued in 1554; five years later the Talmud was included in the first Index Expurgatorius. In 1564, Pope Pius IV abolished the prohibition against the Talmud, but decreed that it would need to be censored and could not have "Talmud" written on its title page. The convention of referring to the work as "Shas" (shishah sidre Mishnah) instead of "Talmud" dates from this time. The first edition of the expurgated Talmud, on which most subsequent editions were based, appeared at Basel (1578–1581) with the omission of the entire treatise of 'Abodah Zarah and of passages considered inimical to Christianity, together with modifications of certain phrases. In 1581, however, Pope Gregory XIII ordered the confiscation of all Hebrew books including the Talmud and though his successor Sixtus V renounced this policy and preparations were made for a new edition of the Talmud, the successor of Sixtus V, Clement VIII Clement VIII renewed in his bull Cum hebraeorum malitia the 1557 ban on all Hebrew books except the Bible. The increasing study of the Talmud in Poland led to the issue of a complete edition (Kraków, 1602–1605), with a restoration of the original text; an edition containing, so far as known, only two treatises had previously been published at Lublin (1559–1576). After an attack on the Talmud took place in Poland (in what is now Ukrainian territory) in 1757, when Bishop Dembowski, at the instigation of the Frankists, convened a public disputation at Kamieniec Podolski, and ordered all copies of the work found in his bishopric to be confiscated and burned. A "1735 edition of Moed Katan, printed in Frankfurt am Oder" is among those that survived from that era. "Situated on the Oder River, three separate editions of the Talmud were printed there between 1697 and 1739."[attribution needed] The external history of the Talmud includes also the literary attacks made upon it by some Christian theologians after the Reformation since these onslaughts on Judaism were directed primarily against that work, the leading example being Eisenmenger's Entdecktes Judenthum (Judaism Unmasked) (1700). In contrast, the Talmud was a subject of rather more sympathetic study by many Christian theologians, jurists and Orientalists from the Renaissance on, including Johann Reuchlin, John Selden, Petrus Cunaeus, John Lightfoot and Johannes Buxtorf father and son. The Flemish scholar Andreas Masius considered that the attack on the Talmud and Hebrew literature would result in greatest damage to Christianity and that a certain knowledge of rabbinic literature was necessary for Christian studies. The Vilna edition of the Talmud was subject to Russian government censorship, or self-censorship to meet government expectations, though this was less severe than some previous attempts: the title "Talmud" was retained and the tractate Avodah Zarah was included. Most modern editions are either copies of or closely based on the Vilna edition, and therefore still omit most of the disputed passages. Although they were not available for many generations, the removed sections of the Talmud, Rashi, Tosafot and Maharsha were preserved through rare printings of lists of errata, known as Chesronos Hashas ("Omissions of the Talmud"). Many of these censored portions were recovered from uncensored manuscripts in the Vatican Library. Some modern editions of the Talmud contain some or all of this material, either at the back of the book, in the margin, or in its original location in the text. In 1830, during a debate in the French Chamber of Peers regarding state recognition of the Jewish faith, Admiral Verhuell declared himself unable to forgive the Jews whom he had met during his travels throughout the world either for their refusal to recognize Jesus as the Messiah or for their possession of the Talmud.[full citation needed] In the same year the Abbé Chiarini published a voluminous work entitled Théorie du Judaïsme, in which he announced a translation of the Talmud, advocating for the first time a version that would make the work generally accessible, and thus serve for attacks on Judaism: only two out of the projected six volumes of this translation appeared. In a like spirit 19th-century antisemitic agitators often urged that a translation be made; and this demand was even brought before legislative bodies, as in Vienna. The Talmud and the "Talmud Jew" thus became objects of antisemitic attacks, for example in August Rohling's Der Talmudjude (1871), although, on the other hand, they were defended by many Christian students of the Talmud, notably Hermann Strack. Further attacks from antisemitic sources include Justinas Pranaitis' The Talmud Unmasked: The Secret Rabbinical Teachings Concerning Christians (1892) and Elizabeth Dilling's The Plot Against Christianity (1964). The criticisms of the Talmud in many modern pamphlets and websites are often recognizable as verbatim quotations from one or other of these. Historians Will and Ariel Durant noted a lack of consistency between the many authors of the Talmud, with some tractates in the wrong order, or subjects dropped and resumed without reason. According to the Durants, the Talmud "is not the product of deliberation, it is the deliberation itself." The Internet is another source of criticism of the Talmud. The Anti-Defamation League's report on this topic states that antisemitic critics of the Talmud frequently use erroneous translations or selective quotations in order to distort the meaning of the Talmud's text, and sometimes fabricate passages. In addition, the critics rarely provide the full context of the quotations and fail to provide contextual information about the culture that the Talmud was composed in, nearly 2,000 years ago. One such example concerns the line: "If a Jew be called upon to explain any part of the rabbinic books, he ought to give only a false explanation. One who transgresses this commandment will be put to death." This is alleged to be a quote from a book titled Libbre David (alternatively Livore David ). No such book exists in the Talmud or elsewhere. The title is assumed to be a corruption of Dibre David, a work published in 1671. Reference to the quote is found in an early Holocaust denial book, The Six Million Reconsidered by William Grimstad. In addition there have been fabricated interpretations such as the 19th-century antisemitic book "The Talmudic Jew" by German Catholic theologian August Rohling, a popular text with the anti-Jewish newspaper Der Stürmer in the years leading up to the Holocaust and the rise of the Third Reich. The book, which claims to lift passages from the Talmud has been utilized by antisemites like internet personality Candace Owens as justification for anti-Jewish bigotry, making ahistorical and conspiratorial claims about Jewish influence. See also References On individual tractates Historical study External links |
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[SOURCE: https://en.wikipedia.org/wiki/Animal#cite_note-Avila1995-13] | [TOKENS: 6011] |
Contents Animal Animals are multicellular, eukaryotic organisms belonging to the biological kingdom Animalia (/ˌænɪˈmeɪliə/). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor. Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft). They have complex ecologies and interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology, and the study of animal behaviour is known as ethology. The animal kingdom is divided into five major clades, namely Porifera, Ctenophora, Placozoa, Cnidaria and Bilateria. Most living animal species belong to the clade Bilateria, a highly proliferative clade whose members have a bilaterally symmetric and significantly cephalised body plan, and the vast majority of bilaterians belong to two large clades: the protostomes, which includes organisms such as arthropods, molluscs, flatworms, annelids and nematodes; and the deuterostomes, which include echinoderms, hemichordates and chordates, the latter of which contains the vertebrates. The much smaller basal phylum Xenacoelomorpha have an uncertain position within Bilateria. Animals first appeared in the fossil record in the late Cryogenian period and diversified in the subsequent Ediacaran period in what is known as the Avalon explosion. Nearly all modern animal phyla first appeared in the fossil record as marine species during the Cambrian explosion, which began around 539 million years ago (Mya), and most classes during the Ordovician radiation 485.4 Mya. Common to all living animals, 6,331 groups of genes have been identified that may have arisen from a single common ancestor that lived about 650 Mya during the Cryogenian period. Historically, Aristotle divided animals into those with blood and those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa (now synonymous with Animalia) and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between taxa. Humans make use of many other animal species for food (including meat, eggs, and dairy products), for materials (such as leather, fur, and wool), as pets and as working animals for transportation, and services. Dogs, the first domesticated animal, have been used in hunting, in security and in warfare, as have horses, pigeons and birds of prey; while other terrestrial and aquatic animals are hunted for sports, trophies or profits. Non-human animals are also an important cultural element of human evolution, having appeared in cave arts and totems since the earliest times, and are frequently featured in mythology, religion, arts, literature, heraldry, politics, and sports. Etymology The word animal comes from the Latin noun animal of the same meaning, which is itself derived from Latin animalis 'having breath or soul'. The biological definition includes all members of the kingdom Animalia. In colloquial usage, the term animal is often used to refer only to nonhuman animals. The term metazoa is derived from Ancient Greek μετα meta 'after' (in biology, the prefix meta- stands for 'later') and ζῷᾰ zōia 'animals', plural of ζῷον zōion 'animal'. A metazoan is any member of the group Metazoa. Characteristics Animals have several characteristics that they share with other living things. Animals are eukaryotic, multicellular, and aerobic, as are plants and fungi. Unlike plants and algae, which produce their own food, animals cannot produce their own food, a feature they share with fungi. Animals ingest organic material and digest it internally. Animals have structural characteristics that set them apart from all other living things: Typically, there is an internal digestive chamber with either one opening (in Ctenophora, Cnidaria, and flatworms) or two openings (in most bilaterians). Animal development is controlled by Hox genes, which signal the times and places to develop structures such as body segments and limbs. During development, the animal extracellular matrix forms a relatively flexible framework upon which cells can move about and be reorganised into specialised tissues and organs, making the formation of complex structures possible, and allowing cells to be differentiated. The extracellular matrix may be calcified, forming structures such as shells, bones, and spicules. In contrast, the cells of other multicellular organisms (primarily algae, plants, and fungi) are held in place by cell walls, and so develop by progressive growth. Nearly all animals make use of some form of sexual reproduction. They produce haploid gametes by meiosis; the smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova. These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm, also develops between them. These germ layers then differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction generally leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. Some animals are capable of asexual reproduction, which often results in a genetic clone of the parent. This may take place through fragmentation; budding, such as in Hydra and other cnidarians; or parthenogenesis, where fertile eggs are produced without mating, such as in aphids. Ecology Animals are categorised into ecological groups depending on their trophic levels and how they consume organic material. Such groupings include carnivores (further divided into subcategories such as piscivores, insectivores, ovivores, etc.), herbivores (subcategorised into folivores, graminivores, frugivores, granivores, nectarivores, algivores, etc.), omnivores, fungivores, scavengers/detritivores, and parasites. Interactions between animals of each biome form complex food webs within that ecosystem. In carnivorous or omnivorous species, predation is a consumer–resource interaction where the predator feeds on another organism, its prey, who often evolves anti-predator adaptations to avoid being fed upon. Selective pressures imposed on one another lead to an evolutionary arms race between predator and prey, resulting in various antagonistic/competitive coevolutions. Almost all multicellular predators are animals. Some consumers use multiple methods; for example, in parasitoid wasps, the larvae feed on the hosts' living tissues, killing them in the process, but the adults primarily consume nectar from flowers. Other animals may have very specific feeding behaviours, such as hawksbill sea turtles which mainly eat sponges. Most animals rely on biomass and bioenergy produced by plants and phytoplanktons (collectively called producers) through photosynthesis. Herbivores, as primary consumers, eat the plant material directly to digest and absorb the nutrients, while carnivores and other animals on higher trophic levels indirectly acquire the nutrients by eating the herbivores or other animals that have eaten the herbivores. Animals oxidise carbohydrates, lipids, proteins and other biomolecules in cellular respiration, which allows the animal to grow and to sustain basal metabolism and fuel other biological processes such as locomotion. Some benthic animals living close to hydrothermal vents and cold seeps on the dark sea floor consume organic matter produced through chemosynthesis (via oxidising inorganic compounds such as hydrogen sulfide) by archaea and bacteria. Animals originated in the ocean; all extant animal phyla, except for Micrognathozoa and Onychophora, feature at least some marine species. However, several lineages of arthropods begun to colonise land around the same time as land plants, probably between 510 and 471 million years ago, during the Late Cambrian or Early Ordovician. Vertebrates such as the lobe-finned fish Tiktaalik started to move on to land in the late Devonian, about 375 million years ago. Other notable animal groups that colonized land environments are Mollusca, Platyhelmintha, Annelida, Tardigrada, Onychophora, Rotifera, Nematoda. Animals occupy virtually all of earth's habitats and microhabitats, with faunas adapted to salt water, hydrothermal vents, fresh water, hot springs, swamps, forests, pastures, deserts, air, and the interiors of other organisms. Animals are however not particularly heat tolerant; very few of them can survive at constant temperatures above 50 °C (122 °F) or in the most extreme cold deserts of continental Antarctica. The collective global geomorphic influence of animals on the processes shaping the Earth's surface remains largely understudied, with most studies limited to individual species and well-known exemplars. Diversity The blue whale (Balaenoptera musculus) is the largest animal that has ever lived, weighing up to 190 tonnes and measuring up to 33.6 metres (110 ft) long. The largest extant terrestrial animal is the African bush elephant (Loxodonta africana), weighing up to 12.25 tonnes and measuring up to 10.67 metres (35.0 ft) long. The largest terrestrial animals that ever lived were titanosaur sauropod dinosaurs such as Argentinosaurus, which may have weighed as much as 73 tonnes, and Supersaurus which may have reached 39 metres. Several animals are microscopic; some Myxozoa (obligate parasites within the Cnidaria) never grow larger than 20 μm, and one of the smallest species (Myxobolus shekel) is no more than 8.5 μm when fully grown. The following table lists estimated numbers of described extant species for the major animal phyla, along with their principal habitats (terrestrial, fresh water, and marine), and free-living or parasitic ways of life. Species estimates shown here are based on numbers described scientifically; much larger estimates have been calculated based on various means of prediction, and these can vary wildly. For instance, around 25,000–27,000 species of nematodes have been described, while published estimates of the total number of nematode species include 10,000–20,000; 500,000; 10 million; and 100 million. Using patterns within the taxonomic hierarchy, the total number of animal species—including those not yet described—was calculated to be about 7.77 million in 2011.[a] 3,000–6,500 4,000–25,000 Evolutionary origin Evidence of animals is found as long ago as the Cryogenian period. 24-Isopropylcholestane (24-ipc) has been found in rocks from roughly 650 million years ago; it is only produced by sponges and pelagophyte algae. Its likely origin is from sponges based on molecular clock estimates for the origin of 24-ipc production in both groups. Analyses of pelagophyte algae consistently recover a Phanerozoic origin, while analyses of sponges recover a Neoproterozoic origin, consistent with the appearance of 24-ipc in the fossil record. The first body fossils of animals appear in the Ediacaran, represented by forms such as Charnia and Spriggina. It had long been doubted whether these fossils truly represented animals, but the discovery of the animal lipid cholesterol in fossils of Dickinsonia establishes their nature. Animals are thought to have originated under low-oxygen conditions, suggesting that they were capable of living entirely by anaerobic respiration, but as they became specialised for aerobic metabolism they became fully dependent on oxygen in their environments. Many animal phyla first appear in the fossil record during the Cambrian explosion, starting about 539 million years ago, in beds such as the Burgess Shale. Extant phyla in these rocks include molluscs, brachiopods, onychophorans, tardigrades, arthropods, echinoderms and hemichordates, along with numerous now-extinct forms such as the predatory Anomalocaris. The apparent suddenness of the event may however be an artefact of the fossil record, rather than showing that all these animals appeared simultaneously. That view is supported by the discovery of Auroralumina attenboroughii, the earliest known Ediacaran crown-group cnidarian (557–562 mya, some 20 million years before the Cambrian explosion) from Charnwood Forest, England. It is thought to be one of the earliest predators, catching small prey with its nematocysts as modern cnidarians do. Some palaeontologists have suggested that animals appeared much earlier than the Cambrian explosion, possibly as early as 1 billion years ago. Early fossils that might represent animals appear for example in the 665-million-year-old rocks of the Trezona Formation of South Australia. These fossils are interpreted as most probably being early sponges. Trace fossils such as tracks and burrows found in the Tonian period (from 1 gya) may indicate the presence of triploblastic worm-like animals, roughly as large (about 5 mm wide) and complex as earthworms. However, similar tracks are produced by the giant single-celled protist Gromia sphaerica, so the Tonian trace fossils may not indicate early animal evolution. Around the same time, the layered mats of microorganisms called stromatolites decreased in diversity, perhaps due to grazing by newly evolved animals. Objects such as sediment-filled tubes that resemble trace fossils of the burrows of wormlike animals have been found in 1.2 gya rocks in North America, in 1.5 gya rocks in Australia and North America, and in 1.7 gya rocks in Australia. Their interpretation as having an animal origin is disputed, as they might be water-escape or other structures. Phylogeny Animals are monophyletic, meaning they are derived from a common ancestor. Animals are the sister group to the choanoflagellates, with which they form the Choanozoa. Ros-Rocher and colleagues (2021) trace the origins of animals to unicellular ancestors, providing the external phylogeny shown in the cladogram. Uncertainty of relationships is indicated with dashed lines. The animal clade had certainly originated by 650 mya, and may have come into being as much as 800 mya, based on molecular clock evidence for different phyla. Holomycota (inc. fungi) Ichthyosporea Pluriformea Filasterea The relationships at the base of the animal tree have been debated. Other than Ctenophora, the Bilateria and Cnidaria are the only groups with symmetry, and other evidence shows they are closely related. In addition to sponges, Placozoa has no symmetry and was often considered a "missing link" between protists and multicellular animals. The presence of hox genes in Placozoa shows that they were once more complex. The Porifera (sponges) have long been assumed to be sister to the rest of the animals, but there is evidence that the Ctenophora may be in that position. Molecular phylogenetics has supported both the sponge-sister and ctenophore-sister hypotheses. In 2017, Roberto Feuda and colleagues, using amino acid differences, presented both, with the following cladogram for the sponge-sister view that they supported (their ctenophore-sister tree simply interchanging the places of ctenophores and sponges): Porifera Ctenophora Placozoa Cnidaria Bilateria Conversely, a 2023 study by Darrin Schultz and colleagues uses ancient gene linkages to construct the following ctenophore-sister phylogeny: Ctenophora Porifera Placozoa Cnidaria Bilateria Sponges are physically very distinct from other animals, and were long thought to have diverged first, representing the oldest animal phylum and forming a sister clade to all other animals. Despite their morphological dissimilarity with all other animals, genetic evidence suggests sponges may be more closely related to other animals than the comb jellies are. Sponges lack the complex organisation found in most other animal phyla; their cells are differentiated, but in most cases not organised into distinct tissues, unlike all other animals. They typically feed by drawing in water through pores, filtering out small particles of food. The Ctenophora and Cnidaria are radially symmetric and have digestive chambers with a single opening, which serves as both mouth and anus. Animals in both phyla have distinct tissues, but these are not organised into discrete organs. They are diploblastic, having only two main germ layers, ectoderm and endoderm. The tiny placozoans have no permanent digestive chamber and no symmetry; they superficially resemble amoebae. Their phylogeny is poorly defined, and under active research. The remaining animals, the great majority—comprising some 29 phyla and over a million species—form the Bilateria clade, which have a bilaterally symmetric body plan. The Bilateria are triploblastic, with three well-developed germ layers, and their tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and in the Nephrozoa there is an internal body cavity, a coelom or pseudocoelom. These animals have a head end (anterior) and a tail end (posterior), a back (dorsal) surface and a belly (ventral) surface, and a left and a right side. A modern consensus phylogenetic tree for the Bilateria is shown below. Xenacoelomorpha Ambulacraria Chordata Ecdysozoa Spiralia Having a front end means that this part of the body encounters stimuli, such as food, favouring cephalisation, the development of a head with sense organs and a mouth. Many bilaterians have a combination of circular muscles that constrict the body, making it longer, and an opposing set of longitudinal muscles, that shorten the body; these enable soft-bodied animals with a hydrostatic skeleton to move by peristalsis. They also have a gut that extends through the basically cylindrical body from mouth to anus. Many bilaterian phyla have primary larvae which swim with cilia and have an apical organ containing sensory cells. However, over evolutionary time, descendant spaces have evolved which have lost one or more of each of these characteristics. For example, adult echinoderms are radially symmetric (unlike their larvae), while some parasitic worms have extremely simplified body structures. Genetic studies have considerably changed zoologists' understanding of the relationships within the Bilateria. Most appear to belong to two major lineages, the protostomes and the deuterostomes. It is often suggested that the basalmost bilaterians are the Xenacoelomorpha, with all other bilaterians belonging to the subclade Nephrozoa. However, this suggestion has been contested, with other studies finding that xenacoelomorphs are more closely related to Ambulacraria than to other bilaterians. Protostomes and deuterostomes differ in several ways. Early in development, deuterostome embryos undergo radial cleavage during cell division, while many protostomes (the Spiralia) undergo spiral cleavage. Animals from both groups possess a complete digestive tract, but in protostomes the first opening of the embryonic gut develops into the mouth, and the anus forms secondarily. In deuterostomes, the anus forms first while the mouth develops secondarily. Most protostomes have schizocoelous development, where cells simply fill in the interior of the gastrula to form the mesoderm. In deuterostomes, the mesoderm forms by enterocoelic pouching, through invagination of the endoderm. The main deuterostome taxa are the Ambulacraria and the Chordata. Ambulacraria are exclusively marine and include acorn worms, starfish, sea urchins, and sea cucumbers. The chordates are dominated by the vertebrates (animals with backbones), which consist of fishes, amphibians, reptiles, birds, and mammals. The protostomes include the Ecdysozoa, named after their shared trait of ecdysis, growth by moulting, Among the largest ecdysozoan phyla are the arthropods and the nematodes. The rest of the protostomes are in the Spiralia, named for their pattern of developing by spiral cleavage in the early embryo. Major spiralian phyla include the annelids and molluscs. History of classification In the classical era, Aristotle divided animals,[d] based on his own observations, into those with blood (roughly, the vertebrates) and those without. The animals were then arranged on a scale from man (with blood, two legs, rational soul) down through the live-bearing tetrapods (with blood, four legs, sensitive soul) and other groups such as crustaceans (no blood, many legs, sensitive soul) down to spontaneously generating creatures like sponges (no blood, no legs, vegetable soul). Aristotle was uncertain whether sponges were animals, which in his system ought to have sensation, appetite, and locomotion, or plants, which did not: he knew that sponges could sense touch and would contract if about to be pulled off their rocks, but that they were rooted like plants and never moved about. In 1758, Carl Linnaeus created the first hierarchical classification in his Systema Naturae. In his original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then, the last four have all been subsumed into a single phylum, the Chordata, while his Insecta (which included the crustaceans and arachnids) and Vermes have been renamed or broken up. The process was begun in 1793 by Jean-Baptiste de Lamarck, who called the Vermes une espèce de chaos ('a chaotic mess')[e] and split the group into three new phyla: worms, echinoderms, and polyps (which contained corals and jellyfish). By 1809, in his Philosophie Zoologique, Lamarck had created nine phyla apart from vertebrates (where he still had four phyla: mammals, birds, reptiles, and fish) and molluscs, namely cirripedes, annelids, crustaceans, arachnids, insects, worms, radiates, polyps, and infusorians. In his 1817 Le Règne Animal, Georges Cuvier used comparative anatomy to group the animals into four embranchements ('branches' with different body plans, roughly corresponding to phyla), namely vertebrates, molluscs, articulated animals (arthropods and annelids), and zoophytes (radiata) (echinoderms, cnidaria and other forms). This division into four was followed by the embryologist Karl Ernst von Baer in 1828, the zoologist Louis Agassiz in 1857, and the comparative anatomist Richard Owen in 1860. In 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms: Metazoa (multicellular animals, with five phyla: coelenterates, echinoderms, articulates, molluscs, and vertebrates) and Protozoa (single-celled animals), including a sixth animal phylum, sponges. The protozoa were later moved to the former kingdom Protista, leaving only the Metazoa as a synonym of Animalia. In human culture The human population exploits a large number of other animal species for food, both of domesticated livestock species in animal husbandry and, mainly at sea, by hunting wild species. Marine fish of many species are caught commercially for food. A smaller number of species are farmed commercially. Humans and their livestock make up more than 90% of the biomass of all terrestrial vertebrates, and almost as much as all insects combined. Invertebrates including cephalopods, crustaceans, insects—principally bees and silkworms—and bivalve or gastropod molluscs are hunted or farmed for food, fibres. Chickens, cattle, sheep, pigs, and other animals are raised as livestock for meat across the world. Animal fibres such as wool and silk are used to make textiles, while animal sinews have been used as lashings and bindings, and leather is widely used to make shoes and other items. Animals have been hunted and farmed for their fur to make items such as coats and hats. Dyestuffs including carmine (cochineal), shellac, and kermes have been made from the bodies of insects. Working animals including cattle and horses have been used for work and transport from the first days of agriculture. Animals such as the fruit fly Drosophila melanogaster serve a major role in science as experimental models. Animals have been used to create vaccines since their discovery in the 18th century. Some medicines such as the cancer drug trabectedin are based on toxins or other molecules of animal origin. People have used hunting dogs to help chase down and retrieve animals, and birds of prey to catch birds and mammals, while tethered cormorants have been used to catch fish. Poison dart frogs have been used to poison the tips of blowpipe darts. A wide variety of animals are kept as pets, from invertebrates such as tarantulas, octopuses, and praying mantises, reptiles such as snakes and chameleons, and birds including canaries, parakeets, and parrots all finding a place. However, the most kept pet species are mammals, namely dogs, cats, and rabbits. There is a tension between the role of animals as companions to humans, and their existence as individuals with rights of their own. A wide variety of terrestrial and aquatic animals are hunted for sport. The signs of the Western and Chinese zodiacs are based on animals. In China and Japan, the butterfly has been seen as the personification of a person's soul, and in classical representation the butterfly is also the symbol of the soul. Animals have been the subjects of art from the earliest times, both historical, as in ancient Egypt, and prehistoric, as in the cave paintings at Lascaux. Major animal paintings include Albrecht Dürer's 1515 The Rhinoceros, and George Stubbs's c. 1762 horse portrait Whistlejacket. Insects, birds and mammals play roles in literature and film, such as in giant bug movies. Animals including insects and mammals feature in mythology and religion. The scarab beetle was sacred in ancient Egypt, and the cow is sacred in Hinduism. Among other mammals, deer, horses, lions, bats, bears, and wolves are the subjects of myths and worship. See also Notes References External links |
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[SOURCE: https://he.wikipedia.org/wiki/ויקישיתוף] | [TOKENS: 3951] |
תוכן עניינים ויקישיתוף ויקישיתוף (באנגלית: Wikimedia Commons) הוא מאגר של תמונות, צלילים וקובצי מולטימדיה אחרים חופשיים. זהו מיזם השייך לקרן ויקימדיה, והקבצים שהועלו לאתר זה יכולים לשמש את כל מיזמי קרן ויקימדיה בכל השפות. לחלופין, אפשר להשתמש בהם גם מחוץ לאתר זה, בהתאם לרישיון התוכן שמשתמשים בו (רשות הציבור או ברישיון חופשי אחר, כמו הרישיון לשימוש חופשי במסמכים של גנו). בדצמבר 2023 מספר הקבצים החופשיים במאגר היה מעל 100 מיליון. היסטוריה מיזם זה הוצע על ידי אריק מולר (Erik Möller) ב-19 במרץ 2004, ונפתח ב-7 בספטמבר באותה שנה. המטרה העיקרית ליצירת מאגר כללי הייתה הרצון לצמצום שכפולי יצירות בין מיזמי ושפות ויקימדיה, שבשמם הדומה הועלו למיזמי ויקי שונים לפני שוויקישיתוף נוצר. האפשרות הטכנית לשימוש בכל הקבצים מוויקישיתוף בכל מיזמי ויקימדיה יושמה ואופשרה באוקטובר 2004, ובכל אתר ויקימדיה מאז יש אימוץ מהיר של ויקישיתוף כמחסן. לוגו המיזם הוכן על ידי רייד בילס, ששלח אותו בהתחלה לתחרות הלוגואים של ויקיחדשות. התמונה הוכנסה לתוך תחרות הלוגואים של ויקישיתוף, שם ניצחה, ואומצה באופן רשמי בנובמבר 2004. במהלך חודש אפריל בשנת 2005, חברה מברלין בשם "Directmedia Publishing", הוציאה לאור מהדורה של ויקיפדיה בגרמנית ב-DVD, ונתרמו משם 10,000 עותקים של איורים ברשות הציבור, שהועלו עם המידע על התמונה ועל יוצריה. מספר הקבצים בוויקישיתוף הגיע ל-100,000 ב-24 במאי 2005 (ללא אלפי תמונות של מזג האוויר או של מידע שוק לוויקיחדשות). הוא גם קיבל אזכור של כבוד בפרסי "Prix Ars Electronica" במאי 2005. ויקישיתוף השיגו את הקובץ המיליון ב-30 בנובמבר 2006. תמונת הפסיפס של לוגו קרן ויקימדיה הוכן ידנית על ידי עורכי האתר, כדי לחגוג את ציון הדרך. לאחר מכן, פותחו כלים לממשק בין ויקישיתוף לשאר אתרי קרן ויקימדיה. דניאל קִּינְזְלֶר כתב יישומים למציאת קטגוריות מתאימות לקבצים שהועלו ("CommonSense"), בדיקת שימוש בקובצי ויקישיתוף בשאר אתרי ויקימדיה ("CheckUsage"), איתור תמונות עם חוסר מידע על זכויות יוצרים, ומסירת מידע אודות פעולות ניהוליות כגון מחיקות באתרי ויקי רלוונטיים. לאתר גם יש עוד מנוע חיפוש לתמונות הקרוי בשם "MayFlower". כלים וסקריפטים של העלאות מיוחדות, כמו ה-"commonist", נוצרו לפשט את תהליך ההעלאה של מספר רב של קבצים. בהוראה לסקור תצלומים חופשיים שהועלו לפליקר, משתמשים יכולים לשתף פעולה בהעלאת תמונות משם דרך תהליך חיצוני ("FlickrLickr"), משם הועלו יותר מ-10,000 קבצים לוויקישיתוף. מדיניות ושימוש רוב מיזמי ויקימדיה עדיין מאפשרים העלאות מקומיות שלא יופיעו במיזמים אחרים או בשפות אחרות, אבל אפשרות זו מכוונת לשימוש ברישיונות שהמיזם המקומי מאפשר, אך ללא היתר לשיתוף בתכני זכויות יוצרים, כמו תוכן בשימוש הוגן. ויקישיתוף בעצמו אינו מאפשר העלאות בשימוש הוגן, העלאות שלא ברישיונות חופשיים, הכללת רישיונות המגבילים שימוש מסחרי ועבודות מועתקות. הרישיונות שמקובל לכלול הם הרישיון לשימוש חופשי במסמכים של גנו, רישיונות ייחוס ושיתוף זהה של Creative Commons ואת רשות הציבור. שפת ברירת המחדל בוויקישיתוף היא אנגלית, אך משתמשים רשומים יכולים להתאים באופן אישי את ממשק המשתמש שלהם כך שישתמש בכל שפה אחרת. להרבה דפי תוכן (דפים ספציפיים ופורטלים), ישנו תרגום למגוון שפות. קבצים בוויקישיתוף מסווגים בשיטת הקטגוריות של מדיה ויקי. בנוסף, הם לעיתים קרובות מסווגים בדפי גלריה. על אף שמלכתחילה הוצע שהמיזם יכלול גם קובצי טקסט חופשיים, קובצי הטקסט אורחו במיזם אחות של ויקישיתוף – ויקיטקסט. איכות לוויקישיתוף ישנם שני מנגנונים להכרה בעבודות איכותיות. האחד ידוע בשם "תמונות מומלצות" (Featured pictures), שם מוגשות למעמד זה תמונות, וקהילת חברי ויקישיתוף מצביעים האם לקבל או לדחות את המועמדויות. תהליך זה החל בנובמבר 2004. המנגנון השני ידוע בשם "תמונות איכותיות" (Quality images), אשר נפתח ביוני 2006, ותהליך הגשת המועמדויות אליו פשוטות יותר מב"תמונות המומלצות". ל"תמונות האיכותיות" מתקבלות רק עבודות שנוצרו באמצעות משתמשי ויקימדיה, בעוד של"תמונות המומלצות" מתקבלות בנוסף מועמדויות של עבודות שנוצרו על ידי גוף שלישי, כמו נאס"א. תמונות האיכות נבחנות באיכותן הטכנית, ברזולוציה גבוהה, בחשיפה נכונה, בחדות ובקומפוזציה. מיזם הערכת תמונות נוסף, ידוע בשם "תמונות מוערכות" (Valued images) שנפתח ב-1 ביוני 2008 במטרה להכיר באיור המוערך ביותר מסוגו. בניגוד לשני התהליכים האחרים, כל תמונה מוערכת בעיקר לפי המידה בה היא תורמת וממחישה את הנושא אותו היא מתארת והאם היא הטובה ביותר בהמחשת נושא זה. "תמונת השנה" בוויקישיתוף מוכרזת בכל שנה החל מינואר 2007. התמונות הטובות ביותר, מבין אלו שלהן רישיון חופשי וזכו לתג "תמונה מומלצת" במהלך השנה החולפת, מועמדות לתחרות. המשתמשים הפעילים במיזמי ויקימדיה בוחרים את תמונות השנה בשני סבבי הצבעה. ראו גם קישורים חיצוניים הערות שוליים גילוי נאות: ערך זה מזכיר את קרן ויקימדיה או את אחד המיזמים שלה. ויקיפדיה היא מיזם של קרן ויקימדיה. |
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[SOURCE: https://en.wikipedia.org/wiki/Fungi] | [TOKENS: 13939] |
Contents Fungus A fungus (pl.: fungi[e] or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified in the kingdom Fungi. A characteristic that places Fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved organic molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the Eumycota (true fungi or Eumycetes), that share a common ancestor (i.e. they form a monophyletic group), an interpretation that is also strongly supported by molecular phylogenetics. This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). The discipline of biology devoted to the study of fungi is known as mycology (from the Greek μύκης, mykes 'mushroom'). In the past, mycology was regarded as a branch of botany, although it is now known that fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungi include symbionts of plants, animals, or other fungi and also parasites. They may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. Over 90% of plants are dependent on Mycorrhizal symbiosis between plants and fungi and this process also enhances photosynthesis in plants, increasing carbon uptake from the atmosphere and helping to stop climate change. They have long been used as a direct source of human food, in the form of mushrooms and truffles; as a leavening agent for bread; and in the fermentation of various food products, such as wine, beer, and soy sauce. Since the 1940s, fungi have been used for the production of antibiotics, and, more recently, various enzymes produced by fungi are used industrially and in detergents. Fungi are also used as biological pesticides to control weeds, plant diseases, and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, that are toxic to animals, including humans. The fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Losses of crops due to fungal diseases (e.g., rice blast disease) or food spoilage can have a large impact on human food supplies and local economies. Fungi are threatened by fungicides, pesticides, pollution, deforestation and more. The fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from unicellular aquatic chytrids to large mushrooms. However, little is known of the true biodiversity of the fungus kingdom, which has been estimated at 2.2 million to 3.8 million species. Of these, only about 148,000 have been described, with over 8,000 species known to be detrimental to plants and at least 300 that can be pathogenic to humans. Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus, Christiaan Hendrik Persoon, and Elias Magnus Fries, fungi have been classified according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Phylogenetic studies published in the first decade of the 21st century have helped reshape the classification within the fungi kingdom, which is divided into one subkingdom, seven phyla, and ten subphyla. Etymology The English word fungus is directly adopted from the Latin fungus 'mushroom', used in the writings of Horace and Pliny. This in turn is derived from the Greek word sphongos (σφόγγος 'sponge'), which refers to the macroscopic structures and morphology of mushrooms and molds; the root is also used in other languages, such as the German Schwamm 'sponge' and Schimmel 'mold'. The word mycology is derived from the Greek mykes (μύκης 'mushroom') and logos (λόγος 'discourse'). It denotes the scientific study of fungi. The Latin adjectival form of "mycology" (mycologicæ) appeared as early as 1796 in a book on the subject by Christiaan Hendrik Persoon. The word appeared in English as early as 1824 in a book by Robert Kaye Greville. In 1836 the English naturalist Miles Joseph Berkeley's publication The English Flora of Sir James Edward Smith, Vol. 5. also refers to mycology as the study of fungi. A group of all the fungi present in a particular region is known as mycobiota (plural noun, no singular). The term mycota is often used for this purpose, but many authors use it as a synonym of Fungi. The word funga has been proposed as a less ambiguous term morphologically similar to fauna and flora. The Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN) in August 2021 asked that the phrase fauna and flora be replaced by fauna, flora, and funga. Characteristics Before the introduction of molecular methods for phylogenetic analysis, taxonomists considered fungi to be members of the plant kingdom because of similarities in lifestyle: both fungi and plants are mainly immobile, and have similarities in general morphology and growth habit. Although inaccurate, the common misconception that fungi are plants persists among the general public due to their historical classification, as well as several similarities. Like plants, fungi often grow in soil and, in the case of mushrooms, form conspicuous fruit bodies, which sometimes resemble plants such as mosses. The fungi are now considered a separate kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago (around the start of the Neoproterozoic Era). Some morphological, biochemical, and genetic features are shared with other organisms, while others are unique to the fungi, clearly separating them from the other kingdoms: Shared features: Unique features: Most fungi lack an efficient system for the long-distance transport of water and nutrients, such as the xylem and phloem in many plants. To overcome this limitation, some fungi, such as Armillaria, form rhizomorphs, which resemble and perform functions similar to the roots of plants. As eukaryotes, fungi possess a biosynthetic pathway for producing terpenes that uses mevalonic acid and pyrophosphate as chemical building blocks. Plants and some other organisms have an additional terpene biosynthesis pathway in their chloroplasts, a structure that fungi and animals do not have. Fungi produce several secondary metabolites that are similar or identical in structure to those made by plants. Many of the plant and fungal enzymes that make these compounds differ from each other in sequence and other characteristics, which indicates separate origins and convergent evolution of these enzymes in the fungi and plants. Diversity Fungi have a worldwide distribution, and grow in a wide range of habitats, including extreme environments such as deserts or areas with high salt concentrations or ionizing radiation, as well as in deep sea sediments. Some can survive the intense UV and cosmic radiation encountered during space travel. Most grow in terrestrial environments, though several species live partly or solely in aquatic habitats, such as the chytrid fungi Batrachochytrium dendrobatidis and B. salamandrivorans, parasites that have been responsible for a worldwide decline in amphibian populations. These organisms spend part of their life cycle as a motile zoospore, enabling them to propel themselves through water and enter their amphibian host. Other examples of aquatic fungi include those living in hydrothermal areas of the ocean. As of 2020,[update] around 148,000 species of fungi have been described by taxonomists, but the global biodiversity of the fungus kingdom is not fully understood. A 2017 estimate suggests there may be between 2.2 and 3.8 million species. The number of new fungi species discovered yearly has increased from 1,000 to 1,500 per year about 10 years ago, to about 2,000 with a peak of more than 2,500 species in 2016. In the year 2019, 1,882 new species of fungi were described, and it was estimated that more than 90% of fungi remain unknown. The following year, 2,905 new species were described—the highest annual record of new fungus names. In mycology, species have historically been distinguished by a variety of methods and concepts. Classification based on morphological characteristics, such as the size and shape of spores or fruiting structures, has traditionally dominated fungal taxonomy. Species may also be distinguished by their biochemical and physiological characteristics, such as their ability to metabolize certain biochemicals, or their reaction to chemical tests. The biological species concept discriminates species based on their ability to mate. The application of molecular tools, such as DNA sequencing and phylogenetic analysis, to study diversity has greatly enhanced the resolution and added robustness to estimates of genetic diversity within various taxonomic groups. Mycology Mycology is the branch of biology concerned with the systematic study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source of medicine, food, and psychotropic substances consumed for religious purposes, as well as their dangers, such as poisoning or infection. The field of phytopathology, the study of plant diseases, is closely related because many plant pathogens are fungi. The use of fungi by humans dates back to prehistory; Ötzi the Iceman, a well-preserved mummy of a 5,300-year-old Neolithic man found frozen in the Austrian Alps, carried two species of polypore mushrooms that may have been used as tinder (Fomes fomentarius), or for medicinal purposes (Piptoporus betulinus). Ancient peoples have used fungi as food sources—often unknowingly—for millennia, in the preparation of leavened bread and fermented juices. Some of the oldest written records contain references to crop destruction that was probably caused by pathogenic fungi. Mycology became a systematic science after the development of the microscope in the 17th century. Although fungal spores were first observed by Giambattista della Porta in 1588, the seminal work in the development of mycology is considered to be the publication of Pier Antonio Micheli's 1729 work Nova plantarum genera. Micheli not only observed spores but also showed that, under the proper conditions, they could be induced into growing into the same species of fungi from which they originated. Extending the use of the binomial system of nomenclature introduced by Carl Linnaeus in his Species plantarum (1753), the Dutch Christiaan Hendrik Persoon (1761–1836) established the first classification of mushrooms with such skill as to be considered a founder of modern mycology. Later, Elias Magnus Fries (1794–1878) further elaborated the classification of fungi, using spore color and microscopic characteristics, methods still used by taxonomists today. Other notable early contributors to mycology in the 17th–19th and early 20th centuries include Miles Joseph Berkeley, August Carl Joseph Corda, Anton de Bary, the brothers Louis René and Charles Tulasne, Arthur H. R. Buller, Curtis G. Lloyd, and Pier Andrea Saccardo. In the 20th and 21st centuries, advances in biochemistry, genetics, molecular biology, biotechnology, DNA sequencing, and phylogenetic analysis have provided new insights into fungal relationships and biodiversity, and have challenged traditional morphology-based groupings in fungal taxonomy. Morphology Most fungi grow as hyphae, which are cylindrical, thread-like structures 2–10 μm in diameter and up to several centimeters in length. Hyphae grow at their tips (apices); new hyphae are typically formed by emergence of new tips along existing hyphae by a process called branching, or occasionally growing hyphal tips fork, giving rise to two parallel-growing hyphae. Hyphae also sometimes fuse when they come into contact, a process called hyphal fusion (or anastomosis). These growth processes lead to the development of a mycelium, an interconnected network of hyphae. Hyphae can be either septate or coenocytic. Septate hyphae are divided into compartments separated by cross walls (internal cell walls, called septa, that are formed at right angles to the cell wall giving the hypha its shape), with each compartment containing one or more nuclei; coenocytic hyphae are not compartmentalized. Septa have pores that allow cytoplasm, organelles, and sometimes nuclei to pass through; an example is the dolipore septum in fungi of the phylum Basidiomycota. Coenocytic hyphae are in essence multinucleate supercells. Many species have developed specialized hyphal structures for nutrient uptake from living hosts; examples include haustoria in plant-parasitic species of most fungal phyla, and arbuscules of several mycorrhizal fungi, which penetrate into the host cells to consume nutrients. Although fungi are opisthokonts—a grouping of evolutionarily related organisms broadly characterized by a single posterior flagellum—all phyla except for the chytrids and blastocladiomycetes have lost their posterior flagella. Fungi are unusual among the eukaryotes in having a cell wall that, in addition to glucans (e.g., β-1,3-glucan) and other typical components, also contains the biopolymer chitin. Fungal mycelia can become visible to the naked eye, for example, on various surfaces and substrates, such as damp walls and spoiled food, where they are commonly called molds. Mycelia grown on solid agar media in laboratory petri dishes are usually referred to as colonies. These colonies can exhibit growth shapes and colors (due to spores or pigmentation) that can be used as diagnostic features in the identification of species or groups. Some individual fungal colonies can reach extraordinary dimensions and ages as in the case of a clonal colony of Armillaria solidipes, which extends over an area of more than 900 ha (3.5 square miles), with an estimated age of nearly 9,000 years. The apothecium—a specialized structure important in sexual reproduction in the ascomycetes—is a cup-shaped fruit body that is often macroscopic and holds the hymenium, a layer of tissue containing the spore-bearing cells. The fruit bodies of the basidiomycetes (basidiocarps) and some ascomycetes can sometimes grow very large, and many are well known as mushrooms. Growth and physiology The growth of fungi as hyphae on or in solid substrates or as single cells in aquatic environments is adapted for the efficient extraction of nutrients, because these growth forms have high surface area to volume ratios. Hyphae are specifically adapted for growth on solid surfaces, and to invade substrates and tissues. They can exert large penetrative mechanical forces; for example, many plant pathogens, including Magnaporthe grisea, form a structure called an appressorium that evolved to puncture plant tissues. The pressure generated by the appressorium, directed against the plant epidermis, can exceed 8 megapascals (1,200 psi). The filamentous fungus Purpureocillium lilacinum uses a similar structure to penetrate the eggs of nematodes. The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular turgor by producing osmolytes such as glycerol. Adaptations such as these are complemented by hydrolytic enzymes secreted into the environment to digest large organic molecules—such as polysaccharides, proteins, and lipids—into smaller molecules that may then be absorbed as nutrients. The vast majority of filamentous fungi grow in a polar fashion (extending in one direction) by elongation at the tip (apex) of the hypha. Other forms of fungal growth include intercalary extension (longitudinal expansion of hyphal compartments that are below the apex) as in the case of some endophytic fungi, or growth by volume expansion during the development of mushroom stipes and other large organs. Growth of fungi as multicellular structures consisting of somatic and reproductive cells—a feature independently evolved in animals and plants—has several functions, including the development of fruit bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication. Fungi are traditionally considered heterotrophs, organisms that rely solely on carbon fixed by other organisms for metabolism. Fungi have evolved a high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate, ammonia, acetate, or ethanol. In some species the pigment melanin may play a role in extracting energy from ionizing radiation, such as gamma radiation. This form of "radiotrophic" growth has been described for only a few species, the effects on growth rates are small, and the underlying biophysical and biochemical processes are not well known. This process might bear similarity to CO2 fixation via visible light, but instead uses ionizing radiation as a source of energy. Reproduction Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms. It is estimated that a third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph (sexual reproduction stage) and the anamorph (asexual reproduction stage). Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules. Asexual reproduction occurs via vegetative spores (conidia) or through mycelial fragmentation. Mycelial fragmentation occurs when a fungal mycelium separates into pieces, and each component grows into a separate mycelium. Mycelial fragmentation and vegetative spores maintain clonal populations adapted to a specific niche, and allow more rapid dispersal than sexual reproduction. The Fungi imperfecti ('fungi lacking the perfect or sexual stage') or Deuteromycota comprise all the species that lack an observable sexual cycle. Deuteromycota (alternatively known as Deuteromycetes, conidial fungi, or mitosporic fungi) is not an accepted taxonomic clade and is now taken to mean simply fungi that lack a known sexual stage. Sexual reproduction with meiosis has been directly observed in all fungal phyla except Glomeromycota (genetic analysis suggests meiosis in Glomeromycota as well). It differs in many aspects from sexual reproduction in animals or plants. Differences also exist between fungal groups and can be used to discriminate species by morphological differences in sexual structures and reproductive strategies. Mating experiments between fungal isolates may identify species on the basis of biological species concepts. The major fungal groupings have initially been delineated based on the morphology of their sexual structures and spores; for example, the spore-containing structures, asci and basidia, can be used in the identification of ascomycetes and basidiomycetes, respectively. Fungi employ two mating systems: heterothallic species allow mating only between individuals of the opposite mating type, whereas homothallic species can mate, and sexually reproduce, with any other individual or itself. Most fungi have both a haploid and a diploid stage in their life cycles. In sexually reproducing fungi, compatible individuals may combine by fusing their hyphae together into an interconnected network; this process, anastomosis, is required for the initiation of the sexual cycle. Many ascomycetes and basidiomycetes go through a dikaryotic stage, in which the nuclei inherited from the two parents do not combine immediately after cell fusion, but remain separate in the hyphal cells (see heterokaryosis). In ascomycetes, dikaryotic hyphae of the hymenium (the spore-bearing tissue layer) form a characteristic hook (crozier) at the hyphal septum. During cell division, the formation of the hook ensures proper distribution of the newly divided nuclei into the apical and basal hyphal compartments. An ascus (plural asci) is then formed, in which karyogamy (nuclear fusion) occurs. Asci are embedded in an ascocarp, or fruiting body. Karyogamy in the asci is followed immediately by meiosis and the production of ascospores. After dispersal, the ascospores may germinate and form a new haploid mycelium. Sexual reproduction in basidiomycetes is similar to that of the ascomycetes. Compatible haploid hyphae fuse to produce a dikaryotic mycelium. However, the dikaryotic phase is more extensive in the basidiomycetes, often also present in the vegetatively growing mycelium. A specialized anatomical structure, called a clamp connection, is formed at each hyphal septum. As with the structurally similar hook in the ascomycetes, the clamp connection in the basidiomycetes is required for controlled transfer of nuclei during cell division, to maintain the dikaryotic stage with two genetically different nuclei in each hyphal compartment. A basidiocarp is formed in which club-like structures known as basidia generate haploid basidiospores after karyogamy and meiosis. The most commonly known basidiocarps are mushrooms, but they may also take other forms (see Morphology section). In fungi formerly classified as Zygomycota, haploid hyphae of two individuals fuse, forming a gametangium, a specialized cell structure that becomes a fertile gamete-producing cell. The gametangium develops into a zygospore, a thick-walled spore formed by the union of gametes. When the zygospore germinates, it undergoes meiosis, generating new haploid hyphae, which may then form asexual sporangiospores. These sporangiospores allow the fungus to rapidly disperse and germinate into new genetically identical haploid fungal mycelia. The spores of most of the researched species of fungi are transported by wind. Such species often produce dry or hydrophobic spores that do not absorb water and are readily scattered by raindrops, for example. In other species, both asexual and sexual spores or sporangiospores are often actively dispersed by forcible ejection from their reproductive structures. This ejection ensures exit of the spores from the reproductive structures as well as traveling through the air over long distances. Specialized mechanical and physiological mechanisms, as well as spore surface structures (such as hydrophobins), enable efficient spore ejection. For example, the structure of the spore-bearing cells in some ascomycete species is such that the buildup of substances affecting cell volume and fluid balance enables the explosive discharge of spores into the air. The forcible discharge of single spores termed ballistospores involves formation of a small drop of water (Buller's drop), which upon contact with the spore leads to its projectile release with an initial acceleration of more than 10,000 g; the net result is that the spore is ejected 0.01–0.02 cm, sufficient distance for it to fall through the gills or pores into the air below. Other fungi, like the puffballs, rely on alternative mechanisms for spore release, such as external mechanical forces. The hydnoid fungi (tooth fungi) produce spores on pendant, tooth-like or spine-like projections. The bird's nest fungi use the force of falling water drops to liberate the spores from cup-shaped fruiting bodies. Another strategy is seen in the stinkhorns, a group of fungi with lively colors and putrid odor that attract insects to disperse their spores. In homothallic sexual reproduction, two haploid nuclei derived from the same individual fuse to form a zygote that can then undergo meiosis. Homothallic fungi include species with an Aspergillus-like asexual stage (anamorphs) occurring in numerous different genera, several species of the ascomycete genus Cochliobolus, and the ascomycete Pneumocystis jirovecii. The earliest mode of sexual reproduction among eukaryotes was likely homothallism, that is, self-fertile unisexual reproduction. Besides regular sexual reproduction with meiosis, certain fungi, such as those in the genera Penicillium and Aspergillus, may exchange genetic material via parasexual processes, initiated by anastomosis between hyphae and plasmogamy of fungal cells. The frequency and relative importance of parasexual events is unclear and may be lower than other sexual processes. It is known to play a role in intraspecific hybridization and is likely required for hybridization between species, which has been associated with major events in fungal evolution. Evolution In contrast to plants and animals, the early fossil record of the fungi is meager. Factors that likely contribute to the under-representation of fungal species among fossils include the nature of fungal fruiting bodies, which are soft, fleshy, and easily degradable tissues, and the microscopic dimensions of most fungal structures, which therefore are not readily evident. Fungal fossils are difficult to distinguish from those of other microbes, and are most easily identified when they resemble extant fungi. Often recovered from a permineralized plant or animal host, these samples are typically studied by making thin-section preparations that can be examined with light microscopy or transmission electron microscopy. Researchers study compression fossils by dissolving the surrounding matrix with acid and then using light or scanning electron microscopy to examine surface details. The earliest fossils possessing features typical of fungi date to the Paleoproterozoic era, some 2,400 million years ago (Ma); these multicellular benthic organisms had filamentous structures capable of anastomosis. Other studies (2009) estimate the arrival of fungal organisms at about 760–1060 Ma on the basis of comparisons of the rate of evolution in closely related groups. The oldest fossilizied mycelium to be identified from its molecular composition is between 715 and 810 million years old. For much of the Paleozoic Era (542–251 Ma), the fungi appear to have been aquatic and consisted of organisms similar to the extant chytrids in having flagellum-bearing spores. The evolutionary adaptation from an aquatic to a terrestrial lifestyle necessitated a diversification of ecological strategies for obtaining nutrients, including parasitism, saprobism, and the development of mutualistic relationships such as mycorrhiza and lichenization. Studies suggest that the ancestral ecological state of the Ascomycota was saprobism, and that independent lichenization events have occurred multiple times. In May 2019, scientists reported the discovery of a fossilized fungus, named Ourasphaira giraldae, in the Canadian Arctic, that may have grown on land a billion years ago, well before plants were living on land. Pyritized fungus-like microfossils preserved in the basal Ediacaran Doushantuo Formation (~635 Ma) have been reported in South China. Earlier, it had been presumed that the fungi colonized the land during the Cambrian (542–488.3 Ma), also long before land plants. Fossilized hyphae and spores recovered from the Ordovician of Wisconsin (460 Ma) resemble modern-day Glomerales, and existed at a time when the land flora likely consisted of only non-vascular bryophyte-like plants. Prototaxites, which was possibly a fungus or lichen, would have been the tallest organism of the late Silurian and early Devonian. Fungal fossils do not become common and uncontroversial until the early Devonian (416–359.2 Ma), when they occur abundantly in the Rhynie chert, mostly as Zygomycota and Chytridiomycota. At about this same time, approximately 400 Ma, the Ascomycota and Basidiomycota diverged, and all modern classes of fungi were present by the Late Carboniferous (Pennsylvanian, 318.1–299 Ma). Lichens formed a component of the early terrestrial ecosystems, and the estimated age of the oldest terrestrial lichen fossil is 415 Ma; this date roughly corresponds to the age of the oldest known sporocarp fossil, a Paleopyrenomycites species found in the Rhynie Chert. The oldest fossil with microscopic features resembling modern-day basidiomycetes is Palaeoancistrus, found permineralized with a fern from the Pennsylvanian. Rare in the fossil record are the Homobasidiomycetes (a taxon roughly equivalent to the mushroom-producing species of the Agaricomycetes). Two amber-preserved specimens provide evidence that the earliest known mushroom-forming fungi (the extinct species Archaeomarasmius leggetti) appeared during the late Cretaceous, 90 Ma. Some time after the Permian–Triassic extinction event (251.4 Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores in sediments) formed, suggesting that fungi were the dominant life form at this time, representing nearly 100% of the available fossil record for this period. However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess, the spike did not appear worldwide, and in many places it did not fall on the Permian–Triassic boundary. Sixty-five million years ago, immediately after the Cretaceous–Paleogene extinction event that famously killed off most dinosaurs, there was a dramatic increase in evidence of fungi; apparently the death of most plant and animal species led to a huge fungal bloom like "a massive compost heap". Although commonly included in botany curricula and textbooks, fungi are more closely related to animals than to plants, and are placed with the animals in the monophyletic group of opisthokonts. Analyses using molecular phylogenetics support a monophyletic origin of fungi. The taxonomy of fungi is in a state of constant flux, especially due to research based on DNA comparisons. These current phylogenetic analyses often overturn classifications based on older and sometimes less discriminative methods based on morphological features and biological species concepts obtained from experimental matings. There is no unique generally accepted system at the higher taxonomic levels and there are frequent name changes at every level, from species upwards. Efforts among researchers are now underway to establish and encourage usage of a unified and more consistent nomenclature. Until relatively recent (2012) changes to the International Code of Nomenclature for algae, fungi and plants, fungal species could also have multiple scientific names depending on their life cycle and mode (sexual or asexual) of reproduction. Web sites such as Index Fungorum and MycoBank are officially recognized nomenclatural repositories and list current names of fungal species (with cross-references to older synonyms). The 2007 classification of Kingdom Fungi is the result of a large-scale collaborative research effort involving dozens of mycologists and other scientists working on fungal taxonomy. It recognizes seven phyla, two of which—the Ascomycota and the Basidiomycota—are contained within a branch representing subkingdom Dikarya, the most species rich and familiar group, including all the mushrooms, most food-spoilage molds, most plant pathogenic fungi, and the beer, wine, and bread yeasts. The accompanying cladogram depicts the major fungal taxa and their relationship to opisthokont and unikont organisms, based on the work of Philippe Silar, "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research" and Tedersoo et al. 2018. The lengths of the branches are not proportional to evolutionary distances. Rozellomycetes Mitosporidium Paramicrosporidium Nucleophaga Metchnikovellea Microsporea Aphelidiomycetes Neocallimastigomycetes Hyaloraphidiomycetes Monoblepharidomycetes Sanchytriomycetes Mesochytriomycetes Chytridiomycetes Blastocladiomycetes Physodermatomycetes Basidiobolomyceta Olpidiomyceta Neozygitomycetes Entomophthoromycetes Zoopagomycetes Dimargaritomycetes Kickxellomycetes Mortierellomycetes Calcarisporiellomycetes Umbelopsidomycetes Mucoromycetes Paraglomeromycetes Archaeosporomycetes Glomeromycetes Entorrhizomycetes Basidiomycota Ascomycota Tritirachiomycetes Mixiomycetes Agaricostilbomycetes Cystobasidiomycetes Classiculaceae Microbotryomycetes Cryptomycocolacomycetes Atractiellomycetes Pucciniomycetes Monilielliomycetes Malasseziomycetes Ustilaginomycetes Exobasidiomycetes ?Geminibasidiomycetes ?Wallemiomycetes Bartheletiomycetes Tremellomycetes Dacrymycetes Agaricomycetes Neolectomycetes Taphrinomycetes Archaeorhizomycetes Pneumocystidomycetes Schizosaccharomycetes Saccharomycetes ?Thelocarpales ?Vezdaeales ?Lahmiales ?Triblidiales Orbiliomycetes Pezizomycetes Xylonomycetes Geoglossomycetes Leotiomycetes Laboulbeniomycetes Sordariomycetes Coniocybomycetes Lichinomycetes Eurotiomycetes Lecanoromycetes Collemopsidiomycetes Arthoniomycetes Dothideomycetes The major phyla (sometimes called divisions) of fungi have been classified mainly on the basis of characteristics of their sexual reproductive structures. As of 2019[update], nine major lineages have been identified: Opisthosporidia, Chytridiomycota, Neocallimastigomycota, Blastocladiomycota, Zoopagomycotina, Mucoromycota, Glomeromycota, Ascomycota, and Basidiomycota. Phylogenetic analysis has demonstrated that the Microsporidia, unicellular parasites of animals and protists, are fairly recent and highly derived endobiotic fungi (living within the tissue of another species). Previously considered to be "primitive" protozoa, they are now thought to be either a basal branch of the Fungi, or a sister group–each other's closest evolutionary relative. The Chytridiomycota are commonly known as chytrids. These fungi are distributed worldwide. Chytrids and their close relatives Neocallimastigomycota and Blastocladiomycota (below) are the only fungi with active motility, producing zoospores that are capable of active movement through aqueous phases with a single flagellum, leading early taxonomists to classify them as protists. Molecular phylogenies, inferred from rRNA sequences in ribosomes, suggest that the Chytrids are a basal group divergent from the other fungal phyla, consisting of four major clades with suggestive evidence for paraphyly or possibly polyphyly. The Blastocladiomycota were previously considered a taxonomic clade within the Chytridiomycota. Molecular data and ultrastructural characteristics, however, place the Blastocladiomycota as a sister clade to the Zygomycota, Glomeromycota, and Dikarya (Ascomycota and Basidiomycota). The blastocladiomycetes are saprotrophs, feeding on decomposing organic matter, and they are parasites of all eukaryotic groups. Unlike their close relatives, the chytrids, most of which exhibit zygotic meiosis, the blastocladiomycetes undergo sporic meiosis. The Neocallimastigomycota were earlier placed in the phylum Chytridiomycota. Members of this small phylum are anaerobic organisms, living in the digestive system of larger herbivorous mammals and in other terrestrial and aquatic environments enriched in cellulose (e.g., domestic waste landfill sites). They lack mitochondria but contain hydrogenosomes of mitochondrial origin. As in the related chrytrids, neocallimastigomycetes form zoospores that are posteriorly uniflagellate or polyflagellate. Members of the Glomeromycota form arbuscular mycorrhizae, a form of mutualist symbiosis wherein fungal hyphae invade plant root cells and both species benefit from the resulting increased supply of nutrients. All known Glomeromycota species reproduce asexually. The symbiotic association between the Glomeromycota and plants is ancient, with evidence dating to 400 million years ago. Formerly part of the Zygomycota (commonly known as 'sugar' and 'pin' molds), the Glomeromycota were elevated to phylum status in 2001 and now replace the older phylum Zygomycota. Fungi that were placed in the Zygomycota are now being reassigned to the Glomeromycota, or the subphyla incertae sedis Mucoromycotina, Kickxellomycotina, the Zoopagomycotina and the Entomophthoromycotina. Some well-known examples of fungi formerly in the Zygomycota include black bread mold (Rhizopus stolonifer), and Pilobolus species, capable of ejecting spores several meters through the air. Medically relevant genera include Mucor, Rhizomucor, and Rhizopus. The Ascomycota, commonly known as sac fungi or ascomycetes, constitute the largest taxonomic group within the Eumycota. These fungi form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This phylum includes morels, a few mushrooms and truffles, unicellular yeasts (e.g., of the genera Saccharomyces, Kluyveromyces, Pichia, and Candida), and many filamentous fungi living as saprotrophs, parasites, and mutualistic symbionts (e.g. lichens). Prominent and important genera of filamentous ascomycetes include Aspergillus, Penicillium, Fusarium, and Claviceps. Many ascomycete species have only been observed undergoing asexual reproduction (called anamorphic species), but analysis of molecular data has often been able to identify their closest teleomorphs in the Ascomycota. Because the products of meiosis are retained within the sac-like ascus, ascomycetes have been used for elucidating principles of genetics and heredity (e.g., Neurospora crassa). Members of the Basidiomycota, commonly known as the club fungi or basidiomycetes, produce meiospores called basidiospores on club-like stalks called basidia. Most common mushrooms belong to this group, as well as rust and smut fungi, which are major pathogens of grains. Other important basidiomycetes include the maize pathogen Ustilago maydis, human commensal species of the genus Malassezia, and the opportunistic human pathogen, Cryptococcus neoformans. Because of similarities in morphology and lifestyle, the slime molds (mycetozoans, plasmodiophorids, acrasids, Fonticula, and labyrinthulids, now in Amoebozoa, Rhizaria, Excavata, Cristidiscoidea, and Stramenopiles, respectively), water molds (oomycetes) and hyphochytrids (both Stramenopiles) were formerly classified in the kingdom Fungi, in groups like Mastigomycotina, Gymnomycota and Phycomycetes. The slime molds were studied also as protozoans, leading to an ambiregnal, duplicated taxonomy. Unlike true fungi, the cell walls of oomycetes contain cellulose and lack chitin. Hyphochytrids have both chitin and cellulose. Slime molds lack a cell wall during the assimilative phase (except labyrinthulids, which have a wall of scales), and take in nutrients by ingestion (phagocytosis, except labyrinthulids) rather than absorption (osmotrophy, as fungi, labyrinthulids, oomycetes and hyphochytrids). Neither water molds nor slime molds are closely related to the true fungi, and, therefore, taxonomists no longer group them in the kingdom Fungi. Nonetheless, studies of the oomycetes and myxomycetes are still often included in mycology textbooks and primary research literature. The Eccrinales and Amoebidiales are opisthokont protists, previously thought to be zygomycete fungi. Other groups now in Opisthokonta (e.g., Corallochytrium, Ichthyosporea) were also at given time classified as fungi. The genus Blastocystis, now in Stramenopiles, was originally classified as a yeast. Ellobiopsis, now in Alveolata, was considered a chytrid. The bacteria were also included in fungi in some classifications, as the group Schizomycetes. The Rozellida clade, including the "ex-chytrid" Rozella, is a genetically disparate group known mostly from environmental DNA sequences that is a sister group to fungi. Members of the group that have been isolated lack the chitinous cell wall that is characteristic of fungi. Alternatively, Rozella can be classified as a basal fungal group. The nucleariids may be the next sister group to the eumycete clade, and as such could be included in an expanded fungal kingdom. Many Actinomycetales (Actinomycetota), a group with many filamentous bacteria, were also long believed to be fungi. Ecology Although often inconspicuous, fungi occur in every environment on Earth and play very important roles in most ecosystems. Along with bacteria, fungi are the major decomposers in most terrestrial and aquatic ecosystems, and therefore play a critical role in biogeochemical cycles and in many food webs. As decomposers, they play an essential role in nutrient cycling, especially as saprotrophs and symbionts, degrading organic matter to inorganic molecules, which can then re-enter anabolic metabolic pathways in plants or other organisms. Many fungi have important symbiotic relationships with organisms from most if not all kingdoms. These interactions can be mutualistic or antagonistic in nature, or in the case of commensal fungi are of no apparent benefit or detriment to the host. Mycorrhizal symbiosis between plants and fungi is one of the most well-known plant–fungus associations and is of significant importance for plant growth and persistence in many ecosystems; over 90% of all plant species engage in mycorrhizal relationships with fungi and are dependent upon this relationship for survival. The mycorrhizal symbiosis is ancient, dating back to at least 400 million years. It often increases the plant's uptake of inorganic compounds, such as nitrate and phosphate from soils having low concentrations of these key plant nutrients. The fungal partners may also mediate plant-to-plant transfer of carbohydrates and other nutrients. Such mycorrhizal communities are called "common mycorrhizal networks". A special case of mycorrhiza is myco-heterotrophy, whereby the plant parasitizes the fungus, obtaining all of its nutrients from its fungal symbiont. Some fungal species inhabit the tissues inside roots, stems, and leaves, in which case they are called endophytes. Similar to mycorrhiza, endophytic colonization by fungi may benefit both symbionts; for example, endophytes of grasses impart to their host increased resistance to herbivores and other environmental stresses and receive food and shelter from the plant in return. Lichens are a symbiotic relationship between fungi and photosynthetic algae or cyanobacteria. The photosynthetic partner in the relationship is referred to in lichen terminology as a "photobiont". The fungal part of the relationship is composed mostly of various species of ascomycetes and a few basidiomycetes. Lichens occur in every ecosystem on all continents, play a key role in soil formation and the initiation of biological succession, and are prominent in some extreme environments, including polar, alpine, and semiarid desert regions. They are able to grow on inhospitable surfaces, including bare soil, rocks, tree bark, wood, shells, barnacles and leaves. As in mycorrhizas, the photobiont provides sugars and other carbohydrates via photosynthesis to the fungus, while the fungus provides minerals and water to the photobiont. The functions of both symbiotic organisms are so closely intertwined that they function almost as a single organism; in most cases the resulting organism differs greatly from the individual components. Lichenization is a common mode of nutrition for fungi; around 27% of known fungi—more than 19,400 species—are lichenized. Characteristics common to most lichens include obtaining organic carbon by photosynthesis, slow growth, small size, long life, long-lasting (seasonal) vegetative reproductive structures, mineral nutrition obtained largely from airborne sources, and greater tolerance of desiccation than most other photosynthetic organisms in the same habitat. Many insects also engage in mutualistic relationships with fungi. Several groups of ants cultivate fungi in the order Chaetothyriales for several purposes: as a food source, as a structural component of their nests, and as a part of an ant/plant symbiosis in the domatia (tiny chambers in plants that house arthropods). Ambrosia beetles cultivate various species of fungi in the bark of trees that they infest. Likewise, females of several wood wasp species (genus Sirex) inject their eggs together with spores of the wood-rotting fungus Amylostereum areolatum into the sapwood of pine trees; the growth of the fungus provides ideal nutritional conditions for the development of the wasp larvae. At least one species of stingless bee has a relationship with a fungus in the genus Monascus, where the larvae consume and depend on fungus transferred from old to new nests. Termites on the African savannah are also known to cultivate fungi, and yeasts of the genera Candida and Lachancea inhabit the gut of a wide range of insects, including neuropterans, beetles, and cockroaches; it is not known whether these fungi benefit their hosts. Fungi growing in dead wood are essential for xylophagous insects (e.g. woodboring beetles). They deliver nutrients needed by xylophages to nutritionally scarce dead wood. Thanks to this nutritional enrichment the larvae of the woodboring insect is able to grow and develop to adulthood. The larvae of many families of fungicolous flies, particularly those within the superfamily Sciaroidea such as the Mycetophilidae and some Keroplatidae feed on fungal fruiting bodies and sterile mycorrhizae. Many fungi are parasites on plants, animals (including humans), and other fungi. Serious pathogens of many cultivated plants causing extensive damage and losses to agriculture and forestry include the rice blast fungus Magnaporthe oryzae, tree pathogens such as Ophiostoma ulmi and Ophiostoma novo-ulmi causing Dutch elm disease, Cryphonectria parasitica responsible for chestnut blight, and Phymatotrichopsis omnivora causing Texas Root Rot, and plant pathogens in the genera Fusarium, Ustilago, Alternaria, and Cochliobolus. Some carnivorous fungi, like Purpureocillium lilacinum, are predators of nematodes, which they capture using an array of specialized structures such as constricting rings or adhesive nets. Many fungi that are plant pathogens, such as Magnaporthe oryzae, can switch from being biotrophic (parasitic on living plants) to being necrotrophic (feeding on the dead tissues of plants they have killed). This same principle is applied to fungi-feeding parasites, including Asterotremella albida, which feeds on the fruit bodies of other fungi both while they are living and after they are dead. Some fungi alter the behavior of their animal hosts in ways that spread their spores more effectively (also called "active host transmission"). Examples include Ophiocordyceps unilateralis and possibly the extinct Allocordyceps. Some fungi can cause serious diseases in humans, several of which may be fatal if untreated. These include aspergillosis, candidiasis, coccidioidomycosis, cryptococcosis, histoplasmosis, mycetomas, and paracoccidioidomycosis. Furthermore, a person with immunodeficiency is more susceptible to disease by genera such as Aspergillus, Candida, Cryptoccocus, Histoplasma, and Pneumocystis. Other fungi can attack eyes, nails, hair, and especially skin, the so-called dermatophytic and keratinophilic fungi, and cause local infections such as ringworm and athlete's foot. Fungal spores are also a cause of allergies, and fungi from different taxonomic groups can evoke allergic reactions. Organisms that parasitize fungi are known as mycoparasitic organisms. About 300 species of fungi and fungus-like organisms, belonging to 13 classes and 113 genera, are used as biocontrol agents against plant fungal diseases. Fungi can also act as mycoparasites or antagonists of other fungi, such as Hypomyces chrysospermus, which grows on bolete mushrooms. Fungi can also become the target of infection by mycoviruses. There appears to be electrical communication between fungi in word-like components according to spiking characteristics. According to a study published in the academic journal Current Biology, fungi can soak from the atmosphere around 36% of global fossil fuel greenhouse gas emissions. This is because mycorrhizal fungi that directly participate in photosynthesis create a network that holds the soil together at the same time. Such fungi are severly threatened by herbicides, fungicides, fertlizers, deforestation, pollution and covering soil with impermeable materials like concrete. Mycotoxins Many fungi produce biologically active compounds, several of which are toxic to animals or plants and are therefore called mycotoxins. Of particular relevance to humans are mycotoxins produced by molds causing food spoilage, and poisonous mushrooms (see above). Particularly infamous are the lethal amatoxins in some Amanita mushrooms, and ergot alkaloids, which have a long history of causing serious epidemics of ergotism (St Anthony's Fire) in people consuming rye or related cereals contaminated with sclerotia of the ergot fungus, Claviceps purpurea. Other notable mycotoxins include the aflatoxins, which are insidious liver toxins and highly carcinogenic metabolites produced by certain Aspergillus species often growing in or on grains and nuts consumed by humans, ochratoxins, patulin, and trichothecenes (e.g., T-2 mycotoxin) and fumonisins, which have significant impact on human food supplies or animal livestock. Mycotoxins are secondary metabolites (or natural products), and research has established the existence of biochemical pathways solely for the purpose of producing mycotoxins and other natural products in fungi. Mycotoxins may provide fitness benefits in terms of physiological adaptation, competition with other microbes and fungi, and protection from consumption (fungivory). Many fungal secondary metabolites (or derivatives) are used medically, as described under Human use below. Pathogenic mechanisms Ustilago maydis is a pathogenic plant fungus that causes smut disease in maize and teosinte. Plants have evolved efficient defense systems against pathogenic microbes such as U. maydis. A rapid defense reaction after pathogen attack is the oxidative burst where the plant produces reactive oxygen species at the site of the attempted invasion. U. maydis can respond to the oxidative burst with an oxidative stress response, regulated by the gene YAP1. The response protects U. maydis from the host defense, and is necessary for the pathogen's virulence. Furthermore, U. maydis has a well-established recombinational DNA repair system which acts during mitosis and meiosis. The system may assist the pathogen in surviving DNA damage arising from the host plant's oxidative defensive response to infection. Cryptococcus neoformans is an encapsulated yeast that can live in both plants and animals. C. neoformans usually infects the lungs, where it is phagocytosed by alveolar macrophages. Some C. neoformans can survive inside macrophages, which appears to be the basis for latency, disseminated disease, and resistance to antifungal agents. One mechanism by which C. neoformans survives the hostile macrophage environment is by up-regulating the expression of genes involved in the oxidative stress response. Another mechanism involves meiosis. The majority of C. neoformans are mating "type a". Filaments of mating "type a" ordinarily have haploid nuclei, but they can become diploid (perhaps by endoduplication or by stimulated nuclear fusion) to form blastospores. The diploid nuclei of blastospores can undergo meiosis, including recombination, to form haploid basidiospores that can be dispersed. This process is referred to as monokaryotic fruiting. This process requires a gene called DMC1, which is a conserved homologue of genes recA in bacteria and RAD51 in eukaryotes, that mediates homologous chromosome pairing during meiosis and repair of DNA double-strand breaks. Thus, C. neoformans can undergo a meiosis, monokaryotic fruiting, that promotes recombinational repair in the oxidative, DNA damaging environment of the host macrophage, and the repair capability may contribute to its virulence. Human use The human use of fungi for food preparation or preservation and other purposes is extensive and has a long history. Mushroom farming and mushroom gathering are large industries in many countries. The study of the historical uses and sociological impact of fungi is known as ethnomycology. Because of the capacity of this group to produce an enormous range of natural products with antimicrobial or other biological activities, many species have long been used or are being developed for industrial production of antibiotics, vitamins, and anti-cancer and cholesterol-lowering drugs. Methods have been developed for genetic engineering of fungi, enabling metabolic engineering of fungal species. For example, genetic modification of yeast species—which are easy to grow at fast rates in large fermentation vessels—has opened up ways of pharmaceutical production that are potentially more efficient than production by the original source organisms. Fungi-based industries are sometimes considered to be a major part of a growing bioeconomy, with applications under research and development including use for textiles, meat substitution and general fungal biotechnology. Many species produce metabolites that are major sources of pharmacologically active drugs. Particularly important are the antibiotics, including the penicillins, a structurally related group of β-lactam antibiotics that are synthesized from small peptides. Although naturally occurring penicillins such as penicillin G (produced by Penicillium chrysogenum) have a relatively narrow spectrum of biological activity, a wide range of other penicillins can be produced by chemical modification of the natural penicillins. Modern penicillins are semisynthetic compounds, obtained initially from fermentation cultures, but then structurally altered for specific desirable properties. Other antibiotics produced by fungi include: ciclosporin, commonly used as an immunosuppressant during transplant surgery; and fusidic acid, used to help control infection from methicillin-resistant Staphylococcus aureus bacteria. Widespread use of antibiotics for the treatment of bacterial diseases, such as tuberculosis, syphilis, leprosy, and others began in the early 20th century and continues to date. In nature, antibiotics of fungal or bacterial origin appear to play a dual role: at high concentrations they act as chemical defense against competition with other microorganisms in species-rich environments, such as the rhizosphere, and at low concentrations as quorum-sensing molecules for intra- or interspecies signaling. Other drugs produced by fungi include griseofulvin isolated from Penicillium griseofulvum, used to treat fungal infections, and statins (HMG-CoA reductase inhibitors), used to inhibit cholesterol synthesis. Examples of statins found in fungi include mevastatin from Penicillium citrinum and lovastatin from Aspergillus terreus and the oyster mushroom. Psilocybin from fungi is investigated for therapeutic use and appears to cause global increases in brain network integration. Fungi produce compounds that inhibit viruses and cancer cells. Specific metabolites, such as polysaccharide-K, ergotamine, and β-lactam antibiotics, are routinely used in clinical medicine. The shiitake mushroom is a source of lentinan, a clinical drug approved for use in cancer treatments in several countries, including Japan. In Europe and Japan, polysaccharide-K (brand name Krestin), a chemical derived from Trametes versicolor, is an approved adjuvant for cancer therapy. Certain mushrooms are used as supposed therapeutics in folk medicine practices, such as traditional Chinese medicine. Mushrooms with a history of such use include Agaricus subrufescens, Ganoderma lucidum, and Ophiocordyceps sinensis. Baker's yeast or Saccharomyces cerevisiae, a unicellular fungus, is used to make bread and other wheat-based products, such as pizza dough and dumplings. Yeast species of the genus Saccharomyces are also used to produce alcoholic beverages through fermentation. Shoyu koji mold (Aspergillus oryzae) is an essential ingredient in brewing shoyu (soy sauce) and sake, and the preparation of miso, while Rhizopus species are used for making tempeh. Several of these fungi are domesticated species that were bred or selected according to their capacity to ferment food without producing harmful mycotoxins (see below), which are produced by very closely related Aspergilli. Quorn, a meat alternative, is made from Fusarium venenatum. Edible mushrooms include commercially raised and wild-harvested fungi. Agaricus bisporus, sold as button mushrooms when small or Portobello mushrooms when larger, is the most widely cultivated species in the West, used in salads, soups, and many other dishes. Many Asian fungi are commercially grown and have increased in popularity in the West. They are often available fresh in grocery stores and markets, including straw mushrooms (Volvariella volvacea), oyster mushrooms (Pleurotus spp.), shiitakes (Lentinula edodes), and enokitake (Flammulina spp.). Many other mushroom species are harvested from the wild for personal consumption or commercial sale. Milk mushrooms, morels, chanterelles, truffles, black trumpets, and porcini mushrooms (Boletus edulis) (also known as king boletes) demand a high price on the market. They are often used in gourmet dishes. Certain types of cheeses require inoculation of milk curds with fungal species that impart a unique flavor and texture to the cheese. Examples include the blue color in cheeses such as Stilton or Roquefort, which are made by inoculation with Penicillium roqueforti. Molds used in cheese production are non-toxic and are thus safe for human consumption; however, mycotoxins (e.g., aflatoxins, roquefortine C, patulin, or others) may accumulate because of growth of other fungi during cheese ripening or storage. Many mushroom species are poisonous to humans and cause a range of reactions including slight digestive problems, allergic reactions, hallucinations, severe organ failure, and death. Genera with mushrooms containing deadly toxins include, not are not limited to Conocybe, Galerina, Lepiota and infamously, Amanita. The latter genus the death cap (A. phalloides), the most common cause of deadly mushroom poisoning. In particular, Amanita sect. Phalloideae contains dozens of amatoxin-containing species, including A. phalloides as well as the destroying angels. The false morel (Gyromitra esculenta) is occasionally considered a delicacy when cooked, yet can be highly toxic when eaten raw. Tricholoma equestre was considered edible until it was implicated in serious poisonings causing rhabdomyolysis. Fly agaric mushrooms (Amanita muscaria) also cause occasional non-fatal poisonings, mostly as a result of ingestion for its hallucinogenic properties. Historically, fly agaric was used by different peoples in Europe and Asia and its present usage for religious or shamanic purposes is reported from some ethnic groups such as the Koryak people of northeastern Siberia. As it is difficult to accurately identify a safe mushroom without proper training and knowledge, it is often advised to assume that a wild mushroom is poisonous and not to consume it. In agriculture, fungi may be useful if they actively compete for nutrients and space with pathogenic microorganisms such as bacteria or other fungi via the competitive exclusion principle, or if they are parasites of these pathogens. For example, certain species eliminate or suppress the growth of harmful plant pathogens, such as insects, mites, weeds, nematodes, and other fungi that cause diseases of important crop plants. This has generated strong interest in practical applications that use these fungi in the biological control of these agricultural pests. Entomopathogenic fungi can be used as biopesticides, as they actively kill insects. Examples that have been used as biological insecticides are Beauveria bassiana, Metarhizium spp., Hirsutella spp., Paecilomyces (Isaria) spp., and Lecanicillium lecanii. Endophytic fungi of grasses of the genus Epichloë, such as E. coenophiala, produce alkaloids that are toxic to a range of invertebrate and vertebrate herbivores. These alkaloids protect grass plants from herbivory, but several endophyte alkaloids can poison grazing animals, such as cattle and sheep. Infecting cultivars of pasture or forage grasses with Epichloë endophytes is one approach being used in grass breeding programs; the fungal strains are selected for producing only alkaloids that increase resistance to herbivores such as insects, while being non-toxic to livestock. Certain fungi, in particular white-rot fungi, can degrade insecticides, herbicides, pentachlorophenol, creosote, coal tars, and heavy fuels and turn them into carbon dioxide, water, and basic elements. Fungi have been shown to biomineralize uranium oxides, suggesting they may have application in the bioremediation of radioactively polluted sites. Several pivotal discoveries in biology were made by researchers using fungi as model organisms, that is, fungi that grow and sexually reproduce rapidly in the laboratory. For example, the one gene-one enzyme hypothesis was formulated by scientists using the bread mold Neurospora crassa to test their biochemical theories. Other important model fungi are Aspergillus nidulans and the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, each of which with a long history of use to investigate issues in eukaryotic cell biology and genetics, such as cell cycle regulation, chromatin structure, and gene regulation. Other fungal models have emerged that address specific biological questions relevant to medicine, plant pathology, and industrial uses; examples include Candida albicans, a dimorphic, opportunistic human pathogen, Magnaporthe grisea, a plant pathogen, and Pichia pastoris, a yeast widely used for eukaryotic protein production. Fungi are used extensively to produce industrial chemicals like citric, gluconic, lactic, and malic acids, and industrial enzymes, such as lipases used in biological detergents, cellulases used in making cellulosic ethanol and stonewashed jeans, and amylases, invertases, proteases, and xylanases. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Enthought] | [TOKENS: 172] |
Contents Enthought Enthought, Inc. is a software company based in Austin, Texas that develops scientific and analytic computing solutions using primarily the Python programming language. It is best known for the early development and maintenance of the SciPy library of mathematics, science, and engineering algorithms and for its Python for scientific computing distribution Enthought Canopy (formerly EPD). The company was founded in 2001 by Travis Vaught and Eric Jones. Open source software Enthought publishes a large portion of the code as open-source software under a BSD-style license. Enthought Canopy is a Python for scientific and analytic computing distribution and analysis environment, available for free and under a commercial license. The Enthought Tool Suite open source software projects include: See also References External links This United States software corporation or company article is a stub. You can help Wikipedia by adding missing information. |
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[SOURCE: https://en.wikipedia.org/wiki/Arab_world] | [TOKENS: 9103] |
Contents Arab world The Arab world (Arabic: اَلْعَالَمُ الْعَرَبِيُّ al-ʿālam al-ʿarabī), formally the Arab homeland (اَلْوَطَنُ الْعَرَبِيُّ al-waṭan al-ʿarabī), also known as the Arab nation (اَلْأُمَّةُ الْعَرَبِيَّةُ al-ummah al-ʿarabiyyah), the Arabsphere, or the Arab states, comprises a large group of countries, mainly located in West Asia and North Africa. While the majority of people in the Arab world are ethnically Arab, there are also significant populations of other ethnic groups such as Berbers, Kurds, Somalis and Nubians, among other groups. Arabic is used as the lingua franca throughout the Arab world. The Arab world is at its minimum defined as the 19 states where Arabs form at least a plurality of the population. At its maximum it consists of the 22 members of the Arab League, an international organization, which on top of the 19 plurality Arab states also includes the Bantu-speaking Comoros, and the Cushitic-speaking Djibouti and Somalia. The region stretches from the Atlantic Ocean in the west to the Arabian Sea in the east, and from the Mediterranean Sea in the north to the Indian Ocean in the southeast. The eastern part of the Arab world is known as the Mashriq, and the western part as the Maghreb. According to the World Bank, the Arab world has a total population of 456 million inhabitants and a gross domestic product of $2.85 trillion, as of 2021. The region is economically quite diverse, and includes some of the wealthiest as well as poorest populations in the world. In post-classical history, the Arab world was synonymous with the historic Arab empires and caliphates. Arab nationalism arose in the second half of the 19th century along with other nationalist movements within the Ottoman Empire. The Arab League was formed in 1945 to represent the interests of Arab people and especially to pursue the political unification of the Arab countries, a project known as pan-Arabism. Terminology In page 9 of Best Divisions for Knowledge of the Regions, 10th century Arab geographer Al Maqdisi used the term Arab regions[a] to refer to the lands of the Arabian Peninsula (Bahrain, Iraq, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates and Yemen). He also considered Iraq, alongside Upper Mesopotamia (Iraq, Syria and Turkey), Ash-Sham (Israel, Jordan, Lebanon, Palestine, Syria and Turkey), Egypt and the Maghreb (Algeria, Libya, Mauritania, Morocco, Tunisia and Western Sahara Sahrawi Arab Democratic Republic) to be part of the Arab regions. Malta, an island country in Southern Europe whose national language derives from Arabic (through Sicilian Arabic), is not included in the region. Similarly, Chad, Eritrea and Israel recognize Arabic as one of their official or working languages but are not included in the region because they are not members of the Arab League.[citation needed] Definition The linguistic and political denotation inherent in the term Arab is generally dominant over genealogical considerations. In Arab states, Standard Arabic is used by the government. Local vernacular languages are referred to as Darija (الدَّارِجَة "everyday/colloquial language") in the Maghreb or Aammiyya (ٱلْعَامِيَّة "common language") in the Mashreq. The majority of the vocabulary in these vernaculars is shared with Standard Arabic; however, some of them also significantly borrow from other languages, such as Berber, French, Spanish and Italian in the Maghreb. Although no globally accepted definition of the Arab world exists, all countries that are members of the Arab League are generally acknowledged as being part of the Arab world. The Arab League is a regional organisation that aims, among other things, to consider in a general way the affairs and interests of the Arab countries and sets out the following definition of an Arab: An Arab is a person whose language is Arabic, who lives in an Arab country, and who is in sympathy with the aspirations of the Arab people. This standard territorial definition is sometimes seen to be inappropriate or problematic, and may be supplemented with certain additional elements (see ancillary linguistic definition below). As an alternative to, or in combination with, the standard territorial definition, the Arab world may be defined as consisting of peoples and states united to at least some degree by Arabic language, culture or geographic contiguity, or those states or territories in which the majority of the population speaks Arabic, and thus may also include populations of the Arab diaspora. When an ancillary linguistic definition is used in combination with the standard territorial definition, various parameters may be applied[clarification needed] to determine whether a state or territory should be included in this alternative definition of the Arab world. These parameters may be applied[clarification needed] to the states and territories of the Arab League (which constitute the Arab world under the standard definition) and to other states and territories. Typical parameters that may be applied include: whether Arabic is widely spoken; whether Arabic is an official or national language; or whether an Arabic cognate language is widely spoken. While Arabic dialects are spoken in a number of Arab League states, Literary Arabic is official in all of them. Several states have declared Arabic to be an official or national language, although Arabic is not as widely spoken there. As members of the Arab League, however, they are considered part of the Arab world under the standard territorial definition. Somalia has two official languages, Arabic and Somali, while Somaliland has three, Arabic, Somali and English. Both Arabic and Somali belong to the larger Afro-Asiatic language family. Although Arabic is widely spoken by many people in the north and urban areas in the south, Somali is the most widely used language, and contains many Arabic loan words. Similarly, Djibouti has two official languages, Arabic and French. It also has several formally recognized national languages; besides Somali, many people speak Afar, which is also an Afro-Asiatic language. The majority of the population speaks Somali and Afar, although Arabic is also widely used for trade and other activities. The Comoros has three official languages: Arabic, Comorian and French. Comorian is the most widely spoken language, with Arabic having a religious significance, and French being associated with the educational system. Chad, Eritrea and Israel all recognize Arabic as an official or working language, but none of them is a member-state of the Arab League, although both Chad and Eritrea are observer states of the League (with possible future membership) and have large populations of Arabic speakers. Israel is not a part of the Arab world. By some definitions, Arab citizens of Israel may concurrently be considered a constituent part of the Arab world. Iran has about 1.5 million Arabic speakers. Iranian Arabs are mainly found in Ahvaz, a southwestern region in the Khuzestan Province; others inhabit the Bushehr and Hormozgan provinces and the city of Qom. Mali and Senegal recognize Hassaniya, the Arabic dialect of the Moorish ethnic minority, as a national language. Greece and Cyprus also recognize Cypriot Maronite Arabic under the European Charter for Regional or Minority Languages. Additionally, Malta, though not part of the Arab world, has as its official language Maltese. The language is grammatically akin to Maghrebi Arabic. History The Arabs historically originate as a Central Semitic group in the northern Arabian Peninsula, the Southern Levant and the Syrian Desert. Arab tribes and federations included the Nabataeans, Tanukhids, Salihids, Ghassanids. Arab expansion is due to the early Muslim conquests of the 7th and 8th centuries. Iraq was conquered in 633, Levant (modern Syria, Israel, Palestine, Jordan and Lebanon) was conquered between 636 and 640 CE. Egypt was conquered in 639, and gradually Arabized during the medieval period. A distinctively Egyptian Arabic language emerged by the 16th century. The Maghreb was also conquered in the 7th century, and gradually Arabized under the Fatimids. Islam was brought to Sudan from Egypt during the 8th to 11th centuries. The culture of Sudan today depends on the tribe, some have a pure Nubian, Beja, or Arabic culture and some have a mixture of Arab and Nubian elements. The Arab Abbasid Caliphate fell to the Mongol invasions in the 13th century. Egypt, the Levant and Hejaz also came under the Turkish Mamluk Sultanate. By 1570, the Turkish Ottoman Empire controlled most of the Arab world. However, Morocco remained under the rule of the Zenata Wattasid dynasty, which was succeeded by the Saadi dynasty in the 16th to 17th centuries. The Ajuran Sultanate also held sway in the southern part of the Horn region. The sentiment of Arab nationalism arose in the second half of the 19th century along with other nationalisms within the declining Ottoman Empire. When the Ottoman Empire collapsed as a result of World War I, much of the Arab world came to be controlled by the European colonial empires: Mandatory Palestine, Mandatory Iraq, British protectorate of Egypt, French protectorate of Morocco, Italian Libya, French Tunisia, French Algeria, Mandate for Syria and the Lebanon and the so-called Trucial States, a British protectorate formed by the sheikhdoms on the former "Pirate Coast". These Arab states only gained their independence during or after World War II: the Republic of Lebanon in 1943, the Syrian Arab Republic and the Hashemite Kingdom of Jordan in 1946, the Kingdom of Libya in 1951, the Kingdom of Egypt in 1952, the Kingdom of Morocco and Tunisia in 1956, the Republic of Iraq in 1958, the Somali Republic in 1960, Algeria in 1962, and the United Arab Emirates in 1971. By contrast, Saudi Arabia had fragmented with the fall of the Ottoman Empire, and was unified under Ibn Saud of Saudi Arabia by 1932. The Mutawakkilite Kingdom of Yemen also seceded directly from the Ottoman Empire in 1918. Oman, apart from brief intermittent Persian and Portuguese rule, has been self-governing since the 8th century. The Arab League was formed in 1945 to represent the interests of the Arabs, and especially to pursue the political unification of the Arab world, a project known as Pan-Arabism. There were some short-lived attempts at such unification in the mid-20th century, notably the United Arab Republic of 1958 to 1961. The Arab League's main goal is to unify politically the Arab populations so defined. Its permanent headquarters are located in Cairo. However, it was moved temporarily to Tunis during the 1980s, after Egypt was expelled for signing the Camp David Accords (1978). Pan-Arabism has mostly been abandoned as an ideology since the 1980s, and was replaced by Pan-Islamism on one hand, and individual nationalisms on the other. The unification of Saudi Arabia was a 30-year-long military and political campaign, by which the various tribes, sheikhdoms, and emirates of most of the Arabian Peninsula were conquered by the House of Saud, or Al Saud, between 1902 and 1932, when the modern-day Kingdom of Saudi Arabia was proclaimed. Carried out under the charismatic Abdul Aziz Ibn Saud, this process created what is sometimes referred to as the Third Saudi State, to differentiate it from the first and second states that existed under the Al Saud clan. The Al-Saud had been in exile in Ottoman Iraq since 1893 following the disintegration of the Second Saudi State and the rise of Jebel Shammar under the Al Rashid clan. In 1902, Ibn Saud recaptured Riyadh, the Al Saud dynasty's former capital. He went on to subdue the rest of Nejd, Al-Hasa, Jebel Shammar, Asir, and Hejaz (location of the Muslim holy cities of Mecca and Medina) between 1913 and 1926. The resultant polity was named the Kingdom of Nejd and Hejaz from 1927 until it was further consolidated with Al-Hasa and Qatif into the Kingdom of Saudi Arabia in 1932. The establishment of the State of Israel in 1948 has given rise to the Arab–Israeli conflict, one of the major unresolved geopolitical conflicts. The Arab states in changing alliances were involved in a number of wars with Israel and its western allies between 1948 and 1973, including the 1948 Arab–Israeli War, the 1956 Suez Crisis, the Six-Day War of 1967, and the Yom Kippur War of 1973. An Egypt–Israel peace treaty was signed in 1979. The Iran–Iraq War (also known as the First Gulf War and by various other names) was an armed conflict between the armed forces of Iraq and Iran, lasting from September 1980 to August 1988, making it the second longest conventional war of the 20th century. It was initially referred to in English as the "Gulf War" prior to the "Gulf War" of 1990. The war began when Iraq invaded Iran, launching a simultaneous invasion by air and land into Iranian territory on 22 September 1980 following a long history of border disputes, and fears of Shia Islam insurgency among Iraq's long-suppressed Shia majority influenced by the Iranian Revolution. Iraq was also aiming to replace Iran as the dominant Persian Gulf state. Although Iraq hoped to take advantage of the revolutionary chaos in Iran (see Iranian Revolution, 1979) and attacked without formal warning, they made only limited progress into Iran and were quickly repelled by the Iranians who regained virtually all lost territory by June 1982. For the next six years, Iran was on the offensive. The Lebanese Civil War was a multifaceted civil war in Lebanon, lasting from 1975 to 1990 and resulting in an estimated 120,000 fatalities. Another one million people (a quarter of the population) were wounded,[citation needed] and today approximately 76,000 people remain displaced within Lebanon. There was also a mass exodus of almost one million people from Lebanon. The Western Sahara War was an armed struggle between the Sahrawi Polisario Front and Morocco between 1975 and 1991, being the most significant phase of the Western Sahara conflict. The conflict erupted after the withdrawal of Spain from the Spanish Sahara in accordance with the Madrid Accords, by which it transferred administrative control of the territory to Morocco and Mauritania, but not the sovereignty. In 1975, Moroccan government organized the Green March of some 350,000 Moroccan citizens, escorted by around 20,000 troops, who entered Western Sahara, trying to establish Moroccan presence. While at first met with just minor resistance by the Polisario, Morocco later engaged a long period of guerilla warfare with the Sahrawi nationalists. During the late 1970s, the Polisario Front, desiring to establish an independent state in the territory, successively fought both Mauritania and Morocco. In 1979, Mauritania withdrew from the conflict after signing a peace treaty with the Polisario. The war continued in low intensity throughout the 1980s, though Morocco made several attempts to take the upper hand in 1989–1991. A cease-fire agreement was finally reached between the Polisario Front and Morocco in September 1991. The North Yemen Civil War was fought in North Yemen between royalists of the Mutawakkilite Kingdom of Yemen and factions of the Yemen Arab Republic from 1962 to 1970. The war began with a coup d'état carried out by the republican leader, Abdullah as-Sallal, which dethroned the newly crowned Imam al-Badr and declared Yemen a republic under his presidency. The Imam escaped to the Saudi Arabian border and rallied popular support. The Somali Civil War is an ongoing civil war taking place in Somalia. It began in 1991, when a coalition of clan-based armed opposition groups ousted the nation's long-standing military government. Various factions began competing for influence in the power vacuum that followed, which precipitated an aborted UN peacekeeping attempt in the mid-1990s. A period of decentralization ensued, characterized by a return to customary and religious law in many areas as well as the establishment of autonomous regional governments in the northern part of the country. The early 2000s saw the creation of fledgling interim federal administrations, culminating in the establishment of the Transitional Federal Government (TFG) in 2004. In 2006, the TFG, assisted by Ethiopian troops, assumed control of most of the nation's southern conflict zones from the newly formed Islamic Courts Union (ICU). The ICU splintered into more radical groups, notably Al-Shabaab, which have since been fighting the Somali government and its AMISOM allies for control of the region. In 2011, a coordinated military operation between the Somali military and multinational forces began, which is believed to represent one of the final stages in the war's Islamist insurgency. The popular protests throughout the Arab world of late 2010 to the present have been directed against authoritarian leadership and associated political corruption, paired with demands for more democratic rights. The two most violent and prolonged conflicts in the aftermath of the Arab Spring are the Libyan Civil War and Syrian Civil War. While the Arab world had been of limited interest to the European colonial powers, the British Empire being mostly interested in the Suez Canal as a route to British India, the economic and geopolitical situation changed dramatically after the discovery of large petroleum deposits in the 1930s, coupled with the vastly increased demand for petroleum in the west as a result of the Second Industrial Revolution. The Persian Gulf is particularly well-endowed with this strategic raw material: five Persian Gulf states, Saudi Arabia, Iraq, the UAE, Kuwait, and Qatar, are among the top ten petroleum or gas exporters worldwide. In Africa, Algeria (10th world) and Libya are important gas exporters. Bahrain, Egypt, Tunisia, and Sudan all have smaller but significant reserves. Where present, these have had significant effects on regional politics, often enabling rentier states, leading to economic disparities between oil-rich and oil-poor countries, and, particularly in the more sparsely populated states of the Persian Gulf and Libya, triggering extensive labor immigration. It is believed that the Arab world holds approximately 46% of the world's total proven oil reserves and a quarter of the world's natural-gas reserves. Islamism and Pan-Islamism were on the rise during the 1980s. The Hezbollah, a militant Islamic party in Lebanon, was founded in 1982. Islamic terrorism became a problem in the Arab world in the 1970s to 1980s. While the Muslim Brotherhood had been active in Egypt since 1928, their militant actions were limited to assassination attempts on political leaders. Today, Arab states are characterized by their autocratic rulers and lack of democratic control. The 2016 Democracy Index classifies Lebanon, Iraq and Palestine as "hybrid regimes", Tunisia as a "flawed democracy" and all other Arab states as "authoritarian regimes". Similarly, the 2011 Freedom House report classifies the Comoros and Mauritania as "electoral democracies", Lebanon, Kuwait and Morocco as "partly free", and all other Arab states as "not free". The invasion of Kuwait by Iraq forces, led to the 1990–91 Persian Gulf War. Egypt, Syria and Saudi Arabia joined a multinational coalition that opposed Iraq. Displays of support for Iraq by Jordan and Palestine resulted in strained relations between many of the Arab states. After the war, a so-called "Damascus Declaration" formalized an alliance for future joint Arab defensive actions between Egypt, Syria, and the GCC states. A chain of events leading to the destabilization of the authoritarian regimes established during the 1950s throughout the Arab world became apparent during the early years of the 21st century. The 2003 U.S. invasion of Iraq led to the collapse of the Baathist regime and ultimate execution of Saddam Hussein. A growing class of young, educated, secular citizens with access to modern media such as Al Jazeera (since 1996) and communicating via the internet began to form a third force besides the classical dichotomy of Pan-Arabism vs. Pan-Islamism that had dominated the second half of the 20th century. These citizens wish for reform in their country's religious institutions. In Syria, the Damascus Spring of 2000 to 2001 heralded the possibility of democratic change, but the Baathist regime managed to suppress the movement. In 2003, the Egyptian Movement for Change, popularly known as Kefaya, was launched to oppose the Mubarak regime and to establish democratic reforms and greater civil liberties in Egypt. Geography The Arab World stretches across more than 13,000,000 square kilometres (5,000,000 sq mi)[citation needed] of North Africa and the part of North-East Africa and South-West Asia. The eastern part of the Arab world is called the Mashriq. Algeria, Morocco, Tunisia, Libya and Mauritania are the Maghreb or Maghrib.[citation needed] The term "Arab" often connotes[according to whom?] the Arabian Peninsula, but the larger (and more populous) part of the Arab World is North Africa. Its eight million square kilometers include two of the largest countries of the African continent, Algeria (2.4 million km2) in the center of the region and Sudan (1.9 million km2) in the southeast.[citation needed] Algeria is about three-quarters the size of India, or about one-and-a-half times the size of Alaska, the largest state in the United States. The largest country in the Arab West Asia is Saudi Arabia (2 million km2).[citation needed] At the other extreme, the smallest autonomous mainland Arab country is Lebanon (10,452 km2), and the smallest island Arab country is Bahrain (665 km2).[citation needed] Every Arab country borders a sea or ocean, with the exception of the Arab region of northern Chad, which is completely landlocked.[citation needed] Iraq is actually nearly landlocked, as it has only a very narrow access to the Persian Gulf.[citation needed] The political borders of the Arab world have wandered, leaving Arab minorities in non-Arab countries of the Sahel and the Horn of Africa as well as in the Middle Eastern countries of Cyprus, Turkey and Iran, and also leaving non-Arab minorities in Arab countries. However, the basic geography of sea, desert and mountain provides the enduring natural boundaries for this region.[citation needed] The Arab world straddles two continents, Africa and Asia. It is mainly oriented along an east–west axis.[citation needed] The West Asian Arab region comprises the Arabian Peninsula, most of the Levant (excluding Cyprus and Israel), most of Mesopotamia (excluding parts of Turkey and Iran) and the Persian Gulf region. The peninsula is roughly a tilted rectangle that leans back against the slope of northeast Africa, the long axis pointing toward Turkey and Europe.[citation needed] Arab North Africa comprises the entire northern third of the continent. It is surrounded by water on three sides (west, north, and east) and desert or desert scrubland on the fourth (south).[citation needed] In the west, it is bounded by the shores of the Atlantic Ocean. From northeast to southwest, Morocco, Western Sahara (mostly unilaterally annexed by Morocco), and Mauritania make up the roughly 2,000 kilometers of Arab Atlantic coastline. The southwestern sweep of the coast is gentle but substantial, such that Mauritania's capital, Nouakchott (18°N, 16°W), is far enough west to share longitude with Iceland (13–22°W). Nouakchott is the westernmost capital of the Arab World and the third-westernmost in Africa, and sits on the Atlantic fringe of the southwestern Sahara. Next south along the coast from Mauritania is Senegal, whose abrupt border belies the gradient in culture from Arab to indigenous African that historically characterizes this part of West Africa.[citation needed] Arab Africa's boundary to the north is again a continental boundary, the Mediterranean Sea. This boundary begins in the west with the narrow Strait of Gibraltar, the thirteen kilometer wide channel that connects the Mediterranean with the Atlantic to the west, and separates Morocco from Spain to the north. East along the coast from Morocco are Algeria, Tunisia, and Libya, followed by Egypt, which forms the region's, and the continent's, northeastern corner. The coast turns briefly but sharply south at Tunisia, slopes more gently southeastward through the Libyan capital of Tripoli, and bumps north through Libya's second city, Benghazi, before turning straight east again through Egypt's second city, Alexandria, at the mouth of the Nile. Along with the spine of Italy to its north, Tunisia marks the junction of western and eastern Mediterranean, and a cultural transition as well: west of Egypt begins the region of the Arab World known as the Maghreb include (Libya, Tunisia, Algeria, Morocco and Mauritania).[citation needed] Historically the 4,000-kilometer Mediterranean boundary has fluttered. Population centers north of it in Europe have invited contact and Arab exploration—mostly friendly, though sometimes not. Islands and peninsulas near the Arab coast have changed hands. The islands of Sicily and Malta lie just a hundred kilometers east of the Tunisian city of Carthage, which has been a point of contact with Europe since its founding in the first millennium BCE; both Sicily and Malta at times have been part of the Arab World. Just across the Strait of Gibraltar from Morocco, regions of the Iberian peninsula were part of the Arab World throughout the Middle Ages, extending the northern boundary at times to the foothills of the Pyrenees and leaving a substantial mark on local and wider European and Western culture.[citation needed] The northern boundary of the African Arab world has also fluttered briefly in the other direction, first through the Crusades and later through the imperial involvement of France, Britain, Spain, and Italy. Another visitor from northern shores, Turkey, controlled the east of the region for centuries, though not as a colonizer. Spain still maintains two small enclaves, Ceuta and Melilla (called "Morocco Espanol"), along the otherwise Moroccan coast. Overall this wave has ebbed, though like the Arab expansion north it has left its mark. The proximity of North Africa to Europe has always encouraged interaction, and this continues with Arab immigration to Europe and European interest in the Arab countries today. However, population centers and the physical fact of the sea keeps this boundary of the Arab World settled on the Mediterranean coastline.[citation needed] To the east, the Red Sea defines the boundary between Africa and Asia, and thus also between Arab Africa and Arab West Asia. This sea is a long and narrow waterway with a northwest tilt, stretching 2,300 kilometers from Egypt's Sinai Peninsula southeast to the Bab-el-Mandeb strait between Djibouti in Africa and Yemen in Arabia but on average just 150 kilometers wide. Though the sea is navigable along its length, historically much contact between Arab Africa and Arab West Asia has been either overland across the Sinai or by sea across the Mediterranean or the narrow Bab al Mendeb strait. From northwest to southeast, Egypt, Sudan, and Eritrea form the African coastline, with Djibouti marking Bab al Mendeb's African shore.[citation needed] Southeast along the coast from Djibouti is Somalia, but the Somali coast soon makes a 90-degree turn and heads northeast, mirroring a bend in the coast of Yemen across the water to the north and defining the south coast of the Gulf of Aden. The Somali coast then takes a hairpin turn back southwest to complete the horn of Africa. For six months of the year the monsoon winds blow from up equatorial Somalia, past Arabia and over the small Yemeni archipelago of Socotra, to rain on India. They then switch directions and blow back. The east- and especially southeast-coast boundary of Arab Africa has historically been a gateway for maritime trade and cultural exchange with both East Africa and the subcontinent. The trade winds help explain the presence of the Comoros islands, an Arab-African country, off the coast of Mozambique, near Madagascar in the Indian Ocean, the southernmost part of the Arab World.[citation needed] The southern boundary of Arab North Africa is the strip of scrubland known as the Sahel that crosses the continent south of the Sahara.[citation needed] States and territories For the states and territories constituting the Arab world, see definition above. Different forms of government are represented in the Arab World: Some of the countries are monarchies: Bahrain, Jordan, Kuwait, Morocco, Oman, Qatar, Saudi Arabia and the United Arab Emirates. The other Arab countries are all republics. With the exception of Lebanon, Tunisia, Iraq, Palestine, and recently[when?] Mauritania, democratic elections throughout the Arab World are generally viewed as compromised, due to outright vote rigging, intimidation of opposition parties, and severe restraints on civil liberties and political dissent. After World War II, Pan-Arabism sought to unite all Arabic-speaking countries into one political entity. Only Syria, Iraq, Egypt, Sudan, Tunisia, Libya and North Yemen considered the short-lived unification of the United Arab Republic. Historical divisions, competing local nationalisms, and geographical sprawl were major reasons for the failure of Pan-Arabism. Arab Nationalism was another strong force in the region which peaked during the mid-20th century and was professed by many leaders in Egypt, Algeria, Libya, Syria, and Iraq. Arab Nationalist leaders of this period included Gamal Abdel Nasser of Egypt, Ahmed Ben Bella of Algeria, Michel Aflaq, Salah al-Din al-Bitar, Zaki al-Arsuzi, Constantin Zureiq and Shukri al-Kuwatli of Syria, Ahmed Hassan al-Bakr of Iraq, Habib Bourguiba of Tunisia, Mehdi Ben Barka of Morocco, and Shakib Arslan of Lebanon. Later and current Arab Nationalist leaders include Muammar al-Gaddafi of Libya, Hafez al-Assad and Bashar al-Assad of Syria. The diverse Arab states generally maintained close ties but distinct national identities developed and strengthened with the social, historical and political realities of the past 60 years. This has made the idea of a pan-Arab nation-state increasingly less feasible and likely. Additionally, an upsurge in political Islam has since led to a greater emphasis on pan-Islamic rather than pan-Arab identity amongst some Arab Muslims. Arab nationalists who once opposed Islamic movements as a threat to their power, now deal with them differently for reasons of political reality. Many of the modern borders of the Arab World were drawn by European imperial powers during the 19th and early 20th century. However, some of the larger states (in particular Egypt and Syria) have historically maintained geographically definable boundaries, on which some of the modern states are roughly based. The 14th-century Egyptian historian Al-Maqrizi, for instance, defines Egypt's boundaries as extending from the Mediterranean in the north to lower Nubia in the south; and between the Red Sea in the east and the oases of the Western/Libyan Desert. The modern borders of Egypt, therefore, are not a creation of European powers, and are at least in part based on historically definable entities which are in turn based on certain cultural and ethnic identifications. At other times, kings, emirs or sheikhs were placed as semi-autonomous rulers over the newly created nation states, usually chosen by the same imperial powers that for some drew the new borders, for services rendered to European powers like the British Empire, e.g. Sherif Hussein ibn Ali. Many African states did not attain independence until the 1960s from France after bloody insurgencies for their freedom. These struggles were settled by the imperial powers approving the form of independence given, so as a consequence almost all of these borders have remained. Some of these borders were agreed upon without consultation of those individuals that had served the colonial interests of Britain or France. One such agreement solely between Britain and France (to the exclusion of Sherif Hussein ibn Ali), signed in total secrecy until Lenin released the full text, was the Sykes-Picot Agreement. Another influential document written without the consensus of the local population was the Balfour Declaration. As former director of the Israeli intelligence agency Mossad, Efraim Halevy, now a director at the Hebrew University said, The borders, which if you look on the maps of the middle-east are very straight lines, were drawn by British and French draftsmen who sat with maps and drew the lines of the frontiers with rulers. If the ruler for some reason or other moved on the map, because of some person's hand shaking, then the frontier moved (with the hand). He went on to give an example, There was a famous story about a British consul, a lady named Gertrude Bell who drew the map between Iraq and Jordan, using transparent paper. She turned to talk to somebody and as she was turning the paper moved and the ruler moved and that added considerable territory to the (new) Jordanians. Historian Jim Crow, of Newcastle University, has said: Without that imperial carve-up, Iraq would not be in the state it is in today...Gertrude Bell was one of two or three Britons who were instrumental in the creation of the Arab states in the Middle East that were favourable to Britain. As of 2006, the Arab world accounts for two-fifths of the gross domestic product and three-fifths of the trade of the wider Muslim world.[citation needed] The Arab states are mostly, although not exclusively, developing economies and derive their export revenues from oil and gas, or the sale of other raw materials. Recent years have seen significant economic growth in the Arab World, due largely to an increase in oil and gas prices, which tripled between 2001 and 2006, but also due to efforts by some states to diversify their economic base. Industrial production has risen, for example the amount of steel produced between 2004 and 2005 rose from 8.4 to 19 million tonnes. (Source: Opening speech of Mahmoud Khoudri, Algeria's Industry Minister, at the 37th General Assembly of the Iron & Steel Arab Union, Algiers, May 2006). However even 19 million tons pa still only represents 1.7% of global steel production, and remains inferior to the production of countries like Brazil. The main economic organisations in the Arab World are the Gulf Cooperation Council (GCC), comprising the states in the Persian Gulf, and the Union of the Arab Maghreb (UMA), made up of North African States. The GCC has achieved some success in financial and monetary terms, including plans to establish a common currency in the Persian Gulf region. Since its foundation in 1989, the UMA's most significant accomplishment has been the establishment of a 7,000 km highway crossing North Africa from Mauritania to Libya's border with Egypt. The central stretch of the highway, expected to be completed in 2010, will cross Morocco, Algeria and Tunisia. In recent years a new term has been coined to define a greater economic region: the MENA region, standing for "Middle East and North Africa", is becoming increasingly popular, especially with support from the current US administration. As of August 2009 it was reported that Saudi Arabia is the strongest Arab economy according to World Bank. Saudi Arabia remains the top Arab economy in terms of total GDP. It is Asia's eleventh largest economy, followed by Egypt and Algeria, which were the second and third largest economies in Africa, after South Africa, in 2006. In terms of GDP per capita, Qatar is the richest developing country in the world. The total GDP of all Arab countries in 1999 was US$531.2 billion. The total Arab world GDP was estimated to be worth at least $2.8 trillion in 2011. This is only smaller than the GDP of the US, China, Japan and Germany. Demographics In the Arab world, Modern Standard Arabic, derived from Classical Arabic (symptomatic of Arabic diglossia), serves as an official language in the Arab League states, and Arabic dialects are used as lingua franca. Various indigenous languages are also spoken, which predate the spread of the Arabic language. This contrasts with the situation in the wider Islamic world, where, in contiguous Iran, Pakistan and Afghanistan, the Perso-Arabic script is used and Arabic is the primary liturgical language, but the tongue is not official at the state level or spoken as a vernacular. Arabs constitute around one quarter of the 1.5 billion Muslims in the Islamic world. Table of largest cities in the Arab world by official city propers: The majority of people in the Arab world adhere to Islam, and the religion has official status in most countries. Shariah law exists partially in the legal system in some countries (especially in the Arabian Peninsula), while others are legislatively secular. The majority of the Arab countries adhere to Sunni Islam. Iraq and Bahrain, however, are Shia majority countries, while Lebanon, Yemen, and Kuwait have large Shia minorities. In Saudi Arabia, Ismailite pockets are also found in the eastern Al-Hasa region and the southern city of Najran. Ibadi Islam is practiced in Oman, where Ibadis constitute around 75% of Muslims. There are also Christian adherents in the Arab world, particularly in Egypt, Syria, Lebanon, Iraq, Jordan, and Palestine. Small native Christian communities can be found also throughout the Arabian Peninsula and North Africa. Coptic, Maronite and Assyrian Christian enclaves exist in the Nile Valley, Levant and northern Iraq respectively. There are also Assyrian, Armenian and Arab Christians throughout Iraq, Syria, Palestine, Lebanon and Jordan, with Aramean communities in Maaloula and Jubb'adin in Syria. There are also native Arab Christian communities in Algeria, Bahrain, Morocco, Kuwait and Tunisia. Smaller ethno-religious minorities across the Arab League include the Yezidis, Yarsan and Shabaks (mainly in Iraq), the Druzes (mainly in Syria and also in Lebanon, Jordan) and Mandaeans (in Iraq). Formerly, there were significant minorities of Jews throughout the Arab World. However, the Arab–Israeli conflict prompted their mass exodus between 1948 and 1972. Today small Jewish communities remain, ranging anywhere from just 10 in Bahrain, to more than 400 in Iraq and Syria, 1,000 in Tunisia and some 3,000 in Morocco. According to UNESCO, the average rate of adult literacy (ages 15 and older) in this region is 78%. In Mauritania the rate is lower than the average, at less than 50%. Bahrain, Palestine, Kuwait, Qatar, and Jordan record a high adult literacy rate of over 95%. The average rate of adult literacy shows steady improvement, and the absolute number of adult illiterates fell from 64 million to around 58 million between 1990 and 2000–2004. Overall, the gender disparity in adult literacy is high in this region, and of the illiteracy rate, women account for two-thirds, with only 69 literate women for every 100 literate men. The average GPI (Gender Parity Index) for adult literacy is 0.72, and gender disparity can be observed in Egypt, Morocco, and Yemen. Above all, the GPI of Yemen is only 0.46 in a 53% adult literacy rate. Literacy rate is higher among the youth than adults. Youth literacy rate (ages 15–24) in the Arab region increased from 63.9 to 76.3% from 1990 to 2002. The average rate of GCC states was 94%, followed by the Maghreb at 83.2% and the Mashriq at 73.6%. The United Nations published an Arab human development report in 2002, 2003 and 2004. These reports, written by researchers from the Arab world, address some sensitive issues in the development of Arab countries: women empowerment, availability of education and information among others. Women in the Arab world are still denied equality of opportunity, although their disenfranchisement is a critical factor crippling the Arab nations' quest to return to the first rank of global leaders in commerce, learning and culture, according to a United Nations-sponsored report in 2008. There is no single description of Arab cinema since it includes films from various countries and cultures of the Arab world and therefore does not have one form, structure, or style. In its inception, Arab cinema was mostly an imitation of Western cinema. However, it has and continues to constantly change and evolve. It mostly includes films made in Egypt, Lebanon, Syria, Iraq, Kuwait, Algeria, Morocco, and Tunisia. Egypt is a pioneer in the field, but each country in the region has its own unique cinema. Elsewhere in North Africa and the Middle East, film production was scarce until the late 1960s and early 1970s when filmmakers began to receive funding and financial assistance from state organizations. This was during the post-independence and is when most Arab cinema took root. Most films produced at that time were funded by the state and contained a nationalistic dimension. These films helped to advance certain social causes such as independence, and other social, economic and political agendas. A sustained film industry was able to emerge in Egypt when other parts of the Arab world had only been able to sporadically produce feature-length films due to limited financing. Arabic cinema is dominated by films from Egypt. Three quarters of all Arab movies are produced in Egypt. According to film critic and historian Roy Armes, the cinema of Lebanon is the only other in the Arabic-speaking region, beside Egypt's, that could amount to a national cinema. While Egyptian and Lebanese cinema have a long history of production, most other Arab countries did not witness film production until after independence, and even today, the majority of film production in countries like Bahrain, Libya, Saudi Arabia, Sudan, and the United Arab Emirates is limited to television or short films. There is increased interest in films originating in the Arab world. For example, films from Algeria, Lebanon, Morocco, Palestine, Syria and Tunisia are making wider and more frequent rounds than ever before in local film festivals and repertoire theaters. Arab cinema has explored many topics from politics, colonialism, tradition, modernity and social taboos. It has also attempted to escape from its earlier tendency to mimic and rely on Western film devices. In fact, colonization did not only influence Arab films, but it also had an impact on Arab movies theaters. Apart from the history of Arab cinema, recently the portrayal of women became an important aspect in the production of Arab cinema. Arab women shaped a great portion of the film industry in the Arab world by employing their cinematic talents in improving the production of Arab films. The production of Arab cinema has declined in the last decades and many filmmakers in the Middle East gathered to hold a meeting and discuss the current state of Arab cinema. See also Notes References Sources Further reading External links |
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Contents Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", for its orange-red appearance. Mars is a desert-like rocky planet with a tenuous atmosphere that is primarily carbon dioxide (CO2). At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from −153 to 20 °C (−243 to 68 °F), and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, fog, frost, larger polar regions of permafrost and ice caps (with seasonal CO2 snow), but no bodies of liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. Its diameter, 6,779 km (4,212 mi), is about half the Earth's, or twice the Moon's, and its surface area is the size of all the dry land of Earth. Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south divide, the Martian dichotomy, with the northern hemisphere mainly consisting of relatively flat, low lying plains, and the southern hemisphere of cratered highlands. Geologically, the planet is fairly active with marsquakes trembling underneath the ground, but also hosts many enormous volcanoes that are extinct (the tallest is Olympus Mons, 21.9 km or 13.6 mi tall), as well as one of the largest canyons in the Solar System (Valles Marineris, 4,000 km or 2,500 mi long). Mars has two natural satellites that are small and irregular in shape: Phobos and Deimos. With a significant axial tilt of 25 degrees, Mars experiences seasons, like Earth (which has an axial tilt of 23.5 degrees). A Martian solar year is equal to 1.88 Earth years (687 Earth days), a Martian solar day (sol) is equal to 24.6 hours. Mars formed along with the other planets approximately 4.5 billion years ago. During the martian Noachian period (4.5 to 3.5 billion years ago), its surface was marked by meteor impacts, valley formation, erosion, the possible presence of water oceans and the loss of its magnetosphere. The Hesperian period (beginning 3.5 billion years ago and ending 3.3–2.9 billion years ago) was dominated by widespread volcanic activity and flooding that carved immense outflow channels. The Amazonian period, which continues to the present, is the currently dominating and remaining influence on geological processes. Because of Mars's geological history, the possibility of past or present life on Mars remains an area of active scientific investigation, with some possible traces needing further examination. Being visible with the naked eye in Earth's sky as a red wandering star, Mars has been observed throughout history, acquiring diverse associations in different cultures. In 1963 the first flight to Mars took place with Mars 1, but communication was lost en route. The first successful flyby exploration of Mars was conducted in 1965 with Mariner 4. In 1971 Mariner 9 entered orbit around Mars, being the first spacecraft to orbit any body other than the Moon, Sun or Earth; following in the same year were the first uncontrolled impact (Mars 2) and first successful landing (Mars 3) on Mars. Probes have been active on Mars continuously since 1997. At times, more than ten probes have simultaneously operated in orbit or on the surface, more than at any other planet beyond Earth. Mars is an often proposed target for future crewed exploration missions, though no such mission is currently planned. Natural history Scientists have theorized that during the Solar System's formation, Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine, phosphorus, and sulfur, are much more common on Mars than on Earth; these elements were probably pushed outward by the young Sun's energetic solar wind. After the formation of the planets, the inner Solar System may have been subjected to the so-called Late Heavy Bombardment. About 60% of the surface of Mars shows a record of impacts from that era, whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. However, more recent modeling has disputed the existence of the Late Heavy Bombardment. There is evidence of an enormous impact basin in the Northern Hemisphere of Mars, spanning 10,600 by 8,500 kilometres (6,600 by 5,300 mi), or roughly four times the size of the Moon's South Pole–Aitken basin, which would be the largest impact basin yet discovered if confirmed. It has been hypothesized that the basin was formed when Mars was struck by a Pluto-sized body about four billion years ago. The event, thought to be the cause of the Martian hemispheric dichotomy, created the smooth Borealis basin that covers 40% of the planet. A 2023 study shows evidence, based on the orbital inclination of Deimos (a small moon of Mars), that Mars may once have had a ring system 3.5 billion years to 4 billion years ago. This ring system may have been formed from a moon, 20 times more massive than Phobos, orbiting Mars billions of years ago; and Phobos would be a remnant of that ring. Epochs: The geological history of Mars can be split into many periods, but the following are the three primary periods: Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200 million years ago. Water flows in the grabens called the Cerberus Fossae occurred less than 20 million years ago, indicating equally recent volcanic intrusions. The Mars Reconnaissance Orbiter has captured images of avalanches. Physical characteristics Mars is approximately half the diameter of Earth or twice that of the Moon, with a surface area only slightly less than the total area of Earth's dry land. Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity. Mars is the only presently known example of a desert planet, a rocky planet with a surface akin to that of Earth's deserts. The red-orange appearance of the Martian surface is caused by iron(III) oxide (nanophase Fe2O3) and the iron(III) oxide-hydroxide mineral goethite. It can look like butterscotch; other common surface colors include golden, brown, tan, and greenish, depending on the minerals present. Like Earth, Mars is differentiated into a dense metallic core overlaid by less dense rocky layers. The outermost layer is the crust, which is on average about 42–56 kilometres (26–35 mi) thick, with a minimum thickness of 6 kilometres (3.7 mi) in Isidis Planitia, and a maximum thickness of 117 kilometres (73 mi) in the southern Tharsis plateau. For comparison, Earth's crust averages 27.3 ± 4.8 km in thickness. The most abundant elements in the Martian crust are silicon, oxygen, iron, magnesium, aluminum, calcium, and potassium. Mars is confirmed to be seismically active; in 2019, it was reported that InSight had detected and recorded over 450 marsquakes and related events. Beneath the crust is a silicate mantle responsible for many of the tectonic and volcanic features on the planet's surface. The upper Martian mantle is a low-velocity zone, where the velocity of seismic waves is lower than surrounding depth intervals. The mantle appears to be rigid down to the depth of about 250 km, giving Mars a very thick lithosphere compared to Earth. Below this the mantle gradually becomes more ductile, and the seismic wave velocity starts to grow again. The Martian mantle does not appear to have a thermally insulating layer analogous to Earth's lower mantle; instead, below 1050 km in depth, it becomes mineralogically similar to Earth's transition zone. At the bottom of the mantle lies a basal liquid silicate layer approximately 150–180 km thick. The Martian mantle appears to be highly heterogenous, with dense fragments up to 4 km across, likely injected deep into the planet by colossal impacts ~4.5 billion years ago; high-frequency waves from eight marsquakes slowed as they passed these localized regions, and modeling indicates the heterogeneities are compositionally distinct debris preserved because Mars lacks plate tectonics and has a sluggishly convecting interior that prevents complete homogenization. Mars's iron and nickel core is at least partially molten, and may have a solid inner core. It is around half of Mars's radius, approximately 1650–1675 km, and is enriched in light elements such as sulfur, oxygen, carbon, and hydrogen. The temperature of the core is estimated to be 2000–2400 K, compared to 5400–6230 K for Earth's solid inner core. In 2025, based on data from the InSight lander, a group of researchers reported the detection of a solid inner core 613 kilometres (381 mi) ± 67 kilometres (42 mi) in radius. Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The Martian surface is primarily composed of tholeiitic basalt, although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth, or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have been found. Much of the surface is deeply covered by finely grained iron(III) oxide dust. The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in soils on Earth, and are necessary for plant growth. Experiments performed by the lander showed that the Martian soil has a basic pH of 7.7, and contains 0.6% perchlorate by weight, concentrations that are toxic to humans. Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted hypotheses include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils. Several other explanations have been put forward, including those that involve water or even the growth of organisms. Environmental radiation levels on the surface are on average 0.64 millisieverts of radiation per day, and significantly less than the radiation of 1.84 millisieverts per day or 22 millirads per day during the flight to and from Mars. For comparison the radiation levels in low Earth orbit, where Earth's space stations orbit, are around 0.5 millisieverts of radiation per day. Hellas Planitia has the lowest surface radiation at about 0.342 millisieverts per day, featuring lava tubes southwest of Hadriacus Mons with potentially levels as low as 0.064 millisieverts per day, comparable to radiation levels during flights on Earth. Although Mars has no evidence of a structured global magnetic field, observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors. One hypothesis, published in 1999 and re-examined in October 2005 (with the help of the Mars Global Surveyor), is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded. Geography and features Although better remembered for mapping the Moon, Johann Heinrich von Mädler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mädler combined ten years of observations and drew the first map of Mars. Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50 km are named for deceased scientists and writers and others who have contributed to the study of Mars. Smaller craters are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; smaller valleys are named for rivers. Large albedo features retain many of the older names but are often updated to reflect new knowledge of the nature of the features. For example, Nix Olympica (the snows of Olympus) has become Olympus Mons (Mount Olympus). The surface of Mars as seen from Earth is divided into two kinds of areas, with differing albedo. The paler plains covered with dust and sand rich in reddish iron oxides were once thought of as Martian "continents" and given names like Arabia Terra (land of Arabia) or Amazonis Planitia (Amazonian plain). The dark features were thought to be seas, hence their names Mare Erythraeum, Mare Sirenum and Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major Planum. The permanent northern polar ice cap is named Planum Boreum. The southern cap is called Planum Australe. Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft Mariner 9 provided extensive imagery of Mars in 1972, a small crater (later called Airy-0), located in the Sinus Meridiani ("Middle Bay" or "Meridian Bay"), was chosen by Merton E. Davies, Harold Masursky, and Gérard de Vaucouleurs for the definition of 0.0° longitude to coincide with the original selection. Because Mars has no oceans, and hence no "sea level", a zero-elevation surface had to be selected as a reference level; this is called the areoid of Mars, analogous to the terrestrial geoid. Zero altitude was defined by the height at which there is 610.5 Pa (6.105 mbar) of atmospheric pressure. This pressure corresponds to the triple point of water, and it is about 0.6% of the sea level surface pressure on Earth (0.006 atm). For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles, each named for a classical albedo feature it contains. In April 2023, The New York Times reported an updated global map of Mars based on images from the Hope spacecraft. A related, but much more detailed, global Mars map was released by NASA on 16 April 2023. The vast upland region Tharsis contains several massive volcanoes, which include the shield volcano Olympus Mons. The edifice is over 600 km (370 mi) wide. Because the mountain is so large, with complex structure at its edges, giving a definite height to it is difficult. Its local relief, from the foot of the cliffs which form its northwest margin to its peak, is over 21 km (13 mi), a little over twice the height of Mauna Kea as measured from its base on the ocean floor. The total elevation change from the plains of Amazonis Planitia, over 1,000 km (620 mi) to the northwest, to the summit approaches 26 km (16 mi), roughly three times the height of Mount Everest, which in comparison stands at just over 8.8 kilometres (5.5 mi). Consequently, Olympus Mons is either the tallest or second-tallest mountain in the Solar System; the only known mountain which might be taller is the Rheasilvia peak on the asteroid Vesta, at 20–25 km (12–16 mi). The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon. If this is the case, the Northern Hemisphere of Mars would be the site of an impact crater 10,600 by 8,500 kilometres (6,600 by 5,300 mi) in size, or roughly the area of Europe, Asia, and Australia combined, surpassing Utopia Planitia and the Moon's South Pole–Aitken basin as the largest impact crater in the Solar System. Mars is scarred by 43,000 impact craters with a diameter of 5 kilometres (3.1 mi) or greater. The largest exposed crater is Hellas, which is 2,300 kilometres (1,400 mi) wide and 7,000 metres (23,000 ft) deep, and is a light albedo feature clearly visible from Earth. There are other notable impact features, such as Argyre, which is around 1,800 kilometres (1,100 mi) in diameter, and Isidis, which is around 1,500 kilometres (930 mi) in diameter. Due to the smaller mass and size of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, i.e., those that lie within the orbit of Jupiter. Martian craters can[discuss] have a morphology that suggests the ground became wet after the meteor impact. The large canyon, Valles Marineris (Latin for 'Mariner Valleys, also known as Agathodaemon in the old canal maps), has a length of 4,000 kilometres (2,500 mi) and a depth of up to 7 kilometres (4.3 mi). The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only 446 kilometres (277 mi) long and nearly 2 kilometres (1.2 mi) deep. Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where 150 kilometres (93 mi) of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement. Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from 100 to 252 metres (328 to 827 ft) wide and they are estimated to be at least 73 to 96 metres (240 to 315 ft) deep. Because light does not reach the floor of most of the caves, they may extend much deeper than these lower estimates and widen below the surface. "Dena" is the only exception; its floor is visible and was measured to be 130 metres (430 ft) deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface. Martian geysers (or CO2 jets) are putative sites of small gas and dust eruptions that occur in the south polar region of Mars during the spring thaw. "Dark dune spots" and "spiders" – or araneiforms – are the two most visible types of features ascribed to these eruptions. Similarly sized dust will settle from the thinner Martian atmosphere sooner than it would on Earth. For example, the dust suspended by the 2001 global dust storms on Mars only remained in the Martian atmosphere for 0.6 years, while the dust from Mount Pinatubo took about two years to settle. However, under current Martian conditions, the mass movements involved are generally much smaller than on Earth. Even the 2001 global dust storms on Mars moved only the equivalent of a very thin dust layer – about 3 μm thick if deposited with uniform thickness between 58° north and south of the equator. Dust deposition at the two rover sites has proceeded at a rate of about the thickness of a grain every 100 sols. Atmosphere Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. Both Mars Global Surveyor and Mars Express have detected ionized atmospheric particles trailing off into space behind Mars, and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from a low of 30 Pa (0.0044 psi) on Olympus Mons to over 1,155 Pa (0.1675 psi) in Hellas Planitia, with a mean pressure at the surface level of 600 Pa (0.087 psi). The highest atmospheric density on Mars is equal to that found 35 kilometres (22 mi) above Earth's surface. The resulting mean surface pressure is only 0.6% of Earth's 101.3 kPa (14.69 psi). The scale height of the atmosphere is about 10.8 kilometres (6.7 mi), which is higher than Earth's 6 kilometres (3.7 mi), because the surface gravity of Mars is only about 38% of Earth's. The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates about 1.5 μm in diameter which give the Martian sky a tawny color when seen from the surface. It may take on a pink hue due to iron oxide particles suspended in it. Despite repeated detections of methane on Mars, there is no scientific consensus as to its origin. One suggestion is that methane exists on Mars and that its concentration fluctuates seasonally. The existence of methane could be produced by non-biological process such as serpentinization involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars, or by Martian life. Compared to Earth, its higher concentration of atmospheric CO2 and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the Perseverance rover, researchers concluded that the speed of sound there is approximately 240 m/s for frequencies below 240 Hz, and 250 m/s for those above. Auroras have been detected on Mars. Because Mars lacks a global magnetic field, the types and distribution of auroras there differ from those on Earth; rather than being mostly restricted to polar regions as is the case on Earth, a Martian aurora can encompass the planet. In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25 times brighter than any observed earlier, due to a massive, and unexpected, solar storm in the middle of the month. Mars has seasons, alternating between its northern and southern hemispheres, similar to on Earth. Additionally the orbit of Mars has, compared to Earth's, a large eccentricity and approaches perihelion when it is summer in its southern hemisphere and winter in its northern, and aphelion when it is winter in its southern hemisphere and summer in its northern. As a result, the seasons in its southern hemisphere are more extreme and the seasons in its northern are milder than would otherwise be the case. The summer temperatures in the south can be warmer than the equivalent summer temperatures in the north by up to 30 °C (54 °F). Martian surface temperatures vary from lows of about −110 °C (−166 °F) to highs of up to 35 °C (95 °F) in equatorial summer. The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure (about 1% that of the atmosphere of Earth), and the low thermal inertia of Martian soil. The planet is 1.52 times as far from the Sun as Earth, resulting in just 43% of the amount of sunlight. Mars has the largest dust storms in the Solar System, reaching speeds of over 160 km/h (100 mph). These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase global temperature. Seasons also produce dry ice covering polar ice caps. Hydrology While Mars contains water in larger amounts, most of it is dust covered water ice at the Martian polar ice caps. The volume of water ice in the south polar ice cap, if melted, would be enough to cover most of the surface of the planet with a depth of 11 metres (36 ft). Water in its liquid form cannot persist on the surface due to Mars's low atmospheric pressure, which is less than 1% that of Earth. Only at the lowest of elevations are the pressure and temperature high enough for liquid water to exist for short periods. Although little water is present in the atmosphere, there is enough to produce clouds of water ice and different cases of snow and frost, often mixed with snow of carbon dioxide dry ice. Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels, cut across the surface in about 25 places. These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers, though some of these structures have been hypothesized to result from the action of glaciers or lava. One of the larger examples, Ma'adim Vallis, is 700 kilometres (430 mi) long, much greater than the Grand Canyon, with a width of 20 kilometres (12 mi) and a depth of 2 kilometres (1.2 mi) in places. It is thought to have been carved by flowing water early in Mars's history. The youngest of these channels is thought to have formed only a few million years ago. Elsewhere, particularly on the oldest areas of the Martian surface, finer-scale, dendritic networks of valleys are spread across significant proportions of the landscape. Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history. Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks, but precipitation was probably the root cause of the incision in almost all cases. Along craters and canyon walls, there are thousands of features that appear similar to terrestrial gullies. The gullies tend to be in the highlands of the Southern Hemisphere and face the Equator; all are poleward of 30° latitude. A number of authors have suggested that their formation process involves liquid water, probably from melting ice, although others have argued for formation mechanisms involving carbon dioxide frost or the movement of dry dust. No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed, indicating that these are young features, possibly still active. Other geological features, such as deltas and alluvial fans preserved in craters, are further evidence for warmer, wetter conditions at an interval or intervals in earlier Mars history. Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface, for which there is independent mineralogical, sedimentological and geomorphological evidence. Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water. The chemical signature of water vapor on Mars was first unequivocally demonstrated in 1963 by spectroscopy using an Earth-based telescope. In 2004, Opportunity detected the mineral jarosite. This forms only in the presence of acidic water, showing that water once existed on Mars. The Spirit rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum, which also forms in the presence of water, was found on the surface by NASA's Mars rover Opportunity. It is estimated that the amount of water in the upper mantle of Mars, represented by hydroxyl ions contained within Martian minerals, is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200–1,000 metres (660–3,280 ft). On 18 March 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock. Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 centimetres (24 in), during the rover's traverse from the Bradbury Landing site to the Yellowknife Bay area in the Glenelg terrain. In September 2015, NASA announced that they had found strong evidence of hydrated brine flows in recurring slope lineae, based on spectrometer readings of the darkened areas of slopes. These streaks flow downhill in Martian summer, when the temperature is above −23 °C, and freeze at lower temperatures. These observations supported earlier hypotheses, based on timing of formation and their rate of growth, that these dark streaks resulted from water flowing just below the surface. However, later work suggested that the lineae may be dry, granular flows instead, with at most a limited role for water in initiating the process. A definitive conclusion about the presence, extent, and role of liquid water on the Martian surface remains elusive. Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial. In March 2015, scientists stated that such an ocean might have been the size of Earth's Arctic Ocean. This finding was derived from the ratio of protium to deuterium in the modern Martian atmosphere compared to that ratio on Earth. The amount of Martian deuterium (D/H = 9.3 ± 1.7 10−4) is five to seven times the amount on Earth (D/H = 1.56 10−4), suggesting that ancient Mars had significantly higher levels of water. Results from the Curiosity rover had previously found a high ratio of deuterium in Gale Crater, though not significantly high enough to suggest the former presence of an ocean. Other scientists caution that these results have not been confirmed, and point out that Martian climate models have not yet shown that the planet was warm enough in the past to support bodies of liquid water. Near the northern polar cap is the 81.4 kilometres (50.6 mi) wide Korolev Crater, which the Mars Express orbiter found to be filled with approximately 2,200 cubic kilometres (530 cu mi) of water ice. In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior (which is 12,100 cubic kilometers). During observations from 2018 through 2021, the ExoMars Trace Gas Orbiter spotted indications of water, probably subsurface ice, in the Valles Marineris canyon system. Orbital motion Mars's average distance from the Sun is roughly 230 million km (143 million mi), and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. The gravitational potential difference and thus the delta-v needed to transfer between Mars and Earth is the second lowest for Earth. The axial tilt of Mars is 25.19° relative to its orbital plane, which is similar to the axial tilt of Earth. As a result, Mars has seasons like Earth, though on Mars they are nearly twice as long because its orbital period is that much longer. In the present day, the orientation of the north pole of Mars is close to the star Deneb. Mars has a relatively pronounced orbital eccentricity of about 0.09; of the seven other planets in the Solar System, only Mercury has a larger orbital eccentricity. It is known that in the past, Mars has had a much more circular orbit. At one point, 1.35 million Earth years ago, Mars had an eccentricity of roughly 0.002, much less than that of Earth today. Mars's cycle of eccentricity is 96,000 Earth years compared to Earth's cycle of 100,000 years. Mars has its closest approach to Earth (opposition) in a synodic period of 779.94 days. It should not be confused with Mars conjunction, where the Earth and Mars are at opposite sides of the Solar System and form a straight line crossing the Sun. The average time between the successive oppositions of Mars, its synodic period, is 780 days; but the number of days between successive oppositions can range from 764 to 812. The distance at close approach varies between about 54 and 103 million km (34 and 64 million mi) due to the planets' elliptical orbits, which causes comparable variation in angular size. At their furthest Mars and Earth can be as far as 401 million km (249 million mi) apart. Mars comes into opposition from Earth every 2.1 years. The planets come into opposition near Mars's perihelion in 2003, 2018 and 2035, with the 2020 and 2033 events being particularly close to perihelic opposition. The mean apparent magnitude of Mars is +0.71 with a standard deviation of 1.05. Because the orbit of Mars is eccentric, the magnitude at opposition from the Sun can range from about −3.0 to −1.4. The minimum brightness is magnitude +1.86 when the planet is near aphelion and in conjunction with the Sun. At its brightest, Mars (along with Jupiter) is second only to Venus in apparent brightness. Mars usually appears distinctly yellow, orange, or red. When farthest away from Earth, it is more than seven times farther away than when it is closest. Mars is usually close enough for particularly good viewing once or twice at 15-year or 17-year intervals. Optical ground-based telescopes are typically limited to resolving features about 300 kilometres (190 mi) across when Earth and Mars are closest because of Earth's atmosphere. As Mars approaches opposition, it begins a period of retrograde motion, which means it will appear to move backwards in a looping curve with respect to the background stars. This retrograde motion lasts for about 72 days, and Mars reaches its peak apparent brightness in the middle of this interval. Moons Mars has two relatively small (compared to Earth's) natural moons, Phobos (about 22 km (14 mi) in diameter) and Deimos (about 12 km (7.5 mi) in diameter), which orbit at 9,376 km (5,826 mi) and 23,460 km (14,580 mi) around the planet. The origin of both moons is unclear, although a popular theory states that they were asteroids captured into Martian orbit. Both satellites were discovered in 1877 by Asaph Hall and were named after the characters Phobos (the deity of panic and fear) and Deimos (the deity of terror and dread), twins from Greek mythology who accompanied their father Ares, god of war, into battle. Mars was the Roman equivalent to Ares. In modern Greek, the planet retains its ancient name Ares (Aris: Άρης). From the surface of Mars, the motions of Phobos and Deimos appear different from that of the Earth's satellite, the Moon. Phobos rises in the west, sets in the east, and rises again in just 11 hours. Deimos, being only just outside synchronous orbit – where the orbital period would match the planet's period of rotation – rises as expected in the east, but slowly. Because the orbit of Phobos is below a synchronous altitude, tidal forces from Mars are gradually lowering its orbit. In about 50 million years, it could either crash into Mars's surface or break up into a ring structure around the planet. The origin of the two satellites is not well understood. Their low albedo and carbonaceous chondrite composition have been regarded as similar to asteroids, supporting a capture theory. The unstable orbit of Phobos would seem to point toward a relatively recent capture. But both have circular orbits near the equator, which is unusual for captured objects, and the required capture dynamics are complex. Accretion early in the history of Mars is plausible, but would not account for a composition resembling asteroids rather than Mars itself, if that is confirmed. Mars may have yet-undiscovered moons, smaller than 50 to 100 metres (160 to 330 ft) in diameter, and a dust ring is predicted to exist between Phobos and Deimos. A third possibility for their origin as satellites of Mars is the involvement of a third body or a type of impact disruption. More-recent lines of evidence for Phobos having a highly porous interior, and suggesting a composition containing mainly phyllosilicates and other minerals known from Mars, point toward an origin of Phobos from material ejected by an impact on Mars that reaccreted in Martian orbit, similar to the prevailing theory for the origin of Earth's satellite. Although the visible and near-infrared (VNIR) spectra of the moons of Mars resemble those of outer-belt asteroids, the thermal infrared spectra of Phobos are reported to be inconsistent with chondrites of any class. It is also possible that Phobos and Deimos were fragments of an older moon, formed by debris from a large impact on Mars, and then destroyed by a more recent impact upon the satellite. More recently, a study conducted by a team of researchers from multiple countries suggests that a lost moon, at least fifteen times the size of Phobos, may have existed in the past. By analyzing rocks which point to tidal processes on the planet, it is possible that these tides may have been regulated by a past moon. Human observations and exploration The history of observations of Mars is marked by oppositions of Mars when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars, which are distinguished because Mars is close to perihelion, making it even closer to Earth. The ancient Sumerians named Mars Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh. In Mesopotamian texts, Mars is referred to as the "star of judgement of the fate of the dead". The existence of Mars as a wandering object in the night sky was also recorded by the ancient Egyptian astronomers and, by 1534 BCE, they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They invented arithmetic methods for making minor corrections to the predicted positions of the planets. In Ancient Greece, the planet was known as Πυρόεις. Commonly, the Greek name for the planet now referred to as Mars, was Ares. It was the Romans who named the planet Mars, for their god of war, often represented by the sword and shield of the planet's namesake. In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating that the planet was farther away. Ptolemy, a Greek living in Alexandria, attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented in the multi-volume collection later called the Almagest (from the Arabic for "greatest"), which became the authoritative treatise on Western astronomy for the next fourteen centuries. Literature from ancient China confirms that Mars was known by Chinese astronomers by no later than the fourth century BCE. In the East Asian cultures, Mars is traditionally referred to as the "fire star" (火星) based on the Wuxing system. In 1609 Johannes Kepler published a 10 year study of Martian orbit, using the diurnal parallax of Mars, measured by Tycho Brahe, to make a preliminary calculation of the relative distance to the planet. From Brahe's observations of Mars, Kepler deduced that the planet orbited the Sun not in a circle, but in an ellipse. Moreover, Kepler showed that Mars sped up as it approached the Sun and slowed down as it moved farther away, in a manner that later physicists would explain as a consequence of the conservation of angular momentum.: 433–437 In 1610 the first use of a telescope for astronomical observation, including Mars, was performed by Italian astronomer Galileo Galilei. With the telescope the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance. This was first performed by Giovanni Domenico Cassini in 1672. The early parallax measurements were hampered by the quality of the instruments. The only occultation of Mars by Venus observed was that of 13 October 1590, seen by Michael Maestlin at Heidelberg. By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. On 5 September 1877, a perihelic opposition to Mars occurred. The Italian astronomer Giovanni Schiaparelli used a 22-centimetre (8.7 in) telescope in Milan to help produce the first detailed map of Mars. These maps notably contained features he called canali, which, with the possible exception of the natural canyon Valles Marineris, were later shown to be an optical illusion. These canali were supposedly long, straight lines on the surface of Mars, to which he gave names of famous rivers on Earth. His term, which means "channels" or "grooves", was popularly mistranslated in English as "canals". Influenced by the observations, the orientalist Percival Lowell founded an observatory which had 30- and 45-centimetre (12- and 18-in) telescopes. The observatory was used for the exploration of Mars during the last good opportunity in 1894, and the following less favorable oppositions. He published several books on Mars and life on the planet, which had a great influence on the public. The canali were independently observed by other astronomers, like Henri Joseph Perrotin and Louis Thollon in Nice, using one of the largest telescopes of that time. The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summers) in combination with the canals led to speculation about life on Mars, and it was a long-held belief that Mars contained vast seas and vegetation. As bigger telescopes were used, fewer long, straight canali were observed. During observations in 1909 by Antoniadi with an 84-centimetre (33 in) telescope, irregular patterns were observed, but no canali were seen. The first spacecraft from Earth to visit Mars was Mars 1 of the Soviet Union, which flew by in 1963, but contact was lost en route. NASA's Mariner 4 followed and became the first spacecraft to successfully transmit from Mars; launched on 28 November 1964, it made its closest approach to the planet on 15 July 1965. Mariner 4 detected the weak Martian radiation belt, measured at about 0.1% that of Earth, and captured the first images of another planet from deep space. Once spacecraft visited the planet during the 1960s and 1970s, many previous concepts of Mars were radically broken. After the results of the Viking life-detection experiments, the hypothesis of a dead planet was generally accepted. The data from Mariner 9 and Viking allowed better maps of Mars to be made. Until 1997 and after Viking 1 shut down in 1982, Mars was only visited by three unsuccessful probes, two flying past without contact (Phobos 1, 1988; Mars Observer, 1993), and one (Phobos 2 1989) malfunctioning in orbit before reaching its destination Phobos. In 1997 Mars Pathfinder became the first successful rover mission beyond the Moon and started together with Mars Global Surveyor (operated until late 2006) an uninterrupted active robotic presence at Mars that has lasted until today. It produced complete, extremely detailed maps of the Martian topography, magnetic field and surface minerals. Starting with these missions a range of new improved crewless spacecraft, including orbiters, landers, and rovers, have been sent to Mars, with successful missions by the NASA (United States), Jaxa (Japan), ESA, United Kingdom, ISRO (India), Roscosmos (Russia), the United Arab Emirates, and CNSA (China) to study the planet's surface, climate, and geology, uncovering the different elements of the history and dynamic of the hydrosphere of Mars and possible traces of ancient life. As of 2023[update], Mars is host to ten functioning spacecraft. Eight are in orbit: 2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN, ExoMars Trace Gas Orbiter, the Hope orbiter, and the Tianwen-1 orbiter. Another two are on the surface: the Mars Science Laboratory Curiosity rover and the Perseverance rover. Collected maps are available online at websites including Google Mars. NASA provides two online tools: Mars Trek, which provides visualizations of the planet using data from 50 years of exploration, and Experience Curiosity, which simulates traveling on Mars in 3-D with Curiosity. Planned missions to Mars include: As of February 2024[update], debris from these types of missions has reached over seven tons. Most of it consists of crashed and inactive spacecraft as well as discarded components. In April 2024, NASA selected several companies to begin studies on providing commercial services to further enable robotic science on Mars. Key areas include establishing telecommunications, payload delivery and surface imaging. Habitability and habitation During the late 19th century, it was widely accepted in the astronomical community that Mars had life-supporting qualities, including the presence of oxygen and water. However, in 1894 W. W. Campbell at Lick Observatory observed the planet and found that "if water vapor or oxygen occur in the atmosphere of Mars it is in quantities too small to be detected by spectroscopes then available". That observation contradicted many of the measurements of the time and was not widely accepted. Campbell and V. M. Slipher repeated the study in 1909 using better instruments, but with the same results. It was not until the findings were confirmed by W. S. Adams in 1925 that the myth of the Earth-like habitability of Mars was finally broken. However, even in the 1960s, articles were published on Martian biology, putting aside explanations other than life for the seasonal changes on Mars. The current understanding of planetary habitability – the ability of a world to develop environmental conditions favorable to the emergence of life – favors planets that have liquid water on their surface. Most often this requires the orbit of a planet to lie within the habitable zone, which for the Sun is estimated to extend from within the orbit of Earth to about that of Mars. During perihelion, Mars dips inside this region, but Mars's thin (low-pressure) atmosphere prevents liquid water from existing over large regions for extended periods. The past flow of liquid water demonstrates the planet's potential for habitability. Recent evidence has suggested that any water on the Martian surface may have been too salty and acidic to support regular terrestrial life. The environmental conditions on Mars are a challenge to sustaining organic life: the planet has little heat transfer across its surface, it has poor insulation against bombardment by the solar wind due to the absence of a magnetosphere and has insufficient atmospheric pressure to retain water in a liquid form (water instead sublimes to a gaseous state). Mars is nearly, or perhaps totally, geologically dead; the end of volcanic activity has apparently stopped the recycling of chemicals and minerals between the surface and interior of the planet. Evidence suggests that the planet was once significantly more habitable than it is today, but whether living organisms ever existed there remains unknown. The Viking probes of the mid-1970s carried experiments designed to detect microorganisms in Martian soil at their respective landing sites and had positive results, including a temporary increase in CO2 production on exposure to water and nutrients. This sign of life was later disputed by scientists, resulting in a continuing debate, with NASA scientist Gilbert Levin asserting that Viking may have found life. A 2014 analysis of Martian meteorite EETA79001 found chlorate, perchlorate, and nitrate ions in sufficiently high concentrations to suggest that they are widespread on Mars. UV and X-ray radiation would turn chlorate and perchlorate ions into other, highly reactive oxychlorines, indicating that any organic molecules would have to be buried under the surface to survive. Small quantities of methane and formaldehyde detected by Mars orbiters are both claimed to be possible evidence for life, as these chemical compounds would quickly break down in the Martian atmosphere. Alternatively, these compounds may instead be replenished by volcanic or other geological means, such as serpentinite. Impact glass, formed by the impact of meteors, which on Earth can preserve signs of life, has also been found on the surface of the impact craters on Mars. Likewise, the glass in impact craters on Mars could have preserved signs of life, if life existed at the site. The Cheyava Falls rock discovered on Mars in June 2024 has been designated by NASA as a "potential biosignature" and was core sampled by the Perseverance rover for possible return to Earth and further examination. Although highly intriguing, no definitive final determination on a biological or abiotic origin of this rock can be made with the data currently available. Several plans for a human mission to Mars have been proposed, but none have come to fruition. The NASA Authorization Act of 2017 directed NASA to study the feasibility of a crewed Mars mission in the early 2030s; the resulting report concluded that this would be unfeasible. In addition, in 2021, China was planning to send a crewed Mars mission in 2033. Privately held companies such as SpaceX have also proposed plans to send humans to Mars, with the eventual goal to settle on the planet. As of 2024, SpaceX has proceeded with the development of the Starship launch vehicle with the goal of Mars colonization. In plans shared with the company in April 2024, Elon Musk envisions the beginning of a Mars colony within the next twenty years. This would be enabled by the planned mass manufacturing of Starship and initially sustained by resupply from Earth, and in situ resource utilization on Mars, until the Mars colony reaches full self sustainability. Any future human mission to Mars will likely take place within the optimal Mars launch window, which occurs every 26 months. The moon Phobos has been proposed as an anchor point for a space elevator. Besides national space agencies and space companies, groups such as the Mars Society and The Planetary Society advocate for human missions to Mars. In culture Mars is named after the Roman god of war (Greek Ares), but was also associated with the demi-god Heracles (Roman Hercules) by ancient Greek astronomers, as detailed by Aristotle. This association between Mars and war dates back at least to Babylonian astronomy, in which the planet was named for the god Nergal, deity of war and destruction. It persisted into modern times, as exemplified by Gustav Holst's orchestral suite The Planets, whose famous first movement labels Mars "The Bringer of War". The planet's symbol, a circle with a spear pointing out to the upper right, is also used as a symbol for the male gender. The symbol dates from at least the 11th century, though a possible predecessor has been found in the Greek Oxyrhynchus Papyri. The idea that Mars was populated by intelligent Martians became widespread in the late 19th century. Schiaparelli's "canali" observations combined with Percival Lowell's books on the subject put forward the standard notion of a planet that was a drying, cooling, dying world with ancient civilizations constructing irrigation works. Many other observations and proclamations by notable personalities added to what has been termed "Mars Fever". In the present day, high-resolution mapping of the surface of Mars has revealed no artifacts of habitation, but pseudoscientific speculation about intelligent life on Mars still continues. Reminiscent of the canali observations, these speculations are based on small scale features perceived in the spacecraft images, such as "pyramids" and the "Face on Mars". In his book Cosmos, planetary astronomer Carl Sagan wrote: "Mars has become a kind of mythic arena onto which we have projected our Earthly hopes and fears." The depiction of Mars in fiction has been stimulated by its dramatic red color and by nineteenth-century scientific speculations that its surface conditions might support not just life but intelligent life. This gave way to many science fiction stories involving these concepts, such as H. G. Wells's The War of the Worlds, in which Martians seek to escape their dying planet by invading Earth; Ray Bradbury's The Martian Chronicles, in which human explorers accidentally destroy a Martian civilization; as well as Edgar Rice Burroughs's series Barsoom, C. S. Lewis's novel Out of the Silent Planet (1938), and a number of Robert A. Heinlein stories before the mid-sixties. Since then, depictions of Martians have also extended to animation. A comic figure of an intelligent Martian, Marvin the Martian, appeared in Haredevil Hare (1948) as a character in the Looney Tunes animated cartoons of Warner Brothers, and has continued as part of popular culture to the present. After the Mariner and Viking spacecraft had returned pictures of Mars as a lifeless and canal-less world, these ideas about Mars were abandoned; for many science-fiction authors, the new discoveries initially seemed like a constraint, but eventually the post-Viking knowledge of Mars became itself a source of inspiration for works like Kim Stanley Robinson's Mars trilogy. See also Notes References Further reading External links Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Local Sheet → Local Volume → Virgo Supercluster → Laniakea Supercluster → Pisces–Cetus Supercluster Complex → Local Hole → Observable universe → UniverseEach arrow (→) may be read as "within" or "part of". |
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[SOURCE: https://en.wikipedia.org/wiki/COMAL] | [TOKENS: 1462] |
Contents COMAL COMAL (Common Algorithmic Language) is a computer programming language developed in Denmark by Børge R. Christensen and Benedict Løfstedt and originally released in 1975. It was based on the BASIC programming language, adding multi-line statements and well-defined subroutines among other additions. COMAL was originally written for minicomputers, but was small enough to run on early microcomputers as well. It is one of the few structured programming languages that were available for and comfortably usable on 8-bit home computers. "COMAL Kernel Syntax & Semantics" contains the formal definition of the language. Further extensions are common to many implementations. History COMAL was originally developed in Denmark by mathematics teacher Børge R. Christensen. The school in which he taught had received a Data General Nova 1200 minicomputer in 1972, with the expectation that the school would begin to teach computer science. Christensen, who had taken a short course on the subject at university, was expected to lead the program and to maintain the computer system. The NOVA was supplied with Data General Extended BASIC, and Christensen quickly became frustrated with the way in which the unstructured language led students to write low-quality code that was difficult to read and thus mark. While complaining about these problems to computer scientist Benedict Løfstedt, Løfstedt encouraged Christensen to read Systematic Programming, the then-new book on programming language design by Niklaus Wirth, the creator of Pascal. Christensen was impressed, but found that he could not use Pascal directly, as it lacked the interactive shell that made BASIC so easy for students to develop with. Over the next six months Christensen and Løfstedt corresponded by mail to design an alternative to BASIC which retained its interactive elements but added structured elements from Pascal. By 1974, the language's definition was complete but Christensen was unsuccessful in attracting interest from software firms in developing an implementation. Over the next six months he worked with two of his students, to whom he had taught NOVA 1200 machine language, to write an implementation themselves. One of the first things added was the ability to use eight-character variable names, up from the typical one or two. Later additions in the first version included multi-line IF...THEN...ELSE...ENDIF statements, and the PROC...ENDPROC definitions and the EXECUTE statement to call them. The first proof-of-concept implementation (running a five-line loop) was ready on 5 August 1974, and the first release (on paper tape) was ready in February 1975. Development costs had been around US$300. Only now did the system (which had previously used an internal Danish name) pick up the name COMAL, for Common Algorithmic Language, inspired by ALGOL, with which Christensen had been experimenting. The first release was therefore named COMAL 75. Christensen subsequently wrote a textbook on the language which evolved into Beginning COMAL. In 1978, Christensen began to adapt COMAL such that it would run on microcomputers, which were becoming available. He was worried that without such an implementation he would be required to teach and use BASIC again as Danish schools acquired the new machines. By 1980, a version of COMAL developed in conjunction with a college group was able to run on the Zilog Z80, and thus COMAL 80 was released. Around the same time, a Danish firm introduced the Comet, a very capable microcomputer for the time, which would be the first machine to run a version of what would look like the later COMAL releases. Christensen subsequently stepped back from COMAL development around 1980-81, which was handed over to groups including UniComal, started by Mogens Kjaer, who had written to Christensen with critiques of COMAL and subsequently ported it to the Commodore PET for release 0.14. At this time, Danish schools insisted that COMAL be available on any microcomputer they purchased. In the early 1980s, Apple Computer won a contract to supply Apple II computers running CP/M and COMAL to Irish secondary schools. It was popular for education and some textbooks were locally written. In 1984, Acornsoft released a COMAL implementation, by David Christensen, Jim Warwick and David Evers, for their 8-bit BBC Micro and Acorn Electron computers (with a manual by Paul Christensen and Roy Thornton) Between 1984-1987, TeleNova, a subsidiary of the industrial arm of the Swedish Telecoms system, manufactured a desktop PC called "Compis" for the educational sector. An enhanced version of COMAL was supplied as the standard programming language for this PC. Versions were created for both CP/M-86 and MS-DOS. The latter version is available for Windows XP. The (Swedish) reference manual is ISBN 91-24-40022-X. In 1990, Thomas Lundy and Rory O'Sullivan produced the definitive text on COMAL Programming. They matched and compared COMAL with BBC Structured Basic. As of 2016, COMAL is still actively in use as an educational programming language. Some high schools in the United Kingdom continue to use it to teach the subject of computing. Description COMAL was created as a mixture of the prevalent educational programming languages of the time, BASIC, Pascal, and, at least in the Commodore and Compis versions, the turtle graphics of Logo. The language was meant to introduce structured programming elements in an environment where BASIC would normally be used. In early versions, the primary additions to the language were block versions of IF...THEN, and the PROC construct. In most previous versions of BASIC, the only block construct was the FOR...NEXT loop. For instance: This example performs a loop ten times, and performs two instructions every time through the loop. In contrast, almost every other instruction in BASIC, or statement, has to be accomplished on a single line. This can make multi-line statements difficult to perform on an all-or-nothing basis. For instance, if a program desires to run three instructions if a particular value is greater than 10, the typical solution is: This sort of construct hides the true intention of the program, the decision is based on the opposite logic of what the programmer actually wants to accomplish. Additionally, to understand what will happen in this case, the reader has to find line 50, which in real programs might be much further into the source code. This is one of the major reasons that BASIC programs are referred to as "spaghetti code", as to follow the logic one moves around the program as if following a series of random spaghetti noodles. COMAL addresses this issue through the use of blocks. To accomplish this same series of instructions, in COMAL one would write: In this case, the author writes the decision they are actually trying to accomplish, and the reader can follow the logic simply by looking for the ENDIF. This is aided by COMAL's use of leading spaces to visually indicate blocks. Examples Availability COMAL was available for: See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/D%C3%A9j%C3%A0_vu] | [TOKENS: 3185] |
Contents Déjà vu Déjà vu (/deɪʒɑː v(j)uː/ ⓘ DAY-jah-VOO, -VEW, French: [deʒa vy] ⓘ; "already seen") is the phenomenon of feeling like one has lived through the present situation in the past. It is an illusion of memory whereby—despite a strong sense of recollection—the time, place, and context of the "previous" experience are uncertain or impossible. Approximately two-thirds of surveyed populations report experiencing déjà vu at least one time in their lives. The phenomenon manifests occasionally as a symptom of seizure auras, and some researchers have associated chronic or frequent "pathological" déjà vu with neurological or psychiatric illness. Experiencing déjà vu has been correlated with higher socioeconomic status, better educational attainment, and lower ages. People who travel often, frequently watch films, or frequently remember their dreams are also more likely to report experiencing déjà vu than others. History The term was first used by Émile Boirac in 1876. Boirac was a French philosopher whose book L'avenir des sciences psychiques (lit. 'The Future of the Psychic Sciences') included the sensation of déjà vu. Déjà vu has been presented by Émile as a reminiscence of memories, "These experiments have led scientists to suspect that déjà vu is a memory phenomenon. We encounter a situation that is similar to an actual memory but we can’t fully recall that memory." This evidence, found by Émile Boirac, helps the public understand what déjà vu can entail on the average brain. It was also stated by Boirac, "Our brain recognizes the similarities between our current experience and one in the past ... left with a feeling of familiarity that we can't quite place." Throughout history, there have been many theories on what causes déjà vu. Medical disorders Déjà vu is associated with temporal lobe epilepsy. This experience is a neurological anomaly related to epileptic electrical discharge in the brain, creating a strong sensation that an event or experience currently being experienced has already been experienced in the past. Migraines with aura are also associated with déjà vu. Early researchers tried to establish a link between déjà vu and mental disorders such as anxiety, dissociative identity disorder and schizophrenia but failed to find correlations of any diagnostic value. No special association has been found between déjà vu and schizophrenia. A 2008 study found that déjà vu experiences are unlikely to be pathological dissociative experiences.[medical citation needed] Some research has looked into genetics when considering déjà vu. Although there is not currently a gene associated with déjà vu, the LGI1 gene on chromosome 10 is being studied for a possible link. Certain forms of the gene are associated with a mild form of epilepsy, and, though by no means a certainty, déjà vu, along with jamais vu, occurs often enough during seizures (such as simple partial seizures) that researchers have reason to suspect a link. Pharmacology Certain combinations of medical drugs have been reported to increase the chances of déjà vu occurring in the user. Taiminen and Jääskeläinen (2001) explored the case of an otherwise healthy person who started experiencing intense and recurrent sensations of déjà vu upon taking the drugs amantadine and phenylpropanolamine together to relieve flu symptoms. Because of the dopaminergic action of the drugs and previous findings from electrode stimulation of the brain (e.g. Bancaud, Brunet-Bourgin, Chauvel, & Halgren, 1994), Taiminen and Jääskeläinen speculated that déjà vu occurs as a result of hyperdopaminergic action in the medial temporal areas of the brain. A similar case study by Karla, Chancellor, and Zeman (2007) suggests a link between déjà vu and the serotonergic system, after an otherwise healthy woman began experiencing similar symptoms while taking a combination of 5-hydroxytryptophan and carbidopa. Explanations Déjà vu may happen if a person experienced the current sensory experience twice successively. The first input experience is brief, degraded, occluded, or distracted. Immediately following that, the second perception might be familiar because the person naturally related it to the first input. One possibility behind this mechanism is that the first input experience involves shallow processing, which means that only some superficial physical attributes are extracted from the stimulus. Research has associated déjà vu experiences with good memory functions, particularly long-term implicit memory. Recognition memory enables people to realize the event or activity that they are experiencing has happened before. When people experience déjà vu, they may have their recognition memory triggered by certain situations which they have never encountered. The similarity between a déjà-vu–eliciting stimulus and an existing, or non-existing but different, memory trace may lead to the sensation that an event or experience currently being experienced has already been experienced in the past. Thus, encountering something that evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu. In an effort to reproduce the sensation experimentally, Banister and Zangwill (1941) used hypnosis to give participants posthypnotic amnesia for material they had already seen. When this was later re-encountered, the restricted activation caused thereafter by the posthypnotic amnesia resulted in three of the ten participants reporting what the authors termed "paramnesias". Two approaches are used by researchers to study feelings of previous experience, with the process of recollection and familiarity. Recollection-based recognition is the ostensible realization that the current situation has occurred before. Familiarity-based recognition is the feeling of familiarity with the current situation without being able to identify any specific memory or previous event that could be associated with the sensation. In 2010, O'Connor, Moulin, and Conway developed another laboratory analog of déjà vu based on two contrast groups of carefully selected participants, a group under posthypnotic amnesia condition (PHA) and a group under posthypnotic familiarity condition (PHF). The idea of PHA group was based on the work done by Banister and Zangwill (1941), and the PHF group was built on the research results of O'Connor, Moulin, and Conway (2007). They applied the same puzzle game for both groups, "Railroad Rush Hour", a game in which one aims to slide a red car through the exit by rearranging and shifting other blocking trucks and cars on the road. After completing the puzzle, each participant in the PHA group received a posthypnotic amnesia suggestion to forget the game in the hypnosis. Then, each participant in the PHF group was not given the puzzle but received a posthypnotic familiarity suggestion that they would feel familiar with this game during the hypnosis. After the hypnosis, all participants were asked to play the puzzle (the second time for PHA group) and reported the feelings of playing. In the PHA condition, if a participant reported no memory of completing the puzzle game during hypnosis, researchers scored the participant as passing the suggestion. In the PHF condition, if participants reported that the puzzle game felt familiar, researchers scored the participant as passing the suggestion. It turned out that, both in the PHA and PHF conditions, five participants passed the suggestion and one did not, which is 83.33% of the total sample. More participants in PHF group felt a strong sense of familiarity, for instance, comments like "I think I have done this several years ago." Furthermore, more participants in PHF group experienced a strong déjà vu, for example, "I think I have done the exact puzzle before." Three out of six participants in the PHA group felt a sense of déjà vu, and none of them experienced a strong sense of it. These figures are consistent with Banister and Zangwill's findings. Some participants in PHA group related the familiarity when completing the puzzle with an exact event that happened before, which is more likely to be a phenomenon of source amnesia. Other participants started to realize that they may have completed the puzzle game during hypnosis, which is more akin to the phenomenon of breaching. In contrast, participants in the PHF group reported that they felt confused about the strong familiarity of this puzzle, with the feeling of playing it just sliding across their minds. Overall, the experiences of participants in the PHF group is more likely to be the déjà vu in life, while the experiences of participants in the PHA group is unlikely to be real déjà vu. A 2012 study in the journal Consciousness and Cognition, that used virtual reality technology to study reported déjà vu experiences, supported this idea. This virtual reality investigation suggested that similarity between a new scene's spatial layout and the layout of a previously experienced scene in memory (but which fails to be recalled) may contribute to the déjà vu experience. When the previously experienced scene fails to come to mind in response to viewing the new scene, that previously experienced scene in memory can still exert an effect—that effect may be a feeling of familiarity with the new scene that is subjectively experienced as a feeling that an event or experience currently being experienced has already been experienced in the past, or of having been there before despite knowing otherwise. In 2018 a study examined volunteers' brains under experimentally induced déjà vu through the use of fMRI brain scans. The induced "deja vu" state was created by getting them to look at a series of logically related and unrelated words. The researchers would then ask the participants how many words starting with a specific letter they saw. With related words such as "door, shutter, screen, breeze", the participants would be asked if they saw any words that started with "W" (i.e. Window, a term that was not presented to the participants). If they did note that they thought they saw a word that wasn't presented to them, then déjà vu was induced. The researchers would then examine the volunteers' brains at the moment of induced déjà vu. From these scans, they noticed that there was visible activity in regions of the brain associated with mnemonic conflict. This finding suggests that more research regarding memory conflict may be important in better understanding déjà vu. Another possible explanation for the phenomenon of déjà vu is the occurrence of cryptomnesia, which is where information learned is forgotten but nevertheless stored in the brain, and similar occurrences invoke the contained knowledge, leading to a feeling of familiarity because the event or experience being experienced has already been experienced in the past, known as "déjà vu". Some experts suggest that memory is a process of reconstruction, rather than a recollection of fixed, established events. This reconstruction comes from stored components, involving emotions, distortions, and omissions. Each successive recall of an event is merely a recall of the last reconstruction. The proposed sense of recognition (déjà vu) involves achieving a good match between the present experience and the stored data. This reconstruction, however, may now differ so much from the original event it is as though it had never been experienced before, even though it seems similar. In 1965, Robert Efron of Boston's Veterans Hospital proposed that déjà vu is caused by dual neurological processing caused by delayed signals. Efron found that the brain's sorting of incoming signals is done in the temporal lobe of the brain's left hemisphere. However, signals enter the temporal lobe twice before processing, once from each hemisphere of the brain, normally with a slight delay of milliseconds between them. Efron proposed that if the two signals were occasionally not synchronized properly, then they would be processed as two separate experiences, with the second seeming to be a re-living of the first. Dreams can also be used to explain the experience of déjà vu, and they are related in three different aspects. Firstly, some déjà vu experiences duplicate the situation in dreams instead of waking conditions, according to the survey done by Brown (2004). Twenty percent of the respondents reported their déjà vu experiences were from dreams and 40% of the respondents reported from both reality and dreams. Secondly, people may experience déjà vu because some elements in their remembered dreams were shown. Research done by Zuger (1966) supported this idea by investigating the relationship between remembered dreams and déjà vu experiences, and suggested that there is a strong correlation. Thirdly, people may experience déjà vu during a dream state, which links déjà vu with dream frequency. Collective unconscious is a controversial theory created by Carl Jung that has been used to explain the phenomenon of déjà vu. His theory is that all people have a shared pool of knowledge that has been passed down through generations and we can unconsciously access this knowledge. Some of said knowledge would be about certain archetypes like mother, father and hero or possibly about basic situations, emotions or other patterns. If we can access shared knowledge, déjà vu could potentially be an effect of recognizing one of the collectively stored patterns.[citation needed] Related terms Jamais vu (from French, meaning "never seen") is any familiar situation which is not recognized by the observer. Often described as the opposite of déjà vu, jamais vu involves a sense of eeriness and the observer's impression of seeing the situation for the first time, despite rationally knowing that they have been in the situation before. Jamais vu is most commonly experienced when a person momentarily does not recognize a word, person or place that they already know. Jamais vu is sometimes associated with certain types of aphasia, amnesia, and epilepsy. Theoretically, a jamais vu feeling in someone with a delirious disorder or intoxication could result in a delirious explanation of it, such as in the Capgras delusion, in which the patient takes a known person for a false double or impostor. If the impostor is himself, the clinical setting would be the same as the one described as depersonalization, hence jamais vus of oneself or of the "reality of reality", are termed depersonalization (or surreality) feelings. The feeling has been evoked through semantic satiation. Chris Moulin of the University of Leeds asked 95 volunteers to write the word "door" 30 times in 60 seconds. Sixty-eight percent of the subjects reported symptoms of jamais vu, with some beginning to doubt that "door" was a real word. Déjà vécu (from French, meaning "already lived") is an intense, but false, feeling of having already lived through the present situation. Recently, it has been considered a pathological form of déjà vu. However, unlike déjà vu, déjà vécu has behavioral consequences. Patients with déjà vécu often cannot tell that this feeling of familiarity is not real. Because of the intense feeling of familiarity, patients experiencing déjà vécu may withdraw from their current events or activities. Patients may justify their feelings of familiarity with beliefs bordering on delusion. Presque vu (French pronunciation: [pʁɛsk vy], from French, meaning "almost seen") is the intense feeling of being on the very brink of a powerful epiphany, insight, or revelation, without actually achieving the revelation. The feeling is often therefore associated with a frustrating, tantalizing sense of incompleteness or near-completeness. Déjà rêvé (from French, meaning "already dreamed") is the feeling of having already dreamed something that is currently being experienced. Déjà entendu (literally "already heard") is the experience of feeling sure about having already heard something, even though the exact details are uncertain or were perhaps imagined. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Gemara] | [TOKENS: 2114] |
Contents Gemara The Gemara (also transliterated Gemarah, or in Yiddish Gemore) comprises a collection of rabbinical analyses and commentaries on the Mishnah and presented in 63 books. The term is derived from the Aramaic word גמרא and rooted in the Semitic word ג-מ-ר (gamar), which means "to finish" or "complete". Initially, the Gemara was transmitted orally and not permitted to be written down. However, after Judah the Prince compiled the Mishnah around 200 CE, rabbis from Babylonia and the Land of Israel extensively studied the work. Their discussions were eventually documented in a series of books, which would come to be known as the Gemara. There are two versions of the Talmud: the Babylonian Talmud (Talmud Bavli) and the Jerusalem Talmud (Talmud Yerushalmi). The Mishnah is virtually the same in two Talmuds; the Gemara is what differentiates the Babylonian Talmud from its Jerusalem counterpart. The Babylonian Talmud, compiled by scholars in Babylonia around 500 CE and primarily from the academies of Sura, Pumbedita, and Nehardea, is the more commonly cited version when referring to the "Gemara" or "Talmud"; redaction of the Jerusalem Talmud was interrupted in the mid-fourth century when the Romans suppressed Jewish scholarship in the Palestinian provinces and most Talmudists fled to Babylon. As a result, the Bavli was more intensively edited, studied, and commented on. The main compilers of the Babylonian Talmud were Ravina and Rav Ashi. The Jerusalem Talmud was compiled by Jewish scholars in the Land of Israel, primarily from the academies of Tiberias and Caesarea, around 350–400 CE. The Talmud is organized into six sedarim, or "orders," which include Zeraim, Moed, Nashim, Nezikin, Kodshim, and Taharot. In 1923, Polish Rabbi Meir Shapiro introduced a contemporary practice called "Daf Yomi," or "daily page," wherein participants study one page of the Talmud daily in cycles lasting seven and a half years each. This initiative ensures that both scholars and laypeople across the globe engage in the comprehensive study of the entire Talmud. Gemara and Mishnah Maimonides describes the Gemara as: understanding and conceptualizing the ultimate derivation of a concept from its roots, inferring one concept from another and comparing concepts, understanding [the Law] based on the principles of Torah exegesis, until one appreciates the essence of those principles and how the prohibitions and the other decisions which one received according to the oral tradition (i.e. Mishnah) can be derived using them.... The rabbis of the Mishnah are known as Tannaim (sing. Tanna תנא). The rabbis of the Gemara are referred to as Amoraim (sing. Amora אמורא). The analysis of the Amoraim, recorded as gemara, is thus focused on clarifying the positions, views, and word choice of the Tannaim. Because there are two Gemaras, as mentioned above, there are in fact two Talmuds: the Jerusalem Talmud (Hebrew: תלמוד ירושלמי, "Talmud Yerushalmi"), and the Babylonian Talmud (Hebrew: תלמוד בבלי, "Talmud Bavli"), corresponding to the Jerusalem Gemara and the Babylonian Gemara; both share the same Mishnah. The Gemara is mostly written in Aramaic, the Jerusalem Gemara in Western Aramaic and the Babylonian in Eastern Aramaic, but both contain portions in Hebrew. Sometimes the language changes in the middle of a story. Origins of the word In a narrow sense, the word gemara refers to the mastery and transmission of existing tradition, as opposed to sevara, which means the deriving of new results by logic. Both activities are represented in the Gemara as one literary work. The Aramaic noun gemar (and gemara) was formed from the verb that means "learn." This substantive noun thus designates what was learned, and the learning transmitted to scholars by tradition, though it connotes in a more limited sense to exposition of the Mishnah. The word therefore gained currency as a designation of the Talmud. In the modern editions, the term gemara occurs frequently in this sense—but in nearly every case it was substituted at a later time for the objectionable word talmud, which was prohibited by the Christian censors. The only passage in which gemara occurs with the meaning of "Talmud" in the strict sense, and not censored, is Eruvin 32b, where it is used by Rav Nahman, a Babylonian amora (3rd C.). Later editions of the Talmud frequently substitute for the word "Gemara" the Aramaic abbreviation for "the six orders of the Mishnah," pronounced as "Shas," which has become a popular designation for the Babylonian Talmud. The Sugya The building block of gemara is known as a sugya, "a self-contained basic unit of Talmudic discussion" (p. 203) that often centers on a statement from the mishnah, the amoraic rabbis (memra), or simply independent of these. They vary in size and complexity and, though self-contained, may mention or assume knowledge of other sugiyot. The analysis of the Amoraim is generally focused on clarifying the positions, words and views of the Tannaim. These debates and exchanges form the "building-blocks" of the Gemara; the name for such a passage of Gemara is a sugya (סוגיא; plural sugyot). A sugya will typically comprise a detailed proof-based elaboration of the Mishna. Every aspect of the Mishnaic text is treated as a subject of close investigation. This analysis is aimed at an exhaustive understanding of the Mishna's full meaning. In the Talmud, a sugya is presented as a series of responsive hypotheses and questions – with the Talmudic text as a record of each step in the process of reasoning and derivation. The Gemara thus takes the form of a dialectical exchange (by contrast, the Mishnah states concluded legal opinions – and often differences in opinion between the Tannaim. There is little dialogue). The disputants here are termed the makshan (questioner, "one who raises a difficulty") and tartzan (answerer, "one who puts straight"). The Gemara records the semantic disagreements between Tannaim and Amoraim. Some of these debates were actually conducted by the Amoraim, though many of them are hypothetically reconstructed by the Talmud's redactors. (Often imputing a view to an earlier authority as to how he may have answered a question: "This is what Rabbi X could have argued ...") Only rarely are debates formally closed. Argumentation and debate The distinctive character of the gemara derives largely from the intricate use of argumentation and debate, described above; these "back and forth" analytics are characterized by the Talmudic phrase shakla v'tarya (שקלא וטריא; lit. "taking and throwing"). In each sugya, either participant may cite scriptural, Mishnaic and Amoraic proof to build a logical support for their respective opinions. The process of deduction required to derive a conclusion from a prooftext is often logically complex and indirect. "Confronted with a statement on any subject, the Talmudic student will proceed to raise a series of questions before he satisfies himself of having understood its full meaning." This analysis has been described as "mathematical" in approach; Adin Steinsaltz makes the analogy of the Amoraim as scientists investigating the Halakha, where the Tanakh, Mishnah, Tosefta and midrash are the phenomena studied. Prooftexts quoted to corroborate or disprove the respective opinions and theories will include: The actual debate will usually centre on the following categories: Why does the Mishna use one word rather than another? If a statement is not clear enough, the Gemara seeks to clarify the Mishna's intention. Exploring the logical principles underlying the Mishnah's statements, and showing how different understandings of the Mishnah's reasons could lead to differences in their practical application. What underlying principle is entailed in a statement of fact or in a specific instance brought as an illustration? If a statement appears obvious, the Gemara seeks the logical reason for its necessity. It seeks to answer under which circumstances a statement is true, and what qualifications are permissible. All statements are examined for internal consistency. See: List of Talmudic principles and Category:Talmud concepts and terminology Resolving contradictions, perceived or actual, between different statements in the Mishnah, or between the Mishnah and other traditions; e.g., by stating that: two conflicting sources are dealing with differing circumstances; or that they represent the views of different rabbis. Do certain authorities differ or not? If they do, why do they differ? If a principle is presented as a generalization, the Gemara clarifies how much is included; if an exception, how much is excluded. Demonstrating how the Mishnah's rulings or disputes derive from interpretations of Biblical texts, the Gemara will often ask where in the Torah the Mishnah derives a particular law. See Talmudic hermeneutics and Oral Torah § The interplay of the Oral and Written Law. See also Further reading References This article incorporates text from a publication now in the public domain: Singer, Isidore; et al., eds. (1901–1906). "Talmud". The Jewish Encyclopedia. New York: Funk & Wagnalls. External links |
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[SOURCE: https://en.wikipedia.org/wiki/Genshi_(templating_language)] | [TOKENS: 234] |
Contents Genshi (templating language) Genshi is a template engine for XML-based vocabularies written in Python. Genshi is used to easily insert generated output into XML-based languages, usually HTML, and reuse elements between documents. Genshi's syntax is based on Kid, but its architecture is different. Genshi aims to implement some of its functionality while processing templates faster, by dynamically processing templates using a stream based API, instead of compiling templates to Python code. Genshi can be used with several Python web frameworks, such as CherryPy, TurboGears, Pylons and web2py. Genshi was the default templating language for TurboGears from versions 1.1 to 2.3.8. Genshi markup Genshi makes use of namespaces to embed instructions into HTML. A typical instruction is given as an attribute, with a Python expression inside the quotes. For example, the following will render a paragraph that shows 4: Because of the use of namespaces, Genshi can be used in WYSIWYG HTML editors. Differences between Kid and Genshi References External links |
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[SOURCE: https://en.wikipedia.org/wiki/COMIT] | [TOKENS: 176] |
Contents COMIT COMIT was the first string processing language (compare SNOBOL, TRAC, and Perl), developed on the IBM 700/7000 series computers by Victor Yngve, University of Chicago, and collaborators at MIT from 1957 to 1965. Yngve created the language for supporting computerized research in the field of linguistics, and more specifically, the area of machine translation for natural language processing. The creation of COMIT led to the creation of SNOBOL, which stand out apart from other programming languages of the era (during the 50s and 60s) for having patterns as first class data type. Bob Fabry, University of Chicago, was responsible for COMIT II on Compatible Time-Sharing System. References This programming-language-related article is a stub. You can help Wikipedia by adding missing information. |
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[SOURCE: https://en.wikipedia.org/wiki/Response_to_the_Department_of_Government_Efficiency] | [TOKENS: 8912] |
Contents Response to the Department of Government Efficiency The actions of the Department of Government Efficiency (DOGE) have attracted reactions from officials, scholars, and citizens. While a majority supports the creation of an agency dedicated to efficiency efforts, most opinion polls show opposition to DOGE and Elon Musk. Representatives created task forces to support DOGE efforts to cut waste. Countrywide protests have been organized to oppose mass layoffs, service cuts, privatization, and data extraction; United States Digital Service employees have resigned in protest. Various groups have sued DOGE, Musk, and the Trump administration. Supporters have emphasized the need for efficiency and fiscal responsibility; they have expressed hope that DOGE will cut down on wasteful spending. Unitary executive theory advocates argue that the bureaucracy forms a "fourth branch of government" that should be bent to the President's will. Critics have spoken of a corporate coup of the US government by an entity they deem unaccountable and unconstitutional. Security experts have pointed to national security and cybersecurity risks created by DOGE teams rushing into critical infrastructure. Potential conflicts of interest have been raised about Musk and his associates: with government contracts that clash with federal regulators, which DOGE is trying to slash. The administration suggested that Musk would recuse himself if his interests conflicted. DOGE has been accused of pursuing a symbolic culture war rather than targeting wasteful spendings. Multi-billion-dollar mistakes have been reported in savings DOGE claimed. Public opinion On January 24, 2025, the AP-NORC Center for Public Affairs Research published poll results showing that 39% of Americans disapprove and 29% approve of DOGE, while 52% hold an unfavorable opinion of Musk. On February 23, Axios reported that multiple polls showed that a majority of Americans disapprove of DOGE's dissection of the government and of the amount of power Musk has gained. A February 24 poll of 2,443 American voters from Harvard Caps/Harris found that 72% of respondents supported the existence of an organization focused on cutting government waste; 60% of respondents answered that they believed DOGE was helping to make major cuts to federal spending; 58% said DOGE employees should not have access to sensitive information on Americans who benefit from government expenditure programs, including names, social security numbers, addresses, and incomes. A February 2025 poll of 1,000 American voters from Napolitan News Service found that 47% of respondents supported DOGE's cuts, 39% were opposed, and 13% were unsure. A survey at the end of February by Axios and Generation Lab found that 71% of voters under the age of 35 disapproved of DOGE's actions. On March 2, CBS/YouGov released the results of a survey showing that 27% of Americans (17% of Democrats, 25% of Independents, and 39% of Republicans) believe that DOGE should have a lot of influence over government operations and spending; the majority (52%) believes that DOGE and Musk have too much access to government data records. On April 20, a University of Massachusetts Amherst poll showed a majority did not trust Musk to identify federal programs to cut (53%), protect citizen privacy (55%), or avoid conflict of interests (59%); a majority of Americans (56%) believe that Musk has too much influence over the federal government. In April, a Washington Post and Ipsos poll showed that over two thirds of Americans are concerned about DOGE data access. Mobilization On November 19, 2024, Rep. Aaron Bean (R-FL) and Rep. Pete Sessions (R-TX) launched the congressional Delivering Outstanding Government Efficiency Caucus (DOGE Caucus) to reduce waste, fraud, and abuse in the federal government. House Oversight Committee chairman James Comer (R-KY) announced plans two days later for a new subcommittee called the Delivering on Government Efficiency Subcommittee, which would be chaired by Rep. Marjorie Taylor Greene (R-GA). On November 22, Senator Joni Ernst (R-IA) was appointed to lead the corresponding Senate DOGE Caucus. Several Democrats have expressed willingness to work with the Congressional Caucus, including Rep. Jared Moskowitz (D-FL), Rep. Tom Suozzi (D-NY), and Rep. Val Hoyle (D-OR). Others offered ideas: Rep. Ro Khanna (D-CA) on agency redundancies, online tax forms, fossil fuel subsidies, and IT systems; Rep. Greg Landsman (D-OH) on government form size; Rep. Ritchie Torres (D-NY) on permit processes; and Rep. Jared Golden (D-ME) on sending federal agencies back to states. On December 17, the Congressional Caucus held its first meeting, with over 60 attendees, including Democrats Steven Horsford (D-NV), Hoyle, and Moskowitz. Lawmakers described it as largely organizational, with discussions about "low-hanging fruit", such as cutting remote work. The next day, Ernst proposed a "Drain the Swamp Act" bill, requiring agencies to relocate 30 percent of Washington, D.C., employees outside the metro area while restricting the ability to telework. Moskowitz proposed days later to make the Federal Emergency Management Agency and the Secret Service independent from the Department of Homeland Security. On February 5, Hoyle left the caucus, citing disillusionment with DOGE's goals: "it is apparent that [Musk] sees DOGE's work is to find funds to give tax breaks for billionaires at the expense of working people, not about doing right by them." The same day, Moskowitz voiced uncertainty on staying in the caucus, seeing no purpose; a week later he criticized the lack of collaboration between DOGE and the caucus: "Elon's been doing it all himself." In May, Moskowitz declared the DOGE Caucus 'dead', saying, "We haven't met in months. We only had two total meetings in five months. And we weren't involved at all in anything [happening at DOGE], which Elon was in charge of." Moskowitz said he was told by the caucus co-chairs that DOGE would work with the caucus, but "None of it happened." Co-chair Aaron Bean said that the caucus was "just getting started". In February 2025, Governor Ron DeSantis of Florida established the Florida Department of Government Efficiency, the first state-level equivalent of DOGE. In April 2025, Governor Kevin Stitt of Oklahoma followed suit and issued an executive order to create an Oklahoma Division of Government Efficiency (DOGE-OK). In April, Governor Greg Abbott of Texas launched an agency modeled after DOGE. As of May 2025[update], there are more than 20 state-level DOGE organizations. In June 2025, Reform UK announced the start of a DOGE-inspired initiative to identify and slash wasteful spending by councils. The concept of a DOGE for the European Union has received support from European CEOs Tim Höttges and Patrick Pouyanné, as well as European Parliament member Axel Voss. As of April 21, 2025[update], protests against DOGE are ongoing. Protestors appeared at Tesla showrooms in numerous cities in the US in February. One of the larger protests took place outside Tesla's Manhattan showroom, where protestors could be heard chanting "Elon Musk can go to Mars; we don't need your Nazi cars" referring to the Elon Musk salute controversy and Musk's support for Alternative for Germany. Protests also took place in San Francisco, Berkeley, Minneapolis, and Kansas City among others. Musician Sheryl Crow posted a video on social media showing a flatbed truck removing a Tesla she had sold in protest. Protests happened outside Tesla stores nationwide in response to significant federal layoffs led by Elon Musk. Demonstrations have occurred in cities such as New York, Jacksonville, and Tucson, with participants criticizing Musk's role in implementing substantial cuts to the federal workforce. In New York City, nine individuals were arrested during a protest at a Tesla store, reflecting the intensity of public sentiment. The "Tesla Takedown" movement has gained momentum, with activists urging the public to divest from Tesla and participate in picket lines to challenge the administration. In early February, employees at the Technology Transformation Services, a technology office within the General Services Administration, protested against Trump appointee Thomas Shedd during an internal meeting where he was encouraging staff to consider the deferred resignation program. Employees flooded the video conferencing chat with spoon emojis in opposition to Shedd, Musk and DOGE. Spoons were chosen in light of the initial email about the deferred resignation program, titled "Fork in the Road". On February 3, protesters gathered outside the Office of Personnel Management and indicated that they would continue to protest for the rest of the week in opposition to DOGE and Musk. The protestors claimed that Musk had illegally taken control of the government's infrastructure, and raised concerns that Musk was an unelected foreign national who was potentially stealing sensitive information stored in federal servers. A rally was organized in front of the Treasury Department the next day via word of mouth and social media, with initially 50 participants that grew into hundreds. Participants included federal workers, retirees and others who were alarmed and angry over Musk and DOGE's actions and its trajectory, chanting "Elon Musk has to go" and signs reading "No Trump, No Musk, No Fascist USA" and "Musk owns Trump". Democratic politicians such as Senator Chuck Schumer, Senator Chris Van Hollen, and Representative Maxine Waters spoke out at the protest. About every day in April, millions of people across the United States organized as part of the "Hands Off!" protest. Protestor frustrations included Musk's involvement in government downsizing. The April protests converge toward a national day of action on May, 1. House Republican Rich McCormick was booed at a town hall in Georgia as he defended the administration's actions. Many constituents turned out to town hall meetings held by members of Congress in February, 2025, and voiced their concerns and anger about the mass layoffs. The Republican leadership in the House of Representatives suggested that members stop holding town halls or use video town halls, as a means of preventing viral video clips of constituents confronting their representatives. Several National Park Service employees at Yosemite National Park rappelled down the face of El Capitan, a 3,000-foot granite monolith in the park, and hung a 30-foot-by-50-foot upside-down US flag as a distress signal. The group stated "The purpose of this exercise of free speech is to disrupt without violence and draw attention to the fact that public lands in the United States are under attack. ... Firing thousands of staff regardless of position or performance across the nation is the first step in destabilizing the protections in place for these great places." On 1 March 2025 opponents of job cuts rallied in over 100 national parks across the US. A number of protests and national days of action, such as the March 7, 2025 Stand For Science rallies, have opposed funding and staff cuts. On January 21, DOGE representatives conducted interviews with USDS employees about their work and asked which colleagues could be fired. On February 25, 21 USDS employees resigned en masse. They were among the 65 US Digital Service employees who continued to work with the service when US Digital Service became the US DOGE Service. In a letter, they stated that could not honor their oath under DOGE, warned about the politicization of the department, and declared: "We will not use our skills as technologists to compromise core government systems, jeopardize Americans' sensitive data, or dismantle critical public services". One of the 21 USDS technologists who resigned in protest on February 25 stated that DOGE's actions created "a high risk of the American people's data being exposed or being utilized for nefarious means", including the potential for foreign actors to access that data, and she viewed these actions are "completely across the line both legally and ethically". The USDS is part of the DOGE structure by executive order. On April 15, Politico reported that nearly everyone from the Defense Digital Service resigned, after being sidelined by DOGE. On November 1, 2024, Musk mentioned that Ron Paul could work with DOGE; Paul vowed to join; they agreed on cutting military spending; this led nowhere. On February 25, 2025, Politico reported: "Early interest in running for office is already beginning to rise — at least one major candidate recruitment organization saw a sharp spike of more than 2,000 new applications pouring in as Musk issued major actions pushing federal workers out." On March 31, Sen. Ron Wyden, Ed Markey, Jeff Merkley, and Chris Van Hollen introduced the Privacy Act Modernization Act of 2025, which increases civil and criminal penalties for violations of the Privacy Act, strengthens court authority to prevent DOGE-like takeovers, modernizes the conceptual apparatus of the law by narrowing "routine use" exceptions, and limits information sharing. On April 3, Rep. Sara Jacobs introduced the Delete DOGE Act. In an interview on MSNBC she said: "This wholesale firing, this wholesale sort of gutting of these programs—that is not about government efficiency. That is about supposedly finding cuts so that they can fund the tax cuts for billionaires that they really want to pass." In Virginia, Governor Glenn Youngkin created a program, Virginia Has Jobs, to help those impacted by federal layoffs find new employment. Youngkin has defended President Trump's firing of workers. Chuck Borges, who became a whisleblower while being the SSA chief data officer, is running for office. On March 17, two representatives from the House Judiciary and House Oversight committees filed a FOIA request questioning whether DOGE is operating outside the bounds of federal law and stated "the Administration and Mr. Musk have hidden behind a veil of secrecy as they systematically dismantle the federal government of the United States". On January 10, 2025, Republican state governors wrote a joint letter to leaders of Congress expressing "overwhelming support" for DOGE and that they "stand ready to help DOGE—and Congress—be successful". Sen. Elizabeth Warren (D-MA) has sent a letter to Musk with 30 ways to save $2 trillion in the federal budget: stopping waste at the Department of Defense, curbing Medicare insurers abuse, lowering prescription drug costs, cutting into the Federal Charter School Program, closing tax loopholes for the rich, etc. Her recommendations have been ignored. On February 25, the Union of Concerned Scientists delivered a letter signed by more than 2,500 scientists urging Congress and the Trump administration to protect NOAA. Nearly 50 lawmakers sent a letter to Russell Vought on April 16, raising concerns about privacy and security risks created by DOGE's use of federal data in unapproved AI systems; they also express concern about potential conflicts of interest involving Elon Musk, who owns an xAI. Sen. Gary Peters released a report on September 25, 2025, that accused DOGE to operate "outside of, and even counter to, federal law and their purported efficiency and transparency goals" resulting "in serious cybersecurity vulnerabilities, privacy violations, and risk of corruption". Within one week of DOGE's mass layoff plan, the subreddit r/FedNews became a central hub for information sharing by federal government employees of DOGE actions and DOGE actors, and organizing resistance against the Trump administration. The subreddit gained 250,000 members between the 2024 United States presidential election and February 7, 2025, and entered the top 1% of subreddits by subscriber count. The subreddit states that it is unaffiliated with and not endorsed by the United States government. The subreddit describes itself as "a secure space for United States Federal Government employees to express their opinions, share experiences, and discuss news and information pertinent to their employment." Right-wing social media influencers have been critical of it, with unproven allegations of federal employees using Reddit while on duty. On March 1, all the employees of 18F received notice that their positions had been eliminated. In response, the employees launched a website to explain how ill-advised was this DOGE decision. The Union of Concerned Scientists has organized an online petition to pressure the House Oversight Committee in order to "end the secrecy of Elon Musk's campaign against federal workers". On April 6, Musk left a livestream after repeatedly dying to the Path of Exile's first boss and receiving taunts from gamers, to which he responded: "there's a lot of retards in the chat". After Musk demanded that federal employees email at hr@opm.gov, the Internet flooded its inbox. On February 14, 2025, three men wearing shirts that referenced DOGE attempted to gather information they claimed would be related to alleged wasteful spending and fraud from offices in San Francisco City Hall. The men brought flash drives to copy the records and entered public and private spaces through unlocked doors in the building. A building manager later announced that, "They did not present a judicial warrant, and therefore, had no authority to access computers or non public spaces." Employees refused to hand over any information and called the San Francisco Sheriff's Office, but by the time authorities arrived, the unidentified agents had fled the building. DOGE has not confirmed that the agents were with them, and the San Francisco Sheriff's Office believes that they were not. On February 24, 2025, public televisions and monitors in United States Department of Housing and Urban Development offices displayed an artificial intelligence-generated video of President Donald Trump performing fetishistic foot worship upon Elon Musk, with the text "Long live the real king", in reference to Trump describing himself as a king days prior. Commentaries In November 2024, Politico reported on growing concern from the tech world and several policy experts that the project was over-promising or could potentially tear down "much of the essential infrastructure that ushers along American innovation". Former US deputy chief technology officer Jennifer Pahlka stated that while civil service reform was needed, mass firings were the wrong answer. Senior fellow Jessica Riedl at the Manhattan Institute said that DOGE's plan to fire 25% of the federal workforce would reduce only 1% of federal funding and require the hiring of contractors to fulfill the difference. The Washington Post cited critics who stated balancing the budget would require higher taxes or cuts to Medicare or Social Security, and DOGE's proposal to slash federal programs that Congress funds but whose authority had lapsed would cut "veterans' health care, initiatives at the State and Justice departments and NASA, and multiple major antipoverty programs". The Post also cited budget experts who said Musk and Ramaswamy's plan "demonstrates the pair's misunderstanding of how the government works". Laurence Tribe, constitutional scholar at Harvard Law School, argues that the power that Musk and DOGE attempt to exercise over federal departments is illegal. He asserts that Musk "absolutely" faces a conflict of interest in his roles as a government contractor and federal employee. Musk's software system takeovers raise "serious issues of privacy" according to Tribe. Some business leaders supported the idea of the effort in the months before Trump took office. Many Republicans are supportive of DOGE's efforts to cut the budget. Some Republicans are concerned about DOGE, because its actions negatively impact their home states or are performed without transparency. Trump's Commerce Secretary Howard Lutnick described DOGE's cuts as "backward", saying they focused too much on cutting the workforce rather than reducing waste. Andrew Natsios, the administrator for USAID during the George W. Bush administration, told PBS that, "With all due respect, none of these people know anything about AID. What does Musk know about international development? Absolutely nothing. He has a bunch of young kids in their 20s. They don't know. They're techies. They don't know anything about international development. They don't know anything about the Global South. They don't know anything about these—the programs and policies of the agency. AID is the most pro-business and pro-market of all aid agencies in the world. I can tell you that categorically. I am a conservative Republican. I'm not a liberal. And I have served in repeated Republican administrations." In September 2024, Jamie Dimon, the CEO of the bank JPMorgan Chase, stated that he supported the idea of creating DOGE to improve government competency. DOGE has been seen as potentially redundant to the Government Accountability Office. DOGE claimed in its "Wall of Receipts" on its website to have cancelled government contracts totaling about $16 billion. Roughly half of that was attributed to a single $8 billion contract with US Immigration & Customs Enforcement. The New York Times discovered the contract in question was actually only $8 million, making the total dollar amount of cancelled contracts dramatically less than claimed. DOGE claimed the $8 million figure was used in overall savings calculations all along, but the contracting company stated $3.8 million had already been spent, resulting in actual savings of $4.2 million. Meanwhile, the Daily Beast noted that other auditing irregularities are resurfacing, including taking credit for contracts already cancelled under the Biden administration. The Times reporting also noted that cancelled contracts are counted towards the Wall's total using the total value of each contract, even if a majority had already been paid by the government and the funds would not be recuperated. One of the biggest DOGE savings' claims was based on an error. A February 19 X tweet posted by the United States Treasury account, then reposted by DOGE, said that they had saved US$1.9 billion by cancelling a contract, and included a screen shot of the contracting agency code, associated with Centennial Technologies. The company told the Times that the contract was undertaken and completed in 2024 under the Biden administration and before DOGE was in place. By February 22, the savings claim had deflated to $7 billion. The Wall Street Journal published an analysis of that claim and found that the savings "could be closer to $2.6 billion over the next year if spending levels remained constant—and about 2% of the funds would have gone to contracts related to DEI." It noticed the disappearance of two contracts from the site due to triple accounting, and observed that a quarter of the contracts published so far were already paid. The US Agency for International Development cuts were mistakenly counted three times, with DOGE reporting it as cuts amounting to US$655 million. This has now been decreased to US$18 million. The DOGE site had originally posted that the total savings amounted to US$16 billion. By March 3, this numbered had declined to less than US$9 billion. A former employee at DOGE reported he found relatively little examples of federal waste, fraud, or abuse. Axios calls the events "Musk's takeover of Washington" and compares them to the events at Twitter, observing concerns about "brain drain" in both cases if highly knowledgeable workers leave. The events were also called a "takeover" by The Economic Times. The Associated Press reported that Musk had "created an alternative power structure" in the government. During the House Ways and Means Oversight Subcommittee hearing on Internal Revenue Service modernization, Nina Olson, the director of the Center for Taxpayer Rights, described the deferred resignation offers as "coerced job cuts and firings" causing "a brain drain" at the IRS. Tom Nichols assessed that "Musk's assault on expertise is coming from the same wellspring that has been driving much of the public's irrational hostility toward experts for years." On Saturday February 22, US Government employees received an email from the Office of Personnel Management asking them to provide a list of accomplishments from the previous week. Musk wrote on X that failure to reply would be taken as a resignation. The deadline for this response was set to 11:59pm ET on Monday February 24. The American Federation of Government Employees called the email and threat "cruel and disrespectful". Senator Lisa Murkowski (R-Alaska) responded: "Our public workforce deserves to be treated with dignity and respect for the unheralded jobs they perform. The absurd weekend email to justify their existence wasn't it." Senator Tina Smith (D-Minnesota) qualified the stunt: "This is the ultimate dick boss move from Musk - except he isn't even the boss, he's just a dick". Commenting on workers who are at the cusp of retirement, retirement planner and CEO of Dugan Brown, Wayne Brown said: "You're talking about someone who's put in 25 or 30 years of their life toward a pension and health care and life insurance and benefits for life. This decision is causing a lot of real anxiety and real stress and real pressure among these people who, like these positions or not, dedicated their lives to serving their country in some capacity." Conservative actor Zachary Levi, appearing on Fox News, was supportive of DOGE, but directly implored Musk to not terminate or fire federal workers who voted for Donald Trump, saying: "But there are good people, people that voted for Donald Trump who are losing their job. And we got to make sure that we don't leave those folks behind." Columbia University professor Stijn Van Nieuwerburgh argues that the DOGE's fire sale of more than 500 government buildings could crash financial securities linked to commercial mortgages. The Christian Science Monitor reported that, after the USAID freeze, contract lawyers are involved representing farmers selling surplus crops who are worried about future purchases, and business owners who received Department of Agriculture (USDA) grants to invest in renewable energy technology and climate-resistant crops are unsure if they will be paid. Brent Swart, president of the Iowa Soybean Association, says that suspending the USDA puts farmers at risk and jeopardizes programs that demonstrated public returns. Newsweek counted many TikTok accounts posting clips to express their anger or to discuss the link between the USDA freeze and Project 2025. In March 2025, Tesla investor Christopher Tsai said that he hoped that Musk's involvement in DOGE would be temporary, arguing that his political activities have had negative repercussions on the stock market. Investor Mark Cuban said on Bluesky that if "tariffs stay in place for multiple years, and are enforced and inflationary, and DOGE continues to cut and fire, we will be in a far worse situation than 2008", referring to the Great Recession. In November 2024, Brian Armstrong, the CEO of cryptocurrency vendor Coinbase, spoke in support of the idea of DOGE, and has advocated for abolishing the income tax. In March 2025, the IRS stated that staff cuts and disruptions caused by DOGE may lead to a tax revenue drop of 10% or $500 billion for the federal government. In November 2024, Maya MacGuineas of the public policy organization Committee for a Responsible Federal Budget has said that $2 trillion in savings is "absolutely doable" over a period of 10 years, but it would be difficult to do in a single year "without compromising some of the fundamental objectives of the government that are widely agreed upon". Desmond Lachman of the American Enterprise Institute stated that "realistically, there isn't much political willingness to do the tough stuff that [needs] to be done to get the budget under control." Senior director for federal budget policy Bobby Kogan at the Center for American Progress said that $2 trillion in cuts would likely result in 33% cuts to Social Security, Medicare, and every program relating to veterans compensation and healthcare. In December 2024, Douglas Holtz-Eakin of the American Action Forum compared DOGE to the former Grace Commission, which had none of its 150 proposals enacted. Chief economist Mark Zandi of Moody's said that 30% of the federal budget that is non-discretionary is at the lowest level in modern history as a percentage of GDP, and that even finding $200 billion of savings was highly unlikely. Bobby Kogan said that the "threat level for DOGE's recommendations making it through Congress is relatively low... My threat level for them doing some things illegally, unilaterally, is incredibly high." In early February 2025, Business Insider estimated that at its actual pace DOGE would cancel around $67 billion in contracts each year. This corresponds to 3% of Musk's original $2 trillion goal. After having reviewed official data, The Economist discovered that Treasury outflows actually increased since DOGE took over. NPR investigated Musk's claim that DOGE is saving taxpayers billions, but could not trace back the contracts allegedly terminated. On the All-In podcast, Larry Summers agreed that there was a need for reform, but predicted that DOGE will end in failure, telling host Chamath Palihapitiya: "We are firing, en masse, people whose job it is to audit people like you. And the result of that is that we are losing revenue directly". Studies showed that every dollar invested in auditing gets 100% in return and above, and tax specialists fired by DOGE said to have returned magnitude more revenues than their salaries; as John Koskinen, who led the IRS from 2013 to 2017 said: "when you hamstring the IRS, it's just a tax cut for tax cheats." Sharon Parrott, president of the Center on Budget and Policy Priorities, said that DOGE could decimate social programs by stigmatizing them as wasteful. Speaking at a Morgan Stanley conference in March, Musk has said that "we should privatize everything we possibly can." Grover Norquist, who famously said not wanting to abolish government but to "reduce it to the size where I can drag it into the bathroom and drown it in the bathtub", cheered DOGE's cuts. This privatization effort can be seen in the selloff of hundreds of office buildings, many of them historic. Lindsay Owens, the executive director of Groundwork Action, argues that DOGE is more a land grab than an efficiency initiative, and compares it to the Teapot Dome scandal. Columnist Rod Miller echoes that point by imagining a future where public land is no more. Steve Bannon, a long-time Trump and Republican Party influencer, was extremely critical of Musk's DOGE program, saying "Musk is a parasitic illegal immigrant. He wants to impose his freak experiment and play-act as God without any respect for the country's history, tradition or values." Center for Taxpayer Rights executive director Nina Olsen questions DOGE's capacity to recognize fraud: a background in tax law is required; determination falls on the relevant authority; proving fraud requires an audit. The leadership and membership of DOGE is unclear, as is the role of Elon Musk in government. Judges, journalists, and DOGE itself have drawn no clear distinction between Musk's employees, political appointees associated with Musk, and DOGE personnel. On February 17, Judge Tanya Chutkan asked that Elon Musk's legal status regarding DOGE's actions be clarified. In response, the government stated that Musk "has no actual or formal authority to make government decisions himself" and that "he is an employee of the White House Office." Journalist Marcy Wheeler views this defense as a way to create retroactive continuity for DOGE. Wheeler also cites Ryan Goodman's evidence of times when Donald Trump and Elon Musk themselves contradicted the government position. Kedric Payne, general counsel at the Campaign Legal Center, questions the ethics of Musk's role: "I don't see a legal way for Musk to lead DOGE in the way that it's been described and stay in compliance with the ethics rules". The role of Steve Davis, a longtime associate of Musk, is also unclear. According to Wired, a former staffer at USDS asked managers if Davis was administrator or interim administrator, and was told that the status of Davis within USDS or DOGE was unknown. Journalists have also noted that DOGE itself is amorphous. The Atlantic called it "a disembodied specter," observing that "much of the cost savings that Musk has touted as DOGE victories on social media have been carried out by other appointees." The New York Times notes that judges in numerous court cases have been unable to establish basic facts about the staff members who have targeted federal agencies: "Attempts to press for specifics, such as how many associates of Mr. Musk have been detailed to specific agencies, whether they have arrived as employees of those agencies or as representatives from the White House, and what grounds they have for demanding entry into agencies' systems, have been largely unsuccessful." There is also ambiguity about what actions can be attributed to DOGE. The DOGE X account claimed credit for a $1.9 billion IRS contract rescinded "in connection" with DOGE. The contract was actually cancelled during the Biden administration. Democratic representative Zoe Lofgren (CA-18) has criticized DOGE, calling it "unconstitutional and illegal" in relation to its proposals regarding the impoundment of appropriated funds by Congress. Democratic representative Ro Khanna (CA-17) stated that he was "appalled by the unconstitutional efforts to block funding appropriated and authorized by Congress" and that he relayed those concerns to Musk. Independent Senator Bernie Sanders initially supported plans by Musk to cut defense spending. He soon opposed DOGE, calling its actions illegal and unconstitutional, and repeatedly criticized Musk. Elizabeth Popp Berman, Richard H. Price Professor of Organizational Studies at the University of Michigan contends that DOGE could be using the payments system to overrule spending already approved by Congress and use this power for ideological control. The Impoundment Control Act of 1974 makes this illegal. How DOGE politicizes an apolitical process increases risks of corruption. James Sample, constitutional law scholar at Hofstra University, questions the legality of DOGE's power centralization: "Musk manifestly answers only to Trump. Answering only to the President while wielding vast and enormous power is basically the Platonic form of a principal officer, thus requiring Senate confirmation". Danielle Citron, Jefferson Scholars Foundation Distinguished Professor in Law and LawTech Center Co-Director at University of Virginia School of Law, traces the Privacy Act of 1974 back to the commitment to "transparency, accountability, and protections around the collection, use, and sharing of personal data." The Privacy Law prevents any access to the systems of records of an agency without proper vetting and authorization. Citron concludes: "We are bearing witness to the kind of power grab, abuse, and overreach that the Privacy Act of 1974 was passed to prevent". Under Trump's second administration, the Privacy Act has been cited in up to fourteen lawsuits pertaining to DOGE access to data that could contain sensitive personal data. Congressional leader Gerry Connolly stated "I am concerned that DOGE is moving personal information across agencies without the notification required under the Privacy Act or related laws, such that the American people are wholly unaware their data is being manipulated in this way." Due to the recent lawsuits, Congressional leader Lori Trahan announced an effort to modernize and update the Act to address growing concerns about government surveillance, unvetted access, and misuse. Jessica Riedl, a Republican and Manhattan Institute senior fellow on budget, tax, and economic policy, found that DOGE sought to satisfy Trump's culturally conservative base rather than targeting the biggest government spending sources. Riedl said: "So far, DOGE seems more about looking for symbolic culture war savings than truly reducing the budget deficit in any meaningful way". Alex Nowrasteh, Cato Institute vice president for social and economic policies, echoed the sentiment, describing the cost cuts as "to the federal government, it's nothing". Multiple news agencies have raised questions as to whether Musk's companies being contractors to the federal government causes a conflict of interest with their proposed work in DOGE. Representative Greg Landsman described DOGE as "a way for the wealthiest person alive, who gets billions in federal money, to hack the federal government data and payment system at the expense of the American people". The National Reconnaissance Office signed a contract in 2021 for $1.8 billion with Musk's SpaceX. Journalist Malika Khurana lists 11 agencies impacted by DOGE with federal investigations or regulatory battles with Elon Musk's businesses. Investigative journalist Eric Lipton uncovered 32 investigations, complaints or enforcement actions into Musk's companies. On February 18, Reuters reported that Food and Drug Administration employees reviewing Musk's company Neuralink were fired by DOGE. White House press secretary Karoline Leavitt said in early February 2025 that Musk would determine if his DOGE work presented a conflict of interest. During a February 11 press conference featuring Musk and Trump in the Oval Office, Musk responded to a question about his potential conflict of interest by claiming that "all his team's efforts were being made public on DOGE's social media accounts and website." CNN host Anderson Cooper noted that: Musk has shown opposition to transparency by claiming that reporters investigating Musk's DOGE workers were committing crimes; that Musk himself has not made his conflict-of-interest forms public, and the White House says he won't have to; and that the statements issued on the DOGE X social media account are no more than "press releases". Later that same day, Trump fired USAID Inspector General Paul K. Martin, one day after Martin had issued a report finding that $489 million in food was at risk of spoilage because of the Trump administration's efforts to shutter that agency. A ProPublica investigation found that DOGE staffer Gavin Kliger held up to $365,000 in shares of companies that could benefit from mass firings he oversaw at the Consumer Financial Protection Bureau; the White House denied Kliger's involvement in the mass firings. Experts on government ethics described his stock ownership as a conflict of interest. The "freeze of government function" was described as a coup d'état by Seth Masket, a professor of political science at the University of Denver, because "Musk is a private citizen taking control of established government offices." He notes that Musk has no role in government and questions the validity of DOGE, which is not a federal executive department, assuming power over established government agencies. Author Jeet Heer argued in The Nation that the actions of DOGE were a "time-honored revolutionary tactic of developing dual power in order to seize control" and constituted a coup. Paul Krugman, an economist and columnist, stated on February 3 that the actions of DOGE might have as of that date constituted "what amounts to a 21st-century coup", and that he would update his opinion later. The Guardian stated that it agreed with Krugman. The concept of DOGE also echoes earlier proposals like Curtis Yarvin's RAGE (retire all government employees), which advocates for the dismantling or "reboot" of the federal government. Much like DOGE, Yarvin's plan is rooted in a vision of a "radically gutted" government bureaucracy, but it goes even further in calling for the replacement of democracy with a more business-minded, authoritarian system, such as a dictatorship headed by a "CEO Monarch". Yarvin's ideas, which align with a broader neoreactionary philosophy, have found a significant following among certain conservative circles, with figures like Elon Musk and JD Vance appearing to embrace similar principles. The parallels between RAGE and DOGE raise concerns among critics, who argue that the push to reduce the size of the federal government isn't about efficiency, but rather serves to empower corporate elites and remove internal resistance to unitary executive power, especially from those with more democratic or liberal inclinations. Donald Moynihan, a professor of public policy at the University of Michigan, called Musk and DOGE's actions "concerning" and "unprecedented". Moynihan worries that Musk and his group, not really public officials, had been able to access sensitive government data, and that Congress had very little ability to monitor and intervene. He also added that "Musk's access to Treasury payment systems could give him undue influence over the federal budget at a time when there is a looming debt-ceiling crisis." During a news conference at the Capitol on February 3, 2025, Senator Patty Murray (D-WA), the vice chair of the Senate Appropriations Committee, stated that Musk and his team were breaking the law. Murray stated that Musk was an "unelected, unaccountable billionaire with expansive conflicts of interest, deep ties to China" and accused him of hijacking the nation's financial systems and its ability to pay. DOGE had sought to control the digital systems of many US agencies. This poses security risks on many system vulnerabilities: In April the DOGE social account posted about saving a little over $1 million by replacing magnetic tapes by digital backups, creating archival and security risks according to the community notes and experts. Allison Stanger argues that an artificial intelligence (AI) company (like xAI or Cognition AI) that accesses government data without public accountability could pose a threat. Training on large and longitudinal real data treatments, outcomes and costs across diverse population could topple the medical or the insurance industry and influence health care policy. An AI company with access to USDT data that tracks real-time transactions and money flows could help develop economic and financial forecasting models that would give an investment edge. "A private company with exclusive access to infrastructure data", Stranger contends, "could allow the company to develop "smart city" systems that city governments would become dependent on, effectively privatizing aspects of urban governance". According to a Washington Post article, an official stated that Musk has a project of replacing the human workforce with artificial intelligence. Computer scientist Bruce Schneier dismissed Musk's alleged project as "cyber utopianism". Richard Fourno, assistant director at University of Maryland Baltimore County Cybersecurity Institute, finds DOGE's activities, with little oversight over its employees' operational competence, "create conditions that are ideal for cybersecurity or data privacy incidents that affect the entire nation". James Goldgeier, Professor of International Relations at American University, and Elizabeth N. Saunders, Professor of Political Science at Columbia University, argue that "Musk's activities present a national security nightmare" Employees from FAA's National Airspace System Defense Program have been notified of their termination by email from an Outlook address; the program manages long-range detection radars that secure the country's borders. Some of the fired FAA employees were working on a system announced by the Air Force in 2023 and partially funded by the Defense Department to protect Hawaii from cruise missiles. One fired employee whose position was supposed to be exempt from probationary firings due to the national security-related work he was doing believes he was targeted because of personal Facebook posts he made criticizing Musk's companies X and Tesla. Hundreds of National Nuclear Security Administration workers have been fired; the administration is trying to hire them back. The US Department of Agriculture said it "accidentally" fired "several" employees working on the government's response to the avian flu outbreak and that it will "correct" the situation. Bruce Schneier and Davi Ottenheimer argue that DOGE's hacking creates multiple threats: centralizing information breaks the principle of separation of duties; adding new servers brings new targets; modifying core systems exposes future gaps to be exploited. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Ultraviolet] | [TOKENS: 11070] |
Contents Ultraviolet Ultraviolet radiation or UV is electromagnetic radiation of wavelengths of 100–400 nanometers, shorter than that of visible light, but longer than X-rays. Wavelengths between 10 and 100 nanometers are called extreme ultraviolet and share some properties with soft X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms.: 25–26 Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. These interactions can involve exciting orbital electrons to higher energy states in molecules potentially breaking chemical bonds. In contrast, the main effect of longer wavelength radiation is to excite vibrational or rotational states of these molecules, increasing their temperature.: 28 Short-wave ultraviolet light is ionizing radiation. Consequently, short-wave UV damages DNA and sterilizes surfaces with which it comes into contact. For humans, suntan and sunburn are familiar effects of exposure of the skin to UV, along with an increased risk of skin cancer. The amount of UV radiation produced by the Sun means that the Earth would not be able to sustain life on dry land if most of that light were not filtered out by the atmosphere. More energetic, shorter-wavelength "extreme" UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground. However, UV (specifically, UVB) is also responsible for the formation of vitamin D in most land vertebrates, including humans. The UV spectrum, thus, has effects both beneficial and detrimental to life. The lower wavelength limit of the visible spectrum is conventionally taken as 400 nm. Although ultraviolet rays are not generally visible to humans, 400 nm is not a sharp cutoff, with shorter and shorter wavelengths becoming less and less visible in this range. Insects, birds, and some mammals can see near-UV (NUV), i.e., somewhat shorter wavelengths than what humans can see. Visibility Humans generally cannot use ultraviolet rays for vision. The lens of the human eye and surgically implanted lenses produced since 1986 block most radiation in the near UV wavelength range of 300–400 nm; shorter wavelengths are blocked by the cornea. Humans also lack color receptor adaptations for ultraviolet rays. The photoreceptors of the retina are sensitive to near-UV but the lens does not focus this light properly, causing UV light bulbs to look fuzzy. People lacking a lens (a condition known as aphakia) perceive near-UV as whitish-blue or whitish-violet. Near-UV radiation is visible to insects, some mammals, and some birds. Birds have a fourth color receptor for ultraviolet rays; this, coupled with eye structures that transmit more UV gives smaller birds "true" UV vision. History and discovery "Ultraviolet" means "beyond violet" (from Latin ultra, "beyond"), violet being the color of the highest frequencies of visible light. Ultraviolet has a higher frequency (thus a shorter wavelength) than violet light. UV radiation was discovered in February 1801 when the German physicist Johann Wilhelm Ritter observed that invisible rays just beyond the violet end of the visible spectrum darkened silver chloride-soaked paper more quickly than violet light itself. He announced the discovery in a very brief letter to the Annalen der Physik and later called them "(de-)oxidizing rays" (German: de-oxidierende Strahlen) to emphasize chemical reactivity and to distinguish them from "heat rays", discovered the previous year at the other end of the visible spectrum. The simpler term "chemical rays" was adopted soon afterwards, and remained popular throughout the 19th century, although some said that this radiation was entirely different from light (notably John William Draper, who named them "tithonic rays"). The terms "chemical rays" and "heat rays" were eventually dropped in favor of ultraviolet and infrared radiation, respectively. In 1878, the sterilizing effect of short-wavelength light by killing bacteria was discovered. By 1903, the most effective wavelengths were known to be around 250 nm. In 1960, the effect of ultraviolet radiation on DNA was established. The discovery of the ultraviolet radiation with wavelengths below 200 nm, named "vacuum ultraviolet" because it is strongly absorbed by the oxygen in air, was made in 1893 by German physicist Victor Schumann. The division of UV into UVA, UVB, and UVC was decided "unanimously" by a committee of the Second International Congress on Light on August 17th, 1932, at the Castle of Christiansborg in Copenhagen. Subtypes The electromagnetic spectrum of ultraviolet radiation (UVR), defined most broadly as 10–400 nanometers, can be subdivided into a number of ranges recommended by the ISO standard ISO 21348: Several solid-state and vacuum devices have been explored for use in different parts of the UV spectrum. Many approaches seek to adapt visible light-sensing devices, but these can suffer from unwanted response to visible light and various instabilities. Ultraviolet can be detected by suitable photodiodes and photocathodes, which can be tailored to be sensitive to different parts of the UV spectrum. Sensitive UV photomultipliers are available. Spectrometers and radiometers are made for measurement of UV radiation. Silicon detectors are used across the spectrum. Vacuum UV, or VUV, wavelengths (shorter than 200 nm) are strongly absorbed by molecular oxygen in the air, though the longer wavelengths around 150–200 nm can propagate through nitrogen. Scientific instruments can, therefore, use this spectral range by operating in an oxygen-free atmosphere (pure nitrogen, or argon for shorter wavelengths), without the need for costly vacuum chambers. Significant examples include 193-nm photolithography equipment (for semiconductor manufacturing) and circular dichroism spectrometers. Technology for VUV instrumentation was largely driven by solar astronomy for many decades. While optics can be used to remove unwanted visible light that contaminates the VUV, in general, detectors can be limited by their response to non-VUV radiation, and the development of solar-blind devices has been an important area of research. Wide-gap solid-state devices or vacuum devices with high-cutoff photocathodes can be attractive compared to silicon diodes. Extreme UV (EUV or sometimes XUV) is characterized by a transition in the physics of interaction with matter.: 2 Wavelengths longer than about 30 nm interact mainly with the outer valence electrons of atoms, while wavelengths shorter than that interact mainly with inner-shell electrons and nuclei. The long end of the EUV spectrum is set by a prominent He+ spectral line at 30.4 nm. EUV is strongly absorbed by most known materials, but synthesizing multilayer optics that reflect up to about 50% of EUV radiation at normal incidence is possible. This technology was pioneered by the NIXT and MSSTA sounding rockets in the 1990s, and it has been used to make telescopes for solar imaging. See also the Extreme Ultraviolet Explorer satellite.[citation needed] Some sources use the distinction of "hard UV" and "soft UV". For instance, in the case of astrophysics, the boundary may be at the Lyman limit (wavelength 91.2 nm, the energy needed to ionise a hydrogen atom from its ground state), with "hard UV" being more energetic; the same terms may also be used in other fields, such as cosmetology, optoelectronic, etc. The numerical values of the boundary between hard/soft, even within similar scientific fields, do not necessarily coincide; for example, one applied-physics publication used a boundary of 190 nm between hard and soft UV regions. Solar ultraviolet Very hot objects emit UV radiation (see black-body radiation). The Sun emits ultraviolet radiation at all wavelengths, including the extreme ultraviolet where it crosses into X-rays at 10 nm. Extremely hot stars (such as O- and B-type) emit proportionally more UV radiation than the Sun. Sunlight in space at the top of Earth's atmosphere (see solar constant) is composed of about 50% infrared light, 40% visible light, and 10% ultraviolet light, for a total intensity of about 1400 W/m2 in vacuum. The atmosphere blocks about 77% of the Sun's UV, when the Sun is highest in the sky (at zenith), with absorption increasing at shorter UV wavelengths. At ground level with the sun at zenith, sunlight is 44% visible light, 3% ultraviolet, and the remainder infrared. Of the ultraviolet radiation that reaches the Earth's surface, more than 95% is the longer wavelengths of UVA, with the small remainder UVB. Almost no UVC reaches the Earth's surface. The fraction of UVA and UVB which remains in UV radiation after passing through the atmosphere is heavily dependent on cloud cover and atmospheric conditions. On "partly cloudy" days, patches of blue sky showing between clouds are also sources of (scattered) UVA and UVB, which are produced by Rayleigh scattering in the same way as the visible blue light from those parts of the sky. UVB also plays a major role in plant development, as it affects most of the plant hormones. During total overcast, the amount of absorption due to clouds is heavily dependent on the thickness of the clouds and latitude, with no clear measurements correlating specific thickness and absorption of UVA and UVB. The shorter bands of UVC, as well as even more-energetic UV radiation produced by the Sun, are absorbed by oxygen and generate the ozone in the ozone layer when single oxygen atoms produced by UV photolysis of dioxygen react with more dioxygen. The ozone layer is especially important in blocking most UVB and the remaining part of UVC not already blocked by ordinary oxygen in air.[citation needed] Blockers, absorbers, and windows Ultraviolet absorbers are molecules used in organic materials (polymers, paints, etc.) to absorb UV radiation to reduce the UV degradation (photo-oxidation) of a material. The absorbers can themselves degrade over time, so monitoring of absorber levels in weathered materials is necessary.[citation needed] In sunscreen, ingredients that absorb UVA/UVB rays, such as avobenzone, oxybenzone and octyl methoxycinnamate, are organic chemical absorbers or "blockers". They are contrasted with inorganic absorbers/"blockers" of UV radiation such as titanium dioxide and zinc oxide. For clothing, the ultraviolet protection factor (UPF) represents the ratio of sunburn-causing UV without and with the protection of the fabric, similar to sun protection factor (SPF) ratings for sunscreen.[citation needed] Standard summer fabrics have UPFs around 6, which means that about 20% of UV will pass through. Suspended nanoparticles in stained-glass prevent UV rays from causing chemical reactions that change image colors. A set of stained-glass color-reference chips is planned to be used to calibrate the color cameras for the 2019 ESA Mars rover mission, since they will remain unfaded by the high level of UV present at the surface of Mars. Common soda–lime glass, such as window glass, is partially transparent to UVA, but is opaque to shorter wavelengths, passing about 90% of the light above 350 nm, but blocking over 90% of the light below 300 nm. A study found that car windows allow 3–4% of ambient UV to pass through, especially if the UV was greater than 380 nm. Other types of car windows can reduce transmission of UV that is greater than 335 nm. Fused quartz, depending on quality, can be transparent even to vacuum UV wavelengths. Crystalline quartz and some crystals such as CaF2 and MgF2 transmit well down to 150 nm or 160 nm wavelengths. Wood's glass is a deep violet-blue barium-sodium silicate glass with about 9% nickel(II) oxide developed during World War I to block visible light for covert communications.[citation needed] It allows both infrared daylight and ultraviolet night-time communications by being transparent between 320 nm and 400 nm and also the longer infrared and just-barely-visible red wavelengths.[citation needed] Its maximum UV transmission is at 365 nm, one of the wavelengths of mercury lamps.[citation needed] Artificial sources A black light lamp emits long-wave UVA radiation and little visible light. Fluorescent black light lamps work similarly to other fluorescent lamps, but use a phosphor on the inner tube surface which emits UVA radiation instead of visible light. Some lamps use a deep-bluish-purple Wood's glass optical filter that blocks almost all visible light with wavelengths longer than 400 nanometers. The purple glow given off by these tubes is not the ultraviolet itself, but visible purple light from mercury's 404 nm spectral line which escapes being filtered out by the coating. Other black lights use plain glass instead of the more expensive Wood's glass, so they appear light-blue to the eye when operating.[citation needed] Incandescent black lights are also produced, using a filter coating on the envelope of an incandescent bulb that absorbs visible light (see section below). These are cheaper but very inefficient, emitting only a small fraction of a percent of their power as UV. Mercury-vapor black lights in ratings up to 1 kW with UV-emitting phosphor and an envelope of Wood's glass are used for theatrical and concert displays.[citation needed] Black lights are used in applications in which extraneous visible light must be minimized; mainly to observe fluorescence, the colored glow that many substances give off when exposed to UV light. UVA / UVB emitting bulbs are also sold for other special purposes, such as tanning lamps and reptile-husbandry.[citation needed] Mercury-vapor lamps consisting of fused quartz tubes filled mercury and Argon, emit ultraviolet light with two peaks in the UVC band at 253.7 nm and 185 nm as well as some visible light. From 85% to 90% of the UV produced by these lamps is at 253.7 nm which very effective as a germicide. The lamps also produce UV at 185 nm effective in producing ozone with additional germicide effects. Such tubes have two or three times the UVC power of a regular fluorescent lamp tube. These low-pressure lamps have a typical efficiency of approximately 30–40%, meaning that for every 100 watts of electricity consumed by the lamp, they will produce approximately 30–40 watts of total UV output. They also emit bluish-white visible light, due to mercury's other spectral lines. These "germicidal" lamps are used extensively for disinfection of surfaces in laboratories and food-processing industries. 'Black light' incandescent lamps are also made from an incandescent light bulb with a filter coating which absorbs most visible light. Halogen lamps with fused quartz envelopes are used as inexpensive UV light sources in the near UV range, from 400 to 300 nm, in some scientific instruments. Due to its black-body spectrum a filament light bulb is a very inefficient ultraviolet source, emitting only a fraction of a percent of its energy as UV, as explained by the black body spectrum. Specialized UV gas-discharge lamps containing different gases produce UV radiation at particular spectral lines for scientific purposes. Argon and deuterium arc lamps are often used as stable sources, either windowless or with various windows such as magnesium fluoride. These are often the emitting sources in UV spectroscopy equipment for chemical analysis.[citation needed] Other UV sources with more continuous emission spectra include xenon arc lamps (commonly used as sunlight simulators), deuterium arc lamps, mercury-xenon arc lamps, and metal-halide arc lamps.[citation needed] The excimer lamp, a UV source developed in the early 2000s, is seeing increasing use in scientific fields. It has the advantages of high-intensity, high efficiency, and operation at a variety of wavelength bands into the vacuum ultraviolet.[citation needed] Light-emitting diodes (LEDs) can be manufactured to emit radiation in the ultraviolet range. In 2019, following significant advances over the preceding five years, UVA LEDs of 365 nm and longer wavelength were available, with efficiencies of 50% at 1.0 W output. Currently, the most common types of UV LEDs are in 395 nm and 365 nm wavelengths, both of which are in the UVA spectrum. The rated wavelength is the peak wavelength that the LEDs put out, but light at both higher and lower wavelengths are present. The cheaper and more common 395 nm UV LEDs are much closer to the visible spectrum, and give off a purple color. Other UV LEDs deeper into the spectrum do not emit as much visible light. LEDs are used for applications such as UV curing applications, charging glow-in-the-dark objects such as paintings or toys, and lights for detecting counterfeit money and bodily fluids. UV LEDs are also used in digital print applications and inert UV curing environments. As technological advances beginning in the early 2000s have improved their output and efficiency, they have become increasingly viable alternatives to more traditional UV lamps for use in UV curing applications, and the development of new UV LED curing systems for higher-intensity applications is a major subject of research in the field of UV curing technology. UVC LEDs are developing rapidly, but may require testing to verify effective disinfection. Citations for large-area disinfection are for non-LED UV sources known as germicidal lamps. Also, they are used as line sources to replace deuterium lamps in liquid chromatography instruments. Gas lasers, laser diodes, and solid-state lasers can be manufactured to emit ultraviolet rays, and lasers are available that cover the entire UV range. The nitrogen gas laser uses electronic excitation of nitrogen molecules to emit a beam that is mostly UV. The strongest ultraviolet lines are at 337.1 nm and 357.6 nm in wavelength. Another type of high-power gas lasers are excimer lasers. They are widely used lasers emitting in ultraviolet and vacuum ultraviolet wavelength ranges. Presently, UV argon-fluoride excimer lasers operating at 193 nm are routinely used in integrated circuit production by photolithography. The current[timeframe?] wavelength limit of production of coherent UV is about 126 nm, characteristic of the Ar2* excimer laser.[citation needed] Direct UV-emitting laser diodes are available at 375 nm. UV diode-pumped solid state lasers have been demonstrated using cerium-doped lithium strontium aluminum fluoride crystals (Ce:LiSAF), a process developed in the 1990s at Lawrence Livermore National Laboratory. Wavelengths shorter than 325 nm are commercially generated in diode-pumped solid-state lasers. Ultraviolet lasers can also be made by applying frequency conversion to lower-frequency lasers. Ultraviolet lasers have applications in industry (laser engraving), medicine (dermatology, and keratectomy), chemistry (MALDI), free-space optical communication, computing (optical storage), and manufacture of integrated circuits. The vacuum ultraviolet (V‑UV) band (100–200 nm) can be generated by non-linear 4 wave mixing in gases by sum or difference frequency mixing of 2 or more longer wavelength lasers. The generation is generally done in gasses (e.g. krypton, hydrogen which are two-photon resonant near 193 nm) or metal vapors (e.g. magnesium). By making one of the lasers tunable, the V‑UV can be tuned. If one of the lasers is resonant with a transition in the gas or vapor then the V‑UV production is intensified. However, resonances also generate wavelength dispersion, and thus the phase matching can limit the tunable range of the 4 wave mixing. Difference frequency mixing (i.e., f1 + f2 − f3) has an advantage over sum frequency mixing because the phase matching can provide greater tuning. In particular, difference frequency mixing two photons of an ArF (193 nm) excimer laser with a tunable visible or near IR laser in hydrogen or krypton provides resonantly enhanced tunable V‑UV covering from 100 nm to 200 nm. Practically, the lack of suitable gas / vapor cell window materials above the lithium fluoride cut-off wavelength limit the tuning range to longer than about 110 nm. Tunable V‑UV wavelengths down to 75 nm was achieved using window-free configurations. Lasers have been used to indirectly generate non-coherent extreme UV (E‑UV) radiation at 13.5 nm for extreme ultraviolet lithography. The E‑UV is not emitted by the laser, but rather by electron transitions in an extremely hot tin or xenon plasma, which is excited by an excimer laser. This technique does not require a synchrotron, yet can produce UV at the edge of the X‑ray spectrum. Synchrotron light sources can also produce all wavelengths of UV, including those at the boundary of the UV and X‑ray spectra at 10 nm.[citation needed] Human health-related effects The impact of ultraviolet radiation on human health has implications for the risks and benefits of sun exposure and is also implicated in issues such as fluorescent lamps and health. Getting too much sun exposure can be harmful, but in moderation, sun exposure is beneficial. UV (specifically, UVB) causes the body to produce vitamin D, which is essential for life. Humans need some UV radiation to maintain adequate vitamin D levels. According to the World Health Organization: There is no doubt that a little sunlight is good for you! But 5–15 minutes of casual sun exposure of hands, face and arms two to three times a week during the summer months is sufficient to keep your vitamin D levels high. Vitamin D can also be obtained from food and supplementation. Excess sun exposure produces harmful effects, however. UV rays also treat certain skin conditions. Modern phototherapy has been used to successfully treat psoriasis, eczema, jaundice, vitiligo, atopic dermatitis, and localized scleroderma. In addition, UV radiation, in particular UVB radiation, has been shown to induce cell cycle arrest in keratinocytes, the most common type of skin cell. As such, sunlight therapy can be a candidate for treatment of conditions such as psoriasis and exfoliative cheilitis, conditions in which skin cells divide more rapidly than usual or necessary. In humans, excessive exposure to UV radiation can result in acute and chronic harmful effects on the eye's dioptric system and retina. The risk is elevated at high altitudes and people living in high latitude areas where snow covers the ground right into early summer and sun positions even at zenith are low, are particularly at risk. Skin, the circadian system, and the immune system can also be affected. The differential effects of various wavelengths of light on the human cornea and skin are sometimes called the "erythemal action spectrum". The action spectrum shows that UVA does not cause immediate reaction, but rather UV begins to cause photokeratitis and skin redness (with lighter skinned individuals being more sensitive) at wavelengths starting near the beginning of the UVB band at 315 nm, and rapidly increasing to 300 nm. The skin and eyes are most sensitive to damage by UV at 265–275 nm, which is in the lower UVC band. At still shorter wavelengths of UV, damage continues to happen, but the overt effects are not as great with so little penetrating the atmosphere. The WHO-standard ultraviolet index is a widely publicized measurement of total strength of UV wavelengths that cause sunburn on human skin, by weighting UV exposure for action spectrum effects at a given time and location. This standard shows that most sunburn happens due to UV at wavelengths near the boundary of the UVA and UVB bands.[citation needed] Overexposure to UVB radiation not only can cause sunburn but also some forms of skin cancer. However, the degree of redness and eye irritation (which are largely not caused by UVA) do not predict the long-term effects of UV, although they do mirror the direct damage of DNA by ultraviolet. All bands of UV radiation damage collagen fibers and accelerate aging of the skin. Both UVA and UVB destroy vitamin A in skin, which may cause further damage. UVB radiation can cause direct DNA damage. This cancer connection is one reason for concern about ozone depletion and the ozone hole. The most deadly form of skin cancer, melanoma, is mostly caused by DNA damage independent from UVA radiation. This can be seen from the absence of a direct UV signature mutation in 92% of all melanoma. Occasional overexposure and sunburn are probably greater risk factors for melanoma than long-term moderate exposure. UVC is the highest-energy, most-dangerous type of ultraviolet radiation, and causes adverse effects that can variously be mutagenic or carcinogenic. In the past, UVA was considered not harmful or less harmful than UVB, but today it is known to contribute to skin cancer via indirect DNA damage (free radicals such as reactive oxygen species). UVA can generate highly reactive chemical intermediates, such as hydroxyl and oxygen radicals, which in turn can damage DNA. The DNA damage caused indirectly to skin by UVA consists mostly of single-strand breaks in DNA, while the damage caused by UVB includes direct formation of thymine dimers or cytosine dimers and double-strand DNA breakage. UVA is immunosuppressive for the entire body (accounting for a large part of the immunosuppressive effects of sunlight exposure), and is mutagenic for basal cell keratinocytes in skin. UVB photons can cause direct DNA damage. UVB radiation excites DNA molecules in skin cells, causing aberrant covalent bonds to form between adjacent pyrimidine bases, producing a dimer. Most UV-induced pyrimidine dimers in DNA are removed by the process known as nucleotide excision repair that employs about 30 different proteins. Those pyrimidine dimers that escape this repair process can induce a form of programmed cell death (apoptosis) or can cause DNA replication errors leading to mutation.[citation needed] UVB damages mRNA This triggers a fast pathway that leads to inflammation of the skin and sunburn. mRNA damage initially triggers a response in ribosomes though a protein known as ZAK-alpha in a ribotoxic stress response. This response acts as a cell surveillance system. Following this detection of RNA damage leads to inflammatory signaling and recruitment of immune cells. This, not DNA damage (which is slower to detect) results in UVB skin inflammation and acute sunburn. As a defense against UV radiation, the amount of the brown pigment melanin in the skin increases when exposed to moderate (depending on skin type) levels of radiation; this is commonly known as a sun tan. The purpose of melanin is to absorb UV radiation and dissipate the energy as harmless heat, protecting the skin against both direct and indirect DNA damage from the UV. UVA gives a quick tan that lasts for days by oxidizing melanin that was already present and triggers the release of the melanin from melanocytes. UVB yields a tan that takes roughly 2 days to develop because it stimulates the body to produce more melanin.[citation needed] Medical organizations recommend that patients protect themselves from UV radiation by using sunscreen. Five sunscreen ingredients have been shown to protect mice against skin tumors. However, some sunscreen chemicals produce potentially harmful substances if they are illuminated while in contact with living cells. The amount of sunscreen that penetrates into the lower layers of the skin may be large enough to cause damage. Sunscreen reduces the direct DNA damage that causes sunburn, by blocking UVB, and the usual SPF rating indicates how effectively this radiation is blocked. SPF is, therefore, also called UVB-PF, for "UVB protection factor". This rating, however, offers no data about important protection against UVA, which does not primarily cause sunburn but is still harmful, since it causes indirect DNA damage and is also considered carcinogenic. Several studies suggest that the absence of UVA filters may be the cause of the higher incidence of melanoma found in sunscreen users compared to non-users. Some sunscreen lotions contain titanium dioxide, zinc oxide, and avobenzone, which help protect against UVA rays. The photochemical properties of melanin make it an excellent photoprotectant. However, sunscreen chemicals cannot dissipate the energy of the excited state as efficiently as melanin and therefore, if sunscreen ingredients penetrate into the lower layers of the skin, the amount of reactive oxygen species may be increased. The amount of sunscreen that penetrates through the stratum corneum may or may not be large enough to cause damage. In an experiment by Hanson et al. that was published in 2006, the amount of harmful reactive oxygen species (ROS) was measured in untreated and in sunscreen treated skin. In the first 20 minutes, the film of sunscreen had a protective effect and the number of ROS species was smaller. After 60 minutes, however, the amount of absorbed sunscreen was so high that the amount of ROS was higher in the sunscreen-treated skin than in the untreated skin. The study indicates that sunscreen must be reapplied within 2 hours in order to prevent UV light from penetrating to sunscreen-infused live skin cells. Ultraviolet radiation can aggravate several skin conditions and diseases, including systemic lupus erythematosus, Sjögren's syndrome, Sinear Usher syndrome, rosacea, dermatomyositis, Darier's disease, Kindler–Weary syndrome and Porokeratosis. The eye is most sensitive to damage by UV in the lower UVC band at 265–275 nm. Radiation of this wavelength is almost absent from sunlight at the surface of the Earth but is emitted by artificial sources such as the electrical arcs employed in arc welding. Unprotected exposure to these sources can cause "welder's flash" or "arc eye" (photokeratitis) and can lead to cataracts, pterygium and pinguecula formation. To a lesser extent, UVB in sunlight from 310 to 280 nm also causes photokeratitis ("snow blindness"), and the cornea, the lens, and the retina can be damaged. Protective eyewear is beneficial to those exposed to ultraviolet radiation. Since light can reach the eyes from the sides, full-coverage eye protection is usually warranted if there is an increased risk of exposure, as in high-altitude mountaineering. Mountaineers are exposed to higher-than-ordinary levels of UV radiation, both because there is less atmospheric filtering and because of reflection from snow and ice. Ordinary, untreated eyeglasses give some protection. Most plastic lenses give more protection than glass lenses, because, as noted above, glass is transparent to UVA and the common acrylic plastic used for lenses is less so. Some plastic lens materials, such as polycarbonate, inherently block most UV. Degradation of polymers, pigments and dyes UV degradation is one form of polymer degradation that affects plastics exposed to sunlight. The problem appears as discoloration or fading, cracking, loss of strength or disintegration. The effects of attack increase with exposure time and sunlight intensity. The addition of UV absorbers inhibits the effect. Sensitive polymers include thermoplastics and speciality fibers like aramids. UV absorption leads to chain degradation and loss of strength at sensitive points in the chain structure. Aramid rope must be shielded with a sheath of thermoplastic if it is to retain its strength.[citation needed] Many pigments and dyes absorb UV and change colour, so paintings and textiles may need extra protection both from sunlight and fluorescent lamps, two common sources of UV radiation. Window glass absorbs some harmful UV, but valuable artifacts need extra shielding. Many museums place black curtains over watercolour paintings and ancient textiles, for example. Since watercolours can have very low pigment levels, they need extra protection from UV. Various forms of picture framing glass, including acrylics (plexiglass), laminates, and coatings, offer different degrees of UV (and visible light) protection. Applications Because of its ability to cause chemical reactions and excite fluorescence in materials, ultraviolet radiation has a number of applications. The following table gives some uses of specific wavelength bands in the UV spectrum. Photographic film responds to ultraviolet radiation but the glass lenses of cameras usually block radiation shorter than 350 nm. Slightly yellow UV-blocking filters are often used for outdoor photography to prevent unwanted bluing and overexposure by UV rays. For photography in the near UV, special filters may be used. Photography with wavelengths shorter than 350 nm requires special quartz lenses which do not absorb the radiation. Digital cameras sensors may have internal filters that block UV to improve color rendition accuracy. Sometimes these internal filters can be removed, or they may be absent, and an external visible-light filter prepares the camera for near-UV photography. A few cameras are designed for use in the UV. Photography by reflected ultraviolet radiation is useful for medical, scientific, and forensic investigations, in applications as widespread as detecting bruising of skin, alterations of documents, or restoration work on paintings. Photography of the fluorescence produced by ultraviolet illumination uses visible wavelengths of light.[citation needed] In ultraviolet astronomy, measurements are used to discern the chemical composition of the interstellar medium, and the temperature and composition of stars. Because the ozone layer blocks many UV frequencies from reaching telescopes on the surface of the Earth, most UV observations are made from space. Corona discharge on electrical apparatus can be detected by its ultraviolet emissions. Corona causes degradation of electrical insulation and emission of ozone and nitrogen oxide. EPROMs (Erasable Programmable Read-Only Memory) are erased by exposure to UV radiation. These modules have a transparent (quartz) window on the top of the chip that allows the UV radiation in. Colorless fluorescent dyes that emit blue light under UV are added as optical brighteners to paper and fabrics. The blue light emitted by these agents counteracts yellow tints that may be present and causes the colors and whites to appear whiter or more brightly colored. UV fluorescent dyes that glow in the primary colors are used in paints, papers, and textiles either to enhance color under daylight illumination or to provide special effects when lit with UV lamps. Blacklight paints that contain dyes that glow under UV are used in a number of art and aesthetic applications.[citation needed] To help prevent counterfeiting of currency, or forgery of important documents such as driver's licenses and passports, the paper may include a UV watermark or fluorescent multicolor fibers that are visible under ultraviolet light. Postage stamps are tagged with a phosphor that glows under UV rays to permit automatic detection of the stamp and facing of the letter. UV fluorescent dyes are used in many applications (for example, biochemistry and forensics). Some brands of pepper spray will leave an invisible chemical (UV dye) that is not easily washed off on a pepper-sprayed attacker, which would help police identify the attacker later. In some types of nondestructive testing UV stimulates fluorescent dyes to highlight defects in a broad range of materials. These dyes may be carried into surface-breaking defects by capillary action (liquid penetrant inspection) or they may be bound to ferrite particles caught in magnetic leakage fields in ferrous materials (magnetic particle inspection). UV is an investigative tool at the crime scene helpful in locating and identifying bodily fluids such as semen, blood, and saliva. For example, ejaculated fluids or saliva can be detected by high-power UV sources, irrespective of the structure or colour of the surface the fluid is deposited upon. UV–vis microspectroscopy is also used to analyze trace evidence, such as textile fibers and paint chips, as well as questioned documents. Other applications include the authentication of various collectibles and art, and detecting counterfeit currency. Even materials not specially marked with UV sensitive dyes may have distinctive fluorescence under UV exposure or may fluoresce differently under short-wave versus long-wave ultraviolet. Using multi-spectral imaging it is possible to read illegible papyrus, such as the burned papyri of the Villa of the Papyri or of Oxyrhynchus, or the Archimedes palimpsest. The technique involves taking pictures of the illegible document using different filters in the infrared or ultraviolet range, finely tuned to capture certain wavelengths of light. Thus, the optimum spectral portion can be found for distinguishing ink from paper on the papyrus surface. Simple NUV sources can be used to highlight faded iron-based ink on vellum. Ultraviolet helps detect organic material deposits that remain on surfaces where periodic cleaning and sanitizing may have failed. It is used in the hotel industry, manufacturing, and other industries where levels of cleanliness or contamination are inspected. Perennial news features for many television news organizations involve an investigative reporter using a similar device to reveal unsanitary conditions in hotels, public toilets, hand rails, and such. UV/Vis spectroscopy is widely used as a technique in chemistry to analyze chemical structure, the most notable one being conjugated systems. UV radiation is often used to excite a given sample where the fluorescent emission is measured with a spectrofluorometer. In biological research, UV radiation is used for quantification of nucleic acids or proteins. In environmental chemistry, UV radiation could also be used to detect Contaminants of emerging concern in water samples. In pollution control applications, ultraviolet analyzers are used to detect emissions of nitrogen oxides, sulfur compounds, mercury, and ammonia, for example in the flue gas of fossil-fired power plants. Ultraviolet radiation can detect thin sheens of spilled oil on water, either by the high reflectivity of oil films at UV wavelengths, fluorescence of compounds in oil, or by absorbing of UV created by Raman scattering in water. UV absorbance can also be used to quantify contaminants in wastewater. Most commonly used 254 nm UV absorbance is generally used as a surrogate parameters to quantify NOM. Another form of light-based detection uses an excitation-emission matrix (EEM) to detect and identify contaminants based on their fluorescence properties. EEM could be used to discriminate different groups of NOM based on the difference in light emission and excitation of fluorophores. NOMs with certain molecular structures are reported to have fluorescent properties in a wide range of excitation/emission wavelengths. Ultraviolet lamps are also used as part of the analysis of some minerals and gems. In general, ultraviolet detectors use either a solid-state device, such as one based on silicon carbide or aluminium nitride, or a gas-filled tube as the sensing element. UV detectors that are sensitive to UV in any part of the spectrum respond to irradiation by sunlight and artificial light. A burning hydrogen flame, for instance, radiates strongly in the 185- to 260-nanometer range and only very weakly in the IR region, whereas a coal fire emits very weakly in the UV band yet very strongly at IR wavelengths; thus, a fire detector that operates using both UV and IR detectors is more reliable than one with a UV detector alone. Virtually all fires emit some radiation in the UVC band, whereas the Sun's radiation at this band is absorbed by the Earth's atmosphere. The result is that the UV detector is "solar blind", meaning it will not cause an alarm in response to radiation from the Sun, so it can easily be used both indoors and outdoors. UV detectors are sensitive to most fires, including hydrocarbons, metals, sulfur, hydrogen, hydrazine, and ammonia. Arc welding, electrical arcs, lightning, X-rays used in nondestructive metal testing equipment (though this is highly unlikely), and radioactive materials can produce levels that will activate a UV detection system. The presence of UV-absorbing gases and vapors will attenuate the UV radiation from a fire, adversely affecting the ability of the detector to detect flames. Likewise, the presence of an oil mist in the air or an oil film on the detector window will have the same effect. Ultraviolet radiation is used for very fine resolution photolithography, a procedure wherein a chemical called a photoresist is exposed to UV radiation that has passed through a mask. The exposure causes chemical reactions to occur in the photoresist. After removal of unwanted photoresist, a pattern determined by the mask remains on the sample. Steps may then be taken to "etch" away, deposit on or otherwise modify areas of the sample where no photoresist remains. Photolithography is used in the manufacture of semiconductors, integrated circuit components, and printed circuit boards. Photolithography processes used to fabricate electronic integrated circuits presently use 193 nm UV and are experimentally using 13.5 nm UV for extreme ultraviolet lithography. Electronic components that require clear transparency for light to exit or enter (photovoltaic panels and sensors) can be potted using acrylic resins that are cured using UV energy. The advantages are low VOC emissions and rapid curing. Certain inks, coatings, and adhesives are formulated with photoinitiators and resins. When exposed to UV light, polymerization occurs, and so the adhesives harden or cure, usually within a few seconds. Applications include glass and plastic bonding, optical fiber coatings, the coating of flooring, UV coating and paper finishes in offset printing, dental fillings, hydrophobic light-activated adhesive, and decorative fingernail "gels". UV sources for UV curing applications include UV lamps, UV LEDs, and excimer flash lamps. Fast processes such as flexo or offset printing require high-intensity light focused via reflectors onto a moving substrate and medium so high-pressure Hg (mercury) or Fe (iron, doped)-based bulbs are used, energized with electric arcs or microwaves. Lower-power fluorescent lamps and LEDs can be used for static applications. Small high-pressure lamps can have light focused and transmitted to the work area via liquid-filled or fiber-optic light guides. The impact of UV on polymers is used for modification of the (roughness and hydrophobicity) of polymer surfaces. For example, a poly(methyl methacrylate) surface can be smoothed by vacuum ultraviolet. UV radiation is useful in preparing low-surface-energy polymers for adhesives. Polymers exposed to UV will oxidize, thus raising the surface energy of the polymer. Once the surface energy of the polymer has been raised, the bond between the adhesive and the polymer is stronger. UV-C light is used in air conditioning systems as a method of improving indoor air quality by disinfecting the air and preventing microbial growth. UV-C light is effective at killing or inactivating harmful microorganisms, such as bacteria, viruses, mold, and mildew. When integrated into an air conditioning system, the ultraviolet light is typically placed in areas like the air handler or near the evaporator coil. In air conditioning systems, UV-C light works by irradiating the airflow within the system, killing or neutralizing harmful microorganisms before they are recirculated into the indoor environment. The effectiveness of it in air conditioning systems depends on factors such as the intensity of the light, the duration of exposure, airflow speed, and the cleanliness of system components. Using a catalytic chemical reaction from titanium dioxide and UVC exposure, oxidation of organic matter converts pathogens, pollens, and mold spores into harmless inert byproducts. However, the reaction of titanium dioxide and UVC is not a straight path. Several hundreds of reactions occur prior to the inert byproducts stage and can hinder the resulting reaction creating formaldehyde, aldehyde, and other VOC's en route to a final stage. Thus, the use of titanium dioxide and UVC requires very specific parameters for a successful outcome. The cleansing mechanism of UV is a photochemical process. Contaminants in the indoor environment are almost entirely organic carbon-based compounds, which break down when exposed to high-intensity UV at 240 to 280 nm. Short-wave ultraviolet radiation can destroy DNA in living microorganisms. UVC's effectiveness is directly related to intensity and exposure time. UV has also been shown to reduce gaseous contaminants such as carbon monoxide and VOCs. UV lamps radiating at 184 and 254 nm can remove low concentrations of hydrocarbons and carbon monoxide if the air is recycled between the room and the lamp chamber. This arrangement prevents the introduction of ozone into the treated air. Likewise, air may be treated by passing by a single UV source operating at 184 nm and passed over iron pentaoxide to remove the ozone produced by the UV lamp. Ultraviolet lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. Commercially available low-pressure mercury-vapor lamps emit about 86% of their radiation at 254 nanometers (nm), with 265 nm being the peak germicidal effectiveness curve. UV at these germicidal wavelengths damage a microorganism's DNA/RNA so that it cannot reproduce, making it harmless, (even though the organism may not be killed). Since microorganisms can be shielded from ultraviolet rays in small cracks and other shaded areas, these lamps are used only as a supplement to other sterilization techniques. UVC LEDs are relatively new to the commercial market and are gaining in popularity.[failed verification] Due to their monochromatic nature (±5 nm)[failed verification] these LEDs can target a specific wavelength needed for disinfection. This is especially important knowing that pathogens vary in their sensitivity to specific UV wavelengths. LEDs are mercury free, instant on/off, and have unlimited cycling throughout the day. Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in municipal drinking water treatment. Many bottlers of spring water use UV disinfection equipment to sterilize their water. Solar water disinfection has been researched for cheaply treating contaminated water using natural sunlight. The UVA irradiation and increased water temperature kill organisms in the water. Ultraviolet radiation is used in several food processes to kill unwanted microorganisms. UV can be used to pasteurize fruit juices by flowing the juice over a high-intensity ultraviolet source. The effectiveness of such a process depends on the UV absorbance of the juice. Pulsed light (PL) is a technique of killing microorganisms on surfaces using pulses of an intense broad spectrum, rich in UVC between 200 and 280 nm. Pulsed light works with xenon flash lamps that can produce flashes several times per second. Disinfection robots use pulsed UV. The antimicrobial effectiveness of filtered far-UVC (222 nm) light on a range of pathogens, including bacteria and fungi showed inhibition of pathogen growth, and since it has lesser harmful effects, it provides essential insights for reliable disinfection in healthcare settings, such as hospitals and long-term care homes. UVC has also been shown to be effective at degrading SARS-CoV-2 virus. Birds, reptiles, insects such as bees, and mammals such as mice, reindeer, dogs, and cats can see near-ultraviolet wavelengths. Many fruits, flowers, and seeds stand out more strongly from the background in ultraviolet wavelengths as compared to human color vision. Scorpions glow or take on a yellow to green color under UV illumination, thus assisting in the control of these arachnids. Many birds have patterns in their plumage that are invisible at usual wavelengths but observable in ultraviolet, and the urine and other secretions of some animals, including dogs, cats, and human beings, are much easier to spot with ultraviolet. Urine trails of rodents can be detected by pest control technicians for proper treatment of infested dwellings. Butterflies use ultraviolet as a communication system for sex recognition and mating behavior. For example, in the Colias eurytheme butterfly, males rely on visual cues to locate and identify females. Instead of using chemical stimuli to find mates, males are attracted to the ultraviolet-reflecting color of female hind wings. In Pieris napi butterflies it was shown that females in northern Finland with less UV-radiation present in the environment possessed stronger UV signals to attract their males than those occurring further south. This suggested that it was evolutionarily more difficult to increase the UV-sensitivity of the eyes of the males than to increase the UV-signals emitted by the females. Many insects use the ultraviolet wavelength emissions from celestial objects as references for flight navigation. A local ultraviolet emitter will normally disrupt the navigation process and will eventually attract the flying insect. The green fluorescent protein (GFP) is often used in genetics as a marker. Many substances, such as proteins, have significant light absorption bands in the ultraviolet that are of interest in biochemistry and related fields. UV-capable spectrophotometers are common in such laboratories. Ultraviolet traps called bug zappers are used to eliminate various small flying insects. They are attracted to the UV and are killed using an electric shock, or trapped once they come into contact with the device. Different designs of ultraviolet radiation traps are also used by entomologists for collecting nocturnal insects during faunistic survey studies. Ultraviolet radiation is helpful in the treatment of skin conditions such as psoriasis and vitiligo. Exposure to UVA, while the skin is hyper-photosensitive, by taking psoralens is an effective treatment for psoriasis. Due to the potential of psoralens to cause damage to the liver, PUVA therapy may be used only a limited number of times over a patient's lifetime. UVB phototherapy does not require additional medications or topical preparations for the therapeutic benefit; only the exposure is needed. However, phototherapy can be effective when used in conjunction with certain topical treatments such as anthralin, coal tar, and vitamin A and D derivatives, or systemic treatments such as methotrexate and Soriatane. Reptiles need UVB for biosynthesis of vitamin D, and other metabolic processes. Specifically cholecalciferol (vitamin D3), which is needed for basic cellular / neural functioning as well as the utilization of calcium for bone and egg production.[citation needed] The UVA wavelength is also visible to many reptiles and might play a significant role in their ability survive in the wild as well as in visual communication between individuals.[citation needed] Therefore, in a typical reptile enclosure, a fluorescent UV a/b source (at the proper strength / spectrum for the species), must be available for many[which?] captive species to survive. Simple supplementation with cholecalciferol (Vitamin D3) will not be enough as there is a complete biosynthetic pathway[which?] that is "leapfrogged" (risks of possible overdoses), the intermediate molecules and metabolites[which?] also play important functions in the animals health.[citation needed] Natural sunlight in the right levels is always going to be superior to artificial sources, but this might not be possible for keepers in different parts of the world.[citation needed] It is a known problem that high levels of output of the UVa part of the spectrum can both cause cellular and DNA damage to sensitive parts of their bodies – especially the eyes where blindness is the result of an improper UVa/b source use and placement photokeratitis.[citation needed] For many keepers there must also be a provision for an adequate heat source this has resulted in the marketing of heat and light "combination" products.[citation needed] Keepers should be careful of these "combination" light/ heat and UVa/b generators, they typically emit high levels of UVa with lower levels of UVb that are set and difficult to control so that animals can have their needs met.[citation needed] A better strategy is to use individual sources of these elements and so they can be placed and controlled by the keepers for the max benefit of the animals. Evolutionary significance The evolution of early reproductive proteins and enzymes is attributed in modern models of evolutionary theory to ultraviolet radiation. UVB causes thymine base pairs next to each other in genetic sequences to bond together into thymine dimers, a disruption in the strand that reproductive enzymes cannot copy. This leads to frameshifting during genetic replication and protein synthesis, usually killing the cell. Before formation of the UV-blocking ozone layer, when early prokaryotes approached the surface of the ocean, they almost invariably died out. The few that survived had developed enzymes that monitored the genetic material and removed thymine dimers by nucleotide excision repair enzymes. Many enzymes and proteins involved in modern mitosis and meiosis are similar to repair enzymes, and are believed to be evolved modifications of the enzymes originally used to overcome DNA damages caused by UV. Elevated levels of ultraviolet radiation, in particular UV-B, have also been speculated as a cause of mass extinctions in the fossil record. Photobiology Photobiology is the scientific study of the beneficial and harmful interactions of non-ionizing radiation in living organisms, conventionally demarcated around 10 eV, the first ionization energy of oxygen. UV ranges roughly from 3 to 30 eV in energy. Hence photobiology entertains some, but not all, of the UV spectrum. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Kythera] | [TOKENS: 4062] |
Contents Kythira Kythira (/kɪˈθɪərə, ˈkɪθɪrə/ kih-THEER-ə, KITH-irr-ə; Greek: Κύθηρα [ˈciθira]), also transliterated as Cythera, Kythera and Kithira,[a] is an island in Greece lying opposite the south-eastern tip of the Peloponnese peninsula. It is traditionally listed as one of the seven main Ionian Islands, although it is distant from the main group. Administratively, it belongs to the Islands regional unit, which is part of the Attica region, despite its distance from the Saronic Islands, around which the rest of Attica is centered. As a municipality, it includes the island of Antikythera to the south. The island is strategically located between the Greek mainland and Crete, and from ancient times until the mid-19th century was a crossroads of merchants, sailors, and conquerors. As such, it has had a long and varied history and has been influenced by many civilizations and cultures. This is reflected in its architecture (a blend of traditional, Aegean and Venetian elements), as well as the traditions and customs, influenced by centuries of coexistence of the Greek, and Venetian cultures. Administration Kythira and the nearby island of Antikythira were separate municipalities until they were merged at the 2011 local government reform; the two islands are now municipal units of Kythira municipality. The municipality has an area of 300.023 km2, the municipal unit 279.593 km2. The province of Kythira (Greek: Επαρχία Κυθήρων) was one of the provinces of Lakonia, then of Argolis and Korinthia, then of Attica Prefecture from 1929 to 1964. Then from 1964 to 1972 Kythira became part of the newly establishment Piraeus Prefecture and after dissolution of Piraeus prefecture returned to Attica Prefecture as part of Piraeus prefecture (Νομαρχία). It was abolished in 2006. From 2011 it is part of the Islands regional unit of Attica region. History There are archaeological remains from the Helladic period, contemporary with the Minoans. There is archaeological evidence of Kythiran trade as far as Egypt and Mesopotamia. Kythira had a Phoenician colony in the early archaic age; the sea-snail which produces Tyrian purple is native to the island.[citation needed] Xenophon refers to a Phoenician Bay in Kythira (Hellenica 4.8.7, probably Avlemonas Bay on the eastern side of the island). The archaic Greek city of Kythira was at Scandea on Avlemonas; its ruins have been excavated. Its acropolis, now Palicastro (Palaeocastron, "Old Fort"), has the temple of Aphrodite Ourania, who may well represent a Phoenician cult of Astarte. In classical times, Kythira was part of the territory of several larger city-states. Sparta took the island from Argos early in the sixth century BC, and ruled it under a kytherodíkes (kυθηροδίκης, "judge on Kythira"), in Thucydides' time [4,53,3]; Athens occupied it three times when at war with Sparta (in 456 BC during her first war with Sparta and the Peloponnesians; from 424 to 410 BC, through most of the great Peloponnesian War; and from 393 to 387/386BC, during the Corinthian War against Spartan dominance) and used it both to support her trade and to raid Laconia. Kythira was independent, and issued her own coins in 195 BC after the Achaean defeat of Sparta. In Augustus' time, it was again subject to Sparta, being the property of Gaius Julius Eurycles, who was both a Spartan magnate and a Roman citizen. By this time, the Greek cities were in practice subject to the Roman Empire. Kythira continued to exist under the Roman Empire and its Byzantine successor state for centuries. Christianity is attested from the fourth century AD, the time of Constantine; according to her legend, Saint Elessa came from Laconia to convert the island. Kythira is not mentioned in the literary sources for centuries after its conversion; in the period of Byzantine weakness at the end of the seventh century, it might have been exposed to attacks from both the Slavic tribes who raided the mainland and from Arab pirates from the sea. Archaeological evidence suggests the island was abandoned about 700 AD. When Saint Theodore of Cythera led a resettlement after the Byzantine reconquest of Crete in 962, he found the island occupied only by wandering bands of hunters. He established a great monastery at Paliochora; a town grew up around it, largely populated from Laconia. When the Byzantine Empire was divided among the conquerors of the Fourth Crusade, the Republic of Venice took her share, three eighths of the whole, as the Greek islands, Kythira among them. She established a coast patrol on Kythira and Antikythera to protect her trade route to Constantinople; Kythira was one of the islands Venice continued to hold despite the Greek reconquest of Constantinople and the Turkish presence all over the Near East. During the Venetian domination the island was known as Cerigo. Kythirans still talk about the destruction and looting of Paliochora by Barbarossa; it has become an intrinsic part of the Kytherian folklore. One can easily accept the stories of locals by noticing the number of monasteries embedded in the rocky hillsides to avoid destruction by the pirates. Barbary pirates ranged across the Mediterranean waters, raiding ships, coasts and islands, taking booty and slaves for the Barbary slave trade. Kythira was at the mercy of Barbary pirates due to its strategic location in the Mediterranean. In order to intercept merchant vessels, islands along the trade routes were of course more interesting for pirates. In the 17th century the small islands like Sapientza (Kalamatas) south of Messinia (district in south-western part of the Peloponnese), Cerigo (Kythira) south of the south-eastern tip of the Peloponnese, and along the coast of Asia minor, the then deserted islands of Fourni southwest of Samos, and the island of Psara, west of Chios, were all pirate bases. When Napoleon put an end to the Venetian Republic in 1797, Kythira was among the islands incorporated in that most distant department of France, called Mer-Égée. Kythira shared a common destiny with the other Ionian islands during the turbulent Napoleonic era, and is still regarded as one of them; it was counted as one of the Cyclades in antiquity. In 1799, the Ionian islands became the Septinsular Republic, nominally under Ottoman suzerainty, but in practice dominated by Imperial Russia. In 1807, the French recaptured the islands, before they were captured again by the British in 1809, who set up the United States of the Ionian Islands, a British protectorate. The British ruled over the islands for nearly half a century; under British rule, they were governed by a High Commissioner who was granted both legislative and executive powers. During the period of British rule, the city was known as Carigo or Cerigo, a name it had been acquired under Venetian control. After a long period of turbulence in the colony, which even eminent Commissioners as William Ewart Gladstone who served in the role for three weeks in the winter of 1859 failed to resolve, the British discussion whether they were a waste of money or a vital overseas possession ended with the cession of the Ionian Islands, including Kythira, to the new King George I of Greece, who was brother-in-law to the Prince of Wales. The chief town of the island, Kythira (or Chora, "village"), houses the Historical Archives of Kythira, the second largest in the Ionian islands, after Corfu. Geography Kythira has a land area of 279.593 square kilometres (107.95 sq mi); it is located at the southwestern exit from the Aegean Sea, behind Cape Malea. The rugged terrain is a result of prevailing winds from the surrounding seas which have shaped its shores into steep rocky cliffs with deep bays. The island has many beaches, of various composition and size; only half of them can be reached by road through the mountainous terrain of the island. The Kythirian Straits are nearby. Kythira is close to the Hellenic arc plate boundary zone, and thus highly prone to earthquakes. Many earthquakes in recorded history have had their epicentres near or on the island. Probably the largest in recent times is the 1903 earthquake near at the village of Mitata, that caused significant damage as well as limited loss of life. It has had two major earthquakes in the 21st century: that of November 5, 2004, measuring between 5.6 and 5.8 on the Richter scale and the earthquake of January 8, 2006, measuring 6.9 on the Richter scale. The epicenter of the latter was in the sea about 20 km (12 mi) to the east of Kythira, with a focus at a depth of approximately 70 km (43 mi). Many buildings were damaged, particularly old ones, mostly in the village of Mitata, but with no loss of life. It was felt as far as Italy, Egypt, Malta and Jordan. The municipal unit Kythira is subdivided into 13 communities (constituent settlements in parentheses): Kythira has a hot-summer Mediterranean climate (Köppen climate classification: Csa) with mild, rainy winters and warm to hot dry summers. Mythology In Ancient Greek mythology, Kythira was considered to be the island of celestial Aphrodite, the Goddess of love (cf. Cyprus, another island devoted to the Goddess of Love). Aphrodite is said to have been birthed from sea foam rising from the severed genitals of Uranus near the island. Cytherean /sɪθəˈriːən/ is an adjective literally meaning of Cythera (Latin Cytherēa, from the Greek adjective Κυθέρεια Kythereia, from Κύθηρα Kythēra 'Cythera'). The word Cytherean was first applied to the goddess and later, due to word taboo, to the planet Venus that had been named after the goddess. When planetary scientists began to have a need to discuss details of the planets, a need arose for generally accepted adjectives. As the planets had traditionally been associated with gods in classical mythology, there were commonly used adjectives that already related to some characteristic of the gods; for example, Mars and "martial" (warlike), Saturn and "saturnine" (gloomy). A consensus arose to use a slightly modified form - "Martian" for Mars, "Saturnian" for Saturn - that avoided these existing connotations. In the case of Venus, however, the traditional adjective would have been "Venereal" or "Venerial", which was strongly associated with sex (eg as in venereal disease), and the alternative term "Venerean"/"Venerian" (/vɪˈnɪəriən/) was felt by many astronomers to be too similar, and was generally avoided. The Greek name for Venus was Aphrodite; an adjective derived from that name would be "Aphrodisian" /æfroʊˈdɪziən/, or "Aphrodisial", which was again avoided due to a similarity to "aphrodisiac". A consensus arose to use "Cytherian" or "Cytherean"; Cytherēa had been used in Greek mythology as an alternative name for Aphrodite, derived from the legend that she had been born from the sea and emerged on the island of Cythera. The term "Venusian" /vɪˈnjuːʒ(i)ən/ was not originally popular as it was seen as clumsy; Sagan referred to it in 1966 as "a barbarism, comparable to 'Marsian', 'Jupiterian' or 'Earthian'.". However, practices shifted over the years, and in the 21st century "Venusian" is now the form most commonly used, with "Cytherean" less common.[citation needed] Demographics Like many of the smaller Aegean islands, Kythira's population is decreasing. While the island had reached a peak population of about 14,500 in 1864, that has steadily declined mostly due to emigration, both internal (to major urban centres of Greece) and external (to Australia, the United States, Germany) in the first half of the 20th century. Today its population hovers around 3,650 people (2021 census). Economy Since the late 20th century, the Kythirean economy has largely focused and, in the process, has become dependent on tourism, which provides the majority of the island's income, despite the fact that Kythira is not one of the most popular tourist destinations in Greece. The popular season usually begins with the Greek holiday of Pentecost at the end of May, and lasts until the middle of September. During this time, primarily during August, the island's population will often triple due to the tourists and natives returning for vacation. Dependence on tourism has resulted in increased building activity in many of the island's villages, mostly for commercial purposes (hotels and hospitality facilities, shops etc.), but also secondary homes; prominent examples are Agia Pelagia and Livadi, both of which having witnessed significant growth in their size since the early 1990s. Minor sources of revenue are thyme honey, famous within Greece for its rich flavor, as well as some small-scale cultivation of vegetables and fruit and animal husbandry that is, nevertheless, increasingly restricted to local consumption. Only five of the island's villages are on the coast (Platia Amos, Agia Pelagia, Diakofti, Avlemonas, & Kapsali). During July and August, several traditional dances will be held in various villages. These dances usually attract the majority of the island's population, the biggest of which are the festival of 'Panagia' in Potamos on 15 August, and the wine festival in Mitata on the first Friday and Saturday of August. Infrastructure The Trifylleion Hospital of Kythera is the only hospital on the island. The hospital's construction was made possible through the contributions of Greek Americans, including Mixalis Semitekolos, also known as Mike Semet, who was a prominent figure in the New York City restaurant industry in the early 20th century. Semitekolos, an immigrant from Kythera, raised funds for the hospital by participating in a pan-Kytherian fundraising campaign in the United States in the early 1950s. His significant monetary contributions earned him recognition from King Paul of Greece with the Order of the Phoenix. The groundbreaking for the hospital was on May 21, 1953, in Potamos, making it the first hospital on the island. It remains the only hospital on the island to this day, providing essential medical services to the residents of Kythira and the surrounding areas. The charitable organization responsible for the hospital evolved to become the Trifylleion Foundation of Kytherians and is still active today. Kythira (town) The capital, Chora, is located on the southern part of the island having no ports connected to the southern Peloponnese or Vatika. Kythira's port for Vatika was previously situated at Agia Pelagia, although in recent years this port has been decommissioned and has been replaced by a new port at the coastal town of Diakofti, Kythira. Most of the over 60 village names end with "-anika" and a few end with -athika, -iana and -wades. This is due to the villages being named after influential families that settled first in that region. For Example, 'Logothetianika' is derived from the Greek last name of 'Logothetis'. Officially, Greek is Kythira's main language. Despite popular belief, most places such as public services and local administrations, will be able to oblige to an individual's needs in English as well. In specific areas, some of Kythira's population is fluent in Italian. Transportation The island in the past has been plagued by a poor infrastructure, exacerbated by the effect of weather on transportation during the winter months.[citation needed] However the construction of the new port in Diakofti along with the renovation of the island's airport have significantly reduced these effects. A new road from the island's most populated town of Potamos in the north to the island's capital of Chora in the south is currently in the planning and development stage. Despite the fact that the island has been a trade route for centuries, construction of a modern port was postponed several times until the latter half of the 20th century. In 1933, efforts were made to construct a port in the village of Agia Pelagia, yet financial and governmental problems meant that it was only decades later that one was built. That small port of Agia Pelagia (currently being renovated from a ferry dock to a tourist/recreational boat dock) was the island's main port until the mid-1990s. Around that time the new port of Diakofti, the site originally chosen by the British colonial administration in the 19th century, was constructed along with a modern wider road, aiming to support larger cargo and passenger vessels. The port of Diakofti currently serves scheduled routes to/from Gythion, Kalamata, Antikythera, Piraeus' Athens port, Crete & Neapolis - Vatika. Proposals have been made to attach a marina to the south side of the port, however no plans or timetables have been produced. Additionally, the harbour of Agia Patrikia (north of Agia Pelagia) is the primary fishing boat harbour, housing two wide boatramps and a boat repair facility. The island's primary airport is the Alexander S. Onassis Airport also known as Kithira Island National Airport, located in the region between the village of Friligiannika and Diakofti, about 20 km (12 mi) from the capital. The airport was revamped and extended at the turn of the 21st century, largely by private funds provided by the local population. The island is served by Olympic Air and Aegean Airlines flights. Notable people In popular culture Gallery See also Notes References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Autotroph] | [TOKENS: 1803] |
Contents Autotroph An autotroph is an organism that can convert abiotic sources of energy into energy stored in organic compounds, which can be used by other organisms. Autotrophs produce complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide, generally using energy from light or inorganic chemical reactions. Autotrophs do not need a living source of carbon or energy and are the producers in a food chain, such as plants on land or algae in water. Autotrophs can reduce carbon dioxide to make organic compounds for biosynthesis and as stored chemical fuel. Most autotrophs use water as the reducing agent, but some can use other hydrogen compounds such as hydrogen sulfide. The primary producers can convert the energy in the light (phototroph and photoautotroph) or the energy in inorganic chemical compounds (chemotrophs or chemolithotrophs) to build organic molecules, which are usually accumulated in the form of biomass and will be used as carbon and energy source by other organisms (e.g. heterotrophs and mixotrophs). The photoautotrophs are the main primary producers, converting the energy of the light into chemical energy through photosynthesis, ultimately building organic molecules from carbon dioxide, an inorganic carbon source. Examples of chemolithotrophs are some archaea and bacteria (unicellular organisms) that produce biomass from the oxidation of inorganic chemical compounds; these organisms are called chemoautotrophs, and are frequently found in hydrothermal vents in the deep ocean. Primary producers are at the lowest trophic level, and are the reasons why Earth sustains life to this day. Autotrophs use a portion of the ATP produced during photosynthesis or the oxidation of chemical compounds to reduce NADP+ to NADPH to form organic compounds. Most chemoautotrophs are lithotrophs, using inorganic electron donors such as hydrogen sulfide, hydrogen gas, elemental sulfur, ammonium, and ferrous oxide as reducing agents; and hydrogen sources for biosynthesis and chemical energy release. Chemolithoautotrophs are microorganisms that synthesize energy through the oxidation of inorganic compounds. They can sustain themselves entirely on atmospheric CO2 and inorganic chemicals without the need for light or organic compounds. They enzymatically catalyze redox reactions using mineral substrates to generate ATP energy. These substrates primarily include hydrogen, iron, nitrogen, and sulfur. Its ecological niche is often specialized to extreme environments, including deep marine hydrothermal vents, stratified sediment, and acidic hot springs. History The term autotroph was coined by the German botanist Albert Bernhard Frank in 1892. It stems from the ancient Greek word τροφή (trophḗ), meaning "nourishment" or "food". The first autotrophic organisms likely evolved early in the Archean but proliferated across Earth's Great Oxidation Event with an increase to the rate of oxygenic photosynthesis by cyanobacteria. Photoautotrophs evolved from heterotrophic bacteria by developing photosynthesis. The earliest photosynthetic bacteria used hydrogen sulfide. Due to the scarcity of hydrogen sulfide, some photosynthetic bacteria evolved to use water in photosynthesis, leading to cyanobacteria. Variants Some organisms rely on organic compounds as a source of carbon, but are able to use light or inorganic compounds as a source of energy. Such organisms are mixotrophs. An organism that obtains carbon from organic compounds but obtains energy from light is called a photoheterotroph, while an organism that obtains carbon from organic compounds and energy from the oxidation of inorganic compounds is termed a chemolithoheterotroph. Evidence suggests that some fungi may also obtain energy from ionizing radiation: Such radiotrophic fungi were found growing inside a reactor of the Chernobyl nuclear power plant. Examples There are many different types of autotrophs in Earth's ecosystems. Lichens located in tundra climates are an exceptional example of a primary producer that, by mutualistic symbiosis, combines photosynthesis by algae (or additionally nitrogen fixation by cyanobacteria) with the protection of a decomposer fungus. As there are many examples of primary producers, two dominant types are coral and one of the many types of brown algae, kelp. Photosynthesis Gross primary production occurs by photosynthesis. This is the main way that primary producers get energy and make it available to other forms of life. Plants, many corals (by means of intracellular algae), some bacteria (cyanobacteria), and algae do this. During photosynthesis, primary producers receive energy from the sun and use it to produce sugar and oxygen. Ecology Without primary producers, organisms that are capable of producing energy on their own, the biological systems of Earth would be unable to sustain themselves. Plants, along with other primary producers, produce the energy that other living beings consume, and the oxygen that they breathe. It is thought that the first organisms on Earth were primary producers located on the ocean floor. Autotrophs are fundamental to the food chains of all ecosystems in the world. They take energy from the environment in the form of sunlight or inorganic chemicals and use it to create fuel molecules such as carbohydrates. This mechanism is called primary production. Other organisms, called heterotrophs, take in autotrophs as food to carry out functions necessary for their life. Thus, heterotrophs – all animals, almost all fungi, and most bacteria and protozoa – depend on autotrophs, or primary producers, for the raw materials and fuel they need. Heterotrophs obtain energy by breaking down carbohydrates or oxidizing organic molecules (carbohydrates, fats, and proteins) obtained in food. Carnivorous organisms rely on autotrophs indirectly, as the nutrients obtained from their heterotrophic prey come from autotrophs they have consumed. Most ecosystems are supported by the autotrophic primary production of plants and cyanobacteria that capture photons initially released by the sun. Plants can only use a fraction (approximately 1%) of this energy for photosynthesis. The process of photosynthesis splits a water molecule (H2O), releasing oxygen (O2) into the atmosphere, and reducing carbon dioxide (CO2) to release hydrogen atoms that fuel the metabolic process of primary production. Plants convert and store the energy of the photons into the chemical bonds of simple sugars during photosynthesis. These plant sugars are polymerized for storage as long-chain carbohydrates, such as starch and cellulose; glucose is also used to make fats and proteins. When autotrophs are eaten by heterotrophs, i.e., consumers such as animals, the carbohydrates, fats, and proteins contained in them become energy sources for the heterotrophs. Proteins can be made using nitrates, sulfates, and phosphates in the soil. Aquatic algae are a significant contributor to food webs in tropical rivers and streams. This is displayed by net primary production, a fundamental ecological process that reflects the amount of carbon that is synthesized within an ecosystem. This carbon ultimately becomes available to consumers. Net primary production displays that the rates of in-stream primary production in tropical regions are at least an order of magnitude greater than in similar temperate systems. Origin of autotrophs Researchers believe that the first cellular lifeforms were not heterotrophs as they would rely upon autotrophs since organic substrates delivered from space were either too heterogeneous to support microbial growth or too reduced to be fermented. Instead, they consider that the first cells were autotrophs. These autotrophs might have been thermophilic and anaerobic chemolithoautotrophs that lived at deep sea alkaline hydrothermal vents. This view is supported by phylogenetic evidence – the physiology and habitat of the last universal common ancestor (LUCA) is inferred to have also been a thermophilic anaerobe with a Wood-Ljungdahl pathway, its biochemistry was replete with FeS clusters and radical reaction mechanisms. It was dependent upon Fe, H2, and CO2. The high concentration of K+ present within the cytosol of most life forms suggests that early cellular life had Na+/H+ antiporters or possibly symporters. Autotrophs possibly evolved into heterotrophs when they were at low H2 partial pressures where the first form of heterotrophy were likely amino acid and clostridial type purine fermentations. It has been suggested that photosynthesis emerged in the presence of faint near-infrared light emitted by hydrothermal vents. The first photochemically active pigments are then thought to be Zn-tetrapyrroles. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Rabbinic_literature] | [TOKENS: 1087] |
Contents Rabbinic literature Rabbinic literature, in its broadest sense, is the entire corpus of works authored by rabbis throughout Jewish history. The term typically refers to literature from the Talmudic era (70–640 CE), as opposed to medieval and modern rabbinic writings. It aligns with the Hebrew term Sifrut Chazal (Hebrew: ספרות חז״ל), which translates to “literature [of our] sages” and generally pertains only to the sages (Chazal) from the Talmudic period. This more specific sense of "Rabbinic literature"—referring to the Talmud, Midrashim (Hebrew: מדרשים), and related writings, but hardly ever to later texts—is how the term is generally intended when used in contemporary academic writing. The terms mefareshim and parshanim (commentaries and commentators) almost always refer to later, post-Talmudic writers of rabbinic glosses on Biblical and Talmudic texts. Mishnaic literature The Midr'she halakha, Mishnah, and Tosefta (compiled from materials pre-dating the year 200 CE) are the earliest extant works of rabbinic literature, expounding and developing Judaism's Oral Law, as well as ethical teachings. Following these came the two Talmuds: The earliest extant material witness to rabbinic literature of any kind is the Tel Rehov inscription dating to the 6th–7th centuries, also the longest Jewish inscription from late antiquity. Meanwhile, the earliest extant Talmudic manuscripts are from the 8th century. The Midrash Midrash (מדרש; pl. Midrashim) is a Hebrew word referring to a method of reading details into or out of a biblical text. The term midrash also can refer to a compilation of Midrashic teachings in the form of legal, exegetical, homiletical, or narrative writing, often configured as a commentary on the Bible or Mishnah. There are a large number of "classical" Midrashic works spanning a period from Mishnaic to Geonic times, often showing evidence of having been worked and reworked from earlier materials and frequently coming to us in multiple variants. A compact list of these works, drawing upon Barry Holtz's Back to the Sources, is given below. The timeline below is approximate because many of the works were composed over a long period, borrowing and collating material from earlier versions; their histories are, therefore, somewhat uncertain and the subject of scholarly debate. In the table, "n.e." designates that the work in question is not extant except in secondary references. Tannaitic period (till 200 CE) Mekhilta of Rabbi Ishmael Mekhilta of Rabbi Shimon Mekilta le-Sefer Devarim (n.e.) Sifra Sifre Sifre Zutta Alphabet of Akiba ben Joseph (?) Seder Olam Rabbah 400–650 CE Genesis Rabbah Midrash Tanhuma Lamentations Rabbah Leviticus Rabbah 650–900 CE Midrash Proverbs Ecclesiastes Rabbah Deuteronomy Rabbah Pesikta de-Rav Kahana Pesikta Rabbati Avot of Rabbi Natan Pirkei de-Rabbi Eliezer Seder Olam Zutta Tanna Devei Eliyahu 900–1000 CE Midrash Psalms Exodus Rabbah Ruth Zuta Lamentations Zuta 1000–1200 Midrash Aggadah of Moses ha-Darshan Midrash Tadshe Later Yalkut Shimoni Midrash ha-Gadol Ein Yaakov Numbers Rabbah Later works by category Later works by historical period The Geonim are the rabbis of Sura and Pumbeditha in Babylon (650–1250 CE) : The Rishonim are the rabbis of the early medieval period (1000–1550 CE) The Acharonim are the rabbis from 1550 to the present day. Mefareshim Mefareshim is a Hebrew word meaning "commentators" (or roughly meaning "exegetes"), Perushim means "commentaries". In Judaism, these words refer to commentaries on the Torah (five books of Moses), Tanakh, Mishnah, Talmud, the responsa literature, or even the siddur (Jewish prayerbook), and more. Classic Torah and/or Talmud commentaries have been written by the following individuals: Classical Talmudic commentaries were written by Rashi. After Rashi, the Tosafot was written, which was an omnibus commentary on the Talmud by the disciples and descendants of Rashi; this commentary was based on discussions done in the rabbinic academies of Germany and France.[citation needed] Modern Torah commentaries which have received wide acclaim in the Jewish community include: Modern Siddur commentaries have been written by: See also References Bibliography External links |
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[SOURCE: https://en.wikipedia.org/wiki/Grey_alien#cite_note-Magonia-12] | [TOKENS: 2835] |
Contents Grey alien Grey aliens, also referred to as Zeta Reticulans, Roswell Greys, or simply, Greys,[a] are purported extraterrestrial beings. They are frequently featured in claims of close encounter and alien abduction. Greys are typically described as having small, humanoid bodies, smooth, grey skin, disproportionately large, hairless heads, and large, black, almond-shaped eyes. The 1961 Barney and Betty Hill abduction claim was key to the popularization of Grey aliens. Precursor figures have been described in science fiction and similar descriptions appeared in later accounts of the 1947 Roswell UFO incident and early accounts of the 1948 Aztec UFO hoax. The Grey alien is cited an archetypal image of an intelligent non-human creature and extraterrestrial life in general, as well as an iconic trope of popular culture in the age of space exploration. Description Greys are typically depicted as grey-skinned, diminutive humanoid beings that possess reduced forms of, or completely lack, external human body parts such as noses, ears, or sex organs. Their bodies are usually depicted as being elongated, having a small chest, and lacking in muscular definition and visible skeletal structure. Their legs are depicted as being shorter and jointed differently from humans with limbs proportionally different from a human. Greys are depicted as having unusually large heads in proportion to their bodies, and as having no hair, no noticeable outer ears or noses, and small orifices for ears, nostrils, and mouths. In drawings, Greys are almost always shown with very large, opaque, black eyes, without eye whites. They are frequently described as shorter than average adult humans. The association between Grey aliens and Zeta Reticuli originated with the interpretation of a map drawn by Betty Hill by a school-teacher named Marjorie Fish sometime in 1969. Betty Hill, under hypnosis, had claimed to have been shown a map that displayed the aliens' home system and nearby stars. Upon learning of this, Fish attempted to create a model from a drawing produced by Hill, eventually determining that the stars marked as the aliens' home were Zeta Reticuli, a binary star system. History In literature, descriptions of beings similar to Grey aliens predate claims of supposed encounters with them. In 1893, H. G. Wells presented a description of humanity's future appearance in the article "The Man of the Year Million", describing humans as having no mouths, noses, or hair, and with large heads. In 1895, Wells also depicted the Eloi, a successor species to humanity, in similar terms in the novel The Time Machine. Both share many characteristics with future perceptions of Greys. As early as 1917, the occultist Aleister Crowley described a meeting with a "preternatural entity" named Lam that was similar in appearance to a modern Grey. Crowley claimed to have contacted Lam through a process called the "Amalantrah Workings," which he believed allowed humans to contact beings from outer space and across dimensions. Other occultists and ufologists, many of whom have retroactively linked Lam to later Grey encounters, have since described their own visitations from him, with one describing the being as a "cold, computer-like intelligence," and utterly beyond human comprehension. ...the creatures did not resemble any race of humans. They were short, shorter than the average Japanese, and their heads were big and bald, with strong, square foreheads, and very small noses and mouths, and weak chins. What was most extraordinary about them were the eyes—large, dark, gleaming, with a sharp gaze. They wore clothes made of soft grey fabric, and their limbs seemed to be similar to those of humans. In 1933, the Swedish novelist Gustav Sandgren, using the pen name Gabriel Linde, published a science fiction novel called Den okända faran (The Unknown Danger), in which he describes a race of extraterrestrials who wore clothes made of soft grey fabric and were short, with big bald heads, and large, dark, gleaming eyes. The novel, aimed at young readers, included illustrations of the imagined aliens. This description would become the template upon which the popular image of grey aliens is based. The conception remained a niche one until 1965, when newspaper reports of the Betty and Barney Hill abduction made the archetype famous. The alleged abductees, Betty and Barney Hill, claimed that in 1961, humanoid alien beings with greyish skin had abducted them and taken them to a flying saucer. In his 1990 article "Entirely Unpredisposed", Martin Kottmeyer suggested that Barney's memories revealed under hypnosis might have been influenced by an episode of the science-fiction television show The Outer Limits titled "The Bellero Shield", which was broadcast 12 days before Barney's first hypnotic session. The episode featured an extraterrestrial with large eyes, who says, "In all the universes, in all the unities beyond the universes, all who have eyes have eyes that speak." The report from the regression featured a scenario that was in some respects similar to the television show. In part, Kottmeyer wrote: Wraparound eyes are an extreme rarity in science fiction films. I know of only one instance. They appeared on the alien of an episode of an old TV series The Outer Limits entitled "The Bellero Shield." A person familiar with Barney's sketch in "The Interrupted Journey" and the sketch done in collaboration with the artist David Baker will find a "frisson" of "déjà vu" creeping up his spine when seeing this episode. The resemblance is much abetted by an absence of ears, hair, and nose on both aliens. Could it be by chance? Consider this: Barney first described and drew the wraparound eyes during the hypnosis session dated 22 February 1964. "The Bellero Shield" was first broadcast on 10 February 1964. Only twelve days separate the two instances. If the identification is admitted, the commonness of wraparound eyes in the abduction literature falls to cultural forces. — Martin Kottmeyer, Entirely Unpredisposed: The Cultural Background of UFO Reports Carl Sagan echoed Kottmeyer's suspicions in his 1997 book, The Demon Haunted World: Science as a Candle in the Dark, where Invaders from Mars was cited as another potential inspiration. After the Hills' encounter, Greys would go on to become an integral part of ufology and other extraterrestrial-related folklore. This is particularly true in the case of the United States: according to journalist C. D. B. Bryan, 73% of all reported alien encounters in the United States describe Grey aliens, a significantly higher proportion than other countries.: 68 During the early 1980s, Greys were linked to the alleged crash-landing of a flying saucer in Roswell, New Mexico, in 1947. A number of publications contained statements from individuals who claimed to have seen the U.S. military handling a number of unusually proportioned, bald, child-sized beings. These individuals claimed, during and after the incident, that the beings had oversized heads and slanted eyes, but scant other distinguishable facial features. In 1987, novelist Whitley Strieber published the book Communion, which, unlike his previous works, was categorized as non-fiction, and in which he describes a number of close encounters he alleges to have experienced with Greys and other extraterrestrial beings. The book became a New York Times bestseller, and New Line Cinema released a 1989 film adaption that starred Christopher Walken as Strieber. In 1988, Christophe Dechavanne interviewed the French science-fiction writer and ufologist Jimmy Guieu on TF1's Ciel, mon mardi !. Besides mentioning Majestic 12, Guieu described the existence of what he called "the little greys", which later on became better known in French under the name: les Petits-Gris. Guieu later wrote two docudramas, using as a plot the Grey aliens / Majestic-12 conspiracy theory as described by John Lear and Milton William Cooper: the series "E.B.E." (for "Extraterrestrial Biological Entity"): E.B.E.: Alerte rouge (first part) (1990) and E.B.E.: L'entité noire d'Andamooka (second part) (1991).[citation needed] Greys have since become the subject of many conspiracy theories. Many conspiracy theorists believe that Greys represent part of a government-led disinformation or plausible deniability campaign, or that they are a product of government mind-control experiments. During the 1990s, popular culture also began to increasingly link Greys to a number of military-industrial complex and New World Order conspiracy theories. In 1995, filmmaker Ray Santilli claimed to have obtained 22 reels of 16 mm film that depicted the autopsy of a "real" Grey supposedly recovered from the site of the 1947 incident in Roswell. In 2006, though, Santilli announced that the film was not original, but was instead a "reconstruction" created after the original film was found to have degraded. He maintained that a real Grey had been found and autopsied on camera in 1947, and that the footage released to the public contained a percentage of that original footage. Analysis Greys are often involved in alien abduction claims. Among reports of alien encounters, Greys make up about 50% in Australia, 73% in the United States, 48% in continental Europe, and around 12% in the United Kingdom.: 68 These reports include two distinct groups of Greys that differ in height.: 74 Abduction claims are often described as extremely traumatic, similar to an abduction by humans or even a sexual assault in the level of trauma and distress. The emotional impact of perceived abductions can be as great as that of combat, sexual abuse, and other traumatic events. The eyes are often a focus of abduction claims, which often describe a Grey staring into the eyes of an abductee when conducting mental procedures. This staring is claimed to induce hallucinogenic states or directly provoke different emotions. Neurologist Steven Novella proposes that Grey aliens are a byproduct of the human imagination, with the Greys' most distinctive features representing everything that modern humans traditionally link with intelligence. "The aliens, however, do not just appear as humans, they appear like humans with those traits we psychologically associate with intelligence." In 2005, Frederick V. Malmstrom, writing in Skeptic magazine, Volume 11, issue 4, presents his idea that Greys are actually residual memories of early childhood development. Malmstrom reconstructs the face of a Grey through transformation of a mother's face based on our best understanding of early-childhood sensation and perception. Malmstrom's study offers another alternative to the existence of Greys, the intense instinctive response many people experience when presented an image of a Grey, and the act of regression hypnosis and recovered-memory therapy in "recovering" memories of alien abduction experiences, along with their common themes. According to biologist Jack Cohen, the typical image of a Grey, assuming that it would have evolved from a world with different environmental and ecological conditions from Earth, is too physiologically similar to a human to be credible as a representation of an alien. The interdimensional hypothesis, the cryptoterrestrial hypothesis, and the time-traveller hypothesis attempt to provide an alternative explanation to the humanoid anatomy and behavior of these alleged beings. In popular culture Depictions of Grey aliens have gone on to appear in a number of films and television shows, supplanting the previously popular little green men. As early as 1966, for example, the superhero character Ultraman was explicitly based on them, and in 1977 they were featured in Close Encounters of the Third Kind. Greys have also been worked into space opera and other interstellar settings: in Babylon 5, the Greys are referred to as the "Vree", and are depicted as being allies and trade partners of 23rd-century Earth, while in the Stargate franchise they are called the "Asgard" and depicted as ancient astronauts allied with modern-day Earth.[citation needed] South Park refers to them as "visitors". During the 1990s, plotlines wherein Greys were linked to conspiracy theories became common. A well-known example is the Fox television series The X-Files, which first aired in 1993. It combined the quest to find proof of the existence of Grey-like extraterrestrials with a number of UFO conspiracy theory subplots, to form its primary story arc. Other notable examples include the XCOM video game franchise (where they are called "Sectoids"); Dark Skies, first broadcast in 1996, which expanded upon the MJ-12 conspiracy;[citation needed] and American Dad!, which features a Grey-like alien named Roger, whose backstory draws from both the Roswell incident and Area 51 conspiracy theories. The 2011 film Paul tells the story of a Grey named Paul who attributes the Greys' frequent presence in science fiction pop culture to the US government deliberately inserting the stereotypical Grey alien image into mainstream media; this is done so that if humanity came into contact with Paul's species, no immediate shock would occur as to their appearance. Child abduction by Greys is a key plot point in the 2013 film, Dark Skies. Greys appear in Syfy's 2021 science fiction dramedy series Resident Alien. The Greys appear as the main antagonistic faction in the 2023 independent game Greyhill Incident. See also Notes References External links |
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[SOURCE: https://he.wikipedia.org/wiki/אנציקלופדיה_בריטניקה] | [TOKENS: 28680] |
תוכן עניינים אנציקלופדיה בריטניקה אנציקלופדיה בריטניקה (מלטינית: Encyclopædia Britannica) היא אנציקלופדיה שמוציאה לאור חברה באותו שם מאז שנת 1768. בריטניקה היא הוותיקה מבין האנציקלופדיות באנגלית שעודן מוסיפות להתעדכן. ב-14 במרץ 2012 הודיע המו"ל על הפסקת הפקתן של מהדורות דפוס חדשות, והתמקדות בגרסה המקוונת של האנציקלופדיה. מהדורות המהדורה הראשונה של הבריטניקה יצאה לאור בשנים 1768 עד 1771 באדינבורו שבסקוטלנד, בשלושה כרכים. עד מהרה צמח מניין הכרכים, ובמהדורתה השלישית, משנת 1801, עמד על 20. יוקרתה העולה של האנציקלופדיה בריטניקה סייעה לגיוס כותבים בעלי-שם, ומהדורותיה התשיעית (1875-1889) והאחת-עשרה (1911) מוחזקות כציוני-דרך בתולדות האנציקלופדיות, זאת בשל עומקן וסגנון הכתיבה הרהוט שהתאפיינו בו. מאז צאת המהדורה האחת-עשרה לאור, נתקצרו ערכי האנציקלופדיה בריטניקה ופושטו בהליך הדרגתי, על מנת להופכם לנגישים יותר לציבור הרחב. בשנת 1933 הייתה בריטניקה לאנציקלופדיה הראשונה שאימצו מדיניות "עדכון מתמיד", לפיה האנציקלופדיה מודפסת שוב ושוב לאורך השנים, כאשר הערכים מתעדכנים תדיר בהתאם ללוח זמנים קבוע. המהדורה האחרונה שיצאה לאור (נכון ל-2008), המהדורה החמש-עשרה, מורכבת ממבנה ייחודי בן שלושה חלקים: מיקרופדיה בת שנים-עשר כרכים ובהם ערכים קצרים (לרוב מספר המילים בהם אינו עולה על 750), מאקרופדיה בת שבעה-עשר כרכים בעלי ערכים ארוכים (המתפרשים על פני שניים עד 310 עמודים) וכרך פרופדיה, שמיועד להציג מבנה היררכי של כל הידע האנושי, ברוח חזונו של מורטימר ג'. אדלר (יושב-הראש של מועצת העורכים בעבר). המיקרופדיה נועדה לשמש לבדיקת עובדות מהירה וכמדריך למאקרופדיה; הקוראים מונחים ללמוד את תרשים כל הידע האנושי המצוי בפרופדיה כדי לתפוס את ההקשר הכללי שבו מצוי נושא מסוים, וכן על-מנת למצוא ערכים מפורטים אחרים בנושאים סמוכים. ערכי המהדורה החמש עשרה של האנציקלופדיה נכתבו על ידי צוות המונה 19 עורכים במשרה מלאה ולמעלה מ-4,000 כותבים מקצועיים. גודלה של האנציקלופדיה בריטניקה נותר קבוע למדי במשך שבעים השנים האחרונות של המאה העשרים, ועמד על כ-40 מיליון מילים. הגם שמלאכת ההוצאה לאור חצתה את האוקיינוס האטלנטי ומצאה את משכנה הקבוע בארצות הברית למן שנת 1901, מוסיפה האנציקלופדיה להיכתב על פי כללי האיות הבריטיים. במרוצת שנותיה, התקשו המו"לים של האנציקלופדיה בריטניקה לשמור על רווחיות - אתגר שעמו מתמודדים מוציאים לאור של אנציקלופדיות רבות. האנציקלופדיה בריטניקה החליפה ידיים פעמים מספר, ועם בעליה בעבר נמנים המוציא לאור הסקוטי A & C Black, הוראס אוורט הופר, חברת סירס רובק וויליאם בנטון. הבעלים הנוכחים של האנציקלופדיה בריטניקה הוא יעקב (ז'אקי) ספרא, מיליארדר יהודי-שווייצרי. התפתחויות מהשנים האחרונות בטכנולוגיית המידע, ועלייתן של אנציקלופדיות אלקטרוניות דוגמת אנכרטא וויקיפדיה, הפחיתו את הביקוש לאנציקלופדיות מודפסות. על מנת לשמור על תחרותיות, חברת אנציקלופדיה בריטניקה שמה דגש על המוניטין הטוב של האנציקלופדיה בריטניקה, הפחיתה את המחיר ואת עלויות ההוצאה לאור, ופיתחה גרסאות אלקטרוניות הזמינות על גבי אמצעים שונים, ובהם CD-ROM ו-DVD, ובאינטרנט. היסטוריה האנציקלופדיה בריטניקה יצאה במהלך השנים בחמש-עשרה מהדורות רשמיות, בנוסף לנספחים מרובי-כרכים למהדורות השלישית והחמישית. במובן המצומצם, המהדורה העשירית לא הייתה אלא נספח למהדורה התשיעית, כשם שהמהדורות השתים-עשרה והשלוש-עשרה היו נספחים למהדורה האחת-עשרה. המהדורה החמש-עשרה, שיצאה לאור לראשונה בשנת 1974, עברה ארגון-מחדש בשנת 1985, אך המהדורה הנוכחית, הנמכרת בחנויות בשנות האלפיים, עודנה ידועה בתור המהדורה החמש-עשרה של האנציקלופדיה בריטניקה. לאורך ההיסטוריה שלה, האנציקלופדיה בריטניקה חתרה להגשים שתי מטרות: להיות ספר-יעץ ולהוות חומר לימוד בעבור אלו המעוניינים להרחיב את השכלתם. בשנת 1974 אומצה לגבי המהדורה החמש-עשרה מטרה נוספת: לסדר בשיטתיות את כל הידע האנושי. ניתן לחלק את ההיסטוריה של האנציקלופדיה בריטניקה לחמש תקופות עיקריות, בחלוקה לפי שינויים מרכזיים בניהול הפקת האנציקלופדיה ובצורת ארגונה. בתקופה הראשונה (המהדורות הראשונה עד השישית, 1768-1826), נוהלה הוצאת האנציקלופדיה בריטניקה על ידי מייסדיה, קולין מקפרקוואר ואנדרו בל, וכן על ידי חבריהם וקרובי משפחתם, דוגמת תומאס בונאר, ג'ורג' גלייג וארצ'יבלד קונסטבל. האנציקלופדיה יצאה לאור במהדורתה הראשונה בין השנים 1768 ל-1771 באדינבורו, בשם Encyclopædia Britannica או A dictionary of arts and sciences, compiled upon a new plan (מילון לאמנויות והמדעים, חובר על-פי תוכנית חדשה). היא נתפסה כתגובה שמרנית לאנציקלופדיה הגדולה של דני דידרו, שיצאה לאור בין השנים 1751 ל-1766. האנציקלופדיה בריטניקה הייתה בעיקר מיזם סקוטי, כמשתקף בסמלה. יסוד האנציקלופדיה בריטניקה הוא אחד מהנודעים ובני-הקיימא שבפירות מורשת תקופת הנאורות הסקוטית. בתקופה זו, האנציקלופדיה בריטניקה הפכה ממהדורה ראשונה צנועה, בת שלושה כרכים שחוברו על ידי עורך צעיר אחד, עד למהדורה השישית בת 20 הכרכים שנכתבו בידי בני-סמכא רבים. הגם שמספר אנציקלופדיות אחרות התחרו באנציקלופדיה בריטניקה, כגון הציקלופדיה של ריס והאנציקלופדיה מטרופוליטנה של קולרידג', עד מהרה פשטו מתחרים אלה את הרגל או נטשו את המיזם בלתי-גמור בשל מחלוקות בין עורכיהם. עד תום תקופה זה, הייתה לאנציקלופדיה בריטניקה רשת ענפה של כותבים בעלי-שם, בעיקר הודות להיכרויות אישיות שלהם עם העורכים, במיוחד קונסטבל וגלייג. במהלך התקופה השנייה (המהדורות השביעית עד התשיעית, 1827-1901), נוהלה האנציקלופדיה בריטניקה על ידי בית ההוצאה לאור A & C Black. הגם שמספר כותבים גויסו הודות לידידות אישית עם העורכים הראשיים, ובמיוחד מקווי נייפייר, רבים אחרים נמשכו בזכות המוניטין המצוינים של האנציקלופדיה. מוצאם של רבים מהתורמים לא היה בריטי ולעיתים הם נמנו עם ברי-הסמכא המוכרים ביותר בתחום התמחותם. מפתח עניינים כללי לכל הערכים נכלל לראשונה במהדורה השביעית, מנהג שנשמר עד שמורטימר ג'. אדלר, יו"ר מועצת העורכים של האנציקלופדיה בריטניקה, החליט לוותר עליו לקראת הוצאתה לאור של המהדורה החמש-עשרה בשנת 1974. העורך הראשי הראשון שלא היה סקוטי, אלא אנגלי, היה תומאס ספנסר ביינס, שניהל את הפקת המהדורה התשיעית הנודעת של האנציקלופדיה בריטניקה; מהדורה זו זכתה לכינוי "מהדורת המלומדים". על פי רוב, היא אמנם נחשבת לבעלת הרמה האקדמית הגבוהה ביותר מבין כלל מהדורות הבריטניקה עד כה. בפרוס המאה העשרים הייתה המהדורה התשיעית כבר מיושנת למדי, והאנציקלופדיה בריטניקה עמדה בפני קשיים כלכליים ניכרים. במהלך התקופה השלישית (המהדורות העשירית עד הארבע-עשרה, 1901-1973), האנציקלופדיה בריטניקה נוהלה על ידי אנשי-עסקים אמריקאיים, שעשו שימוש בשיטות שיווק אגרסיביות חדשות דוגמת שיווק ישיר ושיווק מדלת לדלת כדי להגדיל את רווחיהם. הבעלים האמריקאיים אף הובילו בהדרגה תהליך של פישוט תוכני באנציקלופדיה, ובכך הפכו את ערכיה לאקדמיים פחות אך נגישים יותר לקורא הממוצע. המהדורה העשירית לא הייתה אלא נספח למהדורה התשיעית שהופק בחופזה, אך את המהדורה האחת-עשרה משבחים על שום מצוינותה עד עצם היום הזה; הבעלים, הוראס אוורט הופר, לא חסך במאמצים על מנת להביאה לידי שלמות. כאשר הופר נקלע לקשיים כלכליים, עבר ניהול האנציקלופדיה בריטניקה לידי תאגיד סירס רובק למשך שמונה-עשרה שנים בקירוב (1920-1923, 1928-1943). בשנת 1932, סגן נשיא חברת סירס, אלקן הריסון פאואל, נטל לידיו את נשיאות הבריטניקה; בשנת 1936, הוא הנהיג את מדיניות העדכון המתמיד (שלא הופסקה מאז), לפיה כל ערך נבדק ומעודכן במידת הצורך פעמיים בעשור. היה זה שינוי גדול בהשוואה לנוהג הקודם, לפיו הערכים לא שונו כלל עד להפקת המהדורה הבאה, לאחר כ-25 שנה בממוצע, כאשר לעיתים היו אף ערכים שעברו בלא כל שינוי למהדורה החדשה. פאואל השקיע בפיתוח מוצרים חינוכיים שעשו שימוש במוניטין של הבריטניקה. בשנת 1943 עברה הבעלות על האנציקלופדיה בריטניקה מתאגיד סירס רובק לוויליאם בנטון, שניהל אותה עד יומו האחרון, בשנת 1973. בנטון אף יסד את קרן בנטון, שניהלה את הבריטניקה עד לשנת 1996. בשנת 1968 נערכו חגיגות ה-200 לצאת המהדורה הראשונה של האנציקלופדיה. בתקופה הרביעית (המהדורה החמש-עשרה של האנציקלופדיה בריטניקה, 1974-1994), הושקה המהדורה החמש-עשרה של הבריטניקה, והאנציקלופדיה פוצלה לשלושה חלקים: מיקרופדיה, מאקרופדיה ופרופדיה. תחת השפעתו הרבה של מורטימר ג'. אדלר (חבר מועצת העורכים של האנציקלופדיה בריטניקה מאז הקמתה בשנת 1949, ויושב-ראש שלה משנת 1974; מנהל תוכנית העורכים בעבור המהדורה החמש-עשרה למן שנת 1965), האנציקלופדיה בריטניקה שאפה לא רק להוות ספר-יעץ מובחר ואמצעי חינוכי חשוב, אלא אף לסדר ולארגן את כל הידע האנושי מאז ומעולם. היעדרו של מפתח-עניינים נפרד וקיבוצם של הערכים לשתי אנציקלופדיות מקבילות (המיקרופדיה והמאקרופדיה) הביאו לביקורות רבות על המהדורה החמש-עשרה בראשית דרכה. בתגובה לכך, המהדורה החמש-עשרה עברה ארגון-מחדש נוסף ויצאה בהשקה מחודשת בשנת 1985, עם שני כרכי מפתח עניינים חדשים. גרסה שנייה זו למהדורה החמש-עשרה ממשיכה להיות מודפסת עד היום, בכפוף למדיניות העדכון המתמיד; הגרסה האחרונה היא גרסת הדפוס של שנת 2007. שמה הרשמי של המהדורה החמש-עשרה הוא New Encyclopædia Britannica (האנציקלופדיה בריטניקה החדשה), הגם שלשם קידום המכירות נעשה שימוש אף בשם "Britannica 3". בתקופה החמישית (1994 ואילך), פותחו גרסאות ממוחשבות של האנציקלופדיה בריטניקה והגיעו למדפים מעל גבי אמצעי אחסון אופטיים (כגון CD-ROM). בשנת 1996 נרכשה האנציקלופדיה בריטניקה על ידי יעקב (ז'אקי) ספרא, איל-הון שווייצרי, במחיר נמוך בהרבה ממחיר השוק המוערך של החברה, וזאת בשל קשייה הכלכליים. חברת אנציקלופדיה בריטניקה פוצלה לשניים בשנת 1999. חלק אחד שמר על שמה של החברה והמשיך לשקוד על פיתוח המהדורה המודפסת, ואילו החלק האחר, חברת בריטניקה.קום (Britannica.com Inc), נטל את האחריות על הגרסאות הממוחשבות השונות. למן שנת 2001 ועד לשנת 2006, חלקו שתי החברות מנכ"ל משותף - הישראלי אילן ישועה, שהמשיך באסטרטגיה של פאואל שתמכה בצמיחה מרבית של חברת האנציקלופדיה בריטניקה על ידי ניצול מרבי של מוניטין האנציקלופדיה ומותגה לשיווק מוצרי-משנה. כיום החל משנת 1985, האנציקלופדיה בריטניקה נחלקת לארבעה חלקים: מיקרופדיה, מאקרופדיה, פרופדיה ומפתח עניינים בן שני כרכים. ערכי הבריטניקה נמצאים בחלקי המיקרופדיה והמאקרופדיה, הכוללים שנים-עשר ושבעה-עשר כרכים בהתאמה, כל כרך מונה כאלף עמודים בקירוב. המאקרופדיה של שנת 2007 כוללת 699 ערכי עומק, שאורכם נע משניים ל-310 עמודים, וכל אחד מהם חתום על ידי כותבו וכולל רשימת מקורות. לעומת זאת, המיקרופדיה לשנת 2007 מונה כ-65,000 ערכים, רובם המוחלט (כ-97%) אינם עוברים באורכם את רף 750 המילים, ואינם כוללים רשימת מקורות או את שם הכותב. ערכי המיקרופדיה נועדו לבדיקת עובדות מהירה ולעזרה במציאת מידע נוסף במאקרופדיה. ערכי המאקרופדיה נועדו לשמש הן כמאמרים איכותיים פרי עטם של כותבים בני-סמכא בתחומם, והם כמאגרים של מידע שאין למוצאו בכל מקום אחר. הערך הארוך ביותר (310 עמודים אורכן) הוא על ארצות הברית, והוא מהווה תוצר של מיזוג כל ערכי המדינות השונות בארצות הברית לתוכו. ניתן להגיע לפריט מידע מסוים באנציקלופדיה בריטניקה על פי ההפניות הכפולות בין המיקרופדיה למאקרופדיה; אולם, הן נדירות למדי, אחת לעמוד בממוצע. מכאן, הקוראים מונחים להיעזר במפתח העניינים האלפביתי או בפרופדיה, המארגנת את תוכני הבריטניקה על פי תחומים. עיקר הפרופדיה הוא "תרשים כל הידע האנושי", השואף להוות מסגרת לוגית לכל הידע האנושי. לפיכך, עורכי האנציקלופדיה בריטניקה נעזרים בתרשים על מנת להכריע בשאלת הכנסת ערכים חדשים למיקרופדיה ולמאקרופדיה. התרשים יועד אף להוות מדריך ללומדים, לשים נושאים בפרספקטיבה היאה להם, ולהציע סדרת ערכים בבריטניקה לתלמיד המעוניין ללמוד נושא לעומקו. אולם, על פי נתוני הספריות לא נעשה בפרופדיה כמעט שימוש, והמבקרים המליצו לבטל כליל כרך זה. הפרופדיה כוללת גם אטלס אנטומי קטן וכן מספר נספחים המונים את חברי צוות הבריטניקה, היועצים והתורמים לכל שלושת החלקים. בהתייחס אליהן כאל יחידה אחת, המיקרופדיה והמאקרופדיה כוללות בערך 40 מיליון מילים ו-24,000 איורים. שני כרכי מפתח העניינים כוללים 2,350 עמודים, ומפורטים בהם 228,274 נושאים המכוסים על ידי האנציקלופדיה, בנוסף ל-474,675 תת-נושאים תחתם. הבריטניקה עושה על פי רוב שימוש בשיטת האיות הבריטית ולא האמריקאית; כך לדוגמה, נכתב colour (ולא color), וכן centre (ולא center) ו-encyclopædia (ולא encyclopedia). אולם, לכלל זה ישנם חריגים, דוגמת defense במקום defence. איותים חלופיים נפוצים זוכים להפניה דוגמת "Color: see Colour". למן שנת 1936, ערכי האנציקלופדיה בריטניקה מעודכנים על בסיס קבוע, כאשר לפחות 10 אחוזים מהם נשקלים כמועמדים לעדכון בכל שנה. על פי אחד מאתרי הבריטניקה, 46% מהערכים עודכנו במהלך שלוש השנים האחרונות; אולם, על פי אתר אחר של הבריטניקה, רק 35% מהערכים עודכנו בתקופה זו. הסידור האלפביתי של הערכים במיקרופדיה ובמאקרופדיה נעשה על פי כללים נוקשים. סימנים דיאקריטיים ואותיות לא-אנגליות זוכים להתעלמות, בעוד שערכים מספריים, דוגמת "1812, War of" מסודרים אלפביתית כאילו המספר נכתב במילים ("Eighteen-twelve, War of"). ערכים עם שמות זהים מסודרים תחילה על פי אישים, אחר כך אתרים ולבסוף עצמים. שליטים בעלי שמות זהים מסודרים תחילה על פי סדר אלפביתי של מדינותיהם ואחר כך כרונולוגית; כך, שארל השלישי מצרפת קודם לצ'ארלס הראשון מבריטניה. בדומה לכך, אתרים החולקים שמות זהים מסודרים אלפביתית על פי מדינה ואחר כך על פי חלוקה מנהלית הולכת וקטנה. תקליטור ה-DVD שנקרא Britannica Ultimate Reference Suite 2006 כולל למעלה מ-55 מיליון מילים ולמעלה מ-100,000 ערכים. הוא כולל 73,645 ערכים רגילים מן הבריטניקה, והיתר שאולים מן ה-Britannica Student Encyclopædia, the Britannica Elementary Encyclopædia וה-Britannica Book of the Year (1993–2004), ובנוסף עוד מספר ערכים "קלאסיים" ממהדורות ישנות יותר של האנציקלופדיה. חבילה זו כוללת מגוון תכנים נספחים ובהם מפות, סרטוני וידאו, קטעי קול, סרטוני הנפשה וקישורים לרשת האינטרנט. היא אף מציעה עזרי לימוד, מילון ולקסיקון מבית מילון מרים-ובסטר. "אנציקלופדיה בריטניקה און-ליין" הוא אתר אינטרנט הכולל למעלה מ-120,000 ערכים המעודכן באופן קבוע. הוא כולל עדכונים יומיים וקישורים לדיווחי חדשות מהניו יורק טיימס וה-BBC. ניתן לרכוש מנוי שבועי, חודשי או שנתי. אפשרויות הרשמה מיוחדות מוצעות לבתי ספר, מכללות וספריות; מנויים מוסדיים כאלו מהווים חלק נכבד מהכנסותיה של הבריטניקה. הערכים זמינים מעל גבי הרשת, אך רק מספר שורות מתחילת הערך מוצגות חינם. החל מראשית שנת 2007, הערכים של הבריטניקה און-ליין זמינים במלואם בתנאי שהם מקושרים מאתר אחר. קישורים חיצוניים שכאלה משפרים לרוב את דירוגו של הערך בתוצאות מנועי החיפוש. ב-20 בפברואר 2007 הכריזה חברת אנציקלופדיה בריטניקה על פיתוח גרסה של האנציקלופדיה לטלפונים סלולריים, בשיתוף פעולה עם חברת AskMeNow. המשתמשים יוכלו לשלוח שאלה במסרונים, וחברת AskMeNow תריץ חיפוש בגרסה המתומצתת בת 28,000 הערכים של הבריטניקה כדי להחזיר תשובה לשאילתא. מסרונים יומיים שיישלחו לטלפונים מתוכננים אף הם. צוות והנהלה גרסת הדפוס משנת 2007 של המהדורה החמש-עשרה של האנציקלופדיה בריטניקה נכתבה על ידי 4,411 תורמים, רבים מהם בני-סמכא בתחומם, דוגמת מילטון פרידמן, קרל סייגן והמנתח מייקל דבקיי. כרבע מן הכותבים נפטרו, חלקם עוד בשנת 1947 (אלפרד נורת' וייטהד), בעוד שרבע נוספים פרשו. רוב הכותבים (כ-98%) כתבו ערך אחד בלבד; אולם, 64 כתבו שלושה ערכים, 23 - ארבעה, 10 כתבו חמישה ערכים ואילו שמונה כתבו יותר מחמישה ערכים. כותבת שופעת במיוחד היא ד"ר כריסטין סאטון מאוניברסיטת אוקספורד, שכתבה 24 ערכים על פיזיקת חלקיקים. הסינולוג דייל הויברג מכהן כיום כעורך הראשי של האנציקלופדיה בריטניקה. בין קודמיו ניתן למנות את יו צ'ישולם (1902-1924), ג'יימס לואיס גרווין (1926-1932), פרנקלין הנרי הופר (1902-1938), ואלטר יאסט (1938-1960), הארי אשמור (1960-1963), וארן א. פריס (1964–1968, 1969-1975), סר ויליאם הלי (1968–1969), פיליפ ו. גץ (1979-1991) ורוברט מק'הנרי (1992–1997). אניטה וולף ותאודור פאפאס משמשים כיום כסגנית העורך והעורך בפועל, בהתאמה. עם עורכי עבר בפועל נמנים ג'ון ו. דודג' (1950–1964) ופיליפ ו. גץ. האנציקלופדיה בריטניקה שומרת על צוות עורכים הכולל חמישה עורכים בכירים ותשעה עורכי משנה, המפוקחים על ידי דייל הויברג וארבעה אחרים. צוות העורכים מסייע בכתיבת ערכי המיקרופדיה ובחלקים מסוימים של המאקרופדיה. לאנציקלופדיה בריטניקה מועצת עורכים מייעצים, הכוללת כיום ארבעה-עשר מלומדים בעלי-שם: הפרופדיה ותרשים כל הידע האנושי שלה הם פרי עמלם של עשרות עורכים מייעצים תחת הנהגתו של מורטימר ג'. אדלר. כמחציתם נפטרו מאז ועד היום, ובהם כמה מאדריכליו הראשיים של התרשים: רנה דובוס (נ. 1982), לורן אייזלי (נ. 1977), הרולד ד. לסוול (נ. 1978), מארק ואן דורן (נ. 1972), פטר ריצ'י קולדר (נ. 1982) ומורטימר ג'. אדלר (נ. 2001). הפרופדיה מונה את שמותיהם של כמעט 4,000 יועצים שנעשה שימוש בשירותיהם לצורך כתיבת ערכיה הלא-חתומים של המיקרופדיה. בינואר 1996, נרכשה האנציקלופדיה בריטניקה מקרן בנטון על ידי המיליארדר השווייצרי יעקב (ז'אקי) ספרא, המכהן כיום כיושב ראש חבר המנהלים שלה. בשנת 1997, דון יאניאס, חבר ותיק ויועץ השקעות של ספרא, נתמנה למנכ"ל חברת האנציקלופדיה בריטניקה. חברת חדשה, Britannica.com Inc. הוקמה בשנת 1999 על מנת לשקוד על פיתוח גרסאות ממוחשבות של האנציקלופדיה בריטניקה; יאניאס מילא את תפקיד המנכ"ל בחברה החדשה, ואילו משרתו בחברת האנציקלופדיה בריטניקה נותרה ריקה למשך שנתיים נוספות. תקופת כהונתו של יאניאס ב-Britannica.com Inc התאפיינה במשגים רבים ובהפסדים כספיים כבדים. בשנת 2001 הוחלף יאניאס על ידי הישראלי אילן ישועה, שאיחד מחדש את שתי החברות. יאניאס שב מאוחר יותר לעיסוקו בניהול השקעות, אך מוסיף לכהן כחבר במועצת המנהלים של החברה. בשנת 2003, נתמנה היועץ הניהולי לשעבר חורחה אגילר-קאוס לנשיא חברת האנציקלופדיה בריטניקה. קאוס הוא בעל המשרה הבכיר בחברה ומדווח ישירות למועצת המנהלים של הבריטניקה. על אף סגנונו הרך והמלומד, קידם קאוס באגרסיביות רבה שיתופי פעולה עם חברות אחרות ואת מתיחת מותג הבריטניקה למינוף מוצרי חינוך וספרי עיון חדשים, בהמשיכו את האסטרטגיה אותה הגה המנכ"ל אלקן הריסון פאואל עוד בשנות השלושים של המאה העשרים. תחת בעלותו של ספרא נקלעה החברה לקשיים כלכליים, והגיבה על ידי הפחתת מחירי מוצריה ויישום תוכניות התייעלות דרסטיות. על פי דיווח משנת 2003 בניו יורק פוסט, הנהלת הבריטניקה הפסיקה להשתתף בתוכניות הפנסיה של עובדיה ועודדה את השימוש בתמונות חופשיות. שינויים אלה הביאו לתופעות שליליות, כאשר כותבים פרילנסרים נאלצו להמתין עד שישה חודשים להמחאות התשלום על כתיבתם ואילו עובדי הבריטניקה לא זכו להעלאת שכר במשך שנים. אנציקלופדיה בריטניקה היא בעלת רישום כסימן מסחר על השמות "Britannica", "Encyclopædia Britannica", "Macropædia", "Micropædia" ו-"Propædia", כמו גם על סמלילה הוותיק. יחס הקהל והביקורת למן המהדורה השלישית, זכתה האנציקלופדיה בריטניקה לאהדה רבה מצד הקהל והמבקרים. מהדורות רבות, החל בשלישית וכלה בתשיעית, הודפסו ונמכרו באופן פיראטי (תוך הפרת זכויות יוצרים של בעלי האנציקלופדיה) בארצות הברית, החל באנציקלופדיה של דובסון. לכבוד השקת המהדורה הארבע-עשרה של האנציקלופדיה בריטניקה, כינה טיים מגזין את האנציקלופדיה בריטניקה "הפטריארך של הספרייה". באחת הפרסומות לאנציקלופדיה מצוטט הנטורליסט ויליאם ביבי כאומר שהבריטניקה הייתה "מעבר לכל השוואה משום שאין כל מתחרה." הפניות לבריטניקה ניתן למצוא לכל אורך ההיסטוריה של הספרות האנגלית, כדוגמת הסיפור הקצר בכיכוב שרלוק הולמס שכתב ארתור קונאן דויל - "ליגת אדומי-השיער". הסיפור הוזכר בגאווה על ידי ראש-עיריית לונדון, גילברט אינגלפילד, באירועי יובל ה-200 של האנציקלופדיה בריטניקה. לבריטניקה יש מוניטין בקרב הציבור הרחב כטומנת בחובה את כל הידע האנושי. לשם הרחבת השכלתם, אנשים רבים הקדישו את זמנם לקריאת האנציקלופדיה בריטניקה במלואה, משימה שאורכה נע על פי הדיווחים בין 3 ל-22 שנים. כאשר פאת' עלי נעשה לשאה הפרסי בשנת 1797, הוענקה לו במתנה המהדורה השלישית של האנציקלופדיה בריטניקה, שאותה קרא במלואה; בתום משימה זו, הוא הרחיב את תוארו המלכותי כך שיכלול את "השר והאדון המדהים של האנציקלופדיה בריטניקה". הסופר ג'ורג' ברנרד שו טען כי קרא את המהדורה התשיעית בשלמותה - להוציא את ערכי המדע, וריצ'רד בירד נטל עמו את הבריטניקה כחומר קריאה לשהייתו בה חמשת-החודשים בקוטב הדרומי בשנת 1934. מאוחר יותר, א.ג'. ג'ייקובס, עורך בכתב-העת Esquire, קרא את גרסת שנת 2002 של המהדורה החמש-עשרה במלואה, ותיאר את חוויותיו בספרו המצליח משנת 2004, The Know-It-All: One Man's Humble Quest to Become the Smartest Person in the World ("לדעת-הכל: מסעו הענו של אחד האדם במטרה להיות לאדם החכם בעולם"). מעטים עוד יותר קראו שתי מהדורות שונות: הסופר ס.ס. פורסטר ואיימוס אורבן שירק, איש-עסקים אמריקאי, שקרא את המהדורות האחת-עשרה והארבע-עשרה, על ידי הקדשת כשלוש שעות ללילה במשך ארבע שנים וחצי על מנת להשלים את קריאת המהדורה האחת-עשרה. מספר עורכים ראשיים של האנציקלופדיה בריטניקה קראו, ככל הנראה, את כל המהדורה שהייתה באחריותם, למשל ויליאם סמלי (המהדורה הראשונה), ויליאם רוברטסון סמית' (המהדורה התשיעית) וואלטר יאסט (המהדורה הארבע-עשרה). האנציקלופדיה בריטניקה זכתה בפרסים רבים. המהדורה המקוונת של האנציקלופדיה בריטניקה זכתה בפרס קודי בגין "שירותי המידע ללקוח המקוונים הטובים ביותר" לשנת 2005; פרסי הקודי מוענקים בכל שנה על ידי ארגון תעשיית המידע והתוכנה כאות הוקרה למוצרים הטובים ביותר בקטגוריות שונות של תוכנה. בשנת 2006, הגיעה הבריטניקה שוב למועמדות סופית לפרס. בדומה לכך, גרסאות ה-CD-ROM וה-DVD של הבריטניקה זכו בשנת 2004 בפרס ההישג הראוי לציון מטעם ארגון המוציאים לאור החינוכיים, ובפרסי קודי לשנים 2001 ו-2002. ניתן להצהיר בלא חשש לסתירה שהמהדורה החמש-עשרה של האנציקלופדיה בריטניקה מעניקה לעולם הלא-מערבי - תרבות והתפתחויות חברתיות ומדעיות יותר תשומת-לב מכל אנציקלופדיה אחרת בשפה האנגלית הנמכרת בשוק כיום. בתור אנציקלופדיה כללית, האנציקלופדיה בריטניקה שואפת לתאר מגוון רחב ככל האפשר של תחומים. התחומים נבחרים בחלקם על פי "תרשים כל הידע האנושי" שבכרך הפרופדיה. עיקר הבריטניקה מוקדש לגאוגרפיה (26% מהמאקרופדיה), ערכי אישים (14%), ביולוגיה ורפואה (11%), ספרות (7%), פיזיקה ואסטרונומיה (6%), דתות (5%), אמנויות (4%), פילוסופיה מערבית (4%) ומשפטים (3%). מחקר משלים על המיקרופדיה העלה תוצאות לפיהן ערכי הגאוגרפיה היוו כ-25% מהערכים, מדעים מדויקים 18%, מדעי החברה 17%, ערכי אישים 17% וכל שאר מדעי הרוח 25%. בביקורת משנת 1992, פסק אחד המבקרים כי "הטווח, העומק ורוחב-הדעת בכיסוי התחומים [על ידי הבריטניקה] אינם בני-תחרות עם אף אנציקלופדיה כללית אחרת." האנציקלופדיה בריטניקה אינה מכסה נושאים שונים בפירוט זהה; כך למשל, כל דת הבודהיזם ורוב הדתות האחרות בעולם נסקרות בערך מאקרופדיה אחד ויחיד, בעוד שארבעה-עשר ערכים נדרשו לכיסוי הנצרות, כמעט מחצית מכלל ערכי הדתות. למרות זאת, האנציקלופדיה בריטניקה כונתה "המוטה פחות" מבין האנציקלופדיות הכלליות המשווקות לקורא המערבי וקצרה שבחים על ערכיה הביוגרפיים על נשים חשובות בכל הזמנים. גרסאות מוקדמות מסוימות של האנציקלופדיה בריטניקה זכו לביקורות בגין אי-דיוקים, הטיות וכותבים לא מוסמכים; באותה המידה, אף דיוק העובדות שבמהדורה הנוכחית של הבריטניקה הוטל בספק, הגם שדברי ביקורת שכאלה זכו למענה מצד הנהלת האנציקלופדיה בריטניקה. למרות המוניטין המוצלח ואהדת הציבור, האנציקלופדיה בריטניקה ספגה ביקורות קשות, במיוחד כשמהדורותיה נעשו למיושנות. בשל יוקר ההפקה של מהדורה חדשה לגמרי של האנציקלופדיה בריטניקה, עורכיה לאורך ההיסטוריה השתדלו לדחות זאת ככל האפשר (25 שנה בממוצע, כנזכר לעיל). לדוגמה, על אף מדיניות העדכון המתמיד, המהדורה הארבע-עשרה הייתה למיושנת למדי בתום 35 שנים (1929-1964). כאשר הארווי איינביינדר תיאר את כישלונותיה בספרו משנת 1964, The Myth of the Britannica ("המיתוס של הבריטניקה"), עודד הדבר את צוות האנציקלופדיה להתחיל להפיק את המהדורה החמש-עשרה, משימה שארכה כ-10 שנות עבודה. אף היום קשה לשמור על עדכניותה של האנציקלופדיה בריטניקה; אחד המבקרים כתב ש"אין זה קשה למצוא ערכים מיושנים או דורשים עדכון", בהעירו שערכי המאקרופדיה הארוכים נוטים להתיישן בקלות רבה יותר מערכי המיקרופדיה הקצרים. המידע במיקרופדיה אינו תואם לעיתים לזה המופיע בערך המאקרופדיה המקביל לו, בעיקר בשל כישלון בעדכון אחד מהם. רשימות המקורות של ערכי המאקרופדיה זכו לביקורות בשל חוסר עדכניותן המובהקת, אף יותר מהערכים שבסופם הן מופיעות. עם מחברי ערכי הבריטניקה נמנים כאלה שהיו נודעים למדי, ואף בני-סמכא בעלי שם עולמי, כגון אלברט איינשטיין, מארי קירי ולאון טרוצקי. אולם, היו מבין הכותבים שספגו ביקורת על היעדר מומחיות מספקת: בפזיזות מזעזעת כמעט, [כותב הערך בבריטניקה, מר פיליפס] סוקר את תחום ההיסטוריה האירופית בכללותו - פוליטית, חברתית וכנסייתית... דא עקא, חיבור זה נעדר כותב בר-סמכא. דבר זה, בנוסף - הסתמכות זו על תעוזה עריכתית במקום על לימוד - עשוי להחשב ל-"אמריקניזציה": משום שלבטח אין דבר שהוזיל יותר את מידת הלמדנות של האנציקלופדיות האמריקאיות שלנו. ברי-סמכא רבים, החל בווירג'יניה וולף וכלה בפרופסורים, העבירו ביקורת קשה על הבריטניקה כמקדמת עמדות מיושנות ובורגניות בנושאי אמנות, ספרות ומדעי-החברה. כך למשל, המהדורה האחת-עשרה של האנציקלופדיה בריטניקה הואשמה בהזנחת עבודתו של זיגמונד פרויד. פרופסור בן-זמנו מאוניברסיטת קורנל, אדוארד טיצ'נר, אמר: "הבריטניקה החדשה אינה משקפת את האטמוספירה הפסיכולוגית של הדור והתקופה... על אף הילת הסמכא, ועל אף העבודה המדוקדקת של הצוות, עיקר ערכי המשנה בנושאי פסיכולוגיה כללית... אינם עומדים בדרישות הקורא הנבון." האנציקלופדיה בריטניקה זוכה לעיתים לביקורת על בחירות עורכיה. בהינתן גודלה הקבוע במידה רבה, נדרשו עורכי האנציקלופדיה לצמצמם או להסיר כליל תחומים מסוימים על מנת לפנות מקום לאחרים, דבר שהביא לכמה החלטות שנויות-במחלוקת. הגרסה הראשונה של המהדורה החמש-עשרה של האנציקלופדיה בריטניקה (1974-1985) ספגה האשמות בשל הצמצום הניכר עד המוחלט של כיסוי התחומים הבאים: ספרות ילדים, עיטורים צבאיים והמשורר הצרפתי ז'ואקן די בלה; הועלו אף האשמות על טעויות עריכה, דוגמת סידור בלתי-עקבי של ערכי האישים היפניים. ביטול מפתח העניינים ספג גינויים רחבי היקף, כמו גם החלוקה השרירותית למראה של הערכים לתוך המיקרופדיה והמאקרופדיה. בסכמו, קרא אחד המבקרים לגרסה הראשונה של המהדורה החמש-עשרה "כישלון איכותי... [ש]עוסק יותר בלהטוטים צורניים מאשר בשימור מידע." מאוחר יותר, מבקרים מאיגוד הספריות האמריקאי הופתעו לגלות שערכים מרחיבי-דעת במיוחד הועלמו מהמאקרופדיה גרסת 1992, ובהם ערך על פסיכולוגיה. כותבי האנציקלופדיה בריטניקה ביצעו לעיתים טעויות ואף גילו היעדר ידע מדעי מספק. דוגמה ידועה לשמצה מימיה הראשונים של הבריטניקה היא דחיית תאוריית הכבידה של אייזק ניוטון על ידי ג'ורג' גלייג, העורך הראשי של המהדורה השלישית (1788-1797), שכתב כי הכבידה נגרמת על ידי היסוד הקלאסי - האש. דוגמה מאוחרת יותר היא הערך המאמין על רוחות רפאים במהדורה האחת-עשרה (1911), אמונה טפלה שהייתה אהודה במיוחד באותם הימים; הערך מצהיר כי "נותר סיכוי שסוכנות כלשהי שטבעה אינו נחקר, למצער במקרים מסוימים, אכן פועלת." עם זאת, האנציקלופדיה בריטניקה הגנה בהחלטיות רבה על גישתה המדעית כלפי נושאים אמוציונליים, כשם שנעשה בערכיו של ויליאם רוברטסון סמית' על הדת במהדורה התשיעית, במיוחד הערך שהצהיר כי התנ"ך אינו מדויק היסטורית (1875). על-פי תקנים בני-זמננו, מהדורות העבר של האנציקלופדיה בריטניקה חטאו בגזענות ובסקסיזם. המהדורה האחת-עשרה מתארת את הקו קלוקס קלאן כארגון שהגן על הגזע הלבן והשיב את הסדר לדרום ארצות הברית לאחר מלחמת האזרחים האמריקאית, בצטטה את הצורך "לשלוט בכושים (negro)", וכן "למנוע כל ערבוב בין הגזעים" ואף "ההתרחשות הנפוצה של פשע האונס על ידי גברים כושים כלפי נשים לבנות." בדומה, הערך על "ציוויליזציה" טוען בזכות אאוגניקה, בהצהירו כי יהיה זה אי-רציונלי ל"הפרות סדרים נמוכים של אינטליגנציה, להזין את מעמדות האביונים, הדפקטיבם והפושעים.. שכיום מהווים מכשול כה מאיים להתקדמות הגזעית." המהדורה האחת-עשרה אינה כוללת ערך על מארי קירי, הגם שזכתה בפרס נובל לפיזיקה עוד בשנת 1903 ובפרס נובל בכימיה בשנת 1911, אם כי היא מוזכרת קצרות בערך על אודות בעלה, פייר קירי. האנציקלופדיה בריטניקה העסיקה מספר רב של נשים בצוות העורכים שלה, שכתבו מאות ערכים עליהן לא זכו לכל קרדיט. בשנת 1912, ל.ק. קרפינסקי מתח ביקורת על המהדורה האחת-עשרה בגין אי-דיוקים רבים בערכים על ההיסטוריה של המתמטיקה, שאף אחד מהם לא נכתב על ידי מומחה מן התחום. בשנת 1917, מבקר-האמנות וילארד הנטינגטון רייט פרסם ספר, Misinforming a Nation (מטעים אומה), ובו הוצגו לראווה אי-דיוקים רבים והטיה אנגלית של המהדורה האחת-עשרה, במיוחד בתחום מדעי הרוח. רבות מהערותיו של רייט זכו למענה במהדורות מאוחרות יותר של הבריטניקה. ברם, ספרו הוקע כפולמוסי על ידי מספר מבקרים בני-זמננו; כך למשל, הניו יורק טיימס כתב כי "מזג רע-לב ורדוד... ממלא את הספר", בעוד שהניו ריפבליק קבע, "מצער שמטרתו הלא יודעת רחם של רייט אינה מגובה ברוח מדעית ובהצדקה אובייקטיבית ממשית לביקורתו." מבקר אחר, הכומר לשעבר והסופר האנגלי ג'וזף מק'קייב, טען כי הבריטניקה הושפעה מלחצי הכנסייה הקתולית, בספרו, Lies And Fallacies Of The Encyclopedia Britannica (שקרים ופרכות באנציקלופדיה בריטניקה), שיצא לאור בשנת 1947. הנהלת האנציקלופדיה בריטניקה טענה תמיד כי טעויות הן בלתי נמנעות כשמדובר באנציקלופדיה בסדר גודל שכזה. ג'ורג' גלייג, עורכה הראשי של המהדורה השלישית (1788–1797), כתב בהתייחס אליה כי "שלמות נראית כאינה תואמת את טבעם של חיבורים הנבנים על בסיס תוכנית שכזו, וחובקים מגוון כה רחב של נושאים." במרץ 2006 נכתב בבריטניקה כי "איננו מנסים בשום צורה שהיא לרמוז כי הבריטניקה חפה משגיאות; מעולם לא העלנו טענה שכזאת." דעה זו מתבטאת היטב בדבריו של העורך הראשון, ויליאם סמלי: באשר לשגיאות בכללותן, בין אם הן כאלו הנופלות תחת ההגדרה של טעות שכלית, טיפוגראפית או מקרית, אנו סמוכים ובטוחים ביכולתנו להצביע על טעויות רבות יותר משיוכל כל מבקר. בעלי ההיכרות עם הקשיים הרבים מספור הכרוכים בהבאת עבודה בהיקף כזה לשלמות, ודאי ידעו להביע את תודתם. לאלו אנו ממתינים, וחשים סיפוק רב מהשיפוט המתבטא ברכישתם. תחרות משום שהאנציקלופדיה בריטניקה היא אנציקלופדיה כללית, היא איננה שואפת להתחרות באנציקלופדיות תחומיות דוגמת "האנציקלופדיה של המתמטיקה" או "מילון ימי הביניים", היכולים להרחיב את היריעה בנושאים שבהם הם מתמקדים. מתחרותיה העיקריות היו אנציקלופדיות כלליות אחרות. בשנותיה הראשונות, מתחרתה העיקרית של האנציקלופדיה בריטניקה הייתה האנציקלופדיה של צ'יימברס ומיד אחר כך הציקלופדיה של ריס והאנציקלופדיה מטרופוליטנה של קולרידג'. במאה העשרים, מתחרים מצליחים היו בין השאר האנציקלופדיה של קולייר, האנציקלופדיה אמריקנה וה-World Book Encyclopedia. כל אחת מאנציקלופדיות אלה התברכה בתכונות שעשו אותה איכותית במיוחד, כגון כתיבה בהירה ביותר או איורים מעולים. אף על פי כן, החל במהדורתה התשיעית ואילך, האנציקלופדיה בריטניקה נחשבה ככלל לאנציקלופדיה האמינה ביותר מבין כל האנציקלופדיות הכלליות בשפה האנגלית, במיוחד בשל תחום הכיסוי הרחב שלה וכותביה בעלי-השם. ברם, מהדורת הדפוס של האנציקלופדיה בריטניקה יקרה במידה ניכרת ממתחרותיה. למן ראשית שנות התשעים של המאה העשרים, נאלצה האנציקלופדיה בריטניקה להתמודד עם מקורות מידע ממוחשבים. רשת האינטרנט צמחה להיות מקור מידע מקובל בעבור אנשים רבים, ומספקת גישה פשוטה למקורות ראשוניים אמינים ולדעות-מומחים, הודות ליוזמות כגון Google Books או היוזמה של MIT, שפתח לציבור הרחב את תכניו הלימודיים, וספריית PubMed של הספרייה הלאומית האמריקאית לרפואה. באופן כללי, רשת האינטרנט נוטה לספק כיסוי עדכני יותר לאירועים מאשר העיתונות המודפסת, הודות לקלות שבה ניתן לעדכן את התכנים באינטרנט. בתחומים המשתנים תדיר דוגמת מדע, טכנולוגיה, פוליטיקה, תרבות והיסטוריה מודרנית, האנציקלופדיה בריטניקה התקשתה לשמור על עדכניותה, בעיה שעמד על טיבה לראשונה העורך הראשי לשעבר ואלטר יאסט. הגם שהאנציקלופדיה בריטניקה זמינה כיום הן מעל גבי מדיה דיגיטלית והן מעל גבי רשת האינטרנט, הרי שבכורתה בעולם זה מאוימת על ידי אנציקלופדיות מקוונות כגון אנקרטה לשעבר (עד לסגירתה בין השנים 2009–2011) וויקיפדיה. בעבר הייתה אנקרטה המתחרה הבולטת ביותר לאנציקלופדיה בריטניקה בתחום האנציקלופדיות הנמכרות מעל גבי CD/DVD-ROM. שתי האנציקלופדיות נעו באותו טווח מחירים, כאשר האנציקלופדיה בריטניקה "Ultimate" לשנת 2007 ב-CD או DVD נמכרת ב-50 דולר בעוד שהאנקרטה פרימיום לשנת 2007 נמכרה ב-45 דולרים. בעוד שהבריטניקה הייתה כוללת למעלה מ-100,000 ערכים, ובנוסף מילון ואגרון של מרים-וובסטר (בארצות הברית בלבד), ומציעה גרסאות לבית הספר היסודי ולתיכון. אנקרטה כללה 66,000 ערכים, תוכנת ניווט חזותית ידידותית למשתמש, מפות אינטראקטיביות וכן כלי מתמטיקה, שפה וסייעים להכנת שיעורי בית, מילון לאנגלית אמריקאית ובריטית, ומהדורה לנוער. בדומה לאנקרטה, האנציקלופדיה בריטניקה ספגה ביקורת על הטיה לטובת קהלים בארצות הברית; ערכים הקשורים בבריטניה מעודכנים בתדירות נמוכה יותר, מפות של ארצות הברית מפורטות יותר מאלו של ארצות אחרות, ואין בה מילון לאנגלית בריטית. בדומה לבריטניקה, אנקרטה הייתה זמינה מעל גבי רשת האינטרנט בשיטת המנויים, הגם שחלק מהתכנים היו פתוחים לצפייה ללא תשלום. עם צמיחתה של ויקיפדיה בתחילת המאה ה-21 היא הפכה למתחרה העיקרית של אנציקלופדיה בריטניקה. האנציקלופדיה בריטניקה הושוותה עם אנציקלופדיות מודפסות אחרות, הן ברמה האיכותנית והן מן הבחינה הכמותית. השוואה ידועה במיוחד היא זו של קנת' קיסטר, שביצע השוואה איכותית וכמותית של הבריטניקה עם שתי אנציקלופדיות, האנציקלופדיה של קולייר והאנציקלופדיה אמריקנה. מן הבחינה האיכותית, עשרה ערכים נבחרו אקראית (מילה, צ'ארלס דרו, גלילאו, פיליפ גלאס, מחלת לב, IQ, דוב פנדה, הטרדה מינית, תכריכי טורינו ואוזבקיסטן) וציונים באותיות (A-D ו-F) ניתנו על בסיס ארבע קטגוריות: רוחב הכיסוי, דיוק, בהירות ועדכניות. בכל ארבע הקטגוריות ובעבור כל שלוש האנציקלופדיות, הציון הממוצע נע בין B- לבין B+, בעיקר בשל העובדה שבאף אחת מהאנציקלופדיות לא היה ערך בנושא הטרדה מינית בשנת 1994. בקטגוריית הדיוק, קיבלה הבריטניקה D אחד ושמונה A-ים. האנציקלופדיה אמריקנה קיבלה שמונה A-ים והאנציקלופדיה של קולייר קיבלה D אחד ושבעה A-ים; אשר על כן, קיבלה האנציקלופדיה בריטניקה ציון ממוצע של 92% בדיוק בהשוואה ל-95% של האמריקנה ו-92% של קולייר. הבריטניקה של 1994 הורשעה בפרסום עלילת השמצה על צ'ארלס דאו שהופרכה זמן רב קודם לכן. בקטגוריית העדכניות קיבלה הבריטניקה ממוצע של 86% בהשוואה ל-90% אצל האמריקנה ו-85% אצל קולייר. לאחר השוואה איכותנית מעמיקה יותר בין כל השלוש, המליץ קיסטר על האנציקלופדיה של קולייר כעל האנציקלופדיה העליונה, בעיקר הודות לסגנון הכתיבה, לנייטרליות וליכולת הניווט. כתב העת Nature ערך השוואה בין בריטניקה לוויקיפדיה מבחינת אמינות הערכים (ההשוואה נעשתה בעשרות ערכים מתחומים שונים, בהם עקרון ארכימדס, מחלת קרויצפלד-יעקב, ענן, ליפיד, דימיטרי מנדלייב, בלוטת התריס וקווארק), והתברר שאין הבדל משמעותי בין האנציקלופדיות. רשימת המהדורות קישורים חיצוניים הערות שוליים |
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[SOURCE: https://en.wikipedia.org/wiki/Joke#cite_note-FOOTNOTEEllis20022-48] | [TOKENS: 8460] |
Contents Joke A joke is a display of humour in which words are used within a specific and well-defined narrative structure to make people laugh and is usually not meant to be interpreted literally. It usually takes the form of a story, often with dialogue, and ends in a punch line, whereby the humorous element of the story is revealed; this can be done using a pun or other type of word play, irony or sarcasm, logical incompatibility, hyperbole, or other means. Linguist Robert Hetzron offers the definition: A joke is a short humorous piece of oral literature in which the funniness culminates in the final sentence, called the punchline… In fact, the main condition is that the tension should reach its highest level at the very end. No continuation relieving the tension should be added. As for its being "oral," it is true that jokes may appear printed, but when further transferred, there is no obligation to reproduce the text verbatim, as in the case of poetry. It is generally held that jokes benefit from brevity, containing no more detail than is needed to set the scene for the punchline at the end. In the case of riddle jokes or one-liners, the setting is implicitly understood, leaving only the dialogue and punchline to be verbalised. However, subverting these and other common guidelines can also be a source of humour—the shaggy dog story is an example of an anti-joke; although presented as a joke, it contains a long drawn-out narrative of time, place and character, rambles through many pointless inclusions and finally fails to deliver a punchline. Jokes are a form of humour, but not all humour is in the form of a joke. Some humorous forms which are not verbal jokes are: involuntary humour, situational humour, practical jokes, slapstick and anecdotes. Identified as one of the simple forms of oral literature by the Dutch linguist André Jolles, jokes are passed along anonymously. They are told in both private and public settings; a single person tells a joke to his friend in the natural flow of conversation, or a set of jokes is told to a group as part of scripted entertainment. Jokes are also passed along in written form or, more recently, through the internet. Stand-up comics, comedians and slapstick work with comic timing and rhythm in their performance, and may rely on actions as well as on the verbal punchline to evoke laughter. This distinction has been formulated in the popular saying "A comic says funny things; a comedian says things funny".[note 1] History in print Jokes do not belong to refined culture, but rather to the entertainment and leisure of all classes. As such, any printed versions were considered ephemera, i.e., temporary documents created for a specific purpose and intended to be thrown away. Many of these early jokes deal with scatological and sexual topics, entertaining to all social classes but not to be valued and saved.[citation needed] Various kinds of jokes have been identified in ancient pre-classical texts.[note 2] The oldest identified joke is an ancient Sumerian proverb from 1900 BC containing toilet humour: "Something which has never occurred since time immemorial; a young woman did not fart in her husband's lap." Its records were dated to the Old Babylonian period and the joke may go as far back as 2300 BC. The second oldest joke found, discovered on the Westcar Papyrus and believed to be about Sneferu, was from Ancient Egypt c. 1600 BC: "How do you entertain a bored pharaoh? You sail a boatload of young women dressed only in fishing nets down the Nile and urge the pharaoh to go catch a fish." The tale of the three ox drivers from Adab completes the three known oldest jokes in the world. This is a comic triple dating back to 1200 BC Adab. It concerns three men seeking justice from a king on the matter of ownership over a newborn calf, for whose birth they all consider themselves to be partially responsible. The king seeks advice from a priestess on how to rule the case, and she suggests a series of events involving the men's households and wives. The final portion of the story (which included the punch line), has not survived intact, though legible fragments suggest it was bawdy in nature. Jokes can be notoriously difficult to translate from language to language; particularly puns, which depend on specific words and not just on their meanings. For instance, Julius Caesar once sold land at a surprisingly cheap price to his lover Servilia, who was rumoured to be prostituting her daughter Tertia to Caesar in order to keep his favour. Cicero remarked that "conparavit Servilia hunc fundum tertia deducta." The punny phrase, "tertia deducta", can be translated as "with one-third off (in price)", or "with Tertia putting out." The earliest extant joke book is the Philogelos (Greek for The Laughter-Lover), a collection of 265 jokes written in crude ancient Greek dating to the fourth or fifth century AD. The author of the collection is obscure and a number of different authors are attributed to it, including "Hierokles and Philagros the grammatikos", just "Hierokles", or, in the Suda, "Philistion". British classicist Mary Beard states that the Philogelos may have been intended as a jokester's handbook of quips to say on the fly, rather than a book meant to be read straight through. Many of the jokes in this collection are surprisingly familiar, even though the typical protagonists are less recognisable to contemporary readers: the absent-minded professor, the eunuch, and people with hernias or bad breath. The Philogelos even contains a joke similar to Monty Python's "Dead Parrot Sketch". During the 15th century, the printing revolution spread across Europe following the development of the movable type printing press. This was coupled with the growth of literacy in all social classes. Printers turned out Jestbooks along with Bibles to meet both lowbrow and highbrow interests of the populace. One early anthology of jokes was the Facetiae by the Italian Poggio Bracciolini, first published in 1470. The popularity of this jest book can be measured on the twenty editions of the book documented alone for the 15th century. Another popular form was a collection of jests, jokes and funny situations attributed to a single character in a more connected, narrative form of the picaresque novel. Examples of this are the characters of Rabelais in France, Till Eulenspiegel in Germany, Lazarillo de Tormes in Spain and Master Skelton in England. There is also a jest book ascribed to William Shakespeare, the contents of which appear to both inform and borrow from his plays. All of these early jestbooks corroborate both the rise in the literacy of the European populations and the general quest for leisure activities during the Renaissance in Europe. The practice of printers using jokes and cartoons as page fillers was also widely used in the broadsides and chapbooks of the 19th century and earlier. With the increase in literacy in the general population and the growth of the printing industry, these publications were the most common forms of printed material between the 16th and 19th centuries throughout Europe and North America. Along with reports of events, executions, ballads and verse, they also contained jokes. Only one of many broadsides archived in the Harvard library is described as "1706. Grinning made easy; or, Funny Dick's unrivalled collection of curious, comical, odd, droll, humorous, witty, whimsical, laughable, and eccentric jests, jokes, bulls, epigrams, &c. With many other descriptions of wit and humour." These cheap publications, ephemera intended for mass distribution, were read alone, read aloud, posted and discarded. There are many types of joke books in print today; a search on the internet provides a plethora of titles available for purchase. They can be read alone for solitary entertainment, or used to stock up on new jokes to entertain friends. Some people try to find a deeper meaning in jokes, as in "Plato and a Platypus Walk into a Bar... Understanding Philosophy Through Jokes".[note 3] However a deeper meaning is not necessary to appreciate their inherent entertainment value. Magazines frequently use jokes and cartoons as filler for the printed page. Reader's Digest closes out many articles with an (unrelated) joke at the bottom of the article. The New Yorker was first published in 1925 with the stated goal of being a "sophisticated humour magazine" and is still known for its cartoons. Telling jokes Telling a joke is a cooperative effort; it requires that the teller and the audience mutually agree in one form or another to understand the narrative which follows as a joke. In a study of conversation analysis, the sociologist Harvey Sacks describes in detail the sequential organisation in the telling of a single joke. "This telling is composed, as for stories, of three serially ordered and adjacently placed types of sequences … the preface [framing], the telling, and the response sequences." Folklorists expand this to include the context of the joking. Who is telling what jokes to whom? And why is he telling them when? The context of the joke-telling in turn leads into a study of joking relationships, a term coined by anthropologists to refer to social groups within a culture who engage in institutionalised banter and joking. Framing is done with a (frequently formulaic) expression which keys the audience in to expect a joke. "Have you heard the one…", "Reminds me of a joke I heard…", "So, a lawyer and a doctor…"; these conversational markers are just a few examples of linguistic frames used to start a joke. Regardless of the frame used, it creates a social space and clear boundaries around the narrative which follows. Audience response to this initial frame can be acknowledgement and anticipation of the joke to follow. It can also be a dismissal, as in "this is no joking matter" or "this is no time for jokes". The performance frame serves to label joke-telling as a culturally marked form of communication. Both the performer and audience understand it to be set apart from the "real" world. "An elephant walks into a bar…"; a person sufficiently familiar with both the English language and the way jokes are told automatically understands that such a compressed and formulaic story, being told with no substantiating details, and placing an unlikely combination of characters into an unlikely setting and involving them in an unrealistic plot, is the start of a joke, and the story that follows is not meant to be taken at face value (i.e. it is non-bona-fide communication). The framing itself invokes a play mode; if the audience is unable or unwilling to move into play, then nothing will seem funny. Following its linguistic framing the joke, in the form of a story, can be told. It is not required to be verbatim text like other forms of oral literature such as riddles and proverbs. The teller can and does modify the text of the joke, depending both on memory and the present audience. The important characteristic is that the narrative is succinct, containing only those details which lead directly to an understanding and decoding of the punchline. This requires that it support the same (or similar) divergent scripts which are to be embodied in the punchline. The punchline is intended to make the audience laugh. A linguistic interpretation of this punchline/response is elucidated by Victor Raskin in his Script-based Semantic Theory of Humour. Humour is evoked when a trigger contained in the punchline causes the audience to abruptly shift its understanding of the story from the primary (or more obvious) interpretation to a secondary, opposing interpretation. "The punchline is the pivot on which the joke text turns as it signals the shift between the [semantic] scripts necessary to interpret [re-interpret] the joke text." To produce the humour in the verbal joke, the two interpretations (i.e. scripts) need to both be compatible with the joke text and opposite or incompatible with each other. Thomas R. Shultz, a psychologist, independently expands Raskin's linguistic theory to include "two stages of incongruity: perception and resolution." He explains that "… incongruity alone is insufficient to account for the structure of humour. […] Within this framework, humour appreciation is conceptualized as a biphasic sequence involving first the discovery of incongruity followed by a resolution of the incongruity." In the case of a joke, that resolution generates laughter. This is the point at which the field of neurolinguistics offers some insight into the cognitive processing involved in this abrupt laughter at the punchline. Studies by the cognitive science researchers Coulson and Kutas directly address the theory of script switching articulated by Raskin in their work. The article "Getting it: Human event-related brain response to jokes in good and poor comprehenders" measures brain activity in response to reading jokes. Additional studies by others in the field support more generally the theory of two-stage processing of humour, as evidenced in the longer processing time they require. In the related field of neuroscience, it has been shown that the expression of laughter is caused by two partially independent neuronal pathways: an "involuntary" or "emotionally driven" system and a "voluntary" system. This study adds credence to the common experience when exposed to an off-colour joke; a laugh is followed in the next breath by a disclaimer: "Oh, that's bad…" Here the multiple steps in cognition are clearly evident in the stepped response, the perception being processed just a breath faster than the resolution of the moral/ethical content in the joke. Expected response to a joke is laughter. The joke teller hopes the audience "gets it" and is entertained. This leads to the premise that a joke is actually an "understanding test" between individuals and groups. If the listeners do not get the joke, they are not understanding the two scripts which are contained in the narrative as they were intended. Or they do "get it" and do not laugh; it might be too obscene, too gross or too dumb for the current audience. A woman might respond differently to a joke told by a male colleague around the water cooler than she would to the same joke overheard in a women's lavatory. A joke involving toilet humour may be funnier told on the playground at elementary school than on a college campus. The same joke will elicit different responses in different settings. The punchline in the joke remains the same, however, it is more or less appropriate depending on the current context. The context explores the specific social situation in which joking occurs. The narrator automatically modifies the text of the joke to be acceptable to different audiences, while at the same time supporting the same divergent scripts in the punchline. The vocabulary used in telling the same joke at a university fraternity party and to one's grandmother might well vary. In each situation, it is important to identify both the narrator and the audience as well as their relationship with each other. This varies to reflect the complexities of a matrix of different social factors: age, sex, race, ethnicity, kinship, political views, religion, power relationships, etc. When all the potential combinations of such factors between the narrator and the audience are considered, then a single joke can take on infinite shades of meaning for each unique social setting. The context, however, should not be confused with the function of the joking. "Function is essentially an abstraction made on the basis of a number of contexts". In one long-term observation of men coming off the late shift at a local café, joking with the waitresses was used to ascertain sexual availability for the evening. Different types of jokes, going from general to topical into explicitly sexual humour signalled openness on the part of the waitress for a connection. This study describes how jokes and joking are used to communicate much more than just good humour. That is a single example of the function of joking in a social setting, but there are others. Sometimes jokes are used simply to get to know someone better. What makes them laugh, what do they find funny? Jokes concerning politics, religion or sexual topics can be used effectively to gauge the attitude of the audience to any one of these topics. They can also be used as a marker of group identity, signalling either inclusion or exclusion for the group. Among pre-adolescents, "dirty" jokes allow them to share information about their changing bodies. And sometimes joking is just simple entertainment for a group of friends. Relationships The context of joking in turn leads to a study of joking relationships, a term coined by anthropologists to refer to social groups within a culture who take part in institutionalised banter and joking. These relationships can be either one-way or a mutual back and forth between partners. The joking relationship is defined as a peculiar combination of friendliness and antagonism. The behaviour is such that in any other social context it would express and arouse hostility; but it is not meant seriously and must not be taken seriously. There is a pretence of hostility along with a real friendliness. To put it in another way, the relationship is one of permitted disrespect. Joking relationships were first described by anthropologists within kinship groups in Africa. But they have since been identified in cultures around the world, where jokes and joking are used to mark and reinforce appropriate boundaries of a relationship. Electronic The advent of electronic communications at the end of the 20th century introduced new traditions into jokes. A verbal joke or cartoon is emailed to a friend or posted on a bulletin board; reactions include a replied email with a :-) or LOL, or a forward on to further recipients. Interaction is limited to the computer screen and for the most part solitary. While preserving the text of a joke, both context and variants are lost in internet joking; for the most part, emailed jokes are passed along verbatim. The framing of the joke frequently occurs in the subject line: "RE: laugh for the day" or something similar. The forward of an email joke can increase the number of recipients exponentially. Internet joking forces a re-evaluation of social spaces and social groups. They are no longer only defined by physical presence and locality, they also exist in the connectivity in cyberspace. "The computer networks appear to make possible communities that, although physically dispersed, display attributes of the direct, unconstrained, unofficial exchanges folklorists typically concern themselves with". This is particularly evident in the spread of topical jokes, "that genre of lore in which whole crops of jokes spring up seemingly overnight around some sensational event … flourish briefly and then disappear, as the mass media move on to fresh maimings and new collective tragedies". This correlates with the new understanding of the internet as an "active folkloric space" with evolving social and cultural forces and clearly identifiable performers and audiences. A study by the folklorist Bill Ellis documented how an evolving cycle was circulated over the internet. By accessing message boards that specialised in humour immediately following the 9/11 disaster, Ellis was able to observe in real-time both the topical jokes being posted electronically and responses to the jokes. Previous folklore research has been limited to collecting and documenting successful jokes, and only after they had emerged and come to folklorists' attention. Now, an Internet-enhanced collection creates a time machine, as it were, where we can observe what happens in the period before the risible moment, when attempts at humour are unsuccessful Access to archived message boards also enables us to track the development of a single joke thread in the context of a more complicated virtual conversation. Joke cycles A joke cycle is a collection of jokes about a single target or situation which displays consistent narrative structure and type of humour. Some well-known cycles are elephant jokes using nonsense humour, dead baby jokes incorporating black humour, and light bulb jokes, which describe all kinds of operational stupidity. Joke cycles can centre on ethnic groups, professions (viola jokes), catastrophes, settings (…walks into a bar), absurd characters (wind-up dolls), or logical mechanisms which generate the humour (knock-knock jokes). A joke can be reused in different joke cycles; an example of this is the same Head & Shoulders joke refitted to the tragedies of Vic Morrow, Admiral Mountbatten and the crew of the Challenger space shuttle.[note 4] These cycles seem to appear spontaneously, spread rapidly across countries and borders only to dissipate after some time. Folklorists and others have studied individual joke cycles in an attempt to understand their function and significance within the culture. Joke cycles circulated in the recent past include: As with the 9/11 disaster discussed above, cycles attach themselves to celebrities or national catastrophes such as the death of Diana, Princess of Wales, the death of Michael Jackson, and the Space Shuttle Challenger disaster. These cycles arise regularly as a response to terrible unexpected events which command the national news. An in-depth analysis of the Challenger joke cycle documents a change in the type of humour circulated following the disaster, from February to March 1986. "It shows that the jokes appeared in distinct 'waves', the first responding to the disaster with clever wordplay and the second playing with grim and troubling images associated with the event…The primary social function of disaster jokes appears to be to provide closure to an event that provoked communal grieving, by signalling that it was time to move on and pay attention to more immediate concerns". The sociologist Christie Davies has written extensively on ethnic jokes told in countries around the world. In ethnic jokes he finds that the "stupid" ethnic target in the joke is no stranger to the culture, but rather a peripheral social group (geographic, economic, cultural, linguistic) well known to the joke tellers. So Americans tell jokes about Polacks and Italians, Germans tell jokes about Ostfriesens, and the English tell jokes about the Irish. In a review of Davies' theories it is said that "For Davies, [ethnic] jokes are more about how joke tellers imagine themselves than about how they imagine those others who serve as their putative targets…The jokes thus serve to center one in the world – to remind people of their place and to reassure them that they are in it." A third category of joke cycles identifies absurd characters as the butt: for example the grape, the dead baby or the elephant. Beginning in the 1960s, social and cultural interpretations of these joke cycles, spearheaded by the folklorist Alan Dundes, began to appear in academic journals. Dead baby jokes are posited to reflect societal changes and guilt caused by widespread use of contraception and abortion beginning in the 1960s.[note 5] Elephant jokes have been interpreted variously as stand-ins for American blacks during the Civil Rights Era or as an "image of something large and wild abroad in the land captur[ing] the sense of counterculture" of the sixties. These interpretations strive for a cultural understanding of the themes of these jokes which go beyond the simple collection and documentation undertaken previously by folklorists and ethnologists. Classification systems As folktales and other types of oral literature became collectables throughout Europe in the 19th century (Brothers Grimm et al.), folklorists and anthropologists of the time needed a system to organise these items. The Aarne–Thompson classification system was first published in 1910 by Antti Aarne, and later expanded by Stith Thompson to become the most renowned classification system for European folktales and other types of oral literature. Its final section addresses anecdotes and jokes, listing traditional humorous tales ordered by their protagonist; "This section of the Index is essentially a classification of the older European jests, or merry tales – humorous stories characterized by short, fairly simple plots. …" Due to its focus on older tale types and obsolete actors (e.g., numbskull), the Aarne–Thompson Index does not provide much help in identifying and classifying the modern joke. A more granular classification system used widely by folklorists and cultural anthropologists is the Thompson Motif Index, which separates tales into their individual story elements. This system enables jokes to be classified according to individual motifs included in the narrative: actors, items and incidents. It does not provide a system to classify the text by more than one element at a time while at the same time making it theoretically possible to classify the same text under multiple motifs. The Thompson Motif Index has spawned further specialised motif indices, each of which focuses on a single aspect of one subset of jokes. A sampling of just a few of these specialised indices have been listed under other motif indices. Here one can select an index for medieval Spanish folk narratives, another index for linguistic verbal jokes, and a third one for sexual humour. To assist the researcher with this increasingly confusing situation, there are also multiple bibliographies of indices as well as a how-to guide on creating your own index. Several difficulties have been identified with these systems of identifying oral narratives according to either tale types or story elements. A first major problem is their hierarchical organisation; one element of the narrative is selected as the major element, while all other parts are arrayed subordinate to this. A second problem with these systems is that the listed motifs are not qualitatively equal; actors, items and incidents are all considered side-by-side. And because incidents will always have at least one actor and usually have an item, most narratives can be ordered under multiple headings. This leads to confusion about both where to order an item and where to find it. A third significant problem is that the "excessive prudery" common in the middle of the 20th century means that obscene, sexual and scatological elements were regularly ignored in many of the indices. The folklorist Robert Georges has summed up the concerns with these existing classification systems: …Yet what the multiplicity and variety of sets and subsets reveal is that folklore [jokes] not only takes many forms, but that it is also multifaceted, with purpose, use, structure, content, style, and function all being relevant and important. Any one or combination of these multiple and varied aspects of a folklore example [such as jokes] might emerge as dominant in a specific situation or for a particular inquiry. It has proven difficult to organise all different elements of a joke into a multi-dimensional classification system which could be of real value in the study and evaluation of this (primarily oral) complex narrative form. The General Theory of Verbal Humour or GTVH, developed by the linguists Victor Raskin and Salvatore Attardo, attempts to do exactly this. This classification system was developed specifically for jokes and later expanded to include longer types of humorous narratives. Six different aspects of the narrative, labelled Knowledge Resources or KRs, can be evaluated largely independently of each other, and then combined into a concatenated classification label. These six KRs of the joke structure include: As development of the GTVH progressed, a hierarchy of the KRs was established to partially restrict the options for lower-level KRs depending on the KRs defined above them. For example, a lightbulb joke (SI) will always be in the form of a riddle (NS). Outside of these restrictions, the KRs can create a multitude of combinations, enabling a researcher to select jokes for analysis which contain only one or two defined KRs. It also allows for an evaluation of the similarity or dissimilarity of jokes depending on the similarity of their labels. "The GTVH presents itself as a mechanism … of generating [or describing] an infinite number of jokes by combining the various values that each parameter can take. … Descriptively, to analyze a joke in the GTVH consists of listing the values of the 6 KRs (with the caveat that TA and LM may be empty)." This classification system provides a functional multi-dimensional label for any joke, and indeed any verbal humour. Joke and humour research Many academic disciplines lay claim to the study of jokes (and other forms of humour) as within their purview. Fortunately, there are enough jokes, good, bad and worse, to go around. The studies of jokes from each of the interested disciplines bring to mind the tale of the blind men and an elephant where the observations, although accurate reflections of their own competent methodological inquiry, frequently fail to grasp the beast in its entirety. This attests to the joke as a traditional narrative form which is indeed complex, concise and complete in and of itself. It requires a "multidisciplinary, interdisciplinary, and cross-disciplinary field of inquiry" to truly appreciate these nuggets of cultural insight.[note 6] Sigmund Freud was one of the first modern scholars to recognise jokes as an important object of investigation. In his 1905 study Jokes and their Relation to the Unconscious Freud describes the social nature of humour and illustrates his text with many examples of contemporary Viennese jokes. His work is particularly noteworthy in this context because Freud distinguishes in his writings between jokes, humour and the comic. These are distinctions which become easily blurred in many subsequent studies where everything funny tends to be gathered under the umbrella term of "humour", making for a much more diffuse discussion. Since the publication of Freud's study, psychologists have continued to explore humour and jokes in their quest to explain, predict and control an individual's "sense of humour". Why do people laugh? Why do people find something funny? Can jokes predict character, or vice versa, can character predict the jokes an individual laughs at? What is a "sense of humour"? A current review of the popular magazine Psychology Today lists over 200 articles discussing various aspects of humour; in psychological jargon, the subject area has become both an emotion to measure and a tool to use in diagnostics and treatment. A new psychological assessment tool, the Values in Action Inventory developed by the American psychologists Christopher Peterson and Martin Seligman includes humour (and playfulness) as one of the core character strengths of an individual. As such, it could be a good predictor of life satisfaction. For psychologists, it would be useful to measure both how much of this strength an individual has and how it can be measurably increased. A 2007 survey of existing tools to measure humour identified more than 60 psychological measurement instruments. These measurement tools use many different approaches to quantify humour along with its related states and traits. There are tools to measure an individual's physical response by their smile; the Facial Action Coding System (FACS) is one of several tools used to identify any one of multiple types of smiles. Or the laugh can be measured to calculate the funniness response of an individual; multiple types of laughter have been identified. It must be stressed here that both smiles and laughter are not always a response to something funny. In trying to develop a measurement tool, most systems use "jokes and cartoons" as their test materials. However, because no two tools use the same jokes, and across languages this would not be feasible, how does one determine that the assessment objects are comparable? Moving on, whom does one ask to rate the sense of humour of an individual? Does one ask the person themselves, an impartial observer, or their family, friends and colleagues? Furthermore, has the current mood of the test subjects been considered; someone with a recent death in the family might not be much prone to laughter. Given the plethora of variants revealed by even a superficial glance at the problem, it becomes evident that these paths of scientific inquiry are mined with problematic pitfalls and questionable solutions. The psychologist Willibald Ruch [de] has been very active in the research of humour. He has collaborated with the linguists Raskin and Attardo on their General Theory of Verbal Humour (GTVH) classification system. Their goal is to empirically test both the six autonomous classification types (KRs) and the hierarchical ordering of these KRs. Advancement in this direction would be a win-win for both fields of study; linguistics would have empirical verification of this multi-dimensional classification system for jokes, and psychology would have a standardised joke classification with which they could develop verifiably comparable measurement tools. "The linguistics of humor has made gigantic strides forward in the last decade and a half and replaced the psychology of humor as the most advanced theoretical approach to the study of this important and universal human faculty." This recent statement by one noted linguist and humour researcher describes, from his perspective, contemporary linguistic humour research. Linguists study words, how words are strung together to build sentences, how sentences create meaning which can be communicated from one individual to another, and how our interaction with each other using words creates discourse. Jokes have been defined above as oral narratives in which words and sentences are engineered to build toward a punchline. The linguist's question is: what exactly makes the punchline funny? This question focuses on how the words used in the punchline create humour, in contrast to the psychologist's concern (see above) with the audience's response to the punchline. The assessment of humour by psychologists "is made from the individual's perspective; e.g. the phenomenon associated with responding to or creating humor and not a description of humor itself." Linguistics, on the other hand, endeavours to provide a precise description of what makes a text funny. Two major new linguistic theories have been developed and tested within the last decades. The first was advanced by Victor Raskin in "Semantic Mechanisms of Humor", published 1985. While being a variant on the more general concepts of the incongruity theory of humour, it is the first theory to identify its approach as exclusively linguistic. The Script-based Semantic Theory of Humour (SSTH) begins by identifying two linguistic conditions which make a text funny. It then goes on to identify the mechanisms involved in creating the punchline. This theory established the semantic/pragmatic foundation of humour as well as the humour competence of speakers.[note 7] Several years later the SSTH was incorporated into a more expansive theory of jokes put forth by Raskin and his colleague Salvatore Attardo. In the General Theory of Verbal Humour, the SSTH was relabelled as a Logical Mechanism (LM) (referring to the mechanism which connects the different linguistic scripts in the joke) and added to five other independent Knowledge Resources (KR). Together these six KRs could now function as a multi-dimensional descriptive label for any piece of humorous text. Linguistics has developed further methodological tools which can be applied to jokes: discourse analysis and conversation analysis of joking. Both of these subspecialties within the field focus on "naturally occurring" language use, i.e. the analysis of real (usually recorded) conversations. One of these studies has already been discussed above, where Harvey Sacks describes in detail the sequential organisation in telling a single joke. Discourse analysis emphasises the entire context of social joking, the social interaction which cradles the words. Folklore and cultural anthropology have perhaps the strongest claims on jokes as belonging to their bailiwick. Jokes remain one of the few remaining forms of traditional folk literature transmitted orally in western cultures. Identified as one of the "simple forms" of oral literature by André Jolles in 1930, they have been collected and studied since there were folklorists and anthropologists abroad in the lands. As a genre they were important enough at the beginning of the 20th century to be included under their own heading in the Aarne–Thompson index first published in 1910: Anecdotes and jokes. Beginning in the 1960s, cultural researchers began to expand their role from collectors and archivists of "folk ideas" to a more active role of interpreters of cultural artefacts. One of the foremost scholars active during this transitional time was the folklorist Alan Dundes. He started asking questions of tradition and transmission with the key observation that "No piece of folklore continues to be transmitted unless it means something, even if neither the speaker nor the audience can articulate what that meaning might be." In the context of jokes, this then becomes the basis for further research. Why is the joke told right now? Only in this expanded perspective is an understanding of its meaning to the participants possible. This questioning resulted in a blossoming of monographs to explore the significance of many joke cycles. What is so funny about absurd nonsense elephant jokes? Why make light of dead babies? In an article on contemporary German jokes about Auschwitz and the Holocaust, Dundes justifies this research: Whether one finds Auschwitz jokes funny or not is not an issue. This material exists and should be recorded. Jokes are always an important barometer of the attitudes of a group. The jokes exist and they obviously must fill some psychic need for those individuals who tell them and those who listen to them. A stimulating generation of new humour theories flourishes like mushrooms in the undergrowth: Elliott Oring's theoretical discussions on "appropriate ambiguity" and Amy Carrell's hypothesis of an "audience-based theory of verbal humor (1993)" to name just a few. In his book Humor and Laughter: An Anthropological Approach, the anthropologist Mahadev Apte presents a solid case for his own academic perspective. "Two axioms underlie my discussion, namely, that humor is by and large culture based and that humor can be a major conceptual and methodological tool for gaining insights into cultural systems." Apte goes on to call for legitimising the field of humour research as "humorology"; this would be a field of study incorporating an interdisciplinary character of humour studies. While the label "humorology" has yet to become a household word, great strides are being made in the international recognition of this interdisciplinary field of research. The International Society for Humor Studies was founded in 1989 with the stated purpose to "promote, stimulate and encourage the interdisciplinary study of humour; to support and cooperate with local, national, and international organizations having similar purposes; to organize and arrange meetings; and to issue and encourage publications concerning the purpose of the society". It also publishes Humor: International Journal of Humor Research and holds yearly conferences to promote and inform its speciality. In 1872, Charles Darwin published one of the first "comprehensive and in many ways remarkably accurate description of laughter in terms of respiration, vocalization, facial action and gesture and posture" (Laughter) in The Expression of the Emotions in Man and Animals. In this early study Darwin raises further questions about who laughs and why they laugh; the myriad responses since then illustrate the complexities of this behaviour. To understand laughter in humans and other primates, the science of gelotology (from the Greek gelos, meaning laughter) has been established; it is the study of laughter and its effects on the body from both a psychological and physiological perspective. While jokes can provoke laughter, laughter cannot be used as a one-to-one marker of jokes because there are multiple stimuli to laughter, humour being just one of them. The other six causes of laughter listed are social context, ignorance, anxiety, derision, acting apology, and tickling. As such, the study of laughter is a secondary albeit entertaining perspective in an understanding of jokes. Computational humour is a new field of study which uses computers to model humour; it bridges the disciplines of computational linguistics and artificial intelligence. A primary ambition of this field is to develop computer programs which can both generate a joke and recognise a text snippet as a joke. Early programming attempts have dealt almost exclusively with punning because this lends itself to simple straightforward rules. These primitive programs display no intelligence; instead, they work off a template with a finite set of pre-defined punning options upon which to build. More sophisticated computer joke programs have yet to be developed. Based on our understanding of the SSTH / GTVH humour theories, it is easy to see why. The linguistic scripts (a.k.a. frames) referenced in these theories include, for any given word, a "large chunk of semantic information surrounding the word and evoked by it [...] a cognitive structure internalized by the native speaker". These scripts extend much further than the lexical definition of a word; they contain the speaker's complete knowledge of the concept as it exists in his world. As insentient machines, computers lack the encyclopaedic scripts which humans gain through life experience. They also lack the ability to gather the experiences needed to build wide-ranging semantic scripts and understand language in a broader context, a context that any child picks up in daily interaction with his environment. Further development in this field must wait until computational linguists have succeeded in programming a computer with an ontological semantic natural language processing system. It is only "the most complex linguistic structures [which] can serve any formal and/or computational treatment of humor well". Toy systems (i.e. dummy punning programs) are completely inadequate to the task. Despite the fact that the field of computational humour is small and underdeveloped, it is encouraging to note the many interdisciplinary efforts which are currently underway. See also Notes References Further reading |
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[SOURCE: https://en.wikipedia.org/wiki/Minecraft#cite_ref-credits_223-0] | [TOKENS: 12858] |
Contents Minecraft Minecraft is a sandbox game developed and published by Mojang Studios. Following its initial public alpha release in 2009, it was formally released in 2011 for personal computers. The game has since been ported to numerous platforms, including mobile devices and various video game consoles. In Minecraft, players explore a procedurally generated world with virtually infinite terrain made up of voxels (cubes). They can discover and extract raw materials, craft tools and items, build structures, fight hostile mobs, and cooperate with or compete against other players in multiplayer. The game's large community offers a wide variety of user-generated content, such as modifications, servers, player skins, texture packs, and custom maps, which add new game mechanics and possibilities. Originally created by Markus "Notch" Persson using the Java programming language, Jens "Jeb" Bergensten was handed control over the game's development following its full release. In 2014, Mojang and the Minecraft intellectual property were purchased by Microsoft for US$2.5 billion; Xbox Game Studios hold the publishing rights for the Bedrock Edition, the unified cross-platform version which evolved from the Pocket Edition codebase[i] and replaced the legacy console versions. Bedrock is updated concurrently with Mojang's original Java Edition, although with numerous, generally small, differences. Minecraft is the best-selling video game in history with over 350 million copies sold. It has received critical acclaim, winning several awards and being cited as one of the greatest video games of all time. Social media, parodies, adaptations, merchandise, and the annual Minecon conventions have played prominent roles in popularizing it. The wider Minecraft franchise includes several spin-off games, such as Minecraft: Story Mode, Minecraft Dungeons, and Minecraft Legends. A film adaptation, titled A Minecraft Movie, was released in 2025 and became the second highest-grossing video game film of all time. Gameplay Minecraft is a 3D sandbox video game that has no required goals to accomplish, giving players a large amount of freedom in choosing how to play the game. The game features an optional achievement system. Gameplay is in the first-person perspective by default, but players have the option of third-person perspectives. The game world is composed of rough 3D objects—mainly cubes, referred to as blocks—representing various materials, such as dirt, stone, ores, tree trunks, water, and lava. The core gameplay revolves around picking up and placing these objects. These blocks are arranged in a voxel grid, while players can move freely around the world. Players can break, or mine, blocks and then place them elsewhere, enabling them to build things. Very few blocks are affected by gravity, instead maintaining their voxel position in the air. Players can also craft a wide variety of items, such as armor, which mitigates damage from attacks; weapons (such as swords or bows and arrows), which allow monsters and animals to be killed more easily; and tools (such as pickaxes or shovels), which break certain types of blocks more quickly. Some items have multiple tiers depending on the material used to craft them, with higher-tier items being more effective and durable. They may also freely craft helpful blocks—such as furnaces which can cook food and smelt ores, and torches that produce light—or exchange items with villagers (NPC) through trading emeralds for different goods and vice versa. The game has an inventory system, allowing players to carry a limited number of items. The in-game time system follows a day and night cycle, with one full cycle lasting for 20 real-time minutes. The game also contains a material called redstone, which can be used to make primitive mechanical devices, electrical circuits, and logic gates, allowing for the construction of many complex systems. New players are given a randomly selected default character skin out of nine possibilities, including Steve or Alex, but are able to create and upload their own skins. Players encounter various mobs (short for mobile entities) including animals, villagers, and hostile creatures. Passive mobs, such as cows, pigs, and chickens, spawn during the daytime and can be hunted for food and crafting materials, while hostile mobs—including large spiders, witches, skeletons, and zombies—spawn during nighttime or in dark places such as caves. Some hostile mobs, such as zombies and skeletons, burn under the sun if they have no headgear and are not standing in water. Other creatures unique to Minecraft include the creeper (an exploding creature that sneaks up on the player) and the enderman (a creature with the ability to teleport as well as pick up and place blocks). There are also variants of mobs that spawn in different conditions; for example, zombies have husk and drowned variants that spawn in deserts and oceans, respectively. The Minecraft environment is procedurally generated as players explore it using a map seed that is randomly chosen at the time of world creation (or manually specified by the player). Divided into biomes representing different environments with unique resources and structures, worlds are designed to be effectively infinite in traditional gameplay, though technical limits on the player have existed throughout development, both intentionally and not. Implementation of horizontally infinite generation initially resulted in a glitch termed the "Far Lands" at over 12 million blocks away from the world center, where terrain generated as wall-like, fissured patterns. The Far Lands and associated glitches were considered the effective edge of the world until they were resolved, with the current horizontal limit instead being a special impassable barrier called the world border, located 30 million blocks away. Vertical space is comparatively limited, with an unbreakable bedrock layer at the bottom and a building limit several hundred blocks into the sky. Minecraft features three independent dimensions accessible through portals and providing alternate game environments. The Overworld is the starting dimension and represents the real world, with a terrestrial surface setting including plains, mountains, forests, oceans, caves, and small sources of lava. The Nether is a hell-like underworld dimension accessed via an obsidian portal and composed mainly of lava. Mobs that populate the Nether include shrieking, fireball-shooting ghasts, alongside anthropomorphic pigs called piglins and their zombified counterparts. Piglins in particular have a bartering system, where players can give them gold ingots and receive items in return. Structures known as Nether Fortresses generate in the Nether, containing mobs such as wither skeletons and blazes, which can drop blaze rods needed to access the End dimension. The player can also choose to build an optional boss mob known as the Wither, using skulls obtained from wither skeletons and soul sand. The End can be reached through an end portal, consisting of twelve end portal frames. End portals are found in underground structures in the Overworld known as strongholds. To find strongholds, players must craft eyes of ender using an ender pearl and blaze powder. Eyes of ender can then be thrown, traveling in the direction of the stronghold. Once the player reaches the stronghold, they can place eyes of ender into each portal frame to activate the end portal. The dimension consists of islands floating in a dark, bottomless void. A boss enemy called the Ender Dragon guards the largest, central island. Killing the dragon opens access to an exit portal, which, when entered, cues the game's ending credits and the End Poem, a roughly 1,500-word work written by Irish novelist Julian Gough, which takes about nine minutes to scroll past, is the game's only narrative text, and the only text of significant length directed at the player.: 10–12 At the conclusion of the credits, the player is teleported back to their respawn point and may continue the game indefinitely. In Survival mode, players have to gather natural resources such as wood and stone found in the environment in order to craft certain blocks and items. Depending on the difficulty, monsters spawn in darker areas outside a certain radius of the character, requiring players to build a shelter in order to survive at night. The mode also has a health bar which is depleted by attacks from mobs, falls, drowning, falling into lava, suffocation, starvation, and other events. Players also have a hunger bar, which must be periodically refilled by eating food in-game unless the player is playing on peaceful difficulty. If the hunger bar is empty, the player starves. Health replenishes when players have a full hunger bar or continuously on peaceful. Upon losing all health, players die. The items in the players' inventories are dropped unless the game is reconfigured not to do so. Players then re-spawn at their spawn point, which by default is where players first spawn in the game and can be changed by sleeping in a bed or using a respawn anchor. Dropped items can be recovered if players can reach them before they despawn after 5 minutes. Players may acquire experience points (commonly referred to as "xp" or "exp") by killing mobs and other players, mining, smelting ores, animal breeding, and cooking food. Experience can then be spent on enchanting tools, armor and weapons. Enchanted items are generally more powerful, last longer, or have other special effects. The game features two more game modes based on Survival, known as Hardcore mode and Adventure mode. Hardcore mode plays identically to Survival mode, but with the game's difficulty setting locked to "Hard" and with permadeath, forcing them to delete the world or explore it as a spectator after dying. Adventure mode was added to the game in a post-launch update, and prevents the player from directly modifying the game's world. It was designed primarily for use in custom maps, allowing map designers to let players experience it as intended. In Creative mode, players have access to an infinite number of all resources and items in the game through the inventory menu and can place or mine them instantly. Players can toggle the ability to fly freely around the game world at will, and their characters usually do not take any damage nor are affected by hunger. The game mode helps players focus on building and creating projects of any size without disturbance. Multiplayer in Minecraft enables multiple players to interact and communicate with each other on a single world. It is available through direct game-to-game multiplayer, local area network (LAN) play, local split screen (console-only), and servers (player-hosted and business-hosted). Players can run their own server by making a realm, using a host provider, hosting one themselves or connect directly to another player's game via Xbox Live, PlayStation Network or Nintendo Switch Online. Single-player worlds have LAN support, allowing players to join a world on locally interconnected computers without a server setup. Minecraft multiplayer servers are guided by server operators, who have access to server commands such as setting the time of day and teleporting players. Operators can also set up restrictions concerning which usernames or IP addresses are allowed or disallowed to enter the server. Multiplayer servers have a wide range of activities, with some servers having their own unique rules and customs. The largest and most popular server is Hypixel, which has been visited by over 14 million unique players. Player versus player combat (PvP) can be enabled to allow fighting between players. In 2013, Mojang announced Minecraft Realms, a server hosting service intended to enable players to run server multiplayer games easily and safely without having to set up their own. Unlike a standard server, only invited players can join Realms servers, and these servers do not use server addresses. Minecraft: Java Edition Realms server owners can invite up to twenty people to play on their server, with up to ten players online at a time. Minecraft Realms server owners can invite up to 3,000 people to play on their server, with up to ten players online at one time. The Minecraft: Java Edition Realms servers do not support user-made plugins, but players can play custom Minecraft maps. Minecraft Bedrock Realms servers support user-made add-ons, resource packs, behavior packs, and custom Minecraft maps. At Electronic Entertainment Expo 2016, support for cross-platform play between Windows 10, iOS, and Android platforms was added through Realms starting in June 2016, with Xbox One and Nintendo Switch support to come later in 2017, and support for virtual reality devices. On 31 July 2017, Mojang released the beta version of the update allowing cross-platform play. Nintendo Switch support for Realms was released in July 2018. The modding community consists of fans, users and third-party programmers. Using a variety of application program interfaces that have arisen over time, they have produced a wide variety of downloadable content for Minecraft, such as modifications, texture packs and custom maps. Modifications of the Minecraft code, called mods, add a variety of gameplay changes, ranging from new blocks, items, and mobs to entire arrays of mechanisms. The modding community is responsible for a substantial supply of mods from ones that enhance gameplay, such as mini-maps, waypoints, and durability counters, to ones that add to the game elements from other video games and media. While a variety of mod frameworks were independently developed by reverse engineering the code, Mojang has also enhanced vanilla Minecraft with official frameworks for modification, allowing the production of community-created resource packs, which alter certain game elements including textures and sounds. Players can also create their own "maps" (custom world save files) that often contain specific rules, challenges, puzzles and quests, and share them for others to play. Mojang added an adventure mode in August 2012 and "command blocks" in October 2012, which were created specially for custom maps in Java Edition. Data packs, introduced in version 1.13 of the Java Edition, allow further customization, including the ability to add new achievements, dimensions, functions, loot tables, predicates, recipes, structures, tags, and world generation. The Xbox 360 Edition supported downloadable content, which was available to purchase via the Xbox Games Store; these content packs usually contained additional character skins. It later received support for texture packs in its twelfth title update while introducing "mash-up packs", which combined texture packs with skin packs and changes to the game's sounds, music and user interface. The first mash-up pack (and by extension, the first texture pack) for the Xbox 360 Edition was released on 4 September 2013, and was themed after the Mass Effect franchise. Unlike Java Edition, however, the Xbox 360 Edition did not support player-made mods or custom maps. A cross-promotional resource pack based on the Super Mario franchise by Nintendo was released exclusively for the Wii U Edition worldwide on 17 May 2016, and later bundled free with the Nintendo Switch Edition at launch. Another based on Fallout was released on consoles that December, and for Windows and Mobile in April 2017. In April 2018, malware was discovered in several downloadable user-made Minecraft skins for use with the Java Edition of the game. Avast stated that nearly 50,000 accounts were infected, and when activated, the malware would attempt to reformat the user's hard drive. Mojang promptly patched the issue, and released a statement stating that "the code would not be run or read by the game itself", and would run only when the image containing the skin itself was opened. In June 2017, Mojang released the "1.1 Discovery Update" to the Pocket Edition of the game, which later became the Bedrock Edition. The update introduced the "Marketplace", a catalogue of purchasable user-generated content intended to give Minecraft creators "another way to make a living from the game". Various skins, maps, texture packs and add-ons from different creators can be bought with "Minecoins", a digital currency that is purchased with real money. Additionally, users can access specific content with a subscription service titled "Marketplace Pass". Alongside content from independent creators, the Marketplace also houses items published by Mojang and Microsoft themselves, as well as official collaborations between Minecraft and other intellectual properties. By 2022, the Marketplace had over 1.7 billion content downloads, generating over $500 million in revenue. Development Before creating Minecraft, Markus "Notch" Persson was a game developer at King, where he worked until March 2009. At King, he primarily developed browser games and learned several programming languages. During his free time, he prototyped his own games, often drawing inspiration from other titles, and was an active participant on the TIGSource forums for independent developers. One such project was "RubyDung", a base-building game inspired by Dwarf Fortress, but with an isometric, three-dimensional perspective similar to RollerCoaster Tycoon. Among the features in RubyDung that he explored was a first-person view similar to Dungeon Keeper, though he ultimately discarded this idea, feeling the graphics were too pixelated at the time. Around March 2009, Persson left King and joined jAlbum, while continuing to work on his prototypes. Infiniminer, a block-based open-ended mining game first released in April 2009, inspired Persson's vision for RubyDung's future direction. Infiniminer heavily influenced the visual style of gameplay, including bringing back the first-person mode, the "blocky" visual style and the block-building fundamentals. However, unlike Infiniminer, Persson wanted Minecraft to have RPG elements. The first public alpha build of Minecraft was released on 17 May 2009 on TIGSource. Over the years, Persson regularly released test builds that added new features, including tools, mobs, and entire new dimensions. In 2011, partly due to the game's rising popularity, Persson decided to release a full 1.0 version—a second part of the "Adventure Update"—on 18 November 2011. Shortly after, Persson stepped down from development, handing the project's lead to Jens "Jeb" Bergensten. On 15 September 2014, Microsoft, the developer behind the Microsoft Windows operating system and Xbox video game console, announced a $2.5 billion acquisition of Mojang, which included the Minecraft intellectual property. Persson had suggested the deal on Twitter, asking a corporation to buy his stake in the game after receiving criticism for enforcing terms in the game's end-user license agreement (EULA), which had been in place for the past three years. According to Persson, Mojang CEO Carl Manneh received a call from a Microsoft executive shortly after the tweet, asking if Persson was serious about a deal. Mojang was also approached by other companies including Activision Blizzard and Electronic Arts. The deal with Microsoft was arbitrated on 6 November 2014 and led to Persson becoming one of Forbes' "World's Billionaires". After 2014, Minecraft's primary versions received usually annual major updates—free to players who have purchased the game— each primarily centered around a specific theme. For instance, version 1.13, the Update Aquatic, focused on ocean-related features, while version 1.16, the Nether Update, introduced significant changes to the Nether dimension. However, in late 2024, Mojang announced a shift in their update strategy; rather than releasing large updates annually, they opted for a more frequent release schedule with smaller, incremental updates, stating, "We know that you want new Minecraft content more often." The Bedrock Edition has also received regular updates, now matching the themes of the Java Edition updates. Other versions of the game, such as various console editions and the Pocket Edition, were either merged into Bedrock or discontinued and have not received further updates. On 7 May 2019, coinciding with Minecraft's 10th anniversary, a JavaScript recreation of an old 2009 Java Edition build named Minecraft Classic was made available to play online for free. On 16 April 2020, a Bedrock Edition-exclusive beta version of Minecraft, called Minecraft RTX, was released by Nvidia. It introduced physically-based rendering, real-time path tracing, and DLSS for RTX-enabled GPUs. The public release was made available on 8 December 2020. Path tracing can only be enabled in supported worlds, which can be downloaded for free via the in-game Minecraft Marketplace, with a texture pack from Nvidia's website, or with compatible third-party texture packs. It cannot be enabled by default with any texture pack on any world. Initially, Minecraft RTX was affected by many bugs, display errors, and instability issues. On 22 March 2025, a new visual mode called Vibrant Visuals, an optional graphical overhaul similar to Minecraft RTX, was announced. It promises modern rendering features—such as dynamic shadows, screen space reflections, volumetric fog, and bloom—without the need of RTX-capable hardware. Vibrant Visuals was released as a part of the Chase the Skies update on 17 June 2025 for Bedrock Edition and is planned to release on Java Edition at a later date. Development began for the original edition of Minecraft—then known as Cave Game, and now known as the Java Edition—in May 2009,[k] and ended on 13 May, when Persson released a test video on YouTube of an early version of the game, dubbed the "Cave game tech test" or the "Cave game tech demo". The game was named Minecraft: Order of the Stone the next day, after a suggestion made by a player. "Order of the Stone" came from the webcomic The Order of the Stick, and "Minecraft" was chosen "because it's a good name". The title was later shortened to just Minecraft, omitting the subtitle. Persson completed the game's base programming over a weekend in May 2009, and private testing began on TigIRC on 16 May. The first public release followed on 17 May 2009 as a developmental version shared on the TIGSource forums. Based on feedback from forum users, Persson continued updating the game. This initial public build later became known as Classic. Further developmental phases—dubbed Survival Test, Indev, and Infdev—were released throughout 2009 and 2010. The first major update, known as Alpha, was released on 30 June 2010. At the time, Persson was still working a day job at jAlbum but later resigned to focus on Minecraft full-time as sales of the alpha version surged. Updates were distributed automatically, introducing new blocks, items, mobs, and changes to game mechanics such as water flow. With revenue generated from the game, Persson founded Mojang, a video game studio, alongside former colleagues Jakob Porser and Carl Manneh. On 11 December 2010, Persson announced that Minecraft would enter its beta phase on 20 December. He assured players that bug fixes and all pre-release updates would remain free. As development progressed, Mojang expanded, hiring additional employees to work on the project. The game officially exited beta and launched in full on 18 November 2011. On 1 December 2011, Jens "Jeb" Bergensten took full creative control over Minecraft, replacing Persson as lead designer. On 28 February 2012, Mojang announced the hiring of the developers behind Bukkit, a popular developer API for Minecraft servers, to improve Minecraft's support of server modifications. This move included Mojang taking apparent ownership of the CraftBukkit server mod, though this apparent acquisition later became controversial, and its legitimacy was questioned due to CraftBukkit's open-source nature and licensing under the GNU General Public License and Lesser General Public License. In August 2011, Minecraft: Pocket Edition was released as an early alpha for the Xperia Play via the Android Market, later expanding to other Android devices on 8 October 2011. The iOS version followed on 17 November 2011. A port was made available for Windows Phones shortly after Microsoft acquired Mojang. Unlike Java Edition, Pocket Edition initially focused on Minecraft's creative building and basic survival elements but lacked many features of the PC version. Bergensten confirmed on Twitter that the Pocket Edition was written in C++ rather than Java, as iOS does not support Java. On 10 December 2014, a port of Pocket Edition was released for Windows Phone 8.1. In July 2015, a port of the Pocket Edition to Windows 10 was released as the Windows 10 Edition, with full crossplay to other Pocket versions. In January 2017, Microsoft announced that it would no longer maintain the Windows Phone versions of Pocket Edition. On 20 September 2017, with the "Better Together Update", the Pocket Edition was ported to the Xbox One, and was renamed to the Bedrock Edition. The console versions of Minecraft debuted with the Xbox 360 edition, developed by 4J Studios and released on 9 May 2012. Announced as part of the Xbox Live Arcade NEXT promotion, this version introduced a redesigned crafting system, a new control interface, in-game tutorials, split-screen multiplayer, and online play via Xbox Live. Unlike the PC version, its worlds were finite, bordered by invisible walls. Initially, the Xbox 360 version resembled outdated PC versions but received updates to bring it closer to Java Edition before eventually being discontinued. The Xbox One version launched on 5 September 2014, featuring larger worlds and support for more players. Minecraft expanded to PlayStation platforms with PlayStation 3 and PlayStation 4 editions released on 17 December 2013 and 4 September 2014, respectively. Originally planned as a PS4 launch title, it was delayed before its eventual release. A PlayStation Vita version followed in October 2014. Like the Xbox versions, the PlayStation editions were developed by 4J Studios. Nintendo platforms received Minecraft: Wii U Edition on 17 December 2015, with a physical release in North America on 17 June 2016 and in Europe on 30 June. The Nintendo Switch version launched via the eShop on 11 May 2017. During a Nintendo Direct presentation on 13 September 2017, Nintendo announced that Minecraft: New Nintendo 3DS Edition, based on the Pocket Edition, would be available for download immediately after the livestream, and a physical copy available on a later date. The game is compatible only with the New Nintendo 3DS or New Nintendo 2DS XL systems and does not work with the original 3DS or 2DS systems. On 20 September 2017, the Better Together Update introduced Bedrock Edition across Xbox One, Windows 10, VR, and mobile platforms, enabling cross-play between these versions. Bedrock Edition later expanded to Nintendo Switch and PlayStation 4, with the latter receiving the update in December 2019, allowing cross-platform play for users with a free Xbox Live account. The Bedrock Edition released a native version for PlayStation 5 on 22 October 2024, while the Xbox Series X/S version launched on 17 June 2025. On 18 December 2018, the PlayStation 3, PlayStation Vita, Xbox 360, and Wii U versions of Minecraft received their final update and would later become known as "Legacy Console Editions". On 15 January 2019, the New Nintendo 3DS version of Minecraft received its final update, effectively becoming discontinued as well. An educational version of Minecraft, designed for use in schools, launched on 1 November 2016. It is available on Android, ChromeOS, iPadOS, iOS, MacOS, and Windows. On 20 August 2018, Mojang announced that it would bring Education Edition to iPadOS in Autumn 2018. It was released to the App Store on 6 September 2018. On 27 March 2019, it was announced that it would be operated by JD.com in China. On 26 June 2020, a public beta for the Education Edition was made available to Google Play Store compatible Chromebooks. The full game was released to the Google Play Store for Chromebooks on 7 August 2020. On 20 May 2016, China Edition (also known as My World) was announced as a localized edition for China, where it was released under a licensing agreement between NetEase and Mojang. The PC edition was released for public testing on 8 August 2017. The iOS version was released on 15 September 2017, and the Android version was released on 12 October 2017. The PC edition is based on the original Java Edition, while the iOS and Android mobile versions are based on the Bedrock Edition. The edition is free-to-play and had over 700 million registered accounts by September 2023. This version of Bedrock Edition is exclusive to Microsoft's Windows 10 and Windows 11 operating systems. The beta release for Windows 10 launched on the Windows Store on 29 July 2015. After nearly a year and a half in beta, Microsoft fully released the version on 19 December 2016. Called the "Ender Update", this release implemented new features to this version of Minecraft like world templates and add-on packs. On 7 June 2022, the Java and Bedrock Editions of Minecraft were merged into a single bundle for purchase on Windows; those who owned one version would automatically gain access to the other version. Both game versions would otherwise remain separate. Around 2011, prior to Minecraft's full release, Mojang collaborated with The Lego Group to create a Lego brick-based Minecraft game called Brickcraft. This would have modified the base Minecraft game to use Lego bricks, which meant adapting the basic 1×1 block to account for larger pieces typically used in Lego sets. Persson worked on an early version called "Project Rex Kwon Do", named after the character of the same name from the film Napoleon Dynamite. Although Lego approved the project and Mojang assigned two developers for six months, it was canceled due to the Lego Group's demands, according to Mojang's Daniel Kaplan. Lego considered buying Mojang to complete the game, but when Microsoft offered over $2 billion for the company, Lego stepped back, unsure of Minecraft's potential. On 26 June 2025, a build of Brickcraft dated 28 June 2012 was published on a community archive website Omniarchive. Initially, Markus Persson planned to support the Oculus Rift with a Minecraft port. However, after Facebook acquired Oculus in 2013, he abruptly canceled the plans, stating, "Facebook creeps me out." In 2016, a community-made mod, Minecraft VR, added VR support for Java Edition, followed by Vivecraft for HTC Vive. Later that year, Microsoft introduced official Oculus Rift support for Windows 10 Edition, leading to the discontinuation of the Minecraft VR mod due to trademark complaints. Vivecraft was endorsed by Minecraft VR contributors for its Rift support. Also available is a Gear VR version, titled Minecraft: Gear VR Edition. Windows Mixed Reality support was added in 2017. On 7 September 2020, Mojang Studios announced that the PlayStation 4 Bedrock version would receive PlayStation VR support later that month. In September 2024, the Minecraft team announced they would no longer support PlayStation VR, which received its final update in March 2025. Music and sound design Minecraft's music and sound effects were produced by German musician Daniel Rosenfeld, better known as C418. To create the sound effects for the game, Rosenfeld made extensive use of Foley techniques. On learning the processes for the game, he remarked, "Foley's an interesting thing, and I had to learn its subtleties. Early on, I wasn't that knowledgeable about it. It's a whole trial-and-error process. You just make a sound and eventually you go, 'Oh my God, that's it! Get the microphone!' There's no set way of doing anything at all." He reminisced on creating the in-game sound for grass blocks, stating "It turns out that to make grass sounds you don't actually walk on grass and record it, because grass sounds like nothing. What you want to do is get a VHS, break it apart, and just lightly touch the tape." According to Rosenfeld, his favorite sound to design for the game was the hisses of spiders. He elaborates, "I like the spiders. Recording that was a whole day of me researching what a spider sounds like. Turns out, there are spiders that make little screeching sounds, so I think I got this recording of a fire hose, put it in a sampler, and just pitched it around until it sounded like a weird spider was talking to you." Many of the sound design decisions by Rosenfeld were done accidentally or spontaneously. The creeper notably lacks any specific noises apart from a loud fuse-like sound when about to explode; Rosenfeld later recalled "That was just a complete accident by Markus and me [sic]. We just put in a placeholder sound of burning a matchstick. It seemed to work hilariously well, so we kept it." On other sounds, such as those of the zombie, Rosenfeld remarked, "I actually never wanted the zombies so scary. I intentionally made them sound comical. It's nice to hear that they work so well [...]." Rosenfeld remarked that the sound engine was "terrible" to work with, remembering "If you had two song files at once, it [the game engine] would actually crash. There were so many more weird glitches like that the guys never really fixed because they were too busy with the actual game and not the sound engine." The background music in Minecraft consists of instrumental ambient music. To compose the music of Minecraft, Rosenfeld used the package from Ableton Live, along with several additional plug-ins. Speaking on them, Rosenfeld said "They can be pretty much everything from an effect to an entire orchestra. Additionally, I've got some synthesizers that are attached to the computer. Like a Moog Voyager, Dave Smith Prophet 08 and a Virus TI." On 4 March 2011, Rosenfeld released a soundtrack titled Minecraft – Volume Alpha; it includes most of the tracks featured in Minecraft, as well as other music not featured in the game. Kirk Hamilton of Kotaku chose the music in Minecraft as one of the best video game soundtracks of 2011. On 9 November 2013, Rosenfeld released the second official soundtrack, titled Minecraft – Volume Beta, which included the music that was added in a 2013 "Music Update" for the game. A physical release of Volume Alpha, consisting of CDs, black vinyl, and limited-edition transparent green vinyl LPs, was issued by indie electronic label Ghostly International on 21 August 2015. On 14 August 2020, Ghostly released Volume Beta on CD and vinyl, with alternate color LPs and lenticular cover pressings released in limited quantities. The final update Rosenfeld worked on was 2018's 1.13 Update Aquatic. His music remained the only music in the game until 2020's "Nether Update", introducing pieces from Lena Raine. Since then, other composers have made contributions, including Kumi Tanioka, Samuel Åberg, Aaron Cherof, and Amos Roddy, with Raine remaining as the new primary composer. Ownership of all music besides Rosenfeld's independently released albums has been retained by Microsoft, with their label publishing all of the other artists' releases. Gareth Coker also composed some of the music for the game's mini games from the Legacy Console editions. Rosenfeld had stated his intent to create a third album of music for the game in a 2015 interview with Fact, and confirmed its existence in a 2017 tweet, stating that his work on the record as of then had tallied up to be longer than the previous two albums combined, which in total clocks in at over 3 hours and 18 minutes. However, due to licensing issues with Microsoft, the third volume has since not seen release. On 8 January 2021, Rosenfeld was asked in an interview with Anthony Fantano whether or not there was still a third volume of his music intended for release. Rosenfeld responded, saying, "I have something—I consider it finished—but things have become complicated, especially as Minecraft is now a big property, so I don't know." Reception Minecraft has received critical acclaim, with praise for the creative freedom it grants players in-game, as well as the ease of enabling emergent gameplay. Critics have expressed enjoyment in Minecraft's complex crafting system, commenting that it is an important aspect of the game's open-ended gameplay. Most publications were impressed by the game's "blocky" graphics, with IGN describing them as "instantly memorable". Reviewers also liked the game's adventure elements, noting that the game creates a good balance between exploring and building. The game's multiplayer feature has been generally received favorably, with IGN commenting that "adventuring is always better with friends". Jaz McDougall of PC Gamer said Minecraft is "intuitively interesting and contagiously fun, with an unparalleled scope for creativity and memorable experiences". It has been regarded as having introduced millions of children to the digital world, insofar as its basic game mechanics are logically analogous to computer commands. IGN was disappointed about the troublesome steps needed to set up multiplayer servers, calling it a "hassle". Critics also said that visual glitches occur periodically. Despite its release out of beta in 2011, GameSpot said the game had an "unfinished feel", adding that some game elements seem "incomplete or thrown together in haste". A review of the alpha version, by Scott Munro of the Daily Record, called it "already something special" and urged readers to buy it. Jim Rossignol of Rock Paper Shotgun also recommended the alpha of the game, calling it "a kind of generative 8-bit Lego Stalker". On 17 September 2010, gaming webcomic Penny Arcade began a series of comics and news posts about the addictiveness of the game. The Xbox 360 version was generally received positively by critics, but did not receive as much praise as the PC version. Although reviewers were disappointed by the lack of features such as mod support and content from the PC version, they acclaimed the port's addition of a tutorial and in-game tips and crafting recipes, saying that they make the game more user-friendly. The Xbox One Edition was one of the best received ports, being praised for its relatively large worlds. The PlayStation 3 Edition also received generally favorable reviews, being compared to the Xbox 360 Edition and praised for its well-adapted controls. The PlayStation 4 edition was the best received port to date, being praised for having 36 times larger worlds than the PlayStation 3 edition and described as nearly identical to the Xbox One edition. The PlayStation Vita Edition received generally positive reviews from critics but was noted for its technical limitations. The Wii U version received generally positive reviews from critics but was noted for a lack of GamePad integration. The 3DS version received mixed reviews, being criticized for its high price, technical issues, and lack of cross-platform play. The Nintendo Switch Edition received fairly positive reviews from critics, being praised, like other modern ports, for its relatively larger worlds. Minecraft: Pocket Edition initially received mixed reviews from critics. Although reviewers appreciated the game's intuitive controls, they were disappointed by the lack of content. The inability to collect resources and craft items, as well as the limited types of blocks and lack of hostile mobs, were especially criticized. After updates added more content, Pocket Edition started receiving more positive reviews. Reviewers complimented the controls and the graphics, but still noted a lack of content. Minecraft surpassed over a million purchases less than a month after entering its beta phase in early 2011. At the same time, the game had no publisher backing and has never been commercially advertised except through word of mouth, and various unpaid references in popular media such as the Penny Arcade webcomic. By April 2011, Persson estimated that Minecraft had made €23 million (US$33 million) in revenue, with 800,000 sales of the alpha version of the game, and over 1 million sales of the beta version. In November 2011, prior to the game's full release, Minecraft beta surpassed 16 million registered users and 4 million purchases. By March 2012, Minecraft had become the 6th best-selling PC game of all time. As of 10 October 2014[update], the game had sold 17 million copies on PC, becoming the best-selling PC game of all time. On 25 February 2014, the game reached 100 million registered users. By May 2019, 180 million copies had been sold across all platforms, making it the single best-selling video game of all time. The free-to-play Minecraft China version had over 700 million registered accounts by September 2023. By 2023, the game had sold over 300 million copies. As of April 2025, Minecraft has sold over 350 million copies. The Xbox 360 version of Minecraft became profitable within the first day of the game's release in 2012, when the game broke the Xbox Live sales records with 400,000 players online. Within a week of being on the Xbox Live Marketplace, Minecraft sold a million copies. GameSpot announced in December 2012 that Minecraft sold over 4.48 million copies since the game debuted on Xbox Live Arcade in May 2012. In 2012, Minecraft was the most purchased title on Xbox Live Arcade; it was also the fourth most played title on Xbox Live based on average unique users per day. As of 4 April 2014[update], the Xbox 360 version has sold 12 million copies. In addition, Minecraft: Pocket Edition has reached a figure of 21 million in sales. The PlayStation 3 Edition sold one million copies in five weeks. The release of the game's PlayStation Vita version boosted Minecraft sales by 79%, outselling both PS3 and PS4 debut releases and becoming the largest Minecraft launch on a PlayStation console. The PS Vita version sold 100,000 digital copies in Japan within the first two months of release, according to an announcement by SCE Japan Asia. By January 2015, 500,000 digital copies of Minecraft were sold in Japan across all PlayStation platforms, with a surge in primary school children purchasing the PS Vita version. As of 2022, the Vita version has sold over 1.65 million physical copies in Japan, making it the best-selling Vita game in the country. Minecraft helped improve Microsoft's total first-party revenue by $63 million for the 2015 second quarter. The game, including all of its versions, had over 112 million monthly active players by September 2019. On its 11th anniversary in May 2020, the company announced that Minecraft had reached over 200 million copies sold across platforms with over 126 million monthly active players. By April 2021, the number of active monthly users had climbed to 140 million. In July 2010, PC Gamer listed Minecraft as the fourth-best game to play at work. In December of that year, Good Game selected Minecraft as their choice for Best Downloadable Game of 2010, Gamasutra named it the eighth best game of the year as well as the eighth best indie game of the year, and Rock, Paper, Shotgun named it the "game of the year". Indie DB awarded the game the 2010 Indie of the Year award as chosen by voters, in addition to two out of five Editor's Choice awards for Most Innovative and Best Singleplayer Indie. It was also awarded Game of the Year by PC Gamer UK. The game was nominated for the Seumas McNally Grand Prize, Technical Excellence, and Excellence in Design awards at the March 2011 Independent Games Festival and won the Grand Prize and the community-voted Audience Award. At Game Developers Choice Awards 2011, Minecraft won awards in the categories for Best Debut Game, Best Downloadable Game and Innovation Award, winning every award for which it was nominated. It also won GameCity's video game arts award. On 5 May 2011, Minecraft was selected as one of the 80 games that would be displayed at the Smithsonian American Art Museum as part of The Art of Video Games exhibit that opened on 16 March 2012. At the 2011 Spike Video Game Awards, Minecraft won the award for Best Independent Game and was nominated in the Best PC Game category. In 2012, at the British Academy Video Games Awards, Minecraft was nominated in the GAME Award of 2011 category and Persson received The Special Award. In 2012, Minecraft XBLA was awarded a Golden Joystick Award in the Best Downloadable Game category, and a TIGA Games Industry Award in the Best Arcade Game category. In 2013, it was nominated as the family game of the year at the British Academy Video Games Awards. During the 16th Annual D.I.C.E. Awards, the Academy of Interactive Arts & Sciences nominated the Xbox 360 version of Minecraft for "Strategy/Simulation Game of the Year". Minecraft Console Edition won the award for TIGA Game Of The Year in 2014. In 2015, the game placed 6th on USgamer's The 15 Best Games Since 2000 list. In 2016, Minecraft placed 6th on Time's The 50 Best Video Games of All Time list. Minecraft was nominated for the 2013 Kids' Choice Awards for Favorite App, but lost to Temple Run. It was nominated for the 2014 Kids' Choice Awards for Favorite Video Game, but lost to Just Dance 2014. The game later won the award for the Most Addicting Game at the 2015 Kids' Choice Awards. In addition, the Java Edition was nominated for "Favorite Video Game" at the 2018 Kids' Choice Awards, while the game itself won the "Still Playing" award at the 2019 Golden Joystick Awards, as well as the "Favorite Video Game" award at the 2020 Kids' Choice Awards. Minecraft also won "Stream Game of the Year" at inaugural Streamer Awards in 2021. The game later garnered a Nickelodeon Kids' Choice Award nomination for Favorite Video Game in 2021, and won the same category in 2022 and 2023. At the Golden Joystick Awards 2025, it won the Still Playing Award - PC and Console. Minecraft has been subject to several notable controversies. In June 2014, Mojang announced that it would begin enforcing the portion of Minecraft's end-user license agreement (EULA) which prohibits servers from giving in-game advantages to players in exchange for donations or payments. Spokesperson Owen Hill stated that servers could still require players to pay a fee to access the server and could sell in-game cosmetic items. The change was supported by Persson, citing emails he received from parents of children who had spent hundreds of dollars on servers. The Minecraft community and server owners protested, arguing that the EULA's terms were more broad than Mojang was claiming, that the crackdown would force smaller servers to shut down for financial reasons, and that Mojang was suppressing competition for its own Minecraft Realms subscription service. The controversy contributed to Notch's decision to sell Mojang. In 2020, Mojang announced an eventual change to the Java Edition to require a login from a Microsoft account rather than a Mojang account, the latter of which would be sunsetted. This also required Java Edition players to create Xbox network Gamertags. Mojang defended the move to Microsoft accounts by saying that improved security could be offered, including two-factor authentication, blocking cyberbullies in chat, and improved parental controls. The community responded with intense backlash, citing various technical difficulties encountered in the process and how account migration would be mandatory, even for those who do not play on servers. As of 10 March 2022, Microsoft required that all players migrate in order to maintain access the Java Edition of Minecraft. Mojang announced a deadline of 19 September 2023 for account migration, after which all legacy Mojang accounts became inaccessible and unable to be migrated. In June 2022, Mojang added a player-reporting feature in Java Edition. Players could report other players on multiplayer servers for sending messages prohibited by the Xbox Live Code of Conduct; report categories included profane language,[l] substance abuse, hate speech, threats of violence, and nudity. If a player was found to be in violation of Xbox Community Standards, they would be banned from all servers for a specific period of time or permanently. The update containing the report feature (1.19.1) was released on 27 July 2022. Mojang received substantial backlash and protest from community members, one of the most common complaints being that banned players would be forbidden from joining any server, even private ones. Others took issue to what they saw as Microsoft increasing control over its player base and exercising censorship, leading some to start a hashtag #saveminecraft and dub the version "1.19.84", a reference to the dystopian novel Nineteen Eighty-Four. The "Mob Vote" was an online event organized by Mojang in which the Minecraft community voted between three original mob concepts; initially, the winning mob was to be implemented in a future update, while the losing mobs were scrapped, though after the first mob vote this was changed, and losing mobs would now have a chance to come to the game in the future. The first Mob Vote was held during Minecon Earth 2017 and became an annual event starting with Minecraft Live 2020. The Mob Vote was often criticized for forcing players to choose one mob instead of implementing all three, causing divisions and flaming within the community, and potentially allowing internet bots and Minecraft content creators with large fanbases to conduct vote brigading. The Mob Vote was also blamed for a perceived lack of new content added to Minecraft since Microsoft's acquisition of Mojang in 2014. The 2023 Mob Vote featured three passive mobs—the crab, the penguin, and the armadillo—with voting scheduled to start on 13 October. In response, a Change.org petition was created on 6 October, demanding that Mojang eliminate the Mob Vote and instead implement all three mobs going forward. The petition received approximately 445,000 signatures by 13 October and was joined by calls to boycott the Mob Vote, as well as a partially tongue-in-cheek "revolutionary" propaganda campaign in which sympathizers created anti-Mojang and pro-boycott posters in the vein of real 20th century propaganda posters. Mojang did not release an official response to the boycott, and the Mob Vote otherwise proceeded normally, with the armadillo winning the vote. In September 2024, as part of a blog post detailing their future plans for Minecraft's development, Mojang announced the Mob Vote would be retired. Cultural impact In September 2019, The Guardian classified Minecraft as the best video game of the 21st century to date, and in November 2019, Polygon called it the "most important game of the decade" in its 2010s "decade in review". In June 2020, Minecraft was inducted into the World Video Game Hall of Fame. Minecraft is recognized as one of the first successful games to use an early access model to draw in sales prior to its full release version to help fund development. As Minecraft helped to bolster indie game development in the early 2010s, it also helped to popularize the use of the early access model in indie game development. Social media sites such as YouTube, Facebook, and Reddit have played a significant role in popularizing Minecraft. Research conducted by the Annenberg School for Communication at the University of Pennsylvania showed that one-third of Minecraft players learned about the game via Internet videos. In 2010, Minecraft-related videos began to gain influence on YouTube, often made by commentators. The videos usually contain screen-capture footage of the game and voice-overs. Common coverage in the videos includes creations made by players, walkthroughs of various tasks, and parodies of works in popular culture. By May 2012, over four million Minecraft-related YouTube videos had been uploaded. The game would go on to be a prominent fixture within YouTube's gaming scene during the entire 2010s; in 2014, it was the second-most searched term on the entire platform. By 2018, it was still YouTube's biggest game globally. Some popular commentators have received employment at Machinima, a now-defunct gaming video company that owned a highly watched entertainment channel on YouTube. The Yogscast is a British company that regularly produces Minecraft videos; their YouTube channel has attained billions of views, and their panel at Minecon 2011 had the highest attendance. Another well-known YouTube personality is Jordan Maron, known online as CaptainSparklez, who has also created many Minecraft music parodies, including "Revenge", a parody of Usher's "DJ Got Us Fallin' in Love". Minecraft's popularity on YouTube was described by Polygon as quietly dominant, although in 2019, thanks in part to PewDiePie's playthroughs of the game, Minecraft experienced a visible uptick in popularity on the platform. Longer-running series include Far Lands or Bust, dedicated to reaching the obsolete "Far Lands" glitch by foot on an older version of the game. YouTube announced that on 14 December 2021 that the total amount of Minecraft-related views on the website had exceeded one trillion. Minecraft has been referenced by other video games, such as Torchlight II, Team Fortress 2, Borderlands 2, Choplifter HD, Super Meat Boy, The Elder Scrolls V: Skyrim, The Binding of Isaac, The Stanley Parable, and FTL: Faster Than Light. Minecraft is officially represented in downloadable content for the crossover fighter Super Smash Bros. Ultimate, with Steve as a playable character with a moveset including references to building, crafting, and redstone, alongside an Overworld-themed stage. It was also referenced by electronic music artist Deadmau5 in his performances. The game is also referenced heavily in "Informative Murder Porn", the second episode of the seventeenth season of the animated television series South Park. In 2025, A Minecraft Movie was released. It made $313 million in the box office in the first week, a record-breaking opening for a video game adaptation. Minecraft has been noted as a cultural touchstone for Generation Z, as many of the generation's members played the game at a young age. The possible applications of Minecraft have been discussed extensively, especially in the fields of computer-aided design (CAD) and education. In a panel at Minecon 2011, a Swedish developer discussed the possibility of using the game to redesign public buildings and parks, stating that rendering using Minecraft was much more user-friendly for the community, making it easier to envision the functionality of new buildings and parks. In 2012, a member of the Human Dynamics group at the MIT Media Lab, Cody Sumter, said: "Notch hasn't just built a game. He's tricked 40 million people into learning to use a CAD program." Various software has been developed to allow virtual designs to be printed using professional 3D printers or personal printers such as MakerBot and RepRap. In September 2012, Mojang began the Block by Block project in cooperation with UN Habitat to create real-world environments in Minecraft. The project allows young people who live in those environments to participate in designing the changes they would like to see. Using Minecraft, the community has helped reconstruct the areas of concern, and citizens are invited to enter the Minecraft servers and modify their own neighborhood. Carl Manneh, Mojang's managing director, called the game "the perfect tool to facilitate this process", adding "The three-year partnership will support UN-Habitat's Sustainable Urban Development Network to upgrade 300 public spaces by 2016." Mojang signed Minecraft building community, FyreUK, to help render the environments into Minecraft. The first pilot project began in Kibera, one of Nairobi's informal settlements and is in the planning phase. The Block by Block project is based on an earlier initiative started in October 2011, Mina Kvarter (My Block), which gave young people in Swedish communities a tool to visualize how they wanted to change their part of town. According to Manneh, the project was a helpful way to visualize urban planning ideas without necessarily having a training in architecture. The ideas presented by the citizens were a template for political decisions. In April 2014, the Danish Geodata Agency generated all of Denmark in fullscale in Minecraft based on their own geodata. This is possible because Denmark is one of the flattest countries with the highest point at 171 meters (ranking as the country with the 30th smallest elevation span), where the limit in default Minecraft was around 192 meters above in-game sea level when the project was completed. Taking advantage of the game's accessibility where other websites are censored, the non-governmental organization Reporters Without Borders has used an open Minecraft server to create the Uncensored Library, a repository within the game of journalism by authors from countries (including Egypt, Mexico, Russia, Saudi Arabia and Vietnam) who have been censored and arrested, such as Jamal Khashoggi. The neoclassical virtual building was created over about 250 hours by an international team of 24 people. Despite its unpredictable nature, Minecraft speedrunning, where players time themselves from spawning into a new world to reaching The End and defeating the Ender Dragon boss, is popular. Some speedrunners use a combination of mods, external programs, and debug menus, while other runners play the game in a more vanilla or more consistency-oriented way. Minecraft has been used in educational settings through initiatives such as MinecraftEdu, founded in 2011 to make the game affordable and accessible for schools in collaboration with Mojang. MinecraftEdu provided features allowing teachers to monitor student progress, including screenshot submissions as evidence of lesson completion, and by 2012 reported that approximately 250,000 students worldwide had access to the platform. Mojang also developed Minecraft: Education Edition with pre-built lesson plans for up to 30 students in a closed environment. Educators have used Minecraft to teach subjects such as history, language arts, and science through custom-built environments, including reconstructions of historical landmarks and large-scale models of biological structures such as animal cells. The introduction of redstone blocks enabled the construction of functional virtual machines such as a hard drive and an 8-bit computer. Mods have been created to use these mechanics for teaching programming. In 2014, the British Museum announced a project to reproduce its building and exhibits in Minecraft in collaboration with the public. Microsoft and Code.org have offered Minecraft-based tutorials and activities designed to teach programming, reporting by 2018 that more than 85 million children had used their resources. In 2025, the Musée de Minéralogie in Paris held a temporary exhibition titled "Minerals in Minecraft." Following the initial surge in popularity of Minecraft in 2010, other video games were criticised for having various similarities to Minecraft, and some were described as being "clones", often due to a direct inspiration from Minecraft, or a superficial similarity. Examples include Ace of Spades, CastleMiner, CraftWorld, FortressCraft, Terraria, BlockWorld 3D, Total Miner, and Luanti (formerly Minetest). David Frampton, designer of The Blockheads, reported that one failure of his 2D game was the "low resolution pixel art" that too closely resembled the art in Minecraft, which resulted in "some resistance" from fans. A homebrew adaptation of the alpha version of Minecraft for the Nintendo DS, titled DScraft, has been released; it has been noted for its similarity to the original game considering the technical limitations of the system. In response to Microsoft's acquisition of Mojang and their Minecraft IP, various developers announced further clone titles developed specifically for Nintendo's consoles, as they were the only major platforms not to officially receive Minecraft at the time. These clone titles include UCraft (Nexis Games), Cube Life: Island Survival (Cypronia), Discovery (Noowanda), Battleminer (Wobbly Tooth Games), Cube Creator 3D (Big John Games), and Stone Shire (Finger Gun Games). Despite this, the fears of fans were unfounded, with official Minecraft releases on Nintendo consoles eventually resuming. Markus Persson made another similar game, Minicraft, for a Ludum Dare competition in 2011. In 2025, Persson announced through a poll on his X account that he was considering developing a spiritual successor to Minecraft. He later clarified that he was "100% serious", and that he had "basically announced Minecraft 2". Within days, however, Persson cancelled the plans after speaking to his team. In November 2024, artificial intelligence companies Decart and Etched released Oasis, an artificially generated version of Minecraft, as a proof of concept. Every in-game element is completely AI-generated in real time and the model does not store world data, leading to "hallucinations" such as items and blocks appearing that were not there before. In January 2026, indie game developer Unomelon announced that their voxel sandbox game Allumeria would be playable in Steam Next Fest that year. On 10 February, Mojang issued a DMCA takedown of Allumeria on Steam through Valve, alleging the game was infringing on Minecraft's copyright. Some reports suggested that the takedown may have used an automatic AI copyright claiming service. The DMCA was later withdrawn. Minecon was an annual official fan convention dedicated to Minecraft. The first full Minecon was held in November 2011 at the Mandalay Bay Hotel and Casino in Las Vegas. The event included the official launch of Minecraft; keynote speeches, including one by Persson; building and costume contests; Minecraft-themed breakout classes; exhibits by leading gaming and Minecraft-related companies; commemorative merchandise; and autograph and picture times with Mojang employees and well-known contributors from the Minecraft community. In 2016, Minecon was held in-person for the last time, with the following years featuring annual "Minecon Earth" livestreams on minecraft.net and YouTube instead. These livestreams, later rebranded to "Minecraft Live", included the mob/biome votes, and announcements of new game updates. In 2025, "Minecraft Live" became a biannual event as part of Minecraft's changing update schedule.[citation needed] Notes References External links |
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