YouTube is an American video-sharing website headquartered in San Bruno, California. Three former PayPal employees—Chad Hurley, Steve Chen, Jawed Karim—created the service in February 2005. Google bought the site in November 2006 for US$1.65 billion. YouTube allows users to upload, rate, add to playlists, comment on videos, subscribe to other users, it offers a wide variety of corporate media videos. Available content includes video clips, TV show clips, music videos and documentary films, audio recordings, movie trailers, live streams, other content such as video blogging, short original videos, educational videos. Most of the content on YouTube is uploaded by individuals, but media corporations including CBS, the BBC, Hulu offer some of their material via YouTube as part of the YouTube partnership program. Unregistered users can only watch videos on the site, while registered users are permitted to upload an unlimited number of videos and add comments to videos. Videos deemed inappropriate are available only to registered users affirming themselves to be at least 18 years old.
YouTube and its creators earn advertising revenue from Google AdSense, a program which targets ads according to site content and audience. The vast majority of its videos are free to view, but there are exceptions, including subscription-based premium channels, film rentals, as well as YouTube Music and YouTube Premium, subscription services offering premium and ad-free music streaming, ad-free access to all content, including exclusive content commissioned from notable personalities; as of February 2017, there were more than 400 hours of content uploaded to YouTube each minute, one billion hours of content being watched on YouTube every day. As of August 2018, the website is ranked as the second-most popular site in the world, according to Alexa Internet. YouTube has faced criticism over aspects of its operations, including its handling of copyrighted content contained within uploaded videos, its recommendation algorithms perpetuating videos that promote conspiracy theories and falsehoods, hosting videos ostensibly targeting children but containing violent and/or sexually suggestive content involving popular characters, videos of minors attracting pedophilic activities in their comment sections, fluctuating policies on the types of content, eligible to be monetized with advertising.
YouTube was founded by Chad Hurley, Steve Chen, Jawed Karim, who were all early employees of PayPal. Hurley had studied design at Indiana University of Pennsylvania, Chen and Karim studied computer science together at the University of Illinois at Urbana–Champaign. According to a story, repeated in the media and Chen developed the idea for YouTube during the early months of 2005, after they had experienced difficulty sharing videos, shot at a dinner party at Chen's apartment in San Francisco. Karim did not attend the party and denied that it had occurred, but Chen commented that the idea that YouTube was founded after a dinner party "was very strengthened by marketing ideas around creating a story, digestible". Karim said the inspiration for YouTube first came from Janet Jackson's role in the 2004 Super Bowl incident, when her breast was exposed during her performance, from the 2004 Indian Ocean tsunami. Karim could not find video clips of either event online, which led to the idea of a video sharing site.
Hurley and Chen said that the original idea for YouTube was a video version of an online dating service, had been influenced by the website Hot or Not. Difficulty in finding enough dating videos led to a change of plans, with the site's founders deciding to accept uploads of any type of video. YouTube began as a venture capital-funded technology startup from an $11.5 million investment by Sequoia Capital and an $8 million investment from Artis Capital Management between November 2005 and April 2006. YouTube's early headquarters were situated above a pizzeria and Japanese restaurant in San Mateo, California; the domain name www.youtube.com was activated on February 14, 2005, the website was developed over the subsequent months. The first YouTube video, titled Me at the zoo, shows co-founder Jawed Karim at the San Diego Zoo; the video was uploaded on April 23, 2005, can still be viewed on the site. YouTube offered the public a beta test of the site in May 2005; the first video to reach one million views was a Nike advertisement featuring Ronaldinho in November 2005.
Following a $3.5 million investment from Sequoia Capital in November, the site launched on December 15, 2005, by which time the site was receiving 8 million views a day. The site grew and, in July 2006, the company announced that more than 65,000 new videos were being uploaded every day, that the site was receiving 100 million video views per day. According to data published by market research company comScore, YouTube is the dominant provider of online video in the United States, with a market share of around 43% and more than 14 billion views of videos in May 2010. In May 2011, 48 hours of new videos were uploaded to the site every minute, which increased to 60 hours every minute in January 2012, 100 hours every minute in May 2013, 300 hours every minute in November 2014, 400 hours every minute in February 2017; as of January 2012, the site had 800 million unique users a month. It is estimated that in 2007 YouTube consumed as much bandwidth as the entire Internet in 2000. According to third-party web analytics providers and SimilarWeb, YouTube is the second-most visited website in the world, as of December 2016.
The Soviet Union the Union of Soviet Socialist Republics, was a socialist state in Eurasia that existed from 1922 to 1991. Nominally a union of multiple national Soviet republics, its government and economy were centralized; the country was a one-party state, governed by the Communist Party with Moscow as its capital in its largest republic, the Russian Soviet Federative Socialist Republic. Other major urban centres were Leningrad, Minsk, Alma-Ata, Novosibirsk, it spanned over 10,000 kilometres east to west across 11 time zones, over 7,200 kilometres north to south. It had five climate zones: tundra, steppes and mountains; the Soviet Union had its roots in the 1917 October Revolution, when the Bolsheviks, led by Vladimir Lenin, overthrew the Russian Provisional Government which had replaced Tsar Nicholas II during World War I. In 1922, the Soviet Union was formed by a treaty which legalized the unification of the Russian, Transcaucasian and Byelorussian republics that had occurred from 1918. Following Lenin's death in 1924 and a brief power struggle, Joseph Stalin came to power in the mid-1920s.
Stalin committed the state's ideology to Marxism–Leninism and constructed a command economy which led to a period of rapid industrialization and collectivization. During his rule, political paranoia fermented and the Great Purge removed Stalin's opponents within and outside of the party via arbitrary arrests and persecutions of many people, resulting in at least 600,000 deaths. In 1933, a major famine struck the country. Before the start of World War II in 1939, the Soviets signed the Molotov–Ribbentrop Pact, agreeing to non-aggression with Nazi Germany, after which the USSR invaded Poland on 17 September 1939. In June 1941, Germany broke the pact and invaded the Soviet Union, opening the largest and bloodiest theatre of war in history. Soviet war casualties accounted for the highest proportion of the conflict in the effort of acquiring the upper hand over Axis forces at intense battles such as Stalingrad and Kursk; the territories overtaken by the Red Army became satellite states of the Soviet Union.
The post-war division of Europe into capitalist and communist halves would lead to increased tensions with the United States-led Western Bloc, known as the Cold War. Stalin died in 1953 and was succeeded by Nikita Khrushchev, who in 1956 denounced Stalin and began the de-Stalinization; the Cuban Missile Crisis occurred during Khrushchev's rule, among the many factors that led to his downfall in 1964. In the early 1970s, there was a brief détente of relations with the United States, but tensions resumed with the Soviet–Afghan War in 1979. In 1985, the last Soviet premier, Mikhail Gorbachev, sought to reform and liberalize the economy through his policies of glasnost and perestroika, which caused political instability. In 1989, Soviet satellite states in Eastern Europe overthrew their respective communist governments; as part of an attempt to prevent the country's dissolution due to rising nationalist and separatist movements, a referendum was held in March 1991, boycotted by some republics, that resulted in a majority of participating citizens voting in favor of preserving the union as a renewed federation.
Gorbachev's power was diminished after Russian President Boris Yeltsin's high-profile role in facing down a coup d'état attempted by Communist Party hardliners. In late 1991, Gorbachev resigned and the Supreme Soviet of the Soviet Union met and formally dissolved the Soviet Union; the remaining 12 constituent republics emerged as independent post-Soviet states, with the Russian Federation—formerly the Russian SFSR—assuming the Soviet Union's rights and obligations and being recognized as the successor state. The Soviet Union was a powerhouse of many significant technological achievements and innovations of the 20th century, including the world's first human-made satellite, the first humans in space and the first probe to land on another planet, Venus; the country had the largest standing military in the world. The Soviet Union was recognized as one of the five nuclear weapons states and possessed the largest stockpile of weapons of mass destruction, it was a founding permanent member of the United Nations Security Council as well as a member of the Organization for Security and Co-operation in Europe, the World Federation of Trade Unions and the leading member of the Council for Mutual Economic Assistance and the Warsaw Pact.
The word "Soviet" is derived from a Russian word сове́т meaning council, advice, harmony and all deriving from the proto-Slavic verbal stem of vět-iti, related to Slavic věst, English "wise", the root in "ad-vis-or", or the Dutch weten. The word sovietnik means "councillor". A number of organizations in Russian history were called "council". For example, in the Russian Empire the State Council, which functioned from 1810 to 1917, was referred to as a Council of Ministers after the revolt of 1905. During the Georgian Affair, Vladimir Lenin envisioned an expression of Great Russian ethnic chauvinism by Joseph Stalin and his supporters, calling for these nation-states to join Russia as semi-independent parts of a greater union, which he named as the Union of Soviet Republics of Europe and Asia. Stalin resisted the proposal, but accepted it, although with Lenin's agreement changed the name of the newly proposed sta
Nuclear weapons testing
Nuclear weapons tests are experiments carried out to determine the effectiveness and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that developed nuclear weapons tested them. Testing nuclear weapons can yield information about how the weapons work, as well as how the weapons behave under various conditions and how personnel and equipment behave when subjected to nuclear explosions. Nuclear testing has been used as an indicator of scientific and military strength, many tests have been overtly political in their intention; the first nuclear device was detonated as a test by the United States at the Trinity site on July 16, 1945, with a yield equivalent to 20 kilotons of TNT. The first thermonuclear weapon technology test of an engineered device, codenamed "Ivy Mike", was tested at the Enewetak Atoll in the Marshall Islands on November 1, 1952 by the United States; the largest nuclear weapon tested was the "Tsar Bomba" of the Soviet Union at Novaya Zemlya on October 30, 1961, with the largest yield seen, an estimated 50–58 megatons.
In 1963, three of the four nuclear states and many non-nuclear states signed the Limited Test Ban Treaty, pledging to refrain from testing nuclear weapons in the atmosphere, underwater, or in outer space. The treaty permitted underground nuclear testing. France continued atmospheric testing until 1974, China continued until 1980. Neither has signed the treaty. Underground tests in the United States continued until 1992, the Soviet Union until 1990, the United Kingdom until 1991, both China and France until 1996. In signing the Comprehensive Nuclear-Test-Ban Treaty in 1996, these states have pledged to discontinue all nuclear testing. Non-signatories India and Pakistan last tested nuclear weapons in 1998. North Korea conducted nuclear tests in 2006, 2009, 2013, 2016, 2017; the most recent confirmed. Nuclear weapons tests have been divided into four categories reflecting the medium or location of the test. Atmospheric testing designates explosions; these have occurred as devices detonated on towers, barges, islands, or dropped from airplanes, those only buried far enough to intentionally create a surface-breaking crater.
The United States, the Soviet Union, China have all conducted tests involving explosions of missile-launched bombs. Nuclear explosions close enough to the ground to draw dirt and debris into their mushroom cloud can generate large amounts of nuclear fallout due to irradiation of the debris; this definition of atmospheric is used in the Limited Test Ban Treaty, which banned this class of testing along with exoatmospheric and underwater. Underground testing refers to nuclear tests conducted under the surface of the earth, at varying depths. Underground nuclear testing made up the majority of nuclear tests by the United States and the Soviet Union during the Cold War. True underground tests are intended to be contained and emit a negligible amount of fallout; these nuclear tests do "vent" to the surface, producing from nearly none to considerable amounts of radioactive debris as a consequence. Underground testing by definition, causes seismic activity of a magnitude that depends on the yield of the nuclear device and the composition of the medium in which it is detonated, creates a subsidence crater.
In 1976, the United States and the USSR agreed to limit the maximum yield of underground tests to 150 kt with the Threshold Test Ban Treaty. Underground testing falls into two physical categories: tunnel tests in horizontal tunnel drifts, shaft tests in vertically drilled holes. Exoatmospheric testing refers to nuclear tests conducted above the atmosphere; the test devices are lifted on rockets. These high altitude nuclear explosions can generate a nuclear electromagnetic pulse when they occur in the ionosphere, charged particles resulting from the blast can cross hemispheres following geomagnetic lines of force to create an auroral display. Underwater testing results from nuclear devices being detonated underwater moored to a ship or a barge. Tests of this nature have been conducted to evaluate the effects of nuclear weapons against naval vessels, or to evaluate potential sea-based nuclear weapons. Underwater tests close to the surface can disperse large amounts of radioactive particles in water and steam, contaminating nearby ships or structures, though they do not create fallout other than local to the explosion.
Another way to classify nuclear tests are by the number of explosions. The treaty definition of a salvo test is: In conformity with treaties between the United States and the Soviet Union, a salvo is defined, for multiple explosions for peaceful purposes, as two or more separate explosions where a period of time between successive individual explosions does not exceed 5 seconds and where the burial points of all explosive devices can be connected by segments of straight lines, each of them connecting two burial points, the total length does not exceed 40 kilometers. For nuclear weapon tests, a salvo is defined as two or more under
Nuclear warfare is a military conflict or political strategy in which nuclear weaponry is used to inflict damage on the enemy. Nuclear weapons are weapons of mass destruction. A major nuclear exchange would have long-term effects from the fallout released, could lead to a "nuclear winter" that could last for decades, centuries, or millennia after the initial attack; some analysts dismiss the nuclear winter hypothesis, calculate that with nuclear weapon stockpiles at Cold War highs, although there would be billions of casualties, billions more rural people would survive. However, others have argued that secondary effects of a nuclear holocaust, such as nuclear famine and societal collapse, would cause every human on Earth to starve to death. So far, two nuclear weapons have been used in the course of warfare, both by the United States near the end of World War II. On August 6, 1945, a uranium gun-type device was detonated over the Japanese city of Hiroshima. Three days on August 9, a plutonium implosion-type device was detonated over the Japanese city of Nagasaki.
These two bombings resulted in the deaths of 120,000 people. After World War II, nuclear weapons were developed by the Soviet Union, the United Kingdom and the People's Republic of China, which contributed to the state of conflict and extreme tension that became known as the Cold War. In 1974, in 1998, two countries that were hostile toward each other, developed nuclear weapons. Israel and North Korea are thought to have developed stocks of nuclear weapons, though it is not known how many; the Israeli government has never admitted or denied to having nuclear weapons, although it is known to have constructed the reactor and reprocessing plant necessary for building nuclear weapons. South Africa manufactured several complete nuclear weapons in the 1980s, but subsequently became the first country to voluntarily destroy their domestically made weapons stocks and abandon further production. Nuclear weapons have been detonated on over 2,000 occasions for testing demonstrations. After the collapse of the Soviet Union in 1991 and the resultant end of the Cold War, the threat of a major nuclear war between the two nuclear superpowers was thought to have declined.
Since concern over nuclear weapons has shifted to the prevention of localized nuclear conflicts resulting from nuclear proliferation, the threat of nuclear terrorism. The possibility of using nuclear weapons in war is divided into two subgroups, each with different effects and fought with different types of nuclear armaments; the first, a limited nuclear war, refers to a small-scale use of nuclear weapons by two belligerents. A "limited nuclear war" could include targeting military facilities—either as an attempt to pre-emptively cripple the enemy's ability to attack as a defensive measure, or as a prelude to an invasion by conventional forces, as an offensive measure; this term could apply to any small-scale use of nuclear weapons that may involve military or civilian targets. The second, a full-scale nuclear war, could consist of large numbers of nuclear weapons used in an attack aimed at an entire country, including military and civilian targets; such an attack would certainly destroy the entire economic and military infrastructure of the target nation, would have a devastating effect on Earth's biosphere.
Some Cold War strategists such as Henry Kissinger argued that a limited nuclear war could be possible between two armed superpowers. Some predict, that a limited war could "escalate" into a full-scale nuclear war. Others have called limited nuclear war "global nuclear holocaust in slow motion", arguing that—once such a war took place—others would be sure to follow over a period of decades rendering the planet uninhabitable in the same way that a "full-scale nuclear war" between superpowers would, only taking a much longer path to the same result; the most optimistic predictions of the effects of a major nuclear exchange foresee the death of many millions of victims within a short period of time. More pessimistic predictions argue that a full-scale nuclear war could bring about the extinction of the human race, or at least its near extinction, with only a small number of survivors and a reduced quality of life and life expectancy for centuries afterward. However, such predictions, assuming total war with nuclear arsenals at Cold War highs, have not been without criticism.
Such a horrific catastrophe as global nuclear warfare would certainly cause permanent damage to most complex life on the planet, its ecosystems, the global climate. If predictions about the production of a nuclear winter are accurate, it would change the balance of global power, with countries such as Australia, New Zealand, China and Brazil predicted to become world superpowers if the Cold War led to a large-scale nuclear attack. A study presented at the annual meeting of the American Geophysical Union in December 2006 asserted that a small-scale regional nuclear war could produce as many direct fatalities as all of World War II and disrupt the global climate for a decade or more. In a regional nuclear conflict scenario in w
Operation Plumbbob was a series of nuclear tests conducted between May 28 and October 7, 1957, at the Nevada Test Site, following Project 57, preceding Project 58/58A. It was the biggest and most controversial test series in the continental United States; the operation consisted of 29 explosions. Twenty-one laboratories and government agencies were involved. While most Operation Plumbbob tests contributed to the development of warheads for intercontinental and intermediate range missiles, they tested air defense and anti-submarine warheads with smaller yields, they included forty-three military effects tests on civil and military structures and bio-medical studies, aircraft structural tests. Operation Plumbbob had the tallest tower tests to date in the U. S. nuclear testing program as well as high-altitude balloon tests. One nuclear test involved the largest troop maneuver associated with U. S. nuclear testing. 18,000 members of the U. S. Air Force, Army and Marines participated in exercises Desert Rock VII and VIII during Operation Plumbbob.
The military was interested in knowing how the average foot-soldier would stand up, physically and psychologically, to the rigors of the tactical nuclear battlefield. 1,200 pigs were subjected to bio-medical experiments and blast-effects studies during Operation Plumbbob. On shot Priscilla, 719 pigs were used in various experiments on Frenchman Flat; some pigs were placed in elevated cages and provided with suits made of different materials, to test which materials provided best protection from the thermal radiation. As shown and reported in the PBS documentary Dark Circle, the pigs survived, but with third-degree burns to 80% of their bodies. Other pigs were placed in pens behind large sheets of glass at measured distances from the hypocenter to test the effects of flying debris on living targets. Studies were conducted of radioactive contamination and fallout from a simulated accidental detonation of a weapon. Nuclear weapons safety experiments were conducted to study the possibility of a nuclear weapon detonation during an accident.
On July 26, 1957, a safety experiment, Pascal-A, was detonated in an unstemmed hole at NTS, becoming the first underground shaft nuclear test. The knowledge gained here would provide data to prevent nuclear yields in case of accidental detonations—for example, in a plane crash; the John shot on July 19, 1957, was the only test of the Air Force's AIR-2 Genie missile with a nuclear warhead. It was fired from an F-89J Scorpion fighter over Yucca Flats at the NNSS. On the ground, the Air Force carried out a public relations event by having five Air Force officers and a photographer stand under ground zero of the blast, which took place at between 18,500 and 20,000 feet altitude, with the idea of demonstrating the possibility of the use of the weapon over civilian populations without ill effects. In 2012, the photographer and the last survivor of the five met in a restaurant in Dallas to reminisce; the five officers were: Colonel Sidney C. Bruce professor of Electrical Engineering at Colorado University, died in 2005.
Bodinger, died February 2, 1997. The photographer, Akira "George" Yoshitake, died in October 2013; the Rainier shot, conducted September 19, 1957, was the first contained underground nuclear test, meaning that no fission products were vented into the atmosphere. This test of 1.7 kt could be detected around the world by seismologists using ordinary seismic instruments. The Rainier test became the prototype for more powerful underground tests; some images from Upshot-Knothole Grable were accidentally relabeled as belonging to the Priscilla shot from Operation Plumbbob in 1957. As a consequence many publications including official government documents have the photo mislabeled. During the Pascal-B nuclear test, a 900-kilogram steel plate cap was blasted off the top of a test shaft at a speed of more than 66 km/s. Before the test, experimental designer Robert Brownlee had estimated that the nuclear explosion, combined with the specific design of the shaft, would accelerate the plate to six times Earth's escape velocity.
The plate was never found, but Dr. Brownlee believes that the plate did not leave the atmosphere, as it may have been vaporized by compression heating of the atmosphere due to its high speed; the calculated velocity was sufficiently interesting that the crew trained a high-speed camera on the plate, which only appeared in one frame, but this gave a high lower bound for its speed. After the event, Dr. Brownlee described the best estimate of the cover's speed from the photographic evidence as "going like a bat!" Lists of nuclear disasters and radioactive incidents Totskoye nuclear exercise Video clips: Historic color footage of shot "Owens", Rainier on YouTube during Operation Plumbbob Plumbbob page on the Nuclear Weapons Archive
Operation Tumbler–Snapper was a series of atomic tests conducted by the United States in early 1952 at the Nevada Test Site. The Tumbler-Snapper series of tests followed Operation Buster-Jangle, preceded Operation Ivy; the Tumbler phase, sponsored by the Atomic Energy Commission consisted of three airdrops which were intended to help explain discrepancies in the actual and estimated blast shock wave damage noted on previous detonations, to establish more the optimum height of burst. The Snapper phase, sponsored by the Department of Defense consisted of one airdrop and four tower shots intended to test various new weapons developments; the military exercise Desert Rock IV, involving 7350 soldiers, took place during the test series. They trained during the Charlie and George shots and observed shot Fox. "Troops shown three miles from'ground zero' of bomb" The short film Nuclear Test Film - Operation Tumbler-Snapper is available for free download at the Internet Archive The short film A-Bomb Blast Effects is available for free download at the Internet Archive Video clip: Historic footage of troops observing airdrop "Dog" from Camp Desert Rock