HN Theater @HNTheaterMonth

PBS Space Time to the rescue:

What Happens at the Event Horizon? - https://www.youtube.com/watch?v=mht-1c4wc0Q

What’s On The Other Side Of A Black Hole? - https://www.youtube.com/watch?v=T4oYvSH6jJ8

How Time Becomes Space Inside a Black Hole - https://www.youtube.com/watch?v=KePNhUJ2reI

The Black Hole Information Paradox - https://www.youtube.com/watch?v=9XkHBmE-N34

⬐ tzs

I'd recommend the two episodes released right before the one about the black hole information paradox too. They set up for what is covered in the information paradox episode.

"Why Quantum Information is Never Destroyed" - https://www.youtube.com/watch?v=HF-9Dy6iB_4

"What Survives Inside A Black Hole?" - https://www.youtube.com/watch?v=GscfuQWZFAo

Maybe the episode before those two also. I vaguely recall that something from the information paradox episode used something from that (and if I'm misremembering, it was still a neat episode):

"Noether's Theorem and The Symmetries of Reality" - https://www.youtube.com/watch?v=04ERSb06dOg

I have a question about the episodes you cited. They cover how beyond the event horizon space becomes time and time becomes space. They go over how that means that inside you can't go backwards in space for the same reason that out here in the normal universe you can't go backwards in time. You are doomed to only go forward, which inside means toward the singularity.

(Much better than the ridiculous analogy often given that you can't get out of a black hole because the escape velocity equals or exceeds the speed of light. That's a ridiculous analogy because it only explains why you can't get out ballistically).

But all their explanations used a simplified black hole in a spacetime with just 1 space dimension and 1 time dimension. We've actually got 3 space dimension. Does that mean that in a real block hole past the event horizon, you end up in a spacetime with 3 time dimensions and 1 space dimension?

If so, does anything interesting happen due to having more than one time dimension?

⬐ neom

I think that's the million dollar question. :)

This episode touches on that a bit (but not really), and we're getting into holographic universe theory - https://www.youtube.com/watch?v=klpDHn8viX8

https://www.youtube.com/watch?v=mht-1c4wc0Q

I hope it helps. I think this is the cleanest explanation with actual visual representation.

Edit: Sorry this one is even better.

How Time Becomes Space Inside a Black Hole | Space Time

https://www.youtube.com/watch?v=KePNhUJ2reI

The particle goes through the event horizon in finite time according to its own clock (and will then hit the singularity in finite term however it tries to travel).

Think of the view of it by an external observer as being 'frozen' at the event horizon as kind of optical illusion caused by the extreme warping of spacetime. For a non-evaporating black hole (as described by general relativity), the 'last' photon coming off it will indeed be at infinity (or with infinite redshift). If (when) the black hole evaporates, the external observer will see that and of course there will be no more photons from the infalling particle.

These two different views are hard to reconcile from our human perspective of how the world works, but they really do come from the mathematics of general relativity.

Here's a really excellent and short video which attempts to explain this in ten minutes. (His explanation of how a Penrose diagram works is fleshed-out in more detail in the Susskind lectures I mentioned above).

PBS Spacetime - What happens at the Event Horizon

https://www.youtube.com/watch?v=mht-1c4wc0Q