title: Radioisotope thermoelectric generator

text: Radioactive materials contained in RTGs are dangerous and can even be used for malicious purposes. They are barely useful for a genuine nuclear weapon, but still can serve in a "dirty bomb". The Soviet Union constructed many uncrewed lighthouses and navigation beacons powered by RTGs using strontium-90 (Sr). They are very reliable and provide a steady source of power. Most have no protection, not even fences or warning signs, and the locations of some of these facilities are no longer known due to poor record keeping. In one instance, the radioactive compartments were opened by a thief. In another case, three woodsmen in Tsalendzhikha Region, Georgia found two ceramic RTG orphan sources that had been stripped of their shielding; two of the woodsmen were later hospitalized with severe radiation burns after carrying the sources on their backs. The units were eventually recovered and isolated. There are approximately 1,000 such RTGs in Russia, all of which have long since exceeded their designed operational lives of ten years. Most of these RTGs likely no longer function, and may need to be dismantled. Some of their metal casings have been stripped by metal hunters, despite the risk of radioactive contamination. Transforming the radioactive material into an inert form reduces the danger of theft by people unaware of the radiation hazard (such as happened in the Goiânia accident in an abandoned Cs-137 source where the Caesium was present in easily water-soluble Caesium chloride form). However, a sufficiently chemically skilled malicious actor could extract a volatile species from inert material and/or achieve a similar effect of dispersion by physically grinding the inert matrix into a fine dust.


title: Radioisotope thermoelectric generator

text: RTGs pose a risk of radioactive contamination: if the container holding the fuel leaks, the radioactive material may contaminate the environment.


title: Radioisotope thermoelectric generator

text: For spacecraft, the main concern is that if an accident were to occur during launch or a subsequent passage of a spacecraft close to Earth, harmful material could be released into the atmosphere; therefore their use in spacecraft and elsewhere has attracted controversy.


title: Radioisotope thermoelectric generator

text: However, this event is not considered likely with current RTG cask designs. For instance, the environmental impact study for the Cassini–Huygens probe launched in 1997 estimated the probability of contamination accidents at various stages in the mission. The probability of an accident occurring which caused radioactive release from one or more of its three RTGs (or from its 129 radioisotope heater units) during the first 3.5 minutes following launch was estimated at 1 in 1,400; the chances of a release later in the ascent into orbit were 1 in 476; after that the likelihood of an accidental release fell off sharply to less than 1 in a million. If an accident which had the potential to cause contamination occurred during the launch phases (such as the spacecraft failing to reach orbit), the probability of contamination actually being caused by the RTGs was estimated at 1 in 10. The launch was successful and "Cassini–Huygens" reached Saturn.


title: Radioisotope thermoelectric generator

text: To minimize the risk of the radioactive material being released, the fuel is stored in individual modular units with their own heat shielding. They are surrounded by a layer of iridium metal and encased in high-strength graphite blocks. These two materials are corrosion- and heat-resistant. Surrounding the graphite blocks is an aeroshell, designed to protect the entire assembly against the heat of reentering the Earth's atmosphere. The plutonium fuel is also stored in a ceramic form that is heat-resistant, minimising the risk of vaporization and aerosolization. The ceramic is also highly insoluble.


title: Radioisotope thermoelectric generator

text: The plutonium-238 used in these RTGs has a half-life of 87.74 years, in contrast to the 24,110 year half-life of plutonium-239 used in nuclear weapons and reactors. A consequence of the shorter half-life is that plutonium-238 is about 275 times more radioactive than plutonium-239 (i.e. /g compared to /g). For instance, 3.6 kg of plutonium-238 undergoes the same number of radioactive decays per second as 1 tonne of plutonium-239. Since the morbidity of the two isotopes in terms of absorbed radioactivity is almost exactly the same, plutonium-238 is around 275 times more toxic by weight than plutonium-239.


title: Radioisotope thermoelectric generator

text: The alpha radiation emitted by either isotope will not penetrate the skin, but it can irradiate internal organs if plutonium is inhaled or ingested. Particularly at risk is the skeleton, the surface of which is likely to absorb the isotope, and the liver, where the isotope will collect and become concentrated.


title: Radioisotope thermoelectric generator

text: One RTG, the SNAP-19C, was lost near the top of Nanda Devi mountain in India in 1965 when it was stored in a rock formation near the top of the mountain in the face of a snowstorm before it could be installed to power a CIA remote automated station collecting telemetry from the Chinese rocket testing facility. The seven capsules were carried down the mountain onto a glacier by an avalanche and never recovered. It is most likely that they melted through the glacier and were pulverized, whereupon the plutonium zirconium alloy fuel oxidized soil particles that are moving in a plume under the glacier.


title: Radioisotope thermoelectric generator

text: Many Beta-M RTGs produced by the Soviet Union to power lighthouses and beacons have become orphaned sources of radiation. Several of these units have been illegally dismantled for scrap metal (resulting in the complete exposure of the Sr-90 source), fallen into the ocean, or have defective shielding due to poor design or physical damage. The US Department of Defense cooperative threat reduction program has expressed concern that material from the Beta-M RTGs can be used by terrorists to construct a dirty bomb. However, the Strontium titanate perovskite used is resistant to all likely forms of environmental degradation and cannot melt or dissolve in water. Bioaccumulation is unlikely as SrTiO passes through the digestive tract of humans or other animals unchanged, but the animal or human who ingested it would still receive a significant radiation dose to the sensitive intestinal lining during passage. Mechanical degradation of "pebbles" or larger objects into fine dust is more likely and could disperse the material over a wider area, however this would also reduce the risk of any single exposure event resulting in a high dose.


title: Radioisotope thermoelectric generator

text: Nuclear power reactors (including the miniaturized ones used in space) perform controlled nuclear fission in a chain reaction. The rate of the reaction can be controlled with neutron absorbing control rods, so power can be varied with demand or shut off (almost) entirely for maintenance. However, care is needed to avoid uncontrolled operation at dangerously high power levels, or even explosion or nuclear meltdown.


title: Radioisotope thermoelectric generator

text: Chain reactions do not occur in RTGs. Heat is produced through spontaneous radioactive decay at a non-adjustable and steadily decreasing rate that depends only on the amount of fuel isotope and its half-life. In an RTG, heat generation cannot be varied with demand or shut off when not needed and it is not possible to save more energy for later by reducing the power consumption. Therefore, auxiliary power supplies (such as rechargeable batteries) may be needed to meet peak demand, and adequate cooling must be provided at all times including the pre-launch and early flight phases of a space mission. While spectacular failures like a nuclear meltdown or explosion are impossible with an RTG, still there is a risk of radioactive contamination if the rocket explodes, or the device reenters the atmosphere and disintegrates.


title: Radioisotope thermoelectric generator

text: Due to the shortage of plutonium-238, a new kind of RTG assisted by subcritical reactions has been proposed. In this kind of RTG, the alpha decay from the radioisotope is also used in alpha-neutron reactions with a suitable element such as beryllium. This way a long-lived neutron source is produced. Because the system is working with a criticality close to but less than 1, i.e. K < 1, a subcritical multiplication is achieved which increases the neutron background and produces energy from fission reactions. Although the number of fissions produced in the RTG is very small (making their gamma radiation negligible), because each fission reaction releases over 30 times more energy than each alpha decay (200 MeV compared to 6 MeV), up to a 10% energy gain is attainable, which translates into a reduction of the Pu needed per mission. The idea was proposed to NASA in 2012 for the yearly NASA NSPIRE competition, which translated to Idaho National Laboratory at the Center for Space Nuclear Research (CSNR) in 2013 for studies of feasibility. However the essentials are unmodified.


title: Radioisotope thermoelectric generator

text: RTG have been proposed for use on realistic interstellar precursor missions and interstellar probes. An example of this is the Innovative Interstellar Explorer (2003–current) proposal from NASA.


title: Radioisotope thermoelectric generator

text: An RTG using Am was proposed for this type of mission in 2002. This could support mission extensions up to 1000 years on the interstellar probe, because the power output would decline more slowly over the long term than plutonium. Other isotopes for RTG were also examined in the study, looking at traits such as watt/gram, half-life, and decay products. An interstellar probe proposal from 1999 suggested using three advanced radioisotope power sources (ARPS).


title: Radioisotope thermoelectric generator

text: The RTG electricity can be used for powering scientific instruments and communication to Earth on the probes. One mission proposed using the electricity to power ion engines, calling this method radioisotope electric propulsion (REP).


title: Radioisotope thermoelectric generator

text: A power enhancement for radioisotope heat sources based on a self-induced electrostatic field has been proposed. According to the authors, enhancements of up to 10% could be attainable using beta sources.


title: Radioisotope thermoelectric generator

text: A typical RTG is powered by radioactive decay and features electricity from thermoelectric conversion, but for the sake of knowledge, some systems with some variations on that concept are included here.


title: Radioisotope thermoelectric generator

text: Known spacecraft/nuclear power systems and their fate. Systems face a variety of fates, for example, Apollo's SNAP-27 were left on the Moon. Some other spacecraft also have small radioisotope heaters, for example each of the Mars Exploration Rovers have a 1 watt radioisotope heater. Spacecraft use different amounts of material, for example MSL "Curiosity" has 4.8 kg of plutonium-238 dioxide, while the Cassini spacecraft had 32.7 kg.


title: Radioisotope thermoelectric generator

text: <nowiki>**</nowiki> not really an RTG, the BES-5 Buk () reactor was a fast breeder reactor which used thermocouples based on semiconductors to convert heat directly into electricity


title: Radioisotope thermoelectric generator

text: <nowiki>***</nowiki> not really an RTG, the SNAP-10A used enriched uranium fuel, zirconium hydride as a moderator, liquid sodium potassium alloy coolant, and was activated or deactivated with beryllium reflectors Reactor heat fed a thermoelectric conversion system for electrical production.


title: Radioisotope thermoelectric generator

text: <nowiki>****</nowiki> not really an RTG, the ASRG uses a Stirling power device that runs on radioisotope (see Stirling radioisotope generator)


title: Maggie Carey

text: Maggie Carey (born ) is an American film director, screenwriter, producer and actress. She has directed comedy shorts for television, and she wrote and directed the 2013 film "The To Do List".


title: Maggie Carey

text: Carey was raised in Boise, Idaho. She attended Jackson Elementary and West Junior High and graduated from Borah High School in 1993.


title: Maggie Carey

text: Of her high school experience, Carey said, "I was in every AP class possible. I played a ton of sports. I was in student council. I was an all-American soccer player." Carey was also a lifeguard at the Borah pool, an experience that would influence her film "The To-Do List".


title: Maggie Carey

text: Carey attended the University of Idaho for a year, before being recruited to the University of Montana to play Division I soccer in the team's inaugural season. She was co-captain of the team, making 26 appearances as a defender and scoring one goal. She graduated from Montana with a bachelor's degree in English literature. Carey went on to earn an MFA degree in film production from the University of Texas at Austin.


title: Maggie Carey

text: Carey was a member of New York's Upright Citizens Brigade improvisation troupe. Carey performed with both the Upright Citizens Brigade Theatre in New York and Improv Olympics West in Los Angeles.


title: Maggie Carey

text: In 2011, Carey cowrote and directed sketches for four episodes of "Funny or Die Presents" called "Lady Refs" about female referees working youth soccer games. Carey wrote and directed the low budget sex comedy, "The To Do List", which was released in 2013; the film is set in her home state of Idaho in 1993, featuring a lead character who is the same age as Carey was then.


title: Maggie Carey

text: Carey married actor Bill Hader in 2006. They had met in Los Angeles, California, through a friend of Carey's from college. They have three daughters together.


title: Maggie Carey

text: Hader and Carey separated in 2017. Hader filed for divorce in December of that year. They reached a divorce settlement in March 2018 and the divorce was finalized three months later.


title: Akula-class submarine

text: The Akula" class, Soviet designation Project 971 "Shchuka-B (, NATO reporting name Akula) are a series of fourth generation nuclear-powered attack submarines (SSNs) first deployed by the Soviet Navy in 1986. There are four sub-classes or flights of Shchuka-B, consisting of the original seven Project 971 boats (codenamed "Akula I"), commissioned between 1984 and 1990; six Project 971Is (Improved "Akula"s), commissioned between 1991 and 2009; one Project 971U ("Akula II"), commissioned in 1995; and one Project 971M ("Akula III"), commissioned in 2001. The Russians call all of the submarines "Shchuka-B", regardless of modifications.


title: Akula-class submarine

text: Some confusion may exist as the name "Akula" (, meaning "shark" in Russian) was used by the Soviets for a different class of submarines, the Project 941, which is known in the West as the . The Project 971 was named "Shchuka-B" by the Soviets but given the designation "Akula" by the West after the name of the lead ship, K-284.


title: Akula-class submarine

text: According to defence analyst Norman Polmar, the launch of the first submarine in 1985, "shook everyone [in the West] up", as Western intelligence agencies had not expected the Soviet Union to produce such a boat for another ten years.


title: Akula-class submarine

text: The "Akula" incorporates a double hull system composed of an inner pressure hull and an outer "light" hull. This allows more freedom in the design of the exterior hull shape, resulting in a submarine with more reserve buoyancy than its western analogs.


title: Akula-class submarine

text: The distinctive "bulb" or "can" located on top of the Akula's rudder houses its towed sonar array when retracted. Most "Akulas" have the wake detection system () (SOKS) hydrodynamic sensors, which detect changes in temperature and salinity. They are located on the leading edge of the sail, on the outer hull casing in front of the sail and on the bottom of the hull forward of the sail.


title: Akula-class submarine

text: "Akulas" (excluding "Nerpa") are armed with four 533 mm torpedo tubes which can use Type 53 torpedoes or the RPK-2, RPK-6 missile, and four 650 mm torpedo tubes which can use Type 65 torpedoes or the RPK-7 missile. These torpedo tubes are arranged in two rows of four tubes each. The external tubes are mounted outside the pressure hull in one row, above the torpedo tubes, and can only be reloaded in port or with the assistance of a submarine tender. The 650 mm tubes can be fitted with liners to use the 533 mm weaponry. The submarine is also able to use its torpedo tubes to deploy naval mines.


title: Akula-class submarine

text: As with many Soviet/Russian craft, information on the status of the Akula-class submarines is sparse, at best. Information provided by sources varies widely.


title: Akula-class submarine

text: Of the seven original "Akula"s, only three are known to still be in service. These boats are equipped with MGK-540 Skat-3 sonar system (NATO reporting name Shark Gill). The lead boat of the class, K-284 "Akula" was decommissioned in 2001, apparently to help save money in the cash-strapped Russian Navy. K-322 "Kashalot" and K-480 "Bars" [currently "Ak Bars"] are in reserve. K-480 "Bars" was put into reserve in 1998, and was being dismantled in February 2010. "Pantera" returned to service in January 2008 after a comprehensive overhaul. All were retrofitted with the SOKS hydrodynamic sensors. All submarines before K-391 "Bratsk" have reactor coolant scoops that are similar to the ones of the SSBNs, long and tubular. "Bratsk" and subsequent submarines have reactor coolant scoops similar to the short ones on the Oscar IIs (the "Typhoon", "Akula" and "Oscar" classes use the similar OK-650 reactor).


title: Akula-class submarine

text: The six "Akula"s of this class are all thought to be in service. They are quieter than the original "Akula"s. Sources also disagree as to whether construction of this class has been suspended, or if there are a further two units planned.


title: Akula-class submarine

text: Improved "Akula I" Hulls: K-328 "Leopard", K-461 "Volk", K-154 "Tigr", K-419 "Kuzbass", K-295 "Samara" and K-152 "Nerpa". These submarines are much quieter than early "Akula"-class submarines and all have the SOKS hydrodynamic sensors except "Leopard".


title: Akula-class submarine

text: K-157 "Vepr" is the only completed "Akula II" (see the table below). The "Akula II" is longer and displaces about 700 tons (submerged displacement) more than the "Akula I". The added space was used for additional quieting measures. K-157 "Vepr" became the first Russian submarine that was quieter than the latest U.S. attack submarines of that time, which was the improved (SSN 751 and later). Two of these submarines were used to build the SSBNs.


title: Akula-class submarine

text: The K-335 "Gepard" is the 14th submarine of the class and the only completed "Akula III" (see the table below) built for the Russian Navy. It was the first submarine commissioned in the Russian Navy since the "Kursk" disaster, as a result, its commissioning ceremony was an important morale boost for the Russian Navy with President Vladimir Putin in attendance. There is no NATO classification for the "Akula III". It is longer and has a larger displacement compared to the "Akula II", also it has an enlarged sail and a different towed-array dispenser on the vertical fin. Again, more noise reduction methods were employed. The "Gepard" was the most advanced Russian submarine before the submarines of the and class were commissioned.


title: Akula-class submarine

text: The Soviet advances in sound quieting were of considerable concern to the West, for acoustics was long considered the most significant advantage in U.S. submarine technology compared to the Soviets.


title: Akula-class submarine

text: In 1983–1984 the Japanese firm Toshiba sold sophisticated, nine axis milling equipment to the Soviets along with the computer control systems, which were developed by Norwegian firm Kongsberg Vaapenfabrik. U.S Navy officials and Congressmen announced that this technology enabled the Soviet submarine builders to produce more accurate and quieter propellers.


title: Akula-class submarine

text: The 1999–2000 edition of "Jane's Fighting Ships" incorrectly listed the first "Akula III" as "Viper" (the actual name is "Vepr", "wild boar" in Russian), commissioned on 25 November 1995. "Gepard" (Cheetah), was launched in 1999 and was commissioned 5 December 2001.


title: Akula-class submarine

text: Between December 1995 and February 1996, submarine "Volk" was deployed to the Mediterranean along the Russian aircraft carrier , where she monitored activities of several NATO submarines under Captain 1st rank S. V. Spravtsev.


title: Akula-class submarine

text: Between April and June 1996, "Tigr" was deployed in the Atlantic, where she detected a U.S. SSBN and tracked it on its combat patrol. On 23 July 1996, its commander, Captain 1st rank Alexey Burilichev, received a Hero of the Russian Federation award.


title: Akula-class submarine

text: In August 2009, the news media reported that two "Akula"-class submarines operated off the East Coast of the United States, with one of the submarines being identified as a Project 971 Shchuka-B type. U.S. military sources noted that this was the first known Russian submarine deployment to the western Atlantic since the end of the Cold War, raising concerns within U.S. military and intelligence communities. U.S. Northern Command confirmed that this 2009 "Akula"-class submarine deployment did occur. One of the boats was likely "Gepard" that finished a relatively lengthy combat patrol between June and September that year under the command of the Captain 1st rank Alexey Vyacheslavovich Dmitrov, who on 15 February 2012 was awarded a title Hero of the Russian Federation for courage shown at work. The other submarine could have been "Tigr" under the command of Captain E. A. Petrov, given that she performed a combat patrol sometime between March and November 2009. It is unlikely that other submarines of the project 971 could have been present in the Atlantic that year. "Pantera" was in Severemorsk during summer, while "Vepr", "Leopard" and "Volk" did not report any kind of activity in that year (1-3 submarines of the project are usually active with the Northern Fleet at any given moment).


title: Akula-class submarine

text: In August 2012, the news media reported that another "Akula"-class submarine operated in the Gulf of Mexico purportedly undetected for over a month, sparking controversy within U.S. military and political circles, with U.S. Senator John Cornyn of the Senate Armed Services Committee demanding details of this deployment from Admiral Jonathan W. Greenert, the Chief of Naval Operations. Most likely, this was "Tigr", as its commander Captain 1st rank Pavel Bulgakov received the Order of Courage on the Defender of the Fatherland Day on 22 February 2013.


title: Akula-class submarine

text: On 27 October 2008, it was reported that K-152 "Nerpa" of the Russian Pacific Fleet had begun her sea trials in the Sea of Japan before handover under a lease agreement to the Indian Navy. On 8 November 2008, while conducting one of these trials, an accidental activation of the halon-based fire-extinguishing system took place in the fore section of the vessel. Within seconds the halon gas had displaced all breathable air from the compartment. As a result, 20 people (17 civilians and 3 seamen) were killed by asphyxiation. Dozens of others suffered freon-related injuries and were evacuated to an unknown port in Primorsky Krai. This was the worst accident in the Russian navy since the loss of the submarine K-141 "Kursk" in 2000. The submarine itself did not sustain any serious damage and there was no release of radiation.


title: Akula-class submarine

text: Three hundred Indian Navy personnel were trained in Russia for the operation of the Akula II submarine "Nerpa". India has finalised a deal with Russia, in which at the end of the lease of these submarines, it has an option to buy them. The submarine is named INS "Chakra" as was the previous India-leased Soviet Charlie-I SSGN. "Chakra" was officially commissioned into the Indian Navy on 4 April 2012.


title: Akula-class submarine

text: Whereas the Russian Navy's Akula-II could be equipped with 28 nuclear-capable cruise missiles with a striking range of , the Indian version is reportedly armed with the -range Club-S nuclear-capable missiles. Missiles with ranges greater than cannot be exported due to arms control restrictions, since Russia is a signatory to the MTCR treaty.


title: Akula-class submarine

text: Russia said in December 2014 that it is ready to lease India more nuclear-powered submarines a day after President Vladimir Putin and Prime Minister Narendra Modi pledged to deepen defence ties.


title: Akula-class submarine

text: In January 2015, it was reported that India was involved in negotiations involving the leasing of the "Kashalot" and the "Iribis".


title: Akula-class submarine

text: On 7 March 2019, India and Russia signed a $3 billion deal for lease of another Akula-class nuclear-powered attack submarine. The submarine, dubbed as "Chakra III", should be delivered to the Indian Navy by 2025.


title: Akula-class submarine

text: In June 2021, "Nerpa" was reported in Singapore with Indian crew aboard and on its way back to Russia, despite one year remaining of the 10 year lease, commenced in April 2012. The stated reason was problems with maintenance of the nuclear reactors. Accordingly, the lease will not be prolonged after 2022, as initially expected.


title: Yuta Okkotsu

text: Akutami created Yuta alongside Rika before the creation of "Jujutsu Kaisen 0" as a duo who work together. He compared Yuta with the "Jujutsu Kaisen" protagonist Yuji Itadori, whose roles in the narratives are similar because having to deal with inner curses and have different personalities. In the 2021 animated film adaptation of the manga, "Jujutsu Kaisen 0", Yuta is voiced by Megumi Ogata in the Japanese version and Kayleigh McKee in the English version. Ogata's role was picked by Akutami himself, finding her ideal for the part, while McKee felt pressure over her work because of her lack of experience when the movie was dubbed as well as the tone needed.


title: Yuta Okkotsu

text: Yuta has met with positive response. some critics found him more appealing than the protagonist Yuji Itadori due to their different powers and backstories. His appearance in "Jujutsu Kaisen" also surprised critics due to his changed traits. Additionally, Yuta has been a popular character within the series, appearing in marketing and polls. Ogata's and McKee's performances of Yuta also drew positive responses in the media.


title: Yuta Okkotsu

text: Manga author Gege Akutami said Yuta and Rika were created as "a combo" for the story before he envisioned the manga's publication. The name sounded appealing to the author while was given for his kanji's meaning; "One With Many Friends", which the mangaka also liked. Akutami never intended his series "Tokyo Metropolitan Curse Technical School" to be serialized as it was Yuta's character arc was the focus of this short series. As a result, when "Jujutsu Kaisen" was created, Akutami replaced a new character, Yuji Itadori, in the leading role while Yuta became supporting. Similarities between Yuta and Itadori include their introduction to jujutsu, tragedy, naivety and having faced death. Despite their similarities, the two have been differentiated because "they carry themselves very differently ... Itadori is outgoing, where Yuta is more reserved".


title: Yuta Okkotsu

text: Yuta and Rika remained in the same form as in the final product. The concept of the story was creating sorcerers whou would be able to stop Yuta and Rika from killing others. Instead than Satoru Gojo, the character meant to recruit Yuta was Maki. Yuta's relatives were meant to be included into the story, most notably his sister who would be taken by Rika over jealousy. Although several changes were made until the official version, Akutami believes it should have kept the original concept. Yamanaka was interested by the storyboard and talked to other members from Shueisha about it. However, Akutami was stressed about expectations. In crafting the ideal protagonist, Akutami wanted Yuta to avoid being like himself. The first scene of Yuta being interrogated was influenced by the anime series "Neon Genesis Evangelion" which often uses a group known as SEELE that communicates with Gendo Ikari. Akutami included Michizane Sugawara, a famous figure in Japanese history, as an ancestor of Yuta and Gojo to explain their powers, as a tribute to the former editor Yamanaka. Akutami recounts that a scene where Yuta comforts his friend Maki surprised his editor Katayama; Katayama commented that Yuta understood Maki's feelings in their interactions. Akutami revised this scene in the storyboard following his editor's praise.


title: Yuta Okkotsu

text: In retrospect, Akutami found the early design of Yuta was too similar to that of fellow jujutsu sorcerer Megumi Fushiguro, who is recurring more in the main series to the point they might confuse readers. As a result, Akutami changed Yuta's look for the main series. For the series, Akutami teased readers with the possibility Yuta might have been romantically involved with another woman since Rika's death. Yuta's unique white uniform was made to reference problematic students but wears a black one in the final pages to fit with his classmates. Nevertheless, Akutami planned that once Yuta would return in "Jujutsu Kaisen", he would once again wear a white uniform in hopes older readers would remember him. When Akutami's father started reading his manga, the manga author started wondering he based on Yuta on his father or Megumi's father, Toji.


title: Yuta Okkotsu

text: Sunghoo Park, who directed the first season of the series' anime adaptation and prequel film, originally wanted to cover Yuta's story in the anime's first few episodes but later decided to begin the show with Yuji's introduction to the world of sorcerers and curses. In the original format, Park would dedicate the series' first three episodes to develop Yuji Itadori and then replace him with Okkotsu but the idea was scrapped. Although Yuta is not present in the anime's first season, he was given a brief cameo in the second introduction sequence, which was created months before the studio MAPPA confirmed the production of the "Jujutsu Kaisen 0" anime film.


title: Yuta Okkotsu

text: Park said that while Yuta and Rika are the main focus of the movie, he still wanted to explore more on his relationship with the supporting cast. Sunghoo Park cast Yuta's voice actor; Ogata's job surprised them because Yuta is a young male being voiced by a woman. In regards to the film's theme song King Gnu's , the lyrics places focus on the relationship between Yuta and Rika. Following the film's release, Park's favorite fight sequence is when Yuta calls Rika to Geto in terms of animation.


title: Yuta Okkotsu

text: Gege Akutami cast Megumi Ogata as Yuta's Japanese voice, following Park's advice and other staff members. The manga author claimed that the voice he envisioned was "neutral, soft, and kind, and there is also a big emotional swing and head". Ogata further said Yuta is one of the most relatable characters she has ever found due to the parallels she found when comparing his lonely childhood with hers and how both became sociable people. Additionally, she also found Yuta relatable because he continues suffering pain and overcomes his internal struggles.


title: Yuta Okkotsu

text: Ogata had to interact with the director Park to get a better understanding of him. With the help of Park and other staff members, Ogata managed to understand Yuta as a character. When the film premiered, Ogata said she was satisfied with her work and looked forward to her future projects. Fellow voice actors Yuichi Nakamura and Takahiro Sakurai felt that the feeling of "synchronization" is great in regards to Ogata's performance as Yuta. When asked about Ogata, Hanazawa commented through her work; she managed to feel Yuta's love through her partner's work, making the character loveable. In response to that, Ogata praised Hanazawa's work as Rika. In retrospect, Ogata said that voicing Yuta was a difficult work due to social distancing protocols.


title: Yuta Okkotsu

text: In the English dub, Yuta is voiced by Kayleigh McKee. McKee expressed satisfaction over being selected for Yuta's voice, calling the work "amazing, challenging, and so fun". McKee related to Yuta's lonely life during the curse and his eventual growth, which helped her find the pitch required to voice the character. She also found Yuta's story is similar to that a coming-of-age story due to his need to control the Rika while making friends. McKee, who was new to voice work, had fun doing fight scenes because her character makes several types pf sounds, especially because of Yuta's troubling experiences. McKee found the moments where Yuta calms down and makes touch with Rika as the most important for her because they show how kind he can be. Yuta's leading role in the movie made McKee nervous because she never had such a big role in her career.


title: Yuta Okkotsu

text: According to the website Real Sound, Yuta is the main focus of "Jujutsu Kaisen 0", whose narrative primarily focuses on his growth since Rika's death. Similarly, Polygon said the narrative's theme is Yuta's need to accept the death of Rika. Meanwhile, Anime News Network saw Yuta as an emotionally ambiguous character because of the way he deals with his feelings for Rika after her death. We Got This Covered Yuto stated it is a story focused on traumas, something the main series is known for. Park considers Yuta to be a straightforward teenager whose loneliness is caused by being chased by Rika's curse. While making the film, Megumi Ogata surprised Park by giving Yuta a sensitive characterization. The actress describes Yuta as an attractive character because he becomes stronger when interacting with others. Komatsu noted while at first Yuta appears to be weak, Ogata's performance helps give the character a stronger impression. Rika's curse is also considered the idea of how Yuta can use a major power for a great good. Early in the film, Rika defends Yuta from bullies, which causes him to distance himself from society. However, this instead causes Yuta to distance himself from society. The film expands upon Yuta's personal weaknesses, which are a result of an illness and his rejection of his surroundings. Yuta realizes he and his peers are both accepted through their interactions with one another. Yuta's reluctance to accept Rika's death parallels Yuji Itadori's need to accept his grandfather's death.


title: Yuta Okkotsu

text: In the series' beginning, Yuta finds salvation in Satoru Gojo, who guides him into controlling Rika in Jujutsu High and avoiding isolation. The Mary Sue said Yuta's growth makes him appealing because he stops wanting to kill himself and starts appreciating his life. Yuta's hero's journey advances through his physical growth; when Maki starts training him to stand alone, allowing him to turn into a hero. Despite his early passivity, Yuta shows a more aggressive personality when his friends are wounded by Suguru Geto, especially when the scene is animated. Fighting Geto and confronting Rika's curse allows Yuta to accept death and recover from the trauma of losing her. McKee was moved by Yuta's motivational speech about being cherished by his classmates and noted a major change of expression towards the climax in his fight against Geto.


title: Yuta Okkotsu

text: Satisfied with her role, McKee considered Yuta to have become more mature. Cullture agreed with McKee in regards to how Yuta is portrayed as a more composed teenager who in one year when compared with his original persona. He is noted to keep trust in his mentor Gojo. Additionally, Yuta is noted to share close connections with his former partners, mostly Maki, despite his absence. However, Cullture noted that there was no romance between them despite the tease made by Panda and Akutami himself.


title: Yuta Okkotsu

text: Yuta Okkotsu is the protagonist of "Tokyo Metropolitan Curse Technical School", retitled "Jujutsu Kaisen 0"; initially, he is a cursed victim of Special-Grade who is haunted by the spirit of his childhood friend Rika Orimoto. Satoru Gojo takes charge of Yuta's case and enrolls him at Tokyo Prefectural Jujutsu High School, where he befriends Panda, Maki Zen'in and Toge Inumaki. After training with Gojo and the other students, Yuta learns to control his cursed energy and becomes a skilled swordsman, often sparing with Maki. The power of Rika attracts Suguru Geto, a sorcerer who is friendly with Gojo but is antagonistic towards him. Geto attacks Yuta and his friends, severely wounding them.


title: Yuta Okkotsu

text: Enraged by his actions, Yuta unleashes Rika's curse, promising to join her if she helps him to defeat Geto. Yuta overwhelms Geto, who escapes after losing an arm in combat. As Gojo kills the escapees, it is revealed Rika did not curse Yuta, but after her death, Yuta's desire to make her survive resulted in him accidentally turning her into a curse demon. Now familiar with his powers, Yuta frees Rika, and she departs to the afterlife.


title: Yuta Okkotsu

text: In December 2021, Akutami wrote a new chapter based on "Jujutsu Kaisen 0". After Rika's passing, Yuta's group has part-time jobs in a store, where Utahime Iori is a customer.


title: Yuta Okkotsu

text: Yuta does not appear in the early chapters of "Jujutsu Kaisen", but Satoru Gojo mentions him as one of the upper-level students attending Jujutsu High who may one day surpass him when discussing students with Yuji Itadori. Upon his return to Japan, Yuta saves a child from a spirit surrounded by a replica he calls Rika. Yuta returns to Jujutsu High as an executioner of Yuji for possessing a vengeful spirit called Ryomen Sukuna after his mentor by also avenging his wounded friend Inumaki after an encounter with Sukuna. Yuta finds Yuji and his ally Choso are fighting with one of Maki's relatives, Naoya Zen'in. Yuta easily defeats Yuji and Choso and pretends to kill the former. After telling Naoya to inform their superiors that Yuji is dead, Yuta reveals himself as an ally to the recently revived Yuji upon Gojo's request to protect him. Yuta then reunites with Maki and other sorcerers to help Gojo and promises to kill Yuji if he can no longer control the vengeful spirit. The group joins forces to defeat Kenjaku, one of Suguru Geto's predecessors, who aims to curse Japanese civilians through his Culling Game terrorist attack.


title: Yuta Okkotsu

text: Yuta has been popular character within "Jujutsu Kaisen". In a Viz Media popularity poll conducted in March 2021, Yuta was voted as the eighth-most-popular character in the "Jujutsu Kaisen" franchise. In a second poll taken in December 2021 by "Shonen Jump", he was voted the eighth most popular character once again. To promote the series, Yuta's outfit was added to the NetEase video game "Knives Out" and a figurine of Yuta holding Rika was released by Shibuya Scramble Figure. Following the release of the "Jujutsu Kaisen 0" movie, Slashfilm listed the character as its third best character behind Rika and Panda. In May 2022, manga author Kenta Shinohara did his own tribute to the character of Yuta alongside Yuji and Megumi.


title: Yuta Okkotsu

text: Critics often praised Yuta's role in "Jujutsu Kaisen 0". Several writers enjoyed the handling of his story arc as well as his relationship with his classmates. Comic Book Resources called his story "perfect" for the movie adaptation. while Daryl Harding for Yatta-Tachi and Bleeding Cool found him an appealing character from the "shōnen" manga demography. Anime News Network and Comic Book Resources criticized Yuta's traits as a common trend in contrast due to his early growth Jacob Parker-Dalton from Otaquest said Yuta is a more interesting and more compelling character than the other lead, Yuji, who feels less active. In regards to his powers, "Los Angeles Times" compared the pairing of Yuta and Rika with that of the Marvel Comics character Venom because of the way Yuta has to control Rika's power in order to properly fight. On the other hand, Yuta was criticized for being overpowered due to Rika, making him less relatable. Nevertheless, the potential of power Yuta has was seen as promising because he is connected to the already powerful Satoru Gojo. The Digital Fix noted there are multiple differences between the two leads but found Yuta's story darker than Yuji's. Critics also praised Yuta's fight scenes in the movie, which were deemed superior to most of MAPPA's past works such as "The God of High School" with Polygon finding him comparable to the superhero Batman based on how energetic he becomes.


title: Yuta Okkotsu

text: Unlike the manga "Jujutsu Kaisen 0", the film adaptation includes a post-credits scene that foreshadows Yuta's inclusion in the main series, which IGN appreciated. Yuta's eventual return to "Jujutsu Kaisen" surprised critics due to the irony in the former protagonist's role of killing the current one. Comic Book Resources said Yuta's appearance in "Jujutsu Kaisen" was quite different from the original one upon his reveal. Despite the surprise the media got by this, Anime Hunch claimed that the entire fandom was relieved when Yuta was always acting based on Gojo's request to pretend to the higher ups that he kills Yuji, something noticeable by how his personality changes from aggressive in his fake demand to friendly and casual when he finds Yuji and continuously apologizes to him for wounding him. Sportskeeda came to regards Yuta as a more compelling protagonist that Yuji based on his likable personality as well as his fighting style which he manages to control on his own in contrast to Yuji is often the subject of Sukuna instead. The character's connection with the late Sugawara no Michizane was kept vague that might generate a future impact in the series by critics.


title: Yuta Okkotsu

text: There was also commentary about Yuta's voice actors in the "Jujutsu Kaisen 0" film. Some media praised Megumi Ogata's Japanese portrayal of Yuta for making the character stand out as unique in the film, in which when he changes from being calm, which was compared to her early deliveries as Shinji Ikari from "Neon Genesis Evangelion", to aggressive, when there are elements of horror and action. ANN and IGN also praised Yuta's relationship with Rika for giving him a less predictable characterization. Fandom Post compared Kayleigh McKee's voice work with that of Spike Spencer, who voiced Shinji in the English dub of the series, and wondered whether it was intentional. Hit equally praised McKee and Ogata for making Yuta more appealing alongside Rika. Pop Culture Maniac was more negative about McKee's work for making him sound childish rather than traumatized.


title: Kármán line

text: The Kármán line (or von Kármán line ) is an attempt to define a boundary between Earth's atmosphere and outer space, and offers a specific definition set by the Fédération aéronautique internationale (FAI), an international record-keeping body for aeronautics. Defining the edge of space is important for legal and regulatory purposes since aircraft and spacecraft fall under different jurisdictions and are subject to different treaties. International law does not define the edge of space, or the limit of national airspace.


title: Kármán line

text: The FAI defines the Kármán line as space beginning above Earth's mean sea level. This number is well above the altitude reachable by a conventional airplane and is roughly where satellites, even on very eccentric trajectories, will decay before completing a single orbit.


title: Kármán line

text: While experts disagree on exactly where the atmosphere ends and space begins, most regulatory agencies (including the United Nations) accept the FAI Kármán line definition or something close to it. As defined by the FAI, the Kármán line was established in the 1960s. Various countries and entities define space's boundary differently for various purposes.


title: Kármán line

text: The Kármán line is named after Theodore von Kármán (1881–1963), a Hungarian American engineer and physicist who was active in aeronautics and astronautics. In 1957, he was the first person to attempt to calculate an altitude limit for airplanes.


title: Kármán line

text: The expressions "edge of space" or ″near space″ are often used (by, for instance, the FAI in some of their publications) to refer to a region below the boundary of Outer Space, which is often meant to include substantially lower regions as well. Thus, certain balloon or airplane flights might be described as "reaching the edge of space". In such statements, "reaching the edge of space" merely refers to going higher than average aeronautical vehicles commonly would.


title: Kármán line

text: There is still no international legal definition of the demarcation between a country's air space and outer space. In 1963, Andrew G. Haley discussed the Kármán line in his book "Space Law and Government". In a chapter on the limits of national sovereignty, he made a survey of major writers' views. He indicated the inherent imprecision of the Line:


title: Kármán line

text: The line represents a mean or median measurement. It is comparable to such measures used in the law as mean sea level, meander line, tide line; but it is more complex than these. In arriving at the von Kármán jurisdictional line, myriad factors must be considered – other than the factor of aerodynamic lift. These factors have been discussed in a very large body of literature and by a score or more of commentators. They include the physical constitution of the air; the biological and physiological viability; and still other factors which logically join to establish a point at which air no longer exists and at which airspace ends.


title: Kármán line

text: Where space begins ... can actually be determined by the speed of the space vehicle and its altitude above the Earth. Consider, for instance, the record flight of Captain Iven Carl Kincheloe Jr. in an X-2 rocket plane. Kincheloe flew 2000 miles per hour (3,200 km/h) at 126,000 feet (38,500 m), or 24 miles up. At this altitude and speed, aerodynamic lift still carries 98 percent of the weight of the plane, and only two percent is carried by inertia, or Kepler force, as space scientists call it. But at 300,000 feet (91,440 m) or 57 miles up, this relationship is reversed because there is no longer any air to contribute lift: only inertia prevails. This is certainly a physical boundary, where aerodynamics stops and astronautics begins, and so I thought why should it not also be a jurisdictional boundary? Haley has kindly called it the Kármán Jurisdictional Line. Below this line, space belongs to each country. Above this level there would be free space.


title: Kármán line

text: An atmosphere does not abruptly end at any given height but becomes progressively less dense with altitude. Also, depending on how the various layers that make up the space around the Earth are defined (and depending on whether these layers are considered part of the actual atmosphere), the definition of the edge of space could vary considerably: If one were to consider the thermosphere and exosphere part of the atmosphere and not of space, one might have to extend the boundary to space to at least above sea level. The Kármán line thus is an arbitrary definition based on some technical considerations.


title: Kármán line

text: An aircraft can stay aloft only by constantly traveling forward relative to the air (rather than the ground), so that the wings can generate aerodynamic lift. The thinner the air, the faster the plane must go to generate enough lift to stay up. The amount of lift provided (which must equal the vehicle's weight in order to maintain level flight) is calculated by the lift equation:


title: Kármán line

text: Lift ("L") generated is directly proportional to the air density ("ρ"). An aircraft maintains altitude if the lift force equals the aircraft weight such that


title: Kármán line

text: where formula_3 is the aircraft mass, formula_4 is the acceleration due to gravity, and formula_5 is the downward force due to gravity (weight). All other factors remaining unchanged, true airspeed ("v") must increase to compensate for lower air density at higher altitudes.


title: Kármán line

text: At very high speeds, centrifugal force (Kepler force) given by formula_6, where formula_7 is the distance to the center of the Earth, contributes to maintaining altitude. This is the virtual force that keeps satellites in circular orbit without any aerodynamic lift. An aircraft can maintain altitude at the outer reaches of the atmosphere if the sum of the aerodymanic lift force and centrigugal force equals the aircraft weight.


title: Kármán line

text: As altitude increases and air density decreases, the speed to generate enough aerodynamic lift to support the aircraft weight increases until the speed becomes so high that the centrigual force contribution becomes significant. At a high enough altitude, the centrifugal force will dominate over the lift force and the aircraft would become effectively an orbiting spacecraft instead an aircraft supported by aerodynamic lift.


title: Kármán line

text: In 1956, von Kármán presented a paper in which he discussed aerothermal limits to flight. The faster aircraft fly, the more heat they would generate due to aerodynamic heating from friction with the atmosphere and adiabatic processes. Based on the current state of the art, he calculated the speeds and altitudes at which continuous flight was possible – fast enough that enough lift would be generated and slow enough that the vehicle would not overheat. The chart included an inflection point at around , above which the minimum speed would place the vehicle into orbit.


title: Kármán line

text: The term "Kármán line" was originally coined by Andrew G. Haley in a 1959 paper, based on von Kármán's 1956 paper, but Haley acknowledged that the limit was theoretical and would change as technology improved, as the minimum speed in von Kármán's calculations was based on the speed-to-weight ratio of current aircraft, namely the Bell X-2, and the maximum speed based on current cooling technologies and heat-resistant materials. Haley also cited other technical considerations for that altitude, as it was approximately the altitude limit for an airbreathing jet engine based on current technology. In the same 1959 paper, Haley also referred to as the "von Kármán Line", which was the lowest altitude at which free-radical atomic oxygen occurred.


title: Kármán line

text: The U.S. Armed Forces definition of an astronaut is a person who has flown higher than above mean sea level, approximately the line between the mesosphere and the thermosphere. NASA formerly used the FAI's figure, though this was changed in 2005, to eliminate any inconsistency between military personnel and civilians flying in the same vehicle, when three veteran NASA X-15 pilots (John B. McKay, William H. Dana and Joseph Albert Walker) were retroactively (two posthumously) awarded their astronaut wings, as they had flown between and in the 1960s, but at the time had not been recognized as astronauts. The latter altitude, achieved twice by Walker, exceeds the modern international definition of the boundary of space.


title: Kármán line

text: Works by Jonathan McDowell (Harvard-Smithsonian Center for Astrophysics) and Thomas Gangale (University of Nebraska-Lincoln) in 2018 advocate that the demarcation of space should be at , citing as evidence von Kármán's original notes and calculations (which concluded the boundary should be 270,000 ft), confirmation that orbiting objects can survive multiple perigees at altitudes around 80 to 90 km, plus functional, cultural, physical, technological, mathematical, and historical factors. More precisely, the paper summarizes:


title: Kármán line

text: These findings prompted the FAI to propose holding a joint conference with the International Astronautical Federation (IAF) in 2019 to "fully explore" the issue.


title: Kármán line

text: Another definition proposed in international law discussions defines the lower boundary of space as the lowest perigee attainable by an orbiting space vehicle, but does not specify an altitude. This is the definition adopted by the U.S. military. Due to atmospheric drag, the lowest altitude at which an object in a circular orbit can complete at least one full revolution without propulsion is approximately , whereas an object can maintain an elliptical orbit with perigee as low as about without propulsion. The U.S. is resisting regulatory movement on this front.


title: Kármán line

text: A key consideration is the concept of free molecular flow. The essential property of outer space is in its being a realm where there is significant space between molecules –hence the name. Under free molecular flow, the path of molecules has transitioned to being straight lines, no longer continually bouncing off of each other. This condition of space can be artificially created in a vacuum chamber, or happens naturally at a high enough altitude. It has been known since at least as early as 1964 that the transition to free molecular flow happens at an altitude above “75–80 km”. So the USAF and NASA definitions are supported by this scientifically significant data that the realm of space is entered after the molecules in the atmosphere move in straight lines under free molecular flow, above 80 km (50 miles).


title: Kármán line

text: While the Kármán line is defined for Earth only, if calculated for Mars and Venus it would be around and high respectively.


title: Ahad Raza Mir

text: Ahad Raza Mir (; born 29 September 1993) is a Pakistani actor who appears in Urdu television series. He has established a career in Pakistan and is the recipient of several awards including Lux Style Awards.


title: Ahad Raza Mir

text: Mir earned recognition with the television series "Sammi" (2017), and in the romantic drama "Yaqeen Ka Safar" which proved to be a breakthrough for him, earning him critical acclaim and a Lux Style Award for Best Actor.


title: Ahad Raza Mir

text: On 6 June 2019, Mir got engaged to actress Sajal Aly, and married her in a private intimate ceremony on 14 March 2020 in Abu Dhabi.


title: Ahad Raza Mir

text: In March 2022, there were speculations that the couple had parted ways after Sajal Aly reverted her name on Instagram. A couple of days later Aamna Ishani, a famous Pakistani journalist, confirmed that the couple were officially divorced.


title: Ahad Raza Mir

text: Ahad Raza Mir was born on 29 September 1993 in Karachi, Sindh, Pakistan. He is the son of Asif Raza Mir, a veteran actor and producer of the Pakistani film and television industry. Mir's paternal grandfather, Raza Mir, was a filmmaker who also served as cinematographer for the first ever Pakistani film, "Teri Yaad" (1948). He has a younger brother, Adnan Raza Mir. Mir attended a Performing Arts High School, and graduated from the University of Calgary with a Bachelor of Fine Arts degree.


title: Ahad Raza Mir

text: Mir started his career in 2010 at age 17, playing a brief role as the son of Sania Saeed and Faisal Rehman in the Hum TV's romantic drama "Khamosiyan". Mir started his career on stage, performing, directing and writing in several musicals and plays across Canada. Mir wanted to move to Toronto, but instead decided to go back to Pakistan to work in films and television.


title: Ahad Raza Mir

text: In 2017, Mir started auditioning for Hum TV's production house MD Productions, and was cast as a leading role in "Yaqeen Ka Safar" where he played Dr. Asfand Yaar, a grief-stricken brother alongside Sajal Aly and Hira Mani. He then had a supporting role in the social drama "Sammi" opposite Mawra Hocane. His performance earned him Lux Style Award for Best Actor, and won three Hum Awards including the Hum Award for Best Actor.


title: Ahad Raza Mir

text: Coming from an influential filmmaking family, Ahad was accused of nepotism. Responding to such claims Mir stated that he wanted “people to take [him],as an actor, very seriously and that he is “here to give Pakistan some good cinema and TV”.


title: Ahad Raza Mir

text: In 2018 Mir made his "Coke Studio" debut as a featured artist in its eleventh-season, where he performed the song "Ko Ko Korina" with Momina Mustehsan. Their rendition of the classic song was widely criticized. Within a few days of the video being released on YouTube, it became the most-disliked video in the music show's history.


title: Ahad Raza Mir

text: That same year, Mir made his film debut with Haseeb Hassan's military-drama "Parwaaz Hay Junoon", co-starring Hamza Ali Abbasi and Hania Amir, which was released on Eid al-Adha. Mir replaced Osman Khalid Butt in a role of Flight Lieutenant Saad, who opted out due to his other commitments.


title: Ahad Raza Mir

text: In 2018 Mir reunited with Sajal Aly and Mawra Hocane in Hum TV's Mohammed Ehteshamuddin-directed period drama "Aangan" where he played a poet, Jameel.


title: Ahad Raza Mir

text: In 2019, The Shakespeare Company,in a joint production with Vertigo Theatre in Canada, signed Mir to play Hamlet in their production becoming one of the first South Asian actor to play the role professionally in Canada. His performance won him the Betty Mitchell Award for Outstanding Performance by an Actor in a Drama.


title: Ahad Raza Mir

text: Mir became an executive producer for the upcoming movie "Kalasha", revolving around the culture of the Kalash people of the Chitral Valley.


title: Kaleidoscope

text: A kaleidoscope () is an optical instrument with two or more reflecting surfaces (or mirrors) tilted to each other at an angle, so that one or more (parts of) objects on one end of these mirrors are shown as a regular symmetrical pattern when viewed from the other end, due to repeated reflection. These reflectors are usually enclosed in a tube, often containing on one end a cell with loose, colored pieces of glass or other transparent (and/or opaque) materials to be reflected into the viewed pattern. Rotation of the cell causes motion of the materials, resulting in an ever-changing view being presented.


title: Kaleidoscope

text: Coined by its Scottish inventor David Brewster, "kaleidoscope" is derived from the Ancient Greek word καλός ("kalos"), "beautiful, beauty", εἶδος ("eidos"), "that which is seen: form, shape" and σκοπέω ("skopeō"), "to look to, to examine", hence "observation of beautiful forms." It was first published in the patent that was granted on July 10, 1817.


title: Kaleidoscope

text: Multiple reflection by two or more reflecting surfaces has been known since antiquity and was described as such by Giambattista della Porta in his "Magia Naturalis" (1558–1589). In 1646, Athanasius Kircher described an experiment with a construction of two mirrors, which could be opened and closed like a book and positioned in various angles, showing regular polygon figures consisting of reflected aliquot sectors of 360°. Mr. Bradley's "New Improvements in Planting and Gardening" (1717) described a similar construction to be placed on geometrical drawings to show an image with multiplied reflection. However, an optimal configuration that produces the full effects of the kaleidoscope was not recorded before 1815.


title: Kaleidoscope

text: In 1814, Sir David Brewster conducted experiments on light polarization by successive reflections between plates of glass and first noted "the circular arrangement of the images of a candle round a center, and the multiplication of the sectors formed by the extremities of the plates of glass". He forgot about it, but noticed a more impressive version of the effect during further experiments in February 1815. A while later he was impressed by the multiplied reflection of a bit of cement that was pressed through at the end of a triangular glass trough, which appeared more regular and almost perfectly symmetrical in comparison to the reflected objects that had been situated further away from the reflecting plates in earlier experiments. This triggered more experiments to find the conditions for the most beautiful and symmetrically perfect conditions. An early version had pieces of colored glass and other irregular objects fixed permanently and was admired by some Members of the Royal Society of Edinburgh, including Sir George Mackenzie who predicted its popularity. A version followed in which some of the objects and pieces of glass could move when the tube was rotated. The last step, regarded as most important by Brewster, was to place the reflecting panes in a draw tube with a concave lens to distinctly introduce surrounding objects into the reflected pattern.


title: Kaleidoscope

text: Brewster thought his instrument to be of great value in "all the ornamental arts" as a device that creates an "infinity of patterns". Artists could accurately delineate the produced figures of the kaleidoscope by means of the solar microscope (a type of camera obscura device), magic lantern or camera lucida. Brewster believed it would at the same time become a popular instrument "for the purposes of rational amusement". He decided to apply for a patent. British patent no. 4136 "for a new Optical Instrument called "The Kaleidoscope" for exhibiting and creating beautiful Forms and Patterns of great use in all the ornamental Arts" was granted in July 1817. Unfortunately the manufacturer originally engaged to produce the product had shown one of the patent instruments to some of the London opticians to see if he could get orders from them. Soon the instrument was copied and marketed before the manufacturer had prepared any number of kaleidoscopes for sale. An estimated two hundred thousand kaleidoscopes sold in London and Paris in just three months. Brewster figured at most a thousand of these were authorized copies that were constructed correctly, while the majority of the others did not give a correct impression of his invention. Because so relatively few people had experienced a proper kaleidoscope or knew how to apply it to ornamental arts, he decided to publicize a treatise on the principles and the correct construction of the kaleidoscope.


title: Kaleidoscope

text: It was thought that the patent was reduced in a Court of Law since its principles were supposedly already known. Brewster stated that the kaleidoscope was different because the particular positions of the object and of the eye, played a very important role in producing the beautiful symmetrical forms. Brewster's opinion was shared by several scientists, including James Watt.


title: Kaleidoscope

text: Philip Carpenter originally tried to produce his own imitation of the kaleidoscope, but was not satisfied with the results. He decided to offer his services to Brewster as manufacturer. Brewster agreed and Carpenter's models were stamped "sole maker". Realizing that the company could not meet the level of demand, Brewster gained permission from Carpenter in 1818 for the device to be made by other manufacturers. In his 1819 "Treatise on the Kaleidoscope" Brewster listed more than a dozen manufacturers/sellers of patent kaleidoscopes. Carpenter's company would keep on selling kaleidoscopes for 60 years.


title: Kaleidoscope

text: In 1987, kaleidoscope artist Thea Marshall, working with the Willamette Science and Technology Center, a science museum located in the Eugene, Oregon, designed and constructed a 1,000 square foot traveling mathematics and science exhibition, "Kaleidoscopes: Reflections of Science and Art." With funding from the National Science Foundation, and circulated under the auspices of the Smithsonian Institution Traveling Exhibition Service (SITES), the exhibition appeared in 15 science museums over a three-year period, reaching more than one million visitors in the United States and Canada. Interactive exhibit modules enabled visitors to better understand and appreciate how kaleidoscopes function.


title: Kaleidoscope

text: Manufacturers and artists have created kaleidoscopes with a wide variety of materials and in many shapes. A few of these added elements that were not previously described by inventor David Brewster:


title: Kaleidoscope

text: Cozy Baker (d. October 19, 2010)—founder of the Brewster Kaleidoscope Society—collected kaleidoscopes and wrote books about many of the artists making them in the 1970s through 2001. Her book "Kaleidoscope Artistry" is a limited compendium of kaleidoscope makers, containing pictures of the interior and exterior views of contemporary artworks. Baker is credited with energizing a renaissance in kaleidoscope-making in the US; she spent her life putting kaleidoscope artists and galleries together so they would know each other and encourage each other.


title: Kaleidoscope

text: In 1999 a short-lived magazine dedicated to kaleidoscopes—"Kaleidoscope Review"—was published, covering artists, collectors, dealers, events, and including how-to articles. This magazine was created and edited by Brett Bensley, at that time a well-known kaleidoscope artist and resource on kaleidoscope information. Changed name to "The New Kaleidoscope Review", and then switched to a video presentation on YouTube, "The Kaleidoscope Maker."


title: Kaleidoscope

text: Most kaleidoscopes are mass-produced from inexpensive materials, and intended as children's toys. At the other extreme are handmade pieces that display fine craftsmanship. Craft galleries often carry a few kaleidoscopes, while other enterprises specialize in them, carrying dozens of different types from different artists and craftspeople. Most handmade kaleidoscopes are now made in India, Bangladesh, Japan, the US, Russia and Italy, following a long tradition of glass craftsmanship in those countries.


title: Catherine McCormack

text: Catherine Jane McCormack (born 3 April 1972) is an English actress of stage and screen. Her film appearances include "Braveheart" (1995), "The Land Girls" (1998), "Dangerous Beauty" (1998), "Dancing at Lughnasa" (1998), "Spy Game" (2001), and "28 Weeks Later" (2007). Her theatre work includes National Theatre productions of "All My Sons" (2000) and "Honour" (2003).


title: Catherine McCormack

text: McCormack was born in Epsom, Surrey, England. She is of part Irish ancestry as one of her grandfathers was Irish. Her mother died of lupus when McCormack was six years old and her steelworker father subsequently raised her and her brother Stephen. She was brought up as Roman Catholic and attended the Convent of Our Lady of Providence. She went on to study at the Oxford School of Drama.


title: Catherine McCormack

text: McCormack's first important role was as the character Murron MacClannough in the multiple Academy Award-winning film "Braveheart" (1995). Her screen debut was as the lead in the Anna Campion-directed film "Loaded" (1994). She has subsequently stated that she had a "miserable time with the director (Anna Campion)... it was my first film job, I needed to be mollycoddled, I needed to be helped through it, and I wasn't. Mostly, it was a horrible experience."


title: Catherine McCormack

text: After "Braveheart", McCormack starred alongside Anna Friel and Rachel Weisz in David Leland's "The Land Girls" and had lead roles in Nils Gaup's "Northstar" and Marshall Herskovitz's "Dangerous Beauty". Other films include "Spy Game" (2001) and "28 Weeks Later". Despite being in demand, she does few films, stating that "I read very few scripts I'm passionate about... Maybe one in every twenty or thirty."


title: Catherine McCormack

text: McCormack has shown a preference in her career for the theatre, saying that "theatre really is an actor's medium: you're on stage with no director anymore, whereas in film very rarely do you get much rehearsal other than running through the scene very quickly. Then everyone comes in and shoots it." McCormack was one of the original 2006 London cast of Patrick Barlow's play of "The 39 Steps". In 2008, she performed the role of Nora in "A Doll's House", directed by Peter Hall at the Theatre Royal, Bath, and also the role of Isabel Archer in a stage adaptation of "The Portrait of a Lady", both of which commenced their runs in July 2008, ending in August, before transferring to the Rose Theatre in Kingston later that year.


title: Catherine McCormack

text: In 2009, she appeared in the British tour of Headlong's adaptation of "Six Characters in Search of an Author". In 2012, she starred as Juana Inés de la Cruz in the Royal Shakespeare Company's production of Helen Edmundson's play "The Heresy of Love".


title: Dolby Theatre

text: The Dolby Theatre (formerly known as the Kodak Theatre) is a live-performance auditorium in the Ovation Hollywood shopping mall and entertainment complex, on Hollywood Boulevard and Highland Avenue, in the Hollywood district of Los Angeles. Since its opening on November 9, 2001, it has been the venue of the annual Academy Awards ceremony. It is adjacent to Grauman's Chinese Theatre and near the El Capitan Theatre on Hollywood Boulevard.


title: Dolby Theatre

text: The theater was designed by David Rockwell of the Rockwell Group specifically with the Oscar ceremonies in mind. Though the stage is one of the largest in the United States—roughly tied with the Elliott Hall of Music at Purdue University—measuring wide and deep, its seating capacity is only about half that of the Hall of Music, accommodating 3,332 people.


title: Dolby Theatre

text: The auditorium has become known as a venue for televised theatrical performances (e.g., "American Idol" and the Academy Awards). The architectural team consulted extensively with leading production personnel in Hollywood, achieving a highly functional cable infrastructure, with an underground cable bunker that crosses under the theater to truck locations on adjacent streets. Power is also substantial and accessible. The theater has a unique Rockwell-designed cockpit in the orchestra seating area for camera, sound, and stage management.


title: Dolby Theatre

text: The hall from the front entrance to the grand stairway (leading up to the theater at the rear of the shopping complex) is flanked by storefronts, as well as Art Deco columns displaying the names of past recipients of the Academy Award for Best Picture (with blank spaces left for future Best Picture winners, currently set up to 2071). In a fashion reminiscent of Hollywood movie-making, the building is dressed before the Academy Awards ceremony, sometimes with a different sign on its façade, red drapery to hide its storefronts, and the famous red carpet running up its grand stairway.


title: Dolby Theatre

text: The theater was developed by the Academy of Motion Picture Arts and Sciences (AMPAS) to overcome logistical issues it faced hosting the Academy Awards at other venues, such as the Dorothy Chandler Pavilion and Shrine Auditorium. In August 1997, AMPAS and Canadian development firm TrizecHahn went into negotiations over the development of an entertainment complex located on the corner of Hollywood Boulevard and Highland Avenue adjacent to the Mann's Chinese Theatre. Seven months later, both the Academy and TrizecHahn agreed on a twenty-year lease that allowed for the ceremony to be staged at the new venue.


title: Dolby Theatre

text: The Academy Awards were first hosted at the new theater for its 74th edition in 2002, marking the first time it was held in Hollywood since the 32nd ceremony at the Pantages Theatre in 1960. It has been the venue for all Academy Awards ceremonies held since, with the only exception being the 93rd Academy Awards in 2021—which were downsized and moved to Union Station due to the COVID-19 pandemic.


title: Dolby Theatre

text: The theater was sponsored, until February 2012, by the Eastman Kodak Company, which paid $75 million for naming rights to the building. In early 2012, Eastman Kodak filed for bankruptcy protection, thus ending its naming-rights deal. Then the theater's name was temporarily changed to the Hollywood and Highland Center at the suggestion of the venue's landlord.


title: Dolby Theatre

text: On May 1, 2012, it was announced that the venue would be renamed the Dolby Theatre, after Dolby Laboratories signed a 20-year naming rights deal. Dolby updated the sound system first by installing Dolby Atmos. The company plans to continue updating the auditorium with newer technologies as they become available.


title: Dolby Theatre

text: Besides the Academy Awards, the theatre has hosted other award presentations. The American Film Institute has held its Life Achievement Award gala at the theatre, It hosted the 3rd Annual Latin Grammy Awards in 2002.


title: Dolby Theatre

text: From September 2011 until early 2013, the venue hosted "Iris", a Cirque du Soleil residency show inspired by the history of cinema. Significant changes were made to the theater to accommodate the show, including adding lifts deep under the original floor. It was announced on November 29, 2012, that "Iris" would close on January 19, 2013, after only two seasons, due to lack of profit.


title: Dolby Theatre

text: The reality music competition series "American Idol" hosted its season finales from the Dolby Theatre during its original run on Fox in 2002, from 2004 to 2007, and in 2015 and 2016. From 2016 through 2021 (excluding 2020), the theatre hosted the live shows of the NBC reality competition "America's Got Talent".


title: Corn flakes

text: Corn flakes, or cornflakes, are a breakfast cereal made from toasting flakes of corn (maize). The cereal, originally made with wheat, was created by Will Kellogg in 1894 for patients at the Battle Creek Sanitarium where he worked with his brother John Kellogg who was the superintendent. The breakfast cereal proved popular among the patients and Kellogg subsequently started what became the Kellogg Company to produce corn flakes for the wider public. A patent for the process was granted in 1896, after a legal battle between the two brothers.


title: Corn flakes

text: With corn flakes becoming popular in the wider community, a previous patient at the sanitarium, C. W. Post, started to make rival products. Kellogg continued to experiment with various ingredients and different grains. In 1928, he started to manufacture Rice Krispies, another successful breakfast cereal.


title: Corn flakes

text: There are many generic brands of corn flakes produced by various manufacturers. As well as being used as a breakfast cereal, the crushed flakes can be a substitute for bread crumbs in recipes and can be incorporated into many cooked dishes.


title: Corn flakes

text: Corn flakes are a packaged cereal product formed from small toasted flakes of corn, usually served cold with milk and sometimes sugar. Since their original production, the plain flakes have been flavored with salt, sugar, and malt, and many successive products with additional ingredients have been manufactured such as sugar frosted flakes and honey & nut corn flakes.


title: Corn flakes

text: The development of the flaked cereal in 1894 has been variously described by John Kellogg, his wife Ella Eaton Kellogg, his younger brother Will, and other family members. There is considerable disagreement over who was involved in the discovery, and the role that they played. According to some accounts, Ella suggested rolling out the dough into thin sheets, and John developed a set of rollers for the purpose. According to others, John had the idea in a dream, and used equipment in his wife's kitchen to do the rolling. It is generally agreed that upon being called out one night, John Kellogg left a batch of wheat-berry dough behind. Rather than throwing it out the next morning, he sent it through the rollers and was surprised to obtain delicate flakes, which could then be baked. Will Kellogg was tasked with figuring out what had happened and recreating the process reliably. Ella and Will were often at odds, and their versions of the story tend to minimize or deny each other's involvement, while emphasizing their own. Tempering, the process the Kelloggs had discovered, was to become a fundamental technique of the flaked cereal industry.


title: Corn flakes

text: A patent for "Flaked Cereals and Process of Preparing Same" was filed on May 31, 1895, and issued on April 14, 1896 to John Harvey Kellogg as Patent No. 558,393. Significantly, the patent applied to a variety of types of grains, not just to wheat. John Harvey Kellogg was the only person named on the patent. Will later insisted that he, not Ella, had worked with John, and repeatedly asserted that he should have received more credit than he was given for the discovery of the flaked cereal.


title: Corn flakes

text: The flakes of grain, which the Kellogg brothers called "Granose", were a very popular food among the patients. The brothers then experimented with other flakes from other grains. In 1906, Will Keith Kellogg, who served as the business manager of the sanitarium, decided to try to mass-market the new food. At his new company, Battle Creek Toasted Corn Flake Company, he added sugar to the flakes to make them more palatable to a mass audience, but this caused a rift between his brother and him. In 1907, his company ran an ad campaign which offered a free box of cereal to any woman who winked at her grocer. To increase sales, in 1909 he added a special offer, the "Funny Jungleland Moving Pictures Booklet", which was made available to anyone who bought two boxes of the cereal. This same premium was offered for 22 years. At the same time, Kellogg also began experimenting with new grain cereals to expand its product line. Rice Krispies, his next great hit, first went on sale in 1928.


title: Corn flakes

text: There have been many mascots of Kellogg's Cornflakes. The most popular one is a green rooster named Cornelius "Corny" Rooster, which has been the mascot since his debut. In early commercials, he would speak the catchphrase "Wake up, up, up to Kellogg's Cornflakes!" Dallas McKennon and Andy Devine voiced him. Later, he stopped talking and simply crowed. The concept of using a stylized rooster originated from a suggestion by family friend Nansi Richards, a harpist from Wales, based on the similarity between "ceiliog", the Welsh word for "rooster", and Kellogg's (unrelated) surname.


title: Corn flakes

text: There are a wide variety of different recipes for dishes involving corn flakes and crushed corn flakes can even be a substitute for bread crumbs.


title: Corn flakes

text: "Honey joys" are a popular party snack in Australia. They are made by mixing corn flakes with honey, butter and sugar and baking in patty cases or muffin cups. A variant popular in the UK is "chocolate corn flake cakes", or "chocolate nests", made with corn flakes, dark chocolate, golden syrup and butter. Typically made at Easter for or by children, and topped with Mini Eggs In New Zealand, corn flakes are a core ingredient in Afghan biscuits, a chocolate biscuit made with corn flakes and topped with chocolate icing.


title: Andreas Pereira

text: Andreas Hugo Hoelgebaum Pereira (born 1 January 1996) is a professional footballer who plays as a midfielder for Premier League club Fulham.


title: Andreas Pereira

text: Born in Duffel, Belgium, he began his youth career with nearby club Lommel. At the age of nine, he joined Dutch club PSV Eindhoven, before signing for Manchester United in November 2011. Pereira made his first Premier League appearance in March 2015. While at United, he spent time on loan at Spanish clubs Granada and Valencia, Italian club Lazio and Brazilian club Flamengo.


title: Andreas Pereira

text: He played youth international football for both the country of his birth, Belgium, and his father's homeland, Brazil, before making his senior international debut for Brazil in September 2018.


title: Andreas Pereira

text: The son of former Brazilian professional footballer Marcos Pereira, Andreas Pereira was born in Duffel, Belgium, while his father was a player there. He joined PSV Eindhoven in 2005, when he was nine years old. In 2011, after impressing at the Manchester United Premier Cup, he became a target for several big English clubs, including Arsenal, Chelsea and Liverpool, but a visit from Manchester United manager Alex Ferguson in November 2011 convinced Pereira to sign for the Old Trafford club.


title: Andreas Pereira

text: Due to regulations regarding international transfers, the move could not be completed until Pereira's 16th birthday on 1 January 2012, and further complications with international clearance meant that his Manchester United debut was delayed until April 2012. He made his debut for the under-18s in a league match away to Sheffield Wednesday on 25 April 2012, but heavy rain meant the match had to be abandoned as a goalless draw after 35 minutes. He made two more appearances that season as the under-18s finished eighth out of 10 teams in their Premier Academy League group.


title: Andreas Pereira

text: After signing as an academy scholar in July 2012, Pereira became a regular in the under-18s in the 2012–13 season, making 20 appearances and scoring five goals. He also got his first taste of reserve team football during the season, coming on as a substitute for James Weir in a 3–1 win over Oldham Athletic in the Manchester Senior Cup, followed by another substitute appearance against Liverpool in the semi-finals of the Professional Development League. In recognition of his performances, on 7 January 2013, shortly after his 17th birthday, Pereira received his first professional contract. Ahead of the 2013–14 season, Pereira was named as Manchester United's captain for their 2013 Milk Cup campaign, and was named Player of the Tournament for his three goals as Manchester United won the Premier Section. He went on to feature heavily for both the under-18s and the under-21s, and was ever present in the inaugural UEFA Youth League; he also scored twice in three appearances in the FA Youth Cup, including a curling, 25-yard effort against Burnley in the third round. For the under-21s, he appeared in 17 out of 21 league matches as Manchester United finished third; he then scored the only goal in the semi-final against Liverpool, only for the team to lose to Chelsea in the final.


title: Andreas Pereira

text: Pereira began the 2014–15 season with silverware as Manchester United beat Manchester City 4–1 in the final of the Manchester Senior Cup on 7 August 2014. He made his senior debut three weeks later, coming on as a half-time substitute for Saidy Janko in a 4–0 away defeat to Milton Keynes Dons in the second round of the League Cup. On 15 March 2015, Pereira made his Premier League debut against Tottenham Hotspur, coming on as a 77th-minute substitute for Juan Mata in a 3–0 win for United.


title: Andreas Pereira

text: On 1 May, he signed a new contract with Manchester United until at least June 2018. Eighteen days later, Pereira was voted Manchester United's under-21 player of the year for 2014–15.


title: Andreas Pereira

text: On 21 July, Pereira scored his first goal for Manchester United's senior squad in the 3–1 win against the San Jose Earthquakes in the 2015 International Champions Cup, after coming on as a second-half substitute. He made his first competitive start for the senior team on 23 September 2015, in the third round of the League Cup, and scored a free kick in the eventual 3–0 win over Ipswich Town.


title: Andreas Pereira

text: On 26 August 2016, Pereira joined Spanish club Granada on a season-long loan deal. He made his debut in La Liga two days later, replacing Luís Martins in the 55th minute of a 5–1 loss at UD Las Palmas.


title: Andreas Pereira

text: Pereira scored his first goal for the "Nazaríes" on 3 December, opening a 2–1 home win over fellow Andalusians Sevilla FC. On 6 February 2017, he netted the only goal of a win over Las Palmas at the Estadio Nuevo Los Cármenes, with a long-range strike. Eleven days later, he was again on the scoresheet for a 4–1 victory against Real Betis at the same ground, but was sent off for a push; he was banned for two games and the club fined €180.


title: Andreas Pereira

text: On 1 September 2017, Valencia announced the arrival of Pereira to the club on a season-long loan deal. He made his debut in a 0–0 home draw against Atlético Madrid eight days later, and scored his only goal for "Los Che" on 15 October, with a long-range strike as a substitute to conclude a 6–3 win at Real Betis.


title: Andreas Pereira

text: On 2 March 2019, Pereira scored his first Premier League goal in a home match against Southampton. The goal later earned him Manchester United's goal of the season for 2018-19 season. He also recorded an assist for Romelu Lukaku in the same match. On 7 March 2019, Pereira was featured in the starting lineup during the historic Champions League Round of 16 (2nd Leg) win vs PSG, where the team was able to come back from a 2-goal deficit they conceded at home and win on away goals at the Parc des Princes, a record that has never been broken before.


title: Andreas Pereira

text: On 5 July 2019, it was announced that Pereira had signed a new four-year contract with the option to extend by a further year. On 11 August 2019, he started in Manchester United's opening day 4–0 win against Chelsea, in which he assisted Anthony Martial for the second goal. He scored his first goal of the season two months later, on 10 November 2019, in a 3–1 home win against Brighton.


title: Andreas Pereira

text: On 2 October 2020, Lazio announced the arrival of Pereira to the club on a season-long loan. On 1 November 2020, He scored his first Serie A goal in a 4-3 away win against Torino.


title: Andreas Pereira

text: On 20 August 2021, Pereira joined Flamengo on a one-year loan. The Brazilian club agreed to pay €1m for the loan. In the final of Copa Libertadores 2021, he made a decisive mistake that caused Flamengo to lose against Palmeiras.


title: Andreas Pereira

text: On 11 July 2022, Fulham announced the signing of Pereira on a four-year contract, for an undisclosed fee, understood to be worth £10m with add-ons. He made his debut for Fulham on 6 August, starting and playing 89 minutes in a 2–2 home draw against Liverpool.


title: Andreas Pereira

text: Born in Belgium to a Brazilian father and a mother of German descent, Pereira is eligible to represent either Belgium or Brazil at international level. He initially represented Belgium at under-15, under-16 and under-17 levels, but has since stated, "My heart is Brazilian." He received his first Brazil call-up in 2014, joining the under-20 team on their successful Panda Cup campaign in China. At the 2015 FIFA U-20 World Cup in New Zealand, Pereira equalised in the final against Serbia, but Brazil lost 2–1 after extra time. In total, he scored twice in seven appearances at under-20 level. Pereira made one appearance and scored one goal for Brazil at under-23 level, in a friendly against South Africa in March 2016.


title: Andreas Pereira

text: On 17 August 2018, he received his first senior call up for the friendly matches against the United States and El Salvador. He made his debut against El Salvador on 11 September, as the first player in over 100 years to play for Brazil having been born outside of the country.


title: OpenGL

text: OpenGL (Open Graphics Library) is a cross-language, cross-platform application programming interface (API) for rendering 2D and 3D vector graphics. The API is typically used to interact with a graphics processing unit (GPU), to achieve hardware-accelerated rendering.


title: OpenGL

text: Silicon Graphics, Inc. (SGI) began developing OpenGL in 1991 and released it on June 30, 1992; applications use it extensively in the fields of computer-aided design (CAD), virtual reality, scientific visualization, information visualization, flight simulation, and video games. Since 2006, OpenGL has been managed by the non-profit technology consortium Khronos Group.


title: OpenGL

text: The OpenGL specification describes an abstract API for drawing 2D and 3D graphics. Although it is possible for the API to be implemented entirely in software, it is designed to be implemented mostly or entirely in hardware.


title: OpenGL

text: The API is defined as a set of functions which may be called by the client program, alongside a set of named integer constants (for example, the constant GL_TEXTURE_2D, which corresponds to the decimal number 3553). Although the function definitions are superficially similar to those of the programming language C, they are language-independent. As such, OpenGL has many language bindings, some of the most noteworthy being the JavaScript binding WebGL (API, based on OpenGL ES 2.0, for 3D rendering from within a web browser); the C bindings WGL, GLX and CGL; the C binding provided by iOS; and the Java and C bindings provided by Android.


title: OpenGL

text: In addition to being language-independent, OpenGL is also cross-platform. The specification says nothing on the subject of obtaining and managing an OpenGL context, leaving this as a detail of the underlying windowing system. For the same reason, OpenGL is purely concerned with rendering, providing no APIs related to input, audio, or windowing.


title: OpenGL

text: OpenGL is no longer in active development: whereas between 2001 and 2014 OpenGL specification was updated mostly on a yearly basis, with two releases (3.1 and 3.2) taking place in 2009 and three (3.3, 4.0 and 4.1) in 2010, the latest OpenGL specification 4.6 was released in 2017 after a three-year break and was limited to inclusion of eleven existing ARB and EXT extensions into the core profile.


title: OpenGL

text: Active development of OpenGL was dropped in favor of Vulkan API released in 2016 and codenamed glNext during initial development. In 2017, Khronos Group announced that OpenGL ES will not have new versions and has since concentrated on development of Vulkan and other technologies. As a result, certain capabilities offered by modern GPUs, e.g. ray tracing, are not supported by OpenGL.


title: OpenGL

text: New versions of the OpenGL specifications are released by the Khronos Group, each of which extends the API to support various new features. The details of each version are decided by consensus between the Group's members, including graphics card manufacturers, operating system designers, and general technology companies such as Mozilla and Google.


title: OpenGL

text: In addition to the features required by the core API, graphics processing unit (GPU) vendors may provide additional functionality in the form of "extensions". Extensions may introduce new functions and new constants, and may relax or remove restrictions on existing OpenGL functions. Vendors can use extensions to expose custom APIs without needing support from other vendors or the Khronos Group as a whole, which greatly increases the flexibility of OpenGL. All extensions are collected in, and defined by, the OpenGL Registry.


title: OpenGL

text: Each extension is associated with a short identifier, based on the name of the company which developed it. For example, Nvidia's identifier is NV, which is part of the extension name codice_1, the constant codice_2, and the function codice_3. If multiple vendors agree to implement the same functionality using the same API, a shared extension may be released, using the identifier EXT. In such cases, it could also happen that the Khronos Group's Architecture Review Board gives the extension their explicit approval, in which case the identifier ARB is used.


title: OpenGL

text: The features introduced by each new version of OpenGL are typically formed from the combined features of several widely implemented extensions, especially extensions of type ARB or EXT.


title: OpenGL

text: The OpenGL Architecture Review Board released a series of manuals along with the specification which have been updated to track changes in the API. These are commonly referred to by the colors of their covers:


title: OpenGL

text: The earliest versions of OpenGL were released with a companion library called the OpenGL Utility Library (GLU). It provided simple, useful features which were unlikely to be supported in contemporary hardware, such as tessellating, and generating mipmaps and primitive shapes. The GLU specification was last updated in 1998 and depends on OpenGL features which are now deprecated.


title: OpenGL

text: Given that creating an OpenGL context is quite a complex process, and given that it varies between operating systems, automatic OpenGL context creation has become a common feature of several game-development and user-interface libraries, including SDL, Allegro, SFML, FLTK, and Qt. A few libraries have been designed solely to produce an OpenGL-capable window. The first such library was OpenGL Utility Toolkit (GLUT), later superseded by freeglut. GLFW is a newer alternative.


title: OpenGL

text: Given the high workload involved in identifying and loading OpenGL extensions, a few libraries have been designed which load all available extensions and functions automatically. Examples include OpenGL Easy Extension library (GLEE), OpenGL Extension Wrangler Library (GLEW) and glbinding. Extensions are also loaded automatically by most language bindings, such as JOGL and PyOpenGL.


title: OpenGL

text: Mesa 3D is an open-source implementation of OpenGL. It can do pure software rendering, and it may also use hardware acceleration on BSD, Linux, and other platforms by taking advantage of the Direct Rendering Infrastructure. As of version 20.0, it implements version 4.6 of the OpenGL standard.


title: OpenGL

text: In the 1980s, developing software that could function with a wide range of graphics hardware was a real challenge. Software developers wrote custom interfaces and drivers for each piece of hardware. This was expensive and resulted in multiplication of effort.


title: OpenGL

text: By the early 1990s, Silicon Graphics (SGI) was a leader in 3D graphics for workstations. Their IRIS GL API became the industry standard, used more widely than the open standards-based PHIGS. This was because IRIS GL was considered easier to use, and because it supported immediate mode rendering. By contrast, PHIGS was considered difficult to use and outdated in functionality.


title: OpenGL

text: SGI's competitors (including Sun Microsystems, Hewlett-Packard and IBM) were also able to bring to market 3D hardware supported by extensions made to the PHIGS standard, which pressured SGI to open source a version of IRIS GL as a public standard called OpenGL.


title: OpenGL

text: However, SGI had many customers for whom the change from IRIS GL to OpenGL would demand significant investment. Moreover, IRIS GL had API functions that were irrelevant to 3D graphics. For example, it included a windowing, keyboard and mouse API, in part because it was developed before the X Window System and Sun's NeWS. And, IRIS GL libraries were unsuitable for opening due to licensing and patent issues. These factors required SGI to continue to support the advanced and proprietary Iris Inventor and Iris Performer programming APIs while market support for OpenGL matured.


title: OpenGL

text: One of the restrictions of IRIS GL was that it only provided access to features supported by the underlying hardware. If the graphics hardware did not support a feature natively, then the application could not use it. OpenGL overcame this problem by providing software implementations of features unsupported by hardware, allowing applications to use advanced graphics on relatively low-powered systems. OpenGL standardized access to hardware, pushed the development responsibility of hardware interface programs (device drivers) to hardware manufacturers, and delegated windowing functions to the underlying operating system. With so many different kinds of graphics hardware, getting them all to speak the same language in this way had a remarkable impact by giving software developers a higher-level platform for 3D-software development.


title: OpenGL

text: In 1992, SGI led the creation of the OpenGL Architecture Review Board (OpenGL ARB), the group of companies that would maintain and expand the OpenGL specification in the future.


title: OpenGL

text: In 1994, SGI played with the idea of releasing something called "OpenGL++" which included elements such as a scene-graph API (presumably based on their Performer technology). The specification was circulated among a few interested parties – but never turned into a product.


title: OpenGL

text: In 1996, Microsoft released Direct3D, which eventually became the main competitor of OpenGL. Over 50 game developers signed an open letter to Microsoft, released on June 12, 1997, calling on the company to actively support OpenGL. On December 17, 1997, Microsoft and SGI initiated the Fahrenheit project, which was a joint effort with the goal of unifying the OpenGL and Direct3D interfaces (and adding a scene-graph API too). In 1998, Hewlett-Packard joined the project. It initially showed some promise of bringing order to the world of interactive 3D computer graphics APIs, but on account of financial constraints at SGI, strategic reasons at Microsoft, and a general lack of industry support, it was abandoned in 1999.


title: OpenGL

text: In July 2006, the OpenGL Architecture Review Board voted to transfer control of the OpenGL API standard to the Khronos Group.


title: OpenGL

text: The first version of OpenGL, version 1.0, was released on June 30, 1992, by Mark Segal and Kurt Akeley. Since then, OpenGL has occasionally been extended by releasing a new version of the specification. Such releases define a baseline set of features which all conforming graphics cards must support, and against which new extensions can more easily be written. Each new version of OpenGL tends to incorporate several extensions which have widespread support among graphics-card vendors, although the details of those extensions may be changed.