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π MARS-500
The Mars-500 mission was a psychosocial isolation experiment conducted between 2007 and 2011 by Russia, the European Space Agency and China, in preparation for an unspecified future crewed spaceflight to the planet Mars. The experiment's facility was located at the Russian Academy of Sciences' Institute of Biomedical Problems (IBMP) in Moscow, Russia.
Between 2007 and 2011, three different crews of volunteers lived and worked in a mock-up spacecraft at IBMP. The final stage of the experiment, which was intended to simulate a 520-day crewed mission, was conducted by an all-male crew consisting of three Russians (Alexey Sitev, Sukhrob Kamolov, Alexander Smoleevskij), a Frenchman (Romain Charles), an Italian (Diego Urbina) and a Chinese citizen (Yue Wang). The mock-up facility simulated an Earth-Mars shuttle spacecraft, an ascent-descent craft, and the Martian surface. The volunteers who participated in the three stages included professionals with experience in engineering, medicine, biology, and human spaceflight. The experiment yielded important data on the physiological, social and psychological effects of long-term close-quarters isolation.
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- "MARS-500" | 2015-08-29 | 49 Upvotes 14 Comments
π Kyshtym Disaster
The Kyshtym disaster, sometimes referred to as the Mayak disaster or Ozyorsk disaster in newer sources, was a radioactive contamination accident that occurred on 29 September 1957 at Mayak, a plutonium production site for nuclear weapons and nuclear fuel reprocessing plant located in the closed city of Chelyabinsk-40 (now Ozyorsk) in Chelyabinsk Oblast, Russian SFSR, Soviet Union.
The disaster was the second worst nuclear incident (by radioactivity released) after the Chernobyl disaster. It measured as a Level 6 disaster on the International Nuclear Event Scale (INES), making it the third highest on the INES (which ranks by population impact), behind Chernobyl (evacuated 335,000 people) and the Fukushima Daiichi nuclear disaster (evacuated 154,000 people) which are both Level 7 on the INES. At least twenty-two villages were exposed to radiation from the Kyshtym disaster, with a total population of around 10,000 people evacuated. Some were evacuated after a week, but it took almost two years for evacuations to occur at other sites.
The disaster spread hot particles over more than 52,000 square kilometres (20,000Β sqΒ mi), where at least 270,000 people lived. Since Chelyabinsk-40 (later renamed Chelyabinsk-65 until 1994) was not marked on maps, the disaster was named after Kyshtym, the nearest known town.
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- "Kyshtym Disaster" | 2021-10-13 | 60 Upvotes 37 Comments
π GΓΆmbΓΆc
The gΓΆmbΓΆc (Hungarian:Β [ΛΙ‘ΓΈmbΓΈtΝ‘s]) is a convex three-dimensional homogeneous body that when resting on a flat surface has just one stable and one unstable point of equilibrium. Its existence was conjectured by the Russian mathematician Vladimir Arnold in 1995 and proven in 2006 by the Hungarian scientists GΓ‘bor Domokos and PΓ©ter VΓ‘rkonyi. The gΓΆmbΓΆc shape is not unique; it has countless varieties, most of which are very close to a sphere and all with a very strict shape tolerance (about 0.1Β mm per 100Β mm).
The most famous solution, capitalized as GΓΆmbΓΆc to distinguish it from the generic gΓΆmbΓΆc, has a sharpened top, as shown in the photo. Its shape helped to explain the body structure of some tortoises in relation to their ability to return to equilibrium position after being placed upside down. Copies of the gΓΆmbΓΆc have been donated to institutions and museums, and the largest one was presented at the World Expo 2010 in Shanghai in China. In December 2017, a 4.5Β m gΓΆmbΓΆc statue was installed in the Corvin Quarter in Budapest.
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- "GΓΆmbΓΆc" | 2019-01-20 | 113 Upvotes 19 Comments
π Monty Hall Problem
The Monty Hall problem is a brain teaser, in the form of a probability puzzle, loosely based on the American television game show Let's Make a Deal and named after its original host, Monty Hall. The problem was originally posed (and solved) in a letter by Steve Selvin to the American Statistician in 1975 (Selvin 1975a), (Selvin 1975b). It became famous as a question from a reader's letter quoted in Marilyn vos Savant's "Ask Marilyn" column in Parade magazine in 1990 (vos Savant 1990a):
Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?
Vos Savant's response was that the contestant should switch to the other door (vos Savant 1990a). Under the standard assumptions, contestants who switch have a 2/3 chance of winning the car, while contestants who stick to their initial choice have only a 1/3 chance.
The given probabilities depend on specific assumptions about how the host and contestant choose their doors. A key insight is that, under these standard conditions, there is more information about doors 2 and 3 than was available at the beginning of the game when door 1 was chosen by the player: the host's deliberate action adds value to the door he did not choose to eliminate, but not to the one chosen by the contestant originally. Another insight is that switching doors is a different action than choosing between the two remaining doors at random, as the first action uses the previous information and the latter does not. Other possible behaviors than the one described can reveal different additional information, or none at all, and yield different probabilities. Yet another insight is that your chance of winning by switching doors is directly related to your chance of choosing the winning door in the first place: if you choose the correct door on your first try, then switching loses; if you choose a wrong door on your first try, then switching wins; your chance of choosing the correct door on your first try is 1/3, and the chance of choosing a wrong door is 2/3.
Many readers of vos Savant's column refused to believe switching is beneficial despite her explanation. After the problem appeared in Parade, approximately 10,000 readers, including nearly 1,000 with PhDs, wrote to the magazine, most of them claiming vos Savant was wrong (Tierney 1991). Even when given explanations, simulations, and formal mathematical proofs, many people still do not accept that switching is the best strategy (vos Savant 1991a). Paul ErdΕs, one of the most prolific mathematicians in history, remained unconvinced until he was shown a computer simulation demonstrating vos Savantβs predicted result (Vazsonyi 1999).
The problem is a paradox of the veridical type, because the correct choice (that one should switch doors) is so counterintuitive it can seem absurd, but is nevertheless demonstrably true. The Monty Hall problem is mathematically closely related to the earlier Three Prisoners problem and to the much older Bertrand's box paradox.
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- "Monty Hall Problem" | 2022-06-09 | 24 Upvotes 116 Comments
- "Monty Hall Problem" | 2019-10-24 | 122 Upvotes 252 Comments
- "Monty Hall problem" | 2010-02-22 | 14 Upvotes 27 Comments
π Inco Superstack
The Inco Superstack in Sudbury, Ontario, with a height of 381 metres (1,250Β ft), is the tallest chimney in Canada and the Western hemisphere, and the second tallest freestanding chimney in the world after the GRES-2 Power Station in Kazakhstan. It is also the second tallest freestanding structure of any type in Canada, behind the CN Tower but ahead of First Canadian Place. It is the 51st tallest freestanding structure in the world. The Superstack is located on top of the largest nickel smelting operation in the world at Vale's Copper Cliff processing facility in the city of Greater Sudbury.
In 2018, Vale announced that the stack would be decommissioned and dismantled beginning in 2020. Two new, smaller stacks were constructed under the company's Clean Atmospheric Emissions Reduction Project. In July 2020, Vale announced that the Superstack had been officially taken out of service, but would remain operational in standby mode for two more months as a backup in the event of a malfunction in the new system, following which the dismantling of the Superstack would begin. As of August 2021, however, Vale has not yet announced the awarding of a demolition contract on the Superstack, and it remains unknown when demolition will actually begin.
In addition to further reducing sulphur dioxide emissions by 85 per cent, the decommissioning of the stack is expected to cut the complex's natural gas consumption in half.
Discussed on
- "Inco Superstack" | 2022-09-04 | 27 Upvotes 13 Comments
π Mary Kenneth Keller
Mary Kenneth Keller, B.V.M. (December 17, 1913 β January 10, 1985) was an American Roman Catholic religious sister, educator and pioneer in computer science. She and Irving C. Tang were the first two people to earn a doctorate in computer science in the United States.
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- "Mary Kenneth Keller" | 2020-12-27 | 32 Upvotes 6 Comments
π Hyper Text Coffee Pot Control Protocol
The Hyper Text Coffee Pot Control Protocol (HTCPCP) is a facetious communication protocol for controlling, monitoring, and diagnosing coffee pots. It is specified in RFC 2324, published on 1 April 1998 as an April Fools' Day RFC, as part of an April Fools prank. An extension, HTCPCP-TEA, was published as RFC 7168 on 1 April 2014 to support brewing teas, which is also an April Fools' Day RFC.
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- "Hyper Text Coffee Pot Control Protocol" | 2020-01-24 | 11 Upvotes 2 Comments
- "HTTP status code 418 (I'm a teapot)" | 2017-01-09 | 16 Upvotes 3 Comments
π Min Chiu Li
Min Chiu Li (Chinese: ζζζ±; pinyin: LΗ MΗnqiΓΊ; 1919β1980) was a Chinese-American oncologist and cancer researcher. Li was the first scientist to use chemotherapy to cure widely metastatic, malignant cancer.
Discussed on
- "Min Chiu Li" | 2019-08-26 | 130 Upvotes 8 Comments
π Russian Domesticated Red Fox
The Russian domesticated red fox is a form of the wild red fox (Vulpes vulpes) which has been domesticated to an extent, under laboratory conditions. They are the result of an experiment which was designed to demonstrate the power of selective breeding to transform species, as described by Charles Darwin in On the Origin of Species. The experiment was purposely designed to replicate the process that had produced dogs from wolves, by recording the changes in foxes, when in each generation only the most tame foxes were allowed to breed. In short order, the descendant foxes became tamer and more dog-like in their behavior.
The program was started in 1959 in the Soviet Union by zoologist Dmitry Belyayev and it has been in continuous operation since. Today, the experiment is under the supervision of Lyudmila Trut, in Russia, at the Institute of Cytology and Genetics in Novosibirsk.
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- "Russian Domesticated Red Fox" | 2015-11-06 | 96 Upvotes 30 Comments