I'm watching some PBS Space Time videos. Specifically the playlist about neutron stars. They seem to get overlooked in popular media, being figuratively outshined by their more glamourous black hole siblings. But there's something so wild and wonderful about a star that's effectively a single massive atom.

Also, in physics there's a concept called the Schwarzschild radius. The short version is that if you pack an amount of mass into a space smaller than that radius for that given mass, you've created a black hole. Now here's the crazy part: if the estimated amount of mass in the universe is put into that equation, the Schwarzschild radius is about three times larger than the estimated size of our universe. In other words, we may be living on the interior of a black hole, and that black hole may have been created by a collapsing star in a parent universe. Of course there's no way to test this, so it's not remotely a scientific theory, but more of a "cool idea while high" thing. And it's mathematically fun to think about.