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Contents Elon Musk Elon Reeve Musk (/ˈiːlɒn/ EE-lon; born June 28, 1971) is a businessman and entrepreneur known for his leadership of Tesla, SpaceX, Twitter, and xAI. Musk has been the wealthiest person in the world since 2025; as of February 2026,[update] Forbes estimates his net worth to be around US$852 billion. Born into a wealthy family in Pretoria, South Africa, Musk emigrated in 1989 to Canada; he has Canadian citizenship since his mother was born there. He received bachelor's degrees in 1997 from the University of Pennsylvania before moving to California to pursue business ventures. In 1995, Musk co-founded the software company Zip2. Following its sale in 1999, he co-founded X.com, an online payment company that later merged to form PayPal, which was acquired by eBay in 2002. Musk also became an American citizen in 2002. In 2002, Musk founded the space technology company SpaceX, becoming its CEO and chief engineer; the company has since led innovations in reusable rockets and commercial spaceflight. Musk joined the automaker Tesla as an early investor in 2004 and became its CEO and product architect in 2008; it has since become a leader in electric vehicles. In 2015, he co-founded OpenAI to advance artificial intelligence (AI) research, but later left; growing discontent with the organization's direction and their leadership in the AI boom in the 2020s led him to establish xAI, which became a subsidiary of SpaceX in 2026. In 2022, he acquired the social network Twitter, implementing significant changes, and rebranding it as X in 2023. His other businesses include the neurotechnology company Neuralink, which he co-founded in 2016, and the tunneling company the Boring Company, which he founded in 2017. In November 2025, a Tesla pay package worth $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Musk was the largest donor in the 2024 U.S. presidential election, where he supported Donald Trump. After Trump was inaugurated as president in early 2025, Musk served as Senior Advisor to the President and as the de facto head of the Department of Government Efficiency (DOGE). After a public feud with Trump, Musk left the Trump administration and returned to managing his companies. Musk is a supporter of global far-right figures, causes, and political parties. His political activities, views, and statements have made him a polarizing figure. Musk has been criticized for COVID-19 misinformation, promoting conspiracy theories, and affirming antisemitic, racist, and transphobic comments. His acquisition of Twitter was controversial due to a subsequent increase in hate speech and the spread of misinformation on the service, following his pledge to decrease censorship. His role in the second Trump administration attracted public backlash, particularly in response to DOGE. The emails he sent to Jeffrey Epstein are included in the Epstein files, which were published between 2025–26 and became a topic of worldwide debate. Early life Elon Reeve Musk was born on June 28, 1971, in Pretoria, South Africa's administrative capital. He is of British and Pennsylvania Dutch ancestry. His mother, Maye (née Haldeman), is a model and dietitian born in Saskatchewan, Canada, and raised in South Africa. Musk therefore holds both South African and Canadian citizenship from birth. His father, Errol Musk, is a South African electromechanical engineer, pilot, sailor, consultant, emerald dealer, and property developer, who partly owned a rental lodge at Timbavati Private Nature Reserve. His maternal grandfather, Joshua N. Haldeman, who died in a plane crash when Elon was a toddler, was an American-born Canadian chiropractor, aviator and political activist in the technocracy movement who moved to South Africa in 1950. Elon has a younger brother, Kimbal, a younger sister, Tosca, and four paternal half-siblings. Musk was baptized as a child in the Anglican Church of Southern Africa. Despite both Elon and Errol previously stating that Errol was a part owner of a Zambian emerald mine, in 2023, Errol recounted that the deal he made was to receive "a portion of the emeralds produced at three small mines". Errol was elected to the Pretoria City Council as a representative of the anti-apartheid Progressive Party and has said that his children shared their father's dislike of apartheid. After his parents divorced in 1979, Elon, aged around 9, chose to live with his father because Errol Musk had an Encyclopædia Britannica and a computer. Elon later regretted his decision and became estranged from his father. Elon has recounted trips to a wilderness school that he described as a "paramilitary Lord of the Flies" where "bullying was a virtue" and children were encouraged to fight over rations. In one incident, after an altercation with a fellow pupil, Elon was thrown down concrete steps and beaten severely, leading to him being hospitalized for his injuries. Elon described his father berating him after he was discharged from the hospital. Errol denied berating Elon and claimed, "The [other] boy had just lost his father to suicide, and Elon had called him stupid. Elon had a tendency to call people stupid. How could I possibly blame that child?" Elon was an enthusiastic reader of books, and had attributed his success in part to having read The Lord of the Rings, the Foundation series, and The Hitchhiker's Guide to the Galaxy. At age ten, he developed an interest in computing and video games, teaching himself how to program from the VIC-20 user manual. At age twelve, Elon sold his BASIC-based game Blastar to PC and Office Technology magazine for approximately $500 (equivalent to $1,600 in 2025). Musk attended Waterkloof House Preparatory School, Bryanston High School, and then Pretoria Boys High School, where he graduated. Musk was a decent but unexceptional student, earning a 61/100 in Afrikaans and a B on his senior math certification. Musk applied for a Canadian passport through his Canadian-born mother to avoid South Africa's mandatory military service, which would have forced him to participate in the apartheid regime, as well as to ease his path to immigration to the United States. While waiting for his application to be processed, he attended the University of Pretoria for five months. Musk arrived in Canada in June 1989, connected with a second cousin in Saskatchewan, and worked odd jobs, including at a farm and a lumber mill. In 1990, he entered Queen's University in Kingston, Ontario. Two years later, he transferred to the University of Pennsylvania, where he studied until 1995. Although Musk has said that he earned his degrees in 1995, the University of Pennsylvania did not award them until 1997 – a Bachelor of Arts in physics and a Bachelor of Science in economics from the university's Wharton School. He reportedly hosted large, ticketed house parties to help pay for tuition, and wrote a business plan for an electronic book-scanning service similar to Google Books. In 1994, Musk held two internships in Silicon Valley: one at energy storage startup Pinnacle Research Institute, which investigated electrolytic supercapacitors for energy storage, and another at Palo Alto–based startup Rocket Science Games. In 1995, he was accepted to a graduate program in materials science at Stanford University, but did not enroll. Musk decided to join the Internet boom of the 1990s, applying for a job at Netscape, to which he reportedly never received a response. The Washington Post reported that Musk lacked legal authorization to remain and work in the United States after failing to enroll at Stanford. In response, Musk said he was allowed to work at that time and that his student visa transitioned to an H1-B. According to numerous former business associates and shareholders, Musk said he was on a student visa at the time. Business career In 1995, Musk, his brother Kimbal, and Greg Kouri founded the web software company Zip2 with funding from a group of angel investors. They housed the venture at a small rented office in Palo Alto. Replying to Rolling Stone, Musk denounced the notion that they started their company with funds borrowed from Errol Musk, but in a tweet, he recognized that his father contributed 10% of a later funding round. The company developed and marketed an Internet city guide for the newspaper publishing industry, with maps, directions, and yellow pages. According to Musk, "The website was up during the day and I was coding it at night, seven days a week, all the time." To impress investors, Musk built a large plastic structure around a standard computer to create the impression that Zip2 was powered by a small supercomputer. The Musk brothers obtained contracts with The New York Times and the Chicago Tribune, and persuaded the board of directors to abandon plans for a merger with CitySearch. Musk's attempts to become CEO were thwarted by the board. Compaq acquired Zip2 for $307 million in cash in February 1999 (equivalent to $590,000,000 in 2025), and Musk received $22 million (equivalent to $43,000,000 in 2025) for his 7-percent share. In 1999, Musk co-founded X.com, an online financial services and e-mail payment company. The startup was one of the first federally insured online banks, and, in its initial months of operation, over 200,000 customers joined the service. The company's investors regarded Musk as inexperienced and replaced him with Intuit CEO Bill Harris by the end of the year. The following year, X.com merged with online bank Confinity to avoid competition. Founded by Max Levchin and Peter Thiel, Confinity had its own money-transfer service, PayPal, which was more popular than X.com's service. Within the merged company, Musk returned as CEO. Musk's preference for Microsoft software over Unix created a rift in the company and caused Thiel to resign. Due to resulting technological issues and lack of a cohesive business model, the board ousted Musk and replaced him with Thiel in 2000.[b] Under Thiel, the company focused on the PayPal service and was renamed PayPal in 2001. In 2002, PayPal was acquired by eBay for $1.5 billion (equivalent to $2,700,000,000 in 2025) in stock, of which Musk—the largest shareholder with 11.72% of shares—received $175.8 million (equivalent to $320,000,000 in 2025). In 2017, Musk purchased the domain X.com from PayPal for an undisclosed amount, stating that it had sentimental value. In 2001, Musk became involved with the nonprofit Mars Society and discussed funding plans to place a growth-chamber for plants on Mars. Seeking a way to launch the greenhouse payloads into space, Musk made two unsuccessful trips to Moscow to purchase intercontinental ballistic missiles (ICBMs) from Russian companies NPO Lavochkin and Kosmotras. Musk instead decided to start a company to build affordable rockets. With $100 million of his early fortune, (equivalent to $180,000,000 in 2025) Musk founded SpaceX in May 2002 and became the company's CEO and Chief Engineer. SpaceX attempted its first launch of the Falcon 1 rocket in 2006. Although the rocket failed to reach Earth orbit, it was awarded a Commercial Orbital Transportation Services program contract from NASA, then led by Mike Griffin. After two more failed attempts that nearly caused Musk to go bankrupt, SpaceX succeeded in launching the Falcon 1 into orbit in 2008. Later that year, SpaceX received a $1.6 billion NASA contract (equivalent to $2,400,000,000 in 2025) for Falcon 9-launched Dragon spacecraft flights to the International Space Station (ISS), replacing the Space Shuttle after its 2011 retirement. In 2012, the Dragon vehicle docked with the ISS, a first for a commercial spacecraft. Working towards its goal of reusable rockets, in 2015 SpaceX successfully landed the first stage of a Falcon 9 on a land platform. Later landings were achieved on autonomous spaceport drone ships, an ocean-based recovery platform. In 2018, SpaceX launched the Falcon Heavy; the inaugural mission carried Musk's personal Tesla Roadster as a dummy payload. Since 2019, SpaceX has been developing Starship, a reusable, super heavy-lift launch vehicle intended to replace the Falcon 9 and Falcon Heavy. In 2020, SpaceX launched its first crewed flight, the Demo-2, becoming the first private company to place astronauts into orbit and dock a crewed spacecraft with the ISS. In 2024, NASA awarded SpaceX an $843 million (equivalent to $865,000,000 in 2025) contract to build a spacecraft that NASA will use to deorbit the ISS at the end of its lifespan. In 2015, SpaceX began development of the Starlink constellation of low Earth orbit satellites to provide satellite Internet access. After the launch of prototype satellites in 2018, the first large constellation was deployed in May 2019. As of May 2025[update], over 7,600 Starlink satellites are operational, comprising 65% of all operational Earth satellites. The total cost of the decade-long project to design, build, and deploy the constellation was estimated by SpaceX in 2020 to be $10 billion (equivalent to $12,000,000,000 in 2025).[c] During the Russian invasion of Ukraine, Musk provided free Starlink service to Ukraine, permitting Internet access and communication at a yearly cost to SpaceX of $400 million (equivalent to $440,000,000 in 2025). However, Musk refused to block Russian state media on Starlink. In 2023, Musk denied Ukraine's request to activate Starlink over Crimea to aid an attack against the Russian navy, citing fears of a nuclear response. Tesla, Inc., originally Tesla Motors, was incorporated in July 2003 by Martin Eberhard and Marc Tarpenning. Both men played active roles in the company's early development prior to Musk's involvement. Musk led the Series A round of investment in February 2004; he invested $6.35 million (equivalent to $11,000,000 in 2025), became the majority shareholder, and joined Tesla's board of directors as chairman. Musk took an active role within the company and oversaw Roadster product design, but was not deeply involved in day-to-day business operations. Following a series of escalating conflicts in 2007 and the 2008 financial crisis, Eberhard was ousted from the firm.[page needed] Musk assumed leadership of the company as CEO and product architect in 2008. A 2009 lawsuit settlement with Eberhard designated Musk as a Tesla co-founder, along with Tarpenning and two others. Tesla began delivery of the Roadster, an electric sports car, in 2008. With sales of about 2,500 vehicles, it was the first mass production all-electric car to use lithium-ion battery cells. Under Musk, Tesla has since launched several well-selling electric vehicles, including the four-door sedan Model S (2012), the crossover Model X (2015), the mass-market sedan Model 3 (2017), the crossover Model Y (2020), and the pickup truck Cybertruck (2023). In May 2020, Musk resigned as chairman of the board as part of the settlement of a lawsuit from the SEC over him tweeting that funding had been "secured" for potentially taking Tesla private. The company has also constructed multiple lithium-ion battery and electric vehicle factories, called Gigafactories. Since its initial public offering in 2010, Tesla stock has risen significantly; it became the most valuable carmaker in summer 2020, and it entered the S&P 500 later that year. In October 2021, it reached a market capitalization of $1 trillion (equivalent to $1,200,000,000,000 in 2025), the sixth company in U.S. history to do so. Musk provided the initial concept and financial capital for SolarCity, which his cousins Lyndon and Peter Rive founded in 2006. By 2013, SolarCity was the second largest provider of solar power systems in the United States. In 2014, Musk promoted the idea of SolarCity building an advanced production facility in Buffalo, New York, triple the size of the largest solar plant in the United States. Construction of the factory started in 2014 and was completed in 2017. It operated as a joint venture with Panasonic until early 2020. Tesla acquired SolarCity for $2 billion in 2016 (equivalent to $2,700,000,000 in 2025) and merged it with its battery unit to create Tesla Energy. The deal's announcement resulted in a more than 10% drop in Tesla's stock price; at the time, SolarCity was facing liquidity issues. Multiple shareholder groups filed a lawsuit against Musk and Tesla's directors, stating that the purchase of SolarCity was done solely to benefit Musk and came at the expense of Tesla and its shareholders. Tesla directors settled the lawsuit in January 2020, leaving Musk the sole remaining defendant. Two years later, the court ruled in Musk's favor. In 2016, Musk co-founded Neuralink, a neurotechnology startup, with an investment of $100 million. Neuralink aims to integrate the human brain with artificial intelligence (AI) by creating devices that are embedded in the brain. Such technology could enhance memory or allow the devices to communicate with software. The company also hopes to develop devices to treat neurological conditions like spinal cord injuries. In 2022, Neuralink announced that clinical trials would begin by the end of the year. In September 2023, the Food and Drug Administration approved Neuralink to initiate six-year human trials. Neuralink has conducted animal testing on macaques at the University of California, Davis. In 2021, the company released a video in which a macaque played the video game Pong via a Neuralink implant. The company's animal trials—which have caused the deaths of some monkeys—have led to claims of animal cruelty. The Physicians Committee for Responsible Medicine has alleged that Neuralink violated the Animal Welfare Act. Employees have complained that pressure from Musk to accelerate development has led to botched experiments and unnecessary animal deaths. In 2022, a federal probe was launched into possible animal welfare violations by Neuralink.[needs update] In 2017, Musk founded the Boring Company to construct tunnels; he also revealed plans for specialized, underground, high-occupancy vehicles that could travel up to 150 miles per hour (240 km/h) and thus circumvent above-ground traffic in major cities. Early in 2017, the company began discussions with regulatory bodies and initiated construction of a 30-foot (9.1 m) wide, 50-foot (15 m) long, and 15-foot (4.6 m) deep "test trench" on the premises of SpaceX's offices, as that required no permits. The Los Angeles tunnel, less than two miles (3.2 km) in length, debuted to journalists in 2018. It used Tesla Model Xs and was reported to be a rough ride while traveling at suboptimal speeds. Two tunnel projects announced in 2018, in Chicago and West Los Angeles, have been canceled. A tunnel beneath the Las Vegas Convention Center was completed in early 2021. Local officials have approved further expansions of the tunnel system. April 14, 2022 In early 2017, Musk expressed interest in buying Twitter and had questioned the platform's commitment to freedom of speech. By 2022, Musk had reached 9.2% stake in the company, making him the largest shareholder.[d] Musk later agreed to a deal that would appoint him to Twitter's board of directors and prohibit him from acquiring more than 14.9% of the company. Days later, Musk made a $43 billion offer to buy Twitter. By the end of April Musk had successfully concluded his bid for approximately $44 billion. This included approximately $12.5 billion in loans and $21 billion in equity financing. Having backtracked on his initial decision, Musk bought the company on October 27, 2022. Immediately after the acquisition, Musk fired several top Twitter executives including CEO Parag Agrawal; Musk became the CEO instead. Under Elon Musk, Twitter instituted monthly subscriptions for a "blue check", and laid off a significant portion of the company's staff. Musk lessened content moderation and hate speech also increased on the platform after his takeover. In late 2022, Musk released internal documents relating to Twitter's moderation of Hunter Biden's laptop controversy in the lead-up to the 2020 presidential election. Musk also promised to step down as CEO after a Twitter poll, and five months later, Musk stepped down as CEO and transitioned his role to executive chairman and chief technology officer (CTO). Despite Musk stepping down as CEO, X continues to struggle with challenges such as viral misinformation, hate speech, and antisemitism controversies. Musk has been accused of trying to silence some of his critics such as Twitch streamer Asmongold, who criticized him during one of his streams. Musk has been accused of removing their accounts' blue checkmarks, which hinders visibility and is considered a form of shadow banning, or suspending their accounts without justification. Other activities In August 2013, Musk announced plans for a version of a vactrain, and assigned engineers from SpaceX and Tesla to design a transport system between Greater Los Angeles and the San Francisco Bay Area, at an estimated cost of $6 billion. Later that year, Musk unveiled the concept, dubbed the Hyperloop, intended to make travel cheaper than any other mode of transport for such long distances. In December 2015, Musk co-founded OpenAI, a not-for-profit artificial intelligence (AI) research company aiming to develop artificial general intelligence, intended to be safe and beneficial to humanity. Musk pledged $1 billion of funding to the company, and initially gave $50 million. In 2018, Musk left the OpenAI board. Since 2018, OpenAI has made significant advances in machine learning. In July 2023, Musk launched the artificial intelligence company xAI, which aims to develop a generative AI program that competes with existing offerings like OpenAI's ChatGPT. Musk obtained funding from investors in SpaceX and Tesla, and xAI hired engineers from Google and OpenAI. December 16, 2022 Musk uses a private jet owned by Falcon Landing LLC, a SpaceX-linked company, and acquired a second jet in August 2020. His heavy use of the jets and the consequent fossil fuel usage have received criticism. Musk's flight usage is tracked on social media through ElonJet. In December 2022, Musk banned the ElonJet account on Twitter, and made temporary bans on the accounts of journalists that posted stories regarding the incident, including Donie O'Sullivan, Keith Olbermann, and journalists from The New York Times, The Washington Post, CNN, and The Intercept. In October 2025, Musk's company xAI launched Grokipedia, an AI-generated online encyclopedia that he promoted as an alternative to Wikipedia. Articles on Grokipedia are generated and reviewed by xAI's Grok chatbot. Media coverage and academic analysis described Grokipedia as frequently reusing Wikipedia content but framing contested political and social topics in line with Musk's own views and right-wing narratives. A study by Cornell University researchers and NBC News stated that Grokipedia cites sources that are blacklisted or considered "generally unreliable" on Wikipedia, for example, the conspiracy site Infowars and the neo-Nazi forum Stormfront. Wired, The Guardian and Time criticized Grokipedia for factual errors and for presenting Musk himself in unusually positive terms while downplaying controversies. Politics Musk is an outlier among business leaders who typically avoid partisan political advocacy. Musk was a registered independent voter when he lived in California. Historically, he has donated to both Democrats and Republicans, many of whom serve in states in which he has a vested interest. Since 2022, his political contributions have mostly supported Republicans, with his first vote for a Republican going to Mayra Flores in the 2022 Texas's 34th congressional district special election. In 2024, he started supporting international far-right political parties, activists, and causes, and has shared misinformation and numerous conspiracy theories. Since 2024, his views have been generally described as right-wing. Musk supported Barack Obama in 2008 and 2012, Hillary Clinton in 2016, Joe Biden in 2020, and Donald Trump in 2024. In the 2020 Democratic Party presidential primaries, Musk endorsed candidate Andrew Yang and expressed support for Yang's proposed universal basic income, and endorsed Kanye West's 2020 presidential campaign. In 2021, Musk publicly expressed opposition to the Build Back Better Act, a $3.5 trillion legislative package endorsed by Joe Biden that ultimately failed to pass due to unanimous opposition from congressional Republicans and several Democrats. In 2022, gave over $50 million to Citizens for Sanity, a conservative political action committee. In 2023, he supported Republican Ron DeSantis for the 2024 U.S. presidential election, giving $10 million to his campaign, and hosted DeSantis's campaign announcement on a Twitter Spaces event. From June 2023 to January 2024, Musk hosted a bipartisan set of X Spaces with Republican and Democratic candidates, including Robert F. Kennedy Jr., Vivek Ramaswamy, and Dean Phillips. In October 2025, former vice-president Kamala Harris commented that it was a mistake from the Democratic side to not invite Musk to a White House electric vehicle event organized in August 2021 and featuring executives from General Motors, Ford and Stellantis, despite Tesla being "the major American manufacturer of extraordinary innovation in this space." Fortune remarked that this was a nod to United Auto Workers and organized labor. Harris said presidents should put aside political loyalties when it came to recognizing innovation, and guessed that the non-invitation impacted Musk's perspective. Fortune noted that, at the time, Musk said, "Yeah, seems odd that Tesla wasn't invited." A month later, he criticized Biden as "not the friendliest administration." Jacob Silverman, author of the book Gilded Rage: Elon Musk and the Radicalization of Silicon Valley, said that the tech industry represented by Musk, Thiel, Andreessen and other capitalists, actually flourished under Biden, but the tech leaders chose Trump for their common ground on cultural issues. By early 2024, Musk had become a vocal and financial supporter of Donald Trump. In July 2024, minutes after the attempted assassination of Donald Trump, Musk endorsed him for president saying; "I fully endorse President Trump and hope for his rapid recovery." During the presidential campaign, Musk joined Trump on stage at a campaign rally, and during the campaign promoted conspiracy theories and falsehoods about Democrats, election fraud and immigration, in support of Trump. Musk was the largest individual donor of the 2024 election. In 2025, Musk contributed $19 million to the Wisconsin Supreme Court race, hoping to influence the state's future redistricting efforts and its regulations governing car manufacturers and dealers. In 2023, Musk said he shunned the World Economic Forum because it was boring. The organization commented that they had not invited him since 2015. He has participated in Dialog, dubbed "Tech Bilderberg" and organized by Peter Thiel and Auren Hoffman, though. Musk's international political actions and comments have come under increasing scrutiny and criticism, especially from the governments and leaders of France, Germany, Norway, Spain and the United Kingdom, particularly due to his position in the U.S. government as well as ownership of X. An NBC News analysis found he had boosted far-right political movements to cut immigration and curtail regulation of business in at least 18 countries on six continents since 2023. During his speech after the second inauguration of Donald Trump, Musk twice made a gesture interpreted by many as a Nazi or a fascist Roman salute.[e] He thumped his right hand over his heart, fingers spread wide, and then extended his right arm out, emphatically, at an upward angle, palm down and fingers together. He then repeated the gesture to the crowd behind him. As he finished the gestures, he said to the crowd, "My heart goes out to you. It is thanks to you that the future of civilization is assured." It was widely condemned as an intentional Nazi salute in Germany, where making such gestures is illegal. The Anti-Defamation League said it was not a Nazi salute, but other Jewish organizations disagreed and condemned the salute. American public opinion was divided on partisan lines as to whether it was a fascist salute. Musk dismissed the accusations of Nazi sympathies, deriding them as "dirty tricks" and a "tired" attack. Neo-Nazi and white supremacist groups celebrated it as a Nazi salute. Multiple European political parties demanded that Musk be banned from entering their countries. The concept of DOGE emerged in a discussion between Musk and Donald Trump, and in August 2024, Trump committed to giving Musk an advisory role, with Musk accepting the offer. In November and December 2024, Musk suggested that the organization could help to cut the U.S. federal budget, consolidate the number of federal agencies, and eliminate the Consumer Financial Protection Bureau, and that its final stage would be "deleting itself". In January 2025, the organization was created by executive order, and Musk was designated a "special government employee". Musk led the organization and was a senior advisor to the president, although his official role is not clear. In sworn statement during a lawsuit, the director of the White House Office of Administration stated that Musk "is not an employee of the U.S. DOGE Service or U.S. DOGE Service Temporary Organization", "is not the U.S. DOGE Service administrator", and has "no actual or formal authority to make government decisions himself". Trump said two days later that he had put Musk in charge of DOGE. A federal judge has ruled that Musk acted as the de facto leader of DOGE. Musk's role in the second Trump administration, particularly in response to DOGE, has attracted public backlash. He was criticized for his treatment of federal government employees, including his influence over the mass layoffs of the federal workforce. He has prioritized secrecy within the organization and has accused others of violating privacy laws. A Senate report alleged that Musk could avoid up to $2 billion in legal liability as a result of DOGE's actions. In May 2025, Bill Gates accused Musk of "killing the world's poorest children" through his cuts to USAID, which modeling by Boston University estimated had resulted in 300,000 deaths by this time, most of them of children. By November 2025, the estimated death toll had increased to 400,000 children and 200,000 adults. Musk announced on May 28, 2025, that he would depart from the Trump administration as planned when the special government employee's 130 day deadline expired, with a White House official confirming that Musk's offboarding from the Trump administration was already underway. His departure was officially confirmed during a joint Oval Office press conference with Trump on May 30, 2025. @realDonaldTrump is in the Epstein files. That is the real reason they have not been made public. June 5, 2025 After leaving office, Musk criticized the Trump administration's Big Beautiful Bill, calling it a "disgusting abomination" due to its provisions increasing the deficit. A feud began between Musk and Trump, with its most notable event being Musk alleging Trump had ties to sex offender Jeffrey Epstein on X (formerly Twitter) on June 5, 2025. Trump responded on Truth Social stating that Musk went "CRAZY" after the "EV Mandate" was purportedly taken away and threatened to cut Musk's government contracts. Musk then called for a third Trump impeachment. The next day, Trump stated that he did not wish to reconcile with Musk, and added that Musk would face "very serious consequences" if he funds Democratic candidates. On June 11, Musk publicly apologized for the tweets against Trump, saying they "went too far". Views November 6, 2022 Rejecting the conservative label, Musk has described himself as a political moderate, even as his views have become more right-wing over time. His views have been characterized as libertarian and far-right, and after his involvement in European politics, they have received criticism from world leaders such as Emmanuel Macron and Olaf Scholz. Within the context of American politics, Musk supported Democratic candidates up until 2022, at which point he voted for a Republican for the first time. He has stated support for universal basic income, gun rights, freedom of speech, a tax on carbon emissions, and H-1B visas. Musk has expressed concern about issues such as artificial intelligence (AI) and climate change, and has been a critic of wealth tax, short-selling, and government subsidies. An immigrant himself, Musk has been accused of being anti-immigration, and regularly blames immigration policies for illegal immigration. He is also a pronatalist who believes population decline is the biggest threat to civilization, and identifies as a cultural Christian. Musk has long been an advocate for space colonization, especially the colonization of Mars. He has repeatedly pushed for humanity colonizing Mars, in order to become an interplanetary species and lower the risks of human extinction. Musk has promoted conspiracy theories and made controversial statements that have led to accusations of racism, sexism, antisemitism, transphobia, disseminating disinformation, and support of white pride. While describing himself as a "pro-Semite", his comments regarding George Soros and Jewish communities have been condemned by the Anti-Defamation League and the Biden White House. Musk was criticized during the COVID-19 pandemic for making unfounded epidemiological claims, defying COVID-19 lockdowns restrictions, and supporting the Canada convoy protest against vaccine mandates. He has amplified false claims of white genocide in South Africa. Musk has been critical of Israel's actions in the Gaza Strip during the Gaza war, praised China's economic and climate goals, suggested that Taiwan and China should resolve cross-strait relations, and was described as having a close relationship with the Chinese government. In Europe, Musk expressed support for Ukraine in 2022 during the Russian invasion, recommended referendums and peace deals on the annexed Russia-occupied territories, and supported the far-right Alternative for Germany political party in 2024. Regarding British politics, Musk blamed the 2024 UK riots on mass migration and open borders, criticized Prime Minister Keir Starmer for what he described as a "two-tier" policing system, and was subsequently attacked as being responsible for spreading misinformation and amplifying the far-right. He has also voiced his support for far-right activist Tommy Robinson and pledged electoral support for Reform UK. In February 2026, Musk described Spanish Prime Minister Pedro Sánchez as a "tyrant" following Sánchez's proposal to prohibit minors under the age of 16 from accessing social media platforms. Legal affairs In 2018, Musk was sued by the U.S. Securities and Exchange Commission (SEC) for a tweet stating that funding had been secured for potentially taking Tesla private.[f] The securities fraud lawsuit characterized the tweet as false, misleading, and damaging to investors, and sought to bar Musk from serving as CEO of publicly traded companies. Two days later, Musk settled with the SEC, without admitting or denying the SEC's allegations. As a result, Musk and Tesla were fined $20 million each, and Musk was forced to step down for three years as Tesla chairman but was able to remain as CEO. Shareholders filed a lawsuit over the tweet, and in February 2023, a jury found Musk and Tesla not liable. Musk has stated in interviews that he does not regret posting the tweet that triggered the SEC investigation. In 2019, Musk stated in a tweet that Tesla would build half a million cars that year. The SEC reacted by asking a court to hold him in contempt for violating the terms of the 2018 settlement agreement. A joint agreement between Musk and the SEC eventually clarified the previous agreement details, including a list of topics about which Musk needed preclearance. In 2020, a judge blocked a lawsuit that claimed a tweet by Musk regarding Tesla stock price ("too high imo") violated the agreement. Freedom of Information Act (FOIA)-released records showed that the SEC concluded Musk had subsequently violated the agreement twice by tweeting regarding "Tesla's solar roof production volumes and its stock price". In October 2023, the SEC sued Musk over his refusal to testify a third time in an investigation into whether he violated federal law by purchasing Twitter stock in 2022. In February 2024, Judge Laurel Beeler ruled that Musk must testify again. In January 2025, the SEC filed a lawsuit against Musk for securities violations related to his purchase of Twitter. In January 2024, Delaware judge Kathaleen McCormick ruled in a 2018 lawsuit that Musk's $55 billion pay package from Tesla be rescinded. McCormick called the compensation granted by the company's board "an unfathomable sum" that was unfair to shareholders. The Delaware Supreme Court overturned McCormick's decision in December 2025, restoring Musk's compensation package and awarding $1 in nominal damages. Personal life Musk became a U.S. citizen in 2002. From the early 2000s until late 2020, Musk resided in California, where both Tesla and SpaceX were founded. He then relocated to Cameron County, Texas, saying that California had become "complacent" about its economic success. While hosting Saturday Night Live in 2021, Musk stated that he has Asperger syndrome (an outdated term for autism spectrum disorder). When asked about his experience growing up with Asperger's syndrome in a TED2022 conference in Vancouver, Musk stated that "the social cues were not intuitive ... I would just tend to take things very literally ... but then that turned out to be wrong — [people were not] simply saying exactly what they mean, there's all sorts of other things that are meant, and [it] took me a while to figure that out." Musk suffers from back pain and has undergone several spine-related surgeries, including a disc replacement. In 2000, he contracted a severe case of malaria while on vacation in South Africa. Musk has stated he uses doctor-prescribed ketamine for occasional depression and that he doses "a small amount once every other week or something like that"; since January 2024, some media outlets have reported that he takes ketamine, marijuana, LSD, ecstasy, mushrooms, cocaine and other drugs. Musk at first refused to comment on his alleged drug use, before responding that he had not tested positive for drugs, and that if drugs somehow improved his productivity, "I would definitely take them!". The New York Times' investigations revealed Musk's overuse of ketamine and numerous other drugs, as well as strained family relationships and concerns from close associates who have become troubled by his public behavior as he became more involved in political activities and government work. According to The Washington Post, President Trump described Musk as "a big-time drug addict". Through his own label Emo G Records, Musk released a rap track, "RIP Harambe", on SoundCloud in March 2019. The following year, he released an EDM track, "Don't Doubt Ur Vibe", featuring his own lyrics and vocals. Musk plays video games, which he stated has a "'restoring effect' that helps his 'mental calibration'". Some games he plays include Quake, Diablo IV, Elden Ring, and Polytopia. Musk once claimed to be one of the world's top video game players but has since admitted to "account boosting", or cheating by hiring outside services to achieve top player rankings. Musk has justified the boosting by claiming that all top accounts do it so he has to as well to remain competitive. In 2024 and 2025, Musk criticized the video game Assassin's Creed Shadows and its creator Ubisoft for "woke" content. Musk posted to X that "DEI kills art" and specified the inclusion of the historical figure Yasuke in the Assassin's Creed game as offensive; he also called the game "terrible". Ubisoft responded by saying that Musk's comments were "just feeding hatred" and that they were focused on producing a game not pushing politics. Musk has fathered at least 14 children, one of whom died as an infant. The Wall Street Journal reported in 2025 that sources close to Musk suggest that the "true number of Musk's children is much higher than publicly known". He had six children with his first wife, Canadian author Justine Wilson, whom he met while attending Queen's University in Ontario, Canada; they married in 2000. In 2002, their first child Nevada Musk died of sudden infant death syndrome at the age of 10 weeks. After his death, the couple used in vitro fertilization (IVF) to continue their family; they had twins in 2004, followed by triplets in 2006. The couple divorced in 2008 and have shared custody of their children. The elder twin he had with Wilson came out as a trans woman and, in 2022, officially changed her name to Vivian Jenna Wilson, adopting her mother's surname because she no longer wished to be associated with Musk. Musk began dating English actress Talulah Riley in 2008. They married two years later at Dornoch Cathedral in Scotland. In 2012, the couple divorced, then remarried the following year. After briefly filing for divorce in 2014, Musk finalized a second divorce from Riley in 2016. Musk then dated the American actress Amber Heard for several months in 2017; he had reportedly been "pursuing" her since 2012. In 2018, Musk and Canadian musician Grimes confirmed they were dating. Grimes and Musk have three children, born in 2020, 2021, and 2022.[g] Musk and Grimes originally gave their eldest child the name "X Æ A-12", which would have violated California regulations as it contained characters that are not in the modern English alphabet; the names registered on the birth certificate are "X" as a first name, "Æ A-Xii" as a middle name, and "Musk" as a last name. They received criticism for choosing a name perceived to be impractical and difficult to pronounce; Musk has said the intended pronunciation is "X Ash A Twelve". Their second child was born via surrogacy. Despite the pregnancy, Musk confirmed reports that the couple were "semi-separated" in September 2021; in an interview with Time in December 2021, he said he was single. In October 2023, Grimes sued Musk over parental rights and custody of X Æ A-Xii. Elon Musk has taken X Æ A-Xii to multiple official events in Washington, D.C. during Trump's second term in office. Also in July 2022, The Wall Street Journal reported that Musk allegedly had an affair with Nicole Shanahan, the wife of Google co-founder Sergey Brin, in 2021, leading to their divorce the following year. Musk denied the report. Musk also had a relationship with Australian actress Natasha Bassett, who has been described as "an occasional girlfriend". In October 2024, The New York Times reported Musk bought a Texas compound for his children and their mothers, though Musk denied having done so. Musk also has four children with Shivon Zilis, director of operations and special projects at Neuralink: twins born via IVF in 2021, a child born in 2024 via surrogacy and a child born in 2025.[h] On February 14, 2025, Ashley St. Clair, an influencer and author, posted on X claiming to have given birth to Musk's son Romulus five months earlier, which media outlets reported as Musk's supposed thirteenth child.[i] On February 22, 2025, it was reported that St Clair had filed for sole custody of her five-month-old son and for Musk to be recognised as the child's father. On March 31, 2025, Musk wrote that, while he was unsure if he was the father of St. Clair's child, he had paid St. Clair $2.5 million and would continue paying her $500,000 per year.[j] Later reporting from the Wall Street Journal indicated that $1 million of these payments to St. Clair were structured as a loan. In 2014, Musk and Ghislaine Maxwell appeared together in a photograph taken at an Academy Awards after-party, which Musk later described as a "photobomb". The January 2026 Epstein files contain emails between Musk and Epstein from 2012 to 2013, after Epstein's first conviction. Emails released on January 30, 2026, indicated that Epstein invited Musk to visit his private island on multiple occasions. The correspondence showed that while Epstein repeatedly encouraged Musk to attend, Musk did not visit the island. In one instance, Musk discussed the possibility of attending a party with his then-wife Talulah Riley and asked which day would be the "wildest party"; according to the emails, the visit did not take place after Epstein later cancelled the plans.[k] On Christmas day in 2012, Musk emailed Epstein asking "Do you have any parties planned? I’ve been working to the edge of sanity this year and so, once my kids head home after Christmas, I really want to hit the party scene in St Barts or elsewhere and let loose. The invitation is much appreciated, but a peaceful island experience is the opposite of what I’m looking for". Epstein replied that the "ratio on my island" might make Musk's wife uncomfortable to which Musk responded, "Ratio is not a problem for Talulah". On September 11, 2013, Epstein sent an email asking Musk if he had any plans for coming to New York for the opening of the United Nations General Assembly where many "interesting people" would be coming to his house to which Musk responded that "Flying to NY to see UN diplomats do nothing would be an unwise use of time". Epstein responded by stating "Do you think i am retarded. Just kidding, there is no one over 25 and all very cute." Musk has denied any close relationship with Epstein and described him as a "creep" who attempted to ingratiate himself with influential people. When Musk was asked in 2019 if he introduced Epstein to Mark Zuckerberg, Musk responded: "I don’t recall introducing Epstein to anyone, as I don’t know the guy well enough to do so." The released emails nonetheless showed cordial exchanges on a range of topics, including Musk's inquiry about parties on the island. The correspondence also indicated that Musk suggested hosting Epstein at SpaceX, while Epstein separately discussed plans to tour SpaceX and bring "the girls", though there is no evidence that such a visit occurred. Musk has described the release of the files a "distraction", later accusing the second Trump administration of suppressing them to protect powerful individuals, including Trump himself.[l] Wealth Elon Musk is the wealthiest person in the world, with an estimated net worth of US$690 billion as of January 2026, according to the Bloomberg Billionaires Index, and $852 billion according to Forbes, primarily from his ownership stakes in SpaceX and Tesla. Having been first listed on the Forbes Billionaires List in 2012, around 75% of Musk's wealth was derived from Tesla stock in November 2020, although he describes himself as "cash poor". According to Forbes, he became the first person in the world to achieve a net worth of $300 billion in 2021; $400 billion in December 2024; $500 billion in October 2025; $600 billion in mid-December 2025; $700 billion later that month; and $800 billion in February 2026. In November 2025, a Tesla pay package worth potentially $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Public image Although his ventures have been highly influential within their separate industries starting in the 2000s, Musk only became a public figure in the early 2010s. He has been described as an eccentric who makes spontaneous and impactful decisions, while also often making controversial statements, contrary to other billionaires who prefer reclusiveness to protect their businesses. Musk's actions and his expressed views have made him a polarizing figure. Biographer Ashlee Vance described people's opinions of Musk as polarized due to his "part philosopher, part troll" persona on Twitter. He has drawn denouncement for using his platform to mock the self-selection of personal pronouns, while also receiving praise for bringing international attention to matters like British survivors of grooming gangs. Musk has been described as an American oligarch due to his extensive influence over public discourse, social media, industry, politics, and government policy. After Trump's re-election, Musk's influence and actions during the transition period and the second presidency of Donald Trump led some to call him "President Musk", the "actual president-elect", "shadow president" or "co-president". Awards for his contributions to the development of the Falcon rockets include the American Institute of Aeronautics and Astronautics George Low Transportation Award in 2008, the Fédération Aéronautique Internationale Gold Space Medal in 2010, and the Royal Aeronautical Society Gold Medal in 2012. In 2015, he received an honorary doctorate in engineering and technology from Yale University and an Institute of Electrical and Electronics Engineers Honorary Membership. Musk was elected a Fellow of the Royal Society (FRS) in 2018.[m] In 2022, Musk was elected to the National Academy of Engineering. Time has listed Musk as one of the most influential people in the world in 2010, 2013, 2018, and 2021. Musk was selected as Time's "Person of the Year" for 2021. Then Time editor-in-chief Edward Felsenthal wrote that, "Person of the Year is a marker of influence, and few individuals have had more influence than Musk on life on Earth, and potentially life off Earth too." Notes References Works cited Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Hunter_Biden_laptop_controversy] | [TOKENS: 9247] |
Contents Hunter Biden laptop controversy In October 2020, a controversy arose involving a laptop that belonged to Hunter Biden. The owner of a Delaware computer shop, John Paul Mac Isaac, said that the laptop had been left by a man who identified himself as Hunter Biden. Mac Isaac also stated that he is legally blind and could not be sure whether the man was actually Hunter Biden. Three weeks before the 2020 United States presidential election, the New York Post published a front-page story that presented emails from the laptop, alleging they showed corruption by Joe Biden, the Democratic presidential nominee and Hunter Biden's father. According to the Post, the story was based on information provided to Rudy Giuliani, the personal attorney of incumbent president and candidate Donald Trump, by Mac Isaac. Forensic analysis later authenticated some of the emails from the laptop, including both emails used by the Post in their initial reporting. Shortly after the Post story broke, social media companies blocked links to it, while other news outlets declined to publish the story due to concerns about provenance and suspicions of Russian disinformation. On October 19, 2020, an open letter signed by 51 former US intelligence officials warned that the laptop "has all the classic earmarks of a Russian information operation." By May 2023, no evidence had publicly surfaced to support suspicions that the laptop was part of a Russian disinformation scheme. In December 2019, under the authority of a subpoena issued by a Wilmington grand jury, the FBI seized the laptop from Mac Isaac. FBI investigators handling Hunter Biden's laptop quickly concluded in 2019 "that the laptop was genuinely his and did not seem to have been tampered with or manipulated". In June 2024, federal prosecutors utilized the laptop as evidence as part of a criminal case against Hunter Biden, alongside testimony from an FBI agent involved in authenticating and investigating the laptop. The hard drive data had been shared with Trump advisor Steve Bannon before it became publicly known. Trump attempted to turn the story into an October surprise to hurt Joe Biden's campaign by falsely alleging that, while in office, Biden had acted corruptly regarding Ukraine to protect his son. A joint investigation by two Republican Senate committees released in September 2020 and a Republican House Oversight committee investigation released in April 2024 did not find wrongdoing by Joe Biden with regard to Ukraine and his son's business dealings there. PolitiFact wrote in June 2021 that the laptop did belong to Hunter Biden, but did not demonstrate wrongdoing by Joe Biden. Starting in 2021, news outlets began to authenticate some of the contents of the laptop. In 2021, Politico verified two key emails used in the Post's initial reporting by cross-referencing emails with other datasets and contacting their recipients. CBS News published a forensic analysis which examined a "clean" copy of the data obtained directly from Mac Isaac. It concluded that the "clean" data, including over 120,000 emails, originated with Hunter Biden and had not been altered, while other copies circulated by Republican operatives "could have been tampered with". Other outlets also verified portions of the data, while noting problems in fully authenticating the copies they had to work with. Background The media coverage of the laptop spurred speculation about the Biden–Ukraine conspiracy theory, which falsely alleged that then vice president Joe Biden acted in Ukraine to protect his son from a corruption investigation by Ukrainian Prosecutor General Viktor Shokin. On October 14, 2020, the New York Post published an article based on an email from the laptop about a purported meeting between then vice president Joe Biden and the Burisma advisor Vadym Pozharskyi. The Biden campaign denied Joe Biden had any meeting with Pozharskyi and said that if they had ever met, it would have been a brief encounter. Witnesses at the dinner where they allegedly met said Joe Biden briefly passed by to see an old friend. The Post reported in its story that Pozharskyi declined to comment, and he did not comment to a Politico journalist who reported extensively on the story a year later. The Post reported that the email was found in a cache of data extracted from the external hard drive of a laptop computer that belonged to Hunter Biden. The Post reported that the repair shop owner had made a copy of the external hard drive before it was seized by the US Federal Bureau of Investigation (FBI) and that the copy was later provided to the Post by Donald Trump's attorney, Rudy Giuliani. The subpoena to seize the laptop was issued by a grand jury on behalf of the US attorney's office in Wilmington, which was later reported to have been investigating Hunter Biden about lobbying and financial matters since at least 2018. The veracity of the Post's reporting was strongly questioned by many mainstream media outlets and analysts due to the initially unclear origin and chain of custody of the laptop and the provenance of its contents. Due to prior Russian influence campaigns during the 2016 election, particularly the release of documents obtained by Russian cyber attacks targeting John Podesta and the Democratic National Committee, media outlets and intelligence officials also became suspicious of a possible disinformation campaign by Russian intelligence or its proxies. Analysts also suspected Russian involvement in the 2017 leaks of emails involving French president Emmanuel Macron two days before national elections, which contained fake emails mingled with genuine ones. Adding to concerns, Giuliani had met with Andrii Derkach, later confirmed to be a Russian agent, while conducting opposition research against Joe Biden in Ukraine in 2019. New York Post reporting On October 14, 2020, the New York Post published articles containing purported emails of unknown authorship which suggested that Hunter Biden provided an "opportunity" to Vadym Pozharskyi, an advisor to the board of Burisma, to meet his father, then-Vice President Joe Biden. Joe Biden stated in September 2019 that he had never spoken to his son about his foreign business dealings. His presidential campaign denied such a meeting took place and stated the New York Post had never contacted them "about the critical elements of this story". Michael Carpenter, Vice President Biden's foreign policy adviser in 2015, told The Washington Post that he had accompanied Joe Biden during all of his meetings about Ukraine: "He never met with [Pozharskyi]. In fact, I had never heard of this guy until the New York Post story broke." One of the purported emails showed Pozharskyi saying he would share information with Amos Hochstein, a State Department advisor close to Vice President Biden, though Hochstein stated, "The Republican Senate investigation subpoenaed all my records, including emails and calendars and found no mention of this man. I led the US energy efforts in Ukraine and never even heard of him before yesterday." According to an investigation by The New York Times, editors at the New York Post "pressed staff members to add their bylines to the story", and at least one refused, in addition to the original author, reportedly because of a lack of confidence in its credibility. Of the two writers eventually credited on the article, the second did not know her name was attached to it until after The Post published it. In its opening sentence, the New York Post story misleadingly asserted, "the elder Biden pressured government officials in Ukraine into firing a prosecutor who was investigating" Burisma, even though Shokin had not pursued an investigation into Burisma's founder. The opening sentence also misleadingly stated that Hunter Biden introduced his father to Pozharskyi, but the purported email from Pozharskyi only mentioned an invitation and "opportunity" for the men to meet. On October 15, the Post published another article regarding a business venture relating to CEFC China Energy that Hunter Biden was negotiating with potential investment partners in May 2017, when his father was a private citizen. The Post published a purported email it said came from the laptop, written by one of the prospective investors, on which Hunter Biden was copied. The email described the proposed equity shares of each of the investors in the venture, ending with a reference to "10 held by H for the big guy?" The Post reported the "H" apparently referred to Hunter Biden, and one of his former business partners soon came forward to assert "the big guy" referred to Joe Biden. The former business partner also tweeted a copy of the email addressed to him. In a subsequent email, Hunter Biden said his "Chairman" gave him "an emphatic no", with a later email identifying the "chairman" as his father. The Post also reported on an August 2017 venture Hunter Biden was seeking with Ye Jianming, the chairman of CEFC, but the paper did not associate Joe Biden with that deal. Neither of the two ventures came to fruition. On May 26, 2021, the New York Post published another article focused on purported emails, suggesting that Joe Biden had met with Vadym Pozharskyi at a dinner in Cafe Milano in Washington. The Washington Post investigated the April 16, 2015, dinner. According to dinner attendee Rick Leach, who like Hunter Biden was one of the leaders of the World Food Program USA fundraising organization, the discussions at the dinner were about food security, not "politics or business". Leach said that Joe Biden briefly dropped by the dinner to meet Alex Karloutsos. According to Leach, Joe Biden "didn't even sit down. He was not part of the dinner or part of the dinner discussion." Karloutsos, a longtime friend of Joe Biden, had an influential role in the Greek Orthodox Church that Joe Biden long worked with. Karloutsos corroborated Leach's account. Also, according to The Washington Post, the tentative guest list for the dinner included the name "Vadym" with no surname listed. Rudy Giuliani provided the materials to the New York Post after they were allegedly found on a water-damaged MacBook Pro left at The Mac Shop, a Wilmington, Delaware, computer repair business owned by John Paul Mac Isaac. Mac Isaac obtained the laptop in April 2019, claiming it had been dropped off by a man who identified himself as Hunter Biden and requested that the data on the damaged laptop be recovered. Mac Isaac also said that he is legally blind and could not be sure if the person who supposedly left the laptop was actually Hunter Biden. Mac Isaac eventually brought the laptop to the attention of the FBI, who seized it in December 2019, under the authority of a subpoena issued by a Wilmington grand jury that had been investigating Hunter Biden for financial matters since 2018. He asserted three years later that while he was copying individual files and folders from the laptop's hard drive to another device, he "saw some content that was disturbing and then also raised some red flags", including "criminality ... related to foreign business dealings, to potential money laundering and, more importantly, national security issues and concerns". This caused him "to do a deep dive into the laptop once it became my property". Mac Isaac contacted Giuliani, who he said was his "lifeguard"—voicing credence to the conspiracy theory that the Hillary Clinton 2016 presidential campaign was behind the murder of campaign worker Seth Rich. Steve Bannon informed the New York Post of the laptop, and he and Giuliani delivered a copy of the supposed laptop hard drive to the publication. Weeks before, on September 28, Bannon had stated on Dutch television that he had Hunter Biden's hard drive, though this footage was not released until after the New York Post story released. Giuliani was later quoted as saying he had given the copy to the New York Post because "either nobody else would take it, or if they took it, they would spend all the time they could to try to contradict it before they put it out". According to the New York Post story, a person—who Mac Isaac could not identify because he is legally blind—left the computer at the repair shop to repair water damage, but once this was completed, the shop had no contact information for its owner, and nobody ever paid for it or came to pick it up. Criticism focused on Mac Isaac over inconsistencies in his accounts of how the laptop came into his possession and how he passed it on to Giuliani and the FBI. When interviewed by CBS News, Mac Isaac offered contradictory statements about his motivations. Thomas Rid, a political scientist and disinformation expert at Johns Hopkins University, noted that the emails could have been forged or that forged material could have been mixed with genuine materials, a "common feature" of disinformation operations. The Daily Beast reported that according to two "individuals with direct knowledge", multiple senior officials in the Trump administration and re-election campaign were aware of the laptop hard drive "several weeks" prior to the New York Post story. Giuliani later confirmed to The Daily Beast that he had informed Trump about the material before the New York Post story. The New York Post reported it had been shown an image purporting to show a federal subpoena that resulted in the computer and an external hard drive being seized by the FBI in December 2019. NBC News reported the FBI had acquired the devices via a grand jury subpoena, though it was unclear if this was the subpoena cited by the New York Post, and was investigating whether the contents were linked to a foreign intelligence operation. The Associated Press confirmed the existence of the FBI investigation into possible foreign-intelligence activity. Citing a "US official and a congressional source briefed on the matter", CNN reported the FBI was specifically investigating possible connections to ongoing Russian disinformation efforts against Joe Biden. In 2022, Mark Zuckerberg stated that an FBI warning about a possible Russian disinformation campaign prompted Facebook to remove content purporting to convey facts concerning the laptop story. According to The Washington Post, Mac Isaac was alarmed that the laptop was not mentioned during Trump's first impeachment trial in early 2020. PolitiFact wrote in June 2021: "Over time, there has been less doubt that the laptop did in fact belong to Hunter Biden", concluding that the laptop "was real in the sense that it exists, but it didn't prove much", as "Nothing from the laptop has revealed illegal or unethical behavior by Joe Biden as vice president with regard to his son's tenure as a director for Burisma". PolitiFact states that it is possible that "copies of a laptop" were obtained, instead of the actual laptop. PolitiFact states that the Daily Mail published nude photos of Hunter Biden from the laptop, as well as other content focused on Hunter Biden's drug use and legal issues, but notes that Hunter Biden had already publicized his drug issues. Material similar to the alleged hard-drive contents was reportedly circulating in Ukraine in 2019. One individual interviewed by Time magazine stated that he had been approached in late May 2019, and a second person stated that he had been approached in mid-September. According to the second individual, the seller wished to sell compromising information about Hunter Biden to Republican Party allies of Donald Trump for $5 million. "I walked away from it, because it smelled awful", he told Time. Igor Novikov, a former advisor to the Ukrainian president and a disinformation researcher, said that the market for kompromat (damaging material) had been very active in the past year in reaction to political events in the United States, with political operatives rushing to respond to Giuliani's call for damaging information on the Bidens. Novikov characterized the materials available on the market as "extremely hard to verify, yet very easy to fake". Ukrainian legislator Andrii Derkach, an active Russian agent, worked with Giuliani in Ukraine to damage Biden. Derkach said Giuliani was "very useful for me". They met during multiple meetings leading up to the 2020 election. Derkach attempted to shift blame for election interference in the 2020 election from Russia to Ukraine, and claimed that Ukraine was trying to get Biden elected. On October 19, 2020, Derkach posted on social media that he had a second Hunter Biden laptop: "The facts confirming international corruption are stored on a second laptop. These are not the last witnesses or the last laptop." Derkach was later sanctioned by the United States Treasury Department for his involvement in disinformation about Joe Biden; the Treasury concluded Derkach had been an active Russian intelligence agent for over a decade; the Security Service of Ukraine (SBU) have also said that Derkach received funds from the Russian GRU, and initiated an investigation into his role. Lev Parnas told Politico that Giuliani had been told about compromising material regarding Hunter Biden on May 30, 2019, during a visit with Vitaly Pruss. Pruss was an associate of Burisma founder Mykola Zlochevsky, who was then being investigated for corruption by Ukraine. Earlier in October, before the Post's report, White House lawyer Eric Herschmann, former deputy White House counsel Stefan Passantino, former Hunter Biden business partner Tony Bobulinski, and close Donald Trump Jr. associate Arthur Schwartz pitched a story about Hunter Biden's business dealings in China to The Wall Street Journal, which the Trump team saw as an ideal outlet due to its combination of conservatism and industry credibility. Without warning to the Trump team and while the Journal was exercising due diligence in investigating the story, the New York Post went ahead and published a version of the story based on documents and emails with "questionable provenance" that alleged, but did not prove, Joe Biden's involvement in his son's affairs. Bannon had anticipated the Journal story would appear on October 19, and Trump told reporters to expect a major story in the Journal. Bobulinski thought it would not run the piece, so he issued his own statement on October 21, which Breitbart News published unedited. During the next day's presidential debate, Trump vaguely referred to the emails and Bobulinski was his special guest. Afterward, the Journal published a brief story saying corporate records it reviewed "show no role for Joe Biden". The New York Times reported in May 2021 that federal investigators in Brooklyn had begun a criminal investigation late in the Trump administration into possible efforts by several current and former Ukrainian officials to spread unsubstantiated allegations about Joe Biden concerning corruption. The investigators had been examining whether the Ukrainians used Giuliani as a channel for the allegations, though he was not a specific subject of the investigation, in contrast to a long-running investigation of Giuliani by the US attorney's office in Manhattan. The New York Times reported in March 2022 that they found emails "from a cache of files that appears to have come from a laptop abandoned by Mr. Biden in a Delaware repair shop". In March 2022, Vox reported that no evidence had ever emerged "that the laptop's leak was a Russian plot". That month, The New York Times reported that sources familiar with the emails and an investigation of Hunter Biden related to possible financial impropriety said some emails between Hunter Biden, his business partner and others regarding Burisma and other foreign business activity had been authenticated. Emails showed Hunter Biden and his business partner discussed inviting foreign business associates to the April 2015 dinner in Washington, including Pozharskyi. In April 2022, The Washington Post reported that Mac Isaac said that he had seen claims about what the laptop contained that did not reflect what he had seen on the laptop: "I do know that there have been multiple attempts over the past year-and-a-half to insert questionable material into the laptop as in, not physically, but passing off this misinformation or disinformation as coming from the laptop. And that is a major concern of mine because I have fought tooth and nail to protect the integrity of this drive and to jeopardize that is going to mean that everything that I sacrificed will be for nothing." In May 2022, NBC News published an analysis of a copy of the hard drive they received from Giuliani and documents released by Republicans on two Senate committees. The analysis found that Hunter Biden's firm took in $11 million from 2013 to 2018 and spent the money quickly. The analysis also found that few of Hunter Biden's deals ever came to fruition. Classified materials were found in the home and former office of president Joe Biden in late 2022 and early 2023. Following this development, some Republicans and conservative commentators sought to cite materials found on the laptop to suggest improper activity by the Bidens, relating to classified information and possible corruption. In one case, an email from the laptop that Hunter Biden apparently sent to his business partner as they prepared to work for Burisma in April 2014 came under the scrutiny of Fox News, and senators Ron Johnson and Ted Cruz. In their view, the email contents of geopolitical analysis read as though it contained information from classified sources. Glenn Kessler, a Washington Post fact checker, found the email content to be a close match with contemporaneous newspaper and magazine reporting. In another case, in January 2023 an anonymous Twitter account posted a rental application found on the laptop, leading to a false claim that in 2018 Hunter Biden had paid $49,910 in monthly rent for his father's Delaware residence where classified documents had been found. The false allegation quickly spread across conservative media. A Breitbart story that speculated Hunter Biden may have had access to classified documents in his father's home was retweeted by House Republican Conference chair Elise Stefanik who added that "Joe Biden and the Biden Crime Family are corrupt and significant threats to national security. Our Republican House Majority will hold them accountable." James Comer, chair of the House Oversight Committee that was investigating the Biden family, suggested it was evidence that Hunter Biden may have been funneling foreign money to his father. The document actually showed quarterly rental payments for office space at the House of Sweden in Washington, D.C. On his Fox News program, host Tucker Carlson echoed Comer's false suggestion of Hunter Biden malfeasance; days later Hunter Biden's attorneys wrote Carlson and Fox News demanding they correct the falsehood on-air or risk a defamation lawsuit. Forensic analysis In March 2022, The Washington Post published the findings of two forensic information analysts it had retained to examine 217 gigabytes of data provided to the paper on a hard drive by Republican activist Jack Maxey, who represented that its contents came from the laptop. One of the analysts characterized the data as a "disaster" from a forensics standpoint. The analysts found that people other than Hunter Biden had repeatedly accessed and copied data for nearly three years; they also found evidence that people other than Hunter Biden had accessed and written files to the drive, both before and after the New York Post story. In September 2020, someone created six new folders on the drive, including some with the names "Biden Burisma", "Big Guy File", "Salacious Pics Package" and "Hunter. Burisma Documents". One of the analysts found evidence someone may have accessed the drive contents from a West Coast location days after The New York Post published their stories about the laptop. Using cryptographic signatures, one analyst verified that 1,828 of the roughly 129,000 emails on the drive came from the indicated email accounts of origin, suggesting they were authentic and had not been tampered with. The other analysis verified nearly 22,000 emails using similar methods, after overcoming technical issues the first analysis could not resolve. The analysts said emails from Burisma, where Pozharskyi was an advisor, were likely authentic but cautioned that if Burisma had been hacked, it would be possible for hackers to use stolen cryptographic signatures to forge emails that would pass as authentic. The New York Times reported in January 2020 that Russian military intelligence had hacked Burisma beginning in November 2019; a co-founder of the firm that discovered the hacking said Russians were stealing email credentials. Both analysts acknowledged that cryptographic signatures are not a perfect way to authenticate emails, as some email services do not implement the technology as rigorously as others. About 16,000 of the 22,000 emails carrying cryptographic signatures came via Google, which rigorously implements the technology. The analysts noted that cryptographic signatures can only verify that an email originated from a certain email account, but not who controlled that account; there are other means for hackers to commandeer email accounts. According to the Washington Post, "Some other emails on the drive that have been the foundation for previous news reports could not be verified because the messages lacked verifiable cryptographic signatures." Among the emails that The Washington Post was able to authenticate was the Pozharskyi email that formed the basis of the New York Post's original article. An email referencing "10 held by H for the big guy?", a possible reference to a rejected proposal to give Joe Biden a 10% share of a Chinese deal his son was negotiating, was not authenticated, though a recipient of the email publicly vouched for its authenticity. One of the analysts found that timestamps on documents and operating system indexes matched, though he noted hackers could forge timestamps in undetectable ways. The analysts also noted that repeated access to the drive resulted in logs and other files used by forensic analysts to examine system activity being deleted. Neither analyst found evidence emails or other files had been manipulated by hackers, nor could they rule out that possibility. In reference to a cache of emails allegedly coming from the Hunter Biden Laptop, Matt Tait, a former information security specialist for the GCHQ (UK's Government Communications Headquarters), told CyberScoop, "it is clear the cache isn't in its original form". In November 2022, CBS News published the results of a forensic analysis they commissioned of a copy of the laptop data Mac Isaac initially handed to federal investigators in 2019. The analysis, conducted by Computer Forensics Services, found data, including over 120,000 emails, "consistent with normal, everyday use of a computer", found "no evidence that the user data had been modified, fabricated or tampered with", and found no new files created on the laptop after April 2019, when Mac Isaac received the laptop. The chief technology officer of Computer Forensics Services added: "I have no doubt in my mind that this data was created by Hunter Biden, and that it came from a computer under Mr. Biden's control". Also on November 21, CBS News published the first photograph of the damaged Macbook Pro, which had been provided to them by Hunter Biden's legal team. According to reports on January 16, 2024, new filings by the U.S. Department of Justice's special counsel, headed by David C. Weiss, appear to be the first public confirmation of the laptop's authenticity by the DOJ. The filings refer to the laptop connected to Hunter Biden stating, "the defendant's Apple MacBook Pro, which he had left at a computer store." Lawsuits In December 2020, Mac Isaac sued Twitter for defamation over their handling of the New York Post story, claiming that their decision to remove the article under their "hacked materials" policy falsely tarred him as a hacker. The case was dismissed within a day of its filing based on jurisdictional grounds. Mac Isaac then filed a second suit against the company. Florida district judge Beth Bloom dismissed the second lawsuit with prejudice in September 2021, noting that Twitter never mentioned Mac Isaac or his business, and ordered Mac Isaac to pay Twitter's attorney fees under Florida's anti-SLAPP statute. In May 2022, Mac Isaac again sued a number of individuals and publications for defamation, alleging that he had suffered reputational damage over claims that the laptop story had been part of a Russian disinformation campaign and that he had illegally accessed the data on the laptop. The suit named Hunter Biden, Democratic representative Adam Schiff, and the news publications CNN, Politico, and The Daily Beast. Schiff stated in an October 2020 interview with Wolf Blitzer in CNN that “Well we know that this whole smear on Joe Biden comes from the Kremlin. That’s been clear for well over a year now that they’ve been pushing this false narrative about the Vice President and his son." In March 2023, Hunter Biden countersued Mac Isaac, responding to his defamation suit and alleging that Mac Isaac had invaded his privacy and had no legal right to copy and distribute his private information. The suit lists six counts of invasion of privacy by Mac Isaac and others, and seeks a jury trial to determine compensatory and punitive damages. On September 30, 2024, Delaware Superior Court Judge Robert Robinson Jr. dismissed both Mac Isaac's defamation claims, and Biden's counterclaims. One of Mac Isaac's lawyers said that he planned to appeal the decision. In September 2023, Hunter Biden filed a civil lawsuit against Giuliani, his companies and attorney Robert Costello, alleging that they had spent years "hacking into, tampering with, manipulating, copying, disseminating, and generally obsessing over data that they were given that was taken or stolen from" his personal devices and caused "total annihilation" of his digital privacy. Biden agreed to drop the lawsuit in June 2024. In September 2023, Hunter Biden sued activist and former Trump staffer Garrett Ziegler for allegedly violating privacy laws through distributing Biden's data related to the laptop. Biden had previously referred Ziegler to federal and state investigators for alleged crimes. In March 2025, Biden moved to dismiss the lawsuit as he did not have the funds to continue the legal proceedings. Following this, Judge Hernán Vera dismissed the suit with prejudice. Trial on gun charges In June 2024, special counsel Weiss introduced the laptop, related files, and an invoice from Mac Isaac's repair shop as evidence in Biden's trial in Delaware, in which he was found guilty of purchasing a firearm while a recent drug user. Defense attorneys for Biden argued that they had "numerous reasons to believe the data had been altered and compromised before investigators obtained the electronic material", which Weiss described as "a conspiracy theory with no supporting evidence". Prosecutors stated that defense attorneys had not "provided any evidence or information that shows that his laptop contains false information". The presiding judge sided with prosecutors. On June 4, 2024, the laptop was introduced into evidence by the prosecution. An FBI witness testified that the FBI had Biden's original laptop. She further testified about Biden's texts, his 2021 autobiography which detailed his drug addiction, and his bank records. Reactions During an April 2021 interview with CBS correspondent Tracy Smith, when asked if the laptop was his, Hunter Biden replied that he did not know and did not remember dropping off a laptop in Delaware for repairs, adding: "There could be a laptop out there that was stolen from me. It could be that I was hacked. It could be that it was Russian intelligence. It could be that it was stolen from me." In May 2021, Hunter enlisted the counsel of lawyer Kevin Morris to investigate the circumstances of the laptop's release to the press. On October 19, 2020, a group of 51 former senior intelligence officials, who had served in the Trump administration and those of the three previous presidents, released an open letter stating that the release of the alleged emails "has all the classic earmarks of a Russian information operation", adding: We want to emphasize that we do not know if the emails, provided to the New York Post by President Trump's personal attorney Rudy Giuliani, are genuine or not and that we do not have evidence of Russian involvement—just that our experience makes us deeply suspicious that the Russian government played a significant role in this case. That night, Natasha Bertrand of Politico wrote a story about the letter, with the headline, "Hunter Biden story is Russian disinfo, dozens of former intel officials say." The rest of the story, however, was less definitive, with a subheading saying the former officials "signed a letter casting doubt on the provenance of a New York Post story," and noting in the story body that the letter said the information in the Post story "has all the classic earmarks of a Russian information operation." In a February 2023 analysis, Washington Post fact checker Glenn Kessler wrote "that headline likely shaped perceptions of the letter that continue to this day." Former director of national intelligence James Clapper, who signed the letter, told Kessler, "There was message distortion. All we were doing was raising a yellow flag that this could be Russian disinformation. Politico deliberately distorted what we said. It was clear in paragraph five" of the letter. Politico stood by their report in a statement to Kessler. In the final presidential debate for 2020 and in an interview with 60 Minutes, Joe Biden referenced the letter from the intelligence officials. He inaccurately claimed the letter asserted that the laptop controversy was a "Russian plan", "a bunch of garbage", "disinformation from the Russians" and "a smear campaign". During an interview with Fox News on October 19, 2020, National Intelligence Director John Ratcliffe said the laptop was "not part of some Russian disinformation campaign" and accused Adam Schiff of mischaracterizing the views of the intelligence community by describing the alleged emails as part of a smear campaign against Biden. Schiff's spokesman accused Ratcliffe of "purposefully misrepresenting" the US representative's words. Ratcliffe had previously made public assertions that contradicted professional intelligence assessments. Several security officials criticized Ratcliffe for appearing to pre-judge its outcome. The FBI said it had "nothing to add" to Ratcliffe's remarks in response to a request for more information made by Sen. Ron Johnson. The New York Times reported days after the Post story that no solid evidence had emerged that the laptop contained Russian disinformation. On January 20, 2025, Donald Trump issued an executive order revoking the security clearances of all the officials who signed the letter. The executive order states "The signatories willfully weaponized the gravitas of the Intelligence Community to manipulate the political process and undermine our democratic institutions". Lawyers including Mark Zaid and Dan Meyer said that the revocation can be challenged in court. After the 2016 election, social media companies were criticized for allowing false political information to proliferate on their platforms, including disinformation from Russian intelligence, suggesting it may have assisted Trump's election. In October 2020, both Twitter and Facebook implemented measures on their platforms to prevent sharing of the New York Post article. Twitter first deprecated the story (prevented its algorithm from highlighting it due to its popularity) but eventually banned links to the story from being posted. It did so according to its Hacked Materials Policy and Facebook per a policy that "in many countries, including in the US, if we have signals that a piece of content is false, we temporarily reduce its distribution pending review by a third-party fact-checker". Facebook's decision had been informed by an FBI warning to watch for disinformation spread by foreign actors. The Hill reported on the Facebook action, "it is unclear what "signals" triggered the limit on the New York Post article". Twitter briefly locked Trump's presidential campaign Twitter account for sharing a controversial Hunter Biden video earlier on October 15. The account was unlocked later that day. Between October 14 and 23, the original New York Post story received over 54 million Facebook views. Commentators from varied political backgrounds criticized the actions taken by Facebook and Twitter, arguing that they could have amplified disinformation thanks to the Streisand effect. Twitter CEO Jack Dorsey added: "Our communication around our actions on the @nypost article was not great. And blocking URL sharing via tweet or DM with zero context as to why we're blocking: unacceptable." On October 14, Trump tweeted about Facebook and Twitter's actions, including a threat to repeal the safe harbor provisions of Section 230 of the Communications Decency Act, under which they operate. Congressional Republicans on the Senate Judiciary Committee called on Facebook CEO Mark Zuckerberg and Twitter CEO Jack Dorsey to testify before the committee in response to their platforms' actions. Senators Ted Cruz, Lindsey Graham, and Josh Hawley announced that the committee would vote on subpoenaing Dorsey to appear on October 23. Senate Majority Leader Mitch McConnell described the restrictions made by Facebook and Twitter as "absolutely reprehensible" and stated that the companies were acting as "speech police". Dorsey said: "Straight blocking of URLs was wrong, and we updated our policy and enforcement to fix. Our goal is to attempt to add context, and now we have capabilities to do that." In March 2021, Dorsey told Congress: "It was literally just a process error. This was not against them [the Post] in any particular way." Facebook also said that it was restricting spread pending input from third-party fact-checkers. Associated Press noted that the story had, as of October 17, 2020, "not been confirmed by other publications". In an August 2022 Mark Zuckerberg interview on the Joe Rogan podcast, Zuckerberg said that Facebook thought the story fit the pattern of Russian propaganda and called it a "hyper-political issue". Zuckerberg also said that the FBI had previously told Facebook to be aware of potential propaganda about the 2020 presidential election and was told by them that "there's about to be some kind of dump". When the New York Post story was published, Facebook thought that it "fit that pattern" the FBI told Facebook about. In October 2022, The Intercept reported that records filed in federal court as part of a lawsuit revealed that two FBI agents were involved in communications with Facebook that allegedly "led to Facebook's suppression" of the New York Post story, although The Intercept also noted that the lawsuit has a "partisan slant". Biden administration attorneys responded by saying that the plaintiffs related to the lawsuit lacked standing and that social media companies pursued content moderation policies on their own without "coercive" influence from the US government. The New York Times reported in September 2021 that a Federal Election Commission inquiry into a complaint about Twitter's exclusion of the article had dismissed the complaint, saying the social media company had legitimate commercial reasons for its actions and that it could not be determined that Twitter had acted on purely political grounds. Ross Douthat pointed out similarities between social media reactions to the Hunter-Biden-laptop-and-emails situation and the Steele dossier. He did not see the New York Post story as Russian disinformation but "a more normal example of late-dropping opposition research, filtered through a partisan lens and a tabloid sensibility, weaving genuine facts into contestable conclusions. It was, in other words, analogous to all kinds of contested anti-Trump stories that various media outlets have run with across the last four crazy years—from the publicity around the Steele dossier's wilder rumors to the tales of Michael Cohen's supposed Prague rendezvous to the claims that Russians hacked Vermont's power grid or even C-SPAN." Ben Smith, who felt that social media should have treated the laptop and dossier stories in the same way, described how he published the dossier for BuzzFeed News in 2017 when he saw that media gatekeepers were "keeping [the dossier] from their audience". He saw the media's refusal to cover the laptop as a "revenge of the gatekeepers". The Hunter Biden laptop story resulted in increased scrutiny of Twitter's and Facebook's actions in supposedly limiting the dissemination of the story by conservatives; in an editorial, conservative news outlet The Washington Examiner wrote: "What is needed, not just on the laptop story but in general, is a major course correction by Big Tech. These companies need more humility about their own biases and their lack of expertise in distinguishing truth from fiction." In December 2022, Twitter owner Elon Musk gave several writers access to internal company documents from October 2020 that showed Twitter executives' discussion of its content moderation relating to the Post story. Musk and others asserted Twitter had been ordered by the government to help Joe Biden in the coming election by suppressing the Post laptop story. Journalist Matt Taibbi, one of those given access for the Twitter Files examination, found no evidence of government involvement in Twitter's decision to initially withhold the story. Taibbi wrote: 22. Although several sources recalled hearing about a 'general' warning from federal law enforcement that summer about possible foreign hacks, there's no evidence - that I've seen - of any government involvement in the laptop story. In fact, that might have been the problem... Republican House members Jim Jordan and James Comer launched complementary investigations in January 2023. Former Twitter employees and members of the Twitter Files team provided testimony. Both committees concluded their investigations in 2024. In June 2024, the Supreme Court rejected claims that the government unlawfully coerced social media companies into removing posts related to the laptop in Murthy v. Missouri. Justice Amy Coney Barrett, in her majority opinion, wrote that while government agencies "played a role" in moderation choices, social media companies had acted independently to strengthen moderation policies prior to any government involvement. Justice Barrett stated that there was a lack of evidence to demonstrate that content moderation decisions could be traced back to actions taken by the FBI or the Cybersecurity and Infrastructure Security Agency. The Joe Biden 2020 presidential campaign press secretary Jamal Brown stated that Twitter's action concerning the New York Post story indicated that the allegations in the story were false. Brown specifically denied that Joe Biden ever had a formal meeting with Pozharskyi, and said that if they had ever met, it would have been a brief encounter. On January 21, 2021, the day after Biden's inauguration, Republican representative Marjorie Taylor Greene of Georgia filed an article of impeachment, which made a reference to the laptop. No fellow members of Congress co-sponsored the article. The New York Times, The Washington Post and The Wall Street Journal stated that they could not independently verify the data provided by the New York Post. NBC News requested a copy of the hard drive from Giuliani, who said he would not provide one and offered it copies of a small portion of emails instead. In May 2022, NBC News published an analysis of a copy of the hard drive they received from Giuliani and documents released by Republicans on two Senate committees. The analysis found that Hunter Biden's firm took in $11 million from 2013 to 2018 and spent the money fast. The analysis also found that few of Hunter Biden's deals ever came to fruition. In 2020, David Folkenflik of NPR observed that the New York Post story asserted as facts things it presumed to be true. He also noted that the credited lead author of the story, deputy political editor Emma-Jo Morris, had virtually no previous bylines in reporting. Her most significant prior employment was a nearly four-year position as a producer on Sean Hannity's Fox News program. Hannity, a close Trump advisor, had repeatedly suggested wrongdoing by Biden in Ukraine. During a House subcommittee hearing held by the Department of Government Efficiency in 2025 titled "Anti-American Airwaves: Holding the Heads of NPR and PBS Accountable," NPR CEO Katherine Maher responded to concerns of bias, saying that NPR abides by journalistic standards while serving a diverse audience, and that "NPR acknowledges that we were mistaken and failing to cover the Hunter Biden laptop story more aggressively and sooner," Vanity Fair observed the story had exposed an ongoing journalistic "cold war" within Rupert Murdoch's media empire, which includes The New York Post, Fox News, and The Wall Street Journal. In particular, it described an internal rift over coverage by the Journal, which published an opinion article by conservative columnist Kimberley Strassel inflating the claims, before running a news article which "swept the legs out from under their Opinion colleague's argument" four hours later. Ryan Lizza of Politico wrote: "Reporters at the WSJ, Fox News, and NYP have all come to the same conclusion about these documents but they are being drowned out by bad faith activists on the opinion side at these Murdoch companies who favor Trump's re-election." In April 2022, the editorial board of The Washington Post gave its opinion about a report published by the Post that month: The investigation adds new details and confirms old ones about the ways in which Joe Biden's family has profited from trading overseas on his name—something for which the president deserves criticism for tacitly condoning. What it does not do, despite some conservatives' insistence otherwise, is prove that President Biden acted corruptly. Joan Donovan, the research director of the Shorenstein Center on Media, Politics, and Public Policy at Harvard University, wrote: "This is arguably the most well-known story the New York Post has ever published and it endures as a story because it was initially suppressed by social media companies and jeered by politicians and pundits alike." Former Politico reporters Marc Caputo and Tara Palmeri said in January 2025 that, because of "dumb decisions of cowardly editors", they were told "Don't write about the laptop, don't talk about the laptop, don't tweet about the laptop". Caputo said the Bertrand story about the 51 former officials had a "terrible, ill-fated headline ... because the Hunter Biden laptop appeared to be true". In 2019 the campaign of a rival Democratic candidate for the 2020 presidential election gave Caputo opposition research on Burisma and Hunter Biden but "That story was killed by the editors, and they gave no explanation for that either", he recalled. See also References External links |
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Contents Elon Musk Elon Reeve Musk (/ˈiːlɒn/ EE-lon; born June 28, 1971) is a businessman and entrepreneur known for his leadership of Tesla, SpaceX, Twitter, and xAI. Musk has been the wealthiest person in the world since 2025; as of February 2026,[update] Forbes estimates his net worth to be around US$852 billion. Born into a wealthy family in Pretoria, South Africa, Musk emigrated in 1989 to Canada; he has Canadian citizenship since his mother was born there. He received bachelor's degrees in 1997 from the University of Pennsylvania before moving to California to pursue business ventures. In 1995, Musk co-founded the software company Zip2. Following its sale in 1999, he co-founded X.com, an online payment company that later merged to form PayPal, which was acquired by eBay in 2002. Musk also became an American citizen in 2002. In 2002, Musk founded the space technology company SpaceX, becoming its CEO and chief engineer; the company has since led innovations in reusable rockets and commercial spaceflight. Musk joined the automaker Tesla as an early investor in 2004 and became its CEO and product architect in 2008; it has since become a leader in electric vehicles. In 2015, he co-founded OpenAI to advance artificial intelligence (AI) research, but later left; growing discontent with the organization's direction and their leadership in the AI boom in the 2020s led him to establish xAI, which became a subsidiary of SpaceX in 2026. In 2022, he acquired the social network Twitter, implementing significant changes, and rebranding it as X in 2023. His other businesses include the neurotechnology company Neuralink, which he co-founded in 2016, and the tunneling company the Boring Company, which he founded in 2017. In November 2025, a Tesla pay package worth $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Musk was the largest donor in the 2024 U.S. presidential election, where he supported Donald Trump. After Trump was inaugurated as president in early 2025, Musk served as Senior Advisor to the President and as the de facto head of the Department of Government Efficiency (DOGE). After a public feud with Trump, Musk left the Trump administration and returned to managing his companies. Musk is a supporter of global far-right figures, causes, and political parties. His political activities, views, and statements have made him a polarizing figure. Musk has been criticized for COVID-19 misinformation, promoting conspiracy theories, and affirming antisemitic, racist, and transphobic comments. His acquisition of Twitter was controversial due to a subsequent increase in hate speech and the spread of misinformation on the service, following his pledge to decrease censorship. His role in the second Trump administration attracted public backlash, particularly in response to DOGE. The emails he sent to Jeffrey Epstein are included in the Epstein files, which were published between 2025–26 and became a topic of worldwide debate. Early life Elon Reeve Musk was born on June 28, 1971, in Pretoria, South Africa's administrative capital. He is of British and Pennsylvania Dutch ancestry. His mother, Maye (née Haldeman), is a model and dietitian born in Saskatchewan, Canada, and raised in South Africa. Musk therefore holds both South African and Canadian citizenship from birth. His father, Errol Musk, is a South African electromechanical engineer, pilot, sailor, consultant, emerald dealer, and property developer, who partly owned a rental lodge at Timbavati Private Nature Reserve. His maternal grandfather, Joshua N. Haldeman, who died in a plane crash when Elon was a toddler, was an American-born Canadian chiropractor, aviator and political activist in the technocracy movement who moved to South Africa in 1950. Elon has a younger brother, Kimbal, a younger sister, Tosca, and four paternal half-siblings. Musk was baptized as a child in the Anglican Church of Southern Africa. Despite both Elon and Errol previously stating that Errol was a part owner of a Zambian emerald mine, in 2023, Errol recounted that the deal he made was to receive "a portion of the emeralds produced at three small mines". Errol was elected to the Pretoria City Council as a representative of the anti-apartheid Progressive Party and has said that his children shared their father's dislike of apartheid. After his parents divorced in 1979, Elon, aged around 9, chose to live with his father because Errol Musk had an Encyclopædia Britannica and a computer. Elon later regretted his decision and became estranged from his father. Elon has recounted trips to a wilderness school that he described as a "paramilitary Lord of the Flies" where "bullying was a virtue" and children were encouraged to fight over rations. In one incident, after an altercation with a fellow pupil, Elon was thrown down concrete steps and beaten severely, leading to him being hospitalized for his injuries. Elon described his father berating him after he was discharged from the hospital. Errol denied berating Elon and claimed, "The [other] boy had just lost his father to suicide, and Elon had called him stupid. Elon had a tendency to call people stupid. How could I possibly blame that child?" Elon was an enthusiastic reader of books, and had attributed his success in part to having read The Lord of the Rings, the Foundation series, and The Hitchhiker's Guide to the Galaxy. At age ten, he developed an interest in computing and video games, teaching himself how to program from the VIC-20 user manual. At age twelve, Elon sold his BASIC-based game Blastar to PC and Office Technology magazine for approximately $500 (equivalent to $1,600 in 2025). Musk attended Waterkloof House Preparatory School, Bryanston High School, and then Pretoria Boys High School, where he graduated. Musk was a decent but unexceptional student, earning a 61/100 in Afrikaans and a B on his senior math certification. Musk applied for a Canadian passport through his Canadian-born mother to avoid South Africa's mandatory military service, which would have forced him to participate in the apartheid regime, as well as to ease his path to immigration to the United States. While waiting for his application to be processed, he attended the University of Pretoria for five months. Musk arrived in Canada in June 1989, connected with a second cousin in Saskatchewan, and worked odd jobs, including at a farm and a lumber mill. In 1990, he entered Queen's University in Kingston, Ontario. Two years later, he transferred to the University of Pennsylvania, where he studied until 1995. Although Musk has said that he earned his degrees in 1995, the University of Pennsylvania did not award them until 1997 – a Bachelor of Arts in physics and a Bachelor of Science in economics from the university's Wharton School. He reportedly hosted large, ticketed house parties to help pay for tuition, and wrote a business plan for an electronic book-scanning service similar to Google Books. In 1994, Musk held two internships in Silicon Valley: one at energy storage startup Pinnacle Research Institute, which investigated electrolytic supercapacitors for energy storage, and another at Palo Alto–based startup Rocket Science Games. In 1995, he was accepted to a graduate program in materials science at Stanford University, but did not enroll. Musk decided to join the Internet boom of the 1990s, applying for a job at Netscape, to which he reportedly never received a response. The Washington Post reported that Musk lacked legal authorization to remain and work in the United States after failing to enroll at Stanford. In response, Musk said he was allowed to work at that time and that his student visa transitioned to an H1-B. According to numerous former business associates and shareholders, Musk said he was on a student visa at the time. Business career In 1995, Musk, his brother Kimbal, and Greg Kouri founded the web software company Zip2 with funding from a group of angel investors. They housed the venture at a small rented office in Palo Alto. Replying to Rolling Stone, Musk denounced the notion that they started their company with funds borrowed from Errol Musk, but in a tweet, he recognized that his father contributed 10% of a later funding round. The company developed and marketed an Internet city guide for the newspaper publishing industry, with maps, directions, and yellow pages. According to Musk, "The website was up during the day and I was coding it at night, seven days a week, all the time." To impress investors, Musk built a large plastic structure around a standard computer to create the impression that Zip2 was powered by a small supercomputer. The Musk brothers obtained contracts with The New York Times and the Chicago Tribune, and persuaded the board of directors to abandon plans for a merger with CitySearch. Musk's attempts to become CEO were thwarted by the board. Compaq acquired Zip2 for $307 million in cash in February 1999 (equivalent to $590,000,000 in 2025), and Musk received $22 million (equivalent to $43,000,000 in 2025) for his 7-percent share. In 1999, Musk co-founded X.com, an online financial services and e-mail payment company. The startup was one of the first federally insured online banks, and, in its initial months of operation, over 200,000 customers joined the service. The company's investors regarded Musk as inexperienced and replaced him with Intuit CEO Bill Harris by the end of the year. The following year, X.com merged with online bank Confinity to avoid competition. Founded by Max Levchin and Peter Thiel, Confinity had its own money-transfer service, PayPal, which was more popular than X.com's service. Within the merged company, Musk returned as CEO. Musk's preference for Microsoft software over Unix created a rift in the company and caused Thiel to resign. Due to resulting technological issues and lack of a cohesive business model, the board ousted Musk and replaced him with Thiel in 2000.[b] Under Thiel, the company focused on the PayPal service and was renamed PayPal in 2001. In 2002, PayPal was acquired by eBay for $1.5 billion (equivalent to $2,700,000,000 in 2025) in stock, of which Musk—the largest shareholder with 11.72% of shares—received $175.8 million (equivalent to $320,000,000 in 2025). In 2017, Musk purchased the domain X.com from PayPal for an undisclosed amount, stating that it had sentimental value. In 2001, Musk became involved with the nonprofit Mars Society and discussed funding plans to place a growth-chamber for plants on Mars. Seeking a way to launch the greenhouse payloads into space, Musk made two unsuccessful trips to Moscow to purchase intercontinental ballistic missiles (ICBMs) from Russian companies NPO Lavochkin and Kosmotras. Musk instead decided to start a company to build affordable rockets. With $100 million of his early fortune, (equivalent to $180,000,000 in 2025) Musk founded SpaceX in May 2002 and became the company's CEO and Chief Engineer. SpaceX attempted its first launch of the Falcon 1 rocket in 2006. Although the rocket failed to reach Earth orbit, it was awarded a Commercial Orbital Transportation Services program contract from NASA, then led by Mike Griffin. After two more failed attempts that nearly caused Musk to go bankrupt, SpaceX succeeded in launching the Falcon 1 into orbit in 2008. Later that year, SpaceX received a $1.6 billion NASA contract (equivalent to $2,400,000,000 in 2025) for Falcon 9-launched Dragon spacecraft flights to the International Space Station (ISS), replacing the Space Shuttle after its 2011 retirement. In 2012, the Dragon vehicle docked with the ISS, a first for a commercial spacecraft. Working towards its goal of reusable rockets, in 2015 SpaceX successfully landed the first stage of a Falcon 9 on a land platform. Later landings were achieved on autonomous spaceport drone ships, an ocean-based recovery platform. In 2018, SpaceX launched the Falcon Heavy; the inaugural mission carried Musk's personal Tesla Roadster as a dummy payload. Since 2019, SpaceX has been developing Starship, a reusable, super heavy-lift launch vehicle intended to replace the Falcon 9 and Falcon Heavy. In 2020, SpaceX launched its first crewed flight, the Demo-2, becoming the first private company to place astronauts into orbit and dock a crewed spacecraft with the ISS. In 2024, NASA awarded SpaceX an $843 million (equivalent to $865,000,000 in 2025) contract to build a spacecraft that NASA will use to deorbit the ISS at the end of its lifespan. In 2015, SpaceX began development of the Starlink constellation of low Earth orbit satellites to provide satellite Internet access. After the launch of prototype satellites in 2018, the first large constellation was deployed in May 2019. As of May 2025[update], over 7,600 Starlink satellites are operational, comprising 65% of all operational Earth satellites. The total cost of the decade-long project to design, build, and deploy the constellation was estimated by SpaceX in 2020 to be $10 billion (equivalent to $12,000,000,000 in 2025).[c] During the Russian invasion of Ukraine, Musk provided free Starlink service to Ukraine, permitting Internet access and communication at a yearly cost to SpaceX of $400 million (equivalent to $440,000,000 in 2025). However, Musk refused to block Russian state media on Starlink. In 2023, Musk denied Ukraine's request to activate Starlink over Crimea to aid an attack against the Russian navy, citing fears of a nuclear response. Tesla, Inc., originally Tesla Motors, was incorporated in July 2003 by Martin Eberhard and Marc Tarpenning. Both men played active roles in the company's early development prior to Musk's involvement. Musk led the Series A round of investment in February 2004; he invested $6.35 million (equivalent to $11,000,000 in 2025), became the majority shareholder, and joined Tesla's board of directors as chairman. Musk took an active role within the company and oversaw Roadster product design, but was not deeply involved in day-to-day business operations. Following a series of escalating conflicts in 2007 and the 2008 financial crisis, Eberhard was ousted from the firm.[page needed] Musk assumed leadership of the company as CEO and product architect in 2008. A 2009 lawsuit settlement with Eberhard designated Musk as a Tesla co-founder, along with Tarpenning and two others. Tesla began delivery of the Roadster, an electric sports car, in 2008. With sales of about 2,500 vehicles, it was the first mass production all-electric car to use lithium-ion battery cells. Under Musk, Tesla has since launched several well-selling electric vehicles, including the four-door sedan Model S (2012), the crossover Model X (2015), the mass-market sedan Model 3 (2017), the crossover Model Y (2020), and the pickup truck Cybertruck (2023). In May 2020, Musk resigned as chairman of the board as part of the settlement of a lawsuit from the SEC over him tweeting that funding had been "secured" for potentially taking Tesla private. The company has also constructed multiple lithium-ion battery and electric vehicle factories, called Gigafactories. Since its initial public offering in 2010, Tesla stock has risen significantly; it became the most valuable carmaker in summer 2020, and it entered the S&P 500 later that year. In October 2021, it reached a market capitalization of $1 trillion (equivalent to $1,200,000,000,000 in 2025), the sixth company in U.S. history to do so. Musk provided the initial concept and financial capital for SolarCity, which his cousins Lyndon and Peter Rive founded in 2006. By 2013, SolarCity was the second largest provider of solar power systems in the United States. In 2014, Musk promoted the idea of SolarCity building an advanced production facility in Buffalo, New York, triple the size of the largest solar plant in the United States. Construction of the factory started in 2014 and was completed in 2017. It operated as a joint venture with Panasonic until early 2020. Tesla acquired SolarCity for $2 billion in 2016 (equivalent to $2,700,000,000 in 2025) and merged it with its battery unit to create Tesla Energy. The deal's announcement resulted in a more than 10% drop in Tesla's stock price; at the time, SolarCity was facing liquidity issues. Multiple shareholder groups filed a lawsuit against Musk and Tesla's directors, stating that the purchase of SolarCity was done solely to benefit Musk and came at the expense of Tesla and its shareholders. Tesla directors settled the lawsuit in January 2020, leaving Musk the sole remaining defendant. Two years later, the court ruled in Musk's favor. In 2016, Musk co-founded Neuralink, a neurotechnology startup, with an investment of $100 million. Neuralink aims to integrate the human brain with artificial intelligence (AI) by creating devices that are embedded in the brain. Such technology could enhance memory or allow the devices to communicate with software. The company also hopes to develop devices to treat neurological conditions like spinal cord injuries. In 2022, Neuralink announced that clinical trials would begin by the end of the year. In September 2023, the Food and Drug Administration approved Neuralink to initiate six-year human trials. Neuralink has conducted animal testing on macaques at the University of California, Davis. In 2021, the company released a video in which a macaque played the video game Pong via a Neuralink implant. The company's animal trials—which have caused the deaths of some monkeys—have led to claims of animal cruelty. The Physicians Committee for Responsible Medicine has alleged that Neuralink violated the Animal Welfare Act. Employees have complained that pressure from Musk to accelerate development has led to botched experiments and unnecessary animal deaths. In 2022, a federal probe was launched into possible animal welfare violations by Neuralink.[needs update] In 2017, Musk founded the Boring Company to construct tunnels; he also revealed plans for specialized, underground, high-occupancy vehicles that could travel up to 150 miles per hour (240 km/h) and thus circumvent above-ground traffic in major cities. Early in 2017, the company began discussions with regulatory bodies and initiated construction of a 30-foot (9.1 m) wide, 50-foot (15 m) long, and 15-foot (4.6 m) deep "test trench" on the premises of SpaceX's offices, as that required no permits. The Los Angeles tunnel, less than two miles (3.2 km) in length, debuted to journalists in 2018. It used Tesla Model Xs and was reported to be a rough ride while traveling at suboptimal speeds. Two tunnel projects announced in 2018, in Chicago and West Los Angeles, have been canceled. A tunnel beneath the Las Vegas Convention Center was completed in early 2021. Local officials have approved further expansions of the tunnel system. April 14, 2022 In early 2017, Musk expressed interest in buying Twitter and had questioned the platform's commitment to freedom of speech. By 2022, Musk had reached 9.2% stake in the company, making him the largest shareholder.[d] Musk later agreed to a deal that would appoint him to Twitter's board of directors and prohibit him from acquiring more than 14.9% of the company. Days later, Musk made a $43 billion offer to buy Twitter. By the end of April Musk had successfully concluded his bid for approximately $44 billion. This included approximately $12.5 billion in loans and $21 billion in equity financing. Having backtracked on his initial decision, Musk bought the company on October 27, 2022. Immediately after the acquisition, Musk fired several top Twitter executives including CEO Parag Agrawal; Musk became the CEO instead. Under Elon Musk, Twitter instituted monthly subscriptions for a "blue check", and laid off a significant portion of the company's staff. Musk lessened content moderation and hate speech also increased on the platform after his takeover. In late 2022, Musk released internal documents relating to Twitter's moderation of Hunter Biden's laptop controversy in the lead-up to the 2020 presidential election. Musk also promised to step down as CEO after a Twitter poll, and five months later, Musk stepped down as CEO and transitioned his role to executive chairman and chief technology officer (CTO). Despite Musk stepping down as CEO, X continues to struggle with challenges such as viral misinformation, hate speech, and antisemitism controversies. Musk has been accused of trying to silence some of his critics such as Twitch streamer Asmongold, who criticized him during one of his streams. Musk has been accused of removing their accounts' blue checkmarks, which hinders visibility and is considered a form of shadow banning, or suspending their accounts without justification. Other activities In August 2013, Musk announced plans for a version of a vactrain, and assigned engineers from SpaceX and Tesla to design a transport system between Greater Los Angeles and the San Francisco Bay Area, at an estimated cost of $6 billion. Later that year, Musk unveiled the concept, dubbed the Hyperloop, intended to make travel cheaper than any other mode of transport for such long distances. In December 2015, Musk co-founded OpenAI, a not-for-profit artificial intelligence (AI) research company aiming to develop artificial general intelligence, intended to be safe and beneficial to humanity. Musk pledged $1 billion of funding to the company, and initially gave $50 million. In 2018, Musk left the OpenAI board. Since 2018, OpenAI has made significant advances in machine learning. In July 2023, Musk launched the artificial intelligence company xAI, which aims to develop a generative AI program that competes with existing offerings like OpenAI's ChatGPT. Musk obtained funding from investors in SpaceX and Tesla, and xAI hired engineers from Google and OpenAI. December 16, 2022 Musk uses a private jet owned by Falcon Landing LLC, a SpaceX-linked company, and acquired a second jet in August 2020. His heavy use of the jets and the consequent fossil fuel usage have received criticism. Musk's flight usage is tracked on social media through ElonJet. In December 2022, Musk banned the ElonJet account on Twitter, and made temporary bans on the accounts of journalists that posted stories regarding the incident, including Donie O'Sullivan, Keith Olbermann, and journalists from The New York Times, The Washington Post, CNN, and The Intercept. In October 2025, Musk's company xAI launched Grokipedia, an AI-generated online encyclopedia that he promoted as an alternative to Wikipedia. Articles on Grokipedia are generated and reviewed by xAI's Grok chatbot. Media coverage and academic analysis described Grokipedia as frequently reusing Wikipedia content but framing contested political and social topics in line with Musk's own views and right-wing narratives. A study by Cornell University researchers and NBC News stated that Grokipedia cites sources that are blacklisted or considered "generally unreliable" on Wikipedia, for example, the conspiracy site Infowars and the neo-Nazi forum Stormfront. Wired, The Guardian and Time criticized Grokipedia for factual errors and for presenting Musk himself in unusually positive terms while downplaying controversies. Politics Musk is an outlier among business leaders who typically avoid partisan political advocacy. Musk was a registered independent voter when he lived in California. Historically, he has donated to both Democrats and Republicans, many of whom serve in states in which he has a vested interest. Since 2022, his political contributions have mostly supported Republicans, with his first vote for a Republican going to Mayra Flores in the 2022 Texas's 34th congressional district special election. In 2024, he started supporting international far-right political parties, activists, and causes, and has shared misinformation and numerous conspiracy theories. Since 2024, his views have been generally described as right-wing. Musk supported Barack Obama in 2008 and 2012, Hillary Clinton in 2016, Joe Biden in 2020, and Donald Trump in 2024. In the 2020 Democratic Party presidential primaries, Musk endorsed candidate Andrew Yang and expressed support for Yang's proposed universal basic income, and endorsed Kanye West's 2020 presidential campaign. In 2021, Musk publicly expressed opposition to the Build Back Better Act, a $3.5 trillion legislative package endorsed by Joe Biden that ultimately failed to pass due to unanimous opposition from congressional Republicans and several Democrats. In 2022, gave over $50 million to Citizens for Sanity, a conservative political action committee. In 2023, he supported Republican Ron DeSantis for the 2024 U.S. presidential election, giving $10 million to his campaign, and hosted DeSantis's campaign announcement on a Twitter Spaces event. From June 2023 to January 2024, Musk hosted a bipartisan set of X Spaces with Republican and Democratic candidates, including Robert F. Kennedy Jr., Vivek Ramaswamy, and Dean Phillips. In October 2025, former vice-president Kamala Harris commented that it was a mistake from the Democratic side to not invite Musk to a White House electric vehicle event organized in August 2021 and featuring executives from General Motors, Ford and Stellantis, despite Tesla being "the major American manufacturer of extraordinary innovation in this space." Fortune remarked that this was a nod to United Auto Workers and organized labor. Harris said presidents should put aside political loyalties when it came to recognizing innovation, and guessed that the non-invitation impacted Musk's perspective. Fortune noted that, at the time, Musk said, "Yeah, seems odd that Tesla wasn't invited." A month later, he criticized Biden as "not the friendliest administration." Jacob Silverman, author of the book Gilded Rage: Elon Musk and the Radicalization of Silicon Valley, said that the tech industry represented by Musk, Thiel, Andreessen and other capitalists, actually flourished under Biden, but the tech leaders chose Trump for their common ground on cultural issues. By early 2024, Musk had become a vocal and financial supporter of Donald Trump. In July 2024, minutes after the attempted assassination of Donald Trump, Musk endorsed him for president saying; "I fully endorse President Trump and hope for his rapid recovery." During the presidential campaign, Musk joined Trump on stage at a campaign rally, and during the campaign promoted conspiracy theories and falsehoods about Democrats, election fraud and immigration, in support of Trump. Musk was the largest individual donor of the 2024 election. In 2025, Musk contributed $19 million to the Wisconsin Supreme Court race, hoping to influence the state's future redistricting efforts and its regulations governing car manufacturers and dealers. In 2023, Musk said he shunned the World Economic Forum because it was boring. The organization commented that they had not invited him since 2015. He has participated in Dialog, dubbed "Tech Bilderberg" and organized by Peter Thiel and Auren Hoffman, though. Musk's international political actions and comments have come under increasing scrutiny and criticism, especially from the governments and leaders of France, Germany, Norway, Spain and the United Kingdom, particularly due to his position in the U.S. government as well as ownership of X. An NBC News analysis found he had boosted far-right political movements to cut immigration and curtail regulation of business in at least 18 countries on six continents since 2023. During his speech after the second inauguration of Donald Trump, Musk twice made a gesture interpreted by many as a Nazi or a fascist Roman salute.[e] He thumped his right hand over his heart, fingers spread wide, and then extended his right arm out, emphatically, at an upward angle, palm down and fingers together. He then repeated the gesture to the crowd behind him. As he finished the gestures, he said to the crowd, "My heart goes out to you. It is thanks to you that the future of civilization is assured." It was widely condemned as an intentional Nazi salute in Germany, where making such gestures is illegal. The Anti-Defamation League said it was not a Nazi salute, but other Jewish organizations disagreed and condemned the salute. American public opinion was divided on partisan lines as to whether it was a fascist salute. Musk dismissed the accusations of Nazi sympathies, deriding them as "dirty tricks" and a "tired" attack. Neo-Nazi and white supremacist groups celebrated it as a Nazi salute. Multiple European political parties demanded that Musk be banned from entering their countries. The concept of DOGE emerged in a discussion between Musk and Donald Trump, and in August 2024, Trump committed to giving Musk an advisory role, with Musk accepting the offer. In November and December 2024, Musk suggested that the organization could help to cut the U.S. federal budget, consolidate the number of federal agencies, and eliminate the Consumer Financial Protection Bureau, and that its final stage would be "deleting itself". In January 2025, the organization was created by executive order, and Musk was designated a "special government employee". Musk led the organization and was a senior advisor to the president, although his official role is not clear. In sworn statement during a lawsuit, the director of the White House Office of Administration stated that Musk "is not an employee of the U.S. DOGE Service or U.S. DOGE Service Temporary Organization", "is not the U.S. DOGE Service administrator", and has "no actual or formal authority to make government decisions himself". Trump said two days later that he had put Musk in charge of DOGE. A federal judge has ruled that Musk acted as the de facto leader of DOGE. Musk's role in the second Trump administration, particularly in response to DOGE, has attracted public backlash. He was criticized for his treatment of federal government employees, including his influence over the mass layoffs of the federal workforce. He has prioritized secrecy within the organization and has accused others of violating privacy laws. A Senate report alleged that Musk could avoid up to $2 billion in legal liability as a result of DOGE's actions. In May 2025, Bill Gates accused Musk of "killing the world's poorest children" through his cuts to USAID, which modeling by Boston University estimated had resulted in 300,000 deaths by this time, most of them of children. By November 2025, the estimated death toll had increased to 400,000 children and 200,000 adults. Musk announced on May 28, 2025, that he would depart from the Trump administration as planned when the special government employee's 130 day deadline expired, with a White House official confirming that Musk's offboarding from the Trump administration was already underway. His departure was officially confirmed during a joint Oval Office press conference with Trump on May 30, 2025. @realDonaldTrump is in the Epstein files. That is the real reason they have not been made public. June 5, 2025 After leaving office, Musk criticized the Trump administration's Big Beautiful Bill, calling it a "disgusting abomination" due to its provisions increasing the deficit. A feud began between Musk and Trump, with its most notable event being Musk alleging Trump had ties to sex offender Jeffrey Epstein on X (formerly Twitter) on June 5, 2025. Trump responded on Truth Social stating that Musk went "CRAZY" after the "EV Mandate" was purportedly taken away and threatened to cut Musk's government contracts. Musk then called for a third Trump impeachment. The next day, Trump stated that he did not wish to reconcile with Musk, and added that Musk would face "very serious consequences" if he funds Democratic candidates. On June 11, Musk publicly apologized for the tweets against Trump, saying they "went too far". Views November 6, 2022 Rejecting the conservative label, Musk has described himself as a political moderate, even as his views have become more right-wing over time. His views have been characterized as libertarian and far-right, and after his involvement in European politics, they have received criticism from world leaders such as Emmanuel Macron and Olaf Scholz. Within the context of American politics, Musk supported Democratic candidates up until 2022, at which point he voted for a Republican for the first time. He has stated support for universal basic income, gun rights, freedom of speech, a tax on carbon emissions, and H-1B visas. Musk has expressed concern about issues such as artificial intelligence (AI) and climate change, and has been a critic of wealth tax, short-selling, and government subsidies. An immigrant himself, Musk has been accused of being anti-immigration, and regularly blames immigration policies for illegal immigration. He is also a pronatalist who believes population decline is the biggest threat to civilization, and identifies as a cultural Christian. Musk has long been an advocate for space colonization, especially the colonization of Mars. He has repeatedly pushed for humanity colonizing Mars, in order to become an interplanetary species and lower the risks of human extinction. Musk has promoted conspiracy theories and made controversial statements that have led to accusations of racism, sexism, antisemitism, transphobia, disseminating disinformation, and support of white pride. While describing himself as a "pro-Semite", his comments regarding George Soros and Jewish communities have been condemned by the Anti-Defamation League and the Biden White House. Musk was criticized during the COVID-19 pandemic for making unfounded epidemiological claims, defying COVID-19 lockdowns restrictions, and supporting the Canada convoy protest against vaccine mandates. He has amplified false claims of white genocide in South Africa. Musk has been critical of Israel's actions in the Gaza Strip during the Gaza war, praised China's economic and climate goals, suggested that Taiwan and China should resolve cross-strait relations, and was described as having a close relationship with the Chinese government. In Europe, Musk expressed support for Ukraine in 2022 during the Russian invasion, recommended referendums and peace deals on the annexed Russia-occupied territories, and supported the far-right Alternative for Germany political party in 2024. Regarding British politics, Musk blamed the 2024 UK riots on mass migration and open borders, criticized Prime Minister Keir Starmer for what he described as a "two-tier" policing system, and was subsequently attacked as being responsible for spreading misinformation and amplifying the far-right. He has also voiced his support for far-right activist Tommy Robinson and pledged electoral support for Reform UK. In February 2026, Musk described Spanish Prime Minister Pedro Sánchez as a "tyrant" following Sánchez's proposal to prohibit minors under the age of 16 from accessing social media platforms. Legal affairs In 2018, Musk was sued by the U.S. Securities and Exchange Commission (SEC) for a tweet stating that funding had been secured for potentially taking Tesla private.[f] The securities fraud lawsuit characterized the tweet as false, misleading, and damaging to investors, and sought to bar Musk from serving as CEO of publicly traded companies. Two days later, Musk settled with the SEC, without admitting or denying the SEC's allegations. As a result, Musk and Tesla were fined $20 million each, and Musk was forced to step down for three years as Tesla chairman but was able to remain as CEO. Shareholders filed a lawsuit over the tweet, and in February 2023, a jury found Musk and Tesla not liable. Musk has stated in interviews that he does not regret posting the tweet that triggered the SEC investigation. In 2019, Musk stated in a tweet that Tesla would build half a million cars that year. The SEC reacted by asking a court to hold him in contempt for violating the terms of the 2018 settlement agreement. A joint agreement between Musk and the SEC eventually clarified the previous agreement details, including a list of topics about which Musk needed preclearance. In 2020, a judge blocked a lawsuit that claimed a tweet by Musk regarding Tesla stock price ("too high imo") violated the agreement. Freedom of Information Act (FOIA)-released records showed that the SEC concluded Musk had subsequently violated the agreement twice by tweeting regarding "Tesla's solar roof production volumes and its stock price". In October 2023, the SEC sued Musk over his refusal to testify a third time in an investigation into whether he violated federal law by purchasing Twitter stock in 2022. In February 2024, Judge Laurel Beeler ruled that Musk must testify again. In January 2025, the SEC filed a lawsuit against Musk for securities violations related to his purchase of Twitter. In January 2024, Delaware judge Kathaleen McCormick ruled in a 2018 lawsuit that Musk's $55 billion pay package from Tesla be rescinded. McCormick called the compensation granted by the company's board "an unfathomable sum" that was unfair to shareholders. The Delaware Supreme Court overturned McCormick's decision in December 2025, restoring Musk's compensation package and awarding $1 in nominal damages. Personal life Musk became a U.S. citizen in 2002. From the early 2000s until late 2020, Musk resided in California, where both Tesla and SpaceX were founded. He then relocated to Cameron County, Texas, saying that California had become "complacent" about its economic success. While hosting Saturday Night Live in 2021, Musk stated that he has Asperger syndrome (an outdated term for autism spectrum disorder). When asked about his experience growing up with Asperger's syndrome in a TED2022 conference in Vancouver, Musk stated that "the social cues were not intuitive ... I would just tend to take things very literally ... but then that turned out to be wrong — [people were not] simply saying exactly what they mean, there's all sorts of other things that are meant, and [it] took me a while to figure that out." Musk suffers from back pain and has undergone several spine-related surgeries, including a disc replacement. In 2000, he contracted a severe case of malaria while on vacation in South Africa. Musk has stated he uses doctor-prescribed ketamine for occasional depression and that he doses "a small amount once every other week or something like that"; since January 2024, some media outlets have reported that he takes ketamine, marijuana, LSD, ecstasy, mushrooms, cocaine and other drugs. Musk at first refused to comment on his alleged drug use, before responding that he had not tested positive for drugs, and that if drugs somehow improved his productivity, "I would definitely take them!". The New York Times' investigations revealed Musk's overuse of ketamine and numerous other drugs, as well as strained family relationships and concerns from close associates who have become troubled by his public behavior as he became more involved in political activities and government work. According to The Washington Post, President Trump described Musk as "a big-time drug addict". Through his own label Emo G Records, Musk released a rap track, "RIP Harambe", on SoundCloud in March 2019. The following year, he released an EDM track, "Don't Doubt Ur Vibe", featuring his own lyrics and vocals. Musk plays video games, which he stated has a "'restoring effect' that helps his 'mental calibration'". Some games he plays include Quake, Diablo IV, Elden Ring, and Polytopia. Musk once claimed to be one of the world's top video game players but has since admitted to "account boosting", or cheating by hiring outside services to achieve top player rankings. Musk has justified the boosting by claiming that all top accounts do it so he has to as well to remain competitive. In 2024 and 2025, Musk criticized the video game Assassin's Creed Shadows and its creator Ubisoft for "woke" content. Musk posted to X that "DEI kills art" and specified the inclusion of the historical figure Yasuke in the Assassin's Creed game as offensive; he also called the game "terrible". Ubisoft responded by saying that Musk's comments were "just feeding hatred" and that they were focused on producing a game not pushing politics. Musk has fathered at least 14 children, one of whom died as an infant. The Wall Street Journal reported in 2025 that sources close to Musk suggest that the "true number of Musk's children is much higher than publicly known". He had six children with his first wife, Canadian author Justine Wilson, whom he met while attending Queen's University in Ontario, Canada; they married in 2000. In 2002, their first child Nevada Musk died of sudden infant death syndrome at the age of 10 weeks. After his death, the couple used in vitro fertilization (IVF) to continue their family; they had twins in 2004, followed by triplets in 2006. The couple divorced in 2008 and have shared custody of their children. The elder twin he had with Wilson came out as a trans woman and, in 2022, officially changed her name to Vivian Jenna Wilson, adopting her mother's surname because she no longer wished to be associated with Musk. Musk began dating English actress Talulah Riley in 2008. They married two years later at Dornoch Cathedral in Scotland. In 2012, the couple divorced, then remarried the following year. After briefly filing for divorce in 2014, Musk finalized a second divorce from Riley in 2016. Musk then dated the American actress Amber Heard for several months in 2017; he had reportedly been "pursuing" her since 2012. In 2018, Musk and Canadian musician Grimes confirmed they were dating. Grimes and Musk have three children, born in 2020, 2021, and 2022.[g] Musk and Grimes originally gave their eldest child the name "X Æ A-12", which would have violated California regulations as it contained characters that are not in the modern English alphabet; the names registered on the birth certificate are "X" as a first name, "Æ A-Xii" as a middle name, and "Musk" as a last name. They received criticism for choosing a name perceived to be impractical and difficult to pronounce; Musk has said the intended pronunciation is "X Ash A Twelve". Their second child was born via surrogacy. Despite the pregnancy, Musk confirmed reports that the couple were "semi-separated" in September 2021; in an interview with Time in December 2021, he said he was single. In October 2023, Grimes sued Musk over parental rights and custody of X Æ A-Xii. Elon Musk has taken X Æ A-Xii to multiple official events in Washington, D.C. during Trump's second term in office. Also in July 2022, The Wall Street Journal reported that Musk allegedly had an affair with Nicole Shanahan, the wife of Google co-founder Sergey Brin, in 2021, leading to their divorce the following year. Musk denied the report. Musk also had a relationship with Australian actress Natasha Bassett, who has been described as "an occasional girlfriend". In October 2024, The New York Times reported Musk bought a Texas compound for his children and their mothers, though Musk denied having done so. Musk also has four children with Shivon Zilis, director of operations and special projects at Neuralink: twins born via IVF in 2021, a child born in 2024 via surrogacy and a child born in 2025.[h] On February 14, 2025, Ashley St. Clair, an influencer and author, posted on X claiming to have given birth to Musk's son Romulus five months earlier, which media outlets reported as Musk's supposed thirteenth child.[i] On February 22, 2025, it was reported that St Clair had filed for sole custody of her five-month-old son and for Musk to be recognised as the child's father. On March 31, 2025, Musk wrote that, while he was unsure if he was the father of St. Clair's child, he had paid St. Clair $2.5 million and would continue paying her $500,000 per year.[j] Later reporting from the Wall Street Journal indicated that $1 million of these payments to St. Clair were structured as a loan. In 2014, Musk and Ghislaine Maxwell appeared together in a photograph taken at an Academy Awards after-party, which Musk later described as a "photobomb". The January 2026 Epstein files contain emails between Musk and Epstein from 2012 to 2013, after Epstein's first conviction. Emails released on January 30, 2026, indicated that Epstein invited Musk to visit his private island on multiple occasions. The correspondence showed that while Epstein repeatedly encouraged Musk to attend, Musk did not visit the island. In one instance, Musk discussed the possibility of attending a party with his then-wife Talulah Riley and asked which day would be the "wildest party"; according to the emails, the visit did not take place after Epstein later cancelled the plans.[k] On Christmas day in 2012, Musk emailed Epstein asking "Do you have any parties planned? I’ve been working to the edge of sanity this year and so, once my kids head home after Christmas, I really want to hit the party scene in St Barts or elsewhere and let loose. The invitation is much appreciated, but a peaceful island experience is the opposite of what I’m looking for". Epstein replied that the "ratio on my island" might make Musk's wife uncomfortable to which Musk responded, "Ratio is not a problem for Talulah". On September 11, 2013, Epstein sent an email asking Musk if he had any plans for coming to New York for the opening of the United Nations General Assembly where many "interesting people" would be coming to his house to which Musk responded that "Flying to NY to see UN diplomats do nothing would be an unwise use of time". Epstein responded by stating "Do you think i am retarded. Just kidding, there is no one over 25 and all very cute." Musk has denied any close relationship with Epstein and described him as a "creep" who attempted to ingratiate himself with influential people. When Musk was asked in 2019 if he introduced Epstein to Mark Zuckerberg, Musk responded: "I don’t recall introducing Epstein to anyone, as I don’t know the guy well enough to do so." The released emails nonetheless showed cordial exchanges on a range of topics, including Musk's inquiry about parties on the island. The correspondence also indicated that Musk suggested hosting Epstein at SpaceX, while Epstein separately discussed plans to tour SpaceX and bring "the girls", though there is no evidence that such a visit occurred. Musk has described the release of the files a "distraction", later accusing the second Trump administration of suppressing them to protect powerful individuals, including Trump himself.[l] Wealth Elon Musk is the wealthiest person in the world, with an estimated net worth of US$690 billion as of January 2026, according to the Bloomberg Billionaires Index, and $852 billion according to Forbes, primarily from his ownership stakes in SpaceX and Tesla. Having been first listed on the Forbes Billionaires List in 2012, around 75% of Musk's wealth was derived from Tesla stock in November 2020, although he describes himself as "cash poor". According to Forbes, he became the first person in the world to achieve a net worth of $300 billion in 2021; $400 billion in December 2024; $500 billion in October 2025; $600 billion in mid-December 2025; $700 billion later that month; and $800 billion in February 2026. In November 2025, a Tesla pay package worth potentially $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Public image Although his ventures have been highly influential within their separate industries starting in the 2000s, Musk only became a public figure in the early 2010s. He has been described as an eccentric who makes spontaneous and impactful decisions, while also often making controversial statements, contrary to other billionaires who prefer reclusiveness to protect their businesses. Musk's actions and his expressed views have made him a polarizing figure. Biographer Ashlee Vance described people's opinions of Musk as polarized due to his "part philosopher, part troll" persona on Twitter. He has drawn denouncement for using his platform to mock the self-selection of personal pronouns, while also receiving praise for bringing international attention to matters like British survivors of grooming gangs. Musk has been described as an American oligarch due to his extensive influence over public discourse, social media, industry, politics, and government policy. After Trump's re-election, Musk's influence and actions during the transition period and the second presidency of Donald Trump led some to call him "President Musk", the "actual president-elect", "shadow president" or "co-president". Awards for his contributions to the development of the Falcon rockets include the American Institute of Aeronautics and Astronautics George Low Transportation Award in 2008, the Fédération Aéronautique Internationale Gold Space Medal in 2010, and the Royal Aeronautical Society Gold Medal in 2012. In 2015, he received an honorary doctorate in engineering and technology from Yale University and an Institute of Electrical and Electronics Engineers Honorary Membership. Musk was elected a Fellow of the Royal Society (FRS) in 2018.[m] In 2022, Musk was elected to the National Academy of Engineering. Time has listed Musk as one of the most influential people in the world in 2010, 2013, 2018, and 2021. Musk was selected as Time's "Person of the Year" for 2021. Then Time editor-in-chief Edward Felsenthal wrote that, "Person of the Year is a marker of influence, and few individuals have had more influence than Musk on life on Earth, and potentially life off Earth too." Notes References Works cited Further reading External links |
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Contents Cunning folk Cunning folk, also known as folk healers or wise folk, were practitioners of folk medicine, helpful folk magic and divination in Europe from the Middle Ages until the 20th century. Their practices were known as the cunning craft. Their services also included thwarting witchcraft. Although some cunning folk were denounced as witches themselves, they made up a minority of those accused, and the common people generally made a distinction between the two. The name 'cunning folk' originally referred to folk-healers and magic-workers in Britain, but the name is now applied as an umbrella term for similar people in other parts of Europe. European names Names given to folk-healers and magic-workers in Europe include: Scandinavia In Scandinavia, the klok gumma ("wise woman") or klok gubbe ("wise man"), and collectively De kloka ("The Wise ones"), as they were known in Swedish, were usually elder members of the community who acted as folk healers and midwives as well as using folk magic such as magic rhymes. In Denmark, they were called klog mand ("wise man") and klog kone ("wise woman") and collectively as kloge folk ("wise folk"). Many Norwegian and Danish practitioners of folk magic and medicine would have a copy of the "Svartebok" (or "black book"), a tome that, according to some, was written by Cyprianus, that is, the Saint of Necromancers, Cyprian of Antioch, and to others to have been the Sixth and Seventh books of the Bible (or "Books of Moses" as the Pentateuch is known in Denmark and Norway) that were left out of the official Old Testament by the learned so that the common folk would not learn the knowledge held within the text. A formulary found in a "black book" recovered from a farm near Elverum contains many formulas such as one for a toothache that commands the user of the charm to write the words "Agerin, Nagerin, Vagerin, Jagerin, Ipagerin, Sipia" on a piece of paper using a new pen, cut the paper into three small pieces, place the first piece onto the tooth in the evening and in the morning spit the piece into the fire. This should then be repeated with the other pieces. Another charm used for helping a woman who is having a difficult labour says to take two white lily roots and give them to the mother to eat. There is an old idea that it was "Klok gumma" who often fell victim to the Witch Trials in the 17th century, but this does not appear to be true. However, some "wise women" and "wise men" were punished, not for witchcraft but often under the indictment point of "superstition" (Swedish: Vidskepelse). In the 1670s, the wise man Johan Eriksson of Knutby was sentenced to seven gauntlet for "superstition", and again in the 1680s to nine. Per Ericsson of Dalarna, who read the diseases in wine, was punished both in 1720 and 1726. Brita Biörn of Gotland said in court that she learned to heal the sick when she spent some time in the underworld, and she was sentenced to prison terms in both 1722 and 1737. The punishment of Sweden's "cunning folk" only seemed to have the opposite effect. Ericsson said that his clients had been coming in greater numbers after the rulings against him, and that he would be forced to hide if he was to obey the court and refrain from his practice, and in the Biörn case, the vicar complained that people from throughout the country came to seek her help, and relied on her as a god after her first sentence. The sentences, in reality, had the effect of good advertising, and Brita's daughter and granddaughter's daughter were also healing women. There are many examples of well-known "cunning folk" who were known far beyond their village boundaries, such as Ingeborg i Mjärhult in the 18th century and Kisamor and Gota-Lena in the 19th century. In the 16th century, Brigitta Andersdotter was often hired by Queen Margaret Leijonhufvud. In Norway some women such as Mor Sæther (1793–1851), Anna Brandfjeld (1810–1905) and Valborg Valland (1821–1903) achieved national fame, unusual for women of the time. The customs persisted well into the 20th century, until the medical doctor became more accessible to the public. In the 19th century, every neighbourhood in Norway had at least one folk-healer. Such beliefs in folk-medicine, magic, and the use of "black books" were taken by migrants to the Americas. However, many beliefs died out in Norwegian-American communities around the 1920s with many not having knowledge of the subject or of the "black book". Knowledge of these beliefs did last longer in Norway, even if they were not commonly believed in by Norwegians. Britain The term "cunning man" or "cunning woman" was mostly used in England and Wales from the early modern era onwards. They were also called "wizards", "wise men", "wise women", "conjurers" or in Welsh "dyn(es) hysbys" (knowing man or woman). In Cornwall they were sometimes called "pellars", which some etymologists suggest originated from the term "expellers", referring to the practice of expelling evil spirits. The term "white witch" was rarely used before the 20th century, as a "witch" generally referred to an evil person. In the Middle Ages, those who worked magic in Anglo-Saxon England were referred to by several names. Some of the spells and charms that had been used in Anglo-Saxon paganism continued to be used following Christianization. Historian Owen Davies noted, "although some such pre-Christian magic continued, to label it pagan is to misrepresent the people who used it and the context in which it was used." Some Christian clergy and secular authorities tried to smear the cunning folk by falsely branding them 'witches' and associating them with harmful 'witchcraft'. However, there was no widespread persecution of them, largely because most common people firmly distinguished between the two: witches were seen as being harmful, and cunning folk as helpful. In the 15th and 16th centuries, there had been no attempt to ban the cunning craft, although private lawsuits had been brought against some cunning folk by clients who felt that they had been cheated out of their money. Under the Witchcraft Act 1541, a person could be executed for using magic or conjuration to harm others, to cast a love spell, or to find treasure. This law was repealed no later than 1547, which Davies believes was due to those in power changing their opinion: they thought that either the death penalty was too harsh, or that magic was a moral issue that should be dealt with by the church rather than the state. For the following few decades, the magical practices of the cunning folk remained legal. In 1563, another law was passed against "Conjurations, Enchantments and Witchcrafts". This law was not as harsh as its predecessor, with the death penalty being reserved for those who were believed to have murdered someone by magical means. This law had little effect on the cunning folk, as "the attention and focus of the courts shifted away from the activities of cunning-folk and towards the maleficium of supposed witches". It was unusual for a cunning man or woman to be accused of witchcraft; in the county of Essex for instance, four hundred people had been put on trial for witchcraft, but only four of those were cunning folk. The Enlightenment saw a change in attitudes, especially amongst the educated elite. The 'Witchcraft Act 1735' repealed earlier laws against witchcraft. Unlike those laws, it did not accept the existence of magic or witches. Instead, anyone who claimed to use magic was to be punished as a swindler and could be imprisoned for one year. Germany The belief in cunning folk and the use of "white magic" to be used for healing and as protection against "black magic" was once widespread in Germany; however, during the early modern period such practices gradually became less accepted by the authorities, partly because the belief in "white magic" was viewed by the church authorities to be contrary to Biblical teachings and partly due to the loss of revenues for certain groups such as barber-surgeons and physicians, as was the case in Rothenburg ob der Tauber in which periodical action was taken against users of "white magic". The usual punishment was banishment rather than execution as was common for others convicted of witchcraft and the use of "black magic" In Germany practitioners of folk-magic were almost always female; however, by contrast the Hexenmeister (also a term for a warlock) or Hexenfinder who hunted witches and "neutralised" them on behalf of society was always male. Ireland In Ireland, names for the cunning folk in Irish include bean feasa ("wise woman"); banfháidh or fáidhbhean ("seeress"); or fear feasa ("wise man"). As in other countries, they provided services of magical healing, folk medicine, divination, and finding lost and stolen property. It was believed they could cure illnesses in both humans and livestock that were caused by fairies or witches. Their charms included a short rhyme or prayer referencing Jesus, Mary, or the saints. This was paired with a repetitive motion or ritual, and an object. They also performed funeral tasks like preparing a body for a wake and keening over the body. Gearoid Ó Crualaoich wrote that the bean feasa was also "an oracular authority for her community regarding the meaning and significance of experiences they fail to understand". Biddy Early (1798–1872) was a famous Irish cunning-woman. Italy The names used for cunning-folk in Italy vary from region to region, although such names include praticos (wise people), guaritori (healers), fattucchiere (fixers), donne che aiutano (women who help) and mago, maga or maghiardzha (sorcerers). At times, they were sometimes called streghe (witches), although usually only "behind their backs or by those who either are sceptical of their powers or believe they deal in black magic." Unlike in other parts of Europe, such as Britain, the cunning profession survived the 20th century and into the early 21st, allowing Italian-American sociologist Sabina Magliocco to make a brief study of them (2009). As in the rest of Europe, the primary role of the Italian cunning-folk was apparently in healing, both through the use of herbs and through spiritual healing. The former required knowledge about various plants and herbs on the behalf of the cunning-person, although the spiritual healing was believed to come from an inner power, known as la forza (power), la virtù (virtue) or il Segno (the sign). Such healing was often in the form of removing the malocchio, or evil eye, which had cursed someone. Italian cunning craft was, and continued to remain rooted in the country's Roman Catholicism, which is evident from the use of charms and prayers, which often call upon the aid of saints. Such magical practitioners also widely believed that they dealt with spirit beings, both benevolent (who would aid them) and malevolent (whom they would have to combat). The latter included the unquiet dead as well as supernatural witches who were believed to cause harm to people, whilst the former included ancestors, the helpful dead and saints, who could help defeat these malevolent entities. Magical tools were also utilised by Italian cunning-folk, and whilst these varied between both regions and practitioners, these commonly include fiber ropes or cords to bind, knives or scissors to cut away illness, and mirrors and weapons to reflect or scare away malevolent spirits. In Italy, the folk‑healing tradition known as Segnature is practised by rural segnatori and segnatrici, who employ ritual gestures - “signs” - alongside secret prayers to cure illness, remove curses such as the malocchio (evil eye), and influence natural phenomena. Drawing on oral transmission within families and community networks, Segnature exemplifies an enduring vernacular healing system rooted in pre‑Christian animism but syncretised with Catholic symbolism. In her 2024 monograph Italian Witchcraft and Shamanism: The Tradition of Segnature, Indigenous and Trans‑cultural Shamanic Traditions in Italy, Dr Angela Puca presents extensive ethnographic research demonstrating how these practices constitute a living form of indigenous Italian shamanism—systematised through gestures, verbal formulas, and initiation, and are experiencing renewed visibility through social media and contemporary spiritual frameworks. This positions Segnature as a coherent strand within Italy's cunning folk tradition, bridging folk Catholicism, ancestral healing, and modern esoteric sensibilities. Eastern Europe Zagovory—the use of verbal incantations—arose from Slavic pagan prayers and incantations, whether spoken, whispered or sung. These incantations have been traditionally accompanied by associated rituals, some of which are, or were, physically demanding and strenuous. One example calls for the zagovory practitioner to have either a full set of teeth, or a knife as a symbolic substitute for teeth that were missing. The traditions survived into the Christian era, largely through a process of syncretism and Christianization of the traditional rites, in which images of, and lore about, Jesus were added to the existing traditions. For instance, a healing would now be done in the name of Jesus, citing a story from the Bible. Societal concern about the practice of witchcraft centered on whether someone was using incantations or rites to cause harm. People in Russian and Ukrainian societies usually shunned those said to be witches, unless they felt they needed help against supernatural forces. Impotence, stomach pains, barrenness, hernias, abscesses, epileptic seizures, and convulsions were all attributed to evil (or witchcraft). In Russia, three quarters of those accused of witchcraft were men. American North and South America have had their own variants of these, which had taken on aspects of African and Native culture. While most of Latin America also uses Curandero/ Curandera, Appalachia had the Mountain Witches, possibly taking their name from an attempt to label similar practices amongst the Amish as Witchcraft to persecute German immigrants in Appalachia in the 1700s. The Amish practitioners are generally referred to as Braucherei, and the concept is known to them as Pow-wow. The Creole also have their own, Traiteurs. Among the Gullah-Geechee of the Carolinas is a folk healing tradition within the Hoodoo religion known as rootwork that is a combination of African, Native and European beliefs. Such folk healers there are known as Conjure Doctors or Root Doctors. Archaeological discoveries also show folk magic being practiced amongst the English colonists, with archaeological discoveries of magical talismans such as Witch Bottles, the tradition appearing to have continued up to, at least, the Civil War. All of the above traditional forms of folk magic practitioners continued within their respective communities into the 20th century, with many practices still alive and well. See also References |
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[SOURCE: https://en.wikipedia.org/wiki/Folk_devil] | [TOKENS: 1261] |
Contents Folk devil Folk devils are groups portrayed in folklore or the media as outsiders and deviant, and who are blamed for crimes or other sorts of social problems. The pursuit of folk devils frequently intensifies into a mass movement that is called a moral panic. When a moral panic is in full swing, the folk devils are the subject of loosely organized but pervasive campaigns of hostility through gossip and the spreading of urban legends. The mass media sometimes get in on the act or attempt to create new folk devils in an effort to promote controversy. Sometimes the campaign against the folk devil influences a nation's politics and legislation. Concept The concept of the folk devil was introduced by sociologist Stanley Cohen in 1972, in his study Folk Devils and Moral Panics, which analysed media controversies concerning Mods and Rockers in the United Kingdom of the 1960s. Cohen's research was based on the media storm over a violent clash between two youth subcultures, the mods and the rockers, on a bank holiday on a beach in England, 1964. Though the incident only resulted in some property damage without any serious physical injury to any of the individuals involved, several newspapers published sensationalist articles surrounding the event. Cohen examined articles written about the topic and noted a pattern of distorted facts and misrepresentation, as well as a distinct, simplistic depiction of the respective images of both groups involved in the disturbance. He articulated three stages in the media's reporting on folk devils: In the case of the mods and rockers, increased police presence the following year on the bank holiday led to another occurrence of violence. Cohen noted that the depiction of mods and rockers as violent, unruly troublemakers actually led in itself to a rise in deviant behaviour by the subcultures. Cases The basic pattern of agitations against folk devils can be seen in the history of witchhunts and similar manias of persecution; the histories of predominantly Catholic and Protestant European countries present examples of adherents of the rival Western Christian faith as folk devils; minorities and immigrants have often been seen as folk devils; in the long history of antisemitism, which frequently targets Jews with allegations of dark, murderous practices, such as blood libel; or the Roman persecution of Christians that blamed the military reverses suffered by the Roman Empire on the Christians' abandonment of paganism. In modern times, political and religious leaders in many nations have sought to present atheists and secularists as deviant outsiders who threaten the social and moral order. The identification of folk devils may reflect the efforts of powerful institutions to displace social anxieties. Some Christian groups alleged that there were fifty million Americans who engaged in some form of devil worship within their lifetimes. Another example of religious and ethnic discrimination associated with Cohen's folk devil theory would be Islamophobia, the discrimination of Muslims and those perceived as being Middle Eastern in origin. Post-9/11 reactions by Western countries stereotyped Muslims as violent, hateful, and of possessing fanatical extremist ideology. The group was depicted as posing a threat to social peace and safety in the Western world, and was subject to much hostility politically, from the media and from society. Certain politicians, pundits, and media outlets are reportedly attempting to trigger that fear response by portraying transgender individuals as society’s folk devils, crafting a narrative that paints them as sexual deviants and labeling them as “groomers.” Even as such accusations are debunked or explained, multiple states have introduced or implemented anti-LGBT legislation as a response to the panic. The proposed laws include bans on gender-affirming care, limits on the participation of transgender athletes in sports, requirements for transgender individuals to use public bathrooms based on their assigned sex at birth and restrictions on public drag performances. In a 2014 study,[citation needed] Cohen's theory of the moral panic was applied to the media reaction to the Columbine massacre. On April 20, 1999, Eric Harris and Dylan Klebold, two students from Columbine High School in Columbine, Colorado, went on a shooting spree which resulted in the deaths of 15 people. News reports in the weeks following the tragedy labelled the shooters as being “obsessed” with goth subculture, and suggested a link between Harris and Klebold's alleged identification with gothic subculture and their acts of violence. In their attempt to make sense of the Columbine shootings, journalists and other media commentators linked goths to terrorism, Charles and Marilyn Manson, self-mutilation, hostage-taking, gang culture, the Waco cult, the Oklahoma City bombing, Satanism, mass murder, ethnic cleansing in Kosovo, suicide, the Internet, video games, skinhead music, white extremism and Adolf Hitler. The ABC news program 20/20 aired a special entitled “The Goth Phenomenon” in which it reinforced claims that the shooters were heavily submerged in goth culture, and suggested that individuals of gothic subculture were to blame for homicidal activity in the past. The hostility and hysteria over the perceived ‘evil’ goth culture amplified in the years following the shooting. Goths were stereotyped in the media as being perpetuators or supporters of violence donned in black trench coats. Several high schools across the United States banned black trench coats and other apparel perceived as being linked to goth culture. Some police departments in the United States labelled gothic subculture as being “gang-based”, and as something that should be subjected to “increased police surveillance”. From the time of the Columbine shooting until 2003, there were reports of individuals sporting what was seen as gothic dress being interrogated, ticketed and arrested. In 2002, U.S. Representative Sam Graves caused Blue Springs, Missouri to be granted US$273,000 to combat the “new gothic threat”. The backlash against goth subculture after the Columbine shooting draws many parallels to Stanley Cohen's research on the mods and rockers, two other youth subcultures cast as folk devils by society. In both instances the groups were portrayed in one distinct, dumbed-down image, ostracized, stripped of any redeeming qualities, and blamed for wrongdoings in society. See also References |
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[SOURCE: https://en.wikipedia.org/wiki/Graphical_user_interface] | [TOKENS: 3198] |
Contents Graphical user interface A graphical user interface, or GUI[a], is a form of user interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation. In many applications, GUIs are used instead of text-based UIs, which are based on typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on a computer keyboard. The actions in a GUI are usually performed through direct manipulation of the graphical elements. Beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls. The term GUI tends not to be applied to other lower-display resolution types of interfaces, such as video games (where head-up displays (HUDs) are preferred), or not including flat screens like volumetric displays because the term is restricted to the scope of 2D display screens able to describe generic information, in the tradition of the computer science research at the Xerox Palo Alto Research Center. GUI and interaction design Designing the visual composition and temporal behavior of a GUI is an important part of software application programming in the area of human–computer interaction. Its goal is to enhance the efficiency and ease of use for the underlying logical design of a stored program, a design discipline named usability. Methods of user-centered design are used to ensure that the visual language introduced in the design is well-tailored to the tasks. The visible graphical interface features of an application are sometimes referred to as chrome or GUI. Typically, users interact with information by manipulating visual widgets that allow for interactions appropriate to the kind of data they hold. The widgets of a well-designed interface are selected to support the actions necessary to achieve the goals of users. A model–view–controller allows flexible structures in which the interface is independent of and indirectly linked to application functions, so the GUI can be customized easily. This allows users to select or design a different skin or theme at will, and eases the designer's work to change the interface as user needs evolve. Good GUI design relates to users more, and to system architecture less. Large widgets, such as windows, usually provide a frame or container for the main presentation content such as a web page, email message, or drawing. Smaller ones usually act as a user-input tool. A GUI may be designed for the requirements of a vertical market as application-specific GUIs. Examples include automated teller machines (ATM), point of sale (POS) touchscreens at restaurants, self-service checkouts used in a retail store, airline self-ticket and check-in, information kiosks in a public space, like a train station or a museum, and monitors or control screens in an embedded industrial application which employ a real-time operating system (RTOS). Cell phones and handheld game systems also employ application specific touchscreen GUIs. Newer automobiles use GUIs in their navigation systems and multimedia centers, or navigation multimedia center combinations. Examples Components A GUI uses a combination of technologies and devices to provide a platform that users can interact with, for the tasks of gathering and producing information. A series of elements conforming a visual language have evolved to represent information stored in computers. This makes it easier for people with few computer skills to work with and use computer software. The most common combination of such elements in GUIs is the windows, icons, text fields, canvases, menus, pointer (WIMP) paradigm, especially in personal computers. The WIMP style of interaction uses a virtual input device to represent the position of a pointing device's interface, most often a mouse, and presents information organized in windows and represented with icons. Available commands are compiled together in menus, and actions are performed making gestures with the pointing device. A window manager facilitates the interactions between windows, applications, and the windowing system. The windowing system handles hardware devices such as pointing devices, graphics hardware, and positioning of the pointer. In personal computers, all these elements are modeled through a desktop metaphor to produce a simulation called a desktop environment in which the display represents a desktop, on which documents and folders of documents can be placed. Window managers and other software combine to simulate the desktop environment with varying degrees of realism. Entries may appear in a list to make space for text and details, or in a grid for compactness and larger icons with little space underneath for text. Variations in between exist, such as a list with multiple columns of items and a grid of items with rows of text extending sideways from the icon. Multi-row and multi-column layouts commonly found on the web are "shelf" and "waterfall". The former is found on image search engines, where images appear with a fixed height but variable length, and is typically implemented with the CSS property and parameter display: inline-block;. A waterfall layout found on Imgur and TweetDeck with fixed width but variable height per item is usually implemented by specifying column-width:. Post-WIMP interface Smaller app mobile devices such as personal digital assistants (PDAs) and smartphones typically use the WIMP elements with different unifying metaphors, due to constraints in space and available input devices. Applications for which WIMP is not well suited may use newer interaction techniques, collectively termed post-WIMP UIs. As of 2011, some touchscreen-based operating systems such as Apple's iOS (iPhone) and Android use the class of GUIs named post-WIMP. These support styles of interaction using more than one finger in contact with a display, which allows actions such as pinching and rotating, which are unsupported by one pointer and mouse. Interaction Human interface devices, for the efficient interaction with a GUI include a computer keyboard, especially used together with keyboard shortcuts, pointing devices for the cursor (or rather pointer) control: mouse, pointing stick, touchpad, trackball, joystick, virtual keyboards, and head-up displays (translucent information devices at the eye level). There are also actions performed by programs that affect the GUI. For example, there are components like inotify or D-Bus to facilitate communication between computer programs. History Ivan Sutherland developed Sketchpad in 1963, widely held as the first graphical computer-aided design program. It used a light pen to create and manipulate objects in engineering drawings in realtime with coordinated graphics. In the late 1960s, researchers at the Stanford Research Institute, led by Douglas Engelbart, developed the On-Line System (NLS), which used text-based hyperlinks manipulated with a then-new device: the mouse. (A 1968 demonstration of NLS became known as "The Mother of All Demos".) In the 1970s, Engelbart's ideas were further refined and extended to graphics by researchers at Xerox PARC and specifically Alan Kay, who went beyond text-based hyperlinks and used a GUI as the main interface for the Smalltalk programming language, which ran on the Xerox Alto computer, released in 1973. Most modern general-purpose GUIs are derived from this system. The Xerox PARC GUI consisted of graphical elements such as windows, menus, radio buttons, and check boxes. The concept of icons was later introduced by David Canfield Smith, who had written a thesis on the subject under the guidance of Kay. The PARC GUI employs a pointing device along with a keyboard. These aspects can be emphasized by using the alternative term and acronym for windows, icons, menus, pointing device (WIMP). This effort culminated in the 1973 Xerox Alto, the first computer with a GUI, though the system never reached commercial production. The first commercially available computer with a GUI was the 1979 PERQ workstation, manufactured by Three Rivers Computer Corporation. Its design was heavily influenced by the work at Xerox PARC. In 1981, Xerox eventually commercialized the ideas from the Alto in the form of a new and enhanced system – the Xerox 8010 Information System – more commonly known as the Xerox Star. These early systems spurred many other GUI efforts, including Lisp machines by Symbolics and other manufacturers, the Apple Lisa (which presented the concept of menu bar and window controls) in 1983, the Apple Macintosh 128K in 1984, and the Atari ST with Digital Research's GEM, and Commodore Amiga in 1985. Visi On was released in 1983 for the IBM PC compatible computers, but was never popular due to its high hardware demands. Nevertheless, it was a crucial influence on the contemporary development of Microsoft Windows. Apple, Digital Research, IBM and Microsoft used many of Xerox's ideas to develop products, and IBM's Common User Access specifications formed the basis of the GUIs used in Microsoft Windows, IBM OS/2 Presentation Manager, and the Unix Motif toolkit and window manager. These ideas evolved to create the interface found in current versions of Microsoft Windows, and in various desktop environments for Unix-like operating systems, such as macOS and Linux. Thus most current GUIs have largely common idioms. The early 1980s saw growing interest in GUIs. The Apple Lisa was released in 1983, but was expensive and commercially unsuccessful. Individual applications for many platforms presented their own GUI variants. Despite the GUI's advantages, many reviewers questioned the value of the entire concept, citing hardware limits and problems in finding compatible software. In 1984, Apple introduced the Macintosh via a a television commercial during Super Bowl XVIII, with allusions to George Orwell's novel Nineteen Eighty-Four. The goal of the commercial was to make people think about computers, identifying the user-friendly interface as a personal computer which departed from prior business-oriented systems, and becoming a signature representation of Apple products. The 1985 Atari ST shipped with the GEM GUI from Digital Research, which was also published for MS-DOS. The Amiga 1000 was released the same year, though not widely available until 1986, with the Workbench graphical desktop. This interface ran as a separate task, meaning it was very responsive and, unlike other GUIs of the time, it didn't freeze up when a program was busy. Windows 95, accompanied by an extensive marketing campaign, was a major success in the marketplace at launch and shortly became the most popular desktop operating system. In 2007, with the iPhone and later in 2010 with the introduction of the iPad, Apple popularized the post-WIMP style of interaction for multi-touch screens, and those devices were considered to be milestones in the development of mobile devices. The GUIs familiar to most people as of the mid-late 2010s are Windows, macOS, and the X Window System interfaces for desktop and laptop computers, and Android, Apple's iOS, Symbian, BlackBerry OS, Windows Phone/Windows 10 Mobile, Tizen, WebOS, and Firefox OS for handheld (smartphone) devices. Comparison to other interfaces People said it's more of a right-brain machine and all that—I think there is some truth to that. I think there is something to dealing in a graphical interface and a more kinetic interface—you're really moving information around, you're seeing it move as though it had substance. And you don't see that on a PC. The PC is very much of a conceptual machine; you move information around the way you move formulas, elements on either side of an equation. I think there's a difference. — Andrew Fluegelman on the Macintosh, 1985 Since the commands available in command line interfaces can be many, complex operations can be performed using a short sequence of words and symbols. Custom functions may be used to facilitate access to frequent actions. Command-line interfaces are more lightweight, as they only recall information necessary for a task; for example, no preview thumbnails or graphical rendering of web pages. This allows greater efficiency and productivity once many commands are learned. But reaching this level takes some time because the command words may not be easily discoverable or mnemonic. Also, using the command line can become slow and error-prone when users must enter long commands comprising many parameters or several different filenames at once. However, windows, icons, menus, pointer (WIMP) interfaces present users with many widgets that represent and can trigger some of the system's available commands. GUIs can be made quite hard when dialogs are buried deep in a system or moved about to different places during redesigns. Also, icons and dialog boxes are usually harder for users to script. WIMPs extensively use modes, as the meaning of all keys and clicks on specific positions on the screen are redefined all the time. Command-line interfaces use modes only in limited forms, such as for current directory and environment variables. Most modern operating systems provide both a GUI and some level of a CLI, although the GUIs usually receive more attention. GUI wrappers find a way around the command-line interface versions (CLI) of (typically) Linux and Unix-like software applications and their text-based UIs or typed command labels. While command-line or text-based applications allow users to run a program non-interactively, GUI wrappers atop them avoid the steep learning curve of the command-line, which requires commands to be typed on the keyboard. By starting a GUI wrapper, users can intuitively interact with, start, stop, and change its working parameters, through graphical icons and visual indicators of a desktop environment, for example. Applications may also provide both interfaces, and when they do the GUI is usually a WIMP wrapper around the command-line version. This is especially common with applications designed for Unix-like operating systems. The latter used to be implemented first because it allowed the developers to focus exclusively on their product's functionality without bothering about interface details such as designing icons and placing buttons. Designing programs this way also allows users to run the program in a shell script. Three-dimensional graphical user interface Many environments and games use the methods of 3D graphics to project 3D GUI objects onto the screen. The use of 3D graphics has become increasingly common in mainstream operating systems (ex. Windows Aero, and Aqua (macOS)) to create attractive interfaces, termed eye candy (which includes, for example, the use of drop shadows underneath windows and the cursor), or for functional purposes only possible using three dimensions. For example, user switching is represented by rotating a cube with faces representing each user's workspace, and window management is represented via a Rolodex-style flipping mechanism in Windows Vista (see Windows Flip 3D). In both cases, the operating system transforms windows on-the-fly while continuing to update the content of those windows. The GUI is usually WIMP-based, although occasionally other metaphors surface, such as those used in Microsoft Bob, 3dwm, File System Navigator, File System Visualizer, 3D Mailbox, and GopherVR. Zooming (ZUI) is a related technology that promises to deliver the representation benefits of 3D environments without their usability drawbacks of orientation problems and hidden objects. In 2006, Hillcrest Labs introduced the first ZUI for television. Other innovations include the menus on the PlayStation 2; the menus on the Xbox; Sun's Project Looking Glass; Metisse, which was similar to Project Looking Glass; BumpTop, where users can manipulate documents and windows with realistic movement and physics as if they were physical documents; Croquet OS, which is built for collaboration; and compositing window managers such as Enlightenment and Compiz. Augmented reality and virtual reality also make use of 3D GUI elements. 3D GUIs have appeared in science fiction literature and films, even before certain technologies were feasible or in common use. See also Notes References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Lod#cite_ref-42] | [TOKENS: 4733] |
Contents Lod Lod (Hebrew: לוד, fully vocalized: לֹד), also known as Lydda (Ancient Greek: Λύδδα) and Lidd (Arabic: اللِّدّ, romanized: al-Lidd, or اللُّدّ, al-Ludd), is a city 15 km (9+1⁄2 mi) southeast of Tel Aviv and 40 km (25 mi) northwest of Jerusalem in the Central District of Israel. It is situated between the lower Shephelah on the east and the coastal plain on the west. The city had a population of 90,814 in 2023. Lod has been inhabited since at least the Neolithic period. It is mentioned a few times in the Hebrew Bible and in the New Testament. Between the 5th century BCE and up until the late Roman period, it was a prominent center for Jewish scholarship and trade. Around 200 CE, the city became a Roman colony and was renamed Diospolis (Ancient Greek: Διόσπολις, lit. 'city of Zeus'). Tradition identifies Lod as the 4th century martyrdom site of Saint George; the Church of Saint George and Mosque of Al-Khadr located in the city is believed to have housed his remains. Following the Arab conquest of the Levant, Lod served as the capital of Jund Filastin; however, a few decades later, the seat of power was transferred to Ramla, and Lod slipped in importance. Under Crusader rule, the city was a Catholic diocese of the Latin Church and it remains a titular see to this day.[citation needed] Lod underwent a major change in its population in the mid-20th century. Exclusively Palestinian Arab in 1947, Lod was part of the area designated for an Arab state in the United Nations Partition Plan for Palestine; however, in July 1948, the city was occupied by the Israel Defense Forces, and most of its Arab inhabitants were expelled in the Palestinian expulsion from Lydda and Ramle. The city was largely resettled by Jewish immigrants, most of them expelled from Arab countries. Today, Lod is one of Israel's mixed cities, with an Arab population of 30%. Lod is one of Israel's major transportation hubs. The main international airport, Ben Gurion Airport, is located 8 km (5 miles) north of the city. The city is also a major railway and road junction. Religious references The Hebrew name Lod appears in the Hebrew Bible as a town of Benjamin, founded along with Ono by Shamed or Shamer (1 Chronicles 8:12; Ezra 2:33; Nehemiah 7:37; 11:35). In Ezra 2:33, it is mentioned as one of the cities whose inhabitants returned after the Babylonian captivity. Lod is not mentioned among the towns allocated to the tribe of Benjamin in Joshua 18:11–28. The name Lod derives from a tri-consonantal root not extant in Northwest Semitic, but only in Arabic (“to quarrel; withhold, hinder”). An Arabic etymology of such an ancient name is unlikely (the earliest attestation is from the Achaemenid period). In the New Testament, the town appears in its Greek form, Lydda, as the site of Peter's healing of Aeneas in Acts 9:32–38. The city is also mentioned in an Islamic hadith as the location of the battlefield where the false messiah (al-Masih ad-Dajjal) will be slain before the Day of Judgment. History The first occupation dates to the Neolithic in the Near East and is associated with the Lodian culture. Occupation continued in the Levant Chalcolithic. Pottery finds have dated the initial settlement in the area now occupied by the town to 5600–5250 BCE. In the Early Bronze, it was an important settlement in the central coastal plain between the Judean Shephelah and the Mediterranean coast, along Nahal Ayalon. Other important nearby sites were Tel Dalit, Tel Bareqet, Khirbat Abu Hamid (Shoham North), Tel Afeq, Azor and Jaffa. Two architectural phases belong to the late EB I in Area B. The first phase had a mudbrick wall, while the late phase included a circulat stone structure. Later excavations have produced an occupation later, Stratum IV. It consists of two phases, Stratum IVb with mudbrick wall on stone foundations and rounded exterior corners. In Stratum IVa there was a mudbrick wall with no stone foundations, with imported Egyptian potter and local pottery imitations. Another excavations revealed nine occupation strata. Strata VI-III belonged to Early Bronze IB. The material culture showed Egyptian imports in strata V and IV. Occupation continued into Early Bronze II with four strata (V-II). There was continuity in the material culture and indications of centralized urban planning. North to the tell were scattered MB II burials. The earliest written record is in a list of Canaanite towns drawn up by the Egyptian pharaoh Thutmose III at Karnak in 1465 BCE. From the fifth century BCE until the Roman period, the city was a centre of Jewish scholarship and commerce. According to British historian Martin Gilbert, during the Hasmonean period, Jonathan Maccabee and his brother, Simon Maccabaeus, enlarged the area under Jewish control, which included conquering the city. The Jewish community in Lod during the Mishnah and Talmud era is described in a significant number of sources, including information on its institutions, demographics, and way of life. The city reached its height as a Jewish center between the First Jewish-Roman War and the Bar Kokhba revolt, and again in the days of Judah ha-Nasi and the start of the Amoraim period. The city was then the site of numerous public institutions, including schools, study houses, and synagogues. In 43 BC, Cassius, the Roman governor of Syria, sold the inhabitants of Lod into slavery, but they were set free two years later by Mark Antony. During the First Jewish–Roman War, the Roman proconsul of Syria, Cestius Gallus, razed the town on his way to Jerusalem in Tishrei 66 CE. According to Josephus, "[he] found the city deserted, for the entire population had gone up to Jerusalem for the Feast of Tabernacles. He killed fifty people whom he found, burned the town and marched on". Lydda was occupied by Emperor Vespasian in 68 CE. In the period following the destruction of Jerusalem in 70 CE, Rabbi Tarfon, who appears in many Tannaitic and Jewish legal discussions, served as a rabbinic authority in Lod. During the Kitos War, 115–117 CE, the Roman army laid siege to Lod, where the rebel Jews had gathered under the leadership of Julian and Pappos. Torah study was outlawed by the Romans and pursued mostly in the underground. The distress became so great, the patriarch Rabban Gamaliel II, who was shut up there and died soon afterwards, permitted fasting on Ḥanukkah. Other rabbis disagreed with this ruling. Lydda was next taken and many of the Jews were executed; the "slain of Lydda" are often mentioned in words of reverential praise in the Talmud. In 200 CE, emperor Septimius Severus elevated the town to the status of a city, calling it Colonia Lucia Septimia Severa Diospolis. The name Diospolis ("City of Zeus") may have been bestowed earlier, possibly by Hadrian. At that point, most of its inhabitants were Christian. The earliest known bishop is Aëtius, a friend of Arius. During the following century (200-300CE), it's said that Joshua ben Levi founded a yeshiva in Lod. In December 415, the Council of Diospolis was held here to try Pelagius; he was acquitted. In the sixth century, the city was renamed Georgiopolis after St. George, a soldier in the guard of the emperor Diocletian, who was born there between 256 and 285 CE. The Church of Saint George and Mosque of Al-Khadr is named for him. The 6th-century Madaba map shows Lydda as an unwalled city with a cluster of buildings under a black inscription reading "Lod, also Lydea, also Diospolis". An isolated large building with a semicircular colonnaded plaza in front of it might represent the St George shrine. After the Muslim conquest of Palestine by Amr ibn al-'As in 636 CE, Lod which was referred to as "al-Ludd" in Arabic served as the capital of Jund Filastin ("Military District of Palaestina") before the seat of power was moved to nearby Ramla during the reign of the Umayyad Caliph Suleiman ibn Abd al-Malik in 715–716. The population of al-Ludd was relocated to Ramla, as well. With the relocation of its inhabitants and the construction of the White Mosque in Ramla, al-Ludd lost its importance and fell into decay. The city was visited by the local Arab geographer al-Muqaddasi in 985, when it was under the Fatimid Caliphate, and was noted for its Great Mosque which served the residents of al-Ludd, Ramla, and the nearby villages. He also wrote of the city's "wonderful church (of St. George) at the gate of which Christ will slay the Antichrist." The Crusaders occupied the city in 1099 and named it St Jorge de Lidde. It was briefly conquered by Saladin, but retaken by the Crusaders in 1191. For the English Crusaders, it was a place of great significance as the birthplace of Saint George. The Crusaders made it the seat of a Latin Church diocese, and it remains a titular see. It owed the service of 10 knights and 20 sergeants, and it had its own burgess court during this era. In 1226, Ayyubid Syrian geographer Yaqut al-Hamawi visited al-Ludd and stated it was part of the Jerusalem District during Ayyubid rule. Sultan Baybars brought Lydda again under Muslim control by 1267–8. According to Qalqashandi, Lydda was an administrative centre of a wilaya during the fourteenth and fifteenth century in the Mamluk empire. Mujir al-Din described it as a pleasant village with an active Friday mosque. During this time, Lydda was a station on the postal route between Cairo and Damascus. In 1517, Lydda was incorporated into the Ottoman Empire as part of the Damascus Eyalet, and in the 1550s, the revenues of Lydda were designated for the new waqf of Hasseki Sultan Imaret in Jerusalem, established by Hasseki Hurrem Sultan (Roxelana), the wife of Suleiman the Magnificent. By 1596 Lydda was a part of the nahiya ("subdistrict") of Ramla, which was under the administration of the liwa ("district") of Gaza. It had a population of 241 households and 14 bachelors who were all Muslims, and 233 households who were Christians. They paid a fixed tax-rate of 33,3 % on agricultural products, including wheat, barley, summer crops, vineyards, fruit trees, sesame, special product ("dawalib" =spinning wheels), goats and beehives, in addition to occasional revenues and market toll, a total of 45,000 Akçe. All of the revenue went to the Waqf. In 1051 AH/1641/2, the Bedouin tribe of al-Sawālima from around Jaffa attacked the villages of Subṭāra, Bayt Dajan, al-Sāfiriya, Jindās, Lydda and Yāzūr belonging to Waqf Haseki Sultan. The village appeared as Lydda, though misplaced, on the map of Pierre Jacotin compiled in 1799. Missionary William M. Thomson visited Lydda in the mid-19th century, describing it as a "flourishing village of some 2,000 inhabitants, imbosomed in noble orchards of olive, fig, pomegranate, mulberry, sycamore, and other trees, surrounded every way by a very fertile neighbourhood. The inhabitants are evidently industrious and thriving, and the whole country between this and Ramleh is fast being filled up with their flourishing orchards. Rarely have I beheld a rural scene more delightful than this presented in early harvest ... It must be seen, heard, and enjoyed to be appreciated." In 1869, the population of Ludd was given as: 55 Catholics, 1,940 "Greeks", 5 Protestants and 4,850 Muslims. In 1870, the Church of Saint George was rebuilt. In 1892, the first railway station in the entire region was established in the city. In the second half of the 19th century, Jewish merchants migrated to the city, but left after the 1921 Jaffa riots. In 1882, the Palestine Exploration Fund's Survey of Western Palestine described Lod as "A small town, standing among enclosure of prickly pear, and having fine olive groves around it, especially to the south. The minaret of the mosque is a very conspicuous object over the whole of the plain. The inhabitants are principally Moslim, though the place is the seat of a Greek bishop resident of Jerusalem. The Crusading church has lately been restored, and is used by the Greeks. Wells are found in the gardens...." From 1918, Lydda was under the administration of the British Mandate in Palestine, as per a League of Nations decree that followed the Great War. During the Second World War, the British set up supply posts in and around Lydda and its railway station, also building an airport that was renamed Ben Gurion Airport after the death of Israel's first prime minister in 1973. At the time of the 1922 census of Palestine, Lydda had a population of 8,103 inhabitants (7,166 Muslims, 926 Christians, and 11 Jews), the Christians were 921 Orthodox, 4 Roman Catholics and 1 Melkite. This had increased by the 1931 census to 11,250 (10,002 Muslims, 1,210 Christians, 28 Jews, and 10 Bahai), in a total of 2475 residential houses. In 1938, Lydda had a population of 12,750. In 1945, Lydda had a population of 16,780 (14,910 Muslims, 1,840 Christians, 20 Jews and 10 "other"). Until 1948, Lydda was an Arab town with a population of around 20,000—18,500 Muslims and 1,500 Christians. In 1947, the United Nations proposed dividing Mandatory Palestine into two states, one Jewish state and one Arab; Lydda was to form part of the proposed Arab state. In the ensuing war, Israel captured Arab towns outside the area the UN had allotted it, including Lydda. In December 1947, thirteen Jewish passengers in a seven-car convoy to Ben Shemen Youth Village were ambushed and murdered.In a separate incident, three Jewish youths, two men and a woman were captured, then raped and murdered in a neighbouring village. Their bodies were paraded in Lydda’s principal street. The Israel Defense Forces entered Lydda on 11 July 1948. The following day, under the impression that it was under attack, the 3rd Battalion was ordered to shoot anyone "seen on the streets". According to Israel, 250 Arabs were killed. Other estimates are higher: Arab historian Aref al Aref estimated 400, and Nimr al Khatib 1,700. In 1948, the population rose to 50,000 during the Nakba, as Arab refugees fleeing other areas made their way there. A key event was the Palestinian expulsion from Lydda and Ramle, with the expulsion of 50,000-70,000 Palestinians from Lydda and Ramle by the Israel Defense Forces. All but 700 to 1,056 were expelled by order of the Israeli high command, and forced to walk 17 km (10+1⁄2 mi) to the Jordanian Arab Legion lines. Estimates of those who died from exhaustion and dehydration vary from a handful to 355. The town was subsequently sacked by the Israeli army. Some scholars, including Ilan Pappé, characterize this as ethnic cleansing. The few hundred Arabs who remained in the city were soon outnumbered by the influx of Jews who immigrated to Lod from August 1948 onward, most of them from Arab countries. As a result, Lod became a predominantly Jewish town. After the establishment of the state, the biblical name Lod was readopted. The Jewish immigrants who settled Lod came in waves, first from Morocco and Tunisia, later from Ethiopia, and then from the former Soviet Union. Since 2008, many urban development projects have been undertaken to improve the image of the city. Upscale neighbourhoods have been built, among them Ganei Ya'ar and Ahisemah, expanding the city to the east. According to a 2010 report in the Economist, a three-meter-high wall was built between Jewish and Arab neighbourhoods and construction in Jewish areas was given priority over construction in Arab neighborhoods. The newspaper says that violent crime in the Arab sector revolves mainly around family feuds over turf and honour crimes. In 2010, the Lod Community Foundation organised an event for representatives of bicultural youth movements, volunteer aid organisations, educational start-ups, businessmen, sports organizations, and conservationists working on programmes to better the city. In the 2021 Israel–Palestine crisis, a state of emergency was declared in Lod after Arab rioting led to the death of an Israeli Jew. The Mayor of Lod, Yair Revivio, urged Prime Minister of Israel Benjamin Netanyahu to deploy Israel Border Police to restore order in the city. This was the first time since 1966 that Israel had declared this kind of emergency lockdown. International media noted that both Jewish and Palestinian mobs were active in Lod, but the "crackdown came for one side" only. Demographics In the 19th century and until the Lydda Death March, Lod was an exclusively Muslim-Christian town, with an estimated 6,850 inhabitants, of whom approximately 2,000 (29%) were Christian. According to the Israel Central Bureau of Statistics (CBS), the population of Lod in 2010 was 69,500 people. According to the 2019 census, the population of Lod was 77,223, of which 53,581 people, comprising 69.4% of the city's population, were classified as "Jews and Others", and 23,642 people, comprising 30.6% as "Arab". Education According to CBS, 38 schools and 13,188 pupils are in the city. They are spread out as 26 elementary schools and 8,325 elementary school pupils, and 13 high schools and 4,863 high school pupils. About 52.5% of 12th-grade pupils were entitled to a matriculation certificate in 2001.[citation needed] Economy The airport and related industries are a major source of employment for the residents of Lod. Other important factories in the city are the communication equipment company "Talard", "Cafe-Co" - a subsidiary of the Strauss Group and "Kashev" - the computer center of Bank Leumi. A Jewish Agency Absorption Centre is also located in Lod. According to CBS figures for 2000, 23,032 people were salaried workers and 1,405 were self-employed. The mean monthly wage for a salaried worker was NIS 4,754, a real change of 2.9% over the course of 2000. Salaried men had a mean monthly wage of NIS 5,821 (a real change of 1.4%) versus NIS 3,547 for women (a real change of 4.6%). The mean income for the self-employed was NIS 4,991. About 1,275 people were receiving unemployment benefits and 7,145 were receiving an income supplement. Art and culture In 2009-2010, Dor Guez held an exhibit, Georgeopolis, at the Petach Tikva art museum that focuses on Lod. Archaeology A well-preserved mosaic floor dating to the Roman period was excavated in 1996 as part of a salvage dig conducted on behalf of the Israel Antiquities Authority and the Municipality of Lod, prior to widening HeHalutz Street. According to Jacob Fisch, executive director of the Friends of the Israel Antiquities Authority, a worker at the construction site noticed the tail of a tiger and halted work. The mosaic was initially covered over with soil at the conclusion of the excavation for lack of funds to conserve and develop the site. The mosaic is now part of the Lod Mosaic Archaeological Center. The floor, with its colorful display of birds, fish, exotic animals and merchant ships, is believed to have been commissioned by a wealthy resident of the city for his private home. The Lod Community Archaeology Program, which operates in ten Lod schools, five Jewish and five Israeli Arab, combines archaeological studies with participation in digs in Lod. Sports The city's major football club, Hapoel Bnei Lod, plays in Liga Leumit (the second division). Its home is at the Lod Municipal Stadium. The club was formed by a merger of Bnei Lod and Rakevet Lod in the 1980s. Two other clubs in the city play in the regional leagues: Hapoel MS Ortodoxim Lod in Liga Bet and Maccabi Lod in Liga Gimel. Hapoel Lod played in the top division during the 1960s and 1980s, and won the State Cup in 1984. The club folded in 2002. A new club, Hapoel Maxim Lod (named after former mayor Maxim Levy) was established soon after, but folded in 2007. Notable people Twin towns-sister cities Lod is twinned with: See also References Bibliography External links |
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[SOURCE: https://en.wikipedia.org/wiki/Lod#cite_ref-43] | [TOKENS: 4733] |
Contents Lod Lod (Hebrew: לוד, fully vocalized: לֹד), also known as Lydda (Ancient Greek: Λύδδα) and Lidd (Arabic: اللِّدّ, romanized: al-Lidd, or اللُّدّ, al-Ludd), is a city 15 km (9+1⁄2 mi) southeast of Tel Aviv and 40 km (25 mi) northwest of Jerusalem in the Central District of Israel. It is situated between the lower Shephelah on the east and the coastal plain on the west. The city had a population of 90,814 in 2023. Lod has been inhabited since at least the Neolithic period. It is mentioned a few times in the Hebrew Bible and in the New Testament. Between the 5th century BCE and up until the late Roman period, it was a prominent center for Jewish scholarship and trade. Around 200 CE, the city became a Roman colony and was renamed Diospolis (Ancient Greek: Διόσπολις, lit. 'city of Zeus'). Tradition identifies Lod as the 4th century martyrdom site of Saint George; the Church of Saint George and Mosque of Al-Khadr located in the city is believed to have housed his remains. Following the Arab conquest of the Levant, Lod served as the capital of Jund Filastin; however, a few decades later, the seat of power was transferred to Ramla, and Lod slipped in importance. Under Crusader rule, the city was a Catholic diocese of the Latin Church and it remains a titular see to this day.[citation needed] Lod underwent a major change in its population in the mid-20th century. Exclusively Palestinian Arab in 1947, Lod was part of the area designated for an Arab state in the United Nations Partition Plan for Palestine; however, in July 1948, the city was occupied by the Israel Defense Forces, and most of its Arab inhabitants were expelled in the Palestinian expulsion from Lydda and Ramle. The city was largely resettled by Jewish immigrants, most of them expelled from Arab countries. Today, Lod is one of Israel's mixed cities, with an Arab population of 30%. Lod is one of Israel's major transportation hubs. The main international airport, Ben Gurion Airport, is located 8 km (5 miles) north of the city. The city is also a major railway and road junction. Religious references The Hebrew name Lod appears in the Hebrew Bible as a town of Benjamin, founded along with Ono by Shamed or Shamer (1 Chronicles 8:12; Ezra 2:33; Nehemiah 7:37; 11:35). In Ezra 2:33, it is mentioned as one of the cities whose inhabitants returned after the Babylonian captivity. Lod is not mentioned among the towns allocated to the tribe of Benjamin in Joshua 18:11–28. The name Lod derives from a tri-consonantal root not extant in Northwest Semitic, but only in Arabic (“to quarrel; withhold, hinder”). An Arabic etymology of such an ancient name is unlikely (the earliest attestation is from the Achaemenid period). In the New Testament, the town appears in its Greek form, Lydda, as the site of Peter's healing of Aeneas in Acts 9:32–38. The city is also mentioned in an Islamic hadith as the location of the battlefield where the false messiah (al-Masih ad-Dajjal) will be slain before the Day of Judgment. History The first occupation dates to the Neolithic in the Near East and is associated with the Lodian culture. Occupation continued in the Levant Chalcolithic. Pottery finds have dated the initial settlement in the area now occupied by the town to 5600–5250 BCE. In the Early Bronze, it was an important settlement in the central coastal plain between the Judean Shephelah and the Mediterranean coast, along Nahal Ayalon. Other important nearby sites were Tel Dalit, Tel Bareqet, Khirbat Abu Hamid (Shoham North), Tel Afeq, Azor and Jaffa. Two architectural phases belong to the late EB I in Area B. The first phase had a mudbrick wall, while the late phase included a circulat stone structure. Later excavations have produced an occupation later, Stratum IV. It consists of two phases, Stratum IVb with mudbrick wall on stone foundations and rounded exterior corners. In Stratum IVa there was a mudbrick wall with no stone foundations, with imported Egyptian potter and local pottery imitations. Another excavations revealed nine occupation strata. Strata VI-III belonged to Early Bronze IB. The material culture showed Egyptian imports in strata V and IV. Occupation continued into Early Bronze II with four strata (V-II). There was continuity in the material culture and indications of centralized urban planning. North to the tell were scattered MB II burials. The earliest written record is in a list of Canaanite towns drawn up by the Egyptian pharaoh Thutmose III at Karnak in 1465 BCE. From the fifth century BCE until the Roman period, the city was a centre of Jewish scholarship and commerce. According to British historian Martin Gilbert, during the Hasmonean period, Jonathan Maccabee and his brother, Simon Maccabaeus, enlarged the area under Jewish control, which included conquering the city. The Jewish community in Lod during the Mishnah and Talmud era is described in a significant number of sources, including information on its institutions, demographics, and way of life. The city reached its height as a Jewish center between the First Jewish-Roman War and the Bar Kokhba revolt, and again in the days of Judah ha-Nasi and the start of the Amoraim period. The city was then the site of numerous public institutions, including schools, study houses, and synagogues. In 43 BC, Cassius, the Roman governor of Syria, sold the inhabitants of Lod into slavery, but they were set free two years later by Mark Antony. During the First Jewish–Roman War, the Roman proconsul of Syria, Cestius Gallus, razed the town on his way to Jerusalem in Tishrei 66 CE. According to Josephus, "[he] found the city deserted, for the entire population had gone up to Jerusalem for the Feast of Tabernacles. He killed fifty people whom he found, burned the town and marched on". Lydda was occupied by Emperor Vespasian in 68 CE. In the period following the destruction of Jerusalem in 70 CE, Rabbi Tarfon, who appears in many Tannaitic and Jewish legal discussions, served as a rabbinic authority in Lod. During the Kitos War, 115–117 CE, the Roman army laid siege to Lod, where the rebel Jews had gathered under the leadership of Julian and Pappos. Torah study was outlawed by the Romans and pursued mostly in the underground. The distress became so great, the patriarch Rabban Gamaliel II, who was shut up there and died soon afterwards, permitted fasting on Ḥanukkah. Other rabbis disagreed with this ruling. Lydda was next taken and many of the Jews were executed; the "slain of Lydda" are often mentioned in words of reverential praise in the Talmud. In 200 CE, emperor Septimius Severus elevated the town to the status of a city, calling it Colonia Lucia Septimia Severa Diospolis. The name Diospolis ("City of Zeus") may have been bestowed earlier, possibly by Hadrian. At that point, most of its inhabitants were Christian. The earliest known bishop is Aëtius, a friend of Arius. During the following century (200-300CE), it's said that Joshua ben Levi founded a yeshiva in Lod. In December 415, the Council of Diospolis was held here to try Pelagius; he was acquitted. In the sixth century, the city was renamed Georgiopolis after St. George, a soldier in the guard of the emperor Diocletian, who was born there between 256 and 285 CE. The Church of Saint George and Mosque of Al-Khadr is named for him. The 6th-century Madaba map shows Lydda as an unwalled city with a cluster of buildings under a black inscription reading "Lod, also Lydea, also Diospolis". An isolated large building with a semicircular colonnaded plaza in front of it might represent the St George shrine. After the Muslim conquest of Palestine by Amr ibn al-'As in 636 CE, Lod which was referred to as "al-Ludd" in Arabic served as the capital of Jund Filastin ("Military District of Palaestina") before the seat of power was moved to nearby Ramla during the reign of the Umayyad Caliph Suleiman ibn Abd al-Malik in 715–716. The population of al-Ludd was relocated to Ramla, as well. With the relocation of its inhabitants and the construction of the White Mosque in Ramla, al-Ludd lost its importance and fell into decay. The city was visited by the local Arab geographer al-Muqaddasi in 985, when it was under the Fatimid Caliphate, and was noted for its Great Mosque which served the residents of al-Ludd, Ramla, and the nearby villages. He also wrote of the city's "wonderful church (of St. George) at the gate of which Christ will slay the Antichrist." The Crusaders occupied the city in 1099 and named it St Jorge de Lidde. It was briefly conquered by Saladin, but retaken by the Crusaders in 1191. For the English Crusaders, it was a place of great significance as the birthplace of Saint George. The Crusaders made it the seat of a Latin Church diocese, and it remains a titular see. It owed the service of 10 knights and 20 sergeants, and it had its own burgess court during this era. In 1226, Ayyubid Syrian geographer Yaqut al-Hamawi visited al-Ludd and stated it was part of the Jerusalem District during Ayyubid rule. Sultan Baybars brought Lydda again under Muslim control by 1267–8. According to Qalqashandi, Lydda was an administrative centre of a wilaya during the fourteenth and fifteenth century in the Mamluk empire. Mujir al-Din described it as a pleasant village with an active Friday mosque. During this time, Lydda was a station on the postal route between Cairo and Damascus. In 1517, Lydda was incorporated into the Ottoman Empire as part of the Damascus Eyalet, and in the 1550s, the revenues of Lydda were designated for the new waqf of Hasseki Sultan Imaret in Jerusalem, established by Hasseki Hurrem Sultan (Roxelana), the wife of Suleiman the Magnificent. By 1596 Lydda was a part of the nahiya ("subdistrict") of Ramla, which was under the administration of the liwa ("district") of Gaza. It had a population of 241 households and 14 bachelors who were all Muslims, and 233 households who were Christians. They paid a fixed tax-rate of 33,3 % on agricultural products, including wheat, barley, summer crops, vineyards, fruit trees, sesame, special product ("dawalib" =spinning wheels), goats and beehives, in addition to occasional revenues and market toll, a total of 45,000 Akçe. All of the revenue went to the Waqf. In 1051 AH/1641/2, the Bedouin tribe of al-Sawālima from around Jaffa attacked the villages of Subṭāra, Bayt Dajan, al-Sāfiriya, Jindās, Lydda and Yāzūr belonging to Waqf Haseki Sultan. The village appeared as Lydda, though misplaced, on the map of Pierre Jacotin compiled in 1799. Missionary William M. Thomson visited Lydda in the mid-19th century, describing it as a "flourishing village of some 2,000 inhabitants, imbosomed in noble orchards of olive, fig, pomegranate, mulberry, sycamore, and other trees, surrounded every way by a very fertile neighbourhood. The inhabitants are evidently industrious and thriving, and the whole country between this and Ramleh is fast being filled up with their flourishing orchards. Rarely have I beheld a rural scene more delightful than this presented in early harvest ... It must be seen, heard, and enjoyed to be appreciated." In 1869, the population of Ludd was given as: 55 Catholics, 1,940 "Greeks", 5 Protestants and 4,850 Muslims. In 1870, the Church of Saint George was rebuilt. In 1892, the first railway station in the entire region was established in the city. In the second half of the 19th century, Jewish merchants migrated to the city, but left after the 1921 Jaffa riots. In 1882, the Palestine Exploration Fund's Survey of Western Palestine described Lod as "A small town, standing among enclosure of prickly pear, and having fine olive groves around it, especially to the south. The minaret of the mosque is a very conspicuous object over the whole of the plain. The inhabitants are principally Moslim, though the place is the seat of a Greek bishop resident of Jerusalem. The Crusading church has lately been restored, and is used by the Greeks. Wells are found in the gardens...." From 1918, Lydda was under the administration of the British Mandate in Palestine, as per a League of Nations decree that followed the Great War. During the Second World War, the British set up supply posts in and around Lydda and its railway station, also building an airport that was renamed Ben Gurion Airport after the death of Israel's first prime minister in 1973. At the time of the 1922 census of Palestine, Lydda had a population of 8,103 inhabitants (7,166 Muslims, 926 Christians, and 11 Jews), the Christians were 921 Orthodox, 4 Roman Catholics and 1 Melkite. This had increased by the 1931 census to 11,250 (10,002 Muslims, 1,210 Christians, 28 Jews, and 10 Bahai), in a total of 2475 residential houses. In 1938, Lydda had a population of 12,750. In 1945, Lydda had a population of 16,780 (14,910 Muslims, 1,840 Christians, 20 Jews and 10 "other"). Until 1948, Lydda was an Arab town with a population of around 20,000—18,500 Muslims and 1,500 Christians. In 1947, the United Nations proposed dividing Mandatory Palestine into two states, one Jewish state and one Arab; Lydda was to form part of the proposed Arab state. In the ensuing war, Israel captured Arab towns outside the area the UN had allotted it, including Lydda. In December 1947, thirteen Jewish passengers in a seven-car convoy to Ben Shemen Youth Village were ambushed and murdered.In a separate incident, three Jewish youths, two men and a woman were captured, then raped and murdered in a neighbouring village. Their bodies were paraded in Lydda’s principal street. The Israel Defense Forces entered Lydda on 11 July 1948. The following day, under the impression that it was under attack, the 3rd Battalion was ordered to shoot anyone "seen on the streets". According to Israel, 250 Arabs were killed. Other estimates are higher: Arab historian Aref al Aref estimated 400, and Nimr al Khatib 1,700. In 1948, the population rose to 50,000 during the Nakba, as Arab refugees fleeing other areas made their way there. A key event was the Palestinian expulsion from Lydda and Ramle, with the expulsion of 50,000-70,000 Palestinians from Lydda and Ramle by the Israel Defense Forces. All but 700 to 1,056 were expelled by order of the Israeli high command, and forced to walk 17 km (10+1⁄2 mi) to the Jordanian Arab Legion lines. Estimates of those who died from exhaustion and dehydration vary from a handful to 355. The town was subsequently sacked by the Israeli army. Some scholars, including Ilan Pappé, characterize this as ethnic cleansing. The few hundred Arabs who remained in the city were soon outnumbered by the influx of Jews who immigrated to Lod from August 1948 onward, most of them from Arab countries. As a result, Lod became a predominantly Jewish town. After the establishment of the state, the biblical name Lod was readopted. The Jewish immigrants who settled Lod came in waves, first from Morocco and Tunisia, later from Ethiopia, and then from the former Soviet Union. Since 2008, many urban development projects have been undertaken to improve the image of the city. Upscale neighbourhoods have been built, among them Ganei Ya'ar and Ahisemah, expanding the city to the east. According to a 2010 report in the Economist, a three-meter-high wall was built between Jewish and Arab neighbourhoods and construction in Jewish areas was given priority over construction in Arab neighborhoods. The newspaper says that violent crime in the Arab sector revolves mainly around family feuds over turf and honour crimes. In 2010, the Lod Community Foundation organised an event for representatives of bicultural youth movements, volunteer aid organisations, educational start-ups, businessmen, sports organizations, and conservationists working on programmes to better the city. In the 2021 Israel–Palestine crisis, a state of emergency was declared in Lod after Arab rioting led to the death of an Israeli Jew. The Mayor of Lod, Yair Revivio, urged Prime Minister of Israel Benjamin Netanyahu to deploy Israel Border Police to restore order in the city. This was the first time since 1966 that Israel had declared this kind of emergency lockdown. International media noted that both Jewish and Palestinian mobs were active in Lod, but the "crackdown came for one side" only. Demographics In the 19th century and until the Lydda Death March, Lod was an exclusively Muslim-Christian town, with an estimated 6,850 inhabitants, of whom approximately 2,000 (29%) were Christian. According to the Israel Central Bureau of Statistics (CBS), the population of Lod in 2010 was 69,500 people. According to the 2019 census, the population of Lod was 77,223, of which 53,581 people, comprising 69.4% of the city's population, were classified as "Jews and Others", and 23,642 people, comprising 30.6% as "Arab". Education According to CBS, 38 schools and 13,188 pupils are in the city. They are spread out as 26 elementary schools and 8,325 elementary school pupils, and 13 high schools and 4,863 high school pupils. About 52.5% of 12th-grade pupils were entitled to a matriculation certificate in 2001.[citation needed] Economy The airport and related industries are a major source of employment for the residents of Lod. Other important factories in the city are the communication equipment company "Talard", "Cafe-Co" - a subsidiary of the Strauss Group and "Kashev" - the computer center of Bank Leumi. A Jewish Agency Absorption Centre is also located in Lod. According to CBS figures for 2000, 23,032 people were salaried workers and 1,405 were self-employed. The mean monthly wage for a salaried worker was NIS 4,754, a real change of 2.9% over the course of 2000. Salaried men had a mean monthly wage of NIS 5,821 (a real change of 1.4%) versus NIS 3,547 for women (a real change of 4.6%). The mean income for the self-employed was NIS 4,991. About 1,275 people were receiving unemployment benefits and 7,145 were receiving an income supplement. Art and culture In 2009-2010, Dor Guez held an exhibit, Georgeopolis, at the Petach Tikva art museum that focuses on Lod. Archaeology A well-preserved mosaic floor dating to the Roman period was excavated in 1996 as part of a salvage dig conducted on behalf of the Israel Antiquities Authority and the Municipality of Lod, prior to widening HeHalutz Street. According to Jacob Fisch, executive director of the Friends of the Israel Antiquities Authority, a worker at the construction site noticed the tail of a tiger and halted work. The mosaic was initially covered over with soil at the conclusion of the excavation for lack of funds to conserve and develop the site. The mosaic is now part of the Lod Mosaic Archaeological Center. The floor, with its colorful display of birds, fish, exotic animals and merchant ships, is believed to have been commissioned by a wealthy resident of the city for his private home. The Lod Community Archaeology Program, which operates in ten Lod schools, five Jewish and five Israeli Arab, combines archaeological studies with participation in digs in Lod. Sports The city's major football club, Hapoel Bnei Lod, plays in Liga Leumit (the second division). Its home is at the Lod Municipal Stadium. The club was formed by a merger of Bnei Lod and Rakevet Lod in the 1980s. Two other clubs in the city play in the regional leagues: Hapoel MS Ortodoxim Lod in Liga Bet and Maccabi Lod in Liga Gimel. Hapoel Lod played in the top division during the 1960s and 1980s, and won the State Cup in 1984. The club folded in 2002. A new club, Hapoel Maxim Lod (named after former mayor Maxim Levy) was established soon after, but folded in 2007. Notable people Twin towns-sister cities Lod is twinned with: See also References Bibliography External links |
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[SOURCE: https://en.wikipedia.org/wiki/Ediacaran_biota] | [TOKENS: 5226] |
Contents Ediacaran biota The Ediacaran (/ˌiːdiˈækərən/ EE-dee-ACK-ər-ən; formerly Vendian) biota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (c. 635–538.8 Mya). These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined. The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, 575 million years ago. This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominated the Ediacaran fossil record, although relationships are still a matter of debate. The organisms of the Ediacaran Period first appeared around 600 million years ago and flourished until the cusp of the Cambrian 538.8 million years ago, when the characteristic communities of fossils vanished. A diverse Ediacaran community was discovered in 1995 in Sonora, Mexico, and is approximately 555 million years in age, roughly coeval with Ediacaran fossils of the Ediacara Hills in South Australia and the White Sea on the coast of Russia. While rare fossils that may represent survivors have been found as late as the Middle Cambrian (510–500 Mya), the earlier fossil communities disappear from the record at the end of the Ediacaran, leaving only curious fragments of once-thriving ecosystems. Multiple hypotheses exist to explain the disappearance of this biota, including preservation bias, a changing environment, the advent of predators and competition from other life-forms. A sampling, reported in 2018, of late Ediacaran strata across the scattered remnants of Baltica (< 560 Mya) suggests the flourishing of the organisms coincided with conditions of low overall productivity with a very high percentage produced by bacteria, which may have led to high concentrations of dissolved organic material in the oceans. Determining where Ediacaran organisms fit in the tree of life has proven challenging; it is not even established that most of them were animals, with suggestions that they were lichens (fungus-alga symbionts), algae, protists known as foraminifera, fungi or microbial colonies, or hypothetical intermediates between plants and animals. The morphology and habit of some taxa (e.g. Funisia dorothea) suggest relationships to Porifera or Cnidaria (e.g. Auroralumina). Kimberella may show a similarity to molluscs, and other organisms have been thought to possess bilateral symmetry, although this is controversial. Most macroscopic fossils are morphologically distinct from later life-forms: they resemble discs, tubes, mud-filled bags or quilted mattresses. Due to the difficulty of deducing evolutionary relationships among these organisms, some palaeontologists have suggested that these represent completely extinct lineages that do not resemble any living organism. Palaeontologist Adolf Seilacher proposed a separate subkingdom level category Vendozoa (now renamed Vendobionta) in the Linnaean hierarchy for the Ediacaran biota. If these enigmatic organisms left no descendants, their strange forms might be seen as a "failed experiment" in multicellular life, with later multicellular life evolving independently from unrelated single-celled organisms. A 2018 study confirmed that one of the period's most-prominent and iconic fossils, Dickinsonia, included cholesterol, suggesting affinities to animals, fungi, or red algae. History The first Ediacaran fossils discovered were the disc-shaped Aspidella terranovica in 1868. Their discoverer, Scottish geologist Alexander Murray, found them useful aids for correlating the age of rocks around Newfoundland. However, since they lay below the "Primordial Strata" of the Cambrian that was then thought to contain the very first signs of animal life, a proposal four years after their discovery by Elkanah Billings that these simple forms represented fauna was dismissed by his peers. Instead, they were interpreted as gas escape structures or inorganic concretions. No similar structures elsewhere in the world were then known and the one-sided debate soon fell into obscurity. In 1933, Georg Gürich discovered specimens in Namibia but assigned them to the Cambrian Period. In 1946, Reg Sprigg noticed "jellyfishes" in the Ediacara Hills of Australia's Flinders Ranges, which were at the time believed to be Early Cambrian. It was not until the British discovery of the iconic Charnia that the Precambrian was seriously considered as containing life. This frond-shaped fossil was found in England's Charnwood Forest first by a 15 year-old girl in 1956 (Tina Negus, who was not believed[a]) and then the next year by a group of three schoolboys including 15 year-old Roger Mason. Due to the detailed geological mapping of the British Geological Survey, there was no doubt these fossils sat in Precambrian rocks. Palaeontologist Martin Glaessner finally, in 1959, made the connection between this and the earlier finds and with a combination of improved dating of existing specimens and an injection of vigour into the search, many more instances were recognised. All specimens discovered until 1967 were in coarse-grained sandstone that prevented preservation of fine details, making interpretation difficult. S.B. Misra's discovery of fossiliferous ash-beds at the Mistaken Point assemblage in Newfoundland changed all this as the delicate detail preserved by the fine ash allowed the description of features that were previously undiscernible. It was also the first discovery of Ediacarans in deep water sediments. Poor communication, combined with the difficulty in correlating globally distinct formations, led to a plethora of different names for the biota. In 1960 the French name "Ediacarien" – after the Ediacara Hills – was added to the competing terms "Sinian" and "Vendian" for terminal-Precambrian rocks, and these names were also applied to the life-forms. "Ediacaran" and "Ediacarian" were subsequently applied to the epoch or period of geological time and its corresponding rocks. In March 2004, the International Union of Geological Sciences ended the inconsistency by formally naming the terminal period of the Neoproterozoic after the Australian locality. The term "Ediacaran biota" and similar ("Ediacara" / "Ediacaran" / "Ediacarian" / "Vendian" and "fauna" / "biota") has, at various times, been used in a geographic, stratigraphic, taphonomic, or biological sense, with the latter the most common in modern literature. Preservation Microbial mats are areas of sediment stabilised by the presence of colonies of microbes that secrete sticky fluids or otherwise bind the sediment particles. They appear to migrate upwards when covered by a thin layer of sediment but this is an illusion caused by the colony's growth; individuals do not, themselves, move. If too thick a layer of sediment is deposited before they can grow or reproduce through it, parts of the colony will die leaving behind fossils with a characteristically wrinkled ("elephant skin") and tubercular texture. Some Ediacaran strata with the texture characteristics of microbial mats contain fossils, and Ediacaran fossils are almost always found in beds that contain these microbial mats. Although microbial mats were once widespread before the Cambrian substrate revolution, the evolution of grazing organisms vastly reduced their numbers. These communities are now limited to inhospitable refugia, such as the stromatolites found in Hamelin Pool Marine Nature Reserve in Shark Bay, Western Australia, where the salt levels can be twice those of the surrounding sea. The preservation of Ediacaran fossils is of interest, since as soft-bodied organisms they would normally not fossilize. Further, unlike later soft-bodied fossil biota such as the Burgess Shale or Solnhofen Limestone, the Ediacaran biota is not found in a restricted environment subject to unusual local conditions: they are global. The processes that were operating must therefore have been systemic and worldwide. Something about the Ediacaran Period permitted these delicate creatures to be left behind; the fossils may have been preserved by virtue of rapid covering by ash or sand, trapping them against the mud or microbial mats on which they lived. Their preservation was possibly enhanced by the high concentration of silica in the oceans before silica-secreting organisms such as sponges and diatoms became prevalent. Ash beds provide more detail and can readily be dated to the nearest million years or better using radiometric dating. However, it is more common to find Ediacaran fossils under sandy beds deposited by storms or in turbidites formed by high-energy bottom-scraping ocean currents. Soft-bodied organisms today rarely fossilize during such events, but the presence of widespread microbial mats probably aided preservation by stabilising their impressions in the sediment below. The rate of cementation of the overlying substrate relative to the rate of decomposition of the organism determines whether the top or bottom surface of an organism is preserved. Most disc-shaped fossils decomposed before the overlying sediment was cemented, whereupon ash or sand slumped in to fill the void, leaving a cast of the organism's underside. Conversely, quilted fossils tended to decompose after the cementation of the overlying sediment; hence their upper surfaces are preserved. Their more resistant nature is reflected in the fact that, in rare occasions, quilted fossils are found within storm beds as the high-energy sedimentation did not destroy them as it would have the less-resistant discs. Further, in some cases, the bacterial precipitation of minerals formed a "death mask", ultimately leaving a positive, cast-like impression of the organism. Morphology The Ediacaran biota exhibited a vast range of morphological characteristics. Size ranged from millimetres to metres; complexity from "blob-like" to intricate; rigidity from sturdy and resistant to jelly-soft. Almost all forms of symmetry were present. These organisms differed from earlier, mainly microbial, fossils in having an organised, differentiated multicellular construction and centimetre-plus sizes. These disparate morphologies can be broadly grouped into form taxa: Classification and interpretation Classification of the Ediacarans is inevitably difficult, hence a variety of theories exist as to their placement on the tree of life. Martin Glaessner proposed in The Dawn of Animal Life (1984) that the Ediacaran biota were recognizable crown group members of modern phyla, but were unfamiliar because they had yet to evolve the characteristic features we use in modern classification. In 1998 Mark McMenamin claimed Ediacarans did not possess an embryonic stage, and thus could not be animals. He believed that they independently evolved a nervous system and brains, meaning that "the path toward intelligent life was embarked upon more than once on this planet". In 2018 analysis of ancient sterols was taken as evidence that one of the period's most-prominent and iconic fossils, Dickinsonia, was an early animal. Since the most primitive eumetazoans—multi-cellular animals with tissues—are cnidarians, and the first recognized Ediacaran fossil Charnia looks very much like a sea pen, the first attempt to categorise these fossils designated them as jellyfish and sea pens. However, more recent discoveries have established that many of the circular forms formerly considered "cnidarian medusa" are actually holdfasts – sand-filled vesicles occurring at the base of the stem of upright frond-like Ediacarans. A notable example is the form known as Charniodiscus, a circular impression later found to be attached to the long 'stem' of a frond-like organism that now bears the name. The link between frond-like Ediacarans and sea pens has been thrown into doubt by multiple lines of evidence; chiefly the derived nature of the most frond-like pennatulacean octocorals, their absence from the fossil record before the Cenozoic, and the apparent cohesion between segments in Ediacaran frond-like organisms. Some researchers have suggested that an analysis of "growth poles" discredits the pennatulacean nature of Ediacaran fronds. Adolf Seilacher has suggested that in the Ediacaran, animals take over from giant protists as the dominant life form. The modern xenophyophores are giant single-celled protozoans found throughout the world's oceans, largely on the abyssal plain. Genomic evidence suggests that the xenophyophores are a specialised group of Foraminifera. Seilacher has suggested that the Ediacaran organisms represented a unique and extinct grouping of related forms descended from a common ancestor (clade) and created the kingdom Vendozoa, named after the now-obsolete Vendian era. He later excluded fossils identified as metazoans and relaunched the phylum "Vendobionta", which he described as "quilted" cnidarians lacking stinging cells. This absence precludes the current cnidarian method of feeding, so Seilacher suggested that the organisms may have survived by symbiosis with photosynthetic or chemoautotrophic organisms. Mark McMenamin saw such feeding strategies as characteristic for the entire biota, and referred to the marine biota of this period as a "Garden of Ediacara". Greg Retallack has proposed that Ediacaran organisms were lichens. He argues that thin sections of Ediacaran fossils show lichen-like compartments and hypha-like wisps of ferruginized clay, and that Ediacaran fossils have been found in strata that he interprets as desert soils. The suggestion has been disputed by other scientists; some have described the evidence as ambiguous and unconvincing, for instance noting that Dickinsonia fossils have been found on rippled surfaces (suggesting a marine environment), while trace fossils like Radulichnus could not have been caused by needle ice as Retallack has proposed. Ben Waggoner notes that the suggestion would place the root of the Cnidaria back from around 900 mya to between 1500 mya and 2000 mya, contradicting much other evidence. Matthew Nelsen, examining phylogenies of ascomycete fungi and chlorophyte algae (components of lichens), calibrated for time, finds no support for the hypothesis that lichens predated the vascular plants. Several classifications have been used to accommodate the Ediacaran biota at some point, from algae, to protozoans, to fungi to bacterial or microbial colonies, to hypothetical intermediates between plants and animals. A new extant genus discovered in 2014, Dendrogramma, which at the time of discovery appeared to be a basal metazoan but of unknown taxonomic placement, had been noted to have similarities with the Ediacaran fauna. It has since been found to be a siphonophore, possibly even sections of a more complex species. Origin It took almost 4 billion years from the formation of the Earth for Ediacaran fossils to first appear, 655 million years ago. While putative fossils are reported from 3,460 million years ago, the first uncontroversial evidence for life is found 2,700 million years ago, and cells with nuclei certainly existed by 1,200 million years ago. It could be that no special explanation is required: the slow process of evolution simply required 4 billion years to accumulate the necessary adaptations. Indeed, there does seem to be a slow increase in the maximum level of complexity seen over this time, with more and more complex forms of life evolving as time progresses, with traces of earlier semi-complex life such as Nimbia, found in the 610 million year old Twitya formation, and older rocks dating to 770 million years ago in Kazakhstan. On the early Earth, reactive elements, such as iron and uranium, existed in a reduced form that would react with any free oxygen produced by photosynthesising organisms. Oxygen would not be able to build up in the atmosphere until all the iron had rusted (producing banded iron formations), and all the other reactive elements had been oxidised. Donald Canfield detected records of the first significant quantities of atmospheric oxygen just before the first Ediacaran fossils appeared – and the presence of atmospheric oxygen was soon heralded as a possible trigger for the Ediacaran radiation. Oxygen seems to have accumulated in two pulses; the rise of small, sessile (stationary) organisms seems to correlate with an early oxygenation event, with larger and mobile organisms appearing around the second pulse of oxygenation. However, the assumptions underlying the reconstruction of atmospheric composition have attracted some criticism, with widespread anoxia having little effect on life where it occurs in the Early Cambrian and the Cretaceous. Periods of intense cold have also been suggested as a barrier to the evolution of multicellular life. The earliest known embryos, from China's Doushantuo Formation, appear just a million years after the Earth emerged from a global glaciation, suggesting that ice cover and cold oceans may have prevented the emergence of multicellular life. In early 2008, a team analysed the range of basic body structures ("disparity") of Ediacaran organisms from three different fossil beds: Avalon in Canada, 575 million years ago to 565 million years ago; White Sea in Russia, 560 million years ago to 550 million years ago; and Nama in Namibia, 550 million years ago to 542 million years ago, immediately before the start of the Cambrian. They found that, while the White Sea assemblage had the most species, there was no significant difference in disparity between the three groups, and concluded that before the beginning of the Avalon timespan these organisms must have gone through their own evolutionary "explosion", which may have been similar to the famous Cambrian explosion. The paucity of Ediacaran fossils after the Cambrian could simply be due to conditions no longer favoring the fossilization of Ediacaran organisms, which may have continued to thrive unpreserved for a considerable time. However, if they were common, more than the occasional specimen might be expected in exceptionally preserved fossil assemblages (Konservat-Lagerstätten) such as the Burgess Shale and Chengjiang. Although no reports of Ediacara-type organisms in the Cambrian period are widely accepted at present, a few disputed reports have been made, as well as unpublished observations of 'vendobiont' fossils from 535 Ma Orsten-type deposits in China. It has been suggested that by the Early Cambrian, organisms higher in the food chain caused the microbial mats to largely disappear. If these grazers first appeared as the Ediacaran biota started to decline, then it may suggest that they destabilised the microbial mats in a "Cambrian substrate revolution", leading to displacement or detachment of the biota; or that the destruction of the microbial substrate destabilized the ecosystem, causing extinctions. Alternatively, skeletonized animals could have fed directly on the relatively undefended Ediacaran biota. However, if the interpretation of the Ediacaran age Kimberella as a grazer is correct then this suggests that the biota had already had limited exposure to "predation". Increased competition due to the evolution of key innovations among other groups, perhaps as a response to predation, may have driven the Ediacaran biota from their niches. However, the supposed "competitive exclusion" of brachiopods by bivalve molluscs was eventually deemed to be a coincidental result of two unrelated trends. Great changes were happening at the end of the Precambrian and the start of the Early Cambrian. The breakup of the supercontinents, rising sea levels (creating shallow, "life-friendly" seas), a nutrient crisis, fluctuations in atmospheric composition, including oxygen and carbon dioxide levels, and changes in ocean chemistry (promoting biomineralisation) could all have played a part. Assemblages Late Ediacaran macrofossils are recognized globally in at least 52 formations and a variety of depositional conditions. Each formation is commonly grouped into three main types, known as assemblages and named after typical localities. Each assemblage tends to occupy its own time period and region of morphospace, and after an initial burst of diversification (or extinction) changes little for the rest of its existence. The Avalon assemblage is defined at Mistaken Point one the Avalon Peninsula of Canada, the oldest locality with a large quantity of Ediacaran fossils. The assemblage is easily dated because it contains many fine ash-beds, which are a good source of zircons used in the uranium-lead method of radiometric dating. These fine-grained ash beds also preserve exquisite detail. Constituents of this biota appear to survive through until the extinction of all Ediacarans at the base of the Cambrian. One interpretation of the biota is as deep-sea-dwelling rangeomorphs such as Charnia, all of which share a fractal growth pattern. They were probably preserved in situ (without post-mortem transportation), although this point is not universally accepted. The assemblage, while less diverse than the White Sea or Nama assemblages, resembles Carboniferous suspension-feeding communities, which may suggest filter feeding as the assemblage is often found in water too deep for photosynthesis. The White Sea or Ediacaran assemblage is named after Russia's White Sea or Australia's Ediacara Hills and is marked by much higher diversity than the Avalon or Nama assemblages. Most fossils are preserved as imprints in microbial beds, but a few are preserved within sandy units. In Australia, they are typically found in red gypsiferous and calcareous paleosols formed on loess and flood deposits in an arid cool temperate paleoclimate. Since the early 2000s, around 40 fossil surfaces preserving organisms from the White Sea Assemblage have been excavated from the Ediacara Member of the Rawnsley Quartzite in the Ediacara Hills, which lie within the Nilpena Ediacara National Park, west of the Flinders Ranges in South Australia. The fossil bed known as 1T-F has the highest diversity of Ediacaran fossils found so far, which also show significant ecological complexity. The bed includes more than 400 fossils across 16 genera. The Nama assemblage is best represented in Namibia. It is marked by extreme biotic turnover, with rates of extinction exceeding rates of origination for the whole period. Three-dimensional preservation is most common, with organisms preserved in sandy beds containing internal bedding. Dima Grazhdankin believes that these fossils represent burrowing organisms, while Guy Narbonne maintains they were surface dwellers. These beds are sandwiched between units comprising interbedded sandstones, siltstones and shales—with microbial mats, where present, usually containing the fossils. The environment is interpreted as sand bars formed at the mouth of a delta's distributaries. Mattress-like vendobionts (Ernietta, Pteridinium, Rangea) in these sandstones form a very different assemblage from vermiform fossils (Cloudina, Namacalathus) of Ediacaran "wormworld" in marine dolomite of Namibia. Since they are globally distributed – described on all continents except Antarctica – geographical boundaries do not appear to be a factor; the same fossils are found at all palaeolatitudes (the latitude where the fossil was created, accounting for continental drift - an application of paleomagnetism) and in separate sedimentary basins. An analysis of one of the White Sea fossil beds, where the layers cycle from continental seabed to inter-tidal to estuarine and back again a few times, found that a specific set of Ediacaran organisms was associated with each environment. However, while there is some delineation in organisms adapted to different environments, the three assemblages are more distinct temporally than paleoenvironmentally. Because of this, the three assemblages are often separated by temporal boundaries rather than environmental ones (timeline at right). As the Ediacaran biota represent an early stage in multicellular life's history, it is unsurprising that not all possible modes of life are occupied. It has been estimated that of 92 potentially possible modes of life – combinations of feeding style, tiering and motility — no more than a dozen are occupied by the end of the Ediacaran. Just four are represented in the Avalon assemblage. See also Footnotes References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Transfer_function] | [TOKENS: 2432] |
Contents Transfer function In engineering, a transfer function (also known as system function or network function) of a system, sub-system, or component is a mathematical function that models the system's output for each possible input. It is widely used in electronic engineering tools like circuit simulators and control systems. In simple cases, this function can be represented as a two-dimensional graph of an independent scalar input versus the dependent scalar output (known as a transfer curve or characteristic curve). Transfer functions for components are used to design and analyze systems assembled from components, particularly using the block diagram technique, in electronics and control theory. Dimensions and units of the transfer function model the output response of the device for a range of possible inputs. The transfer function of a two-port electronic circuit, such as an amplifier, might be a two-dimensional graph of the scalar voltage at the output as a function of the scalar voltage applied to the input; the transfer function of an electromechanical actuator might be the mechanical displacement of the movable arm as a function of electric current applied to the device; the transfer function of a photodetector might be the output voltage as a function of the luminous intensity of incident light of a given wavelength. The term transfer function is also used in the frequency domain analysis of systems using transform methods, such as the Laplace transform; it is the amplitude of the output as a function of the frequency of the input signal. The transfer function of an electronic filter is the amplitude at the output as a function of the frequency of a constant amplitude sine wave applied to the input. For optical imaging devices, the optical transfer function is the Fourier transform of the point spread function (a function of spatial frequency). Linear time-invariant systems Transfer functions are commonly used in the analysis of systems such as single-input single-output filters in signal processing, communication theory, and control theory. The term is often used exclusively to refer to linear time-invariant (LTI) systems. Most real systems have non-linear input–output characteristics, but many systems operated within nominal parameters (not over-driven) have behavior close enough to linear that LTI system theory is an acceptable representation of their input–output behavior. Descriptions are given in terms of a complex variable, s = σ + j ⋅ ω {\displaystyle s=\sigma +j\cdot \omega } . In many applications it is sufficient to set σ = 0 {\displaystyle \sigma =0} (thus s = j ⋅ ω {\displaystyle s=j\cdot \omega } ), which reduces the Laplace transforms with complex arguments to Fourier transforms with the real argument ω. This is common in applications primarily interested in the LTI system's steady-state response (often the case in signal processing and communication theory), not the fleeting turn-on and turn-off transient response or stability issues. For continuous-time input signal x ( t ) {\displaystyle x(t)} and output y ( t ) {\displaystyle y(t)} , dividing the Laplace transform of the output, Y ( s ) = L { y ( t ) } {\displaystyle Y(s)={\mathcal {L}}\left\{y(t)\right\}} , by the Laplace transform of the input, X ( s ) = L { x ( t ) } {\displaystyle X(s)={\mathcal {L}}\left\{x(t)\right\}} , yields the system's transfer function H ( s ) {\displaystyle H(s)} : which can be rearranged as: Discrete-time signals may be notated as arrays indexed by an integer n {\displaystyle n} (e.g. x [ n ] {\displaystyle x[n]} for input and y [ n ] {\displaystyle y[n]} for output). Instead of using the Laplace transform (which is better for continuous-time signals), discrete-time signals are dealt with using the z-transform (notated with a corresponding capital letter, like X ( z ) {\displaystyle X(z)} and Y ( z ) {\displaystyle Y(z)} ), so a discrete-time system's transfer function can be written as: H ( z ) = Y ( z ) X ( z ) = Z { y [ n ] } Z { x [ n ] } . {\displaystyle H(z)={\frac {Y(z)}{X(z)}}={\frac {{\mathcal {Z}}\{y[n]\}}{{\mathcal {Z}}\{x[n]\}}}.} A linear differential equation with constant coefficients where u and r are suitably smooth functions of t, has L as the operator defined on the relevant function space that transforms u into r. That kind of equation can be used to constrain the output function u in terms of the forcing function r. The transfer function can be used to define an operator F [ r ] = u {\displaystyle F[r]=u} that serves as a right inverse of L, meaning that L [ F [ r ] ] = r {\displaystyle L[F[r]]=r} . Solutions of the homogeneous constant-coefficient differential equation L [ u ] = 0 {\displaystyle L[u]=0} can be found by trying u = e λ t {\displaystyle u=e^{\lambda t}} . That substitution yields the characteristic polynomial The inhomogeneous case can be easily solved if the input function r is also of the form r ( t ) = e s t {\displaystyle r(t)=e^{st}} . By substituting u = H ( s ) e s t {\displaystyle u=H(s)e^{st}} , L [ H ( s ) e s t ] = e s t {\displaystyle L[H(s)e^{st}]=e^{st}} if we define Other definitions of the transfer function are used, for example 1 / p L ( i k ) . {\displaystyle 1/p_{L}(ik).} A general sinusoidal input to a system of frequency ω 0 / ( 2 π ) {\displaystyle \omega _{0}/(2\pi )} may be written exp ( j ω 0 t ) {\displaystyle \exp(j\omega _{0}t)} . The response of a system to a sinusoidal input beginning at time t = 0 {\displaystyle t=0} will consist of the sum of the steady-state response and a transient response. The steady-state response is the output of the system in the limit of infinite time, and the transient response is the difference between the response and the steady-state response; it corresponds to the homogeneous solution of the differential equation. The transfer function for an LTI system may be written as the product: where sPi are the N roots of the characteristic polynomial and will be the poles of the transfer function. In a transfer function with a single pole H ( s ) = 1 s − s P {\displaystyle H(s)={\frac {1}{s-s_{P}}}} where s P = σ P + j ω P {\displaystyle s_{P}=\sigma _{P}+j\omega _{P}} , the Laplace transform of a general sinusoid of unit amplitude will be 1 s − j ω 0 {\displaystyle {\frac {1}{s-j\omega _{0}}}} . The Laplace transform of the output will be H ( s ) s − j ω 0 {\displaystyle {\frac {H(s)}{s-j\omega _{0}}}} , and the temporal output will be the inverse Laplace transform of that function: The second term in the numerator is the transient response, and in the limit of infinite time it will diverge to infinity if σP is positive. For a system to be stable, its transfer function must have no poles whose real parts are positive. If the transfer function is strictly stable, the real parts of all poles will be negative and the transient behavior will tend to zero in the limit of infinite time. The steady-state output will be: The frequency response (or "gain") G of the system is defined as the absolute value of the ratio of the output amplitude to the steady-state input amplitude: which is the absolute value of the transfer function H ( s ) {\displaystyle H(s)} evaluated at j ω i {\displaystyle j\omega _{i}} . This result is valid for any number of transfer-function poles. The steady state behavior of a linear system for sinusoidal excitation u ( t ) = sin ( ω t ) {\displaystyle u(t)=\sin(\omega t)} can be expressed in terms of its transfer function evaluated at s = j ω {\displaystyle s=j\omega } , i.e. with real part σ = 0 {\displaystyle \sigma =0} : To show this, use the ansatz function plug it into the above given differential equation, solve for c {\displaystyle c} , and note that c = g ( j ω ) {\displaystyle c=g(j\omega )} . From the complex identity z = | z | e j arg ( z ) {\displaystyle z=|z|e^{j\arg(z)}} , the argument follows. Signal processing If x ( t ) {\displaystyle x(t)} is the input to a general linear time-invariant system, and y ( t ) {\displaystyle y(t)} is the output, and the bilateral Laplace transform of x ( t ) {\displaystyle x(t)} and y ( t ) {\displaystyle y(t)} is The output is related to the input by the transfer function H ( s ) {\displaystyle H(s)} as and the transfer function itself is If a complex harmonic signal with a sinusoidal component with amplitude | X | {\displaystyle |X|} , angular frequency ω {\displaystyle \omega } and phase arg ( X ) {\displaystyle \arg(X)} , where arg is the argument is input to a linear time-invariant system, the corresponding component in the output is: In a linear time-invariant system, the input frequency ω {\displaystyle \omega } has not changed; only the amplitude and phase angle of the sinusoid have been changed by the system. The frequency response H ( j ω ) {\displaystyle H(j\omega )} describes this change for every frequency ω {\displaystyle \omega } in terms of gain and phase shift The phase delay (the frequency-dependent amount of delay introduced to the sinusoid by the transfer function) is The group delay (the frequency-dependent amount of delay introduced to the envelope of the sinusoid by the transfer function) is found by computing the derivative of the phase shift with respect to angular frequency ω {\displaystyle \omega } , The transfer function can also be shown using the Fourier transform, a special case of bilateral Laplace transform where s = j ω {\displaystyle s=j\omega } . Although any LTI system can be described by some transfer function, "families" of special transfer functions are commonly used: Control engineering In control engineering and control theory, the transfer function is derived with the Laplace transform. The transfer function was the primary tool used in classical control engineering. A transfer matrix can be obtained for any linear system to analyze its dynamics and other properties; each element of a transfer matrix is a transfer function relating a particular input variable to an output variable. A representation bridging state space and transfer function methods was proposed by Howard H. Rosenbrock, and is known as the Rosenbrock system matrix. Imaging In imaging, transfer functions are used to describe the relationship between the scene light, the image signal and the displayed light. Non-linear systems Transfer functions do not exist for many non-linear systems, such as relaxation oscillators; however, describing functions can sometimes be used to approximate such nonlinear time-invariant systems. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Circuit_board] | [TOKENS: 6033] |
Contents Printed circuit board A printed circuit board (PCB), also known as a printed wiring board (PWB), is a laminated sandwich structure of conductive and insulating layers, each with a pattern of traces, planes and other features (similar to wires on a flat surface) etched from one or more sheet layers of copper laminated onto or between sheet layers of a non-conductive substrate. PCBs are used to connect or "wire" components to one another in an electronic circuit. Electrical components may be fixed to conductive pads on the outer layers, generally by soldering, which both electrically connects and mechanically fastens the components to the board. Another manufacturing process adds vias, metal-lined drilled holes that enable electrical interconnections between conductive layers, to boards with more than a single side. Printed circuit boards are used in nearly all electronic products today. Alternatives to PCBs include wire wrap and point-to-point construction, both once popular but now rarely used. PCBs require additional design effort to lay out the circuit, but manufacturing and assembly can be automated. Electronic design automation software is available to do much of the work of layout. Mass-producing circuits with PCBs is cheaper and faster than with other wiring methods, as components are mounted and wired in one operation. Large numbers of PCBs can be fabricated at the same time, and the layout has to be done only once. PCBs can also be made manually in small quantities, with reduced benefits. PCBs can be single-sided (one copper layer), double-sided (two copper layers on both sides of one substrate layer), or multi-layer (stacked layers of substrate with copper plating sandwiched between each and on the outside layers). Multi-layer PCBs provide much higher component density, because circuit traces on the inner layers would otherwise take up surface space between components. The rise in popularity of multilayer PCBs with more than two, and especially with more than four, copper planes was concurrent with the adoption of surface-mount technology. However, multilayer PCBs make repair, analysis, and field modification of circuits much more difficult and usually impractical. The world market for bare PCBs exceeded US$60.2 billion in 2014, and was estimated at $80.33 billion in 2024, forecast to be $96.57 billion for 2029, growing at 4.87% per annum. History Before the development of printed circuit boards, electrical and electronic circuits were wired point-to-point on a chassis. Typically, the chassis was a sheet metal frame or pan, sometimes with a wooden bottom. Components were attached to the chassis, usually by insulators when the connecting point on the chassis was metal, and then their leads were connected directly or with jumper wires by soldering, or sometimes using crimp connectors, wire connector lugs on screw terminals, or other methods. Circuits were large, bulky, heavy, and relatively fragile (even discounting the breakable glass envelopes of the vacuum tubes that were often included in the circuits), and production was labor-intensive, so the products were expensive. Development of the methods used in modern printed circuit boards started early in the 20th century. In 1903, a German inventor, Albert Hanson, described flat foil conductors laminated to an insulating board, in multiple layers. Thomas Edison experimented with chemical methods of plating conductors onto linen paper in 1904. Arthur Berry in 1913 patented a print-and-etch method in the UK, and in the United States Max Schoop obtained a patent to flame-spray metal onto a board through a patterned mask. Charles Ducas in 1925 patented a method of electroplating circuit patterns. Predating the printed circuit invention, and similar in spirit, was John Sargrove's 1936–1947 Electronic Circuit Making Equipment (ECME) that sprayed metal onto a Bakelite plastic board. The ECME could produce three radio boards per minute. The Austrian engineer Paul Eisler invented the printed circuit as part of a radio set while working in the UK around 1936. In 1941 a multi-layer printed circuit was used in German magnetic influence naval mines. Around 1943 the United States began to use the technology on a large scale to make proximity fuzes for use in World War II. Such fuzes required an electronic circuit that could withstand being fired from a gun, and could be produced in quantity. The Centralab Division of Globe Union submitted a proposal which met the requirements: a ceramic plate would be screenprinted with metallic paint for conductors and carbon material for resistors, with ceramic disc capacitors and subminiature vacuum tubes soldered in place. The technique proved viable, and the resulting patent on the process, which was classified by the U.S. Army, was assigned to Globe Union. It was not until 1984 that the Institute of Electrical and Electronics Engineers (IEEE) awarded Harry W. Rubinstein its Cledo Brunetti Award for early key contributions to the development of printed components and conductors on a common insulating substrate. Rubinstein was honored in 1984 by his alma mater, the University of Wisconsin-Madison, for his innovations in the technology of printed electronic circuits and the fabrication of capacitors. This invention also represents a step in the development of integrated circuit technology, as not only wiring but also passive components were fabricated on the ceramic substrate. In 1948, the US released the invention for commercial use. Printed circuits did not become commonplace in consumer electronics until the mid-1950s, after the Auto-Sembly process was developed by the United States Army. At around the same time in the UK work along similar lines was carried out by Geoffrey Dummer, then at the RRDE. Motorola was an early leader in bringing the process into consumer electronics, announcing in August 1952 the adoption of "plated circuits" in home radios after six years of research and a $1M investment. Motorola soon began using its trademarked term for the process, PLAcir, in its consumer radio advertisements. Hallicrafters released its first "foto-etch" printed circuit product, a clock-radio, on November 1, 1952. Even as circuit boards became available, the point-to-point chassis construction method remained in common use in industry (such as TV and hi-fi sets) into at least the late 1960s. Printed circuit boards were introduced to reduce the size, weight, and cost of parts of the circuitry. In 1960, a small consumer radio receiver might be built with all its circuitry on one circuit board, but a TV set would probably contain one or more circuit boards. Originally, every electronic component had wire leads, and a PCB had holes drilled for each wire of each component. The component leads were then inserted through the holes and soldered to the copper PCB traces. This method of assembly is called through-hole construction. In 1949, Moe Abramson and Stanislaus F. Danko of the United States Army Signal Corps developed the Auto-Sembly process in which component leads were inserted into a copper foil interconnection pattern and dip soldered. The patent they obtained in 1956 was assigned to the U.S. Army. With the development of board lamination and etching techniques, this concept evolved into the standard printed circuit board fabrication process in use today. Soldering could be done automatically by passing the board over a ripple, or wave, of molten solder in a wave-soldering machine. However, the wires and holes are inefficient since drilling holes is expensive and consumes drill bits and the protruding wires are cut off and discarded. Since the 1980s, surface mount parts have increasingly replaced through-hole components, enabling smaller boards and lower production costs, but making repairs more challenging. In the 1990s the use of multilayer surface boards became more frequent. As a result, size was further minimized and both flexible and rigid PCBs were incorporated in different devices. In 1995 PCB manufacturers began using microvia technology to produce High-Density Interconnect (HDI) PCBs. Recent advances[when?] in 3D printing have meant that there are several new techniques in PCB creation. 3D printed electronics (PEs) can be utilized to print items layer by layer and subsequently the item can be printed with a liquid ink that contains electronic functionalities.[citation needed] HDI (High Density Interconnect) technology allows for a denser design on the PCB and thus potentially smaller PCBs with more traces and components in a given area. As a result, the paths between components can be shorter. HDIs use blind/buried vias, or a combination that includes microvias. With multi-layer HDI PCBs the interconnection of several vias stacked on top of each other (stacked vías, instead of one deep buried via) can be made stronger, thus enhancing reliability in all conditions. The most common applications for HDI technology are computer and mobile phone components as well as medical equipment and military communication equipment. A 4-layer HDI microvia PCB is equivalent in quality to an 8-layer through-hole PCB, so HDI technology can reduce costs. HDI PCBs are often made using build-up film such as ajinomoto build-up film, which is also used in the production of flip chip packages. Some PCBs have optical waveguides, similar to optical fibers built on the PCB. Composition A basic PCB consists of a flat sheet of insulating material and a layer of copper foil, laminated to the substrate. Chemical etching divides the copper into separate conducting lines called tracks or circuit traces, pads for connections, vias to pass connections between layers of copper, and features such as solid conductive areas for electromagnetic shielding or other purposes. The tracks function as wires fixed in place, and are insulated from each other by air and the board substrate material. The surface of a PCB may have a coating that protects the copper from corrosion and reduces the chances of solder shorts between traces or undesired electrical contact with stray bare wires. For its function in helping to prevent solder shorts, the coating is called solder resist or solder mask. The pattern to be etched into each copper layer of a PCB is called the "artwork". The etching is usually done using photoresist which is coated onto the PCB, then exposed to light projected in the pattern of the artwork. The resist material protects the copper from dissolution into the etching solution. The etched board is then cleaned. A PCB design can be mass-reproduced in a way similar to the way photographs can be mass-duplicated from film negatives using a photographic printer. FR-4 glass epoxy is the most common insulating substrate. Another substrate material is cotton paper impregnated with phenolic resin, often tan or brown. A PCB may be printed with a legend identifying the components, test points, or identifying text. Originally, silkscreen printing was used for this purpose, but today other, finer quality printing methods are usually used. Normally the legend does not affect the function of a PCBA. A printed circuit board can have multiple layers of copper which almost always are arranged in pairs. The number of layers and the interconnection designed between them (vias, PTHs) provide a general estimate of the board complexity. Using more layers allow for more routing options and better control of signal integrity, but are also time-consuming and costly to manufacture. Likewise, selection of the vias for the board also allow fine tuning of the board size, escaping of signals off complex ICs, routing, and long term reliability, but are tightly coupled with production complexity and cost. One of the simplest boards to produce is the two-layer board. It has copper on both sides that are referred to as external layers; multi layer boards sandwich additional internal layers of copper and insulation. After two-layer PCBs, the next step up is the four-layer. The four layer board adds significantly more routing options in the internal layers as compared to the two layer board, and often some portion of the internal layers is used as ground plane or power plane, to achieve better signal integrity, higher signaling frequencies, lower EMI, and better power supply decoupling. In multi-layer boards, the layers of material are laminated together in an alternating sandwich: copper, substrate, copper, substrate, copper, etc.; each plane of copper is etched, and any internal vias (that will not extend to both outer surfaces of the finished multilayer board) are plated-through, before the layers are laminated together. Only the outer layers need be coated; the inner copper layers are protected by the adjacent substrate layers. "Through hole" components are mounted by their wire leads passing through the board and soldered to traces on the other side. "Surface mount" components are attached by their leads to copper traces on the same side of the board. A board may use both methods for mounting components. PCBs with only through-hole mounted components are now uncommon. Surface mounting is used for transistors, diodes, IC chips, resistors, and capacitors. Through-hole mounting may be used for some large components such as electrolytic capacitors and connectors. The first PCBs used through-hole technology, mounting electronic components by inserting leads through holes on one side of the board and soldering onto copper traces on the other side. Boards may be single-sided, with an unplated component side, or more compact double-sided boards, with components soldered on both sides. Horizontal installation of through-hole parts with two axial leads (such as resistors, capacitors, and diodes) is done by bending the leads 90 degrees in the same direction, inserting the part in the board (often bending leads located on the back of the board in opposite directions to improve the part's mechanical strength), soldering the leads, and trimming off the ends. Leads may be soldered either manually or by a wave soldering machine. Surface-mount technology emerged in the 1960s, gained momentum in the early 1980s, and became widely used by the mid-1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly onto the PCB surface, instead of wire leads to pass through holes. Components became much smaller and component placement on both sides of the board became more common than with through-hole mounting, allowing much smaller PCB assemblies with much higher circuit densities. Surface mounting lends itself well to a high degree of automation, reducing labor costs and greatly increasing production rates compared with through-hole circuit boards. Components can be supplied mounted on carrier tapes. Surface mount components can be about one-quarter to one-tenth of the size and weight of through-hole components, and passive components much cheaper. However, prices of semiconductor surface mount devices (SMDs) are determined more by the chip itself than the package, with little price advantage over larger packages, and some wire-ended components, such as 1N4148 small-signal switch diodes, are actually significantly cheaper than SMD equivalents. Each trace consists of a flat, narrow part of the copper foil that remains after etching. Its resistance, determined by its width, thickness, and length, must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In a multi-layer board one entire layer may be mostly solid copper to act as a ground plane for shielding and power return. For microwave circuits and high-speed digital signals (which use similar frequencies), transmission lines can be laid out in a planar form such as stripline or microstrip with carefully controlled dimensions to assure a consistent impedance. In radio-frequency and fast switching circuits the inductance and capacitance of the printed circuit board conductors become significant circuit elements, usually undesired; conversely, they can be used as a deliberate part of the circuit design, as in distributed-element filters, antennae, and fuses, obviating the need for additional discrete components. High density interconnects (HDI) PCBs have tracks or vias with a width or diameter of under 152 micrometers. Materials Laminates are manufactured by curing layers of cloth or paper with thermoset resin under pressure and heat to form an integral final piece of uniform thickness. They can be up to 4 by 8 feet (1.2 by 2.4 m) in width and length. Varying cloth weaves (threads per inch or cm), cloth thickness, and resin percentage are used to achieve the desired final thickness and dielectric characteristics. Available standard laminate thickness are listed in ANSI/IPC-D-275. The cloth or fiber material used, resin material, and the cloth to resin ratio determine the laminate's type designation (FR-4, CEM-1, G-10, etc.) and therefore the characteristics of the laminate produced. Important characteristics are the level to which the laminate is fire retardant, the dielectric constant (er), the loss tangent (tan δ), the tensile strength, the shear strength, the glass transition temperature (Tg), and the Z-axis expansion coefficient (how much the thickness changes with temperature). There are quite a few different dielectrics that can be chosen to provide different insulating values depending on the requirements of the circuit. Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Well known pre-preg materials used in the PCB industry are FR-2 (phenolic cotton paper), FR-3 (cotton paper and epoxy), FR-4 (woven glass and epoxy), FR-5 (woven glass and epoxy), FR-6 (matte glass and polyester), G-10 (woven glass and epoxy), CEM-1 (cotton paper and epoxy), CEM-2 (cotton paper and epoxy), CEM-3 (non-woven glass and epoxy), CEM-4 (woven glass and epoxy), CEM-5 (woven glass and polyester). Thermal expansion is an important consideration especially with ball grid array (BGA) and naked die technologies, and glass fiber offers the best dimensional stability. FR-4 is by far the most common material used today. The board stock with unetched copper on it is called "copper-clad laminate". With decreasing size of board features and increasing frequencies, small non-homogeneities like uneven distribution of fiberglass or other filler, thickness variations, and bubbles in the resin matrix, and the associated local variations in the dielectric constant, are gaining importance. The circuit-board substrates are usually dielectric composite materials. The composites contain a matrix (usually an epoxy resin) and a reinforcement (usually a woven, sometimes non-woven, glass fibers, sometimes even paper), and in some cases a filler is added to the resin (e.g. ceramics; titanate ceramics can be used to increase the dielectric constant). The reinforcement type defines two major classes of materials: woven and non-woven. Woven reinforcements are cheaper, but the high dielectric constant of glass may not be favorable for many higher-frequency applications. The spatially non-homogeneous structure also introduces local variations in electrical parameters, due to different resin/glass ratio at different areas of the weave pattern. Non-woven reinforcements, or materials with low or no reinforcement, are more expensive but more suitable for some RF/analog applications. The substrates are characterized by several key parameters, chiefly thermomechanical (glass transition temperature, tensile strength, shear strength, thermal expansion), electrical (dielectric constant, loss tangent, dielectric breakdown voltage, leakage current, tracking resistance...), and others (e.g. moisture absorption). At the glass transition temperature the resin in the composite softens and significantly increases thermal expansion; exceeding Tg then exerts mechanical overload on the board components - e.g. the joints and the vias. Below Tg the thermal expansion of the resin roughly matches copper and glass, above it gets significantly higher. As the reinforcement and copper confine the board along the plane, virtually all volume expansion projects to the thickness and stresses the plated-through holes. Repeated soldering or other exposition to higher temperatures can cause failure of the plating, especially with thicker boards; thick boards therefore require a matrix with a high Tg. The materials used determine the substrate's dielectric constant. This constant is also dependent on frequency, usually decreasing with frequency. As this constant determines the signal propagation speed, frequency dependence introduces phase distortion in wideband applications; as flat a dielectric constant vs frequency characteristics as is achievable is important here. The impedance of transmission lines decreases with frequency, therefore faster edges of signals reflect more than slower ones. Dielectric breakdown voltage determines the maximum voltage gradient the material can be subjected to before suffering a breakdown (conduction, or arcing, through the dielectric). Tracking resistance determines how the material resists high voltage electrical discharges creeping over the board surface. Loss tangent determines how much of the electromagnetic energy from the signals in the conductors is absorbed in the board material. This factor is important for high frequencies. Low-loss materials are more expensive. Choosing unnecessarily low-loss material is a common engineering error in high-frequency digital design; it increases the cost of the boards without a corresponding benefit. Signal degradation by loss tangent and dielectric constant can be easily assessed by an eye pattern. Moisture absorption occurs when the material is exposed to high humidity or water. Both the resin and the reinforcement may absorb water; water also may be soaked by capillary forces through voids in the materials and along the reinforcement. Epoxies of the FR-4 materials are not too susceptible, with absorption of only 0.15%. Teflon has very low absorption of 0.01%. Polyimides and cyanate esters, on the other side, suffer from high water absorption. Absorbed water can lead to significant degradation of key parameters; it impairs tracking resistance, breakdown voltage, and dielectric parameters. Relative dielectric constant of water is about 73, compared to about 4 for common circuit board materials. Absorbed moisture can also vaporize on heating, as during soldering, and cause cracking and delamination, the same effect responsible for "popcorning" damage on wet packaging of electronic parts. Careful baking of the substrates may be required to dry them prior to soldering. Often encountered materials: Less-often encountered materials: Copper thickness of PCBs can be specified directly or as the weight of copper per area (in ounce per square foot) which is easier to measure. One ounce per square foot is 1.344 mils or 34 micrometers thickness (0.001344 inches). Heavy copper is a layer exceeding three ounces of copper per ft2, or approximately 4.2 mils (105 μm) (0.0042 inches) thick. Heavy copper layers are used for high current or to help dissipate heat.[citation needed] On the common FR-4 substrates, 1 oz copper per ft2 (35 μm) is the most common thickness; 2 oz (70 μm) and 0.5 oz (17.5 μm) thickness is often an option. Less common are 12 and 105 μm, 9 μm is sometimes available on some substrates. Flexible substrates typically have thinner metalization. Metal-core boards for high power devices commonly use thicker copper; 35 μm is usual but also 140 and 400 μm can be encountered. In the US, copper foil thickness is specified in units of ounces per square foot (oz/ft2), commonly referred to simply as ounce. Common thicknesses are 1/2 oz/ft2 (150 g/m2), 1 oz/ft2 (300 g/m2), 2 oz/ft2 (600 g/m2), and 3 oz/ft2 (900 g/m2). These work out to thicknesses of 17.05 μm (0.67 thou), 34.1 μm (1.34 thou), 68.2 μm (2.68 thou), and 102.3 μm (4.02 thou), respectively. 1/2 oz/ft2 foil is not widely used as a finished copper weight, but is used for outer layers when plating for through holes will increase the finished copper weight Some PCB manufacturers refer to 1 oz/ft2 copper foil as having a thickness of 35 μm (may also be referred to as 35 μ, 35 micron, or 35 mic). Manufacturing Printed circuit board manufacturing involves manufacturing bare printed circuit boards and then populating them with electronic components. In large-scale board manufacturing, multiple PCBs are grouped on a single panel for efficient processing. After assembly, they are separated (depaneled). Types A minimal PCB for a single component, used for prototyping, is called a breakout board. The purpose of a breakout board is to "break out" the leads of a component on separate terminals so that manual connections to them can be made easily. Breakout boards are especially used for surface-mount components or any components with fine lead pitch. Advanced PCBs may contain components embedded in the substrate, such as capacitors and integrated circuits, to reduce the amount of space taken up by components on the surface of the PCB while improving electrical characteristics. Multiwire is a patented technique of interconnection which uses machine-routed insulated wires embedded in a non-conducting matrix (often plastic resin). It was used during the 1980s and 1990s. As of 2010,[update] Multiwire is still available through Hitachi. Since it was quite easy to stack interconnections (wires) inside the embedding matrix, the approach allowed designers to forget completely about the routing of wires (usually a time-consuming operation of PCB design): Anywhere the designer needs a connection, the machine will draw a wire in a straight line from one location/pin to another. This led to very short design times (no complex algorithms to use even for high density designs) as well as reduced crosstalk (which is worse when wires run parallel to each other—which almost never happens in Multiwire), though the cost is too high to compete with cheaper PCB technologies when large quantities are needed. Corrections can be made to a Multiwire board layout more easily than to a PCB layout. Before the advent of integrated circuits, cordwood construction allowed the highest possible component packing density. The construction method was used with wire-ended components in applications where space was at a premium (such as fuzes, missile guidance, and telemetry systems) and in the high-speed computers of the day, where short traces were important. In cordwood construction, axial-leaded components were mounted between two parallel planes. The name comes from the way axial-lead components (capacitors, resistors, coils, and diodes) are stacked in parallel rows and columns, like a stack of firewood. The components were either soldered together with jumper wire or they were connected to other components by thin nickel ribbon welded at right angles onto the component leads. Some versions of cordwood construction used soldered single-sided PCBs as the interconnection method (as pictured), allowing the use of normal-leaded components at the cost of being difficult to remove the boards or replace any component that is not at the edge.[citation needed] Cordwood construction was replaced with multi-layer board, SMD and ICs. A Flexible Printed Circuit Board (FPCB) is a thin, lightweight circuit made from flexible materials like polyimide. It can bend or fold while maintaining reliable electrical connections and is commonly used in compact electronic devices such as smartphones, wearables, and medical equipment.[citation needed] Uses Printed circuit boards have been used as an alternative to their typical use for electronic and biomedical engineering thanks to the versatility of their layers, especially the copper layer. PCB layers have been used to fabricate sensors, such as capacitive pressure sensors and accelerometers, actuators such as microvalves and microheaters, as well as platforms of sensors and actuators for Lab-on-a-chip (LoC), for example to perform polymerase chain reaction (PCR), and fuel cells, to name a few. Repair Manufacturers may not support component-level repair of printed circuit boards because of the relatively low cost to replace compared with the time and cost of troubleshooting to a component level. In board-level repair, the technician identifies the board (PCA) on which the fault resides and replaces it. This shift is economically efficient from a manufacturer's point of view but is also materially wasteful, as a circuit board with hundreds of functional components may be discarded and replaced due to the failure of one minor and inexpensive part, such as a resistor or capacitor, and this practice is a significant contributor to the problem of e-waste. Legislation In many countries (including all European Single Market participants, the United Kingdom, Turkey, and China), legislation restricts the use of lead, cadmium, and mercury in electrical equipment. PCBs sold in such countries must therefore use lead-free manufacturing processes and lead-free solder, and attached components must themselves be compliant. Safety Standard UL 796 covers component safety requirements for printed wiring boards for use as components in devices or appliances. Testing analyzes characteristics such as flammability, maximum operating temperature, electrical tracking, heat deflection, and direct support of live electrical parts. See also References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Elon_Musk#cite_note-198] | [TOKENS: 10515] |
Contents Elon Musk Elon Reeve Musk (/ˈiːlɒn/ EE-lon; born June 28, 1971) is a businessman and entrepreneur known for his leadership of Tesla, SpaceX, Twitter, and xAI. Musk has been the wealthiest person in the world since 2025; as of February 2026,[update] Forbes estimates his net worth to be around US$852 billion. Born into a wealthy family in Pretoria, South Africa, Musk emigrated in 1989 to Canada; he has Canadian citizenship since his mother was born there. He received bachelor's degrees in 1997 from the University of Pennsylvania before moving to California to pursue business ventures. In 1995, Musk co-founded the software company Zip2. Following its sale in 1999, he co-founded X.com, an online payment company that later merged to form PayPal, which was acquired by eBay in 2002. Musk also became an American citizen in 2002. In 2002, Musk founded the space technology company SpaceX, becoming its CEO and chief engineer; the company has since led innovations in reusable rockets and commercial spaceflight. Musk joined the automaker Tesla as an early investor in 2004 and became its CEO and product architect in 2008; it has since become a leader in electric vehicles. In 2015, he co-founded OpenAI to advance artificial intelligence (AI) research, but later left; growing discontent with the organization's direction and their leadership in the AI boom in the 2020s led him to establish xAI, which became a subsidiary of SpaceX in 2026. In 2022, he acquired the social network Twitter, implementing significant changes, and rebranding it as X in 2023. His other businesses include the neurotechnology company Neuralink, which he co-founded in 2016, and the tunneling company the Boring Company, which he founded in 2017. In November 2025, a Tesla pay package worth $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Musk was the largest donor in the 2024 U.S. presidential election, where he supported Donald Trump. After Trump was inaugurated as president in early 2025, Musk served as Senior Advisor to the President and as the de facto head of the Department of Government Efficiency (DOGE). After a public feud with Trump, Musk left the Trump administration and returned to managing his companies. Musk is a supporter of global far-right figures, causes, and political parties. His political activities, views, and statements have made him a polarizing figure. Musk has been criticized for COVID-19 misinformation, promoting conspiracy theories, and affirming antisemitic, racist, and transphobic comments. His acquisition of Twitter was controversial due to a subsequent increase in hate speech and the spread of misinformation on the service, following his pledge to decrease censorship. His role in the second Trump administration attracted public backlash, particularly in response to DOGE. The emails he sent to Jeffrey Epstein are included in the Epstein files, which were published between 2025–26 and became a topic of worldwide debate. Early life Elon Reeve Musk was born on June 28, 1971, in Pretoria, South Africa's administrative capital. He is of British and Pennsylvania Dutch ancestry. His mother, Maye (née Haldeman), is a model and dietitian born in Saskatchewan, Canada, and raised in South Africa. Musk therefore holds both South African and Canadian citizenship from birth. His father, Errol Musk, is a South African electromechanical engineer, pilot, sailor, consultant, emerald dealer, and property developer, who partly owned a rental lodge at Timbavati Private Nature Reserve. His maternal grandfather, Joshua N. Haldeman, who died in a plane crash when Elon was a toddler, was an American-born Canadian chiropractor, aviator and political activist in the technocracy movement who moved to South Africa in 1950. Elon has a younger brother, Kimbal, a younger sister, Tosca, and four paternal half-siblings. Musk was baptized as a child in the Anglican Church of Southern Africa. Despite both Elon and Errol previously stating that Errol was a part owner of a Zambian emerald mine, in 2023, Errol recounted that the deal he made was to receive "a portion of the emeralds produced at three small mines". Errol was elected to the Pretoria City Council as a representative of the anti-apartheid Progressive Party and has said that his children shared their father's dislike of apartheid. After his parents divorced in 1979, Elon, aged around 9, chose to live with his father because Errol Musk had an Encyclopædia Britannica and a computer. Elon later regretted his decision and became estranged from his father. Elon has recounted trips to a wilderness school that he described as a "paramilitary Lord of the Flies" where "bullying was a virtue" and children were encouraged to fight over rations. In one incident, after an altercation with a fellow pupil, Elon was thrown down concrete steps and beaten severely, leading to him being hospitalized for his injuries. Elon described his father berating him after he was discharged from the hospital. Errol denied berating Elon and claimed, "The [other] boy had just lost his father to suicide, and Elon had called him stupid. Elon had a tendency to call people stupid. How could I possibly blame that child?" Elon was an enthusiastic reader of books, and had attributed his success in part to having read The Lord of the Rings, the Foundation series, and The Hitchhiker's Guide to the Galaxy. At age ten, he developed an interest in computing and video games, teaching himself how to program from the VIC-20 user manual. At age twelve, Elon sold his BASIC-based game Blastar to PC and Office Technology magazine for approximately $500 (equivalent to $1,600 in 2025). Musk attended Waterkloof House Preparatory School, Bryanston High School, and then Pretoria Boys High School, where he graduated. Musk was a decent but unexceptional student, earning a 61/100 in Afrikaans and a B on his senior math certification. Musk applied for a Canadian passport through his Canadian-born mother to avoid South Africa's mandatory military service, which would have forced him to participate in the apartheid regime, as well as to ease his path to immigration to the United States. While waiting for his application to be processed, he attended the University of Pretoria for five months. Musk arrived in Canada in June 1989, connected with a second cousin in Saskatchewan, and worked odd jobs, including at a farm and a lumber mill. In 1990, he entered Queen's University in Kingston, Ontario. Two years later, he transferred to the University of Pennsylvania, where he studied until 1995. Although Musk has said that he earned his degrees in 1995, the University of Pennsylvania did not award them until 1997 – a Bachelor of Arts in physics and a Bachelor of Science in economics from the university's Wharton School. He reportedly hosted large, ticketed house parties to help pay for tuition, and wrote a business plan for an electronic book-scanning service similar to Google Books. In 1994, Musk held two internships in Silicon Valley: one at energy storage startup Pinnacle Research Institute, which investigated electrolytic supercapacitors for energy storage, and another at Palo Alto–based startup Rocket Science Games. In 1995, he was accepted to a graduate program in materials science at Stanford University, but did not enroll. Musk decided to join the Internet boom of the 1990s, applying for a job at Netscape, to which he reportedly never received a response. The Washington Post reported that Musk lacked legal authorization to remain and work in the United States after failing to enroll at Stanford. In response, Musk said he was allowed to work at that time and that his student visa transitioned to an H1-B. According to numerous former business associates and shareholders, Musk said he was on a student visa at the time. Business career In 1995, Musk, his brother Kimbal, and Greg Kouri founded the web software company Zip2 with funding from a group of angel investors. They housed the venture at a small rented office in Palo Alto. Replying to Rolling Stone, Musk denounced the notion that they started their company with funds borrowed from Errol Musk, but in a tweet, he recognized that his father contributed 10% of a later funding round. The company developed and marketed an Internet city guide for the newspaper publishing industry, with maps, directions, and yellow pages. According to Musk, "The website was up during the day and I was coding it at night, seven days a week, all the time." To impress investors, Musk built a large plastic structure around a standard computer to create the impression that Zip2 was powered by a small supercomputer. The Musk brothers obtained contracts with The New York Times and the Chicago Tribune, and persuaded the board of directors to abandon plans for a merger with CitySearch. Musk's attempts to become CEO were thwarted by the board. Compaq acquired Zip2 for $307 million in cash in February 1999 (equivalent to $590,000,000 in 2025), and Musk received $22 million (equivalent to $43,000,000 in 2025) for his 7-percent share. In 1999, Musk co-founded X.com, an online financial services and e-mail payment company. The startup was one of the first federally insured online banks, and, in its initial months of operation, over 200,000 customers joined the service. The company's investors regarded Musk as inexperienced and replaced him with Intuit CEO Bill Harris by the end of the year. The following year, X.com merged with online bank Confinity to avoid competition. Founded by Max Levchin and Peter Thiel, Confinity had its own money-transfer service, PayPal, which was more popular than X.com's service. Within the merged company, Musk returned as CEO. Musk's preference for Microsoft software over Unix created a rift in the company and caused Thiel to resign. Due to resulting technological issues and lack of a cohesive business model, the board ousted Musk and replaced him with Thiel in 2000.[b] Under Thiel, the company focused on the PayPal service and was renamed PayPal in 2001. In 2002, PayPal was acquired by eBay for $1.5 billion (equivalent to $2,700,000,000 in 2025) in stock, of which Musk—the largest shareholder with 11.72% of shares—received $175.8 million (equivalent to $320,000,000 in 2025). In 2017, Musk purchased the domain X.com from PayPal for an undisclosed amount, stating that it had sentimental value. In 2001, Musk became involved with the nonprofit Mars Society and discussed funding plans to place a growth-chamber for plants on Mars. Seeking a way to launch the greenhouse payloads into space, Musk made two unsuccessful trips to Moscow to purchase intercontinental ballistic missiles (ICBMs) from Russian companies NPO Lavochkin and Kosmotras. Musk instead decided to start a company to build affordable rockets. With $100 million of his early fortune, (equivalent to $180,000,000 in 2025) Musk founded SpaceX in May 2002 and became the company's CEO and Chief Engineer. SpaceX attempted its first launch of the Falcon 1 rocket in 2006. Although the rocket failed to reach Earth orbit, it was awarded a Commercial Orbital Transportation Services program contract from NASA, then led by Mike Griffin. After two more failed attempts that nearly caused Musk to go bankrupt, SpaceX succeeded in launching the Falcon 1 into orbit in 2008. Later that year, SpaceX received a $1.6 billion NASA contract (equivalent to $2,400,000,000 in 2025) for Falcon 9-launched Dragon spacecraft flights to the International Space Station (ISS), replacing the Space Shuttle after its 2011 retirement. In 2012, the Dragon vehicle docked with the ISS, a first for a commercial spacecraft. Working towards its goal of reusable rockets, in 2015 SpaceX successfully landed the first stage of a Falcon 9 on a land platform. Later landings were achieved on autonomous spaceport drone ships, an ocean-based recovery platform. In 2018, SpaceX launched the Falcon Heavy; the inaugural mission carried Musk's personal Tesla Roadster as a dummy payload. Since 2019, SpaceX has been developing Starship, a reusable, super heavy-lift launch vehicle intended to replace the Falcon 9 and Falcon Heavy. In 2020, SpaceX launched its first crewed flight, the Demo-2, becoming the first private company to place astronauts into orbit and dock a crewed spacecraft with the ISS. In 2024, NASA awarded SpaceX an $843 million (equivalent to $865,000,000 in 2025) contract to build a spacecraft that NASA will use to deorbit the ISS at the end of its lifespan. In 2015, SpaceX began development of the Starlink constellation of low Earth orbit satellites to provide satellite Internet access. After the launch of prototype satellites in 2018, the first large constellation was deployed in May 2019. As of May 2025[update], over 7,600 Starlink satellites are operational, comprising 65% of all operational Earth satellites. The total cost of the decade-long project to design, build, and deploy the constellation was estimated by SpaceX in 2020 to be $10 billion (equivalent to $12,000,000,000 in 2025).[c] During the Russian invasion of Ukraine, Musk provided free Starlink service to Ukraine, permitting Internet access and communication at a yearly cost to SpaceX of $400 million (equivalent to $440,000,000 in 2025). However, Musk refused to block Russian state media on Starlink. In 2023, Musk denied Ukraine's request to activate Starlink over Crimea to aid an attack against the Russian navy, citing fears of a nuclear response. Tesla, Inc., originally Tesla Motors, was incorporated in July 2003 by Martin Eberhard and Marc Tarpenning. Both men played active roles in the company's early development prior to Musk's involvement. Musk led the Series A round of investment in February 2004; he invested $6.35 million (equivalent to $11,000,000 in 2025), became the majority shareholder, and joined Tesla's board of directors as chairman. Musk took an active role within the company and oversaw Roadster product design, but was not deeply involved in day-to-day business operations. Following a series of escalating conflicts in 2007 and the 2008 financial crisis, Eberhard was ousted from the firm.[page needed] Musk assumed leadership of the company as CEO and product architect in 2008. A 2009 lawsuit settlement with Eberhard designated Musk as a Tesla co-founder, along with Tarpenning and two others. Tesla began delivery of the Roadster, an electric sports car, in 2008. With sales of about 2,500 vehicles, it was the first mass production all-electric car to use lithium-ion battery cells. Under Musk, Tesla has since launched several well-selling electric vehicles, including the four-door sedan Model S (2012), the crossover Model X (2015), the mass-market sedan Model 3 (2017), the crossover Model Y (2020), and the pickup truck Cybertruck (2023). In May 2020, Musk resigned as chairman of the board as part of the settlement of a lawsuit from the SEC over him tweeting that funding had been "secured" for potentially taking Tesla private. The company has also constructed multiple lithium-ion battery and electric vehicle factories, called Gigafactories. Since its initial public offering in 2010, Tesla stock has risen significantly; it became the most valuable carmaker in summer 2020, and it entered the S&P 500 later that year. In October 2021, it reached a market capitalization of $1 trillion (equivalent to $1,200,000,000,000 in 2025), the sixth company in U.S. history to do so. Musk provided the initial concept and financial capital for SolarCity, which his cousins Lyndon and Peter Rive founded in 2006. By 2013, SolarCity was the second largest provider of solar power systems in the United States. In 2014, Musk promoted the idea of SolarCity building an advanced production facility in Buffalo, New York, triple the size of the largest solar plant in the United States. Construction of the factory started in 2014 and was completed in 2017. It operated as a joint venture with Panasonic until early 2020. Tesla acquired SolarCity for $2 billion in 2016 (equivalent to $2,700,000,000 in 2025) and merged it with its battery unit to create Tesla Energy. The deal's announcement resulted in a more than 10% drop in Tesla's stock price; at the time, SolarCity was facing liquidity issues. Multiple shareholder groups filed a lawsuit against Musk and Tesla's directors, stating that the purchase of SolarCity was done solely to benefit Musk and came at the expense of Tesla and its shareholders. Tesla directors settled the lawsuit in January 2020, leaving Musk the sole remaining defendant. Two years later, the court ruled in Musk's favor. In 2016, Musk co-founded Neuralink, a neurotechnology startup, with an investment of $100 million. Neuralink aims to integrate the human brain with artificial intelligence (AI) by creating devices that are embedded in the brain. Such technology could enhance memory or allow the devices to communicate with software. The company also hopes to develop devices to treat neurological conditions like spinal cord injuries. In 2022, Neuralink announced that clinical trials would begin by the end of the year. In September 2023, the Food and Drug Administration approved Neuralink to initiate six-year human trials. Neuralink has conducted animal testing on macaques at the University of California, Davis. In 2021, the company released a video in which a macaque played the video game Pong via a Neuralink implant. The company's animal trials—which have caused the deaths of some monkeys—have led to claims of animal cruelty. The Physicians Committee for Responsible Medicine has alleged that Neuralink violated the Animal Welfare Act. Employees have complained that pressure from Musk to accelerate development has led to botched experiments and unnecessary animal deaths. In 2022, a federal probe was launched into possible animal welfare violations by Neuralink.[needs update] In 2017, Musk founded the Boring Company to construct tunnels; he also revealed plans for specialized, underground, high-occupancy vehicles that could travel up to 150 miles per hour (240 km/h) and thus circumvent above-ground traffic in major cities. Early in 2017, the company began discussions with regulatory bodies and initiated construction of a 30-foot (9.1 m) wide, 50-foot (15 m) long, and 15-foot (4.6 m) deep "test trench" on the premises of SpaceX's offices, as that required no permits. The Los Angeles tunnel, less than two miles (3.2 km) in length, debuted to journalists in 2018. It used Tesla Model Xs and was reported to be a rough ride while traveling at suboptimal speeds. Two tunnel projects announced in 2018, in Chicago and West Los Angeles, have been canceled. A tunnel beneath the Las Vegas Convention Center was completed in early 2021. Local officials have approved further expansions of the tunnel system. April 14, 2022 In early 2017, Musk expressed interest in buying Twitter and had questioned the platform's commitment to freedom of speech. By 2022, Musk had reached 9.2% stake in the company, making him the largest shareholder.[d] Musk later agreed to a deal that would appoint him to Twitter's board of directors and prohibit him from acquiring more than 14.9% of the company. Days later, Musk made a $43 billion offer to buy Twitter. By the end of April Musk had successfully concluded his bid for approximately $44 billion. This included approximately $12.5 billion in loans and $21 billion in equity financing. Having backtracked on his initial decision, Musk bought the company on October 27, 2022. Immediately after the acquisition, Musk fired several top Twitter executives including CEO Parag Agrawal; Musk became the CEO instead. Under Elon Musk, Twitter instituted monthly subscriptions for a "blue check", and laid off a significant portion of the company's staff. Musk lessened content moderation and hate speech also increased on the platform after his takeover. In late 2022, Musk released internal documents relating to Twitter's moderation of Hunter Biden's laptop controversy in the lead-up to the 2020 presidential election. Musk also promised to step down as CEO after a Twitter poll, and five months later, Musk stepped down as CEO and transitioned his role to executive chairman and chief technology officer (CTO). Despite Musk stepping down as CEO, X continues to struggle with challenges such as viral misinformation, hate speech, and antisemitism controversies. Musk has been accused of trying to silence some of his critics such as Twitch streamer Asmongold, who criticized him during one of his streams. Musk has been accused of removing their accounts' blue checkmarks, which hinders visibility and is considered a form of shadow banning, or suspending their accounts without justification. Other activities In August 2013, Musk announced plans for a version of a vactrain, and assigned engineers from SpaceX and Tesla to design a transport system between Greater Los Angeles and the San Francisco Bay Area, at an estimated cost of $6 billion. Later that year, Musk unveiled the concept, dubbed the Hyperloop, intended to make travel cheaper than any other mode of transport for such long distances. In December 2015, Musk co-founded OpenAI, a not-for-profit artificial intelligence (AI) research company aiming to develop artificial general intelligence, intended to be safe and beneficial to humanity. Musk pledged $1 billion of funding to the company, and initially gave $50 million. In 2018, Musk left the OpenAI board. Since 2018, OpenAI has made significant advances in machine learning. In July 2023, Musk launched the artificial intelligence company xAI, which aims to develop a generative AI program that competes with existing offerings like OpenAI's ChatGPT. Musk obtained funding from investors in SpaceX and Tesla, and xAI hired engineers from Google and OpenAI. December 16, 2022 Musk uses a private jet owned by Falcon Landing LLC, a SpaceX-linked company, and acquired a second jet in August 2020. His heavy use of the jets and the consequent fossil fuel usage have received criticism. Musk's flight usage is tracked on social media through ElonJet. In December 2022, Musk banned the ElonJet account on Twitter, and made temporary bans on the accounts of journalists that posted stories regarding the incident, including Donie O'Sullivan, Keith Olbermann, and journalists from The New York Times, The Washington Post, CNN, and The Intercept. In October 2025, Musk's company xAI launched Grokipedia, an AI-generated online encyclopedia that he promoted as an alternative to Wikipedia. Articles on Grokipedia are generated and reviewed by xAI's Grok chatbot. Media coverage and academic analysis described Grokipedia as frequently reusing Wikipedia content but framing contested political and social topics in line with Musk's own views and right-wing narratives. A study by Cornell University researchers and NBC News stated that Grokipedia cites sources that are blacklisted or considered "generally unreliable" on Wikipedia, for example, the conspiracy site Infowars and the neo-Nazi forum Stormfront. Wired, The Guardian and Time criticized Grokipedia for factual errors and for presenting Musk himself in unusually positive terms while downplaying controversies. Politics Musk is an outlier among business leaders who typically avoid partisan political advocacy. Musk was a registered independent voter when he lived in California. Historically, he has donated to both Democrats and Republicans, many of whom serve in states in which he has a vested interest. Since 2022, his political contributions have mostly supported Republicans, with his first vote for a Republican going to Mayra Flores in the 2022 Texas's 34th congressional district special election. In 2024, he started supporting international far-right political parties, activists, and causes, and has shared misinformation and numerous conspiracy theories. Since 2024, his views have been generally described as right-wing. Musk supported Barack Obama in 2008 and 2012, Hillary Clinton in 2016, Joe Biden in 2020, and Donald Trump in 2024. In the 2020 Democratic Party presidential primaries, Musk endorsed candidate Andrew Yang and expressed support for Yang's proposed universal basic income, and endorsed Kanye West's 2020 presidential campaign. In 2021, Musk publicly expressed opposition to the Build Back Better Act, a $3.5 trillion legislative package endorsed by Joe Biden that ultimately failed to pass due to unanimous opposition from congressional Republicans and several Democrats. In 2022, gave over $50 million to Citizens for Sanity, a conservative political action committee. In 2023, he supported Republican Ron DeSantis for the 2024 U.S. presidential election, giving $10 million to his campaign, and hosted DeSantis's campaign announcement on a Twitter Spaces event. From June 2023 to January 2024, Musk hosted a bipartisan set of X Spaces with Republican and Democratic candidates, including Robert F. Kennedy Jr., Vivek Ramaswamy, and Dean Phillips. In October 2025, former vice-president Kamala Harris commented that it was a mistake from the Democratic side to not invite Musk to a White House electric vehicle event organized in August 2021 and featuring executives from General Motors, Ford and Stellantis, despite Tesla being "the major American manufacturer of extraordinary innovation in this space." Fortune remarked that this was a nod to United Auto Workers and organized labor. Harris said presidents should put aside political loyalties when it came to recognizing innovation, and guessed that the non-invitation impacted Musk's perspective. Fortune noted that, at the time, Musk said, "Yeah, seems odd that Tesla wasn't invited." A month later, he criticized Biden as "not the friendliest administration." Jacob Silverman, author of the book Gilded Rage: Elon Musk and the Radicalization of Silicon Valley, said that the tech industry represented by Musk, Thiel, Andreessen and other capitalists, actually flourished under Biden, but the tech leaders chose Trump for their common ground on cultural issues. By early 2024, Musk had become a vocal and financial supporter of Donald Trump. In July 2024, minutes after the attempted assassination of Donald Trump, Musk endorsed him for president saying; "I fully endorse President Trump and hope for his rapid recovery." During the presidential campaign, Musk joined Trump on stage at a campaign rally, and during the campaign promoted conspiracy theories and falsehoods about Democrats, election fraud and immigration, in support of Trump. Musk was the largest individual donor of the 2024 election. In 2025, Musk contributed $19 million to the Wisconsin Supreme Court race, hoping to influence the state's future redistricting efforts and its regulations governing car manufacturers and dealers. In 2023, Musk said he shunned the World Economic Forum because it was boring. The organization commented that they had not invited him since 2015. He has participated in Dialog, dubbed "Tech Bilderberg" and organized by Peter Thiel and Auren Hoffman, though. Musk's international political actions and comments have come under increasing scrutiny and criticism, especially from the governments and leaders of France, Germany, Norway, Spain and the United Kingdom, particularly due to his position in the U.S. government as well as ownership of X. An NBC News analysis found he had boosted far-right political movements to cut immigration and curtail regulation of business in at least 18 countries on six continents since 2023. During his speech after the second inauguration of Donald Trump, Musk twice made a gesture interpreted by many as a Nazi or a fascist Roman salute.[e] He thumped his right hand over his heart, fingers spread wide, and then extended his right arm out, emphatically, at an upward angle, palm down and fingers together. He then repeated the gesture to the crowd behind him. As he finished the gestures, he said to the crowd, "My heart goes out to you. It is thanks to you that the future of civilization is assured." It was widely condemned as an intentional Nazi salute in Germany, where making such gestures is illegal. The Anti-Defamation League said it was not a Nazi salute, but other Jewish organizations disagreed and condemned the salute. American public opinion was divided on partisan lines as to whether it was a fascist salute. Musk dismissed the accusations of Nazi sympathies, deriding them as "dirty tricks" and a "tired" attack. Neo-Nazi and white supremacist groups celebrated it as a Nazi salute. Multiple European political parties demanded that Musk be banned from entering their countries. The concept of DOGE emerged in a discussion between Musk and Donald Trump, and in August 2024, Trump committed to giving Musk an advisory role, with Musk accepting the offer. In November and December 2024, Musk suggested that the organization could help to cut the U.S. federal budget, consolidate the number of federal agencies, and eliminate the Consumer Financial Protection Bureau, and that its final stage would be "deleting itself". In January 2025, the organization was created by executive order, and Musk was designated a "special government employee". Musk led the organization and was a senior advisor to the president, although his official role is not clear. In sworn statement during a lawsuit, the director of the White House Office of Administration stated that Musk "is not an employee of the U.S. DOGE Service or U.S. DOGE Service Temporary Organization", "is not the U.S. DOGE Service administrator", and has "no actual or formal authority to make government decisions himself". Trump said two days later that he had put Musk in charge of DOGE. A federal judge has ruled that Musk acted as the de facto leader of DOGE. Musk's role in the second Trump administration, particularly in response to DOGE, has attracted public backlash. He was criticized for his treatment of federal government employees, including his influence over the mass layoffs of the federal workforce. He has prioritized secrecy within the organization and has accused others of violating privacy laws. A Senate report alleged that Musk could avoid up to $2 billion in legal liability as a result of DOGE's actions. In May 2025, Bill Gates accused Musk of "killing the world's poorest children" through his cuts to USAID, which modeling by Boston University estimated had resulted in 300,000 deaths by this time, most of them of children. By November 2025, the estimated death toll had increased to 400,000 children and 200,000 adults. Musk announced on May 28, 2025, that he would depart from the Trump administration as planned when the special government employee's 130 day deadline expired, with a White House official confirming that Musk's offboarding from the Trump administration was already underway. His departure was officially confirmed during a joint Oval Office press conference with Trump on May 30, 2025. @realDonaldTrump is in the Epstein files. That is the real reason they have not been made public. June 5, 2025 After leaving office, Musk criticized the Trump administration's Big Beautiful Bill, calling it a "disgusting abomination" due to its provisions increasing the deficit. A feud began between Musk and Trump, with its most notable event being Musk alleging Trump had ties to sex offender Jeffrey Epstein on X (formerly Twitter) on June 5, 2025. Trump responded on Truth Social stating that Musk went "CRAZY" after the "EV Mandate" was purportedly taken away and threatened to cut Musk's government contracts. Musk then called for a third Trump impeachment. The next day, Trump stated that he did not wish to reconcile with Musk, and added that Musk would face "very serious consequences" if he funds Democratic candidates. On June 11, Musk publicly apologized for the tweets against Trump, saying they "went too far". Views November 6, 2022 Rejecting the conservative label, Musk has described himself as a political moderate, even as his views have become more right-wing over time. His views have been characterized as libertarian and far-right, and after his involvement in European politics, they have received criticism from world leaders such as Emmanuel Macron and Olaf Scholz. Within the context of American politics, Musk supported Democratic candidates up until 2022, at which point he voted for a Republican for the first time. He has stated support for universal basic income, gun rights, freedom of speech, a tax on carbon emissions, and H-1B visas. Musk has expressed concern about issues such as artificial intelligence (AI) and climate change, and has been a critic of wealth tax, short-selling, and government subsidies. An immigrant himself, Musk has been accused of being anti-immigration, and regularly blames immigration policies for illegal immigration. He is also a pronatalist who believes population decline is the biggest threat to civilization, and identifies as a cultural Christian. Musk has long been an advocate for space colonization, especially the colonization of Mars. He has repeatedly pushed for humanity colonizing Mars, in order to become an interplanetary species and lower the risks of human extinction. Musk has promoted conspiracy theories and made controversial statements that have led to accusations of racism, sexism, antisemitism, transphobia, disseminating disinformation, and support of white pride. While describing himself as a "pro-Semite", his comments regarding George Soros and Jewish communities have been condemned by the Anti-Defamation League and the Biden White House. Musk was criticized during the COVID-19 pandemic for making unfounded epidemiological claims, defying COVID-19 lockdowns restrictions, and supporting the Canada convoy protest against vaccine mandates. He has amplified false claims of white genocide in South Africa. Musk has been critical of Israel's actions in the Gaza Strip during the Gaza war, praised China's economic and climate goals, suggested that Taiwan and China should resolve cross-strait relations, and was described as having a close relationship with the Chinese government. In Europe, Musk expressed support for Ukraine in 2022 during the Russian invasion, recommended referendums and peace deals on the annexed Russia-occupied territories, and supported the far-right Alternative for Germany political party in 2024. Regarding British politics, Musk blamed the 2024 UK riots on mass migration and open borders, criticized Prime Minister Keir Starmer for what he described as a "two-tier" policing system, and was subsequently attacked as being responsible for spreading misinformation and amplifying the far-right. He has also voiced his support for far-right activist Tommy Robinson and pledged electoral support for Reform UK. In February 2026, Musk described Spanish Prime Minister Pedro Sánchez as a "tyrant" following Sánchez's proposal to prohibit minors under the age of 16 from accessing social media platforms. Legal affairs In 2018, Musk was sued by the U.S. Securities and Exchange Commission (SEC) for a tweet stating that funding had been secured for potentially taking Tesla private.[f] The securities fraud lawsuit characterized the tweet as false, misleading, and damaging to investors, and sought to bar Musk from serving as CEO of publicly traded companies. Two days later, Musk settled with the SEC, without admitting or denying the SEC's allegations. As a result, Musk and Tesla were fined $20 million each, and Musk was forced to step down for three years as Tesla chairman but was able to remain as CEO. Shareholders filed a lawsuit over the tweet, and in February 2023, a jury found Musk and Tesla not liable. Musk has stated in interviews that he does not regret posting the tweet that triggered the SEC investigation. In 2019, Musk stated in a tweet that Tesla would build half a million cars that year. The SEC reacted by asking a court to hold him in contempt for violating the terms of the 2018 settlement agreement. A joint agreement between Musk and the SEC eventually clarified the previous agreement details, including a list of topics about which Musk needed preclearance. In 2020, a judge blocked a lawsuit that claimed a tweet by Musk regarding Tesla stock price ("too high imo") violated the agreement. Freedom of Information Act (FOIA)-released records showed that the SEC concluded Musk had subsequently violated the agreement twice by tweeting regarding "Tesla's solar roof production volumes and its stock price". In October 2023, the SEC sued Musk over his refusal to testify a third time in an investigation into whether he violated federal law by purchasing Twitter stock in 2022. In February 2024, Judge Laurel Beeler ruled that Musk must testify again. In January 2025, the SEC filed a lawsuit against Musk for securities violations related to his purchase of Twitter. In January 2024, Delaware judge Kathaleen McCormick ruled in a 2018 lawsuit that Musk's $55 billion pay package from Tesla be rescinded. McCormick called the compensation granted by the company's board "an unfathomable sum" that was unfair to shareholders. The Delaware Supreme Court overturned McCormick's decision in December 2025, restoring Musk's compensation package and awarding $1 in nominal damages. Personal life Musk became a U.S. citizen in 2002. From the early 2000s until late 2020, Musk resided in California, where both Tesla and SpaceX were founded. He then relocated to Cameron County, Texas, saying that California had become "complacent" about its economic success. While hosting Saturday Night Live in 2021, Musk stated that he has Asperger syndrome (an outdated term for autism spectrum disorder). When asked about his experience growing up with Asperger's syndrome in a TED2022 conference in Vancouver, Musk stated that "the social cues were not intuitive ... I would just tend to take things very literally ... but then that turned out to be wrong — [people were not] simply saying exactly what they mean, there's all sorts of other things that are meant, and [it] took me a while to figure that out." Musk suffers from back pain and has undergone several spine-related surgeries, including a disc replacement. In 2000, he contracted a severe case of malaria while on vacation in South Africa. Musk has stated he uses doctor-prescribed ketamine for occasional depression and that he doses "a small amount once every other week or something like that"; since January 2024, some media outlets have reported that he takes ketamine, marijuana, LSD, ecstasy, mushrooms, cocaine and other drugs. Musk at first refused to comment on his alleged drug use, before responding that he had not tested positive for drugs, and that if drugs somehow improved his productivity, "I would definitely take them!". The New York Times' investigations revealed Musk's overuse of ketamine and numerous other drugs, as well as strained family relationships and concerns from close associates who have become troubled by his public behavior as he became more involved in political activities and government work. According to The Washington Post, President Trump described Musk as "a big-time drug addict". Through his own label Emo G Records, Musk released a rap track, "RIP Harambe", on SoundCloud in March 2019. The following year, he released an EDM track, "Don't Doubt Ur Vibe", featuring his own lyrics and vocals. Musk plays video games, which he stated has a "'restoring effect' that helps his 'mental calibration'". Some games he plays include Quake, Diablo IV, Elden Ring, and Polytopia. Musk once claimed to be one of the world's top video game players but has since admitted to "account boosting", or cheating by hiring outside services to achieve top player rankings. Musk has justified the boosting by claiming that all top accounts do it so he has to as well to remain competitive. In 2024 and 2025, Musk criticized the video game Assassin's Creed Shadows and its creator Ubisoft for "woke" content. Musk posted to X that "DEI kills art" and specified the inclusion of the historical figure Yasuke in the Assassin's Creed game as offensive; he also called the game "terrible". Ubisoft responded by saying that Musk's comments were "just feeding hatred" and that they were focused on producing a game not pushing politics. Musk has fathered at least 14 children, one of whom died as an infant. The Wall Street Journal reported in 2025 that sources close to Musk suggest that the "true number of Musk's children is much higher than publicly known". He had six children with his first wife, Canadian author Justine Wilson, whom he met while attending Queen's University in Ontario, Canada; they married in 2000. In 2002, their first child Nevada Musk died of sudden infant death syndrome at the age of 10 weeks. After his death, the couple used in vitro fertilization (IVF) to continue their family; they had twins in 2004, followed by triplets in 2006. The couple divorced in 2008 and have shared custody of their children. The elder twin he had with Wilson came out as a trans woman and, in 2022, officially changed her name to Vivian Jenna Wilson, adopting her mother's surname because she no longer wished to be associated with Musk. Musk began dating English actress Talulah Riley in 2008. They married two years later at Dornoch Cathedral in Scotland. In 2012, the couple divorced, then remarried the following year. After briefly filing for divorce in 2014, Musk finalized a second divorce from Riley in 2016. Musk then dated the American actress Amber Heard for several months in 2017; he had reportedly been "pursuing" her since 2012. In 2018, Musk and Canadian musician Grimes confirmed they were dating. Grimes and Musk have three children, born in 2020, 2021, and 2022.[g] Musk and Grimes originally gave their eldest child the name "X Æ A-12", which would have violated California regulations as it contained characters that are not in the modern English alphabet; the names registered on the birth certificate are "X" as a first name, "Æ A-Xii" as a middle name, and "Musk" as a last name. They received criticism for choosing a name perceived to be impractical and difficult to pronounce; Musk has said the intended pronunciation is "X Ash A Twelve". Their second child was born via surrogacy. Despite the pregnancy, Musk confirmed reports that the couple were "semi-separated" in September 2021; in an interview with Time in December 2021, he said he was single. In October 2023, Grimes sued Musk over parental rights and custody of X Æ A-Xii. Elon Musk has taken X Æ A-Xii to multiple official events in Washington, D.C. during Trump's second term in office. Also in July 2022, The Wall Street Journal reported that Musk allegedly had an affair with Nicole Shanahan, the wife of Google co-founder Sergey Brin, in 2021, leading to their divorce the following year. Musk denied the report. Musk also had a relationship with Australian actress Natasha Bassett, who has been described as "an occasional girlfriend". In October 2024, The New York Times reported Musk bought a Texas compound for his children and their mothers, though Musk denied having done so. Musk also has four children with Shivon Zilis, director of operations and special projects at Neuralink: twins born via IVF in 2021, a child born in 2024 via surrogacy and a child born in 2025.[h] On February 14, 2025, Ashley St. Clair, an influencer and author, posted on X claiming to have given birth to Musk's son Romulus five months earlier, which media outlets reported as Musk's supposed thirteenth child.[i] On February 22, 2025, it was reported that St Clair had filed for sole custody of her five-month-old son and for Musk to be recognised as the child's father. On March 31, 2025, Musk wrote that, while he was unsure if he was the father of St. Clair's child, he had paid St. Clair $2.5 million and would continue paying her $500,000 per year.[j] Later reporting from the Wall Street Journal indicated that $1 million of these payments to St. Clair were structured as a loan. In 2014, Musk and Ghislaine Maxwell appeared together in a photograph taken at an Academy Awards after-party, which Musk later described as a "photobomb". The January 2026 Epstein files contain emails between Musk and Epstein from 2012 to 2013, after Epstein's first conviction. Emails released on January 30, 2026, indicated that Epstein invited Musk to visit his private island on multiple occasions. The correspondence showed that while Epstein repeatedly encouraged Musk to attend, Musk did not visit the island. In one instance, Musk discussed the possibility of attending a party with his then-wife Talulah Riley and asked which day would be the "wildest party"; according to the emails, the visit did not take place after Epstein later cancelled the plans.[k] On Christmas day in 2012, Musk emailed Epstein asking "Do you have any parties planned? I’ve been working to the edge of sanity this year and so, once my kids head home after Christmas, I really want to hit the party scene in St Barts or elsewhere and let loose. The invitation is much appreciated, but a peaceful island experience is the opposite of what I’m looking for". Epstein replied that the "ratio on my island" might make Musk's wife uncomfortable to which Musk responded, "Ratio is not a problem for Talulah". On September 11, 2013, Epstein sent an email asking Musk if he had any plans for coming to New York for the opening of the United Nations General Assembly where many "interesting people" would be coming to his house to which Musk responded that "Flying to NY to see UN diplomats do nothing would be an unwise use of time". Epstein responded by stating "Do you think i am retarded. Just kidding, there is no one over 25 and all very cute." Musk has denied any close relationship with Epstein and described him as a "creep" who attempted to ingratiate himself with influential people. When Musk was asked in 2019 if he introduced Epstein to Mark Zuckerberg, Musk responded: "I don’t recall introducing Epstein to anyone, as I don’t know the guy well enough to do so." The released emails nonetheless showed cordial exchanges on a range of topics, including Musk's inquiry about parties on the island. The correspondence also indicated that Musk suggested hosting Epstein at SpaceX, while Epstein separately discussed plans to tour SpaceX and bring "the girls", though there is no evidence that such a visit occurred. Musk has described the release of the files a "distraction", later accusing the second Trump administration of suppressing them to protect powerful individuals, including Trump himself.[l] Wealth Elon Musk is the wealthiest person in the world, with an estimated net worth of US$690 billion as of January 2026, according to the Bloomberg Billionaires Index, and $852 billion according to Forbes, primarily from his ownership stakes in SpaceX and Tesla. Having been first listed on the Forbes Billionaires List in 2012, around 75% of Musk's wealth was derived from Tesla stock in November 2020, although he describes himself as "cash poor". According to Forbes, he became the first person in the world to achieve a net worth of $300 billion in 2021; $400 billion in December 2024; $500 billion in October 2025; $600 billion in mid-December 2025; $700 billion later that month; and $800 billion in February 2026. In November 2025, a Tesla pay package worth potentially $1 trillion for Musk was approved, which he is to receive over 10 years if he meets specific goals. Public image Although his ventures have been highly influential within their separate industries starting in the 2000s, Musk only became a public figure in the early 2010s. He has been described as an eccentric who makes spontaneous and impactful decisions, while also often making controversial statements, contrary to other billionaires who prefer reclusiveness to protect their businesses. Musk's actions and his expressed views have made him a polarizing figure. Biographer Ashlee Vance described people's opinions of Musk as polarized due to his "part philosopher, part troll" persona on Twitter. He has drawn denouncement for using his platform to mock the self-selection of personal pronouns, while also receiving praise for bringing international attention to matters like British survivors of grooming gangs. Musk has been described as an American oligarch due to his extensive influence over public discourse, social media, industry, politics, and government policy. After Trump's re-election, Musk's influence and actions during the transition period and the second presidency of Donald Trump led some to call him "President Musk", the "actual president-elect", "shadow president" or "co-president". Awards for his contributions to the development of the Falcon rockets include the American Institute of Aeronautics and Astronautics George Low Transportation Award in 2008, the Fédération Aéronautique Internationale Gold Space Medal in 2010, and the Royal Aeronautical Society Gold Medal in 2012. In 2015, he received an honorary doctorate in engineering and technology from Yale University and an Institute of Electrical and Electronics Engineers Honorary Membership. Musk was elected a Fellow of the Royal Society (FRS) in 2018.[m] In 2022, Musk was elected to the National Academy of Engineering. Time has listed Musk as one of the most influential people in the world in 2010, 2013, 2018, and 2021. Musk was selected as Time's "Person of the Year" for 2021. Then Time editor-in-chief Edward Felsenthal wrote that, "Person of the Year is a marker of influence, and few individuals have had more influence than Musk on life on Earth, and potentially life off Earth too." Notes References Works cited Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Stonehenge] | [TOKENS: 13213] |
Contents Stonehenge Stonehenge is a prehistoric megalithic structure on Salisbury Plain in Wiltshire, England, two miles (3 km) west of Amesbury. It consists of an outer ring of vertical sarsen standing stones, each around 13 feet (4.0 m) high, seven feet (2.1 m) wide, and weighing around 25 tons, topped by connecting horizontal lintel stones which are held in place with mortise and tenon joints—a feature unique among contemporary monuments. Inside is a ring of smaller bluestones. Inside, these are free-standing trilithons, two bulkier vertical sarsens joined by a single lintel. The whole monument, now in ruins, is aligned towards the sunrise on the summer solstice and sunset on the winter solstice. The stones are set within earthworks in the middle of the densest complex of Neolithic and Bronze Age monuments in England, including several hundred tumuli (burial mounds). Stonehenge was constructed in several phases beginning about 3100 BC and continuing until about 1600 BC. The famous circle of large sarsen stones was placed between 2600 BC and 2400 BC. The surrounding circular earth bank and ditch, which constitute the earliest phase of the monument, have been dated to about 3100 BC. Radiocarbon dating suggests that the bluestones were given their current positions between 2400 and 2200 BC, although they may have been at the site as early as 3000 BC. One of the most famous landmarks in the United Kingdom, Stonehenge is regarded as a British cultural icon. It has been a legally protected scheduled monument since the Ancient Monuments Protection Act 1882 was passed. The site and its surroundings were added to UNESCO's list of World Heritage Sites in 1986. Stonehenge is owned by the Crown Estate and managed by English Heritage; the surrounding land is owned by the National Trust. Stonehenge could have been a burial ground from its earliest beginnings. Deposits containing human bone date from as early as 3000 BC, when the ditch and bank were first dug, and continued for at least another 500 years. Etymology The Oxford English Dictionary cites Ælfric's 10th-century glossary, in which henge-cliff is given the meaning 'precipice', or stone; thus, the stanenges or Stanheng "not far from Salisbury" recorded by 11th-century writers are "stones supported in the air". In 1740, William Stukeley notes: "Pendulous rocks are now called henges in Yorkshire ... I doubt not, Stonehenge in Saxon signifies the hanging stones." Christopher Chippindale's Stonehenge Complete gives the derivation of the name Stonehenge as coming from the Old English words stān 'stone', and either hencg 'hinge' (because the stone lintels hinge on the upright stones) or hen(c)en 'to hang' or 'gallows' or 'instrument of torture' (though elsewhere in his book, Chippindale cites the 'suspended stones' etymology). The "henge" portion has given its name to a class of monuments known as henges. Archaeologists define henges as earthworks consisting of a circular banked enclosure with an internal ditch. As often happens in archaeological terminology, this is a holdover from antiquarian use. Early history Mike Parker Pearson, leader of the Stonehenge Riverside Project based around Durrington Walls, noted that Stonehenge appears to have been associated with burial from the earliest period of its existence: Stonehenge was a place of burial from its beginning to its zenith in the mid third [sic] millennium B.C. The cremation burial dating to Stonehenge's sarsen stones phase is likely just one of many from this later period of the monument's use and demonstrates that it was still very much a domain of the dead. Stonehenge evolved in several construction phases spanning at least 1500 years. There is evidence of large-scale construction on and around the monument, perhaps extending the landscape's time frame to 6500 years. Dating and understanding the various phases of activity are complicated by disturbance of the natural chalk by periglacial effects and animal burrowing, poor quality early excavation records, and a lack of accurate, scientifically verified dates. The modern phasing most generally agreed to by archaeologists is detailed below. Features mentioned in the text are numbered and shown on the plan, right. Archaeologists have found four, or possibly five, large Mesolithic postholes (one may have been a natural tree throw), which date to around 8000 BC, beneath the site of the tourist car park that was in use until 2013. These held pine posts around two feet six inches (0.75 m) in diameter, which were erected and eventually rotted in place. Three of the posts (and possibly four) were aligned east–west, which may have had ritual significance. Another Mesolithic astronomical site in Britain is Warren Field in Aberdeenshire, which is considered the world's oldest lunisolar calendar, corrected yearly by observing the midwinter solstice. Similar but later sites have been found in Scandinavia. A settlement that may have been contemporaneous with the posts has been found at Blick Mead, a reliable year-round spring one mile (1.6 km) from Stonehenge. Salisbury Plain was still wooded, but 4,000 years later, during the earlier Neolithic, people built a causewayed enclosure at Robin Hood's Ball and long barrow tombs in the surrounding landscape. In approximately 3500 BC, a Stonehenge Cursus was built 2,300 feet (700 m) north of the site as the first farmers began clearing the trees and developing the area. Other previously overlooked stone or wooden structures and burial mounds may date as far back as 4000 BC; charcoal from the Blick Mead camp has been dated to that time. The University of Buckingham's Humanities Research Institute believes that the community who built Stonehenge lived there for several millennia, making it potentially "one of the pivotal places in the history of the Stonehenge landscape." The first monument consisted of a circular bank and ditch enclosure made of Late Cretaceous (Santonian Age) Seaford chalk, measuring about 360 feet (110 m) in diameter, with a large entrance to the north east and a smaller one to the south. It stood in open grassland on a slightly sloping spot. The builders placed the bones of deer and oxen in the bottom of the ditch, as well as some worked flint tools. The bones were considerably older than the antler picks used to dig the ditch, and the people who buried them had looked after them for some time prior to burial. The ditch was continuous but had been dug in sections, like the ditches of the earlier causewayed enclosures in the area. The chalk dug from the ditch was piled up to form the bank. This first stage is dated to around 3100 BC, after which the ditch began to silt up naturally. Within the outer edge of the enclosed area is a circle of 56 pits, each about 3.3 feet (1 m) in diameter, known as the Aubrey holes after John Aubrey, the 17th-century antiquarian who was thought to have first identified them. These pits and the bank and ditch together are known as the Palisade or Gate Ditch. The pits may have contained standing timbers creating a timber circle, although there is no excavated evidence of them. A recent excavation has suggested that the Aubrey Holes may have originally been used to erect a bluestone circle. If this were the case, it would advance the earliest known stone structure at the monument by some 500 years. In 2013, a team of archaeologists, led by Parker Pearson, excavated more than 50,000 cremated bone fragments, from 63 individuals, buried at Stonehenge. These remains were originally buried individually in the Aubrey holes, but were exhumed in 1920 during an excavation by William Hawley, who considered them unimportant and in 1935 re-buried them together in one hole, Aubrey Hole 7. Physical and chemical analysis of the remains has shown that the cremated were almost equally men and women, and included some children. There is evidence that the underlying chalk beneath the graves was crushed by substantial weight, so the team concluded that the first bluestones brought from Wales were probably used as grave markers. Radiocarbon dating of the remains has put the date of the site 500 years earlier than previously estimated, to around 3000 BC. A 2018 study of the strontium content of the bones found that many of the individuals buried there around the time of construction had probably come from near the source of the bluestone in Wales and had not extensively lived in the area of Stonehenge before death. Between 2017 and 2021, studies by Parker Pearson and his team suggested that the bluestones used in Stonehenge had been moved there following dismantling of a stone circle of identical size to the first known Stonehenge circle (110 m (360 ft)) at the Welsh site of Waun Mawn in the Preseli Hills. It had contained bluestones, one of which showed evidence of having been reused in Stonehenge. The stone was identified by its unusual pentagonal shape and by luminescence soil dating from the filled-in sockets which showed the circle had been erected around 3400–3200 BC, and dismantled around 300–400 years later, consistent with the dates attributed to the creation of Stonehenge. The cessation of human activity in that area at the same time suggested migration as a reason, but it is believed that other stones may have come from other sources. The second phase of construction occurred approximately between 2900 and 2600 BC. The number of postholes dating to the early third millennium BC suggests that some form of timber structure was built within the enclosure during this period. Further standing timbers were placed at the northeast entrance, and a parallel alignment of posts ran inwards from the southern entrance. The postholes are smaller than the Aubrey Holes, being only around 16 inches (0.4 m) in diameter, and are much less regularly spaced. The bank was purposely reduced in height, and the ditch continued to silt up. At least twenty-five of the Aubrey Holes are known to have contained later, intrusive, cremation burials dating to the two centuries after the monument's inception. It seems that whatever the holes' original function was, it became a funerary one during Phase two. Thirty further cremations were placed in the enclosure's ditch and at other points within the monument, mostly in the eastern half. Stonehenge is therefore interpreted as functioning as an enclosed cremation cemetery at this time, the earliest known cremation cemetery in the British Isles. Fragments of unburnt human bone have also been found in the ditch-fill. Dating evidence is provided by the late Neolithic grooved ware pottery found in association with the features of this phase. Archaeological excavation has indicated that around 2600 BC, the builders abandoned timber in favour of stone and dug two concentric arrays of holes (the Q and R Holes) in the centre of the site. These stone sockets are only partly known (hence, on present evidence, are sometimes described as forming 'crescents'); however, they could be the remains of a double ring. Again, there is little firm dating evidence for this phase. The holes held up to 80 standing stones (shown blue on the plan), only 43 of which can be traced today. It is generally accepted that the bluestones (some of which are made of dolerite, an igneous rock), were transported by the builders from the Preseli Hills, 150 miles (240 km) away in modern-day Pembrokeshire in Wales. Another theory is that they were brought much nearer to the site as glacial erratics by the Irish Sea Glacier although there is no evidence of glacial deposition within southern central England. A 2019 publication announced that evidence of Megalithic quarrying had been found at quarries in Wales identified as a source of Stonehenge's bluestone, indicating that the bluestone was quarried by human agency and not transported by glacial action. The long-distance human transport theory was bolstered in 2011 by the discovery of a megalithic bluestone quarry at Craig Rhos-y-felin, near Crymych in Pembrokeshire, which is the most likely source of some of the stones. Other standing stones may well have been small sarsens (sandstone), used later as lintels. The stones, which weighed about two tons, could have been moved by lifting and carrying them on rows of poles and rectangular frameworks of poles, as recorded in China, Japan, and India. It is not known whether the stones were taken directly from their quarries to Salisbury Plain or were the result of the removal of a venerated stone circle from Preseli to Salisbury Plain to "merge two sacred centres into one, to unify two politically separate regions, or to legitimise the ancestral identity of migrants moving from one region to another". Evidence of a 110-metre (360 ft) stone circle at Waun Mawn near Preseli, which could have contained some or all of the stones in Stonehenge, has been found, including a hole from a rock that matches the unusual cross-section of a Stonehenge bluestone "like a key in a lock". Each monolith measures around 6.6 feet (2 m) in height, between 3.3 and 4.9 ft (1 and 1.5 m) wide and around 2.6 feet (0.8 m) thick. What was to become known as the Altar Stone was believed to have been derived from the Senni Beds, perhaps from 50 miles (80 kilometres) east of the Preseli Hills in the Brecon Beacons. Work announced in 2024 by a team from Curtin University, who analysed the chemical composition of fragments of rock that had fallen off the Altar Stone, and dated them, found that the best match was with rocks in the Orcadian Basin (which includes Caithness, Orkney, and the Moray Firth regions of north-eastern Scotland). The researchers stated that this implies the stone was transported some 430 miles (690 km), and thus demonstrates cultural links between Southern England and Northern Scotland. The north-eastern entrance was widened at this time, so that it precisely matched the direction of the midsummer sunrise and midwinter sunset for the period. This phase of the monument was abandoned unfinished; however, the small standing stones were apparently removed, and the Q and R holes were purposefully backfilled. The Heel Stone, a Tertiary sandstone, may also have been erected outside the north-eastern entrance during this period. It cannot be accurately dated and may have been installed at any time during phase 3. At first, it was accompanied by a second stone, which is no longer visible. Two, or possibly three, large portal stones were set up just inside the north-eastern entrance, of which only one, the fallen Slaughter Stone, 16 feet (4.9 m) long, now remains. Other features, loosely dated to phase 3, include the four Station Stones, two of which stood atop mounds. The mounds are known as "barrows" although they do not contain burials. Stonehenge Avenue, a parallel pair of ditches and banks leading two miles (3 km) to the River Avon, was also added. During the next major phase of activity, 30 enormous Oligocene–Miocene sarsen stones (shown grey on the plan) were brought to the site. They came from a quarry around 16 miles (26 km) north of Stonehenge, in West Woods, Wiltshire. The stones were dressed and fashioned with mortise and tenon joints before 30 sarsens were erected in a circle of standing stones approximately 98 feet (30 m) in diameter, with a ring of 30 lintel stones resting on top. The lintels were fitted to one another using tongue and groove joints – a woodworking method, again. Each standing stone was around 13.5 feet (4.11 m) high, 7.0 feet (2.13 m) wide, and 3.5 feet (1.06 m) deep, weighing around 26 tons. Each had clearly been worked with the final visual effect in mind: The orthostats widen slightly towards the top to keep their perspective constant when viewed from the ground, while the lintel stones curve slightly to continue the circular appearance of the earlier monument. The inward-facing surfaces of the stones are smoother and more finely worked than the outer surfaces. The average thickness of the stones is 3.6 feet (1.1 m) and the average distance between them is 3.3 feet (1 m). A total of 75 stones would have been needed to complete the circle (60 stones) and the trilithon horseshoe (15 stones). It was thought the ring might have been left incomplete, but an exceptionally dry summer in 2013 revealed patches of parched grass which may correspond to the location of missing sarsens. The lintel stones are each around 10 feet (3.2 m) long, 3.3 feet (1 m) wide and 2.6 feet (0.8 m) thick. The tops of the lintels are 16 feet (4.9 m) above the ground. Within this circle stood five trilithons of dressed sarsen stone arranged in a horseshoe shape 45 feet (13.7 m) across, with its open end facing northeast. These huge stones, ten uprights and five lintels, weigh up to 50 tons each. They were linked using complex jointing. They are arranged symmetrically. The smallest pair of trilithons were around 20 feet (6 m) tall, the next pair a little higher, and the largest, single trilithon in the south-west corner would have been 24 feet (7.3 m) tall. Only one upright from the Great Trilithon still stands, of which 22 feet (6.7 m) is visible, and a further 7.9 feet (2.4 m) is below ground. The images of a 'dagger' and 14 'axeheads' have been carved on stone 53, one of the sarsens; further axehead carvings have been seen on the outer faces of stones 3, 4, and 5. The carvings are difficult to date but are morphologically similar to late Bronze Age weapons. Early 21st-century laser scanning of the carvings supports this interpretation. The pair of trilithons in the north-east is the smallest, measuring around 20 feet (6 m) in height; the largest, which is in the south-west of the horseshoe, is almost 25 feet (7.5 m) tall.[dubious – discuss] This ambitious phase has been radiocarbon dated to between 2600 and 2400 BC, slightly earlier than the Stonehenge Archer, discovered in the outer ditch of the monument in 1978, and the two sets of burials, known as the Amesbury Archer and the Boscombe Bowmen, discovered three miles (5 km) to the west. Analysis of animal teeth found two miles (3 km) away at Durrington Walls, thought by Parker Pearson to be the 'builders camp', suggests that, during some period between 2600 and 2400 BC, as many as 4,000 people gathered at the site for the mid-winter and mid-summer festivals; the evidence showed that the animals had been slaughtered around nine months or 15 months after their spring birth. Strontium isotope analysis of the animal teeth showed that some had been brought from as far afield as the Scottish Highlands for the celebrations. At about the same time, a large timber circle and a second avenue were constructed at Durrington Walls overlooking the River Avon. The timber circle was oriented towards the rising Sun on the midwinter solstice, opposing the solar alignments at Stonehenge. The avenue was aligned with the setting Sun on the summer solstice and led from the river to the timber circle. Evidence of huge fires on the banks of the Avon between the two avenues also suggests that both circles were linked. They were perhaps used as a procession route on the longest and shortest days of the year. Parker Pearson speculates that the wooden circle at Durrington Walls was the centre of a 'land of the living', whilst the stone circle represented a 'land of the dead', with the Avon serving as a journey between the two. Later in the Bronze Age, although the exact details of activities during this period are still unclear, the bluestones appear to have been re-erected. They were placed within the outer sarsen circle and may have been trimmed in some way. Like the sarsens, a few have timber-working-style cuts, suggesting that during this phase they may have been linked to lintels and part of a larger structure.[citation needed] This phase saw further rearrangement of the bluestones. They were arranged in a circle between the two rings of sarsens and in an oval at the centre of the inner ring. Some archaeologists argue that some of these bluestones were from a second group brought from Wales. All the stones formed well-spaced uprights without any of the linking lintels inferred in Stonehenge 3 III. The Altar Stone may have been moved within the oval at this time and re-erected vertically. Although this would seem the most impressive phase of work, Stonehenge 3 IV was rather shabbily built compared to its immediate predecessors, as the newly reinstalled bluestones were not well-founded and began to fall over. However, only minor changes were made after this phase.[citation needed] Soon afterwards, the northeastern section of the Phase 3 IV bluestone circle was removed, creating a horseshoe-shaped setting (the Bluestone Horseshoe) which mirrored the shape of the central sarsen Trilithons. This phase is contemporary with the Seahenge site in Norfolk.[citation needed] The Y and Z Holes are the last known construction at Stonehenge, built about 1600 BC, and the last usage of them was probably during the Iron Age. Roman coins and medieval artefacts have been found in or around the monument, but it is unknown whether it was in continuous use throughout British prehistory and beyond, or exactly how it would have been used. Notable is the massive Iron Age hillfort known as Vespasian's Camp (despite its name, not a Roman site), built alongside the Avenue near the Avon. A decapitated seventh-century Saxon man was excavated from Stonehenge in 1923. The site was known to scholars during the Middle Ages and since then it has been studied and adopted by numerous groups. Function and construction Stonehenge was produced by a culture that left no written records. Many aspects of Stonehenge, such as how it was built and for what purposes it was used, remain subject to debate. A number of myths surround the stones. The site, specifically the great trilithon, the encompassing horseshoe arrangement of the five central trilithons, the heel stone, and the embanked avenue, are aligned to the sunset of the winter solstice and the opposing sunrise of the summer solstice. A natural landform at the monument's location followed this line, and may have inspired its construction. It has been conjectured that the design of the monument included a celestial observatory function, which might allow prediction of eclipse, solstice, equinox and other celestial events important to the builders' belief system. The excavated remains of culled animal bones suggest that people may have gathered at the site for the winter rather than the summer. There is little or no direct evidence revealing the construction techniques used by the Stonehenge builders. Over the years, various authors have suggested that supernatural or anachronistic methods were used, often asserting that the stones could not have been moved otherwise due to their massive size. However, conventional techniques, using Neolithic technology as basic as shear legs, have been demonstrably effective at moving and placing stones of a similar size. The most common theory of how prehistoric people moved megaliths has them creating a track of logs along which the large stones were rolled. Another megalith transport theory involves the use of a type of sleigh running on a track greased with animal fat. An experiment with a sleigh carrying a 40-ton slab of stone was successfully conducted near Stonehenge in 1995; a team of more than 100 workers managed to push and pull the slab along the 18-mile (29 km) journey from the Marlborough Downs. Proposed functions for the site include usage as an astronomical observatory or as a religious site. In the 1960s, Gerald Hawkins described in detail how the site was apparently set out to observe the Sun and Moon over a recurring 56-year cycle. More recently, two major new theories have been proposed. Geoffrey Wainwright, president of the Society of Antiquaries of London, and Timothy Darvill, of Bournemouth University, have suggested that Stonehenge was a place of healing—the primeval equivalent of Lourdes. They argue that this accounts for the high number of burials in the area and for the evidence of trauma deformity in some of the graves. However, they do concede that the site was probably multifunctional and used for ancestor worship as well. Isotope analysis indicates that some of the buried individuals were from other regions. A teenage boy buried approximately 1550 BC was raised near the Mediterranean Sea; a metal worker from 2300 BC dubbed the "Amesbury Archer" grew up near the Alpine foothills of Germany; and the "Boscombe Bowmen" probably arrived from Wales or Brittany, France. On the other hand, Mike Parker Pearson of Sheffield University has suggested that Stonehenge was part of a ritual landscape and was joined to Durrington Walls by their corresponding avenues and the River Avon. He suggests that the area around Durrington Walls henge was a place of the living, whilst Stonehenge was a domain of the dead. A journey along the Avon to reach Stonehenge was part of a ritual passage from life to death, to celebrate past ancestors and the recently deceased. Both explanations were first mooted in the twelfth century by Geoffrey of Monmouth, who extolled the curative properties of the stones and was also the first to advance the idea that Stonehenge was constructed as a funerary monument. There are other hypotheses and theories. According to a team of British researchers led by Mike Parker Pearson of the University of Sheffield, Stonehenge may have been built as a symbol of "peace and unity", indicated in part by the fact that at the time of its construction, Britain's Neolithic people were experiencing a period of cultural unification. Stonehenge megaliths include smaller bluestones and larger sarsens (a term for silicified sandstone boulders found in the chalk downs of southern England). The bluestones are composed of dolerite, tuff, rhyolite, or sandstone. The igneous bluestones appear to have originated in the Preseli hills of southwestern Wales, about 140 miles (230 km) from the monument. The sandstone Altar Stone may have originated in east Wales. Analysis published in 2020 indicates the sarsens came from West Woods, about 16 miles (26 km) from the monument. Researchers from the Royal College of Art in London have discovered that the monument's igneous bluestones possess "unusual acoustic properties": when struck, they produce a "loud clanging noise". Rocks with such acoustic properties are frequent in the Carn Melyn ridge of Presili; the Presili village of Maenclochog (Welsh for bell or ringing stones) used local bluestones as church bells until the 18th century. According to the team, these acoustic properties could explain why certain bluestones were hauled such a long distance, a major technical accomplishment at the time. In certain ancient cultures, rocks that ring out, known as lithophonic rocks, were believed to possess mystical or healing powers, and Stonehenge has a history of association with rituals. The presence of these "ringing rocks" seems to support the hypothesis that Stonehenge was a "place for healing" put forward by Darvill, who consulted with the researchers. Stonehenge-builders and DNA studies There is evidence to suggest that despite the introduction of farming in the British Isles, the practice of cereal cultivation fell out of favour between 3300 and 1500 BC, with much of the population following a pastoralist subsistence pattern focused on hazelnut gathering and pig and cattle rearing. A majority of Stonehenge's major phases of construction occurred during this period, during which evidence of large-scale agriculture is equivocal. Similar associations between non-cereal farming subsistence patterns and monumental construction are seen at Poverty Point and Sannai Maruyama. Researchers studying DNA extracted from Neolithic human remains across Britain determined that the people who built Stonehenge I and II were closely related to Iberian and Central European Early and Middle Neolithic populations, modelled as having about 75% ancestry from Early European Farmers who came from the Eastern Mediterranean, travelling west from there, and 25% ancestry coming from Western Hunter-Gatherers from western Europe. These farmers moved to Iberia before heading north, reaching Britain in about 4,000 BC. Most of the ancestry of British Neolithic farmers came from the people who followed this route, with a minor contribution from groups who followed the Danube into Central and Western Europe. Their agricultural techniques seem to have come originally from Anatolia, and their mixture appears to have happened primarily on the continent before the Neolithic farmers migrated to Britain. At the time of their arrival, Britain was inhabited by hunter-gatherer groups, the first inhabitants of the island after the last Ice Age ended about 11,700 years ago. The farmers replaced most of the hunter-gatherer population in the British Isles without mixing much with them.[b] Despite their mostly Aegean ancestry, the paternal (Y-DNA) lineages of Neolithic farmers in Britain were almost exclusively of Western Hunter-Gatherer origin.[c] This was also the case among other megalithic-building populations in northwest Europe,[d][e] meaning that these populations were descended from a mixture of hunter-gatherer males and farmer females.[f] The dominance of Western Hunter-Gatherer male lineages in Britain and northwest Europe is also reflected in a general 'resurgence' of hunter-gatherer ancestry, predominantly from males, across western and central Europe in the Middle Neolithic.[g] At the time the megalithic Stonehenge 3 II was constructed (2600–2400 BC) by Neolithic people, the Bell Beaker people arrived, around 2,500 BC, migrating from mainland Europe. They lived side by side for ca. 500 years, with the Bell Beaker people probably incorporating the henge-structures into their belief-system. The earliest British individuals associated with the Beaker culture, most likely speakers of Indo-European languages whose ancestors migrated from the Pontic–Caspian steppe, were similar to those from the Rhine. Eventually, there was again a large population replacement in Britain. More than 90% of Britain's Neolithic gene pool was replaced with the arrival of the Bell Beaker people, who had approximately 50% Western Steppe Herders ancestry. Roman era In 1979, Richard J. C. Atkinson applied newly developed stratigraphical techniques to dispose of the theory that the Roman army had attempted to demolish the monument as a centre for druidic resistance: the stone fragments he previously thought were incorporated into the fourth- or fifth-century AD stratigraphy he now assigned to the original builders dressing the stones, or to quarrying of material in the Middle Bronze Age. An excavation in 2008, together with an analysis of earlier excavations, suggested that during the Roman era the monument was the site of substantial activity, beyond mere casual occupation. Coins from the late fourth century, a large quantity of Roman-era pottery, and pit-buried bones of food animals indicated that the location had importance as a ritual or ceremonial site. The end of a square-cut trench, incorporating a bluestone slab and containing a Roman coin, was interpreted as a grave. Medieval period A decapitated skeleton of a male, aged 28–32, was excavated by William Hawley in 1926. It was found within the stone circles, close to Y-Hole 9 on the central axis. Radiocarbon analysis allocates a date of between 600–690 AD to the find. The grave was shallow, and it had been necessary to cram the body into the space, breaking most of the ribs. The head was placed on top. Archaeologist Mike Pitts interprets this sacrificial or judicial execution as evidence that Stonehenge retained significance in the Middle Ages. He identifies the post holes found near the grave as suggestive of a gallows, thus affording a link with the contemporary name of henge—hanging. Aubrey Burl, however, contends that the name refers to the shape of the trilithons, which resemble a gibbet for multiple hangings. Modern history Throughout recorded history, Stonehenge and its surrounding monuments have attracted attention from antiquarians and archaeologists. Architect Inigo Jones considered Stonehenge to have been built in Roman times. John Aubrey was one of the first to examine the site with a scientific eye in 1666. In his plan of the monument, he recorded the pits that now bear his name, the Aubrey holes. William Stukeley continued Aubrey's work in the early eighteenth century but also considered the surrounding monuments, identifying (somewhat incorrectly) the Cursus and the Avenue. He also began excavating many of the barrows in the area. His interpretation of the landscape linked it to the Druids. Stukeley was so fascinated with Druids that he originally named Disc Barrows Druids' Barrows. The most accurate early plan of Stonehenge was that made by Bath architect John Wood, the Elder, in 1740. His original annotated survey has now been computer-redrawn and published.: 195 Importantly, Wood's plan was made before the collapse of the southwest trilithon, which fell in 1797 and was restored in 1958. William Cunnington was the next to formally assess the area in the early nineteenth century. He excavated some 24 barrows before digging in and around the stones, discovering charred wood, animal bones, pottery, and urns. He also identified the hole in which the Slaughter Stone once stood. Richard Colt Hoare supported Cunnington's work and excavated some 379 barrows on Salisbury Plain, including some 200 in the area around the Stones, some excavated in conjunction with William Coxe. To alert future diggers to their work, they were careful to leave initialled metal tokens in each barrow they opened. Cunnington's finds are displayed at the Wiltshire Museum. In 1877, Charles Darwin dabbled in archaeology at the stones, experimenting with the rate at which remains sink into the earth, for his book The Formation of Vegetable Mould Through the Action of Worms. Stone 22 fell during a fierce storm on 31 December 1900. William Gowland oversaw the first major restoration of the monument in 1901. That involved straightening and concrete-setting of sarsen stone number 56, which was in danger of falling. In straightening the stone, he moved it about half a metre from its original position. Gowland also took the opportunity to further excavate the monument in what was the most scientific dig to date, revealing more about the erection of the stones than the previous 100 years of work had done. During the 1920 restoration, William Hawley, who had excavated nearby Old Sarum, excavated the base of six stones and the outer ditch. He also located a bottle of port wine in the Slaughter Stone socket left by Cunnington, helped to rediscover Aubrey's pits inside the bank, and located the concentric circular holes outside the Sarsen Circle called the Y and Z Holes. Richard J. C. Atkinson, Stuart Piggott and J. F. S. Stone re-excavated much of Hawley's work in the 1940s and 1950s, and discovered the carved axes and daggers on the sarsen stones. Atkinson's work was instrumental in advancing understanding of the monument's three major phases of construction. In 1958, the stones were restored again, when three of the standing sarsens were re-erected and set in concrete bases. The last restoration was carried out in 1963 after stone 23 of the Sarsen Circle fell over. It was again re-erected, and the opportunity was taken to concrete three more stones. Later archaeologists, including Christopher Chippindale of the Museum of Archaeology and Anthropology, University of Cambridge, and Brian Edwards of the University of the West of England, campaigned to give the public more knowledge of the various restorations and, in 2004, English Heritage included pictures of the work in progress in its book Stonehenge: A History in Photographs. In 1966 and 1967, prior to the construction of a new car park at the site, the area of land immediately northwest of the stones was excavated by Faith and Lance Vatcher. They discovered the Mesolithic postholes dating from between 7000 and 8000 BC, as well as a 10-metre (33 ft) length of a palisade ditch —a V-cut ditch into which timber posts had been inserted that remained there until they rotted away. Subsequent aerial archaeology suggests that this ditch runs from the west to the north of Stonehenge, near the avenue. Excavations were once again carried out in 1978 by Atkinson and John Evans, during which they discovered the remains of the Stonehenge Archer in the outer ditch. In 1979, rescue archaeology was needed alongside the Heel Stone after a cable-laying ditch was mistakenly dug on the roadside, revealing a new stone hole next to the Heel Stone. In the early 1980s, Julian C. Richards led the Stonehenge Environs Project, a detailed study of the surrounding landscape. The project successfully dated features such as the Lesser Cursus, Coneybury Henge, and several other smaller features. In 1993, the way that Stonehenge was presented to the public was called 'a national disgrace' by the House of Commons Public Accounts Committee. Part of English Heritage's response to this criticism was to commission research to collate and summarize all the archaeological work conducted at the monument to date. This two-year research project culminated in the publication in 1995 of the monograph Stonehenge in its landscape, the first to present the complex stratigraphy and the finds recovered from the site. It presented a rephasing of the monument. More recent excavations include a series of digs conducted between 2003 and 2008 known as the Stonehenge Riverside Project, led by Mike Parker Pearson. The project mainly investigated other monuments in the landscape and their relationship to the stones—notably, Durrington Walls, where another "Avenue" leading to the River Avon was discovered. The point where Stonehenge Avenue meets the river was also excavated, revealing a previously unknown circular area that likely housed four additional stones, most likely serving as a marker for the avenue's starting point. In April 2008, Tim Darvill of the University of Bournemouth and Geoff Wainwright of the Society of Antiquaries began another dig inside the stone circle to retrieve datable fragments of the original bluestone pillars. They were able to date the erection of some bluestones to 2300 BC, although this may not reflect the earliest erection of stones at Stonehenge. They also discovered organic material dating to 7000 BC, which, along with the Mesolithic postholes, supports the site having been in use at least 4,000 years before Stonehenge was started. In August and September 2008, as part of the Riverside Project, Julian C. Richards and Mike Pitts excavated Aubrey Hole 7, removing the cremated remains from several Aubrey Holes that had been excavated by Hawley in the 1920s, and re-interred in 1935. A licence for the removal of human remains at Stonehenge had been granted by the Ministry of Justice in May 2008, in accordance with the Statement on burial law and archaeology issued in May 2008. One of the conditions of the licence was that the remains should be reinterred within two years and that, in the intervening period, they should be kept safely, privately, and decently. A new landscape investigation was conducted in April 2009. A shallow mound, rising to about 16 in (40 centimetres), was identified between stones 54 (inner circle) and 10 (outer circle), clearly separated from the natural slope. It has not been dated, but speculation that it represents careless backfilling following earlier excavations seems disproved by its representation in eighteenth- and nineteenth-century illustrations. There is some evidence that, as an uncommon geological feature, it could have been deliberately incorporated into the monument at the outset. A circular, shallow bank, little more than four inches (10 cm) high, was found between the Y and Z hole circles, with a further bank lying inside the "Z" circle. These are interpreted as the spread of spoil from the original Y and Z holes, or, more speculatively, as hedge banks planted deliberately to screen activities within. In 2010, the Stonehenge Hidden Landscape Project discovered a "henge-like" monument less than 0.62 mi (1 km) away from the main site. This new hengiform monument was subsequently revealed to be located "at the site of Amesbury 50", a round barrow in the Cursus Barrows group. In November 2011, archaeologists from the University of Birmingham announced the discovery of evidence of two huge pits positioned within the Stonehenge Cursus pathway, aligned in celestial position towards midsummer sunrise and sunset when viewed from the Heel Stone. The discovery was made as part of the Stonehenge Hidden Landscape Project which began in the summer of 2010. The project uses a non-invasive geophysical imaging technique to reveal and visually recreate the landscape. According to team leader Vince Gaffney, this discovery may provide a direct link between the rituals and astronomical events to activities within the Cursus at Stonehenge. In December 2011, geologists from the University of Leicester and the National Museum of Wales announced the discovery of the source of some of the rhyolite fragments found in the Stonehenge debitage. These fragments do not seem to match any of the standing stones or bluestone stumps. The researchers have identified the source as a 230-foot (70 m) long rock outcrop called Craig Rhos-y-felin (51°59′30″N 4°44′41″W / 51.99167°N 4.74472°W / 51.99167; -4.74472 (Craig Rhos-y-Felin)), near Pont Saeson in north Pembrokeshire, located 140 miles (220 km) from Stonehenge. In 2014, the University of Birmingham announced findings including evidence of adjacent stone and wooden structures and burial mounds near Durrington, Wiltshire, overlooked previously, that may date as far back as 4000 BC. An area extending to 4.6 square miles (12 km2) was studied to a depth of three metres with ground-penetrating radar equipment. As many as 17 new monuments revealed nearby may be Late Neolithic monuments resembling Stonehenge. The interpretation suggests a complex of numerous related monuments. Also included in the discovery is that the cursus track is terminated by two 16-foot (5 m) wide, extremely deep pits, whose purpose is still a mystery. In July 2020, a study led by David Nash of the University of Brighton concluded that the large sarsen stones were "a direct chemical match" to those found at West Woods near Marlborough, Wiltshire, some 15 miles (25 km) north of Stonehenge. A core sample, originally extracted in 1958, had recently been returned. First, the fifty-two sarsens were analysed using methods including x-ray fluorescence spectrometry to determine their chemical composition, which revealed they were mostly similar. The core was then destructively analysed and compared with stone samples from various locations in southern Britain. Fifty of the fifty-two megaliths were found to match sarsens in West Woods, thereby identifying the probable origin of the stones. During 2017 and 2018, excavations by professor Parker Pearson's team at Waun Mawn, a large stone circle site in the Preseli Hills, suggested that the site had originally housed a 110-metre (360 ft) diameter stone circle of the same size as Stonehenge's original bluestone circle, also orientated towards the midsummer solstice. The circle at Waun Mawn also contained a hole from one stone which had a distinctive pentagonal shape, very closely matching the one pentagonal stone at Stonehenge (stonehole 91 at Waun Mawn and stone 62 at Stonehenge). Soil dating of the sediments within the revealed stone holes, via optically stimulated luminescence (OSL), suggested the absent stones at Waun Mawn had been erected around 3400–3200 BC, and removed around 300–400 years later, a date consistent with theories that the same stones were moved and used at Stonehenge, before later being reorganised into their present locations and supplemented with local sarsens as was already understood. Human activity at Waun Mawn ceased around the same time which has suggested that some people may have migrated to Stonehenge. It has also been suggested that stones from other sources may have been added to Stonehenge, perhaps from other dismantled circles in the region. Further work in 2021 by Parker Pearson's team concluded that the Waun Mawn circle had never been completed, and of the stones which might once have stood at the site, no more than 13 had been removed in antiquity.[h] In February 2021, archaeologists announced the discovery of "vast troves of Neolithic and Bronze Age artifacts" while conducting excavations for the proposed highway tunnel near Stonehenge. The find included Bronze Age graves, late Neolithic pottery, and a C-shaped enclosure on the intended site of the Stonehenge road tunnel. The remains also contained a shale object in one of the graves, burnt flint in a C-shaped enclosure, and the final resting place of a baby. In January 2022, archaeologists announced the discovery of thousands of prehistoric pits during an electromagnetic induction field survey around Stonehenge. Based on the shapes of the pits and the artifacts found inside, the study's lead author, Philippe De Smedt, concluded that prehistoric humans excavated six of the nine large pits. One of the oldest was about 10000 years old and contained hunting tools. In August 2024, the journal Nature published research from a team at Curtin University in Australia identifying the origin of the Altar Stone, which is partially buried by a collapsed sarsen stone, as having come from the Orcadian Basin in northeast Scotland, some 700 km away. The Heel Stone lies northeast of the sarsen circle, beside the end portion of Stonehenge Avenue. It is roughly textured, 16 feet (4.9 m) above ground, and leans in towards the stone circle. It has been known by many names in the past, including "Friar's Heel" and "Sun-stone". At the Summer solstice an observer standing within the stone circle, looking northeast through the entrance, would see the Sun rise in the approximate direction of the Heel Stone, and the Sun has often been photographed over it. A folk tale relates the origin of the Friar's Heel reference. The Devil bought the stones from a woman in Ireland, wrapped them up, and brought them to Salisbury plain. One of the stones fell into the Avon, the rest were carried to the plain. The Devil then cried out, "No-one will ever find out how these stones came here!" A friar replied, "That's what you think!", whereupon the Devil threw one of the stones at him and struck him on the heel. The stone stuck in the ground and is still there. Brewer's Dictionary of Phrase and Fable attributes this tale to Geoffrey of Monmouth. Though book eight of Geoffrey's Historia Regum Britanniae describes how Stonehenge was built, the two stories are entirely different. The name is not unique; a monolith with the same name was recorded in the nineteenth century by the antiquarian Charles Warne at Long Bredy in Dorset. The twelfth-century Historia Regum Britanniae ("History of the Kings of Britain"), by Geoffrey of Monmouth, includes a legend of Stonehenge's origin, describing how Stonehenge was brought from Ireland with the help of the wizard Merlin. Geoffrey's story spread widely, with variations of it appearing in adaptations of his work, such as Wace's Norman French Roman de Brut, Layamon's Middle English Brut, and the Welsh Brut y Brenhinedd. According to the tale, the stones of Stonehenge were healing stones, which giants had brought from Africa to Ireland. They had been raised on Mount Killaraus to form a stone circle, known as the Giant's Ring or Giant's Round. The fifth-century king Aurelius Ambrosius wished to build a great memorial to the British Celtic nobles slain by the Saxons at Salisbury. Merlin advised him to use the Giant's Ring. The king sent Merlin and Uther Pendragon (King Arthur's father) with 15,000 men to bring it from Ireland. They defeated an Irish army led by Gillomanius, but were unable to move the huge stones. With Merlin's help, they transported the stones to Britain and re-erected them as they had stood. Mount Killaraus may refer to the Hill of Uisneach. Although the tale is fiction, archaeologist Mike Parker Pearson suggests it may hold a "grain of truth" as the Stonehenge bluestones were likely brought from the Waun Mawn stone circle on the Irish Sea coast of Wales. Another legend tells how the invading Saxon king Hengist invited British Celtic warriors to a feast but treacherously ordered his men to massacre the guests, killing 420 of them. Hengist erected Stonehenge on the site to show his remorse. Stonehenge has changed ownership several times since King Henry VIII acquired Amesbury Abbey and its surrounding lands. In 1540, Henry gave the estate to the Earl of Hertford. It subsequently passed to Lord Carleton and then the Marquess of Queensberry. The Antrobus family of Cheshire bought the estate in 1824. Stonehenge was one of several lots put up for auction in 1915 by Sir Cosmo Gordon Antrobus, after he inherited the estate from his brother. The auction by Knight Frank & Rutley estate agents in Salisbury was held on 21 September 1915 and included "Lot 15. Stonehenge with about 30 acres, 2 rods, 37 perches [12.44 ha] of adjoining downland." Cecil Chubb bought the site for £6,600 (£668,000 in 2023) and gave it to the nation three years later, with certain conditions attached. Although it has been speculated that he purchased it at the suggestion of – or even as a present for – his wife, in fact, he bought it on a whim, believing a local man should be the new owner. The plot bought by Chubb and gifted to the nation was only 30 acres (12 ha) in size, and various buildings stood within clear sight of the monument, the most prominent being Stonehenge Aerodrome. Some 300 metres (980 ft) from the stones, the aerodrome was built during the First World War for the Royal Flying Corps and its large stone and brick hangars dominated the skyline. In the dry valley at Stonehenge Bottom, a main road junction was built between what would later be designated as the A303 and A344 roads, along with several cottages and a cafe. In 1927, the land around Stonehenge was put up for auction in three plots. Plot A lay immediately west of the monument and included the (by now disused) Stonehenge Aerodrome, Plot B was to the south on the other side of the main road, and Plot C on the north side included part of the Stonehenge Cursus. There was developer interest, and in August 1927, a subscription fund was launched to "save the skyline" of the monument. The subscription made rapid progress, with George V as the lead subscriber, and by October 1927 £8,000 had been raised, which was enough to purchase Plot A and start the demolition of the aerodrome. The fund continued for a number of years to secure the remaining land around the henge for the nation, with fundraising for Plot C continuing through 1929. The land was taken into the management of the National Trust to preserve. The last large aircraft hangar was removed in 1930, and by the middle of the 1930s, the aerodrome site was cleared. More recently, the land has been part of a grassland reversion scheme, returning the surrounding fields to native chalk grassland. This process continued in 2022 when the National Heritage Lottery Fund (NHLF) gave a grant to the National Trust to acquire another 170 hectares of the Stonehenge Landscape. During the twentieth century, Stonehenge began to revive as a place of religious significance, this time by adherents of Neopaganism and New Age beliefs, particularly the Neo-druids. The historian Ronald Hutton would later remark that "it was a great, and potentially uncomfortable, irony that modern Druids had arrived at Stonehenge just as archaeologists were evicting the ancient Druids from it." The first such Neo-druidic group to make use of the megalithic monument was the Ancient Order of Druids, who performed a mass initiation ceremony there in August 1905, in which they admitted 259 new members into their organisation. This assembly was largely ridiculed in the press, which mocked the fact that the Neo-druids were dressed up in costumes consisting of white robes and fake beards. The earlier rituals were complemented by the Stonehenge Free Festival, loosely organised by the Polytantric Circle, held between 1972 and 1984, during which time the number of midsummer visitors had risen to around 30,000. However, in 1985, the site was closed to festivalgoers by a High Court injunction. A consequence of the end of the festival in 1985 was the violent confrontation between the police and New Age travellers that became known as the Battle of the Beanfield, when police blockaded a convoy of travellers to prevent them from approaching Stonehenge. Beginning in 1985, the year of the confrontation, no access to the stones at Stonehenge was allowed for any religious purpose. This "exclusion-zone" policy continued for almost fifteen years: until just before the arrival of the twenty-first century, visitors were not allowed to go into the stones at times of religious significance, the winter and summer solstices, and the vernal and autumnal equinoxes. Following a European Court of Human Rights ruling obtained by campaigners such as Arthur Uther Pendragon, the restrictions were lifted. The ruling recognized that members of any genuine religion have a right to worship in their own church, and Stonehenge is a place of worship to Neo-Druids, Pagans and other "Earth based' or 'old' religions. Meetings were organised by the National Trust and others to discuss the arrangements. In 1998, a party of 100 people was allowed access, and these included astronomers, archaeologists, Druids, locals, pagans, and travellers. In 2000, an open summer solstice event was held, and about seven thousand people attended. In 2001, the numbers increased to about 10,000. When Stonehenge was first opened to the public, it was possible to walk among and even climb on the stones, but they were roped off in 1977 due to serious erosion. Visitors are no longer permitted to touch the stones but are able to walk around the monument from a short distance away. English Heritage does, however, permit access during the summer and winter solstice, and the spring and autumn equinox. Additionally, visitors can make special bookings to access the stones throughout the year. Approximately 30,000 local residents are entitled to free admission to Stonehenge under an agreement made in 1921. As motorised traffic increased, the setting of the monument began to be affected by the proximity of the two roads – on the north side the A344 to Shrewton and Devizes which passed within three metres of the Heel Stone, and to the south the A303, a trunk route connecting London with Devon and Cornwall. In 1979, the Department of the Environment proposed moving visitor facilities into the dip of Stonehenge Bottom. In 1985, a commission set up by English Heritage recommended closing the A344 and building a visitor centre on Army land north of the monument to replace the "woefully inadequate" facilities and cater for an expected 1 million visitors per year. The access situation and the proximity of the two roads continued to draw criticism, highlighted by a 2006 National Geographic survey. In the survey of conditions at 94 leading World Heritage Sites, 400 conservation and tourism experts ranked Stonehenge 75th in the list of destinations, declaring it to be "in moderate trouble". The controversy surrounding re-routing of the roads led to the scheme being cancelled on multiple occasions. In December 2007, the government announced that plans to build a Stonehenge road tunnel under the landscape and create a permanent visitors' centre had been cancelled on cost grounds. In 2009, the government gave approval for a £25 million scheme to create a smaller visitors' centre and close the A344, although this was dependent on funding and local authority planning consent. In 2010, Wiltshire Council granted planning permission for a centre 1.5 mi (2.4 kilometres) to the west, and English Heritage confirmed that funds to build it would be available, supported by a £10m grant from the Heritage Lottery Fund. In June 2013, the A344 was closed to begin the work of removing the section of road and replacing it with grass. The centre, designed by Denton Corker Marshall, opened to the public in December 2013. An announcement in November 2020 stated that a plan to construct a four-lane tunnel to take traffic below the site had been approved. This was intended to eliminate the section of the A303 that runs close to the circle. The plan had received opposition from a group of "archaeologists, environmentalists and modern-day druids" according to National Geographic but was supported by others who wanted to "restore the landscape to its original setting and improve the experience for visitors". Opponents of the plan were concerned that artifacts underground in the area would be lost, or that excavation in the area could destabilize the stones, leading to their sinking, shifting, or even falling. In July 2023, the Department for Transport announced that, despite the original planning application having been overturned by the High Court in 2021, the Transport Secretary, Mark Harper, had approved plans for a 2-mile (3.2 km) road tunnel. In February 2024, the High Court in London rejected a fresh bid by campaigners to stop construction of the road tunnel. A further legal challenge was made in the High Court in July 2024. Although the High Court dismissed this action in October 2024, the incoming Labour government had already announced in July that the tunnel would 'not move forward'. In March 2025, English Heritage announced that planning permission had been granted for two buildings to be constructed near the visitor facilities: a 'Learning Centre' to the east of the shuttle bus turning circle and a 'Neolithic classroom' near the existing recreated Neolithic village. These are due to open in the autumn of 2026. The site has been subject to intermittent vandalism for centuries. Until the 17th century, stones disappeared from the site to be employed at building sites. In the 19th century, tourists employed chisels to cut rock chips off the megaliths as souvenirs. Although the first years of the Free Festival (annual, from 1975 onwards) saw "very little vandalism", Stonehenge was fenced off from 1978 onwards. Later, repeated vandalism in the 1980s and 1990s led the authorities to deploy up to hundreds of police, erect barriers around Stonehenge, and impose exclusion zones up to six kilometres from the archaeological monument. The vandalism of 1984 included defacing the monument with purple spray paint. The government went so far as to close Stonehenge to protect it from vandalism, but in the face of public outcry, the government opted to reopen it. In 2008, two men used a hammer and a screwdriver to take a small chip the size of a 10p coin from the side of the Heel Stone, in what authorities described as "the first vandalism in decades". In 2020, the British transport minister was accused of vandalism when he decided that the road through the Stonehenge area would be converted into a tunnel that would pass in the immediate vicinity. The project was decades old, but had repeatedly been delayed because of its cost or the effects on archaeological remains. The historian Tom Holland opined that "To inflict this act of vandalism on this landscape seems unbelievable." Tunnel opponents considered it "state-sponsored vandalism" even as their case was defeated in court in 2024. In July 2024, the recently elected Labour government cancelled the tunnel plan. See also Historical context Other monuments in the Stonehenge ritual landscape About Stonehenge and replicas of Stonehenge Fiction Similar sites Sites with similar sunrise or sunset alignments Museums with collections from the World Heritage Site Footnotes References Sources External links |
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Contents Alibaba Group Alibaba Group Holding Limited, branded as Alibaba (/ˌæliˈbɑːbə, ˌɑː-/), is a Chinese multinational technology company specializing in e-commerce, retail, Internet, and technology. Founded on 28 June 1999 in Hangzhou, Zhejiang, the company provides consumer-to-consumer (C2C), business-to-consumer (B2C), and business-to-business (B2B) sales services via Chinese and global marketplaces, as well as local consumer, digital media and entertainment, logistics, and cloud computing services. It owns and operates a diverse portfolio of companies around the world in numerous business sectors. On 19 September 2014, Alibaba's American initial public offering (IPO) on the New York Stock Exchange raised US$25 billion, giving the company a market value of US$231 billion and, by far, then the largest IPO in world history. It is one of the top 10 most valuable corporations, and is named the 31st-largest public company in the world on the Forbes Global 2000 2020 list. In January 2018, Alibaba became the second Asian company to break the US$500 billion valuation mark, after its competitor Tencent. As of 2022[update], Alibaba has the ninth-highest global brand valuation. Alibaba is one of the world's largest retailers and e-commerce companies. In 2020, it was also rated as the fifth-largest artificial intelligence company. The company hosts the largest B2B (Alibaba.com), C2C (Taobao), and B2C (Tmall) marketplaces in the world. It has been expanding into the media industry, with revenues rising by triple percentage points year after year. It also set the record on the 2018 edition of China's Singles' Day, the world's biggest online and offline shopping day. Naming The company's name came from the character Ali Baba from the Middle Eastern folk-tale collection One Thousand and One Nights because of its universal appeal. As Jack Ma, one of the founders, replied to Lorraine Hahn on TalkAsia: One day I was in San Francisco in a coffee shop, and I was thinking Alibaba is a good name. And then a waitress came, and I said do you know about Alibaba? And she said yes. I said what do you know about Alibaba, and she said 'Open Sesame.' And I said yes, this is the name! Then I went onto the street and found 30 people and asked them, 'Do you know Alibaba'? People from India, people from Germany, people from Tokyo and China. ... They all knew about Alibaba. Alibaba—open sesame. Alibaba—40 thieves. Alibaba is not a thief. Alibaba is a kind, smart business person, and he helped the village. So ... easy to spell, and global know [sic]. Alibaba opens sesame for small- to medium-sized companies. We also registered the name AliMama, in case someone wants to marry us! History On 28 June 1999, Jack Ma, with 17 friends and students founded Alibaba.com, a China-based B2B marketplace site, in his Hangzhou apartment. In October 1999, Alibaba received a US$25 million investment from Swedish Wallenberg family's Investor AB, Goldman Sachs and SoftBank. In 1999, Wallenbergs Investor AB owned 6% of the shares. Alibaba.com was expected to improve the domestic e-commerce market and perfect an e-commerce platform for Chinese enterprises, especially small and medium-sized enterprises (SMEs), to help export Chinese products to the global market as well as to address World Trade Organization (WTO) challenges. In 2002, Alibaba.com became profitable three years after launch. Ma wanted to improve the global e-commerce system, so from 2003 onward, Alibaba launched Taobao Marketplace, Alipay, Alimama.com, and Lynx. When eBay announced its expansion into China in 2003, Ma viewed the American company as a foreign competitor and rejected eBay's buyout of Alibaba's subsidiary Taobao. By applying existing technologies, gaining trust in the Chinese e-commerce market, and expanding through dominating the market at a loss before making a return on additional services, Alibaba's subsidiaries outperformed eBay in the Chinese e-commerce market, claiming a growing percentage of consumers from eBay. Alibaba subsidiary Taobao would later force eBay out of the Chinese market, with eBay closing its unprofitable China Web unit, though the two companies would break even six years later. In 2005, Yahoo! invested in Alibaba through a variable interest entity (VIE) structure, buying a 40% stake in the company for US$1 billion. This would as a result net in US$10 billion in Alibaba's IPO alone to Yahoo!. In 2012, China Investment Corporation led a group of Chinese investors in buying out Yahoo!'s 40% stake and in buying the Alibaba shares that had traded on the Hong Kong Stock Exchange.: 130 According to Li Chuan, a senior executive at Alibaba, the company was planning in 2013 to open traditional brick and mortar retail outlets in partnership with Wanda Group, a Chinese real estate company. Additionally, Alibaba purchased a 25% stake in Hong Kong-listed Chinese department store chain Intime Retail in early 2014. In early 2017, Alibaba and Intime's founder Shen Guojun agreed to pay as much as HK$19.8 billion (US$2.6 billion) to take the store chain private. Alibaba's stake—28% from 2014's US$692 million investment—would rise to about 74% after the deal. In April 2014, Alibaba invested in Lyft, along with Coatue Management, and Andreessen Horowitz; they led a US$250 million Series D financing round. On 5 June 2014, Alibaba bought a 50% stake of Guangzhou Evergrande F.C. from Evergrande Real Estate Group Ltd. in a deal that was worth 1.2 billion yuan (US$192 million). On 5 September 2014, the group—in a regulatory filing with the US Securities and Exchange Commission (SEC)—set a US$60- to $66- per-share price range for its scheduled initial public offering (IPO), the final price of which would be determined after an international roadshow to gauge the investor interest in Alibaba shares to shareholders. On 18 September 2014, Alibaba's IPO priced at US$68, raising US$21.8 billion for the company and investors. Alibaba was the biggest US IPO in history, bigger than Google, Facebook, and Twitter combined. On 19 September 2014, Alibaba's shares (BABA) began trading on the NYSE at an opening price of $92.70 at 11:55 am EST. On 22 September 2014, Alibaba's underwriters announced their confirmation that they had exercised a greenshoe option to sell 15% more shares than originally planned, boosting the total amount of the IPO to $25 billion. Beginning in mid-2015, Alibaba invested in Paytm, an India-based mobile payment platform.: 9 Alibaba and the underwriters of its IPO were sued in a California superior court in a consolidated class action lawsuit. The lawsuit was filed in October 2015 on behalf of investors who purchased Alibaba's American depositary shares alleging violations of the Securities Act. Alibaba reached a settlement agreement in December 2018, subject to court approval, in which it agreed to pay $75 million to settle the lawsuit. Alibaba is among the most prominent investors in Thailand's Eastern Economic Corridor, which was opened in 2018.: 57 Alibaba committed approximately US$320 million for the development of an e-commerce digital hub in the EEC.: 57 In January 2017, Alibaba and the International Olympic Committee jointly announced an $800 million deal that would last until 2028 where the company would sponsor the Olympic Games. In September 2018, Jack Ma, the main founder of Alibaba, announced that he would step down as chairman in a year's time so he could focus on philanthropy. In response to the announcement, The Economist stated that Ma had a significant impact in China and worldwide via contributions and dedication to various businesses. In May 2019, Bloomberg cited sources familiar with the matter as saying that Alibaba was considering raising $20 billion through a second listing in Hong Kong. In November 2019, Alibaba raised 12.9 billion in its secondary listing in Hong Kong, which became the world's largest offering that year. On Tuesday, 10 September 2019, Jack Ma officially stepped down as the chairman of Alibaba, Daniel Zhang succeeded him at the head of the company. In November 2020, The Wall Street Journal reported that Chinese leader Xi Jinping personally scuttled Jack Ma's Ant Group IPO. Bo Zhuang, chief China economist at TS Lombard said that the suspension "forms part of a wider political drive as the leadership seeks to widen and consolidate its control over finance and technology". What followed was an unexpected Chinese government-released draft on 10 November 2020, which gives regulatory authorities a wider latitude to regulate their biggest tech enterprises. In December 2020, the shares of Alibaba Group suffered a historic stock price crash to the lowest close in around 6 months, following the antitrust investigation into the company by Chinese regulators. In December 2020, China's State Administration for Market Regulation (SAMR) stated that it opened an investigation into Alibaba over monopolistic practices. The country's central bank, as well as three other regulators, confirmed in a separate statement that the affiliated Ant Group would also be summoned for discussions over "competition and consumer rights", where regulators instructed the company to return its focus to digital-payments. People's Daily, the official newspaper of the Central Committee of the Chinese Communist Party, endorsed the investigation shortly after the announcement, claiming the investigation to be "an important step in strengthening antimonopoly oversight in the internet sphere". As a result, from the antitrust probe, Alibaba lost nearly all of its stock-market gains in 2020, from $859 billion to $586 billion, by the end of December. Jack Ma, co-founder of both Alibaba and Ant Group, vanished from public view when Ant's IPO was suspended in early November, but resurfaced in January 2021 in a 50-second video, appearing briefly via video link at the digitally facilitated Rural Teacher Initiative. As of February 2021, he has yet to be seen in public. The video appearance caused Alibaba stock to jump more than 7%. Jack Ma made a public appearance in Hangzhou, China in March 2023 where he met with students and teachers at the Alibaba partners-funded Yungu School. In February 2021, Alibaba sold $5 billion in bonds, the company's third large sale of dollar bonds, issuing four sets priced to yield between 2.143% and 3.251%. The four sets of bonds were $1.5 billion of both 10-year and 30-year debt along with $1 billion of bonds due in 20 and 40 years. The 20-year bonds were designated as sustainability notes. On 9 April 2021, as part of a Chinese crackdown on big tech, SAMR issued a $2.8 billion fine against Alibaba for anti-competitive practices and ordered Alibaba to file self-examination and compliance reports to the SAMR for three years. This amounted to 12% Archived 3 June 2021 at the Wayback Machine of its 2020 net profit. Critics say the move tightens the Chinese's governments control of tech companies. Alibaba stated that it would dedicate itself to correct its errors and accepted the fine without making any appeal.: 57 On 11 November 2021, it was reported that over the course of its 11-day Singles' Day sales extravaganza, Chinese e-commerce giant Alibaba Group Holding received a record 540.3 billion yuan (S$114.4 billion) in orders, a 14 percent increase over the previous year. In July 2022, the SEC added Alibaba to a list of companies facing delisting from U.S. stock exchanges if its auditors remain unable to examine Alibaba's books before 2024. In December 2022, a state-owned enterprise of the China Internet Investment Fund, established by the Cyberspace Administration of China, took a 1 percent golden share investment in two Alibaba subsidiaries that control Youku and UCWeb. In March 2023, Alibaba announced their "1+6+N" restructuring plan, which reorganized its business structure into six independently run entities: Cloud Intelligence Group, Taobao and Tmall Group, Cainiao Smart Logistics Network, Local Services group, Alibaba International Digital Commerce, and the Digital Media and Entertainment group. Each business unit would have their own CEO and board of directors and be able to seek their own fundraising and market listings. Under the new "1+6+N" structure, Alibaba also established a Capital Management Committee and a Compliance and Risk Committee. The Wall Street Journal reported on 30 March that Jack Ma engineered this in talks with company CEO Daniel Zhang while he was overseas. In September 2023, Cainiao Smart Logistics Network Ltd., the logistics arm of Alibaba Group, has filed for its Hong Kong initial public offering, potentially making it among the first of the Chinese e-commerce leader's units to go public. In December 2024, Alibaba announced it would sell Intime Department Store to Youngor Group. In November 2025, the Financial Times published a report stating that a U.S. national security memo accused Alibaba of providing capabilities to the People's Liberation Army used to target the U.S. Alibaba disputed the report. In January 2026, Texas governor Greg Abbott prohibited Alibaba products and services on all government devices and networks. Corporate affairs The key trends for Alibaba are (as at the financial year ending 31 March): Alibaba is viewed by the Chinese government as one of its national champion corporations.: 156 Alibaba supplies a significant amount of technology for the Digital Silk Road.: 272 Companies and affiliated entities Buyers who visit Alibaba.com are looking to purchase wholesale from thousands of product categories. Alibaba.com later became the world's largest online B2B trading platform for small businesses as of 2014. Alibaba.com has three main services: the English language portal Alibaba.com, which handles sales between importers and exporters from more than 240 countries and regions, the Chinese portal 1688.com, which manages domestic B2B trade in China, and AliExpress.com, a global consumer marketplace. Alibaba.com went public at the Hong Kong Stock Exchange in 2007, and was delisted again in 2012. Two years later in 2014, Alibaba.com was privately held again following a $2.5 billion buyback. In 2013, 1688.com launched a direct channel that was responsible for $30 million in daily transaction value. In 2003, Alibaba launched Taobao Marketplace (淘宝网), offering a variety of products for retail sales. Taobao grew to become China's largest C2C online shopping platform and later became the second most visited website in China, according to Alexa Internet. Taobao's growth was attributed to offering free registration and commission-free transactions using a free third-party payment platform. Advertising made up 75 percent of the company's total revenue, allowing it to break even in 2009. In 2010, Taobao's profit was estimated to be ¥1.5 billion (US$235.7 million), which was only about 0.4 percent of their total sales figure of ¥400 billion (US$62.9 billion) that year, way below the industry average of 2 percent, according to iResearch estimates. According to Zhang Yu, the director of Taobao, between 2011 and 2013, the number of stores on Taobao with annual sales under ¥100 thousand increased by 60%; the number of stores with sales between ¥10 thousand and ¥1 million increased by 30%, and the number of stores with sales over ¥1 million increased by 33%. In April 2008, Taobao introduced a spin-off, Taobao Mall (淘宝商城, later Tmall.com), an online retail platform to complement the Taobao C2C portal, offering global brands to an increasingly affluent Chinese consumer base. It became the eighth most visited web site in China as of 2013. In 2012, Tmall.com later changed its Chinese name to Tianmao (天猫, "sky cat"), reflecting Tmall's Chinese pronunciation. In March 2010, Taobao launched the group shopping website Juhuasuan (聚划算), offering "flash sales", which are products that are available at a discount for only a fixed time period. In October 2010, Taobao beta-launched eTao, a comparison shopping website that offers search results from mostly Chinese online shopping platforms, including product searches, sales and coupon searches. According to the Alibaba Group web site, eTao offers products from Amazon China, Dangdang, Gome, Yihaodian, Nike China, and Vancl, as well as Taobao and Tmall. As part of a restructuring of Taobao by Alibaba, these spin-offs became separate companies in 2011, with Tmall and eTao becoming separate businesses in June and Juhuasuan becoming a separate business later in October. In 2010, Alibaba launched AliExpress.com, an online retail service made up of mostly small Chinese businesses offering products to international online buyers. It is the most visited e-commerce platform in Russia. It allows small businesses in China to sell to customers all over the world, resulting in a wide variety of products. It might be more accurate to compare AliExpress to eBay, though, as sellers are independent; it simply serves as a host for other businesses to sell to consumers. Similar to eBay, sellers on Aliexpress can be either companies or individuals. It connects Chinese businesses directly with buyers. The main difference from Taobao is that it's aimed primarily at international buyers, mainly the US, Russia, Brazil and Spain. In 2012, Alibaba instituted its Public Dispute Resolution Center, which crowdsources buyers and sellers to vote on transactional rules and decide the outcome of disputes on the platform.: 215 This decentralized approach was popular and similar mechanisms were adopted or experimented with by other e-commerce platforms in China.: 215–216 On 11 June 2014, Alibaba launched US shopping site 11 Main. The 11 Main marketplace hosts more than 1,000 merchants in categories such as clothing, fashion accessories and jewelry as well as interior goods and arts and crafts and it plans to keep adding more, said the company. On 23 June 2015, Alibaba announced that it is selling 11 Main to OpenSky, an online-marketplace operator based in New York. In February 2015, Alibaba invests US$590 million in Meizu, acquiring an undisclosed minority stake. In June 2015, Alibaba started a joint venture Koubei with its affiliate Ant Financial Group to tap China's fast-growing local services market, each investing approximately US$483 million into the business for an equal equity stake. In 2016, Alibaba acquired control of Singapore-based e-commerce platform Lazada.: 49 Lazada is the largest e-commerce platform in southeast Asia, with a major presence in Malaysia, the Philippines, Singapore, Thailand, and Vietnam.: 49 This acquisition increased integration on Alibaba between Chinese merchants and their customers in southeast Asia.: 50 In October 2016, Alibaba launched Alitrip, later named Fliggy, an online travel platform that is designed as an online mall for brands such as airline companies and agencies. Fliggy set the target audience as the younger generation and it strives to become a one-stop service when they plan their trips, particularly in overseas travel. On 7 August 2017, Alibaba Group and Marriott International hotel group announced a comprehensive strategic co-operation. Two companies will set up a joint venture company. Through the docking technology system and the superiority resources, Fliggy has Marriott hotel flagship store. It has the same function with Marriott Chinese website and Marriott mobile app to create the best global travel experience for consumers. In 2016, the Office of the United States Trade Representative added Taobao back onto a list of notorious counterfeit platforms that includes the likes of torrent site The Pirate Bay. Alibaba denied wrongdoing and filed two lawsuits against the counterfeiters as of 4 January 2017[update], but brands whose sales have been affected by the counterfeit products accused Alibaba of not doing enough. In 2017, Alibaba started opening a chain of supermarkets, named Freshippo (or Hema; 盒马), as part of the company's "new retail strategy," where customers can either order in the store or online for delivery in under 30 minutes. It offers a mobile app that recommends customers products based on data analytics. In addition, customers can have their groceries cooked to eat in the food court of the supermarket. In October 2018, it was reported that Alibaba's Koubei have merged with online food delivery service platform Ele.me into a new local life service subsidiary. However, the newly formed Alibaba Local Life Service entity experienced major competition from local service giant Meituan, which is backed by Tencent, leading to rumours of planned layoffs in 2022. In September 2019, Alibaba announced it would acquire Chinese e-commerce platform Kaola from NetEase for around US$2 billion. In October 2020, Alibaba agreed to pay US$3.6 billion to take control of China's biggest hypermarket operator Sun Art (SEHK: 6808) from French billionaire Mulliez family. The deal doubled the group's stake in the hypermarket chain with a total ownership of 72%. Alibaba.com offers a paid Gold Supplier membership to try to ensure that each seller is genuine; sellers' Gold Supplier status and the number of years it has been held are displayed. The supplier verification types and checks are listed on Alibaba.com's website, with more stringent checks for sellers outside China. While the majority of suppliers are reported to be genuine,[citation needed] there have been many cases of sellers, some with Gold Supplier status, seeking to defraud unsuspecting buyers. In February 2011, controversy ensued when Alibaba's corporate office admitted that it had granted the mark of integrity of its "China Gold Supplier" program to more than 2,000 dealers that had subsequently defrauded buyers; the firm's share price dropped "abruptly" after the announcement. A statement from the firm reported that Yan Limin, the general manager of Alibaba.com at the time, had been dismissed in March for "misconduct"; Phil Muncaster of UK's The Register additionally reported that "a further 28 employees had been involved in dodgy dealings". As The Economist noted, the company's response has conflicting components: Alibaba's promulgated view that its corrective actions indicate its commitment to quality and integrity (where it contrasts itself with other scandal-associated Chinese business sectors), versus a damage control view suggesting that the subscription-driven, third-party verified "China Gold Supplier" program was endangered by diminished trust in its endorsement system, removing the incentive for global buyers to choose Alibaba as their business-to-business service, thus more broadly endangering Alibaba through impact on its brand and capabilities (the latter via the "defenestration of senior people"). The scandal was said to have placed the head of Alibaba Group, Jack Ma—who was described as having been furious over the scandal—in a position to personally fight to win back trust. In 2013, Alibaba and six large Chinese logistics companies (including SF Express) established a company called Cainiao for delivery of packages in China. This network gradually grew to 14 local logistics companies in 2014. In 2016, Alibaba's Taobao and Tmall, two of the world's largest and most popular online retail marketplaces, achieved a total transaction volume of 3 trillion yuan (US$478.6 billion). The company aims to double the transaction volume to 6 trillion yuan by 2020. As of February 2018[update], Taobao reached 580 million monthly active users, while Tmall achieved 500 million monthly active users. It is also rapidly expanding its e-commerce network abroad. Alibaba has also announced that it will invest 100 billion yuan over five years to build a global logistics network, underpinning an aggressive overseas expansion, and demonstrating Alibaba's commitment to building the most efficient logistics network in China and around the world. It is investing a further 5.3 billion yuan in Cainiao Logistics to boost its stake to 51 percent from 47 percent. The investment would value Cainiao, a joint venture of top Chinese logistics firms, at around US$20 billion. Alibaba uses Cainiao software at its Belgian-European sales hub. The software is able to access data about retailers, products, transport details and flows, a person familiar with the company's IT systems told the British newspaper Financial Times. Chinese companies are legally obliged to pass on their data to China's authorities and security services. The Belgium State Security Service is monitoring the hub in Lütich because of this fact and possible espionage. According to the Financial Times, Cainiao denied suggestions of wrongdoing, noting that the firm operates in compliance with relevant laws and regulations. According to the Reuters, Alibaba Group Holding Ltd has divested its logistics arm for $8.5 billion to a consortium led by investment firms Boyu Capital and Primavera Capital Group. In conjunction with the company's 10th anniversary, Alibaba launched Alibaba Cloud in September 2009, aiming to build a cloud computing service platform, including e-commerce data mining, e-commerce data processing, and data customization. It has R&D centres and operators in Hangzhou, Beijing, Hong Kong, Singapore, Silicon Valley and Dubai. In July 2014, Alibaba Cloud entered into a partnership deal with Inspur. Alibaba Cloud is the largest high-end cloud computing company in China. In 2009, Alibaba acquired HiChina, the largest domain registration service and web hosting service company in China, and built it into Alibaba Cloud. On 28 July 2011, Alibaba Cloud released AliOS (formerly Yun OS and Aliyun OS), a Linux distribution designed for mobile devices. In the 2017 Computing Conference in Hangzhou, Alibaba launched AliGenie, a China-based open-platform intelligent personal assistant. It is currently used in the Tmall Genie smart speaker. In 2018, Alibaba's Wanli Min presented City Brain, a technology geared towards urban solutions such as streamlining traffic, detecting accidents and improving transport efficiency. China's government designated Alibaba as one of its "AI champions" in 2018.: 281 On 27 July 2019, Alibaba unveiled a 64-bit RISC-V processor called the XuanTie-910 (Black Iron 910). It is a 12 nm 16-core with a clockrate of 2.5 GHz, and was designed by Alibaba's subsidiary T-Head (also known as Pingtouge). Alibaba claim the Xuantie-910 is faster than the ARM Cortex-A73 and is capable of 7.1 Coremark/MHz. On 25 September 2019, Alibaba announced an AI accelerator called the Hanguang 800. The Hanguang 800 contains 17 billion transistors built with a 12 nm process and was designed by T-Head and DAMO Academy (Alibaba's research team). Alibaba claim it is capable of 78,563 images per second (IPS) inference and 500 IPS/W in ResNet-50. The Hanguang 800 will be available to be rented on Alibaba Cloud. In April 2023, Alibaba revealed its plans to release Tongyi Qianwen, a ChatGPT-like chatbot. Its name means "seeking an answer by asking a thousand questions". This AI product, which can support both English and Chinese languages, will be incorporated into the company's various business operations. It will initially be integrated into the messaging app, DingTalk, and the voice-activated smart speaker, Tmall Genie. According to Alibaba, drafting emails, creating business proposals, and converting meeting dialogues into written notes are among Tongyi Qianwen's capabilities. Media reported that the company has received more than 200,000 requests from businesses to join its beta testing program, from industries as varied as fintech, electronics, transport, fashion and dairy farming as of April 2023. Alibaba is also integrating Tongyi Qianwen into a digital assistant called Tingwu. Tongyi Tingwu, the AI-powered assistant, can analyze multimedia content and generate a text summary from video and audio files. In November 2024, Alibaba unveiled QwQ-32B-Preview, a groundbreaking 32.5 billion parameter AI reasoning model that challenges OpenAI's o1 series by demonstrating superior performance on AIME and MATH benchmark.[citation needed] This innovative model, developed by Alibaba's Qwen team, can process prompts up to 32,000 words long and features a unique self-fact-checking mechanism that allows it to solve complex logic puzzles and mathematical problems.[citation needed] While impressive, the model is not without limitations, as it may unexpectedly switch languages, get stuck in reasoning loops, and struggle with common sense reasoning.[citation needed] Notably, the model is available under an Apache 2.0 license on Hugging Face, making it commercially accessible, though only certain components have been released.[citation needed] Its development comes amid growing skepticism about traditional AI scaling laws and represents a new approach to AI reasoning that involves giving models more processing time to complete tasks.[citation needed] In April 2025, Alibaba Cloud release Wan 2.1-FLF2V-14B Artificial Intelligence Video Generation Model under Apache license. In December 2020, The New York Times reported that Alibaba had developed and marketed facial recognition and surveillance software configured to detect Uyghur faces and those of other ethnic minorities in China. Alibaba responded that they "do not and will not permit our technology to be used to target or identify specific ethnic groups" and that it was "dismayed to learn" that its Alibaba Cloud subsidiary had developed this feature, defending that the technology was developed "in a testing environment" and that it "was not deployed by any customer." However, IPVM reported in December 2020 that Alibaba refused to provide any proof the Uyghur recognition feature was just a "test" or "trial" and that Alibaba's own website showed Uyghur recognition as a live feature. In September 2017, Alibaba created a new live entertainment business unit under its Digital Media and Entertainment Group which focuses on ticketing, content creation and live experiences, bringing its entertainment ticketing platform Damai and its content creation and technology units MaiLive and Maizuo under one roof. It aims to provide a platform for live events (e.g. concerts, plays, esports and sports events), as well as supporting content partners and leveraging Alibaba's data capability for offline shows. It also provides the online digital distribution service 9Apps, which hosts downloadable content and applications. In March 2014, Alibaba agreed to acquire a controlling stake in ChinaVision Media Group for $804 million. The two firms announced they would establish a strategic committee for potential future opportunities in online entertainment and other media areas. The company was renamed Alibaba Pictures Group (SEHK: 1060). In March 2015, Alibaba Group launched AliMusic as its music division. Xiami Music and Tiantian Music are two of music streaming APP owned by AliMusic. AliMusic named Gao Xiaosong as the chairman and Song Ke as chief executive officer in July 2015. In 2017, Tencent Music has expected $10bn IPO by signing a rights deal with Alibaba, strengthening its position within the important Chinese market. Under the terms of the deal Alibaba will gain the right to stream music from international labels such as Sony Music, Universal Music Group and YG Entertainment, which already have exclusive deals with Tencent, in return for offering to its catalogue from Rock Records, HIM International Music and so on. In April 2014, Alibaba and Yunfeng Capital, a private equity company controlled by Alibaba's founder, Jack Ma, agreed to acquire a combined 18.5 percent stake in Youku Tudou, which broadcasts a series of popular television programs and other videos over the Internet. Alibaba acquired a stake in Youku Tudou for $1.22 billion in 2014. In its 2023 financial report, Alibaba disclosed a $1.2 billion impairment charge related to losses incurred by Youku. Since restructuring in March 2023, the Digital Media and Entertainment Group has been led by Fan Luyuan as CEO. In June 2025, Alibaba Pictures Group officially changed its name to Damai Entertainment Holdings Limited. Its business has expanded from film to a diversified ecosystem including performances, IP commercial derivatives, TV series, artist management, and ticketing platforms. In 2004, the Alibaba Group released Aliwangwang, an instant messaging software service for interactions between customer and online sellers. By 2014, there are 50 million Aliwangwang users, making it the second-largest instant messaging tool in China. In October 2013, the Alibaba's chairman Jack Ma announced that the Alibaba Group would no longer use Tencent's messaging application WeChat, and would henceforth promote its own messaging application and service, Laiwang. In April 2014, Alibaba Group and UCWeb, a Chinese provider of mobile internet software technology and services, launched Shenma (神马), a mobile-only search engine, as part of a joint venture. Later in June, the Alibaba Group acquired UCWeb, with an international product portfolio that includes a mobile browsing service (UC Browser), app and game distribution platforms (9Apps and 9Game), a mobile traffic platform (UC Union) and UC News that primarily caters to all types of news in the India market (as an aggregator) among others. Alibaba's Y Projects Business Unit developed the Xuexi Qiangguo app, which is used to teach Xi Jinping Thought and other aspects of the history and ideology of the Chinese Communist Party. In October 2005, Alibaba Group formed a strategic partnership with Yahoo! and acquired Yahoo! China, a Chinese portal previously launched on 24 September 1999 that focuses on Internet services like news, email, and search. In April 2013, Alibaba Group announced that, as part of the agreement to buy back the Yahoo! Mail stake, that they would suspend technological support for China Yahoo! Mail service and begin migration of Yahoo! China Mail accounts. Several options were offered to users to make the transition as smooth as possible, and Yahoo! China users had four months to migrate their accounts to the Aliyun mail service, the Yahoo! Mail service in the United States, or to another third-party e-mail provider of the user's choice. Yahoo! China closed its mail service on 19 August 2013. E-mails sent to Yahoo! China accounts could be forwarded to an Alimail box until 31 December 2014. Users were also allowed to transfer e-mail accounts to yahoo.com or any other e-mail service. It is estimated there are no more than a million users with Yahoo! Mail for China and chances are they also own other e-mail accounts. In 2014, Alibaba Group founded DingTalk, an enterprise communication and collaboration platform. Also known as Ding Ding, the app was developed as part of efforts to compete with rival Tencent's WeChat. DingTalk is managed by Alibaba's cloud computing division. In 2004, the Alibaba Group launched Alipay, a third-party online payment platform. It also provides an escrow service, in which buyers can verify whether they are happy with goods they have bought before releasing money to the seller. Prior to Alipay, third-party payment was a legal grey area in China.: 32 As Alipay's popularity increased, it became accepted by Chinese regulators.: 32–33 In 2010, the People's Bank of China issued administrative measures regarding non-financial payment services.: 33 These measures retroactively recognized the legal status of online third-party payment platforms like Alipay.: 33 Alibaba Group spun off Alipay in 2010 in a controversial move. In 2011, Alipay obtained a license to become one of the first licensed non-financial institutions to conduct payment operations.: 33 According to analyst research report, Alipay has the biggest market share in China with 300 million users and control of just under half of China's online payment market in February 2014. In 2013, Alipay launched a financial product platform called Yu'ebao (余额宝). Alipay partnered with the Tianhong Asset Management to launch it to the general public. Yu'ebao offers an online money market account in which Alipay customers can deposit money and receive a higher interest rate than that available from banks.: 33 It soon became China's largest online money market fund and prompted competitors like Baidu and Tencent to introduce alternatives.: 33 The People's Bank of China supported the growth of such funds with a permissive regulatory environment initially but began increasing regulation of such funds in 2017.: 33 On 16 October 2014, the Alipay company was re-branded as Ant Financial Services (now Ant Group). One of the factors for Alibaba's success in this platform is the company's quick and reliable payment system, where it offers several types of payment systems such as credit card, debit card, Alipay, Quick-pay, and online banking. These payment systems help to cope with simultaneous cash flow transactions with ease and convenience. Ant Financial was ranked sixth in Fortune's Change the World list, recognized for the positive green environmental impact of its Ant Forest, the world's largest platform for tracking individuals' carbon footprints. Ant Financial and its partners have achieved considerable success in the reduction of CO2 emissions. Ant Financial is the highest valued fintech company in the world, and the world's most valuable unicorn (start-up) company, with a valuation of US$150 billion. In August 2020, Ant Financial, a subsidiary of Alibaba, launched the IPO program, valued at US$200 billion. In 2014, Alibaba and Yunfeng Capital, a private equity firm, launched Alibaba Health when the two companies bought a 54% stake in CITIC 21CN for HK$1.33 billion (US$171 million). It is listed on the Hong Kong Stock Exchange as SEHK: 241. It positions itself as a pharmaceutical e-commerce business and medical services. In the same year, Alibaba acquired Chinese map supplier AutoNavi. In April 2015, the group also reached an agreement to transfer its online B2C pharmacy, Tmall Medical (yao.Tmall.com), to AliHealth. The integration provides consumers a wide range of pharmaceutical and health products available in China. In 2015, Alibaba later launched its Shanghai-based sports division, AliSports, after a consolidation of some of the parent company's existing business units. The new company's operations encompass television and digital sports rights, event operation, venue commercialization, copyright, media, business development, gaming, and ticketing. AliSports secured exclusive title sponsorship of the FIFA Club World Cup from 2015 to 2022. The company announced a Champion of Champions rugby sevens tournament in 2017, to be played in Shanghai for the highest prize money ever offered in the sport. In December 2015, Alibaba agreed to acquire the South China Morning Post and other media assets belonging to the group for a consideration of $266 million. Although Alibaba promised editorial independence, vice-chairman Joseph Tsai said that Alibaba believes that "the world needs a plurality of views when it comes to China coverage. China's rise as an economic power and its importance to world stability is too important for there to be a singular thesis." The acquisition attracted media concerns over what this would mean for the newspaper's coverage. Other subsidiaries of Alibaba include Hangzhou Ali Venture Capital and Alibaba Entrepreneurs Fund. Hangzhou Ali Venture Capital (杭州阿里创业投资) is a company 80% owned by Jack Ma and another manager of Alibaba. For regulatory purpose, Alibaba Group did not own the company directly, but by pleading. It was considered as a subsidiary and/or consolidated entity of Alibaba Group. Ali Venture Capital is a shareholder of Beijing Enlight Media and a domestic shareholder of China Unicom. The Alibaba Entrepreneurs Fund is a non-profit making initiative launched by Alibaba Group in 2015. Alibaba also has invested in more than ten startups in Hong Kong including DayDayCook, GoGoVan, WeLend and Qupital. In 2019, Alibaba launched China-Russia flights in collaboration with Russian Post to assure fast shipping of products. Alibaba owns the app Feizhu, which is a platform on which companies can sell tourism services such as day trips or cultural activities to Chinese consumers.: 121 When Alibaba acquires shares in other businesses, it generally seeks to acquire a controlling stake and maintain control over the business operations.: 92–93 Corporate governance Alibaba's main co-founder Jack Ma served as the executive chairman of the Alibaba Group from its founding until 10 September 2019. Daniel Zhang succeeded Ma and has also served as Alibaba's CEO since 2015. J. Michael Evans has served as Alibaba's president since 2015. Jack Ma had stepped down as CEO in 2013 and chose Jonathan Lu as his successor. The Alibaba Group under Lu was performing well, though there were rumors that Ma was growing distrustful in Lu's ability to lead the company. Daniel Zhang, who served as COO of Alibaba under Lu, succeeded Lu as CEO in 2015. On 10 September 2018, Ma chose Zhang to succeed him as executive chairman of the Alibaba Group after his stepping down announcement, and this would go into effect in 1 year on 10 September 2019. Since 2012, when Xi Jinping succeeded the CCP general secretary, the Chinese Communist Party (CCP) has had a CCP Committee secretary in place in the company and has over 2,000 party members as Alibaba employees. In September 2019, the municipal government of Hangzhou announced that it was assigning government officials to work with tech companies and manufacturers in Zhejiang province, including Alibaba, in what city officials stated was an effort "to facilitate communication and expedite projects". After the Russian invasion of Ukraine, Alibaba faced criticism for continuing to do business in Russia. In August 2023, Ukraine's National Agency on Corruption Prevention designated the company an 'international sponsor of war' owing to it providing a platform for the sale of copper goods sourced from the occupied territories of Ukraine. In 2023, Alibaba Group Holding Ltd has announced Joseph Tsai as the new chairman and Eddie Wu as the CEO. This move comes as the company seeks to revive growth in the post-crackdown era, with Tsai providing strategic direction and Wu driving operational excellence. Around 44% of Alibaba shares are held by the general public and around 40% are held by institutions. Around 14% are held by SoftBank Group. The largest shareholders in early 2024 were: Social responsibility In 2014, the Chinese government and Alibaba partnered to create the rural e-commerce expansion program Rural Taobao, which aimed to provide rural households with the same level of access to consumer goods that urban residents have and to facilitate the sale of agricultural goods through e-commerce.: 129 As of 2017, the program covered 16,500 villages.: 130 Beginning in March 2016, Alibaba and the Communist Youth League began a collaboration to promote online entrepreneurship among rural Chinese youth.: 129 Later that year, Alibaba signed other rural development agreements with the National Development and Reform Commission and Ministry of Agriculture.: 129 In May 2017, Alibaba signed a memorandum with the Supreme People's Procuratorate's Anti-Corruption Bureau "to create a clean, credible, rule-of-law market environment.": 77 Pursuant to the memorandum, the Bureau provides Alibaba and Ant Group with access to criminal records from bribery cases and Alibaba and Ant Group query those records including during verification of Taobao sellers and in connection with anti-money laundering initiatives and financial risk controls.: 77 On 7 August 2021, Alibaba fired a manager who admitted to "indecent acts" with an inebriated employee. The case highlighted issues of sexual harassment in the workplace. Alibaba actively promotes female employment, collaborating with the All-China Women's Federation for community e-commerce events. The company also donates to UN Women to support female employment initiatives. Half of Alibaba's employees are women, with one-third of leadership roles, especially in departments like human resources, held by women. Alibaba collaborates with Hangzhou's smart city initiative and efforts to digitize the economy and build a cashless city.: 122–123 See also References External links 30°11′31″N 120°11′07″E / 30.19194°N 120.18528°E / 30.19194; 120.18528 |
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[SOURCE: https://en.wikipedia.org/wiki/Habitable_planet] | [TOKENS: 10015] |
Contents Planetary habitability Planetary habitability is a measure used in astrobiology to characterize a planet's or a natural satellite's potential to develop and sustain an environment hospitable to life. The Planetary Habitability Laboratory maintains a catalog of potentially habitable exoplanets. Background Research suggests that life on a planetary body may develop through abiogenesis or be transferred from one body to another, through a hypothetical process known as panspermia. Environments do not need to contain life to be considered habitable nor are accepted habitable zones (HZ) the only areas in which life might arise. As the existence of life beyond Earth is not known, planetary habitability is largely an extrapolation of conditions on Earth and the characteristics of the Sun and Solar System which appear favorable to life's flourishing. Of particular interest are those factors that have sustained complex, multicellular organisms on Earth and not just simpler, unicellular creatures. Research and theory in this regard is a component of a number of natural sciences, such as astronomy, planetary science, and the emerging discipline of astrobiology. An absolute requirement for life is an energy source, and the notion of planetary habitability implies that many other geophysical, geochemical, and astrophysical criteria must be met before an astronomical body can support life. In its astrobiology roadmap, NASA has defined the principal habitability criteria as "extended regions of liquid water, conditions favorable for the assembly of complex organic molecules, and energy sources to sustain metabolism". In August 2018, researchers reported that water worlds could support life. Habitability indicators and biosignatures must be interpreted within a planetary and environmental context. In determining the habitability potential of a body, studies focus on its bulk composition, orbital properties, atmosphere, and potential chemical interactions. Stellar characteristics of importance include mass and luminosity, stable variability, and high metallicity. Rocky, wet terrestrial-type planets and moons with the potential for Earth-like chemistry is a primary focus of astrobiological research. However, more speculative habitability theories occasionally examine alternative biochemistries and other types of astronomical bodies. The idea that planets beyond Earth might host life is an ancient one, though historically it was framed by philosophy as much as physical science.[a] The late 20th century saw two breakthroughs in the field. The observation and robotic spacecraft exploration of other planets and moons within the Solar System has provided critical information on defining habitability criteria and allowed for substantial geophysical comparisons between the Earth and other bodies. The discovery of exoplanets, beginning in the early 1990s and accelerating thereafter, has provided further information for the study of possible extraterrestrial life. These findings confirm that the Sun is not unique among stars in hosting planets and expands the habitability research horizon beyond the Solar System. While Earth is the only place in the Universe known to harbor life, estimates of habitable zones around other stars, along with the discovery of thousands of exoplanets and new insights into the extreme habitats on Earth where organisms known as extremophiles live, suggest that there may be many more habitable places in the Universe than considered possible until very recently. On 4 November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way. 11 billion of these estimated planets may be orbiting Sun-like stars. The nearest such planet may be 12 light-years away, according to the scientists. As of June 2021, a total of 59 potentially habitable exoplanets have been found. Stellar characteristics An understanding of planetary habitability begins with the host star. The classical habitable zone (HZ) is defined for surface conditions only; but a metabolism that does not depend on the stellar light can still exist outside the HZ, thriving in the interior of the planet where liquid water is available. Under the auspices of SETI's Project Phoenix, scientists Margaret Turnbull and Jill Tarter developed the "HabCat" (or Catalogue of Habitable Stellar Systems) in 2002. The catalog was formed by winnowing the nearly 120,000 stars of the larger Hipparcos Catalogue into a core group of 17,000 potentially habitable stars, and the selection criteria that were used provide a good starting point for understanding which astrophysical factors are necessary for habitable planets. According to research published in August 2015, very large galaxies may be more favorable to the formation and development of habitable planets than smaller galaxies, like the Milky Way galaxy. However, what makes a planet habitable is a much more complex question than having a planet located at the right distance from its host star so that water can be liquid on its surface: various geophysical and geodynamical aspects, the radiation, and the host star's plasma environment can influence the evolution of planets and life if it originated. Liquid water is a necessary but not sufficient condition for life as we know it, as habitability is a function of a multitude of environmental parameters. The spectral class of a star indicates its photospheric temperature, which (for main-sequence stars) correlates to overall mass. The appropriate spectral range for habitable stars is considered to be "late F" or "G", to "mid-K". This corresponds to temperatures of a little more than 7,000 K down to a little less than 4,000 K (6,700 °C to 3,700 °C); the Sun, a G2 star at 5,777 K, is well within these bounds. This spectral range probably accounts for between 5% and 10% of stars in the local Milky Way galaxy. "Middle-class" stars of this sort have a number of characteristics considered important to planetary habitability: K-type stars may be able to support life far longer than the Sun. Whether fainter late K and M class red dwarf stars are also suitable hosts for habitable planets is perhaps the most important open question in the entire field of planetary habitability given their prevalence (habitability of red dwarf systems). Gliese 581 c, a "super-Earth", has been found orbiting in the "habitable zone" (HZ) of a red dwarf and may possess liquid water. However, it is also possible that a greenhouse effect may render it too hot to support life, while its neighbor, Gliese 581 d, may be a more likely candidate for habitability. In September 2010, the discovery was announced of another planet, Gliese 581 g, in an orbit between these two planets. However, reviews of the discovery have placed the existence of this planet in doubt, and it is listed as "unconfirmed". In September 2012, the discovery of two planets orbiting Gliese 163 was announced. One of the planets, Gliese 163 c, about 6.9 times the mass of Earth and somewhat hotter, was considered to be within the habitable zone. A recent study suggests that cooler stars that emit more light in the infrared and near-infrared may actually host warmer planets with less ice and an incidence of snowball states. These wavelengths are absorbed by their planets' ice and greenhouse gases and remain warmer. A 2020 study found that about half of Sun-like stars could host rocky, potentially habitable planets. Specifically, they estimated that, on average, the nearest habitable zone planet around G and K-type stars is about 6 parsecs away, and there are about 4 rocky planets around G and K-type stars within 10 parsecs (32.6 light years) of the Sun. The habitable zone (HZ) is a shell-shaped region of space surrounding a star in which a planet could maintain liquid water on its surface. The concept was first proposed by astrophysicist Su-Shu Huang in 1959, based on climatic constraints imposed by the host star. After an energy source, liquid water is widely considered the most important ingredient for life, considering how integral it is to all life systems on Earth. However, if life is discovered in the absence of water, the definition of an HZ may have to be greatly expanded. The inner edge of the HZ is the distance where runaway greenhouse effect vaporizes the whole water reservoir and, as a second effect, induces the photodissociation of water vapor and the loss of hydrogen to space. The outer edge of the HZ is the distance from the star where a maximum greenhouse effect fails to keep the surface of the planet above the freezing point, and by CO2(carbon dioxide) condensation. A "stable" HZ implies two factors. First, the range of a HZ should not vary greatly over time. All stars increase in luminosity as they age, and a given HZ thus migrates outwards, but if this happens too quickly (for example, with a super-massive star) planets may only have a brief window inside the HZ and a correspondingly smaller chance of developing life. Calculating an HZ range and its long-term movement is never straightforward, as negative feedback loops such as the CNO cycle will tend to offset the increases in luminosity. Assumptions made about atmospheric conditions and geology thus have as great an impact on a putative HZ range as does stellar evolution: the proposed parameters of the Sun's HZ, for example, have fluctuated greatly. Second, no large-mass body such as a gas giant should be present in or relatively close to the HZ, thus disrupting the formation of Earth-size bodies. The matter in the asteroid belt, for example, appears to have been unable to accrete into a planet due to orbital resonances with Jupiter; if the giant had appeared in the region that is now between the orbits of Venus and Mars, Earth would almost certainly not have developed in its present form. However a gas giant inside the HZ might have habitable moons under the right conditions. Changes in luminosity are common to all stars, but the severity of such fluctuations covers a broad range. Most stars are relatively stable, but a significant minority of variable stars often undergo sudden and intense increases in luminosity and consequently in the amount of energy radiated toward bodies in orbit. These stars are considered poor candidates for hosting life-bearing planets, as their unpredictability and energy output changes would negatively impact organisms: living things adapted to a specific temperature range could not survive too great a temperature variation. Further, upswings in luminosity are generally accompanied by massive doses of gamma ray and X-ray radiation which might prove lethal. Atmospheres do mitigate such effects, but their atmosphere might not be retained by planets orbiting variables, because the high-frequency energy buffeting these planets would continually strip them of their protective covering. The Sun, in this respect as in many others, is relatively benign: the variation between its maximum and minimum energy output is roughly 0.1% over its 11-year solar cycle. There is strong (though not undisputed) evidence that even minor changes in the Sun's luminosity have had significant effects on the Earth's climate well within the historical era: the Little Ice Age of the mid-second millennium, for instance, may have been caused by a relatively long-term decline in the Sun's luminosity. Thus, a star does not have to be a true variable for differences in luminosity to affect habitability. Of known solar analogs, one that closely resembles the Sun is considered to be 18 Scorpii; unfortunately for the prospects of life existing in its proximity, the only significant difference between the two bodies is the amplitude of the solar cycle, which appears to be much greater for 18 Scorpii. While the bulk of the material in any star is hydrogen and helium, there is a significant variation in the amount of heavier elements (metals). A high proportion of metals in a star correlates to the amount of heavy material initially available in the protoplanetary disk. A smaller amount of metal makes the formation of planets much less likely, under the solar nebula theory of planetary system formation. Any planets that did form around a metal-poor star would probably be low in mass, and thus unfavorable for life. Spectroscopic studies of systems where exoplanets have been found to date confirm the relationship between high metal content and planet formation: "Stars with planets, or at least with planets similar to the ones we are finding today, are more metal-rich than stars without planetary companions." This relationship between high metallicity and planet formation also means that habitable systems are more likely to be found around stars of younger generations, since stars that formed early in the universe's history have low metal content. Planetary characteristics Habitability indicators and biosignatures must be interpreted within a planetary and environmental context. Whether a planet will emerge as habitable depends on the sequence of events that led to its formation, which could include the production of organic molecules in molecular clouds and protoplanetary disks, delivery of materials during and after planetary accretion, and the orbital location in the planetary system. The chief assumption about habitable planets is that they are terrestrial. Such planets, roughly within one order of magnitude of Earth mass, are primarily composed of silicate rocks, and have not accreted the gaseous outer layers of hydrogen and helium found on gas giants. The possibility that life could evolve in the cloud tops of giant planets has not been decisively ruled out,[c] though it is considered unlikely, as they have no surface and their gravity is enormous. The natural satellites of giant planets, meanwhile, remain valid candidates for hosting life. In February 2011 the Kepler Space Observatory Mission team released a list of 1235 extrasolar planet candidates, including 54 that may be in the habitable zone. Six of the candidates in this zone are smaller than twice the size of Earth. A more recent study found that one of these candidates (KOI 326.01) is much larger and hotter than first reported. Based on the findings, the Kepler team estimated there to be "at least 50 billion planets in the Milky Way" of which "at least 500 million" are in the habitable zone. In analyzing which environments are likely to support life, a distinction is usually made between simple, unicellular organisms such as bacteria and archaea and complex metazoans (animals). Unicellularity necessarily precedes multicellularity in any hypothetical tree of life, and where single-celled organisms do emerge there is no assurance that greater complexity will then develop.[d] The planetary characteristics listed below are considered crucial for life generally, but in every case, multicellular organisms are more picky than unicellular life. In August 2021, a new class of habitable planets, named ocean planets, which involves "hot, ocean-covered planets with hydrogen-rich atmospheres", has been reported. Hycean planets may soon be studied for biosignatures by terrestrial telescopes as well as space telescopes, such as the James Webb Space Telescope (JWST), which was launched on 25 December 2021. Low-mass planets are poor candidates for life for two reasons. First, their lesser gravity makes atmosphere retention difficult. Constituent molecules are more likely to reach escape velocity and be lost to space when buffeted by solar wind or stirred by collision. Planets without a thick atmosphere lack the matter necessary for primal biochemistry, have little insulation and poor heat transfer across their surfaces (for example, Mars, with its thin atmosphere, is colder than the Earth would be if it were at a similar distance from the Sun), and provide less protection against meteoroids and high-frequency radiation. Further, where an atmosphere is less dense than 0.006 Earth atmospheres, water cannot exist in liquid form as the required atmospheric pressure, 4.56 mm Hg (608 Pa) (0.18 inch Hg), does not occur. In addition, a lessened pressure reduces the range of temperatures at which water is liquid. Secondly, smaller planets have smaller diameters and thus higher surface-to-volume ratios than their larger cousins. Such bodies tend to lose the energy left over from their formation quickly and end up geologically dead, lacking the volcanoes, earthquakes and tectonic activity which supply the surface with life-sustaining material and the atmosphere with temperature moderators like carbon dioxide. Plate tectonics appear particularly crucial, at least on Earth: not only does the process recycle important chemicals and minerals, but it also fosters bio-diversity through continent creation and increased environmental complexity and helps create the convective cells necessary to generate Earth's magnetic field. Although geologically active planets with volcanism but no plate tectonics, called Ignan Earths, could also be habitable. "Low mass" is partly a relative label: the Earth is low mass when compared to the Solar System's gas giants, but it is the largest, by diameter and mass, and the densest of all terrestrial bodies.[e] It is large enough to retain an atmosphere through gravity alone and large enough that its molten core remains a heat engine, driving the diverse geology of the surface (the decay of radioactive elements within a planet's core is the other significant component of planetary heating). Mars, by contrast, is nearly (or perhaps totally) geologically dead and has lost much of its atmosphere. Thus it would be fair to infer that the lower mass limit for habitability lies somewhere between that of Mars and that of Earth or Venus: 0.3 Earth masses has been offered as a rough dividing line for habitable planets. However, a 2008 study by the Harvard-Smithsonian Center for Astrophysics suggests that the dividing line may be higher. Earth may in fact lie on the lower boundary of habitability: if it were any smaller, plate tectonics would be impossible. Venus, which has 85% of Earth's mass, shows no signs of tectonic activity. Conversely, "super-Earths", terrestrial planets with higher masses than Earth, would have higher levels of plate tectonics and thus be firmly placed in the habitable range. Exceptional circumstances do offer exceptional cases: Jupiter's moon Io (which is smaller than any of the terrestrial planets) is volcanically dynamic because of the gravitational stresses induced by its orbit, and its neighbor Europa may have a liquid ocean or icy slush underneath a frozen shell also due to power generated from orbiting a gas giant. Saturn's Titan, meanwhile, has an outside chance of harboring life, as it has retained a thick atmosphere and has liquid methane seas on its surface. Organic-chemical reactions that only require minimum energy are possible in these seas, but whether any living system can be based on such minimal reactions is unclear, and would seem unlikely. These satellites are exceptions, but they prove that mass, as a criterion for habitability, cannot necessarily be considered definitive at this stage of our understanding. A larger planet is likely to have a more massive atmosphere. A combination of higher escape velocity to retain lighter atoms, and extensive outgassing from enhanced plate tectonics may greatly increase the atmospheric pressure and temperature at the surface compared to Earth. The enhanced greenhouse effect of such a heavy atmosphere would tend to suggest that the habitable zone should be further out from the central star for such massive planets. Finally, a larger planet is likely to have a large iron core. This allows for a magnetic field to protect the planet from stellar wind and cosmic radiation, which otherwise would tend to strip away planetary atmosphere and bombard living things with ionized particles. Mass is not the only criterion for producing a magnetic field—as the planet must also rotate fast enough to produce a dynamo effect within its core—but it is a significant component of the process. The mass of a potentially habitable exoplanet is between 0.1 and 5.0 Earth masses. However, it is possible for a habitable world to have a mass as low as 0.0268 Earth Masses. The radius of a potentially habitable exoplanet would range between 0.5 and 1.5 Earth radii. As with other criteria, stability is the critical consideration in evaluating the effect of orbital and rotational characteristics on planetary habitability. Orbital eccentricity is the difference between a planet's farthest and closest approach to its parent star divided by the sum of said distances. It is a ratio describing the shape of the elliptical orbit. The greater the eccentricity the greater the temperature fluctuation on a planet's surface. Although they are adaptive, living organisms can stand only so much variation, particularly if the fluctuations overlap both the freezing point and boiling point of the planet's main biotic solvent (e.g., water on Earth). If, for example, Earth's oceans were alternately boiling and freezing solid, it is difficult to imagine life as we know it having evolved. The more complex the organism, the greater the temperature sensitivity. The Earth's orbit is almost perfectly circular, with an eccentricity of less than 0.02; other planets in the Solar System (with the exception of Mercury and Mars) have eccentricities that are similarly benign. Habitability is also influenced by the architecture of the planetary system around a star. The evolution and stability of these systems are determined by gravitational dynamics, which drive the orbital evolution of terrestrial planets. Data collected on the orbital eccentricities of extrasolar planets has surprised most researchers: 90% have an orbital eccentricity greater than that found within the Solar System, and the average is fully 0.25. This means that the vast majority of planets have highly eccentric orbits and of these, even if their average distance from their star is deemed to be within the HZ, they nonetheless would be spending only a small portion of their time within the zone. A planet's movement around its rotational axis must also meet certain criteria if life is to have the opportunity to evolve. A first assumption is that the planet should have moderate seasons. If there is little or no axial tilt (or obliquity) relative to the perpendicular of the ecliptic, seasons will not occur and a main stimulant to biospheric dynamism will disappear. The planet would also be colder than it would be with a significant tilt: when the greatest intensity of radiation is always within a few degrees of the equator, warm weather cannot move poleward and a planet's climate becomes dominated by colder polar weather systems. If a planet is radically tilted, seasons will be extreme and make it more difficult for a biosphere to achieve homeostasis. The axial tilt of the Earth is higher now (in the Quaternary) than it has been in the past, coinciding with reduced polar ice, warmer temperatures, and less seasonal variation. Scientists do not know whether this trend will continue indefinitely with further increases in axial tilt (see Snowball Earth). The exact effects of these changes can only be computer modelled at present, and studies have shown that even extreme tilts of up to 85 degrees do not absolutely preclude life "provided it does not occupy continental surfaces plagued seasonally by the highest temperature." Not only the mean axial tilt, but also its variation over time must be considered. The Earth's tilt varies between 21.5 and 24.5 degrees over 41,000 years. A more drastic variation, or a much shorter periodicity, would induce climatic effects such as variations in seasonal severity. Other orbital considerations include: The Earth's Moon appears to play a crucial role in moderating the Earth's climate by stabilising the axial tilt. It has been suggested that a chaotic tilt may be a "deal-breaker" in terms of habitability—i.e. a satellite the size of the Moon is not only helpful but required to produce stability. This position remains controversial.[f] In the case of the Earth, the sole Moon is sufficiently massive and orbits so as to significantly contribute to ocean tides, which in turn aids the dynamic churning of Earth's large liquid water oceans. These lunar forces not only help ensure that the oceans do not stagnate, but also play a critical role in Earth's dynamic climate. Concentrations of radionuclides in rocky planet mantles may be critical for the habitability of Earth-like planets. Such planets with higher abundances likely lack a persistent dynamo for a significant fraction of their lifetimes, and those with lower concentrations may often be geologically inert. Planetary dynamos create strong magnetic fields which may often be necessary for life to develop or persist as they shield planets from solar winds and cosmic radiation. The electromagnetic emission spectra of stars could be used to identify those which are more likely to host habitable Earth-like planets. As of 2020, radionuclides are thought to be produced by rare stellar processes such as neutron star mergers. Additional geological characteristics may be essential or major factors in the habitability of natural celestial bodies – including some that may shape the body's heat and magnetic field. Some of these are unknown or not well understood and being investigated by planetary scientists, geochemists and others.[additional citation(s) needed] It is generally assumed that any extraterrestrial life that might exist will be based on the same fundamental biochemistry as found on Earth, as the four elements most vital for life, carbon, hydrogen, oxygen, and nitrogen, are also the most common chemically reactive elements in the universe. Indeed, simple biogenic compounds, such as very simple amino acids such as glycine, have been found in meteorites and in the interstellar medium. These four elements together comprise over 96% of Earth's collective biomass. Carbon has an unparalleled ability to bond with itself and to form a massive array of intricate and varied structures, making it an ideal material for the complex mechanisms that form living cells. Hydrogen and oxygen, in the form of water, compose the solvent in which biological processes take place and in which the first reactions occurred that led to life's emergence. The energy released in the formation of powerful covalent bonds between carbon and oxygen, available by oxidizing organic compounds, is the fuel of all complex life-forms. These four elements together make up amino acids, which in turn are the building blocks of proteins, the substance of living tissue. In addition, neither sulfur (required for the building of proteins) nor phosphorus (needed for the formation of DNA, RNA, and the adenosine phosphates essential to metabolism) are rare. Relative abundance in space does not always mirror differentiated abundance within planets; of the four life elements, for instance, only oxygen is present in any abundance in the Earth's crust. This can be partly explained by the fact that many of these elements, such as hydrogen and nitrogen, along with their simplest and most common compounds, such as carbon dioxide, carbon monoxide, methane, ammonia, and water, are gaseous at warm temperatures. In the hot region close to the Sun, these volatile compounds could not have played a significant role in the planets' geological formation. Instead, they were trapped as gases underneath the newly formed crusts, which were largely made of rocky, involatile compounds such as silica (a compound of silicon and oxygen, accounting for oxygen's relative abundance). Outgassing of volatile compounds through the first volcanoes would have contributed to the formation of the planets' atmospheres. The Miller–Urey experiment showed that, with the application of energy, simple inorganic compounds exposed to a primordial atmosphere can react to synthesize amino acids. Even so, volcanic outgassing could not have accounted for the amount of water in Earth's oceans. The vast majority of the water—and arguably carbon—necessary for life must have come from the outer Solar System, away from the Sun's heat, where it could remain solid. Comets impacting with the Earth in the Solar System's early years would have deposited vast amounts of water, along with the other volatile compounds life requires, onto the early Earth, providing a kick-start to the origin of life. Thus, while there is reason to suspect that the four "life elements" ought to be readily available elsewhere, a habitable system probably also requires a supply of long-term orbiting bodies to seed inner planets. Without comets there is a possibility that life as we know it would not exist on Earth. One important qualification to habitability criteria is that only a tiny portion of a planet is required to support life, a so-called Goldilocks Edge or Great Prebiotic Spot. Astrobiologists often concern themselves with "micro-environments", noting that "we lack a fundamental understanding of how evolutionary forces, such as mutation, selection, and genetic drift, operate in micro-organisms that act on and respond to changing micro-environments." Extremophiles are Earth organisms that live in niche environments under severe conditions generally considered inimical to life. Usually (although not always) unicellular, extremophiles include acutely alkaliphilic and acidophilic organisms and others that can survive water temperatures above 100 °C in hydrothermal vents. The discovery of life in extreme conditions has complicated definitions of habitability, but also generated much excitement amongst researchers in greatly broadening the known range of conditions under which life can persist. For example, a planet that might otherwise be unable to support an atmosphere given the solar conditions in its vicinity, might be able to do so within a deep shadowed rift or volcanic cave. Similarly, craterous terrain might offer a refuge for primitive life. The Lawn Hill crater has been studied as an astrobiological analog, with researchers suggesting rapid sediment infill created a protected microenvironment for microbial organisms; similar conditions may have occurred over the geological history of Mars. Earth environments that cannot support life are still instructive to astrobiologists in defining the limits of what organisms can endure. The heart of the Atacama Desert, generally considered the driest place on Earth, appears unable to support life, and it has been subject to study by NASA and ESA for that reason: it provides a Mars analog and the moisture gradients along its edges are ideal for studying the boundary between sterility and habitability. The Atacama was the subject of study in 2003 that partly replicated experiments from the Viking landings on Mars in the 1970s; no DNA could be recovered from two soil samples, and incubation experiments were also negative for biosignatures. The two current ecological approaches for predicting the potential habitability use 19 or 20 environmental factors, with emphasis on water availability, temperature, presence of nutrients, an energy source, and protection from solar ultraviolet and galactic cosmic radiation. The Habitable Exoplanets Catalog uses estimated surface temperature range to classify exoplanets: Mesoplanets would be ideal for complex life, whereas hypopsychroplanets and hyperthermoplanets might only support extremophilic life. The HEC uses the following terms to classify exoplanets in terms of mass, from least to greatest: asteroidan, mercurian, subterran, terran, superterran, neptunian, and jovian. Alternative star systems In determining the feasibility of extraterrestrial life, astronomers had long focused their attention on stars like the Sun. However, since planetary systems that resemble the Solar System are proving to be rare, they have begun to explore the possibility that life might form in systems very unlike the Sun's. It is believed that F, G, K and M-type stars could host habitable exoplanets. About half of the stars similar in temperature to the Sun could have a rocky planet able to support liquid water on its surface, according to research using data from NASA's Kepler Space Telescope. Typical estimates often suggest that 50% or more of all stellar systems are binary systems. This may be partly sample bias, as massive and bright stars tend to be in binaries and these are most easily observed and catalogued; a more precise analysis has suggested that the more common fainter stars are usually singular, and that up to two thirds of all stellar systems are therefore solitary. The separation between stars in a binary may range from less than one astronomical unit (AU, the average Earth–Sun distance) to several hundred. In latter instances, the gravitational effects will be negligible on a planet orbiting an otherwise suitable star and habitability potential will not be disrupted unless the orbit is highly eccentric. However, where the separation is significantly less, a stable orbit may be impossible. If a planet's distance to its primary exceeds about one fifth of the closest approach of the other star, orbital stability is not guaranteed. Whether planets might form in binaries at all had long been unclear, given that gravitational forces might interfere with planet formation. Theoretical work by Alan Boss at the Carnegie Institution has shown that gas giants can form around stars in binary systems much as they do around solitary stars. One study of Alpha Centauri, the nearest star system to the Sun, suggested that binaries need not be discounted in the search for habitable planets. Centauri A and B have an 11 AU distance at closest approach (23 AU mean), and both should have stable habitable zones. A study of long-term orbital stability for simulated planets within the system shows that planets within approximately three AU of either star may remain rather stable (i.e. the semi-major axis deviating by less than 5% during 32 000 binary periods). The continuous habitable zone (CHZ for 4.5 billion years) for Centauri A is conservatively estimated at 1.2 to 1.3 AU and Centauri B at 0.73 to 0.74—well within the stable region in both cases. M-type stars also considered possible hosts of habitable exoplanets, even those with flares such as Proxima b. Determining the habitability of red dwarf stars could help determine how common life in the universe might be, as red dwarfs make up between 70 and 90% of all the stars in the galaxy. However, it is important to bear in mind that flare stars could greatly reduce the habitability of exoplanets by eroding their atmosphere. Astronomers for many years ruled out red dwarfs as potential abodes for life. Their small size (from 0.08 to 0.45 solar masses) means that their nuclear reactions proceed exceptionally slowly, and they emit very little light (from 3% of that produced by the Sun to as little as 0.01%). Any planet in orbit around a red dwarf would have to huddle very close to its parent star to attain Earth-like surface temperatures; from 0.3 AU (just inside the orbit of Mercury) for a star like Lacaille 8760, to as little as 0.032 AU for a star like Proxima Centauri (such a world would have a year lasting just 6.3 days). At those distances, the star's gravity would cause tidal locking. One side of the planet would eternally face the star, while the other would always face away from it. The only ways in which potential life could avoid either an inferno or a deep freeze would be if the planet had an atmosphere thick enough to transfer the star's heat from the day side to the night side, or if there was a gas giant in the habitable zone, with a habitable moon, which would be locked to the planet instead of the star, allowing a more even distribution of radiation over the moon. It was long assumed that such a thick atmosphere would prevent sunlight from reaching the surface in the first place, preventing photosynthesis. This pessimism has been tempered by research. Studies by Robert Haberle and Manoj Joshi of NASA's Ames Research Center in California have shown that a planet's atmosphere (assuming it included greenhouse gases CO2 and H2O) need only be 100 millibars (0.10 atm), for the star's heat to be effectively carried to the night side. This is well within the levels required for photosynthesis, though water would still remain frozen on the dark side in some of their models. Martin Heath of Greenwich Community College, has shown that seawater, too, could be effectively circulated without freezing solid if the ocean basins were deep enough to allow free flow beneath the night side's ice cap. Further research—including a consideration of the amount of photosynthetically active radiation—suggested that tidally locked planets in red dwarf systems might at least be habitable for higher plants. Size is not the only factor in making red dwarfs potentially unsuitable for life, however. On a red dwarf planet, photosynthesis on the night side would be impossible, since it would never see the sun. On the day side, because the sun does not rise or set, areas in the shadows of mountains would remain so forever. Photosynthesis as we understand it would be complicated by the fact that a red dwarf produces most of its radiation in the infrared, and on the Earth the process depends on visible light. There are potential positives to this scenario. Numerous terrestrial ecosystems rely on chemosynthesis rather than photosynthesis, for instance, which would be possible in a red dwarf system. A static primary star position removes the need for plants to steer leaves toward the sun, deal with changing shade/sun patterns, or change from photosynthesis to stored energy during night. Because of the lack of a day-night cycle, including the weak light of morning and evening, far more energy would be available at a given radiation level. Red dwarfs are far more variable and violent than their more stable, larger cousins. Often they are covered in starspots that can dim their emitted light by up to 40% for months at a time, while at other times they emit gigantic flares that can double their brightness in a matter of minutes. Such variation would be very damaging for life, as it would not only destroy any complex organic molecules that could possibly form biological precursors, but also because it would blow off sizeable portions of the planet's atmosphere. For a planet around a red dwarf star to support life, it would require a rapidly rotating magnetic field to protect it from the flares. A tidally locked planet rotates only very slowly, and so cannot produce a geodynamo at its core. The violent flaring period of a red dwarf's life cycle is estimated to only last roughly the first 1.2 billion years of its existence. If a planet forms far away from a red dwarf so as to avoid tidal locking, and then migrates into the star's habitable zone after this turbulent initial period, it is possible that life may have a chance to develop. However, observations of the 7 to 12-billion year old Barnard's Star showcase that even old red dwarfs can have significant flare activity. Barnard's Star was long assumed to have little activity, but in 1998 astronomers observed an intense stellar flare, showing that it is a flare star. Red dwarfs have one advantage over other stars as abodes for life: far greater longevity. It took 4.5 billion years before humanity appeared on Earth, and life as we know it will see suitable conditions for 1 to 2.3 billion years more. Red dwarfs, by contrast, could live for trillions of years because their nuclear reactions are far slower than those of larger stars, meaning that life would have longer to evolve and survive. While the likelihood of finding a planet in the habitable zone around any specific red dwarf is slight, the total amount of habitable zone around all red dwarfs combined is equal to the total amount around Sun-like stars given their ubiquity. Furthermore, this total amount of habitable zone will last longer, because red dwarf stars live for hundreds of billions of years or even longer on the main sequence. However, combined with the above disadvantages, it is more likely that red dwarf stars would remain habitable longer to microbes, while the shorter-lived yellow dwarf stars, like the Sun, would remain habitable longer to animals. Some A and B type stars that have protoplanetary disks (especially Herbig Ae/Be stars) may form habitable planets. The star’s lifespan is short, but the habitable zone is wide, so it may be the planets become habitable for a short period of time. (about thousands or a million years) For the list of the A and B type stars with protoplanetary disks, see A-type main-sequence star and B-type main-sequence star. Recent research suggests that very large stars, greater than ~100 solar masses, could have planetary systems consisting of hundreds of Mercury-sized planets within the habitable zone. Such systems could also contain brown dwarfs and low-mass stars (~0.1–0.3 solar masses). However the very short lifespans of stars of more than a few solar masses would scarcely allow time for a planet to cool, let alone the time needed for a stable biosphere to develop. Massive stars are thus eliminated as possible abodes for life. However, a massive-star system could be a progenitor of life in another way – the supernova explosion of the massive star in the central part of the system. This supernova will disperse heavier elements throughout its vicinity, created during the phase when the massive star has moved off of the main sequence, and the systems of the potential low-mass stars (which are still on the main sequence) within the former massive-star system may be enriched with the relatively large supply of the heavy elements so close to a supernova explosion. However, this states nothing about what types of planets would form as a result of the supernova material, or what their habitability potential would be. Four classes of habitable planets based on water In a review of the factors which are important for the evolution of habitable Earth-sized planets, Lammer et al. proposed a classification of four water-dependent habitat types: Class I habitats are planetary bodies on which stellar and geophysical conditions allow liquid water to be available at the surface, along with sunlight, so that complex multicellular organisms may originate. Class II habitats include bodies which initially enjoy Earth-like conditions, but do not keep their ability to sustain liquid water on their surface due to stellar or geophysical conditions. Mars, and possibly Venus are examples of this class where complex life forms may not develop. Class III habitats are planetary bodies where liquid water oceans exist below the surface, where they can interact directly with a silicate-rich core. Class IV habitats have liquid water layers between two ice layers, or liquids above ice. The galactic neighborhood Along with the characteristics of planets and their star systems, the wider galactic environment may also impact habitability. Scientists considered the possibility that particular areas of galaxies (galactic habitable zones) are better suited to life than others; the Solar System, in the Orion Arm, on the Milky Way galaxy's edge is considered to be in a life-favorable spot: Thus, relative isolation is ultimately what a life-bearing system needs. If the Sun were crowded amongst other systems, the chance of being fatally close to dangerous radiation sources would increase significantly. Further, close neighbors might disrupt the stability of various orbiting bodies such as Oort cloud and Kuiper belt objects, which can bring catastrophe if knocked into the inner Solar System. While stellar crowding proves disadvantageous to habitability, so too does extreme isolation. A star as metal-rich as the Sun would probably not have formed in the very outermost regions of the Milky Way given a decline in the relative abundance of metals and a general lack of star formation. Thus, a "suburban" location, such as the Solar System enjoys, is preferable to a Galaxy's center or farthest reaches. Other considerations While most investigations of extraterrestrial life start with the assumption that advanced life-forms must have similar requirements for life as on Earth, the hypothesis of other types of biochemistry suggests the possibility of lifeforms evolving around a different metabolic mechanism. In Evolving the Alien, biologist Jack Cohen and mathematician Ian Stewart argue astrobiology, based on the Rare Earth hypothesis, is restrictive and unimaginative. They suggest that Earth-like planets may be very rare, but non-carbon-based complex life could possibly emerge in other environments. The most frequently mentioned alternative to carbon is silicon-based life, while ammonia and hydrocarbons are sometimes suggested as alternative solvents to water. The astrobiologist Dirk Schulze-Makuch and other scientists have proposed a Planet Habitability Index whose criteria include "potential for holding a liquid solvent" that is not necessarily restricted to water. More speculative ideas have focused on bodies altogether different from Earth-like planets. Astronomer Frank Drake, a well-known proponent of the search for extraterrestrial life, imagined life on a neutron star: submicroscopic "nuclear molecules" combining to form creatures with a life cycle millions of times quicker than Earth life. Called "imaginative and tongue-in-cheek", the idea gave rise to science fiction depictions. Carl Sagan, another optimist with regards to extraterrestrial life, considered the possibility of organisms that are always airborne within the high atmosphere of Jupiter in a 1976 paper. Cohen and Stewart also envisioned life in both a solar environment and in the atmosphere of a gas giant. "Good Jupiters" are gas giants, like the Solar System's Jupiter, that orbit their stars in circular orbits far enough away from the habitable zone not to disturb it but close enough to "protect" terrestrial planets in closer orbit in two critical ways. First, they help to stabilize the orbits, and thereby the climates of the inner planets. Second, they keep the inner stellar system relatively free of comets and asteroids that could cause devastating impacts. Jupiter orbits the Sun at about five times the distance between the Earth and the Sun. This is the rough distance we should expect to find good Jupiters elsewhere. Jupiter's "caretaker" role was dramatically illustrated in 1994 when Comet Shoemaker–Levy 9 impacted the giant.[according to whom?] However, the evidence is not quite so clear. Research has shown that Jupiter's role in determining the rate at which objects hit Earth is significantly more complicated than once thought. The role of Jupiter in the early history of the Solar System is somewhat better established, and the source of significantly less debate. Early in the Solar System's history, Jupiter is accepted as having played an important role in the hydration of our planet: it increased the eccentricity of asteroid belt orbits and enabled many to cross Earth's orbit and supply the planet with important volatiles such as water and carbon dioxide. Before Earth reached half its present mass, icy bodies from the Jupiter–Saturn region and small bodies from the primordial asteroid belt supplied water to the Earth due to the gravitational scattering of Jupiter and, to a lesser extent, Saturn. Thus, while the gas giants are now helpful protectors, they were once suppliers of critical habitability material. In contrast, Jupiter-sized bodies that orbit too close to the habitable zone but not in it (as in 47 Ursae Majoris), or have a highly elliptical orbit that crosses the habitable zone (like 16 Cygni B) make it very difficult for an independent Earth-like planet to exist in the system. See the discussion of a stable habitable zone above. However, during the process of migrating into a habitable zone, a Jupiter-size planet may capture a terrestrial planet as a moon. Even if such a planet is initially loosely bound and following a strongly inclined orbit, gravitational interactions with the star can stabilize the new moon into a close, circular orbit that is coplanar with the planet's orbit around the star. A supplement to the factors that support life's emergence is the notion that life itself, once formed, becomes a habitability factor in its own right. An important Earth example was the production of molecular oxygen gas (O2) by ancient cyanobacteria, and eventually photosynthesizing plants, leading to a radical change in the composition of Earth's atmosphere. This environmental change is called the Great Oxidation Event. This oxygen proved fundamental to the respiration of later animal species. The Gaia hypothesis, a scientific model of the geo-biosphere pioneered by James Lovelock in 1975, argues that life as a whole fosters and maintains suitable conditions for itself by helping to create a planetary environment suitable for its continuity. Similarly, David Grinspoon has suggested a "living worlds hypothesis" in which our understanding of what constitutes habitability cannot be separated from life already extant on a planet. Planets that are geologically and meteorologically alive are much more likely to be biologically alive as well and "a planet and its life will co-evolve." This is the basis of Earth system science. In 2020, a computer simulation of the evolution of planetary climates over 3 billion years suggested that feedback is a necessary but insufficient condition for preventing planets from ever becoming too hot or cold for life. Chance also plays a crucial role. Related considerations include yet unknown factors influencing the thermal habitability of planets such as "feedback mechanism (or mechanisms) that prevents the climate ever wandering to fatal temperatures". See also Notes References Bibliography Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Quest_Pro] | [TOKENS: 1620] |
Contents Meta Quest Pro USB-C The Meta Quest Pro is a discontinued mixed reality (MR) headset developed by Reality Labs, a division of Meta Platforms. Unveiled on October 11, 2022, it is a high-end headset designed for mixed reality and virtual reality applications, targeting business and enthusiast users. It is differentiated from the Quest 2 by a thinner form factor leveraging pancake lenses, high resolution cameras for MR, integrated face and eye tracking, and updated controllers with on-board motion tracking. The Quest Pro received mixed reviews, with critics praising its display and controllers, but criticizing its mixed reality cameras for having a grainy appearance and limited usefulness in its software at launch, and for its high price. Meta discontinued the Quest Pro in favor of the Meta Quest 3 in September 2024, with sales ending in January 2025. Development Prior to Facebook Connect in October 2021 (during which Facebook, Inc. announced its rebranding as "Meta" to emphasize its development of "metaverse"-related technologies), CEO Mark Zuckerberg and CTO Andrew Bosworth posted photos of themselves testing prototype headsets, which they stated to have "Retina resolution" displays (alluding to the Apple Inc. trademark for high-resolution displays), while leaked demo videos and references to an "Oculus Pro" headset were also discovered on the Oculus website and unreleased system software. During the event, Zuckerberg officially announced that the company was developing a headset codenamed "Project Cambria" as part of the Oculus Quest line of products, which would be a high-end product aimed at mixed reality applications, and feature a slimmer design, high-resolution color passthrough cameras, infrared depth sensors, and eye tracking. The product was officially revealed as Meta Quest Pro during Connect in October 2022 for a release on October 25; Zuckerberg told the media that the Quest Pro would target "people who just want the highest-end VR device – enthusiast, prosumer folks – or people who are trying to get work done", and would be sold in parallel with the Quest 2 (which is aimed primarily at the consumer market). Bosworth stated that the Quest Pro would "take existing experiences that people are having today in VR and make them better." The planned depth sensor was dropped from the final hardware due to cost and weight concerns. Specifications The Quest Pro more closely resembles AR headsets such as Microsoft's HoloLens rather than other VR headsets, with a thinner lens enclosure, and a more visor-like form factor that does not obscure the entirety of the user's peripheral vision; "peripheral blinders" are included as an accessory, with a "full light blocker" attachment sold separately. The lenses can be adjusted for interpupillary distance, and moved forwards and backwards. It uses LCD quantum dot displays with a per-eye resolution of 1800×1920, viewed through pancake lenses that allow for its enclosure to be 40% thinner in comparison to the Quest 2. Meta stated that the displays supported a wider color gamut than the Quest 2, and had improved contrast via "local dimming". The Quest Pro's battery is built into the back of its head strap for better weight distribution; Meta rated it as lasting 1 to 2 hours on a single charge. For its mixed reality functions, the Quest Pro uses high-resolution color cameras, as opposed to the lower-resolution, grayscale cameras on the Quest. The headset also contains internal sensors that are used for eye and face tracking, primarily for use with avatars. The Quest Pro uses a Qualcomm Snapdragon XR2+ system-on-chip with 12 GB of RAM, which Meta stated had "50% more power" than the Quest 2's Snapdragon XR. The Quest Pro uses Touch Pro controllers, a significant update to the Oculus Touch controllers used by prior Quest and Rift products. They have a more compact design with upgraded haptics, and replace the infrared sensor ring (which were tracked by the headset's cameras) with on-board motion tracking using embedded cameras and Qualcomm Snapdragon 662 processors. The controllers are also rechargeable via the headset's charging dock, have a new pressure sensor for pinch gestures, and have pressure-sensitive stylus tip accessories that can be attached to the bottoms of their handles for drawing and writing. The Quest Pro controllers are also sold separately as an accessory for Quest 2 and newer. The Quest Pro was demonstrated to the press with mixed reality versions of software such as Horizon Workrooms (which allows users to attend meetings, and control their computer remotely in VR with a virtual multi-monitor environment), the DJ software Tribe XR, and Painting VR. Meta announced a partnership with Microsoft to integrate productivity services such as Microsoft 365, Microsoft Teams, and Windows 365 with Meta Quest 2 and Pro, including allowing users to join Teams meetings via Horizon Workrooms, use Microsoft 365 applications, as well as support for management of Quest devices via Intune. In December 2023, Valve Corporation released Steam Link for Meta Quest 2, Quest Pro, and Quest 3, with OSC support for facial and eye tracking on Quest Pro. Reception The Quest Pro received mixed reviews. Ars Technica noted that its design felt less "claustrophobic" and "much more secure and better balanced than previous Quest headsets, especially during extended use", but noting that its narrow field of view was more apparent when using the headset without its light blinder accessories. Its display and lenses were described as being slightly sharper and having more legible text rendering than the Quest 2, making it better-suited for office tasks and using a remote desktop environment in Workrooms. The MR cameras were panned for being grainy and "fuzzy"-looking, while many of the MR features in apps at launch were deemed to be "novelties". It was also criticized for requiring manual room setup, rather than automatically mapping walls. In conclusion, it was felt that "at its current asking price, though, we can only recommend the Quest Pro to mid-level executives who have convinced their superiors to allocate a ridiculous, money-is-no-object budget to ill-defined metaverse projects out of nothing more than a deep sense of FOMO." Adi Robertson of The Verge described the device as "seemingly launched without plan or purpose, highlighting VR’s persistent drawbacks without making good use of its strengths — and topped off with some irredeemably bad software". The new controllers were praised for being more compact than the previous Oculus Touch design and offering a charging dock with rechargeable batteries (albeit having less battery life than the previous controllers, which used standard AA batteries). The Quest Pro was criticized for having a "uniquely tortuous" strap system that felt worse when using the headset for extended sessions (in comparison to the Quest 2 with its Elite Strap accessory), a "grainy"-looking display and "fuzzy" passthrough visuals that "doesn't look remotely like the real world", and "limited and idiosyncratic" face tracking. The Workrooms app was also criticized for being unreliable, especially for software that was promoted as being one of the key selling points of the Quest Pro. Robertson gave the Quest Pro a 2 out of 5, arguing that it "[offers] technically innovative features without doing a good job of showcasing them", and suggesting that mainstream users wait for an eventual Quest 3 that may incorporate hardware improvements from the Pro at a lower price point. In March 2023, Meta lowered the price of Quest Pro to US$1,000, amid reports of "underwhelming" sales. On July 19, 2023, The Information reported that Meta was in the process of discontinuing production of the Quest Pro, and had scrapped plans for a successor model. Meta officially discontinued the Quest Pro in September 2024 alongside the unveiling of the Meta Quest 3S, with sales officially discontinued in January 2025, and Meta steering customers towards the Meta Quest 3. References |
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[SOURCE: https://en.wikipedia.org/wiki/Ron_Miller_(artist_and_author)] | [TOKENS: 1009] |
Contents Ron Miller (artist and author) Ron Miller (born May 8, 1947) is an American illustrator and writer who lives and works in South Boston, Virginia. He now specializes in astronomical, astronautical and science fiction books for adults and young adults. Miller was born in Minneapolis, Minnesota. He holds a BFA from Columbus, Ohio, College of Art and Design. He worked as a commercial artist and designer for six years, before taking a position as art director for the National Air and Space Museum's Albert Einstein Planetarium. He left there in 1977 to become a freelance illustrator and author; to date he has nearly sixty book titles to his credit, and his illustrations have appeared on hundreds of book jackets, book interiors and in magazines such as Reader's Digest, Scientific American, Smithsonian, Analog, Starlog, Air & Space, Astronomy, Sky & Telescope, Science et Vie, Newsweek, Natural History, Discover, GEO and others. and Journey to the Center of the Earth as well as a companion/atlas to Verne's works, Extraordinary Voyages. He has acted as a consultant on Verne for Walt Disney Imagineering (for the Paris Disneyland) and A&E Television Network's Biography series. Miller's book The Dream Machines, a comprehensive 744-page history of crewed spacecraft, was nominated for the International Astronautical Federation's Manuscript Award and won the Booklist Editor's Choice Award. His original paintings are in numerous private and public collections, including the Smithsonian Institution and the Pushkin Museum (Moscow). He designed a set of ten commemorative postage stamps for the U.S. Postal Service. One of the stamps in the Space Exploration series (1991), is credited with helping inspire the New Horizons mission to that planet. The Pluto stamp was attached to the spacecraft before launch. The stamp is now in the Guinness Book of World Records as having traveled further than any other postage stamp in history.[citation needed] He has been a production illustrator for motion pictures, notably Dune and an unproduced version of Total Recall; and he designed and co-wrote the computer-generated show ride film, Comet Impact! for SimEx. He has provided concept and special effects art for numerous other directors. Most recently he was a co-producer of the documentary film, "A Brush With the Future." Miller has taken part in international space art workshops and exhibitions, including seminal sessions held in Iceland and the Soviet Union. He was invited by the Soviet government to the 30th anniversary celebration of the launch of Sputnik, and has lectured on space art and space history in the United States, France, Japan, Italy and Great Britain. He was featured on Hour 25 Science Fiction Radio program in early 2003. An authority on the work of astronomical artist Chesley Bonestell, his book The Art of Chesley Bonestell received a Hugo Award in 2002. A feature-length documentary based on this book, "A Brush With the Future," for which he was co-producer, won the Audience Award at the Newport Beach Film Festival and Best Documentary at San Diego Comic-Con. Other books have received awards, including a Silver Award for best fiction from ForeWord magazine for Palaces & Prisons and the Violet Crown Award from the Writers' League of Texas for Bradamant. His Worlds Beyond series received the American Institute of Physics Award of Excellence. The Grand Tour has gone through three editions, multiple printings, several translations, was a Hugo Award nominee and has sold over 250,000 copies. It was also twice a Book-of-the-Month feature selection. This and other books have been selections of the Science, Quality Paperback and Science Fiction Book Clubs. His book, Digital Art, was listed on the VOYA (Voice of Youth Advocates) Nonfiction Honor List in 2009. In all, he has 75 works in 142 publications in 6 languages in 16,977 libraries world-wide. In addition to his novels he has had several short stories anthologized. A series of short stories based on the title character of his novel, Velda, have been published monthly in Black Cat Magazine with twenty stories published to date. Miller has been on the faculty of the International Space University. He is a contributing editor for Air & Space/Smithsonian magazine; a member of the International Academy of Astronautics; a member of the History Committee of the American Astronautical Society; a Life Member, Fellow and past Trustee of the International Association of Astronomical Artists; member Private Eye Writers of America; an Honorary Member of the Sociétè Jules Verne [fr] (Paris); a past member of the North American Jules Verne Society and a past Fellow of the British Interplanetary Society. A recent project has been Black Cat Press, which Miller has devoted to publishing new editions of rare and obscure science fiction, fantasy and science fact books. Published books Awards References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Maor_Farid#Education_and_academic_career] | [TOKENS: 1458] |
Contents Maor Farid Dr. Maor Farid (Hebrew: מאור פריד; born April 20, 1992) is an Israeli scientist, engineer and artificial intelligence researcher at Massachusetts Institute of Technology, social activist, and author. He is the founder and CEO of Learn to Succeed (Hebrew: ללמוד להצליח) for empowering of youths from the Israeli socio-economic periphery and youths at risk, a regional manager of the Israeli center of ScienceAbroad at MIT, and an activist in the American Technion Society. He is an alumnus of Unit 8200, and a fellow of Fulbright Program and the Israel Scholarship Educational Foundation [he]. Dr. Farid was elected to the Forbes 30 Under 30 list of 2019, and won the Moskowitz Prize for Zionism. Early life Maor was born in Ness Ziona, a city in central Israel, as the eldest son for parents from immigrating families of Mizrahi Jews from Iraq and Libya. Maor suffered from Attention deficit hyperactivity disorder (ADHD) from a young age, and was classified as a problematic and violent student. His ADHD issues were diagnosed only after he began his university studies. However, inspired by his parents' background, he aspired to excel at school for a better future for his family. During elementary school, Maor attended local quizzes about Jewish history and Zionism, which significantly shaped his identity and national perspective. Farid graduated high school with the highest GPA in school. Later he was recruited to the Israel Defense Forces and drafted to the Brakim Program [he] – an excellence program of the Israeli Intelligence Corps for training leading R&D officers for the Israeli military and defense industry. Maor graduated the program with honors and was elected by the Israeli Prime Minister's Office and Unit 8200, where he served as an artificial intelligence researcher, officer, and commander. During his Military service, he received various honors and awards, such as the Excellent Scientist Award, given to the top three academics serving in the Israel Defense Forces. In 2019, Farid completed his military service in the rank of a Captain. Education and academic career As part of the (4 years) Brakim Program, Maor completed his Bachelor's and Master's degrees at the Technion in Mechanical Engineering with honors. Then, he initiated his Ph.D. research as a collaboration with the Israel Atomic Energy Commission (IAEC) in parallel to his duty military service. The main goals of his Ph.D. research were predicting irreversible effects of major earthquakes on Israel's nuclear facilities, and improving their seismic resistance using energy absorption technologies. The mathematical models developed by Farid were able to forecast earthquake effects on facilities with major hazard potential, and predicted the failure of liquid storage tanks due to earthquakes took place in Italy (2012) and Mexico (2017). The energy absorption technologies used, increased in up to 90% the seismic resistance abilities of those sensitive facilities. The research results were published in multiple papers in peer-reviewed academic journals and presented in international academic conferences. Later, this research expanded to an official collaboration between the Technion and the Shimon Peres Negev Nuclear Research Center, which aims to implement the findings obtained on existing sensitive systems, and won funding of 1.5 million NIS from the Pazy foundation of the Israel Atomic Energy Commission and the Council for Higher Education. In 2017, Farid completed his Ph.D. and as the youngest graduate at the Technion for that year, at the age of 24. In the graduation ceremonies, he honored his parents to receive the diplomas on his behalf. At the same year, he served as a lecturer at Ben-Gurion University in an original course he developed as a solution for knowledge gaps he identified in the Israeli defense industry. In 2018, Dr. Farid served as an artificial intelligence researcher at a Data Science team of Unit 8200, where he developed machine learning-based solutions for military and operational needs. In 2019, Farid won the Fulbright and the Israel Scholarship Educational Foundation scholarships, and was accepted to post-doctoral position at Massachusetts Institute of Technology where he develops real-time methods for predicting earthquake effects using machine learning techniques. In 2020, Farid was accepted to the Emerging Leaders Program at Harvard Kennedy School in Cambridge, Massachusetts. At the same year, he received the excellence research grant of the Israel Academy of Sciences and Humanities for leading his research in collaboration between MIT and the Technion. Social activism Farid social activism focuses on empowering youths from disadvantaged backgrounds from an early age. In 2010–2015, he served as a mentor of a robotics team from Dimona in FIRST Robotics Competition, a mathematics tutor in "Aharai!" [he] program for high-school students at risk in Dimona and Be'er Sheva, and a mentor and private tutor of adolescence and reserve duty soldiers from disadvantaged backgrounds. In 2010, he initiated "Learn to Succeed" (Hebrew: ללמוד להצליח) project, for mitigating the social gaps in the Israeli society by empowering youths from the social, economical, and geographical periphery for excellence, self-fulfillment and gaining formal education. In 2018, Learn to Succeed became an official non-profit organization. At the same year, Farid led a crowdfunding project of 150,000 NIS in order to expand the organization to a national scale. In 2019, he published the book "Learn to Succeed", in which he describes his struggle with ADHD, the violent environment in which he grew up, and the changing process he went through from being a violent teenager to becoming the youngest Ph.D. graduate at the Technion. The book was given to more than two thousand youths at risk and became a top seller in Israel shortly after its publication. Maor dedicated the book to his parents and to the memorial of his friend Captain Tal Nachman who was killed in operational activity during his military service in 2014. The organization consists of hundreds of volunteers, gives full scholarships to STEM students from the periphery who serve as mentors of youths, both Jews and Arabs, from disadvantaged backgrounds, runs a hotline which gives online practical and mental support to hundreds of youths, parents and educators, initiates inspirational activities with military orientation to increase the motivation of its teen-age members for significant military service, and gives inspirational lectures to more than 5,000 youths each year. In 2019, Maor initiated a collaboration with Unit 8200 in which tens of the program's members are being interviewed to the unit. This opportunity is usually given to students with the highest grades in the matriculate exams in each class. In 2020, Dr. Farid established the ScienceAbroad center at MIT, aiming to strengthen the connections between Israeli researchers in the institute and the state of Israel. Moreover, he serves as a volunteer in the American Technion Society. Honors and awards Personal life Farid is married to Michal. Interviews and articles References External links |
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Contents Portable computer A portable computer is a computer designed to be easily moved from one place to another, as opposed to those designed to remain stationary at a single location such as desktops and workstations. These computers usually include a display and keyboard that are directly connected to the main case, all sharing a single power plug together, much like later desktop computers called all-in-ones (AIO) that integrate the system's internal components into the same case as the display. In modern usage, a portable computer usually refers to a very light and compact personal computer such as a laptop, subnotebook or handheld PC, while touchscreen-based handheld ("palmtop") devices such as tablets, phablets and smartphones are called mobile devices instead. The first commercially sold portable computer might be the 20-pound (9.1 kg) MCM/70, released 1974.[citation needed] The next major portables were the 50-pound (23 kg) IBM 5100 (1975), Osborne's 24-pound (11 kg) CP/M-based Osborne 1 (1981) and Compaq's 28-pound (13 kg), advertised as 100% IBM PC compatible Compaq Portable (1983). These luggable computers still required a continuous connection to an external power source; this limitation was later overcome by the laptop computers. Laptops were followed by lighter models such as netbooks, so that in the 2000s mobile devices and by 2007 smartphones made the term "portable" rather meaningless. The 2010s introduced wearable computers such as smartwatches. Portable computers, more narrowly defined, are distinct from desktop replacement computers in that they usually were constructed from full-specification desktop components, and often do not incorporate features associated with laptops or mobile devices. A portable computer in this usage, versus a laptop or other mobile computing device, have a standard motherboard or backplane providing plug-in slots for add-in cards. This allows mission specific cards such as test, A/D, or communication protocol (IEEE-488, 1553) to be installed. Portable computers also provide for more disk storage by using standard disk drives and provide for multiple drives. Early history In 1973, the IBM Los Gatos Scientific Center developed a portable computer prototype called SCAMP (Special Computer APL Machine Portable) based on the IBM PALM processor with a Philips compact cassette drive, small CRT and full function keyboard. SCAMP emulated an IBM 1130 minicomputer in order to run APL\1130. In 1973, APL was generally available only on mainframe computers, and most desktop sized microcomputers such as the Wang 2200 or HP 9800 offered only BASIC. Because SCAMP was the first to emulate APL\1130 performance on a portable, single user computer, PC Magazine in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer". The engineering prototype is in the Smithsonian Institution. Xerox NoteTaker, developed in 1976 at Xerox PARC, was a precursor to later portable computers from Osborne Computer Corporation and Compaq, though it remained a prototype and did not enter production. Successful demonstrations of the 1973 SCAMP prototype led to the first commercial IBM 5100 portable microcomputer launched in 1975. The product incorporated an IBM PALM processor, 5-inch (130 mm) CRT, full function keyboard and the ability to be programmed in both APL and BASIC for engineers, analysts, statisticians and other business problem-solvers. (IBM provided different models of the 5100 supporting only BASIC, only APL, or both selectable by a physical switch on the front panel.) IBM referred to its PALM processor as a microprocessor, though they used that term to mean a processor that executes microcode to implement a higher-level instruction set, rather than its conventional definition of a complete processor on a single silicon integrated circuit; the PALM processor was a large circuit board populated with over a dozen chips. In the late 1960s, such a machine would have been nearly as large as two desks and would have weighed about half a ton (0.45 t). In comparison, the IBM 5100 weighed about 53 pounds (24 kg and very portable for that time). The MIT Suitcase Computer, constructed in 1975, was the first known microprocessor-based portable computer. It was based on the Motorola 6800. Constructed in a Samsonite suitcase approximately 20 by 30 by 8 inches (510 mm × 760 mm × 200 mm) and weighing approximately 20 lb (9.1 kg), it had 4K of SRAM, a serial port to accept downloaded software and connect to a modem, a keyboard and a 40-column thermal printer taken from a cash register. Built by student David Emberson in the MIT Digital Systems Laboratory as a thesis project, it never entered production. It is currently in the collection of Dr. Hoo-Min D. Toong.[citation needed] An early portable computer was manufactured in 1979 by GM Research, a small company in Santa Monica, California. The machine which was designed and patented by James Murez. It was called the Micro Star and later the name was changed to The Small One. Although Xerox claims to have designed the first such system, the machine by Murez predated anything on the market or that had been documented in any publication at the time – hence the patent was issued. As early as 1979, the U.S. Government was contracting to purchase these machines. Other major customers included Sandia Labs, General Dynamics, BBN (featured on the cover of their annual report in 1980 as the C.A.T. system) and several dozen private individuals and companies around the world. In 1979, Adam Osborne viewed the machine along with several hundred other visitors at the first computer show that was sponsored by the IEEE Westec in Los Angeles. Later that year the machine was also shown at the first COMDEX show. The portable micro computer; the "Portal" of the French company R2E Micral CCMC officially appeared in September 1980 at the Sicob show in Paris. The Portal was a portable microcomputer designed and marketed by the studies and developments department of the French firm R2E Micral in 1980 at the request of the company CCMC specializing in payroll and accounting. The Portal was based on an intel 8085 processor, 8-bit, clocked at 2 MHz. It was equipped with a central 64 KB RAM, a keyboard with 58 alpha numeric keys and 11 numeric keys (separate blocks), a 32-character screen, a floppy disk: capacity = 140 000 characters, of a thermal printer: speed = 28 characters / sec, an asynchronous channel, a synchronous channel, a 220 V power supply. Designed for an operating temperature of 15–35 °C (59–95 °F), it weighed 12 kilograms (26 lb) and its dimensions were 45 cm × 45 cm × 15 cm (17.7 in × 17.7 in × 5.9 in). It provided total mobility. Its operating system was Prolog. A few hundred were sold between 1980 and 1983. The first mass-produced microprocessor-based portable computer released in 1981 was the Osborne 1, developed by Osborne, which owed much to the NoteTaker's design. The company had early success with the design and went public but later due to small screen sizes and other devices being released found trouble selling the Osborne. The Osborne 1 is about the size and weight of a sewing machine, and was advertised as the only computer that would fit underneath an airline seat. Another early portable computer released in 1982 was named the Kaypro II, although it was the company's first commercially available product. Some of the press mocked its design—one magazine described Kaypro Corporation as "producing computers packaged in tin cans". Others raved about its value, as the company advertised the Kaypro II as "the $1,595 computer that sells for $1,595", some noting that the included software bundle had a retail value over $1,000 by itself, and by mid-1983 the company was selling more than 10,000 units a month, briefly making it the fifth-largest computer maker in the world. It managed to correct most of the Osborne 1's deficiencies: the screen was larger and showed more characters at once, the floppy drives stored over twice as much data, the case was more attractive-looking, and it was also much better-built and more reliable. The Grid Compass ran its own operating system, GRiD-OS. Its specialized software and high price (US$8,000–10,000) meant that it was limited to specialized applications. The main buyer was the U.S. government. NASA used it on the Space Shuttle during the early 1980s, as it was powerful, lightweight, and compact. The military Special Forces also purchased the machine, as it could be used by paratroopers in combat. Post-IBM PC portables Although Columbia Data Products' MPC 1600, "Multi Personal Computer" came out in the summer of 1982, one of the first extensively IBM PC compatible computers was the Compaq Portable. Eagle Computer then came out with their offering. and Corona Data Systems's PPC-400., the "portable" Hyperion Computer System. Both Eagle Computer and Columbia were sued by IBM for copyright infringement of its BIOS. They settled and were forced to halt production. Neither the Columbia nor the Eagle were nearly as IBM PC DOS compatible as Compaq's offerings. The first full-color portable computer was the Commodore SX-64 in January 1984. Originally announced in 1987, the Atari STacy was released to the public in December 1989 and was one of the first laptop-like portables. Apple Inc. introduced and released the Macintosh Portable in 1989, though this device came with a battery, which added to its substantial weight. The Portable has features similar to the Atari STacy, include integrated trackball and clamshell case. After release of IBM PC Convertible in 1986, IBM still produced classic portable computers, include released in 1989 PS/2 P70 (with upgrade in 1990 to P75), and IBM produce portables for up to release of PS/2 Note and PS/55note notebook lines. Modern portables Freelance journalist David Kline wrote in 1983 that portable computers like his Osborne 1 had "radically transformed my work [and] begun to radically reshape the entire field of journalism", but predicted that such luggables ("Like Neanderthal man ... a species without a future") would be replaced by laptops. Corey Sandler of PC agreed, stating in his review of the Compaq Portable "I will reserve awarding a certificate of full mobility to any computer until it fits in my briefcase". In today's world of laptops, smart phones, and tablets, portable computers have evolved and are now mostly used for industrial, commercial or military applications. Timeline Clock speed is unknown but ADD instructions are documented as taking 16μs, i.e. ~62k ADD/s. See also References External links |
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Contents Orion (constellation) Orion is a prominent set of stars visible during winter in the northern celestial hemisphere. It is one of the 88 modern constellations; it was among the 48 constellations listed by the 2nd-century AD/CE astronomer Ptolemy. It is named after a hunter in Greek mythology. Orion is most prominent during winter evenings in the Northern Hemisphere, as are five other constellations that have stars in the Winter Hexagon asterism. Orion's two brightest stars, Rigel (β) and Betelgeuse (α), are both among the brightest stars in the night sky; both are supergiants and slightly variable. There are a further six stars brighter than magnitude 3.0, including three making the short straight line of the Orion's Belt asterism. Orion also hosts the radiant of the annual Orionids, the strongest meteor shower associated with Halley's Comet, and the Orion Nebula, one of the brightest nebulae in the sky. Characteristics Orion is bordered by Taurus to the northwest, Eridanus to the southwest, Lepus to the south, Monoceros to the east, and Gemini to the northeast. Covering 594 square degrees, Orion ranks 26th of the 88 constellations in size. The constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 26 sides. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 04h 43.3m and 06h 25.5m , while the declination coordinates are between 22.87° and −10.97°. The constellation's three-letter abbreviation, as adopted by the International Astronomical Union in 1922, is "Ori". Orion is most visible in the evening sky from January to April, winter in the Northern Hemisphere, and summer in the Southern Hemisphere. In the tropics (less than about 8° from the equator), the constellation transits at the zenith. From May to July (summer in the Northern Hemisphere, winter in the Southern Hemisphere), Orion is in the daytime sky and thus invisible at most latitudes. However, for much of Antarctica in the Southern Hemisphere's winter months, the Sun is below the horizon even at midday. Stars (and thus Orion, but only the brightest stars) are then visible at twilight for a few hours around local noon, just in the brightest section of the sky low in the North where the Sun is just below the horizon. At the same time of day at the South Pole itself (Amundsen–Scott South Pole Station), Rigel is only 8° above the horizon, and the Belt sweeps just along it. In the Southern Hemisphere's summer months, when Orion is normally visible in the night sky, the constellation is actually not visible in Antarctica because the Sun does not set at that time of year south of the Antarctic Circle. In countries close to the equator (e.g. Kenya, Indonesia, Colombia, Ecuador), Orion appears overhead in December around midnight and in the February evening sky. Navigational aid Orion is very useful as an aid to locating other stars. By extending the line of the Belt southeastward, Sirius (α CMa) can be found; northwestward, Aldebaran (α Tau). A line eastward across the two shoulders indicates the direction of Procyon (α CMi). A line from Rigel through Betelgeuse points to Castor and Pollux (α Gem and β Gem). Additionally, Rigel is part of the Winter Circle asterism. Sirius and Procyon, which may be located from Orion by following imaginary lines (see map), also are points in both the Winter Triangle and the Circle. Features Orion's seven brightest stars form a distinctive hourglass-shaped asterism, or pattern, in the night sky. Four stars—Rigel, Betelgeuse, Bellatrix, and Saiph—form a large roughly rectangular shape, at the center of which lie the three stars of Orion's Belt—Alnitak, Alnilam, and Mintaka. His head is marked by an additional eighth star called Meissa, which is fairly bright to the observer. Descending from the Belt is a smaller line of three stars, Orion's Sword (the middle of which is in fact not a star but the Orion Nebula), also known as the hunter's sword. Many of the stars are luminous hot blue supergiants, with the stars of the Belt and Sword forming the Orion OB1 association. Standing out by its red hue, Betelgeuse may nevertheless be a runaway member of the same group. Orion's Belt, or The Belt of Orion, is an asterism within the constellation. It consists of three bright stars: Alnitak (Zeta Orionis), Alnilam (Epsilon Orionis), and Mintaka (Delta Orionis). Alnitak is around 800 light-years away from Earth, 100,000 times more luminous than the Sun, and shines with a magnitude of 1.8; much of its radiation is in the ultraviolet range, which the human eye cannot see. Alnilam is approximately 2,000 light-years from Earth, shines with a magnitude of 1.70, and with an ultraviolet light that is 375,000 times more luminous than the Sun. Mintaka is 915 light-years away and shines with a magnitude of 2.21. It is 90,000 times more luminous than the Sun and is a double star: the two orbit each other every 5.73 days. In the Northern Hemisphere, Orion's Belt is best visible in the night sky during the month of January at around 9:00 pm, when it is approximately around the local meridian. Just southwest of Alnitak lies Sigma Orionis, a multiple star system composed of five stars that have a combined apparent magnitude of 3.7 and lying at a distance of 1150 light-years. Southwest of Mintaka lies the quadruple star Eta Orionis. Orion's Sword contains the Orion Nebula, the Messier 43 nebula, Sh 2-279 (also known as the Running Man Nebula), and the stars Theta Orionis, Iota Orionis, and 42 Orionis. Three stars comprise a small triangle that marks the head. The apex is marked by Meissa (Lambda Orionis), a hot blue giant of spectral type O8 III and apparent magnitude 3.54, which lies some 1100 light-years distant. Phi-1 and Phi-2 Orionis make up the base. Also nearby is the young star FU Orionis. Stretching north from Betelgeuse are the stars that make up Orion's club. Mu Orionis marks the elbow, Nu and Xi mark the handle of the club, and Chi1 and Chi2 mark the end of the club. Just east of Chi1 is the Mira-type variable red giant star U Orionis. West from Bellatrix lie six stars all designated Pi Orionis (π1 Ori, π2 Ori, π3 Ori, π4 Ori, π5 Ori, and π6 Ori) which make up Orion's shield. Around 20 October each year, the Orionid meteor shower (Orionids) reaches its peak. Coming from the border with the constellation Gemini, as many as 20 meteors per hour can be seen. The shower's parent body is Halley's Comet. Hanging from Orion's Belt is his sword, consisting of the multiple stars θ1 and θ2 Orionis, called the Trapezium and the Orion Nebula (M42). This is a spectacular object that can be clearly identified with the naked eye as something other than a star. Using binoculars, its clouds of nascent stars, luminous gas, and dust can be observed. The Trapezium cluster has many newborn stars, including several brown dwarfs, all of which are at an approximate distance of 1,500 light-years. Named for the four bright stars that form a trapezoid, it is largely illuminated by the brightest stars, which are only a few hundred thousand years old. Observations by the Chandra X-ray Observatory show both the extreme temperatures of the main stars—up to 60,000 kelvins—and the star forming regions still extant in the surrounding nebula. M78 (NGC 2068) is a nebula in Orion. With an overall magnitude of 8.0, it is significantly dimmer than the Great Orion Nebula that lies to its south; however, it is at approximately the same distance, at 1600 light-years from Earth. It can easily be mistaken for a comet in the eyepiece of a telescope. M78 is associated with the variable star V351 Orionis, whose magnitude changes are visible in very short periods of time. Another fairly bright nebula in Orion is NGC 1999, also close to the Great Orion Nebula. It has an integrated magnitude of 10.5 and is 1500 light-years from Earth. The variable star V380 Orionis is embedded in NGC 1999. Another famous nebula is IC 434, the Horsehead Nebula, near Alnitak (Zeta Orionis). It contains a dark dust cloud whose shape gives the nebula its name. NGC 2174 is an emission nebula located 6400 light-years from Earth. Besides these nebulae, surveying Orion with a small telescope will reveal a wealth of interesting deep-sky objects, including M43, M78, and multiple stars including Iota Orionis and Sigma Orionis. A larger telescope may reveal objects such as the Flame Nebula (NGC 2024), as well as fainter and tighter multiple stars and nebulae. Barnard's Loop can be seen on very dark nights or using long-exposure photography. All of these nebulae are part of the larger Orion molecular cloud complex, which is located approximately 1,500 light-years away and is hundreds of light-years across. Due to its proximity, it is one of the most intense regions of stellar formation visible from Earth. The Orion molecular cloud complex forms the eastern part of an even larger structure, the Orion–Eridanus Superbubble, which is visible in X-rays and in hydrogen emissions. History and mythology The distinctive pattern of Orion is recognized in numerous cultures around the world, and many myths are associated with it. Orion is used as a symbol in the modern world. In Siberia, the Chukchi people see Orion as a hunter; an arrow he has shot is represented by Aldebaran (Alpha Tauri), with the same figure as other Western depictions. In Greek mythology, Orion was a gigantic, supernaturally strong hunter, born to Euryale, a Gorgon, and Poseidon (Neptune), god of the sea. One myth recounts Gaia's rage at Orion, who dared to say that he would kill every animal on Earth. The angry goddess tried to dispatch Orion with a scorpion. This is given as the reason that the constellations of Scorpius and Orion are never in the sky at the same time. However, Ophiuchus, the Serpent Bearer, revived Orion with an antidote. This is said to be the reason that the constellation of Ophiuchus stands midway between the Scorpion and the Hunter in the sky. The constellation is mentioned in Horace's Odes (Ode 3.27.18), Homer's Odyssey (Book 5, line 283) and Iliad, and Virgil's Aeneid (Book 1, line 535). In old Hungarian tradition, Orion is known as "Archer" (Íjász), or "Reaper" (Kaszás). In recently rediscovered myths, he is called Nimrod (Hungarian: Nimród), the greatest hunter, father of the twins Hunor and Magor. The π and o stars (on upper right) form together the reflex bow or the lifted scythe. In other Hungarian traditions, Orion's Belt is known as "Judge's stick" (Bírópálca). In Ireland and Scotland, Orion was called An Bodach, a figure from Irish folklore whose name literally means "the one with a penis [bod]" and was the husband of the Cailleach (hag). In Scandinavian tradition, Orion's Belt was known as "Frigg's Distaff" (friggerock) or "Freyja's distaff". The Finns call Orion's Belt and the stars below it "Väinämöinen's scythe" (Väinämöisen viikate). Another name for the asterism of Alnilam, Alnitak, and Mintaka is "Väinämöinen's Belt" (Väinämöisen vyö) and the stars "hanging" from the Belt as "Kaleva's sword" (Kalevanmiekka). There are claims in popular media that the Adorant from the Geißenklösterle cave, an ivory carving estimated to be 35,000 to 40,000 years old, is the first known depiction of the constellation. Scholars dismiss such interpretations, saying that perceived details such as a belt and sword derive from preexisting features in the grain structure of the ivory. The Babylonian star catalogues of the Late Bronze Age name Orion MULSIPA.ZI.AN.NA,[note 1] "The Heavenly Shepherd" or "True Shepherd of Anu" – Anu being the chief god of the heavenly realms. The Babylonian constellation is sacred to Papshukal and Ninshubur, both minor gods fulfilling the role of "messenger to the gods". Papshukal is closely associated with the figure of a walking bird on Babylonian boundary stones, and on the star map the figure of the Rooster is located below and behind the figure of the True Shepherd—both constellations represent the herald of the gods, in his bird and human forms respectively. In ancient Egypt, the stars of Orion were regarded as a god, called Sah. Because Orion rises before Sirius, the star whose heliacal rising was the basis for the Solar Egyptian calendar, Sah was closely linked with Sopdet, the goddess who personified Sirius. The god Sopdu is said to be the son of Sah and Sopdet. Sah is syncretized with Osiris, while Sopdet is syncretized with Osiris' mythological wife, Isis. In the Pyramid Texts, from the 24th and 23rd centuries BC, Sah is one of many gods whose form the dead pharaoh is said to take in the afterlife. The Armenians identified their legendary patriarch and founder Hayk with Orion. Hayk is also the name of the Orion constellation in the Armenian translation of the Bible. The Bible mentions Orion three times, naming it "Kesil" (כסיל, literally – fool). Though, this name perhaps is etymologically connected with "Kislev", the name for the ninth month of the Hebrew calendar (i.e. November–December), which, in turn, may derive from the Hebrew root K-S-L as in the words "kesel, kisla" (כֵּסֶל, כִּסְלָה, hope, positiveness), i.e. hope for winter rains.: Job 9:9 ("He is the maker of the Bear and Orion"), Job 38:31 ("Can you loosen Orion's belt?"), and Amos 5:8 ("He who made the Pleiades and Orion"). In ancient Aram, the constellation was known as Nephîlā′, the Nephilim are said to be Orion's descendants. In medieval Muslim astronomy, Orion was known as al-jabbar, "the giant". Orion's sixth brightest star, Saiph, is named from the Arabic, saif al-jabbar, meaning "sword of the giant". In China, Orion was one of the 28 lunar mansions Sieu (Xiù) (宿). It is known as Shen (參), literally meaning "three", for the stars of Orion's Belt. The Chinese character 參 (pinyin shēn) originally meant the constellation Orion (Chinese: 參宿; pinyin: shēnxiù); its Shang dynasty version, over three millennia old, contains at the top a representation of the three stars of Orion's Belt atop a man's head (the bottom portion representing the sound of the word was added later). The Rigveda refers to the constellation as Mriga (the Deer). Nataraja, "the cosmic dancer", is often interpreted as the representation of Orion. Rudra, the Rigvedic form of Shiva, is the presiding deity of Ardra nakshatra (Betelgeuse) of Hindu astrology. The Jain Symbol carved in the Udayagiri and Khandagiri Caves, India in 1st century BCE has a striking resemblance with Orion. Bugis sailors identified the three stars in Orion's Belt as tanra tellué, meaning "sign of three". The Seri people of northwestern Mexico call the three stars in Orion's Belt Hapj (a name denoting a hunter) which consists of three stars: Hap (mule deer), Haamoja (pronghorn), and Mojet (bighorn sheep). Hap is in the middle and has been shot by the hunter; its blood has dripped onto Tiburón Island. The same three stars are known in Spain and most of Latin America as "Las tres Marías" (Spanish for "The Three Marys"). In Puerto Rico, the three stars are known as the "Los Tres Reyes Magos" (Spanish for The Three Wise Men). The Ojibwa/Chippewa Native Americans call this constellation Mesabi for Big Man. To the Lakota Native Americans, Tayamnicankhu (Orion's Belt) is the spine of a bison. The great rectangle of Orion is the bison's ribs; the Pleiades star cluster in nearby Taurus is the bison's head; and Sirius in Canis Major, known as Tayamnisinte, is its tail. Another Lakota myth mentions that the bottom half of Orion, the Constellation of the Hand, represented the arm of a chief that was ripped off by the Thunder People as a punishment from the gods for his selfishness. His daughter offered to marry the person who can retrieve his arm from the sky, so the young warrior Fallen Star (whose father was a star and whose mother was human) returned his arm and married his daughter, symbolizing harmony between the gods and humanity with the help of the younger generation. The index finger is represented by Rigel; the Orion Nebula is the thumb; the Belt of Orion is the wrist; and the star Beta Eridani is the pinky finger. The seven primary stars of Orion make up the Polynesian constellation Heiheionakeiki which represents a child's string figure similar to a cat's cradle. Several precolonial Filipinos referred to the belt region in particular as "balatik" (ballista) as it resembles a trap of the same name which fires arrows by itself and is usually used for catching pigs from the bush. Spanish colonization later led to some ethnic groups referring to Orion's Belt as "Tres Marias" or "Tatlong Maria." In Māori tradition, the star Rigel (known as Puanga or Puaka) is closely connected with the celebration of Matariki. The rising of Matariki (the Pleiades) and Rigel before sunrise in midwinter marks the start of the Māori year. In Javanese culture, the constellation is often called Lintang Waluku or Bintang Bajak, referring to the shape of a paddy field plow. The imagery of the Belt and Sword has found its way into popular Western culture, for example in the form of the shoulder insignia of the 27th Infantry Division of the United States Army during both World Wars, probably owing to a pun on the name of the division's first commander, Major General John F. O'Ryan. The film distribution company Orion Pictures used the constellation as its logo. In artistic renderings, the surrounding constellations are sometimes related to Orion: he is depicted standing next to the river Eridanus with his two hunting dogs Canis Major and Canis Minor, fighting Taurus. He is sometimes depicted hunting Lepus the hare. He sometimes is depicted to have a lion's hide in his hand. There are alternative ways to visualise Orion. From the Southern Hemisphere, Orion is oriented south-upward, and the Belt and Sword are sometimes called the saucepan or pot in Australia and New Zealand. Orion's Belt is called Drie Konings (Three Kings) or the Drie Susters (Three Sisters) by Afrikaans speakers in South Africa and are referred to as les Trois Rois (the Three Kings) in Daudet's Lettres de Mon Moulin (1866). The appellation Driekoningen (the Three Kings) is also often found in 17th and 18th-century Dutch star charts and seaman's guides. The same three stars are known in Spain, Latin America, and the Philippines as "Las Tres Marías" (The Three Marys), and as "Los Tres Reyes Magos" (The Three Wise Men) in Puerto Rico. Even traditional depictions of Orion have varied greatly. Cicero drew Orion in a similar fashion to the modern depiction. The Hunter held an unidentified animal skin aloft in his right hand; his hand was represented by Omicron2 Orionis and the skin was represented by the five stars designated Pi Orionis. Saiph and Rigel represented his left and right knees, while Eta Orionis and Lambda Leporis were his left and right feet, respectively. As in the modern depiction, Mintaka, Alnilam, and Alnitak represented his Belt. His left shoulder was represented by Betelgeuse, and Mu Orionis made up his left arm. Meissa was his head, and Bellatrix his right shoulder. The depiction of Hyginus was similar to that of Cicero, though the two differed in a few important areas. Cicero's animal skin became Hyginus's shield (Omicron and Pi Orionis), and instead of an arm marked out by Mu Orionis, he holds a club (Chi Orionis). His right leg is represented by Theta Orionis and his left leg is represented by Lambda, Mu, and Epsilon Leporis. Further Western European and Arabic depictions have followed these two models. Future Orion is located on the celestial equator, but it will not always be so located due to the effects of precession of the Earth's axis. Orion lies well south of the ecliptic, and it only happens to lie on the celestial equator because the point on the ecliptic that corresponds to the June solstice is close to the border of Gemini and Taurus, to the north of Orion. Precession will eventually carry Orion further south, and by AD 14000, Orion will be far enough south that it will no longer be visible from the latitude of Great Britain. Further in the future, Orion's stars will gradually move away from the constellation due to proper motion. However, Orion's brightest stars all lie at a large distance from Earth on an astronomical scale—much farther away than Sirius, for example. Orion will still be recognizable long after most of the other constellations—composed of relatively nearby stars—have distorted into new configurations, with the exception of a few of its stars eventually exploding as supernovae, for example Betelgeuse, which is predicted to explode sometime in the next million years. See also References External links |
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[SOURCE: https://en.wikipedia.org/wiki/Talk:Weak_artificial_intelligence] | [TOKENS: 1589] |
Contents Talk:Weak artificial intelligence Narrow != Weak Narrow AI may well be what is defined in the article, but the weak/strong AI distinction is VERY different. See https://en.wikipedia.org/wiki/Chinese_room#Strong_AI ALso Ray Kurzeuil and all the sigularity thing is interesting and entertaining, but is NOT reality, but speculation. With respect, I call for a return to the version before 149.254.58.203's edits. DISCUSS. Samfreed (talk) 14:51, 23 October 2014 (UTC)[reply] Altho speculative now, the future is a real thing and it's coming here soon. I suggest that where the first sentence says: real-world, I've just made lots of edits to improve the article. Here are some links I didn't use: — Preceding unsigned comment added by 149.254.181.50 (talk) 21:42, 17 February 2014 (UTC)[reply] — Preceding unsigned comment added by 149.254.58.203 (talk) 17:19, 16 February 2014 (UTC)[reply] Possible confusion with weak methods in AI The article should mention that this has nothing to do with the concept of using 'weak methods' in AI. This was made popular Newell in the the late 1960s (Newell, A. Heuristic programming: Ill-structured problems. In Aronofsky, J. (Ed.), Progress in Operations Research, III. New York: Wiley, 1969). See also: weak methods 1. problem-solving techniques based on general principles rather than specific, domain-relevant knowledge. Such methods can be applied to a wide variety of problems but may be inefficient in many cases. 2. in artificial intelligence, programs based on general principles that do not take into account knowledge specific to any particular application or domain. Compare strong methods. — Preceding unsigned comment added by Finin (talk • contribs) 14:26, 7 February 2019 (UTC)[reply] Seeking to improve I would like to improve this article, and here is what I plan to do: I will add more reliable sources including ones from the UC Berkeley library. I also plan on explaining more about the differences between narrow and weak AI. Furthermore, I will talk about how weak AI exists in the real world today, and how it can be an issue to our current society. This article does not have an picture with a caption on the right side, so if I can figure out how to do that, I would also like to add one. Here and at the bottom of the page are the sources I plan on using: References Peer Review I think this is a really good start, especially considering that you are drafting a brand new article. I really like the specific, well-divided sections along with the table of contents. Furthermore, your sources look reliable (maybe add a few more if you can?). Although weak artificial intelligence may be a part of civic tech itself, there is still somewhat a lack of a connection between weak and/or strong ai with civic tech. Also, you could really expand on the "impact" section as that is really what the heart of the article could be. Other than that which you probably already had in mind to add on, looks good. Lavarball13 (talk) 03:29, 18 October 2022 (UTC)[reply] Wiki Education assignment: Civic Technology This article was the subject of a Wiki Education Foundation-supported course assignment, between 24 August 2022 and 30 November 2022. Further details are available on the course page. Student editor(s): SkyradBear (article contribs). — Assignment last updated by SkyradBear (talk) 21:56, 24 October 2022 (UTC)[reply] Confusing terminology Here a few technical aspects of the article that I think could be improved: 1) I find the definition of weak AI ("artificial intelligence that implements a limited part of mind") a bit unclear and controversial. The defining criterion in Searle's definition of weak AI seems to be that it is not conscious (Searle ambiguously uses the word "understanding" but only to refer to the feeling of understanding, cf. Chinese Room#Consciousness). Searle's definition of weak AI is independent of AI capabilities (it is epiphenomenal), whereas the definition of narrow AI is all about capabilities. 2) Since not everyone follows Searle's terminology, the term weak AI is ambiguous and is sometimes used interchangeably with narrow AI. Most of the time, this article ignores Searle's terminology and uses "weak AI" as a synonym of "narrow AI" and "strong AI" as a synonym of "artificial general intelligence". I propose using the more precise terminology instead: "narrow AI" and "artificial general intelligence". (I think the concept of weak AI is ill-defined and the article should have focused more on narrow AI which has a clear and useful meaning. Maybe we could consider also changing the title?) 3) This sentence looks inaccurate to me : "Weak artificial intelligence focuses on mimicking how humans perform basic actions such as remembering things, perceiving things, and solving simple problems." Narrow or weak AIs don't necessarily mimick human data (e.g. game-playing AIs are usually trained only with reinforcement learning, without human data). This sentence looks a bit inaccurate too : "Weak AI is not able to have a mind of its own, and can only imitate physical behaviors that it can observe." 4) As far as I know, assistants like Siri are not so narrow anymore. I'm also not sure that "robots" or "diagnostic doctors" are a good example anymore, because they are now usually getting some advanced language processing abilities. I think a better example of a narrow AI would be game-playing AIs, like AlphaGo, which can only play Go. AI classifiers or anomaly detection algorithms are also good examples. 5) This part is a bit weird : "The reason all of these are weak AI systems, self-driving cars can cause deadly accidents similarly to how humans normally can." I propose replacing it with something like: "Narrow AI systems are sometimes dangerous if unreliable." What do you think? Thanks for the feedback. Alenoach (talk) 19:55, 29 October 2023 (UTC)[reply] New image I doubt the recently added image is encyclopedic enough. It appears to be generic art. WeyerStudentOfAgrippa (talk) 01:16, 25 May 2024 (UTC)[reply] Requested move 2 October 2024 The result of the move request was: no consensus. (non-admin closure) Alpha3031 (t • c) 20:42, 22 October 2024 (UTC)[reply] Weak artificial intelligence → Narrow artificial intelligenceNarrow artificial intelligence – the term "Weak artificial intelligence" is ambiguous and confusing, contrary to the term "Narrow artificial intelligence", which is basically AI designed for a narrow range of tasks. This is also most of what the article is about, although we could keep a section covering the term "Weak AI". The title "Narrow AI" can also be considered. Alenoach (talk) 00:43, 2 October 2024 (UTC) — Relisting. Raladic (talk) 01:37, 9 October 2024 (UTC) — Relisting. Safari ScribeEdits! Talk! 05:55, 16 October 2024 (UTC)[reply] |
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[SOURCE: https://en.wikipedia.org/wiki/Middle_East#cite_note-ArchMag-40] | [TOKENS: 6152] |
Contents Middle East The Middle East[b] is a geopolitical region encompassing the Arabian Peninsula, Egypt, Iran, Iraq, the Levant, and Turkey. The term came into widespread usage by Western European nations in the early 20th century as a replacement of the term Near East (both were in contrast to the Far East). The term "Middle East" has led to some confusion over its changing definitions. Since the late 20th century, it has been criticized as being too Eurocentric. The region includes the vast majority of the territories included in the closely associated definition of West Asia, but without the South Caucasus. It also includes all of Egypt (not just the Sinai region) and all of Turkey (including East Thrace). Most Middle Eastern countries (13 out of 18) are part of the Arab world. The three most populous countries in the region are Egypt, Iran, and Turkey, while Saudi Arabia is the largest Middle Eastern country by area. The history of the Middle East dates back to ancient times, and it was long considered the "cradle of civilization". The geopolitical importance of the region has been recognized and competed for during millennia. The Abrahamic religions (Judaism, Christianity, and Islam) have their origins in the Middle East. Arabs constitute the main ethnic group in the region, followed by Turks, Persians, Kurds, Jews, and Assyrians. The Middle East generally has a hot, arid climate, especially in the Arabian and Egyptian regions. Several major rivers provide irrigation to support agriculture in limited areas here, such as the Nile Delta in Egypt, the Tigris and Euphrates watersheds of Mesopotamia, and the basin of the Jordan River that spans most of the Levant. These regions are collectively known as the Fertile Crescent, and comprise the core of what historians had long referred to as the cradle of civilization; multiple regions of the world have since been classified as also having developed independent, original civilizations. Conversely, the Levantine coast and most of Turkey have relatively temperate climates typical of the Mediterranean, with dry summers and cool, wet winters. Most of the countries that border the Persian Gulf have vast reserves of petroleum. Monarchs of the Arabian Peninsula in particular have benefitted economically from petroleum exports. Because of the arid climate and dependence on the fossil fuel industry, the Middle East is both a major contributor to climate change and a region that is expected to be severely adversely affected by it. Other concepts of the region exist, including the broader Middle East and North Africa (MENA), which includes states of the Maghreb and the Sudan. The term the "Greater Middle East" also includes Afghanistan, Mauritania, Pakistan, as well as parts of East Africa, and sometimes Central Asia and the South Caucasus. Terminology The term "Middle East" may have originated in the 1850s in the British India Office. However, it became more widely known when United States naval strategist Alfred Thayer Mahan used the term in 1902 to "designate the area between Arabia and India". During this time the British and Russian empires were vying for influence in Central Asia, a rivalry that would become known as the Great Game. Mahan realized not only the strategic importance of the region, but also of its center, the Persian Gulf. He labeled the area surrounding the Persian Gulf as the Middle East. He said that, beyond Egypt's Suez Canal, the Gulf was the most important passage for Britain to control in order to keep the Russians from advancing towards British India. Mahan first used the term in his article "The Persian Gulf and International Relations", published in September 1902 in the National Review, a British journal. The Middle East, if I may adopt a term which I have not seen, will some day need its Malta, as well as its Gibraltar; it does not follow that either will be in the Persian Gulf. Naval force has the quality of mobility which carries with it the privilege of temporary absences; but it needs to find on every scene of operation established bases of refit, of supply, and in case of disaster, of security. The British Navy should have the facility to concentrate in force if occasion arise, about Aden, India, and the Persian Gulf. Mahan's article was reprinted in The Times and followed in October by a 20-article series entitled "The Middle Eastern Question", written by Sir Ignatius Valentine Chirol. During this series, Sir Ignatius expanded the definition of Middle East to include "those regions of Asia which extend to the borders of India or command the approaches to India." After the series ended in 1903, The Times removed quotation marks from subsequent uses of the term. Until World War II, it was customary to refer to areas centered on Turkey and the eastern shore of the Mediterranean as the "Near East", while the "Far East" centered on China, India and Japan. The Middle East was then defined as the area from Mesopotamia to Burma; namely, the area between the Near East and the Far East. This area broadly corresponds to South Asia. In the late 1930s, the British established the Middle East Command, which was based in Cairo, for its military forces in the region. After that time, the term "Middle East" gained broader usage in Europe and the United States. Following World War II, for example, the Middle East Institute was founded in Washington, D.C. in 1946. The corresponding adjective is Middle Eastern and the derived noun is Middle Easterner. While non-Eurocentric terms such as "Southwest Asia" or "Swasia" have been sparsely used, the classification of the African country, Egypt, among those counted in the Middle East challenges the usefulness of using such terms. The description Middle has also led to some confusion over changing definitions. Before the First World War, "Near East" was used in English to refer to the Balkans and the Ottoman Empire, while "Middle East" referred to the Caucasus, Persia, and Arabian lands, and sometimes Afghanistan, India and others. In contrast, "Far East" referred to the countries of East Asia (e.g. China, Japan, and Korea). With the collapse of the Ottoman Empire in 1918, "Near East" largely fell out of common use in English, while "Middle East" came to be applied to the emerging independent countries of the Islamic world. However, the usage "Near East" was retained by a variety of academic disciplines, including archaeology and ancient history. In their usage, the term describes an area identical to the term Middle East, which is not used by these disciplines (see ancient Near East).[citation needed] The first official use of the term "Middle East" by the United States government was in the 1957 Eisenhower Doctrine, which pertained to the Suez Crisis. Secretary of State John Foster Dulles defined the Middle East as "the area lying between and including Libya on the west and Pakistan on the east, Syria and Iraq on the North and the Arabian peninsula to the south, plus the Sudan and Ethiopia." In 1958, the State Department explained that the terms "Near East" and "Middle East" were interchangeable, and defined the region as including only Egypt, Syria, Israel, Lebanon, Jordan, Iraq, Saudi Arabia, Kuwait, Bahrain, and Qatar. Since the late 20th century, scholars and journalists from the region, such as journalist Louay Khraish and historian Hassan Hanafi have criticized the use of "Middle East" as a Eurocentric and colonialist term. The Associated Press Stylebook of 2004 says that Near East formerly referred to the farther west countries while Middle East referred to the eastern ones, but that now they are synonymous. It instructs: Use Middle East unless Near East is used by a source in a story. Mideast is also acceptable, but Middle East is preferred. European languages have adopted terms similar to Near East and Middle East. Since these are based on a relative description, the meanings depend on the country and are generally different from the English terms. In German the term Naher Osten (Near East) is still in common use (nowadays the term Mittlerer Osten is more and more common in press texts translated from English sources, albeit having a distinct meaning). In the four Slavic languages, Russian Ближний Восток or Blizhniy Vostok, Bulgarian Близкия Изток, Polish Bliski Wschód or Croatian Bliski istok (terms meaning Near East are the only appropriate ones for the region). However, some European languages do have "Middle East" equivalents, such as French Moyen-Orient, Swedish Mellanöstern, Spanish Oriente Medio or Medio Oriente, Greek is Μέση Ανατολή (Mesi Anatoli), and Italian Medio Oriente.[c] Perhaps because of the political influence of the United States and Europe, and the prominence of Western press, the Arabic equivalent of Middle East (Arabic: الشرق الأوسط ash-Sharq al-Awsaṭ) has become standard usage in the mainstream Arabic press. It comprises the same meaning as the term "Middle East" in North American and Western European usage. The designation, Mashriq, also from the Arabic root for East, also denotes a variously defined region around the Levant, the eastern part of the Arabic-speaking world (as opposed to the Maghreb, the western part). Even though the term originated in the West, countries of the Middle East that use languages other than Arabic also use that term in translation. For instance, the Persian equivalent for Middle East is خاورمیانه (Khāvar-e miyāneh), the Hebrew is המזרח התיכון (hamizrach hatikhon), and the Turkish is Orta Doğu. Countries and territory Traditionally included within the Middle East are Arabia, Asia Minor, East Thrace, Egypt, Iran, the Levant, Mesopotamia, and the Socotra Archipelago. The region includes 17 UN-recognized countries and one British Overseas Territory. Various concepts are often paralleled to the Middle East, most notably the Near East, Fertile Crescent, and Levant. These are geographical concepts, which refer to large sections of the modern-day Middle East, with the Near East being the closest to the Middle East in its geographical meaning. Due to it primarily being Arabic speaking, the Maghreb region of North Africa is sometimes included. "Greater Middle East" is a political term coined by the second Bush administration in the first decade of the 21st century to denote various countries, pertaining to the Muslim world, specifically Afghanistan, Iran, Pakistan, and Turkey. Various Central Asian countries are sometimes also included. History The Middle East lies at the juncture of Africa and Eurasia and of the Indian Ocean and the Mediterranean Sea (see also: Indo-Mediterranean). It is the birthplace and spiritual center of religions such as Christianity, Islam, Judaism, Manichaeism, Yezidi, Druze, Yarsan, and Mandeanism, and in Iran, Mithraism, Zoroastrianism, Manicheanism, and the Baháʼí Faith. Throughout its history the Middle East has been a major center of world affairs; a strategically, economically, politically, culturally, and religiously sensitive area. The region is one of the regions where agriculture was independently discovered, and from the Middle East it was spread, during the Neolithic, to different regions of the world such as Europe, the Indus Valley and Eastern Africa. Prior to the formation of civilizations, advanced cultures formed all over the Middle East during the Stone Age. The search for agricultural lands by agriculturalists, and pastoral lands by herdsmen meant different migrations took place within the region and shaped its ethnic and demographic makeup. The Middle East is widely and most famously known as the cradle of civilization. The world's earliest civilizations, Mesopotamia (Sumer, Akkad, Assyria and Babylonia), ancient Egypt and Kish in the Levant, all originated in the Fertile Crescent and Nile Valley regions of the ancient Near East. These were followed by the Hittite, Greek, Hurrian and Urartian civilisations of Asia Minor; Elam, Persia and Median civilizations in Iran, as well as the civilizations of the Levant (such as Ebla, Mari, Nagar, Ugarit, Canaan, Aramea, Mitanni, Phoenicia and Israel) and the Arabian Peninsula (Magan, Sheba, Ubar). The Near East was first largely unified under the Neo Assyrian Empire, then the Achaemenid Empire followed later by the Macedonian Empire and after this to some degree by the Iranian empires (namely the Parthian and Sassanid Empires), the Roman Empire and Byzantine Empire. The region served as the intellectual and economic center of the Roman Empire and played an exceptionally important role due to its periphery on the Sassanid Empire. Thus, the Romans stationed up to five or six of their legions in the region for the sole purpose of defending it from Sassanid and Bedouin raids and invasions. From the 4th century CE onwards, the Middle East became the center of the two main powers at the time, the Byzantine Empire and the Sassanid Empire. However, it would be the later Islamic Caliphates of the Middle Ages, or Islamic Golden Age which began with the Islamic conquest of the region in the 7th century AD, that would first unify the entire Middle East as a distinct region and create the dominant Islamic Arab ethnic identity that largely (but not exclusively) persists today. The 4 caliphates that dominated the Middle East for more than 600 years were the Rashidun Caliphate, the Umayyad caliphate, the Abbasid caliphate and the Fatimid caliphate. Additionally, the Mongols would come to dominate the region, the Kingdom of Armenia would incorporate parts of the region to their domain, the Seljuks would rule the region and spread Turko-Persian culture, and the Franks would found the Crusader states that would stand for roughly two centuries. Josiah Russell estimates the population of what he calls "Islamic territory" as roughly 12.5 million in 1000 – Anatolia 8 million, Syria 2 million, and Egypt 1.5 million. From the 16th century onward, the Middle East came to be dominated, once again, by two main powers: the Ottoman Empire and the Safavid dynasty. The modern Middle East began after World War I, when the Ottoman Empire, which was allied with the Central Powers, was defeated by the Allies and partitioned into a number of separate nations, initially under British and French Mandates. Other defining events in this transformation included the establishment of Israel in 1948 and the eventual departure of European powers, notably Britain and France by the end of the 1960s. They were supplanted in some part by the rising influence of the United States from the 1970s onwards. In the 20th century, the region's significant stocks of crude oil gave it new strategic and economic importance. Mass production of oil began around 1945, with Saudi Arabia, Iran, Kuwait, Iraq, and the United Arab Emirates having large quantities of oil. Estimated oil reserves, especially in Saudi Arabia and Iran, are some of the highest in the world, and the international oil cartel OPEC is dominated by Middle Eastern countries. During the Cold War, the Middle East was a theater of ideological struggle between the two superpowers and their allies: NATO and the United States on one side, and the Soviet Union and Warsaw Pact on the other, as they competed to influence regional allies. Besides the political reasons there was also the "ideological conflict" between the two systems. Moreover, as Louise Fawcett argues, among many important areas of contention, or perhaps more accurately of anxiety, were, first, the desires of the superpowers to gain strategic advantage in the region, second, the fact that the region contained some two-thirds of the world's oil reserves in a context where oil was becoming increasingly vital to the economy of the Western world [...] Within this contextual framework, the United States sought to divert the Arab world from Soviet influence. Throughout the 20th and 21st centuries, the region has experienced both periods of relative peace and tolerance and periods of conflict particularly between Sunnis and Shiites. Geography In 2018, the MENA region emitted 3.2 billion tonnes of carbon dioxide and produced 8.7% of global greenhouse gas emissions (GHG) despite making up only 6% of the global population. These emissions are mostly from the energy sector, an integral component of many Middle Eastern and North African economies due to the extensive oil and natural gas reserves that are found within the region. The Middle East region is one of the most vulnerable to climate change. The impacts include increase in drought conditions, aridity, heatwaves and sea level rise. Sharp global temperature and sea level changes, shifting precipitation patterns and increased frequency of extreme weather events are some of the main impacts of climate change as identified by the Intergovernmental Panel on Climate Change (IPCC). The MENA region is especially vulnerable to such impacts due to its arid and semi-arid environment, facing climatic challenges such as low rainfall, high temperatures and dry soil. The climatic conditions that foster such challenges for MENA are projected by the IPCC to worsen throughout the 21st century. If greenhouse gas emissions are not significantly reduced, part of the MENA region risks becoming uninhabitable before the year 2100. Climate change is expected to put significant strain on already scarce water and agricultural resources within the MENA region, threatening the national security and political stability of all included countries. Over 60 percent of the region's population lives in high and very high water-stressed areas compared to the global average of 35 percent. This has prompted some MENA countries to engage with the issue of climate change on an international level through environmental accords such as the Paris Agreement. Law and policy are also being established on a national level amongst MENA countries, with a focus on the development of renewable energies. Economy Middle Eastern economies range from being very poor (such as Gaza and Yemen) to extremely wealthy nations (such as Qatar and UAE). According to the International Monetary Fund, the three largest Middle Eastern economies in nominal GDP in 2023 were Saudi Arabia ($1.06 trillion), Turkey ($1.03 trillion), and Israel ($0.54 trillion). For nominal GDP per person, the highest ranking countries are Qatar ($83,891), Israel ($55,535), the United Arab Emirates ($49,451) and Cyprus ($33,807). Turkey ($3.6 trillion), Saudi Arabia ($2.3 trillion), and Iran ($1.7 trillion) had the largest economies in terms of GDP PPP. For GDP PPP per person, the highest-ranking countries are Qatar ($124,834), the United Arab Emirates ($88,221), Saudi Arabia ($64,836), Bahrain ($60,596) and Israel ($54,997). The lowest-ranking country in the Middle East, in terms of GDP nominal per capita, is Yemen ($573). The economic structure of Middle Eastern nations are different because while some are heavily dependent on export of only oil and oil-related products (Saudi Arabia, the UAE and Kuwait), others have a highly diverse economic base (such as Cyprus, Israel, Turkey and Egypt). Industries of the Middle Eastern region include oil and oil-related products, agriculture, cotton, cattle, dairy, textiles, leather products, surgical instruments, defence equipment (guns, ammunition, tanks, submarines, fighter jets, UAVs, and missiles). Banking is an important sector, especially for UAE and Bahrain. With the exception of Cyprus, Turkey, Egypt, Lebanon and Israel, tourism has been a relatively undeveloped area of the economy, in part because of the socially conservative nature of the region as well as political turmoil in certain regions. Since the end of the COVID pandemic however, countries such as the UAE, Bahrain, and Jordan have begun attracting greater numbers of tourists because of improving tourist facilities and the relaxing of tourism-related restrictive policies. Unemployment is high in the Middle East and North Africa region, particularly among people aged 15–29, a demographic representing 30% of the region's population. The total regional unemployment rate in 2025 is 10.8%, and among youth is as high as 28%. Demographics Arabs constitute the largest ethnic group in the Middle East, followed by various Iranian peoples and then by Turkic peoples (Turkish, Azeris, Syrian Turkmen, and Iraqi Turkmen). Native ethnic groups of the region include, in addition to Arabs, Arameans, Assyrians, Baloch, Berbers, Copts, Druze, Greek Cypriots, Jews, Kurds, Lurs, Mandaeans, Persians, Samaritans, Shabaks, Tats, and Zazas. European ethnic groups that form a diaspora in the region include Albanians, Bosniaks, Circassians (including Kabardians), Crimean Tatars, Greeks, Franco-Levantines, Italo-Levantines, and Iraqi Turkmens. Among other migrant populations are Chinese, Filipinos, Indians, Indonesians, Pakistanis, Pashtuns, Romani, and Afro-Arabs. "Migration has always provided an important vent for labor market pressures in the Middle East. For the period between the 1970s and 1990s, the Arab states of the Persian Gulf in particular provided a rich source of employment for workers from Egypt, Yemen and the countries of the Levant, while Europe had attracted young workers from North African countries due both to proximity and the legacy of colonial ties between France and the majority of North African states." According to the International Organization for Migration, there are 13 million first-generation migrants from Arab nations in the world, of which 5.8 reside in other Arab countries. Expatriates from Arab countries contribute to the circulation of financial and human capital in the region and thus significantly promote regional development. In 2009 Arab countries received a total of US$35.1 billion in remittance in-flows and remittances sent to Jordan, Egypt and Lebanon from other Arab countries are 40 to 190 per cent higher than trade revenues between these and other Arab countries. In Somalia, the Somali Civil War has greatly increased the size of the Somali diaspora, as many of the best educated Somalis left for Middle Eastern countries as well as Europe and North America. Non-Arab Middle Eastern countries such as Turkey, Israel and Iran are also subject to important migration dynamics. A fair proportion of those migrating from Arab nations are from ethnic and religious minorities facing persecution and are not necessarily ethnic Arabs, Iranians or Turks.[citation needed] Large numbers of Kurds, Jews, Assyrians, Greeks and Armenians as well as many Mandeans have left nations such as Iraq, Iran, Syria and Turkey for these reasons during the last century. In Iran, many religious minorities such as Christians, Baháʼís, Jews and Zoroastrians have left since the Islamic Revolution of 1979. The Middle East is very diverse when it comes to religions, many of which originated there. Islam is the largest religion in the Middle East, but other faiths that originated there, such as Judaism and Christianity, are also well represented. Christian communities have played a vital role in the Middle East, and they represent 78% of Cyprus population, and 40.5% of Lebanon, where the Lebanese president, half of the cabinet, and half of the parliament follow one of the various Lebanese Christian rites. There are also important minority religions like the Baháʼí Faith, Yarsanism, Yazidism, Zoroastrianism, Mandaeism, Druze, and Shabakism, and in ancient times the region was home to Mesopotamian religions, Canaanite religions, Manichaeism, Mithraism and various monotheist gnostic sects. The six top languages, in terms of numbers of speakers, are Arabic, Persian, Turkish, Kurdish, Modern Hebrew and Greek. About 20 minority languages are also spoken in the Middle East. Arabic, with all its dialects, is the most widely spoken language in the Middle East, with Literary Arabic being official in all North African and in most West Asian countries. Arabic dialects are also spoken in some adjacent areas in neighbouring Middle Eastern non-Arab countries. It is a member of the Semitic branch of the Afro-Asiatic languages. Several Modern South Arabian languages such as Mehri and Soqotri are also spoken in Yemen and Oman. Another Semitic language is Aramaic and its dialects are spoken mainly by Assyrians and Mandaeans, with Western Aramaic still spoken in two villages near Damascus, Syria. There is also an Oasis Berber-speaking community in Egypt where the language is also known as Siwa. It is a non-Semitic Afro-Asiatic sister language. Persian is the second most spoken language. While it is primarily spoken in Iran and some border areas in neighbouring countries, the country is one of the region's largest and most populous. It belongs to the Indo-Iranian branch of the family of Indo-European languages. Other Western Iranic languages spoken in the region include Achomi, Daylami, Kurdish dialects, Semmani, Lurish, amongst many others. The close third-most widely spoken language, Turkish, is largely confined to Turkey, which is also one of the region's largest and most populous countries, but it is present in areas in neighboring countries. It is a member of the Turkic languages, which have their origins in East Asia. Another Turkic language, Azerbaijani, is spoken by Azerbaijanis in Iran. The fourth-most widely spoken language, Kurdish, is spoken in the countries of Iran, Iraq, Syria and Turkey, Sorani Kurdish is the second official language in Iraq (instated after the 2005 constitution) after Arabic. Hebrew is the official language of Israel, with Arabic given a special status after the 2018 Basic law lowered its status from an official language prior to 2018. Hebrew is spoken and used by over 80% of Israel's population, the other 20% using Arabic. Modern Hebrew only began being spoken in the 20th century after being revived in the late 19th century by Elizer Ben-Yehuda (Elizer Perlman) and European Jewish settlers, with the first native Hebrew speaker being born in 1882. Greek is one of the two official languages of Cyprus, and the country's main language. Small communities of Greek speakers exist all around the Middle East; until the 20th century it was also widely spoken in Asia Minor (being the second most spoken language there, after Turkish) and Egypt. During the antiquity, Ancient Greek was the lingua franca for many areas of the western Middle East and until the Muslim expansion it was widely spoken there as well. Until the late 11th century, it was also the main spoken language in Asia Minor; after that it was gradually replaced by the Turkish language as the Anatolian Turks expanded and the local Greeks were assimilated, especially in the interior. English is one of the official languages of Akrotiri and Dhekelia. It is also commonly taught and used as a foreign second language, in countries such as Egypt, Jordan, Iran, Iraq, Qatar, Bahrain, United Arab Emirates and Kuwait. It is also a main language in some Emirates of the United Arab Emirates. It is also spoken as native language by Jewish immigrants from Anglophone countries (UK, US, Australia) in Israel and understood widely as second language there. French is taught and used in many government facilities and media in Lebanon, and is taught in some primary and secondary schools of Egypt and Syria. Maltese, a Semitic language mainly spoken in Europe, is used by the Franco-Maltese diaspora in Egypt. Due to widespread immigration of French Jews to Israel, it is the native language of approximately 200,000 Jews in Israel. Armenian speakers are to be found in the region. Georgian is spoken by the Georgian diaspora. Russian is spoken by a large portion of the Israeli population, because of emigration in the late 1990s. Russian today is a popular unofficial language in use in Israel; news, radio and sign boards can be found in Russian around the country after Hebrew and Arabic. Circassian is also spoken by the diaspora in the region and by almost all Circassians in Israel who speak Hebrew and English as well. The largest Romanian-speaking community in the Middle East is found in Israel, where as of 1995[update] Romanian is spoken by 5% of the population.[d] Bengali, Hindi and Urdu are widely spoken by migrant communities in many Middle Eastern countries, such as Saudi Arabia (where 20–25% of the population is South Asian), the United Arab Emirates (where 50–55% of the population is South Asian), and Qatar, which have large numbers of Pakistani, Bangladeshi and Indian immigrants. Culture The Middle East has recently become more prominent in hosting global sport events due to its wealth and desire to diversify its economy. The South Asian diaspora is a major backer of cricket in the region. See also Notes References Further reading External links 29°N 41°E / 29°N 41°E / 29; 41 |
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[SOURCE: https://en.wikipedia.org/wiki/Speed_of_light] | [TOKENS: 10135] |
Contents Speed of light The speed of light in vacuum, often called simply the speed of light and commonly denoted c, is a universal physical constant exactly equal to 299792458 m⋅s−1. It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time interval of 1⁄299792458 second. The value 299,792,458 metres per second is approximately 1 billion kilometres per hour; 700 million miles per hour. The speed of light is the same for all observers, no matter their relative velocity. It is the upper limit for the speed at which information, matter, or energy can travel through space. All forms of electromagnetic radiation, including visible light, travel in vacuum at the speed c. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and sensitive measurements, their finite speed has noticeable effects. Much starlight viewed on Earth is from the distant past, allowing humans to study the history of the universe by viewing distant objects. When communicating with distant space probes, it can take hours for signals to travel. In computing, the speed of light fixes the ultimate minimum communication delay. The speed of light can be used in time of flight measurements to measure large distances to extremely high precision. Ole Rømer first demonstrated that light does not travel instantaneously by studying the apparent motion of Jupiter's moon Io. In an 1865 paper, James Clerk Maxwell proposed that light was an electromagnetic wave and, therefore, travelled at speed c. Albert Einstein postulated that the speed of light c with respect to any inertial frame of reference is a constant and is independent of the motion of the light source. He explored the consequences of that postulate by deriving the theory of relativity, and so showed that the parameter c had relevance outside of the context of light and electromagnetism. Massless particles and field perturbations, such as gravitational waves, also travel at speed c in vacuum. Such particles and waves travel at c regardless of the motion of the source or the inertial reference frame of the observer. Particles with nonzero rest mass can be accelerated to approach c but can never reach it, regardless of the frame of reference in which their speed is measured. In the theory of relativity, c interrelates space and time and appears in the famous mass–energy equivalence, E = mc2. In some cases, objects or waves may appear to travel faster than light. The expansion of the universe is understood to exceed the speed of light beyond a certain boundary. The speed at which light propagates through transparent materials, such as glass or air, is less than c; similarly, the speed of electromagnetic waves around wire cables (the speed of electricity) is slower than c. The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c/v). For example, for visible light, the refractive index of glass is typically around 1.5, meaning that light in glass travels at c/1.5 ≈ 200000 km/s (124000 mi/s); the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s (56 mi/s) slower than c. Notation The speed of light in vacuum is usually denoted by a lowercase c. The origin of the letter choice is unclear, with guesses including "c" for "constant" or the Latin celeritas (meaning 'swiftness, celerity'). The "c" was used for "celerity" meaning a velocity in books by Leonhard Euler and others, but this velocity was not specifically for light; Isaac Asimov wrote a popular science article, "C for Celeritas", but did not explain the origin. In 1856, Wilhelm Eduard Weber and Rudolf Kohlrausch had used c for a different constant that was later shown to equal √2 times the speed of light in vacuum. Historically, the symbol V was used as an alternative symbol for the speed of light, introduced by James Clerk Maxwell in 1865. In 1903, Max Abraham used c with its modern meaning in a widely read textbook on electromagnetism. Einstein used V in his original German-language papers on special relativity in 1905, but in 1907 he switched to c, which by then had become the standard symbol for the speed of light. Sometimes c is used for the speed of waves in any material medium, and c0 for the speed of light in vacuum. This subscripted notation, which is endorsed in official SI literature, has the same form as related electromagnetic constants: namely, μ0 for the vacuum permeability or magnetic constant, ε0 for the vacuum permittivity or electric constant, and Z0 for the impedance of free space. This article uses c exclusively for the speed of light in vacuum. In unit systems Since 1983, the constant c has been defined in the International System of Units (SI) as exactly 299792458 m/s; this relationship is used to define the metre as exactly the distance that light travels in vacuum in 1⁄299792458 of a second. The second is, in turn, defined to be the length of time occupied by 9192631770 cycles of the radiation emitted by a caesium-133 atom in a transition between two specified energy states. By using the value of c, as well as an accurate measurement of the second, one can establish a standard for the metre. The particular value chosen for the speed of light provided a more accurate definition of the metre that still agreed as much as possible with the definition used before 1983. As a dimensional physical constant, the numerical value of c is different for different unit systems. For example, in imperial units, the speed of light is approximately 186282 miles per second. This is value is less than 2% different from 1 billion feet per second or one foot per nanosecond. Naval officer and computer scientist Grace Murray Hopper distributed foot-long wires to colleagues in the late 1960 to visually illustrate the importance of designing smaller components to increase computing speed. In branches of physics in which c appears often, such as in relativity, it is common to use systems of natural units of measurement or the geometrized unit system where c = 1. Using these units, c does not appear explicitly because multiplication or division by 1 does not affect the result. Its unit of light-second per second is still relevant, even if omitted. Fundamental role in physics The speed at which light waves propagate in vacuum is independent both of the motion of the wave source and of the inertial frame of reference of the observer. This invariance of the speed of light was postulated by Einstein in 1905, after being motivated by Maxwell's theory of electromagnetism and the lack of evidence for motion against the luminiferous aether. Experiments such as the Kennedy–Thorndike experiment and the Ives–Stilwell experiment have shown this postulate to match experimental observations. The special theory of relativity explores the consequences of this invariance of c with the assumption that the laws of physics are the same in all inertial frames of reference. One consequence is that c is the speed at which all massless particles and waves, including light, must travel in vacuum. Special relativity has many counterintuitive and experimentally verified implications. These include the equivalence of mass and energy (E = mc2), length contraction (moving objects shorten), Terrell rotation (apparent rotation), and time dilation (moving clocks run more slowly). The factor γ by which lengths contract and times dilate is known as the Lorentz factor and is given by γ = (1 − v2/c2)−1/2, where v is the speed of the object. The difference of γ from 1 is negligible for speeds much slower than c, such as most everyday speeds – in which case special relativity is closely approximated by Galilean relativity – but it increases at relativistic speeds and diverges to infinity as v approaches c. For example, a time dilation factor of γ = 2 occurs at a relative velocity of 86.6% of the speed of light (v = 0.866c). Similarly, a time dilation factor of γ = 10 occurs at 99.5% the speed of light (v = 0.995c). The results of special relativity can be summarized by treating space and time as a unified structure known as spacetime (with c relating the units of space and time), and requiring that physical theories satisfy a special symmetry called Lorentz invariance, whose mathematical formulation contains the parameter c. Lorentz invariance is an almost universal assumption for modern physical theories, such as quantum electrodynamics, quantum chromodynamics, the Standard Model of particle physics, and general relativity. As such, the parameter c is ubiquitous in modern physics, appearing in many contexts that are unrelated to light. For example, general relativity predicts that c is also the speed of gravity and of gravitational waves, and observations of gravitational waves have been consistent with this prediction. In non-inertial frames of reference (gravitationally curved spacetime or accelerated reference frames), the local speed of light is constant and equal to c, but the speed of light can differ from c when measured from a remote frame of reference, depending on how measurements are extrapolated to the region. It is generally assumed that fundamental constants such as c have the same value throughout spacetime, meaning that they do not depend on location and do not vary with time. However, it has been suggested in various theories that the speed of light may have changed over time. No conclusive evidence for such changes has been found, but they remain the subject of ongoing research. It is generally assumed that the two-way speed of light is isotropic, meaning that it has the same value regardless of the direction in which it is measured. Observations of the emissions from nuclear energy levels as a function of the orientation of the emitting nuclei in a magnetic field (see Hughes–Drever experiment), and of rotating optical resonators (see Resonator experiments) have put stringent limits on the possible two-way anisotropy. An object with rest mass m and speed v relative to a laboratory has kinetic energy (γ − 1)mc2 with respect to that lab, where γ is the Lorentz factor defined above. The γ factor approaches infinity as v approaches c, and it would take an infinite amount of energy to accelerate an object with mass to the speed of light.: 13.3 The speed of light is the upper limit for the speeds of objects with positive rest mass. Analysis of individual photons confirm that information cannot travel faster than the speed of light. This is experimentally established in many tests of relativistic energy and momentum. More generally, it is impossible for signals or energy to travel faster than c. One argument for this is known as causality. If the spatial distance between two events A and B is greater than the time interval between them multiplied by c then there are frames of reference in which A precedes B, others in which B precedes A, and others in which they are simultaneous. As a result, if something were travelling faster than c relative to an inertial frame of reference, it would be travelling backwards in time relative to another frame, and causality would be violated.: 497 In such a frame of reference, an "effect" could be observed before its "cause". Such a violation of causality has never been recorded, and would lead to paradoxes such as the tachyonic antitelephone. In some theoretical treatments, the Scharnhorst effect allows signals to travel faster than c, by one part in 1036. However other approaches to the same physical set up show no such effect. and it appears the special conditions in which this effect might occur would prevent one from using it to violate causality. It is only possible to verify experimentally that the two-way speed of light (for example, from a source to a mirror and back again) is frame-independent, because it is impossible to measure the one-way speed of light (for example, from a source to a distant detector) without some convention as to how clocks at the source and at the detector should be synchronized. By adopting Einstein synchronization for the clocks, the one-way speed of light becomes equal to the two-way speed of light by definition. Faster-than-light observations and experiments There are situations in which it may seem that matter, energy, or information-carrying signal travels at speeds greater than c, but they do not. For example, as is discussed in the propagation of light in a medium section below, many wave velocities can exceed c. The phase velocity of X-rays through most glasses can routinely exceed c, but phase velocity does not determine the velocity at which waves convey information. If a laser beam is swept quickly across a distant object, the spot of light can move faster than c, although the initial movement of the spot is delayed because of the time it takes light to get to the distant object at the speed c. However, the only physical entities that are moving are the laser and its emitted light, which travels at the speed c from the laser to the various positions of the spot. Similarly, a shadow projected onto a distant object can be made to move faster than c, after a delay in time. In neither case does any matter, energy, or information travel faster than light. The rate of change in the distance between two objects in a frame of reference with respect to which both are moving (their closing speed) may have a value in excess of c. However, this does not represent the speed of any single object as measured in a single inertial frame. Certain quantum effects appear to be transmitted instantaneously and therefore faster than c, as in the EPR paradox. An example involves the quantum states of two particles that can be entangled. Until either of the particles is observed, they exist in a superposition of two quantum states. If the particles are separated and one particle's quantum state is observed, the other particle's quantum state is determined instantaneously. However, it is impossible to control which quantum state the first particle will take on when it is observed, so information cannot be transmitted in this manner. Another quantum effect that predicts the occurrence of faster-than-light speeds is called the Hartman effect: under certain conditions the time needed for a virtual particle to tunnel through a barrier is constant, regardless of the thickness of the barrier. This could result in a virtual particle crossing a large gap faster than light. However, no information can be sent using this effect. So-called superluminal motion is seen in certain astronomical objects, such as the relativistic jets of radio galaxies and quasars. However, these jets are not moving at speeds in excess of the speed of light: the apparent superluminal motion is a projection effect caused by objects moving near the speed of light and approaching Earth at a small angle to the line of sight: since the light which was emitted when the jet was farther away took longer to reach the Earth, the time between two successive observations corresponds to a longer time between the instants at which the light rays were emitted. A 2011 experiment where neutrinos were observed to travel faster than light turned out to be due to experimental error. In models of the expanding universe, the farther galaxies are from each other, the faster they drift apart. For example, galaxies far away from Earth are inferred to be moving away from the Earth with speeds proportional to their distances. Beyond a boundary called the Hubble sphere, the rate at which their distance from Earth increases becomes greater than the speed of light. These recession rates, defined as the increase in proper distance per cosmological time, are not velocities in a relativistic sense. Faster-than-light cosmological recession speeds are only a coordinate artifact. Propagation of light In classical physics, light is described as a type of electromagnetic wave. The classical behaviour of the electromagnetic field is described by Maxwell's equations, which predict that the speed c with which electromagnetic waves (such as light) propagate in vacuum is related to the distributed capacitance and inductance of vacuum, otherwise respectively known as the electric constant ε0 and the magnetic constant μ0, by the equation c = 1 ε 0 μ 0 . {\displaystyle c={\frac {1}{\sqrt {\varepsilon _{0}\mu _{0}}}}.} In modern quantum physics, the electromagnetic field is described by the theory of quantum electrodynamics (QED). In this theory, light is described by the fundamental excitations (or quanta) of the electromagnetic field, called photons. In QED, photons are massless particles and thus, according to special relativity, they travel at the speed of light in vacuum. Extensions of QED in which the photon has a mass have been considered. In such a theory, its speed would depend on its frequency, and the invariant speed c of special relativity would then be the upper limit of the speed of light in vacuum. No variation of the speed of light with frequency has been observed in rigorous testing, putting stringent limits on the mass of the photon. The limit obtained depends on the model used: if the massive photon is described by Proca theory, the experimental upper bound for its mass is about ×10−57 grams; if photon mass is generated by a Higgs mechanism, the experimental upper limit is less sharp, m ≤ 10−14 eV/c2 (roughly 2×10−47 g). Another reason for the speed of light to vary with its frequency would be the failure of special relativity to apply to arbitrarily small scales, as predicted by some proposed theories of quantum gravity. In 2009, the observation of gamma-ray burst GRB 090510 found no evidence for a dependence of photon speed on energy, supporting tight constraints in specific models of spacetime quantization on how this speed is affected by photon energy for energies approaching the Planck scale. In a medium, light usually does not propagate at a speed equal to c; further, different types of light wave will travel at different speeds. The speed at which the individual crests and troughs of a plane wave (a wave filling the whole space, with only one frequency) propagate is called the phase velocity vp. A physical signal with a finite extent (a pulse of light) travels at a different speed. The overall envelope of the pulse travels at the group velocity vg, and its earliest part travels at the front velocity vf. The phase velocity is important in determining how a light wave travels through a material or from one material to another. It is often represented in terms of a refractive index. The refractive index of a material is defined as the ratio of c to the phase velocity vp in the material: larger indices of refraction indicate lower speeds. The refractive index of a material may depend on the light's frequency, intensity, polarization, or direction of propagation; in many cases, though, it can be treated as a material-dependent constant. The refractive index of air is approximately 1.0003. Denser media, such as water, glass, and diamond, have refractive indexes of around 1.3, 1.5 and 2.4, respectively, for visible light. In exotic materials like Bose–Einstein condensates near absolute zero, the effective speed of light may be only a few metres per second. However, this represents absorption and re-radiation delay between atoms, as do all slower-than-c speeds in material substances. As an extreme example of light "slowing" in matter, two independent teams of physicists claimed to bring light to a "complete standstill" by passing it through a Bose–Einstein condensate of the element rubidium. The popular description of light being "stopped" in these experiments refers only to light being stored in the excited states of atoms, then re-emitted at an arbitrarily later time, as stimulated by a second laser pulse. During the time it had "stopped", it had ceased to be light. This type of behaviour is generally microscopically true of all transparent media which "slow" the speed of light. In transparent materials, the refractive index generally is greater than 1, meaning that the phase velocity is less than c. In other materials, it is possible for the refractive index to become smaller than 1 for some frequencies; in some exotic materials it is even possible for the index of refraction to become negative. The requirement that causality is not violated implies that the real and imaginary parts of the dielectric constant of any material, corresponding respectively to the index of refraction and to the attenuation coefficient, are linked by the Kramers–Kronig relations. In practical terms, this means that in a material with refractive index less than 1, the wave will be absorbed quickly. A pulse with different group and phase velocities (which occurs if the phase velocity is not the same for all the frequencies of the pulse) smears out over time, a process known as dispersion. Certain materials have an exceptionally low (or even zero) group velocity for light waves, a phenomenon called slow light. The opposite, group velocities exceeding c, was proposed theoretically in 1993 and achieved experimentally in 2000. It should even be possible for the group velocity to become infinite or negative, with pulses travelling instantaneously or backwards in time. None of these options allow information to be transmitted faster than c. It is impossible to transmit information with a light pulse any faster than the speed of the earliest part of the pulse (the front velocity). It can be shown that this is (under certain assumptions) always equal to c. It is possible for a particle to travel through a medium faster than the phase velocity of light in that medium (but still slower than c). When a charged particle does that in a dielectric material, the electromagnetic equivalent of a shock wave, known as Cherenkov radiation, is emitted. Practical effects of finiteness The speed of light is of relevance to telecommunications: the one-way and round-trip delay time are greater than zero. This applies from small to astronomical scales. On the other hand, some techniques depend on the finite speed of light, for example in distance measurements. In computers, the speed of light imposes a limit on how quickly data can be sent between processors. If a processor operates at 1 gigahertz, a signal can travel only a maximum of about 30 centimetres (1 ft) in a single clock cycle – in practice, this distance is even shorter since the printed circuit board refracts and slows down signals. Processors must therefore be placed close to each other, as well as memory chips, to minimize communication latencies, and care must be exercised when routing wires between them to ensure signal integrity. If clock frequencies continue to increase, the speed of light may eventually become a limiting factor for the internal design of single chips. Given that the equatorial circumference of the Earth is about 40075 km and that c is about 300000 km/s, the theoretical shortest time for a piece of information to travel half the globe along the surface is about 67 milliseconds. When light is traveling in optical fibre (a transparent material) the actual transit time is longer, in part because the speed of light is slower by about 35% in optical fibre with an refractive index n around 1.52. Straight lines are rare in global communications and the travel time increases when signals pass through electronic switches or signal regenerators. Although this distance is largely irrelevant for most applications, latency becomes important in fields such as high-frequency trading, where traders seek to gain minute advantages by delivering their trades to exchanges fractions of a second ahead of other traders. For example, traders have been switching to microwave communications between trading hubs, because of the advantage which radio waves travelling at near to the speed of light through air have over comparatively slower fibre optic signals. Similarly, communications between the Earth and spacecraft are not instantaneous. There is a brief delay from the source to the receiver, which becomes more noticeable as distances increase. This delay was significant for communications between ground control and Apollo 8 when it became the first crewed spacecraft to orbit the Moon: for every question, the ground control station had to wait at least three seconds for the answer to arrive. The communications delay between Earth and Mars can vary between five and twenty minutes depending upon the relative positions of the two planets. As a consequence of this, if a robot on the surface of Mars were to encounter a problem, its human controllers would not be aware of it until approximately 4–24 minutes later. It would then take a further 4–24 minutes for commands to travel from Earth to Mars. Receiving light and other signals from distant astronomical sources takes much longer. For example, it takes 13 billion (13×109) years for light to travel to Earth from the faraway galaxies viewed in the Hubble Ultra-Deep Field images. Those photographs, taken today, capture images of the galaxies as they appeared 13 billion years ago, when the universe was less than a billion years old. The fact that more distant objects appear to be younger, due to the finite speed of light, allows astronomers to infer the evolution of stars, of galaxies, and of the universe itself. Astronomical distances are sometimes expressed in light-years, especially in popular science publications and media. A light-year is the distance light travels in one Julian year, around 9461 billion kilometres, 5879 billion miles, or 0.3066 parsecs. In round figures, a light year is nearly 10 trillion kilometres or nearly 6 trillion miles. Proxima Centauri, the closest star to Earth after the Sun, is around 4.2 light-years away. Radar systems measure the distance to a target by the time it takes a radio-wave pulse to return to the radar antenna after being reflected by the target: the distance to the target is half the round-trip transit time multiplied by the speed of light. A Global Positioning System (GPS) receiver measures its distance to GPS satellites based on how long it takes for a radio signal to arrive from each satellite, and from these distances calculates the receiver's position. Because light travels about 300000 kilometres (186000 miles) in one second, these measurements of small fractions of a second must be very precise. The Lunar Laser Ranging experiment, radar astronomy and the Deep Space Network determine distances to the Moon, planets and spacecraft, respectively, by measuring round-trip transit times. Determination There are different ways to determine the value of c. One way is to measure directly the speed at which light waves propagate, which can be done in various astronomical and Earth-based setups. It is also possible to determine c from other physical laws where it appears, for example, by determining the values of the electromagnetic constants ε0 and μ0 and using their relation to c. Historically, the most accurate results have been obtained by separately determining the frequency and wavelength of a light beam, with their product equalling c. This is described in more detail in the "Interferometry" section below. In 1983 the metre was defined as "the length of the path travelled by light in vacuum during a time interval of 1⁄299792458 of a second", fixing the value of the speed of light at 299792458 m/s by definition, as described below. Consequently, accurate measurements of the speed of light yield an accurate realization of the metre rather than an accurate value of c. Outer space is a convenient setting for measuring the speed of light because of its large scale and nearly perfect vacuum. Typically, one measures the time needed for light to traverse some reference distance in the Solar System, such as the radius of the Earth's orbit. Historically, such measurements could be made fairly accurately, compared to how accurately the length of the reference distance is known in Earth-based units. Ole Rømer used an astronomical measurement to make the first quantitative estimate of the speed of light in the year 1676. When measured from Earth, the periods of moons orbiting a distant planet are shorter when the Earth is approaching the planet than when the Earth is receding from it. The difference is small, but the cumulative time becomes significant when measured over months. The distance travelled by light from the planet (or its moon) to Earth is shorter when the Earth is at the point in its orbit that is closest to its planet than when the Earth is at the farthest point in its orbit, the difference in distance being the diameter of the Earth's orbit around the Sun. The observed change in the moon's orbital period is caused by the difference in the time it takes light to traverse the shorter or longer distance. Rømer observed this effect for Jupiter's innermost major moon Io and deduced that light takes 22 minutes to cross the diameter of the Earth's orbit. Another method is to use the aberration of light, discovered and explained by James Bradley in the 18th century. This effect results from the vector addition of the velocity of light arriving from a distant source (such as a star) and the velocity of its observer (see diagram on the right). A moving observer thus sees the light coming from a slightly different direction and consequently sees the source at a position shifted from its original position. Since the direction of the Earth's velocity changes continuously as the Earth orbits the Sun, this effect causes the apparent position of stars to move around. From the angular difference in the position of stars (maximally 20.5 arcseconds) it is possible to express the speed of light in terms of the Earth's velocity around the Sun, which with the known length of a year can be converted to the time needed to travel from the Sun to the Earth. In 1729, Bradley used this method to derive that light travelled 10210 times faster than the Earth in its orbit (the modern figure is 10066 times faster) or, equivalently, that it would take light 8 minutes 12 seconds to travel from the Sun to the Earth. Historically the speed of light was used together with timing measurements to determine a value for the astronomical unit (AU). The astronomical unit was redefined in 2012 as exactly 149597870700 m. This redefinition is analogous to that of the metre and likewise has the effect of fixing the speed of light to an exact value in astronomical units per second (via the exact speed of light in metres per second). A method of measuring the speed of light is to measure the time needed for light to travel to a mirror at a known distance and back. This is the working principle behind experiments by Hippolyte Fizeau and Léon Foucault. The setup as used by Fizeau consists of a beam of light directed at a mirror 8 kilometres (5 mi) away. On the way from the source to the mirror, the beam passes through a rotating cogwheel. At a certain rate of rotation, the beam passes through one gap on the way out and another on the way back, but at slightly higher or lower rates, the beam strikes a tooth and does not pass through the wheel. Knowing the distance between the wheel and the mirror, the number of teeth on the wheel, and the rate of rotation, the speed of light can be calculated. The method of Foucault replaces the cogwheel with a rotating mirror. Because the mirror keeps rotating while the light travels to the distant mirror and back, the light is reflected from the rotating mirror at a different angle on its way out than it is on its way back. From this difference in angle, the known speed of rotation and the distance to the distant mirror the speed of light may be calculated. Foucault used this apparatus to measure the speed of light in air versus water, based on a suggestion by François Arago. Today, using oscilloscopes with time resolutions of less than one nanosecond, the speed of light can be directly measured by timing the delay of a light pulse from a laser or an LED reflected from a mirror. This method is less precise (with errors of the order of 1%) than other modern techniques, but it is sometimes used as a laboratory experiment in college physics classes. An option for deriving c that does not directly depend on a measurement of the propagation of electromagnetic waves is to use the relation between c and the vacuum permittivity ε0 and vacuum permeability μ0 established by Maxwell's theory: c2 = 1/(ε0μ0). The vacuum permittivity may be determined by measuring the capacitance and dimensions of a capacitor, whereas the value of the vacuum permeability was historically fixed at exactly 4π×10−7 H⋅m−1 through the definition of the ampere. Rosa and Dorsey used this method in 1907 to find a value of 299710±22 km/s. Their method depended upon having a standard unit of electrical resistance, the "international ohm", and so its accuracy was limited by how this standard was defined. Another way to measure the speed of light is to independently measure the frequency f and wavelength λ of an electromagnetic wave in vacuum. The value of c can then be found by using the relation c = λf. One option is to measure the resonance frequency of a cavity resonator. If the dimensions of the resonance cavity are also known, these can be used to determine the wavelength of the wave. In 1946, Louis Essen and A. C. Gordon-Smith established the frequency for a variety of normal modes of microwaves of a microwave cavity of precisely known dimensions. The dimensions were established to an accuracy of about ±0.8 μm using gauges calibrated by interferometry. As the wavelength of the modes was known from the geometry of the cavity and from electromagnetic theory, knowledge of the associated frequencies enabled a calculation of the speed of light. The Essen–Gordon-Smith result, 299792±9 km/s, was substantially more precise than those found by optical techniques. By 1950, repeated measurements by Essen established a result of 299792.5±3.0 km/s. A household demonstration of this technique is possible, using a microwave oven and food such as marshmallows or margarine: if the turntable is removed so that the food does not move, it will cook the fastest at the antinodes (the points at which the wave amplitude is the greatest), where it will begin to melt. The distance between two such spots is half the wavelength of the microwaves; by measuring this distance and multiplying the wavelength by the microwave frequency (usually displayed on the back of the oven, typically 2450 MHz), the value of c can be calculated, "often with less than 5% error". Interferometry is another method to find the wavelength of electromagnetic radiation for determining the speed of light. A coherent beam of light (e.g. from a laser), with a known frequency f, is split to follow two paths and then recombined. By adjusting the path length while observing the interference pattern and carefully measuring the change in path length, the wavelength of the light λ can be determined. The speed of light is then calculated using the equation c = λf. Before the advent of laser technology, coherent radio sources were used for interferometry measurements of the speed of light. Interferometric determination of wavelength becomes less precise with wavelength and the experiments were thus limited in precision by the long wavelength (~4 mm [0.16 in]) of the radiowaves. The precision can be improved by using light with a shorter wavelength, but then it becomes difficult to directly measure the frequency of the light. One way around this problem is to start with a low frequency signal of which the frequency can be precisely measured, and from this signal progressively synthesize higher frequency signals whose frequency can then be linked to the original signal. A laser can then be locked to the frequency, and its wavelength can be determined using interferometry. This technique was due to a group at the National Bureau of Standards (which later became the National Institute of Standards and Technology). They used it in 1972 to measure the speed of light in vacuum with a fractional uncertainty of 3.5×10−9. History Until the early modern period, it was not known whether light travelled instantaneously or at a very fast finite speed. The first extant recorded examination of this subject was in ancient Greece. The ancient Greeks, Arabic scholars, and classical European scientists long debated this until Rømer provided the first calculation of the speed of light. Einstein's theory of special relativity postulates that the speed of light is constant regardless of one's frame of reference. Since then, scientists have provided increasingly accurate measurements. Empedocles (c. 490–430 BCE) was the first to propose a theory of light and claimed that light has a finite speed. He maintained that light was something in motion, and therefore must take some time to travel. Aristotle argued, to the contrary, that "light is due to the presence of something, but it is not a movement". Euclid and Ptolemy advanced Empedocles' emission theory of vision, where light is emitted from the eye, thus enabling sight. Based on that theory, Heron of Alexandria argued that the speed of light must be infinite because distant objects such as stars appear immediately upon opening the eyes. Early Islamic philosophers initially agreed with the Aristotelian view that light had no speed of travel. In 1021, Alhazen (Ibn al-Haytham) published the Book of Optics, in which he presented a series of arguments dismissing the emission theory of vision in favour of the now accepted intromission theory, in which light moves from an object into the eye. This led Alhazen to propose that light must have a finite speed, and that the speed of light is variable, decreasing in denser bodies. He argued that light is substantial matter, the propagation of which requires time, even if this is hidden from the senses. Also in the 11th century, Abū Rayhān al-Bīrūnī agreed that light has a finite speed, and observed that the speed of light is much faster than the speed of sound. In the 13th century, Roger Bacon argued that the speed of light in air was not infinite, using philosophical arguments backed by the writing of Alhazen and Aristotle. In the 1270s, Witelo considered the possibility of light travelling at infinite speed in vacuum, but slowing down in denser bodies. In the early 17th century, Johannes Kepler believed that the speed of light was infinite since empty space presents no obstacle to it. René Descartes argued that if the speed of light were to be finite, the Sun, Earth, and Moon would be noticeably out of alignment during a lunar eclipse. Although this argument fails when aberration of light is taken into account, the latter was not recognized until the following century. Since such misalignment had not been observed, Descartes concluded the speed of light was infinite. Descartes speculated that if the speed of light were found to be finite, his whole system of philosophy might be demolished. Despite this, in his derivation of Snell's law, Descartes assumed that some kind of motion associated with light was faster in denser media. Pierre de Fermat derived Snell's law using the opposing assumption, the denser the medium the slower light travelled. Fermat also argued in support of a finite speed of light. In 1629, Isaac Beeckman proposed an experiment in which a person observes the flash of a cannon reflecting off a mirror about one mile (1.6 km) away. In 1638, Galileo Galilei proposed an experiment, with an apparent claim to having performed it some years earlier, to measure the speed of light by observing the delay between uncovering a lantern and its perception some distance away. He was unable to distinguish whether light travel was instantaneous or not, but concluded that if it were not, it must nevertheless be extraordinarily rapid. According to Galileo, the lanterns he used were "at a short distance, less than a mile". Assuming the distance was not too much shorter than a mile, and that "about a thirtieth of a second is the minimum time interval distinguishable by the unaided eye", Boyer notes that Galileo's experiment could at best be said to have established a lower limit of about 60 miles per second for the velocity of light. In 1667, the Accademia del Cimento of Florence reported that it had performed Galileo's experiment, with the lanterns separated by about one mile, but no delay was observed. The actual delay in this experiment would have been about 11 microseconds. The first quantitative estimate of the speed of light was made in 1676 by Ole Rømer. From the observation that the periods of Jupiter's innermost moon Io appeared to be shorter when the Earth was approaching Jupiter than when receding from it, he concluded that light travels at a finite speed, and estimated that it takes light 22 minutes to cross the diameter of Earth's orbit. Christiaan Huygens combined this estimate with an estimate for the diameter of the Earth's orbit to obtain an estimate of speed of light of 220000 km/s, which is 27% lower than the actual value. In his 1704 book Opticks, Isaac Newton reported Rømer's calculations of the finite speed of light and gave a value of "seven or eight minutes" for the time taken for light to travel from the Sun to the Earth (the modern value is 8 minutes 19 seconds). Newton queried whether Rømer's eclipse shadows were coloured. Hearing that they were not, he concluded the different colours travelled at the same speed. In 1729, James Bradley discovered stellar aberration. From this effect he determined that light must travel 10,210 times faster than the Earth in its orbit (the modern figure is 10,066 times faster) or, equivalently, that it would take light 8 minutes 12 seconds to travel from the Sun to the Earth. In the 19th century Hippolyte Fizeau developed a method to determine the speed of light based on time-of-flight measurements on Earth and reported a value of 315000 km/s. His method was improved upon by Léon Foucault who obtained a value of 298000 km/s in 1862. In the year 1856, Wilhelm Eduard Weber and Rudolf Kohlrausch measured the ratio of the electromagnetic and electrostatic units of charge, 1/√ε0μ0, by discharging a Leyden jar, and found that its numerical value was very close to the speed of light as measured directly by Fizeau. The following year Gustav Kirchhoff calculated that an electric signal in a resistanceless wire travels along the wire at this speed. In the early 1860s, Maxwell showed that, according to the theory of electromagnetism he was working on, electromagnetic waves propagate in empty space at a speed equal to the above Weber/Kohlrausch ratio, and drawing attention to the numerical proximity of this value to the speed of light as measured by Fizeau, he proposed that light is in fact an electromagnetic wave. Maxwell backed up his claim with his own experiment published in the 1868 Philosophical Transactions which determined the ratio of the electrostatic and electromagnetic units of electricity. The wave properties of light were well known since Thomas Young. In the 19th century, physicists believed light was propagating in a medium called aether (or ether). After Maxwell's theory unified light and electric and magnetic waves, it was favored that both light and electric magnetic waves propagate in the same aether medium (or called the luminiferous aether). Some physicists thought that this aether acted as a preferred frame of reference for the propagation of light and therefore it should be possible to measure the motion of the Earth with respect to this medium, by measuring the isotropy of the speed of light. Beginning in the 1880s several experiments were performed to try to detect this motion, the most famous of which is the experiment performed by Albert A. Michelson and Edward W. Morley in 1887. The detected motion was found to always be nil (within observational error). Modern experiments indicate that the two-way speed of light is isotropic (the same in every direction) to within 6 nanometres per second. Because of Michelson-Morley experiment Hendrik Lorentz proposed that the motion of the apparatus through the aether may cause the apparatus to contract along its length in the direction of motion, and he further assumed that the time variable for moving systems must also be changed accordingly ("local time"), which led to the formulation of the Lorentz transformation. Based on Lorentz's aether theory, Henri Poincaré (1900) showed that this local time (to first order in v/c) is indicated by clocks moving in the aether, which are synchronized under the assumption of constant light speed. In 1904, he speculated that the speed of light could be a limiting velocity in dynamics, provided that the assumptions of Lorentz's theory are all confirmed. In 1905, Poincaré brought Lorentz's aether theory into full observational agreement with the principle of relativity. In 1905 Einstein postulated from the outset that the speed of light in vacuum, measured by a non-accelerating observer, is independent of the motion of the source or observer. Using this and the principle of relativity as a basis he derived the special theory of relativity, in which the speed of light in vacuum c featured as a fundamental constant, also appearing in contexts unrelated to light. This made the concept of the stationary aether (to which Lorentz and Poincaré still adhered) useless and revolutionized the concepts of space and time. In the second half of the 20th century, much progress was made in increasing the accuracy of measurements of the speed of light, first by cavity resonance techniques and later by laser interferometer techniques. These were aided by new, more precise, definitions of the metre and second. In 1950, Louis Essen determined the speed as 299792.5±3.0 km/s, using cavity resonance. This value was adopted by the 12th General Assembly of the Radio-Scientific Union in 1957. In 1960, the metre was redefined in terms of the wavelength of a particular spectral line of krypton-86, and, in 1967, the second was redefined in terms of the hyperfine transition frequency of the ground state of caesium-133. In 1972, using the laser interferometer method and the new definitions, a group at the US National Bureau of Standards in Boulder, Colorado determined the speed of light in vacuum to be c = 299792456.2±1.1 m/s. This was 100 times less uncertain than the previously accepted value. The remaining uncertainty was mainly related to the definition of the metre. As similar experiments found comparable results for c, the 15th General Conference on Weights and Measures in 1975 recommended using the value 299792458 m/s for the speed of light. In 1983 the 17th meeting of the General Conference on Weights and Measures (CGPM) found that wavelengths from frequency measurements and a given value for the speed of light are more reproducible than the previous standard. They kept the 1967 definition of second, so the caesium hyperfine frequency would now determine both the second and the metre. To do this, they redefined the metre as "the length of the path traveled by light in vacuum during a time interval of 1/299792458 of a second". As a result of this definition, the value of the speed of light in vacuum is exactly 299792458 m/s and has become a defined constant in the SI system of units. Improved experimental techniques that, prior to 1983, would have measured the speed of light no longer affect the known value of the speed of light in SI units, but instead allow a more precise realization of the metre by more accurately measuring the wavelength of krypton-86 and other light sources. In 2011, the CGPM stated its intention to redefine all seven SI base units using what it calls "the explicit-constant formulation", where each "unit is defined indirectly by specifying explicitly an exact value for a well-recognized fundamental constant", as was done for the speed of light. It proposed a new, but completely equivalent, wording of the metre's definition: "The metre, symbol m, is the unit of length; its magnitude is set by fixing the numerical value of the speed of light in vacuum to be equal to exactly 299792458 when it is expressed in the SI unit m s−1." This was one of the changes that was incorporated in the 2019 revision of the SI, also termed the New SI. See also Notes References Further reading External links |
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[SOURCE: https://en.wikipedia.org/wiki/Protel] | [TOKENS: 1184] |
Contents Protel Protel stands for "Procedure Oriented Type Enforcing Language". Protel is a programming language designed in 1975 by Nortel Networks and used on telecommunications switching systems such as the DMS-100. Protel-2 is the object-oriented version of Protel. The PROTEL language was designed to meet the needs of digital telephony and is the basis of the DMS-100 line of switching systems. PROTEL is a strongly typed, block-structured language which is based heavily on PASCAL and ALGOL 68 with left-to-right style of variable assignment, variable-sized arrays, and extensible structures. The designers of PROTEL significantly extended PASCAL of the day by adding external compilation and extending the data structures available in the language. The PROTEL compiler is tightly integrated with the operating system (SOS), application (CALLP), the development environment (PLS) and originally the processor (NT40). PLS, SOS, CALLP and the compiler itself are all written in PROTEL. Any description of the PROTEL language can't help but include some aspects of the other components. PROTEL has very strict type enforcement but the tight coupling of the components creates opportunities to bypass some type checking for skilled coders by using internal compiler features directly. PROTEL is considered 'wordy', containing a large number of reserved words with some statements reading like English. PROTEL source code is case insensitive but by convention upper case is used for reserved words. Variables and Assignment Most global and all local variables are declared using the DECL reserved word. Variables can be initialized using INIT keyword. Constants use IS keyword, hexadecimal uses #. Global variables can also use PROTECTED, or PRIVATE declarations to define write protected data or thread local data respectively. Writes to protected data requires the use of builtin primitives that alter protected data in a safe way. Protected data survives all restarts short of a system image reload. Note WRITE_PROTECTED_STORE arguments are type agnostic as long as the types of both arguments match. PRIVATE provides a private copy of the data for each process that uses it. There is no COW functionality, each process is allocated its own copy and optionally initializes it at creation. Note Local variables defined using DECL are naturally private. GAZINTA Gazinta is the colloquial name used for the assignment operator '->'. Its name comes from 'goes into' meaning expression gazinta (goes into) variable. Expressions are evaluated in strict left to right order with no operator precedence. Lack of operator precedence is a legacy of the NT40 processor which used a stack based ALU using RPN logic. Parentheses are used to prioritize subexpressions. Pointers The pointer operator is @ and is placed after the ptr. A NULL pointer is a predefined value that is guaranteed not to point to a mapped address. It is not 0 nor -1 nor another the predefined uninitialized memory pattern (#FDFD). In other words, a pointer is not NULL by default, it must be set in the code. Pointer arithmetic is not supported. Note Dereferencing a NULL pointer will cause a data access trap. Descriptors The descriptor 'DESC' is a compiler defined structure containing a pointer to an array and the array upperbound. A descriptorized array is indexed using simple array syntax 'MY_DESC[I]' and the UPB operator can be used to access the upperbound 'UPB MYDESC'. A TDSIZE operator also exists as a legacy of the descriptor implementation on NT40: TDSIZE = UPB+1. Descriptors have automatic run time bounds checking on dynamically allocated arrays. Indexing a descriptor out of bounds or indexing a NULL descriptor will cause a descriptor range check trap. UPB is generally used by application software to more gracefully handle index out of range. Note NULL can be used for pointers and descriptors. Strings use descriptors extensively. Strings are of a defined length with no NULL character terminator. Blocks Block scope is defined by BLOCK and ENDBLOCK statements, which are analogous to BEGIN END in Pascal or { } in C. Blocks can optionally be labeled for enhanced compiler checking and functionality. Procedures Procedures and functions are only differentiated by the presence of the RETURNS clause and the requirement to include a RETURN statement. A RETURN statement may be inserted anywhere in a function or procedure. Declaration Implementation Structures The TABLE is the basic array structure. TABLE is only used for arrays whose size is known at compile time. Descriptors are the preferred way to reference arrays. Indexing a table out of range will cause a table range check trap. UPB and TDSIZE operators also apply to tables. Unions The OVERLAY is the basic union structure. It is declared and used in a manner similar to Pascal-descended languages. AREAs Areas are memory blocks that could be cast to TABLES and OVERLAYS. They are declared in bytes and typically are declared large enough to allow for future expansion. This is due to the desire to upgrade DMS software 'live' without requiring a restart. The modular nature of PROTEL allows relatively small chunks of code to be swapped into a load; if AREAs were planned smartly, this would not affect the placement of modules in memory, thereby avoiding a restart. SUBSYSTEMs, MODULEs, and SECTIONs A SECTION is a text file containing source code and directives to manage the different section types and their position in the module hierarchy. A SECTION is the smallest unit of compilation. A MODULE is the smallest unit of linkage and loading and contains one or more sections. A SUBSYSTEM is the smallest unit of packaging and contains one or more modules. Control Flow There are 2 forms of the case (switch) statement. Using the CASE keyword uses a jump table and SELECT uses sequential if-then-else logic. Cases are exclusive, they don't fall through as in C. References |
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[SOURCE: https://en.wikipedia.org/wiki/Traditional_story] | [TOKENS: 5678] |
Contents Traditional story Traditional stories, or stories about traditions, differ from both fiction and nonfiction in that the importance of transmitting the story's worldview is generally understood to transcend an immediate need to establish its categorization as imaginary or factual. In the academic circles of literature, religion, history, and anthropology, categories of traditional story are important terminology to identify and interpret stories more precisely. Some stories belong in multiple categories and some stories do not fit into any category. Anecdote An anecdote is a short and amusing or interesting story about a biographical incident. It may be as brief as the setting and provocation of a bon mot. An anecdote is always presented as based on a real incident involving actual persons, whether famous or not, usually in an identifiable place; whether authentic or not, it has verisimilitude or truthiness. Over time, modification in reuse may convert a particular anecdote to a fictional piece, one that is retold but is "too good to be true". Sometimes humorous, anecdotes are not jokes, because their primary purpose is not simply to evoke laughter, but to reveal a truth more general than the brief tale itself, or to delineate an institutional or character trait in such a light that it strikes in a flash of insight to the very essence. Novalis observed, "An anecdote is a historical element — a historical molecule or epigram." A brief monologue beginning "A man pops in a bar ..." will be a joke. A brief monologue beginning "Once J. Edgar Hoover popped in a bar ..." will be an anecdote. An anecdote thus is closer to the tradition of the parable than the patently invented fable with its animal characters and generic human figures — but it is distinct from the parable in the historical specificity which it claims. Anecdotes are often of satirical nature. Under the totalitarian regime in the Soviet Union numerous political anecdotes circulating in society were the only way to reveal and denounce vices of the political system and its leaders. They made fun of such personalities as Lenin, Khrushchev, Brezhnev, and other Soviet leaders. In contemporary Russia there are many anecdotes about Vladimir Putin. The word 'anecdote' (in Greek: "unpublished", literally "not given out") comes from Procopius of Caesarea, the biographer of Justinian I, who produced a work entitled Ἀνέκδοτα (Anekdota, variously translated as Unpublished Memoirs or Secret History), which is primarily a collection of short incidents from the private life of the Byzantine court. Gradually, the term anecdote came to be applied[a] to any short tale utilized to emphasize or illustrate whatever point the author wished to make.[b] Apologue An apologue or apolog (from the Greek ἀπόλογος, a "statement" or "account") is a brief fable or allegorical story with pointed or exaggerated details, meant to serve as a pleasant vehicle for a moral doctrine or to convey a useful lesson without stating it explicitly. It is like a parable, except that it contains supernatural elements like a fable, often the personification of animals or plants. Unlike a fable, the moral is more important than the narrative details. As with the parable, the apologue is a tool of rhetorical argument used to convince or persuade. Among the best known ancient and classical examples are that of Jotham in the Book of Judges (9:7-15); "The Belly and its Members", by the patrician Agrippa Menenius Lanatus in the second book of Livy; and perhaps most famous of all, those of Aesop. Well-known modern examples of this literary form include George Orwell's Animal Farm and the Br'er Rabbit stories derived from African and Cherokee cultures and recorded and synthesized by Joel Chandler Harris. The term is applied more particularly to a story in which the actors or speakers are either various kinds of animals or are inanimate objects. An apologue is distinguished from a fable in that there is always some moral sense present in the former, which there need not be in the latter. An apologue is generally dramatic, and has been defined as "a satire in action." An apologue differs from a parable in several respects. A parable is equally an ingenious tale intended to correct manners, but it can be true in the sense that "when this kind of actual event happens among men, this is what it means and this is how we should think about it", while an apologue, with its introduction of animals and plants, to which it lends ideas, language and emotions, contains only metaphoric truth: "when this kind of situation exists anywhere in the world, here is an interesting truth about it." The parable reaches heights to which the apologue cannot aspire, for the points in which animals and nature present analogies to man are principally those of his lower nature (hunger, desire, pain, fear, etc.), and the lessons taught by the apologue seldom therefore reach beyond prudential morality (keep yourself safe, find ease where you can, plan for the future, do not misbehave or you'll eventually be caught and punished), whereas the parable aims at representing the relations between man and existence or higher powers (know your role in the universe, behave well towards all you encounter, kindness and respect are of higher value than cruelty and slander). It finds its framework in the world of nature as it actually is, and not in any parody of it, and it exhibits real and not fanciful analogies. The apologue seizes on that which humans have in common with other creatures, and the parable on that which we have in common with a greater existence. Still, in spite of the difference of moral level, Martin Luther thought so highly of apologues as counselors of virtue that he edited and revised Aesop and wrote a characteristic preface to the volume. The parable is always blunt and devoid of subtlety, and requires no interpretation; the apologue by nature necessitates at least some degree of reflection and thought to achieve understanding, and in this sense it demands more of the listener than the parable does. The origin of the apologue is extremely ancient and comes from the Middle East and its surrounding area (Persia, Asia Minor, Egypt, etc.), which is the Classical fatherland of everything connected with allegory, metaphor and imagination. Veiled truth was often necessary in the Middle East, particularly among the slaves, who dared not reveal their minds too openly. It is noteworthy that the two fathers of apologue in the West were slaves, namely Aesop and Phaedrus. La Fontaine in France; Gay and Dodsley in England; Gellert, Lessing and Hagedorn in Germany; Tomas de Iriarte in Spain, and Krylov in Russia, are leading modern writers of apologues. Length is not an essential matter in the definition of an apologue. Those of La Fontaine are often very short, as, for example, "Le Coq et la Perle" ("The Cock and the Pearl"). On the other hand, in the romances of Reynard the Fox we have medieval apologues arranged in cycles, and attaining epical dimensions. An Italian fabulist, Corti, is said to have developed an apologue of "The Talking Animals" reaching twenty-six cantos. La Motte, writing at a time when this species of literature was universally admired, attributes its popularity to the fact that it manages and flatters amour-propre by inculcating virtue in an amusing manner without seeming to dictate or insist. This was the ordinary 18th-century view of the matter, but Rousseau contested the educational value of instruction given in this indirect form. A work by P. Soullé, La Fontaine et ses devanciers (1866), is a history of the apologue from the earliest times until its final triumph in France. Montesquieu wrote a propos his Persian Letters "There are certain truths of which it is not enough to persuade, but which must be made to be felt. Such are the moral verities. Perhaps a bit of history will be more touching than subtle philosophy." Chivalric romance As a literary genre of high culture, romance or chivalric romance is a style of heroic prose and verse narrative that was popular in the aristocratic circles of High Medieval and Early Modern Europe. They were fantastic stories about marvel-filled adventures, often of a knight errant portrayed as having heroic qualities, who goes on a quest. Popular literature also drew on themes of romance, but with ironic, satiric or burlesque intent. Romances reworked legends, fairy tales, and history to suit the readers' and hearers' tastes, but by c.1600 they were out of fashion, and Miguel de Cervantes famously satirised them in his novel Don Quixote. Still, the modern image of "medieval" is more influenced by the romance than by any other medieval genre, and the word medieval invokes knights, distressed damsels, dragons, and other romantic tropes. Originally, romance literature was written in Old French, Anglo-Norman and Occitan, later, in English and German. During the early 13th century romances were increasingly written as prose. In later romances, particularly those of French origin, there is a marked tendency to emphasize themes of courtly love, such as faithfulness in adversity. During the Gothic Revival, from ca. 1800 the connotations of "romance" moved from the magical and fantastic to somewhat eerie "Gothic" adventure narratives. Creation myth A creation myth is a symbolic narrative of how the world began and how people first came to inhabit it. They develop in oral traditions and therefore typically have multiple versions; and they are the most common form of myth, found throughout human culture. In the society in which it is told, a creation myth is usually regarded as conveying profound truths, metaphorically, symbolically and sometimes even in a historical or literal sense. They are commonly, although not always, considered cosmogonical myths—that is they describe the ordering of the cosmos from a state of chaos or amorphousness. Creation myths often share a number of features. They often are considered sacred accounts and can be found in nearly all known religious traditions. They are all stories with a plot and characters who are either deities, human-like figures, or animals, who often speak and transform easily. They are often set in a dim and nonspecific past, what historian of religion Mircea Eliade termed in illo tempore ("at that time"). Also, all creation myths speak to deeply meaningful questions held by the society that shares them, revealing of their central worldview and the framework for the self-identity of the culture and individual in a universal context. Etiological myth An etiological myth, or origin myth, is a myth intended to explain the origins of cult practices, natural phenomena, proper names and the like, or create a mythic history for a place or family. For example, the name Delphi and its associated deity, Apollon Delphinios, are explained in the Homeric Hymn which tells of how Apollo carried Cretans over the sea in the shape of a dolphin (delphis) to make them his priests. While Delphi is actually related to the word delphus ("womb"), many etiological myths are similarly based on folk etymology (the term "Amazon", for example). In the Aeneid (published circa 17 BC), Vergil claims the descent of Augustus Caesar's Julian clan from the hero Aeneas through his son Ascanius, also called Iulus. The story of Prometheus' sacrifice-trick in Hesiod's Theogony relates how Prometheus tricked Zeus into choosing the bones and fat of the first sacrificial animal rather than the meat to justify why, after a sacrifice, the Greeks offered the bones wrapped in fat to the gods while keeping the meat for themselves. One type of origin myth is the creation myth (or cosmogonic myth), which describes the creation of the world. However, many cultures have stories set after the cosmogonic myth, which describe the origin of natural phenomena and human institutions within a preexisting universe. In Western classical scholarship, the word aition (from the Ancient Greek αἴτιον, "cause") is sometimes used for a myth that explains an origin, particularly how an object or custom came into existence. Fable A fable, as a literary genre, is a succinct fictional story, in prose or verse, that features animals, legendary creatures, plants, inanimate objects, or forces of nature that are anthropomorphised, and that illustrates a moral lesson (a "moral"), which may at the end be expressed explicitly in a pithy maxim. A fable differs from a parable in that the latter excludes animals, plants, inanimate objects, and forces of nature as actors that assume speech and other powers of humankind. Usage has not always been so clearly distinguished. In the King James Version of the New Testament, "μύθος" ("mythos") was rendered by the translators as "fable" in First and Second Timothy, in Titus and in First Peter. Factoid A factoid is a questionable or spurious (unverified, false, or fabricated) statement presented as a fact, but with no veracity. The word can also be used to describe a particularly insignificant or novel fact, in the absence of much relevant context. The word is defined by the Compact Oxford English Dictionary as "an item of unreliable information that is repeated so often that it becomes accepted as fact". Factoid was coined by Norman Mailer in his 1973 biography of Marilyn Monroe. Mailer described a factoid as "facts which have no existence before appearing in a magazine or newspaper", and created the word by combining the word fact and the ending -oid to mean "similar but not the same". The Washington Times described Mailer's new word as referring to "something that looks like a fact, could be a fact, but in fact is not a fact". Factoids may give rise to, or arise from, common misconceptions and urban legends. Fairy tale A fairy tale (pronounced /ˈfeəriˌteɪl/) is a type of short story that typically features folkloric fantasy characters, such as fairies, goblins, elves, trolls, dwarves, giants, mermaids or gnomes, and usually magic or enchantments. However, only a small number of the stories refer to fairies. The stories may nonetheless be distinguished from other folk narratives such as legends (which generally involve belief in the veracity of the events described) and explicitly moral tales, including beast fables. In less technical contexts, the term is also used to describe something blessed with unusual happiness, as in "fairy tale ending" (a happy ending) or "fairy tale romance" (though not all fairy tales end happily). Colloquially, a "fairy tale" or "fairy story" can also mean any far-fetched story or tall tale. In cultures where demons and witches are perceived as real, fairy tales may merge into legends, where the narrative is perceived both by teller and hearers as being grounded in historical truth. However, unlike legends and epics, they usually do not contain more than superficial references to religion and actual places, people, and events; they take place once upon a time rather than in actual times. Fairy tales are found in oral and in literary form. The history of the fairy tale is particularly difficult to trace because only the literary forms can survive. Still, the evidence of literary works at least indicates that fairy tales have existed for thousands of years, although not perhaps recognized as a genre; the name "fairy tale" was first ascribed to them by Madame d'Aulnoy in the late 17th century. Many of today's fairy tales have evolved from centuries-old stories that have appeared, with variations, in multiple cultures around the world. Fairy tales, and works derived from fairy tales, are still written today. The older fairy tales were intended for an audience of adults, as well as children, but they were associated with children as early as the writings of the précieuses; the Brothers Grimm titled their collection Children's and Household Tales, and the link with children has only grown stronger with time. Folklorists have classified fairy tales in various ways. The Aarne-Thompson classification system and the morphological analysis of Vladimir Propp are among the most notable. Other folklorists have interpreted the tales' significance, but no school has been definitively established for the meaning of the tales. A fairy tale with a tragic rather a happy ending is called anti-fairy tale. Folklore Folklore (or lore) consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales, stories, tall tales, and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called folkloristics. The word 'folklore' was first used by the English antiquarian William Thoms in a letter published in the London journal The Athenaeum in 1846. In usage, there is a continuum between folklore and mythology. Stith Thompson made a major attempt to index the motifs of both folklore and mythology, providing an outline into which new motifs can be placed, and scholars can keep track of all older motifs. Folklore can be divided into four areas of study: artifact (such as voodoo dolls), describable and transmissible entity (oral tradition), culture, and behavior (rituals). These areas do not stand alone, however, as often a particular item or element may fit into more than one of these areas. Folkloristics Folkloristics is the term preferred by academic folklorists[dubious – discuss] for the formal, academic discipline devoted to the study of folklore. The term itself derives from the nineteenth-century German designation folkloristik (i.e., folklore). Ultimately, the term folkloristics is used to distinguish between the materials studied, folklore, and the study of folklore, folkloristics. In scholarly usage, folkloristics represents an emphasis on the contemporary, social aspects of expressive culture, in contrast to the more literary or historical study of cultural texts. Ghost story A ghost story may be any piece of fiction, or drama, or an account of an experience, that includes a ghost, or simply takes as a premise the possibility of ghosts or characters' belief in them. Colloquially, the term can refer to any kind of scary story. In a narrower sense, the ghost story has been developed as a short story format, within genre fiction. It is a form of supernatural fiction and specifically of weird fiction, and is often a horror story. While ghost stories are often explicitly meant to be scary, they have been written to serve all sorts of purposes, from comedy to morality tales. Ghosts often appear in the narrative as sentinels or prophets of things to come. Whatever their uses, the ghost story is in some format present in all cultures around the world, and may be passed down orally or in written form. Joke A joke is something spoken, written, or done with humorous intention. Jokes may have many different forms, e.g., a single word or a gesture (considered in a particular context), a question-answer, or a whole short story. The word "joke" has a number of synonyms. To achieve their end, jokes may employ irony, sarcasm, word play and other devices. Jokes may have a punch line, i.e. an ending to make it humorous. A practical joke or prank differs from a spoken one in that the major component of the humour is physical rather than verbal (for example placing salt in the sugar bowl). Legend A legend (Latin, legenda, "things to be read") is a narrative of human actions that are perceived both by teller and listeners to take place within human history and to possess certain qualities that give the tale verisimilitude. Legend, for its active and passive participants includes no happenings that are outside the realm of "possibility", defined by a highly flexible set of parameters, which may include miracles that are perceived as actually having happened, within the specific tradition of indoctrination where the legend arises, and within which it may be transformed over time, in order to keep it fresh and vital, and realistic. The Brothers Grimm defined legend as folktale historically grounded. A modern folklorist's professional definition of legend was proposed by Timothy R. Tangherlini in 1990: Legend, typically, is a short (mono-) episodic, traditional, highly ecotypified[c] historicized narrative performed in a conversational mode, reflecting on a psychological level a symbolic representation of folk belief and collective experiences and serving as a reaffirmation of commonly held values of the group to whose tradition it belongs." Mythology The term mythology can refer either to the study of myths, or to a body or collection of myths. As examples, comparative mythology is the study of connections between myths from different cultures, whereas Greek mythology is the body of myths from ancient Greece. In the field of folkloristics, a myth is defined as a sacred narrative explaining how the world and humankind came to be in their present form and how customs, institutions and taboos were established. Many scholars in other fields use the term "myth" in somewhat different ways. In a very broad sense, the word can refer to any story originating within traditions. Oral tradition Oral tradition and oral lore is cultural material and tradition transmitted orally from one generation to another. The messages or testimony are verbally transmitted in speech or song and may take the form, for example, of folktales, sayings, ballads, songs, or chants. In this way, it is possible for a society to transmit oral history, oral literature, oral law and other knowledges across generations without a writing system. A narrower definition of oral tradition is sometimes appropriate. Sociologists might also emphasize a requirement that the material is held in common by a group of people, over several generations, and might distinguish oral tradition from testimony or oral history. In a general sense, "oral tradition" refers to the transmission of cultural material through vocal utterance, and was long held to be a key descriptor of folklore (a criterion no longer rigidly held by all folklorists). As an academic discipline, it refers both to a set of objects of study and a method by which they are studied—the method may be called variously "oral traditional theory", "the theory of Oral-Formulaic Composition" and the "Parry-Lord theory" (after two of its founders; see below) The study of oral tradition is distinct from the academic discipline of oral history, which is the recording of personal memories and histories of those who experienced historical eras or events. It is also distinct from the study of orality, which can be defined as thought and its verbal expression in societies where the technologies of literacy (especially writing and print) are unfamiliar to most of the population. Parable A parable is a succinct story, in prose or verse, that illustrates one or more moral, religious, instructive, or normative principles or lessons. It differs from a fable in that fables use animals, plants, inanimate objects, and forces of nature as actors that assume speech and other powers of humankind, while parables generally feature human characters. It is a type of analogy. Some scholars of the Canonical gospels and the New Testament apply the term "parable" only to the parables of Jesus, though that is not a common restriction of the term. Parables such as "The Prodigal Son" are central to Jesus' teaching method in both the canonical narratives and the apocrypha. Political myth A political myth is an ideological explanation for a political phenomenon that is believed by a social group. In 1975, Henry Tudor defined it in Political Myth published by Macmillan. He said A myth is an interpretation of what the myth-maker (rightly or wrongly) takes to be hard fact. It is a device men adopt in order to come to grips with reality; and we can tell that a given account is a myth, not by the amount of truth it contains, but by the fact that it is believed to be true, and above all, by the dramatic form into which it is cast ... What marks a myth as being political is its subject matter ... [P]olitical myths deal with politics ... A political myth is always the myth of a particular group. It has a hero or protagonist, not an individual, but a tribe, a nation, a race, a class ... [and] it is always the group which acts as the protagonist in a political myth. In 2001, Christopher G. Flood described a working definition of a political myth as an ideologically marked narrative which purports to give a true account of a set of past, present, or predicted political events and which is accepted as valid in its essentials by a social group. Tall tale A tall tale is a story with unbelievable elements, related as if it were true and factual. Some such stories are exaggerations of actual events, for example fish stories such as, "That fish was so big, why, I tell ya, it nearly sank the boat when I pulled it in!" Other tall tales are completely fictional tales set in a familiar setting, such as the European countryside, the American Old West, the Canadian Northwest, or the beginning of the Industrial Revolution. Tall tales are often told so as to make the narrator seem to have been a part of the story. They are usually humorous or good-natured. The line between myth and tall tale is distinguished primarily by age; many myths exaggerate the exploits of their heroes, but in tall tales the exaggeration looms large, to the extent of becoming the whole of the story. Urban legend An urban legend, urban myth, urban tale, or contemporary legend, is a form of modern folklore consisting of stories that may or may not have been believed by their tellers to be true. As with all folklore and mythology, the designation suggests nothing about the story's veracity, but merely that it is in circulation, exhibits variation over time, and carries some significance that motivates the community in preserving and propagating it. Despite its name, an urban legend does not necessarily originate in an urban area. Rather, the term is used to differentiate modern legend from traditional folklore in pre-industrial times. For this reason, sociologists and folklorists prefer the term contemporary legend. Urban legends are sometimes repeated in news stories and, in recent years, distributed by e-mail. People frequently allege that such tales happened to a "friend of a friend"; so often, in fact, that "friend of a friend" ("FOAF") has become a commonly used term when recounting this type of story. Some urban legends have passed through the years with only minor changes to suit regional variations. One example is the story of a woman killed by spiders nesting in her elaborate hairdo. More recent legends tend to reflect modern circumstances, like the story of people ambushed, anesthetized, and waking up minus one kidney, which was surgically removed for transplantation (a story which folklorists refer to as "The Kidney Heist"). Notes References External links |
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