Question

Why didn’t the Universe collapse into a black hole in the past when there was so
much matter in such a small space?

(a) Most of the particles in the early Universe were unstable and decayed before a black
hole could form. By the time only stable particles were left (protons, electrons, etc.),
the Universe had expanded to be large enough so that it would not collapse into a black
hole.
(b) Quantum gravity—which is relevant at high energies and small distances—stabilized the
Universe and prevented a collapse into a black hole.
(c) Particles in the early Universe had a lot of kinetic energy (the temperature was very
high!), preventing them from becoming gravitationally bound and collapsing into a black
hole.
(d) It actually could have collapsed into a very giant black hole that we are now living inside
of.

Answer 1

c) universe is rapidly expanding with very high speed and temperature thus it didn't collapse into a black hole. The Schwarzschild solution of the gravitational equations is static and demonstrates the limits placed on a static spherical body before it must collapse to a black hole. The Schwarzschild limit does not apply to rapidly expanding matter.

Answer 2

Nice try to solve the final exam of course of profesor Murayama...

Answer 3

I agree with you Anonymous...Gwerty-think!!!!