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Why the Black Hole Information Paradox Is Such a Problem
New submitter TheAlexKnapp writes: Here's a really nice explanation of the Black Hole Information Paradox for those who are unfamiliar with it. The article lays out the basic gist — that right now if you take two black holes, one made from the collapse of one type of star, and the second from the collapse of a different type, you can't tell which is which. Ethan Siegel points out that Hawking's big announcement was really just a small step heading towards a possible solution, and highlights that the paradox highlights the incompleteness of our understanding of some types of physics.
Leonard Susskind discusses this in a talk he gave a few years ago.
https://www.youtube.com/watch?v=2DIl3Hfh9tY
Pretty entertaining.
What if I make two different ice sculptures from the same source of water with the same mass but different shapes. After they melt it's impossible to tell which one was which. That's not a paradox.
Of course you are simplifying down to a ridiculous level, and I do understand that information is a pretty powerful concept in physics that carries a lot more weight than you would think, but still, I did not find anything useful in this article. The title of the Slashdot Summary was very promising: "why the black hole information paradox is such a problem", so I was hoping to finally see this question answered, but no, same old same old. Information gets conserved in all experiments we do outside black holes, so we kind of assume this must be some cosmic requirement (why?), and for some reason which is never properly explained we just can't accept that black holes would destroy information. Because... well, why exactly? Why is it such a problem that information would simply disappear in a black hole?
Why would it be such a problem if information did simply disappear? Oh my god, entropy might go down in an isolated system, it's the end of physics as we know it! No it's not. Entropy is just a trick that works because of the statistically enormously small probability of it going down in a large macroscopic system without spending energy on it, but isn't that really all it is? Why does it get treated like one of the most important truths in the universe?
Black holes are just a toy.
Suppose gravity wins out after all, and the universe ends in a Big Crunch. One or a few Planck second(s) before the singularity, all the information in the universe should still be there. How?
Suppose entropy wins and the universe ends in heat death. For bonus points assume all protons have decayed. All the information should still be preserved. How?
When the copyright term is "forever minus a day", live every day like it's the last.
For every unique cause is a unique effect. You can know what the cause was based on the effect. If the effect disappears, you can't know what the cause was. Anyway, if information is destroyed, that means the energy it represented is destroyed which means it cannot contribute to the mass of a system. It's contradictory to say the mass of a blackhole increases if the information is destroyed. A blackhole is created by too much information and it is itself a blob of information. The question isn't "why does a blackhole destroy information", but "what mechanism does a blackhole use to allow information to be recovered".
You and who ever modded up this post should do said reading. Quantum fluctuations, virtual or not, do not violate conservation of energy and do not make the universe any less closed. Work like QFT that takes these into account, producing some of the most accurate quantitative predictions ever in physics, basically show that what we see and measure already includes the effects of the vacuum, including on the microscopic level.