5 ms·

While from a human perspective information seems to be being destroyed, really it's just being obfuscated beyond our means of recovery. If you were to pause ti

While from a human perspective information seems to be being destroyed, really it's just being obfuscated beyond our means of recovery. If you were to pause time, with enough analysis and knowledge of the present state of your burning parchment you could recover the state from a split-second prior to that. No-hair theory says that the event horizon of a black hole is different. One moment the information exists, the next moment it's just gone.

akiselev 11y ago
This is a key point: recovery of the information requires some knowledge of time. If you were handed a pile of ashes (assuming ideal combustion of every molecule) you have zero chance of recovering any information but if you watched it burn, you can theoretically recover the initial state. Thats where the analogy breaks down with black holes: when a singularity absorbs a particle not only is any information about its identity lost, but also where it was in time. If you were to mix a bunch of ashes after watching several different documents burn you could still recover the initial state of each one but because of the extreme conditions in a singularity, even this basic axiom of cause and effect is no longer valid.
- SilasX 11y ago
  So black holes really do shrink phase space, and it's not simply a matter of it being too computationally expensive to extract out "what went inside it" given the microstate of the black hole radiation?
  - akiselev 11y ago
    Yep. The big unanswered question as far as I know (from a layman's perspective) is whether the matter/energy in the singularity at the center of a black hole even follows the laws of nature as we have observe them or if all of that is out of the window past the event horizon. If you don't know the laws of nature describing what happens inside (and you can't study them due to the destructive nature of those forces), no amount of computation will be able to help.
- richmarr 11y ago
  > handed a pile of ashes... you have zero chance... I think I may disagree with you on the parchment, and think I agree with you on the singularity... but it's hard to tell for sure because we're all throwing half-cooked analogies around and it's been a long day. (disclaimer: I am a physicist)

akiselev 11y ago

This is a key point: recovery of the information requires some knowledge of time. If you were handed a pile of ashes (assuming ideal combustion of every molecule) you have zero chance of recovering any information but if you watched it burn, you can theoretically recover the initial state. Thats where the analogy breaks down with black holes: when a singularity absorbs a particle not only is any information about its identity lost, but also where it was in time. If you were to mix a bunch of ashes after watching several different documents burn you could still recover the initial state of each one but because of the extreme conditions in a singularity, even this basic axiom of cause and effect is no longer valid.

SilasX 11y ago
So black holes really do shrink phase space, and it's not simply a matter of it being too computationally expensive to extract out "what went inside it" given the microstate of the black hole radiation?
- akiselev 11y ago
  Yep. The big unanswered question as far as I know (from a layman's perspective) is whether the matter/energy in the singularity at the center of a black hole even follows the laws of nature as we have observe them or if all of that is out of the window past the event horizon. If you don't know the laws of nature describing what happens inside (and you can't study them due to the destructive nature of those forces), no amount of computation will be able to help.
richmarr 11y ago
> handed a pile of ashes... you have zero chance... I think I may disagree with you on the parchment, and think I agree with you on the singularity... but it's hard to tell for sure because we're all throwing half-cooked analogies around and it's been a long day. (disclaimer: I am a physicist)