Xethinus t1_j27xzlx wrote
So... im happy to give this a try. I'm happy to be corrected if there are better guesses.
Let's assume an observer can survive all the effects of a black hole, and can "see" in every direction.
In the up direction, the observer sees the rest of the universe pass in an instant, blue shifted to numbers that don't make sense for any physical model.
In every other direction, nothing.
Space and time have swapped places, and you can time travel now, but you can only travel in one direction through space, and it's down. Same goes for every photon. Down. It can't orbit anything, can't go sideways. Only down. The observer on the other side have the same problem. You might get a glimpse of them just before you both pass the event horizon, but now, it's only down. Your worldline, just as it was always pointing forward in time above the horizon, will always point down below it.
You can't see what's below, as photons are only traveling in one direction at this point, and can't go up to meet the observer above.
I have a theory that an observer wouldn't even make it that far, as hawking radiation would annihilate anything that just passed the event horizon immediately from its own perspective. This would be because an indefinite amount of time passes on the outside to produce hawking radiation, giving no time at all to an internal observer to get very far past the event horizon. This may be a cosmic necessity, given the extreme nature of black holes.
Edit: I think this is my first gold! I don't know what that means yet, but thanks!
WittyUnwittingly OP t1_j27zdpk wrote
>hawking radiation would annihilate anything that just passed the event horizon immediately from its own perspective
This is perhaps the most interesting point I've read all night.
Thinking about an observer's "perception" from within a black hole circles me back to all of the same problems we have with time/FTL travel, which makes sense.
An observer from "inside" a black whole should be able to perceive all of the photons arriving at the event horizon after they did simultaneously, but "infinite blue shift" should imply that any causality information would be lost (Think of a binary pulse... Physically, a 1 would be unable to arrive before a 0 or vice versa)
Yeah man... That makes total sense, because from the perspective of the observer falling in toward the black hole, they would arrive at the singularity at the same instant that it evaporates due to hawking radiation at the end of the universe. This fits very neatly with some of the other "causality protection" conjectures.
Xethinus t1_j2806q2 wrote
Oh. If you keep my amateur theory consistent, there is no actual singularity. Any nothing would ever approach it.
To the observer, all of this happens at the same time, while they pass the event horizon. The center of the black hole would take an infinite amount of time to approach.
Black holes are really annoying, because most of their calculations result in "undefined" or "zero" and there's not much in between.
WittyUnwittingly OP t1_j280ddz wrote
Well, you can use the word "annoying" if you'd like, but I would call it a rather elegant reconciliation of a lot of the problems I was having.
For example, if one were to have a mastery of mechanics such that they could dip in and out of an event horizon, how could there be any continuity of what they perceived versus what they did? No need for any of that with this explanation, because it necessarily cannot happen.
superVanV1 t1_j2952g4 wrote
not unless we achieve FTL travel.
though under current models of acheiving that via the warping of space, sticking a spacetime bubble into a spacetime singularity may cause "issues"
WittyUnwittingly OP t1_j29s599 wrote
Well, even if you took an Alcubierre drive into a singularity, once you get there, there would be no path you could choose to get back out, regardless of what speed you can go. Even if you could somehow distort space enough to "get back," when would you arrive? At the end of the universe?
Seems like your best bet for something that can go into and come out of blackhole, is something that does not obey the normal laws of causality, and can come out of a black hole before it goes in.
superVanV1 t1_j2a3qxv wrote
Which we have no way to model for, since current mathematics still just returns a big ‘ol error sign when trying to calculate beyond the event horizon. It’s entirely possible that physics just.ceases to operate properly at that point
kclongest t1_j2acvn9 wrote
Y’all just made my brain splode
superVanV1 t1_j2adwex wrote
Yeah, fringe physics tends to do that
Kevskates t1_j2c1vse wrote
All this talk of the limits of physics make me feel like we’re in a video game trying to explain the invisible edge of the map
paloprint t1_j2cbew3 wrote
Like when McConaughey touched hands with Brand. Corny I know. He’s was going out they were going in.
wokeupatapicnic t1_j2brwdu wrote
Pretty sure you just described the Firewall theory. I think Hawking proved that or at least was able to suggest that, this is not the case, but it’s worth looking into on your own if you’re interested!
WorstMedivhKR t1_j2apghs wrote
This is what actually falling into a simple Schwarzschild black hole would look like. The physicist behind this, Andrew Hamilton, also has some for more realistic types of black holes but they are harder to understand. Notice that locally nothing special happens when crossing the "true" event horizon, and there is still an outside view of the universe. The only way you get a tunnel effect upward with darkness in every other direction is if you use a great deal of energy just outside the true event horizon to accelerate against the gravity of the black hole.
The ending of this video is hitting the singularity.
lawblawg t1_j2apya0 wrote
So you’re quite correct on almost everything, except for the bit about being annihilated by Hawking radiation. This is the firewall problem. The event horizon cannot be defined objectively in general relativity; rather the event horizon is defined relative to an observer at a specified location. That’s because if the event horizon was a defined location, it would dictate a universal reference frame, which violates relativity.
So the event horizon cannot be accompanied by a firewall of deadly Hawking radiation. The currently accepted solution is that Hawking radiation is emitted from quantum fluctuations which are not only uncertain in energy but are also uncertain in location. And those fluctuations are redshifted or blueshifted relative to the observer, and so relativity is preserved.
cbusalex t1_j295xdr wrote
> You might get a glimpse of them just before you both pass the event horizon
At the very least, you'd see them (well, a very distorted image of them) at 90 degrees left and right as you cross the photon sphere.
piousflea84 t1_j29tbq7 wrote
Is this the “firewall hypothesis” of everything inside a black hole piling up in an infinitely hot infinitely thin surface just inside of the event horizon?
[deleted] t1_j29wets wrote
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