General relativity predicts that time ends inside black holes because the gravitational collapse squeezes matter to infinite density.
Proof of the black hole is a tremendous amount of mass inside a very small volume. There's 4 million times the mass of our sun within a region that's comparable to the size of our solar system.
When you fall into a black hole you will be literally spaghettified.
The key to proving that there's a black hole is showing that there's a tremendous amount of mass in a very small volume. And you can do that with the motions of stars. The way the star moves around the center of the galaxy is very much like the way the planets orbit the sun.
A big misconception is that a black hole is made of matter that has just been compacted to a very small size. That's not true. A black hole is made from warped space and time.
We see no objects in our universe that could become wormholes as they age.
The key to proving that there's a black hole is showing that there's a tremendous amount of mass in a very small volume. And you can do that with the motions of stars.
I became interested in this question of whether you can build wormholes for interstellar travel. I realized that if you had a wormhole, the theory of general relativity by itself would permit you to go backward in time.
Only black holes of very low mass would emit a significant amount of radiation.
Wormholes - if you don't have something threading through them to hold them open, the walls will basically collapse so fast that nothing can go through them.
There are no black holes - in the sense of regimes from which light can't escape to infinity. There are however apparent horizons which persist for a period of time.
