Timeline for Why can't the information inside a black hole be reconstructed from what's left outside?
Current License: CC BY-SA 4.0
11 events
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| Feb 28, 2022 at 4:38 | history | edited | Níckolas Alves | CC BY-SA 4.0 |
Fixed typo
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| Feb 13, 2022 at 13:11 | comment | added | Níckolas Alves | @PeterMortensen I can't watch the video right now, but the no-hair theorems of General Relativity show that a (stationary) black hole is characterized by only mass, charge, and angular momentum. In classical GR, the temperature of a black hole is always zero (it can't emit anything). When some quantum effects are taken into account, it gets a non-vanishing temperature due to Hawking radiation, but this temperature is completely determined by the black hole's mass, charge, and angular momentum. | |
| Feb 13, 2022 at 13:08 | comment | added | Níckolas Alves | @erikm Precisely. The paradox is exactly that one would expect information to still exist out there somehow. Yet, it doesn't. I should point out that not all scientists agree this is indeed a problem (there are respected researchers, such as Robert Wald and William Unruh, who believe it is just a cool prediction of quantum theory). This is still the object of discussion in Physics (welcome to the edge of human knowledge!) | |
| Feb 13, 2022 at 11:35 | comment | added | Peter Mortensen | There is a fourth property for black holes: temperature/pressure | |
| Feb 13, 2022 at 7:13 | comment | added | erik m | ...but as I understand the aim of your second anecdote, the knowledge of what the star is made of is embedded only in its matter, with no consequence to the outer world. Thus this knowledge could potentially be lost when the star collapses into a black hole. | |
| Feb 13, 2022 at 6:35 | comment | added | erik m | It might be that some of my confusion comes from a more outdated philosophical notion of information: to claim that information is 'lost', it must at some point have been 'known' by the universe, and that this knowledge would still exist out there in some form. | |
| Feb 13, 2022 at 6:32 | comment | added | erik m | Thanks again for your answer. Yes, I don't doubt that the mathematical arguments for this are solid, and you're right to assume that I wouldn't understand them. Therefore I tend to examine these thought experiments in a more literally way than they were designed to be. | |
| Feb 13, 2022 at 0:41 | comment | added | Níckolas Alves | @erikm Excellent remark. That is, however, a failure of my anecdote, since it is particularly complicated to mimic the math without, well, the math. I edited my answer to try to address that point, please take a look at the new version =) | |
| Feb 13, 2022 at 0:39 | history | edited | Níckolas Alves | CC BY-SA 4.0 |
added 1612 characters in body
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| Feb 12, 2022 at 21:48 | comment | added | erik m | Thanks for a clear and thoughtful answer. Would I be wrong to say that in your anecdote, for the information of the lost balls redness to have existed, there must also exist light? And in principle, after the ball have disappeared, the red light reflected from the ball can be hunted down and observed? I'm trying to understand how one can think about information having existed, without it in some way making manifest and leaving an imprint in the universe. | |
| Feb 12, 2022 at 20:59 | history | answered | Níckolas Alves | CC BY-SA 4.0 |