Shawn Ryan

So basically, I think a lot of people would believe, OK, when you first go through, you don't really know that you went through because the black holes can be different sizes, right?

And so if it were large enough, the curvature scale when you're crossing the horizon isn't so extreme.

But eventually, if you just did little probes on this background, I think people talk about spaghettification or you're going to be stretched out eventually when you get closer to where the curvature is larger and blowing up at the singularity.

But I think that's a funny thing is people

Like, you understand this classical geometry, and then you start having problems putting quantum fields on it and answering some fun, like, paradoxical type of questions that then people aren't sure, like, they think that the singularity is something so highly curved that the approximation of just treating it classically is bad now, so then they don't know what happens if type of thing.

But it's not, like, I think it's easy enough to try to say, okay, if I, like, have some nice numerical simulation,

And I can just write down this differential equation for how something would propagate on a classical black hole background, that you could have something just going through the horizon for a little bit.

And probably in that model, it looks fine.

But it's just like, how valid are those?

How hard is the numerics, first of all, to do near certain regions?

And the way you set up for a scattering process probably is also hard.

But basically, the problem is that sometimes it's the question you're asking ends up being not the right question or things like that type of problems.

No, I mean, so, but it's basically like you're writing, like, how do I say it?

So like you have this metric is telling you like the, if I have a coordinate system for my space time and I have then a notion of like the distance between points on it and like a nice coordinate system is often some notion of like a spherical coordinate system where, okay, like very far away, I have this like, you know,

directions in the night sky, and let's say a time direction in this case.

And then in that coordinate system, there's a solution to this differential equation that Einstein gives you where you don't have any matter sourcing outside.

And it ends up being a black hole solution where there ends up being a horizon.

And you can just kind of play around with how does the energy redshift or whatever, things like that.

It's very much just a math problem.

You know what I mean?