History UsefulNotes / BlackHoles

22nd Nov '16 5:20:26 PM darkzonork
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Another useful note is that black holes are one of the predictions derived from Einstein's theory of general {{UsefulNotes/relativity}} - and even in its context certain theorists saw the predictions of black holes in relativity and [[http://arxiv.org/abs/gr-qc/0412058 expressed doubts]] at least about the classical model. One such theorist was, initially, Einstein himself, who rejected the premise of a black hole rather strongly. Black holes just didn't make sense, especially how they muck up the nice wonderful understanding of space and time we (think) have.

to:

Another useful note is that black holes are one of the predictions derived from Einstein's theory of general {{UsefulNotes/relativity}} - and even in its context certain theorists saw the predictions of black holes in relativity and [[http://arxiv.org/abs/gr-qc/0412058 expressed doubts]] at least about the classical model. One such theorist was, initially, Einstein himself, who rejected the premise of a black hole rather strongly. Black holes just didn't make sense, especially how they muck up the nice wonderful understanding of space and time we (think) (think we) have.
22nd Nov '16 5:19:19 PM darkzonork
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Another useful note is that black holes are one of the predictions derived from Einstein's theory of general {{UsefulNotes/relativity}} - and even in its context certain theorists saw the predictions of black holes in relativity and [[http://arxiv.org/abs/gr-qc/0412058 expressed doubts]] at least about the classical model. One such theorist was, initially, Einstein himself, who rejected the premise of a black hole rather strongly. Black holes just didn't make sense, especially how they muck up the nice wonderful understanding of space and time we (think we) have.

to:

Another useful note is that black holes are one of the predictions derived from Einstein's theory of general {{UsefulNotes/relativity}} - and even in its context certain theorists saw the predictions of black holes in relativity and [[http://arxiv.org/abs/gr-qc/0412058 expressed doubts]] at least about the classical model. One such theorist was, initially, Einstein himself, who rejected the premise of a black hole rather strongly. Black holes just didn't make sense, especially how they muck up the nice wonderful understanding of space and time we (think we) (think) have.
20th Oct '16 5:01:23 PM ScorpiusOB1
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* Magic: Black holes don't gain any super-magic powers of suction when they become black holes. Their mass exerts the same gravitational force as a star, planet, or any other object of the same mass. If our sun were suddenly turned into a black hole, nothing would happen to us. [[note]] other than the fact that all that energy normally radiated from the sun is suddenly gone[[/note]] Well, nothing would happen to the planet, though we'd most likely die off from cold and starvation. If we wanted to study a black hole, we could put a probe in orbit around it the same way we put probes around other astronomical bodies. It's not going to instantly spiral to its doom (at least not any faster than it would around anything else)[[note]]However, since a black hole is ''far'' smaller than a star and does not emit radiation except very faint Hawking radiation, the probe could orbit it much closer. Tidal forces aside, if it's too close to the hole then itcould destroy the probe, so if it orbits very close, it could be unable to leave its orbit unless it had a very powerful engine.[[/note]]

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* Magic: Black holes don't gain any super-magic powers of suction when they become black holes. Their mass exerts the same gravitational force as a star, planet, or any other object of the same mass. If our sun were suddenly turned into a black hole, nothing would happen to us. [[note]] other than the fact that all that energy normally radiated from the sun is suddenly gone[[/note]] Well, nothing would happen to the planet, though we'd most likely die off from cold and starvation. If we wanted to study a black hole, we could put a probe in orbit around it the same way we put probes around other astronomical bodies. It's not going to instantly spiral to its doom (at least not any faster than it would around anything else)[[note]]However, else)[[note]]However since a black hole (except very massive ones) is ''far'' smaller than a star and does not emit radiation except very faint feeble Hawking radiation, the probe could orbit it much closer. Tidal be orbiting one at relatively close distances. However tidal forces aside, if it's too close to aside that could destroy said probe unless the hole then itcould destroy was large enough to have weak ones, below a certain point the probe, so if it orbits very close, it could probe would be unable to leave its keep a stable orbit unless it had a very powerful engine.[[/note]]
and would need to use an engine in order not to fall into the black hole (once that engine's fuel is used up, said goodbye to it)[[/note]]
1st Oct '16 11:22:52 AM Morgenthaler
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To learn more cool facts about black holes, please read [[IrregularWebcomic David Morgan-Mar's]] [[TheRant rant]] [[http://www.irregularwebcomic.net/2175.html here]]. Or [[http://www.reddit.com/r/askscience/comments/f1lgu/what_would_happen_if_the_event_horizons_of_two/ this]] science question on Reddit. Seriously, they're awesome.

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To learn more cool facts about black holes, please read [[IrregularWebcomic [[Webcomic/IrregularWebcomic David Morgan-Mar's]] [[TheRant rant]] [[http://www.irregularwebcomic.net/2175.html here]]. Or [[http://www.reddit.com/r/askscience/comments/f1lgu/what_would_happen_if_the_event_horizons_of_two/ this]] science question on Reddit. Seriously, they're awesome.
14th Jul '16 11:05:28 AM MsChibi
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# You reverse yourself in time, but fail to move in space. You think you are outside the Black Hole, and so does your magical FTL ship, but you're not. Eventually you hit the singularity and disintegrate, but you don't even notice. You are dead.

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# You reverse yourself in time, but fail to move in space. [[LotusEaterMachine You think you are outside the Black Hole, and so does your magical FTL ship, but you're not.not]]. Eventually you hit the singularity and disintegrate, but you don't even notice. You are dead.
1st Jun '16 10:25:59 PM AnotherGuy
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Have fun arguing with infinity.

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In fact, it's been noted that black holes are nature's way of [[RealityBreakingParadox dividing by zero]]. Have fun arguing with infinity.
16th May '16 10:51:21 AM BurgerLord
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# The desired scenario - you appear outside the Black Hole with full memory of your experience and data in hand, you don't go in again, and the universe somehow doesn't switch off. Congratulations, not only have you rewound ''the entire universe except yourself,'' defying all laws of physics, but you have defied all possible logic too. You are now God. Or possibly [[Series/DoctorWho The Doctor]].

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# The desired scenario - you appear outside the Black Hole with full memory of your experience and data in hand, you don't go in again, and the universe somehow doesn't switch off. Congratulations, not only have you rewound ''the entire universe except yourself,'' defying all laws of physics, but [[RealityWarper you have defied all possible logic logic]] too. You are now God. Or possibly [[Series/DoctorWho The Doctor]].
7th May '16 4:27:50 AM ScorpiusOB1
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Right now there's no strict proof that such things exist: granted, there ''are'' heavy low-radiating objects ("black hole candidates"), but whether some low-emission star inside an enormous gas and dust cloud is really a black hole or not... Yet, there is one [[http://arxiv.org/abs/0903.1105 article]], that states: Sagittarius A* (a source of radio waves, associated with a supermassive object in the center of the Milky Way) must have an event horizon because, given the amount of superhot infalling matter we've detected around it, its surface luminosity is too low to be explained ''without'' something that traps radiation.

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Right now there's Until February 2016, with the [[https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves first detection of gravitational waves]] with the LIGO instrument[[note]]It has the bonus of having too proved the existence of black holes, since the detected signal exactly matches the theoretical predictions of a black hole merger[[/note]], there was no strict proof that such things exist: granted, there ''are'' heavy low-radiating objects ("black hole candidates"), but whether some low-emission star inside an enormous gas and dust cloud is really a black hole or not... Yet, there is one [[http://arxiv.org/abs/0903.1105 article]], that states: Sagittarius A* (a source of radio waves, associated with a supermassive object in the center of the Milky Way) must have an event horizon because, given the amount of superhot infalling matter we've detected around it, its surface luminosity is too low to be explained ''without'' something that traps radiation.
29th Mar '16 1:41:34 PM AnotherGuy
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Added DiffLines:

There is one last part about black holes that is still very controversial, the [[https://en.wikipedia.org/wiki/Black_hole_information_paradox Black Hole Information Paradox]]. That is, what ''happens'' to information when in a black hole. Hawking stated that it's irretrievably lost, which would violate the [[https://en.wikipedia.org/wiki/First_law_of_thermodynamics First Law of Thermodynamics]] - however, thanks to the bizarre nature of black holes, it's possible the law might be broken (thank you, infinity). Other theories include it being hidden in a "pocket universe" or it's released when the black hole eventually evaporates, regardless of its size.
9th Feb '16 7:45:44 PM DKN117
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Lighter stars become a degenerate-matter white dwarf which slowly cools over trillions of years into a black dwarf[[note]]Not to be confused with "brown dwarfs", which are substellar bodies, like large planets, that were never massive enough to sustain fusion to begin with.[[/note]]. According to current estimates, no black dwarfs yet exist, as a star cooling to that level would take longer than the universe has existed. The Sun is expected to become a black dwarf in approximately 1 quadrillion years. Stars with more than 1.4 times the mass of the sun have exceeded the "Chandrasekhar limit" and gravity combines electrons and protons to form neutrons, resulting in a neutron star. Stars whose mass exceeds the Tolman-Oppenheimer-Volkoff limit (about two to three solar masses, and definitely no more than five, but it's still unclear) are so massive that even the neutrons can't resist further collapse;[[note]]Neutron stars are prevented from collapsing further by a pressure called neutron degeneracy pressure. This is caused by the Pauli exclusion principle, and the degeneracy pressure is insufficient to prevent collapse over the Tolman-Oppenheimer-Volkoff. However, it is possible that there are other forms of degenerate matter, which may be capable of preventing further collapse until the object's mass reaches a new limit.[[/note]]it can be assumed that the star collapses down to the event horizon, and past it to a singularity (a single point, or a ring for a rotating black hole).

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Lighter stars become a degenerate-matter white dwarf which slowly cools over trillions of years into a black dwarf[[note]]Not to be confused with "brown dwarfs", which are substellar bodies, like large planets, that were never massive enough to sustain fusion to begin with.[[/note]]. According to current estimates, no black dwarfs yet exist, as a star cooling to that level would take longer than the universe has existed. The Sun is expected to become a black dwarf in approximately 1 quadrillion years. Stars with cores weighing in at more than 1.4 times the mass of the sun have exceeded the "Chandrasekhar limit" and gravity combines electrons and protons to form neutrons, resulting in a neutron star. Stars whose core mass exceeds the Tolman-Oppenheimer-Volkoff limit (about two to three solar masses, and definitely no more than five, but it's still unclear) are so massive that even the neutrons can't resist further collapse;[[note]]Neutron stars are prevented from collapsing further by a pressure called neutron degeneracy pressure. This is caused by the Pauli exclusion principle, and the degeneracy pressure is insufficient to prevent collapse over the Tolman-Oppenheimer-Volkoff. However, it is possible that there are other forms of degenerate matter, which may be capable of preventing further collapse until the object's mass reaches a new limit.[[/note]]it can be assumed that the star collapses down to the event horizon, and past it to a singularity (a single point, or a ring for a rotating black hole).
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