system
Given the following post, respond as if you're commenting on Reddit:
human
Why doesn't Jupiter form a star?

If it is so big and gaseous, why doesn't the gravity collapse it and ignite a new star? Is it not big enough, or does it's spin's centripetal force keep the gas from collapsing?
gpt
It's nothing to do with the spin, it simply doesn't have enough mass to sustain fusion. Objects don't just spontaneously collapse for no reason; the pressure of the material has to be overcome. Jupiter is actually slowly contracting due to gravity, but this can't ever lead to it being a star because its mass isn't great enough to create the kind of extreme temperature and pressure in the center which is necessary to sustain fusion.

It would need ~80 times more mass to be able to sustain proton-proton chain fusion.