Visualizing Black Holes with General Relativistic Ray Tracing
It's a general relativistic ray tracing renderer simulating a Schwarzchild black hole and its accretion disk, written in HLSL shader language and run in Unity with C#. There's that jargon! Let's break down each of these terms: [...]
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Ah, fun! I'd just recently caught up with a Stand-up Maths video from a couple years ago which is about general relativity and dives into this topic a bit, too. Some fun stuff in here: https://www.youtube.com/watch?v=Z4oy6mnkyW4 - That video's got an interview with Eugénie von Tunzelmann who'd worked on the black hole raytracing stuff for the movie Interstellar (including some talk about what was intentionally left out for cinematic reasons), and was credited in this paper about it: https://arxiv.org/abs/1502.03808
This gives me a POV-Ray boner.
This is relevant to my interests.
ObNiggle: it's Schwarzschild. (Think shield, not child).
I'm not sure why he talks about how massive the object is in the videos: it almost certainly doesn't matter. The Schwarzschild solution itself just scales with mass (event horizon radius is 2M in geometrical units), so you can't tell if you are looking at a very massive object from far away or a less massive one from closer. If you want to deal physically with accretion disks I think you do care about the mass because tidal effects become less for larger objects as the scale of the curvature becomes large compared to the effective scale of the forces which hold objects together (this is basically the same thing that tells you why rocks are rock-shaped but planets are spheres). But I'm sure he's not doing that (because doing that would definitely need a supercomputer I think).
Perhaps what he means is that the animation is showing you how fast things like the accretion disk would appear to move from the perspective of an observer and he's scaling that right?
It's impressive though!