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Thorne–Hawking–Preskill Bet
The Thorne–Hawking–Preskill bet was a public bet on the outcome of the black hole information paradox made in 1997 by physics theorists Kip Thorne and Stephen Hawking on the one side, and John Preskill on the other, according to the document they signed 6 February 1997, as shown in Hawking's ''The Universe in a Nutshell''. Overview Thorne & Hawking argued that since general relativity made it impossible for black holes to radiate, and lose information, the mass-energy and information carried by Hawking radiation must be "new", and must not originate from inside the black hole event horizon. Since this contradicted the idea under quantum mechanics of microcausality, quantum mechanics would need to be rewritten. Preskill argued the opposite, that since quantum mechanics suggests that the information emitted by a black hole relates to information that fell in at an earlier time, the view of black holes given by general relativity must be modified in some way. The winning side ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hole Information Paradox
The black hole information paradox is a puzzle that appears when the predictions of quantum mechanics and general relativity are combined. The theory of general relativity predicts the existence of black holes that are regions of spacetime from which nothing — not even light — can escape. In the 1970s, Stephen Hawking applied the rules of quantum mechanics to such systems and found that an isolated black hole would emit a form of radiation called Hawking radiation. Hawking also argued that the detailed form of the radiation would be independent of the initial state of the black hole and would depend only on its mass, electric charge and angular momentum. The information paradox appears when one considers a process in which a black hole is formed through a physical process and then evaporates away entirely through Hawking radiation. Hawking's calculation suggests that the final state of radiation would retain information only about the total mass, electric charge and angular m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric (general Relativity)
In general relativity, the metric tensor (in this context often abbreviated to simply the metric) is the fundamental object of study. It may loosely be thought of as a generalization of the gravitational potential of Newtonian gravitation. The metric captures all the geometric and causal structure of spacetime, being used to define notions such as time, distance, volume, curvature, angle, and separation of the future and the past. Notation and conventions Throughout this article we work with a metric signature that is mostly positive (); see sign convention. The gravitation constant G will be kept explicit. This article employs the Einstein summation convention, where repeated indices are automatically summed over. Definition Mathematically, spacetime is represented by a four-dimensional differentiable manifold M and the metric tensor is given as a covariant, second- degree, symmetric tensor on M, conventionally denoted by g. Moreover, the metric is required to be nondeg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Holes
A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. Although it has a great effect on the fate and circumstances of an object crossing it, it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly. Objects whose gravitational fields are too strong for light to escape were first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Wager
A scientific wager is a wager whose outcome is settled by scientific method. They typically consist of an offer to pay a certain sum of money on the scientific proof or disproof of some currently-uncertain statement. Some wagers have specific date restrictions for collection, but many are open. Wagers occasionally exert a powerful galvanizing effect on society and the scientific community. Notable scientists who have made scientific wagers include Stephen Hawking and Richard Feynman. Stanford Linear Accelerator has an open book containing about 35 bets in particle physics dating back to 1980; many are still unresolved. Notable scientific wagers * In 1870, Alfred Russel Wallace bet a flat-Earth theorist named John Hampden that he could prove the flat Earth hypothesis incorrect. The sum staked was £500 (equivalent to about £ in present-day terms). A test (now known as the Bedford Level experiment) involving a stretch of the Old Bedford River, in Norfolk, was agreed on: Wallace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nova (American TV Series)
''Nova'' (stylized as ''NOVΛ'') is an American popular science television program produced by WGBH in Boston, Massachusetts, since 1974. It is broadcast on PBS in the United States, and in more than 100 other countries. The program has won many major television awards. ''Nova'' often includes interviews with scientists doing research in the subject areas covered and occasionally includes footage of a particular discovery. Some episodes have focused on the history of science. Examples of topics covered include the following: Colditz Castle, the Drake equation, elementary particles, the 1980 eruption of Mount St. Helens, Fermat's Last Theorem, the AIDS epidemic, global warming, moissanite, Project Jennifer, storm chasing, Unterseeboot 869, Vinland, Tarim mummies, and the COVID-19 pandemic. The ''Nova'' programs have been praised for their pacing, writing, and editing. Websites that accompany the segments have also won awards. Episodes History ''Nova'' was first aired o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bantam Books
Bantam Books is an American publishing house owned entirely by parent company Random House, a subsidiary of Penguin Random House; it is an imprint of the Random House Publishing Group. It was formed in 1945 by Walter B. Pitkin, Jr., Sidney B. Kramer, and Ian and Betty Ballantine, with funding from Grosset & Dunlap and Curtis Publishing Company. It has since been purchased several times by companies including National General, Carl Lindner's American Financial and, most recently, Bertelsmann; it became part of Random House in 1998, when Bertelsmann purchased it to form Bantam Doubleday Dell. It began as a mass market publisher, mostly of reprints of hardcover books, with some original paperbacks as well. It expanded into both trade paperback and hardcover books, including original works, often reprinted in house as mass-market editions. History The company was failing when Oscar Dystel, who had previously worked at Esquire and as editor on Coronet magazine was hired in 1954 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus and was the first such source widely accepted to be a black hole. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources detectable from Earth, producing a peak X-ray flux density of (). It remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 21.2 times the mass of the Sun and has been shown to be too small to be any known kind of normal star or other likely object besides a black hole. If so, the radius of its event horizon has "as upper bound to the linear dimension of the source region" of occasional X-ray bursts lasting only for about 1 ms. Cygnus X-1 belongs to a high-mass X-ray binary system, located about 2.22 kiloparsecs from the Sun, that includes a blue supergiant variable star designated HDE 226868, which it orbits at about 0.2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penthouse (magazine)
''Penthouse'' is a men's magazine founded by Bob Guccione. It combines urban lifestyle articles and softcore pornographic pictures of women that, in the 1990s, evolved into hardcore pornographic pictures of women. Although Guccione was American, the magazine was founded in 1965 in the United Kingdom. Beginning in September 1969, it was sold in the United States as well. ''Penthouse'' has been owned by Penthouse Global Media Inc. since 2016. The assets of Penthouse Global Media were bought out by WGCZ Ltd. (the owners of XVideos) in June 2018 after winning a bankruptcy auction bid. The magazine's centerfold models are known as ''Penthouse'' Pets, and customarily wear a distinctive necklace in the form of a stylized key which incorporates both the Mars and Venus symbols in its design. Bob Guccione At the height of its success, Guccione, who died in 2010, was considered one of the richest men in the United States. In 1982 he was listed in the Forbes 400 ranking of wealthiest peopl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Private Eye
''Private Eye'' is a British fortnightly satire, satirical and current affairs (news format), current affairs news magazine, founded in 1961. It is published in London and has been edited by Ian Hislop since 1986. The publication is widely recognised for its prominent criticism and Parody, lampooning of public figures. It is also known for its in-depth investigative journalism into under-reported scandals and cover-ups. ''Private Eye'' is Britain's best-selling current affairs magazine, and such is its long-term popularity and impact that many of recurring in-jokes in Private Eye, its recurring in-jokes have entered popular culture in the United Kingdom. The magazine bucks the trend of declining circulation for print media, having recorded its highest ever circulation in the second half of 2016. It is privately owned and highly profitable. With a "deeply conservative resistance to change", it has resisted moves to online content or glossy format: it has always been printed o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymptote
In analytic geometry, an asymptote () of a curve is a line such that the distance between the curve and the line approaches zero as one or both of the ''x'' or ''y'' coordinates tends to infinity. In projective geometry and related contexts, an asymptote of a curve is a line which is tangent to the curve at a point at infinity. The word asymptote is derived from the Greek ἀσύμπτωτος (''asumptōtos'') which means "not falling together", from ἀ priv. + σύν "together" + πτωτ-ός "fallen". The term was introduced by Apollonius of Perga in his work on conic sections, but in contrast to its modern meaning, he used it to mean any line that does not intersect the given curve. There are three kinds of asymptotes: ''horizontal'', ''vertical'' and ''oblique''. For curves given by the graph of a function , horizontal asymptotes are horizontal lines that the graph of the function approaches as ''x'' tends to Vertical asymptotes are vertical lines near which the fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lorentz Transformation
In physics, the Lorentz transformations are a six-parameter family of linear transformations from a coordinate frame in spacetime to another frame that moves at a constant velocity relative to the former. The respective inverse transformation is then parameterized by the negative of this velocity. The transformations are named after the Dutch physicist Hendrik Lorentz. The most common form of the transformation, parametrized by the real constant v, representing a velocity confined to the -direction, is expressed as \begin t' &= \gamma \left( t - \frac \right) \\ x' &= \gamma \left( x - v t \right)\\ y' &= y \\ z' &= z \end where and are the coordinates of an event in two frames with the origins coinciding at 0, where the primed frame is seen from the unprimed frame as moving with speed along the -axis, where is the speed of light, and \gamma = \left ( \sqrt\right )^ is the Lorentz factor. When speed is much smaller than , the Lorentz factor is negligibly different from 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
