Why was the universe right after the big bang not a black hole?

Question

When the age of the universe was - say - equal to Planck time, it was obviously below Schwarzschild's radius. Then why didn't it collapse back under its own gravity as any well-behaved black hole? I thought only Hawking's radiation could escape a black hole. In this case a whole universe did!

Answer 1

If the Universe were a little more dense, it would have collapsed immediately after the Big Bang. This is not exactly the "Black Hole" Schwarzshild solution to Einstein's equations, but the "closed Universe" Friedmann solution. We seem to actually be in an "open Universe" (or perhaps marginally closed) Friedmann solutoin. This differs from the "Black Hole" solution in that space is filled with a uniform fluid of relatively low density. Of course this fluid becomes increasingly dense as we look back toward time zero, but at any positive (non-zero) time the density is finite. A Black Hole solution has an infinitely-dense singularity.

But your question is really fundamental---why should the Universe have the "finely tuned" density that allows it to survive for many Planck times (in fact, more than 10^45 Planck times). One answer is the anthropic principle: if it weren't so, we wouldn't be here to see it. Another is early inflation: if the matter in the Universe was actually created by a change in the energy of a false vacuum, then it would naturally be of the correct order.

Answer 2

It was a black hole from another universe. That blackhole seperated just as a water dropplet seperates from a moist surface. The very instant it seperated from the universe it flew apart as there would no longer be any gravity to hold it together. All the energy that was being held together with the massive gravity is now flung out.

At the moment of seperation there wouldn't be any gravity because it contained all the space of space. Imagine putting a 10 ton object on a matress and the heavy object is the same shape of the matress. When you lay the heavy object down the matress will just compress, it wouldn't create gravity. Unlike if you put a bowling ball on the matress it will deform the matress and cause things to roll towards it.

Answer 3

If a black hole is a frozen star that means that there had to be a star before a black hole could exist.
Black hole are not 100% frozen so heat radiation can still eminates..It has not been determined that a perfect black hole exist.
The Big bang Universe is One that was presumed by scientific formula. We are not sure that it represent the actual construction of the Universe.