Planet and singularity

[Hyperreality]

Why does physicist only talk about gravity collpase on stars?

Doesn't gravity collapse happen to planets? I mean they do not have any process such as nuclear fusion do repell gravity.

[Tail]

I would imagine the mass of planets is much too small. After all, gravity is a very weak force.

[jcsd]

Tail is correct, the mass of a planet is far, far too small for gravitational collapse to occur IIRC the minimum mass of a star (befiore going supernova) needed to create a black hole is thought to be in the region of 20-40 solar masses (i.e. 20-40 times the mass of our sun).