> But also why did the Sun form at all?
I don't understand the question. There must have been a cloud of gas big and dense enough to provide the mass for the solar system.
Once that exists gravity does the rest, right?
> all the uranium we have on Earth came from such an event
That must mean the Sun also has its fair share of that Uranium? Or maybe more of it, since the heavy elements were more drawn to the center of the solar system?
>That must mean the Sun also has its fair share of that Uranium?
That's a good question. I would assume the sun captured a whole pile of uranium around the time the earth was forming. And it likely sunk to the core. The question is what happened then. The core area is dense enough to fuse hydrogen into helium, without any calculation I'd guess a lot of this is now in much smaller elements as there are a lot of neutrons to break it apart.
going on tangent here but Przybylskis Star might be relevant.
https://en.wikipedia.org/wiki/Przybylski%27s_Star#Chemically...
great rabbit hole, thanks :)
> I don't understand the question. There must have been a cloud of gas big and dense enough to provide the mass for the solar system. Once that exists gravity does the rest, right?
Very large clouds of gas can exist with gravitation attraction balanced by gas pressure. This delicate balance can be disturbed by passing stars, supernovae, galactic mergers and other events.