So, as usual, I don't fully get GR and black holes, but then what else is new? This time it's about black holes destroying information. And I'm probably understanding it awfully wrong, because it seems to me like black holes actually CREATE information.
I get the general narrative. Matter goes in, carrying information, random Hawking radiation comes out, which doesn't carry that information any more. Seems straighforward enough...
... until I start thinking, "well, in which chart/frame does that happen?" The aforementioned narrative almost invariably leaves that out. Well, I like things more rigorous than that.
So I'm thinking, ok,
- first, how it looks to a distant observer outside the black hole. (By looks to, I mean, I'll put my frame of reference there. Like, my frame is on Earth and I'm observing Sagittarius A* somehow.)
Well, in my chart, the old information is never actually gone. Whatever object I'm observing falling into the black hole, it never actually crosses the event horizon. Even the oldest information that ever collapsed into a black hole, like the big bang photons that went into a primordial black hole, technically it's still there, plastered on the surface of the black hole's horizon, just 1 planck unit outside it.
Sure, it gets infinitely far away, so to speak, and infinitely red-shifted, so I can't actually observe it in any meaningful way, but things don't disappear if you stop being able to observe them. The sun doesn't actually disappear during an eclipse, for example.
So the old information is still there. The Hawking radiation is extra information coming out of the black hole. It's not replacing the old information, it's adding to it.
- from the point of view of the thing that just fell into the black hole.
Well, as long as I didn't yet hit the singularity, my information is still there. However, as soon as I crossed the event horizon, I start seeing the other half of the Hawking radiation. Those particle-pairs still form near the event horizon, and one goes out, the other goes inwards with me. Some of it is BECAUSE of me, since the black hole just got a wee bit bigger because of my mass adding to it, so that's extra particle pairs caused by my being in the black hole. That's also additional information.
So, like, what am I understanding wrong there?
I get the general narrative. Matter goes in, carrying information, random Hawking radiation comes out, which doesn't carry that information any more. Seems straighforward enough...
... until I start thinking, "well, in which chart/frame does that happen?" The aforementioned narrative almost invariably leaves that out. Well, I like things more rigorous than that.
So I'm thinking, ok,
- first, how it looks to a distant observer outside the black hole. (By looks to, I mean, I'll put my frame of reference there. Like, my frame is on Earth and I'm observing Sagittarius A* somehow.)
Well, in my chart, the old information is never actually gone. Whatever object I'm observing falling into the black hole, it never actually crosses the event horizon. Even the oldest information that ever collapsed into a black hole, like the big bang photons that went into a primordial black hole, technically it's still there, plastered on the surface of the black hole's horizon, just 1 planck unit outside it.
Sure, it gets infinitely far away, so to speak, and infinitely red-shifted, so I can't actually observe it in any meaningful way, but things don't disappear if you stop being able to observe them. The sun doesn't actually disappear during an eclipse, for example.
So the old information is still there. The Hawking radiation is extra information coming out of the black hole. It's not replacing the old information, it's adding to it.
- from the point of view of the thing that just fell into the black hole.
Well, as long as I didn't yet hit the singularity, my information is still there. However, as soon as I crossed the event horizon, I start seeing the other half of the Hawking radiation. Those particle-pairs still form near the event horizon, and one goes out, the other goes inwards with me. Some of it is BECAUSE of me, since the black hole just got a wee bit bigger because of my mass adding to it, so that's extra particle pairs caused by my being in the black hole. That's also additional information.
So, like, what am I understanding wrong there?
via International Skeptics Forum https://ift.tt/2Qo87dY
Aucun commentaire:
Enregistrer un commentaire