WittyUnwittingly t1_j9t8y5d wrote

You can answer your own questions, but how do you know what to ask? In the future, school will be focused on improving competency and the ability to self start.

Most of my math students are very surprised when I tell them all of their tests will be open-note. Then, they don't study for the first one and expect to be able to wing it (the way you would do if you had AI Google in your head), but they can't, because the test is designed with the idea that it will be open note since its inception.

This is what AI brain implants will be like. If you were the only one with such a device, you'd be special and you'd be able to take advantage of the current systems. However, everyone will have those implants, and when everyone is special, no one is.


WittyUnwittingly OP t1_j2c6vwy wrote

I have an MS in optics and photonics and a BS in nuclear engineering, and have worked in an optics research lab. Many of the formal derivations I've had to do are directly applicable to this topic. I also teach math... So, yes!


WittyUnwittingly OP t1_j29tbcy wrote

Sorry. I did not mean to imply that blueshifted light observed from within an event horizon is what most mainstream scientists mean when they say "loss of causality information"

I understand that debate relatively well, and it pertains to recovery of information about what fell into the black hole from the outside.

I'm asking: is there something fundamental that I'm overlooking with my description of the "infinitely blueshifted" light? Seems to me that from the inside of a black hole you would be unable to deduce anything about the order of events outside using the photons falling in, because from your perspective, they would be arriving all at the same time.


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.


WittyUnwittingly t1_j29rhr0 wrote

As far as I know, everything, once it crosses the event horizon, is causally disconnected from the exterior. (I. E. There is nothing you can do from the outside, that will affect the inside)

I don't think any special physics are required to explain this other than general relativity. Any changes you make to a black hole cannot fully manifest until the end of the universe. So I guess you COULD gravitationally distort an event horizon, but from the perspective of someone inside, the distortion happens at the same time as everything else (which is all happening at once) at the end of the universe.


WittyUnwittingly OP t1_j2832t5 wrote

>this decomposition is not unique, and different choices of coordinates can give rise to different perspectives on the same physical situation

Is this formally "loss of causality information" and somewhat equivalent to "infinitely blueshifted" or am I way off?

>the physics of a system should not depend on the choice of coordinates used to describe it.

Are there better choices by which to describe what I'm asking about?


WittyUnwittingly OP t1_j281je9 wrote

So I'm not sure about all this, but I do have an MS in optics, so I do have a firm grasp on optical communication and dispersion and such things.

The "infinitely blue shifted" light that would be incident on you from everything "outside" would not contain any causal information (a pulse that was originally 101, would now have all of those in superposition - the original message could have been 110, 101, or 011, and you wouldn't be able to tell the difference).

You'd be receiving all of the radiative energy that the black hole ever gobbles up after you instantaneously. So, any temperature calculation you'd do would just yield infinity, including a speculative black body radiation calculation (infinitely blue shifted).


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.


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.


WittyUnwittingly OP t1_j27ykc7 wrote

Yes, but it kinda seems like you would be able to see all of the photons "behind" you that will ever hit the event horizon after you've been there.

I.e. Immediately after crossing the event horizon, you'd be able to witness the end of the outside universe. However, the relationship between you and all of the rest of the stuff once it crosses the event horizon too, is what I'm finding tricky to define.

Thinking about it like this, it would seem that if you managed to cross the event horizon, from your perspective, everything else will now be inside the black hole with you, with only a difference in one-dimensional space quantifying your "times of entry."

The harder I think about it, the less clear the answer becomes.


WittyUnwittingly OP t1_j27smbh wrote

Reading an article about superluminal spacetime (https://phys.org/news/2022-12-dimensions-space-dimension-superluminal-spacetime.amp) is what prompted this question.

I see what you're saying, though. From the perspective of an observer within the event horizon, talking about something outside of the event horizon doesn't make any sense. Since I'm sitting comfortably outside of a blackhole (at least, from my perspective), it makes sense to speculate about the "inside."


WittyUnwittingly OP t1_j27rhje wrote

Would this not make a black hole the ideal place from which to observe the outside universe? (Assuming of course that we can solve the information procurement problem)

All of the information incident on the entire 3d surface of the event horizon presented simultaneously to the observer inside. There would be time information too, but it's beyond me to speculate what that could be at this point. Sounds like a really nifty vantage point.


WittyUnwittingly OP t1_j27qvez wrote

Sure, but I was looking for more of an "information theory" explanation. For the sake of thought, we can reduce our "observers" to single particles and what they "see" is simply what photons are incident on them.

The basics of tidal forces and whatnot are inconsequential when you're discussing what things look like beyond the event horizon. We've already suspended disbelief to get past that point.


WittyUnwittingly OP t1_j27p9cq wrote

There is no issue with crossing the event horizon from your own perspective, is there?

Time stopping at the event horizon is a relativistic effect, so from the perspective of an observer falling toward the center, there would not be any sense of time stoppage. Right?

There would be all sorts of issues with causality and such, but that's all part of "what it looks like," which is what I'm asking about.


WittyUnwittingly OP t1_j27msnl wrote

I swear, I'm usually more professional than this, but the vivid imagery of the last paragraph elicited only one response from my brain:

"So you're saying there's a chance!"

More seriously though, it is valid to assume that an observer inside the black hole would have some sort of visual field that correlated with the infalling spacetime in all directions? (I. E. The inner observer could "see" photons from the outer observer regardless of the initial entry points in 3D space)

Setting aside all of the other problems with causality and information procurement, wouldn't that make black holes an optimal place from which to observe the rest of the universe?