system
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human
Mass of the universe right after the Big Bang - why all this condensed mass not create a black hole?

Assuming the mass of the universe right after the Big Bang was equal to today's mass.... so much mass in such a small area, why was there no immediate black hole formation?
gpt
The universe was still infinitely big immediately after the big bang, just much much more dense. The universe was also *very* uniform and *very* hot. Because it was uniform, the gravitational acceleration on any point is basically zero. There were tiny fluctuations in density, but the universe was so hot that its pressure would just bounce these back before they collapsed. It was also so thick and opaque that it couldn't really radiate the temperature away from any point. It's only later that the universe cooled down enough to allow things to collapse into galaxies and stars and so on.