Now, a bit of a thought about black holes. If nothing can come out, then it doesn't seem right that anything can go in, either...
If light cannot can escape a black hole, then nothing can, as no information can escape. If nothing can escape a black hole then its volume is essentially nothingness, the edge of the universe itself. If so, nothing can enter a black hole either, such that all things would be deflected to spin around its event horizon, tantalisingly spiralling towards an infinitely close relationship with the hole, the nothing, the edge of the universe.
If this were the case then black holes could never grow, it seems, although black holes can radiate and shrink, burning off their gravitational energy. Perhaps their size can grow, but only their radius, as all matter and energy would be on the periphery of these bodies, nothing inside. It would be the radius, the surface that would grow or shrink. An analogy for this would be a bubble, which can grow or shrink, but it is the radius which is made of the bubble-stuff that grows, not the air inside (which in our example, is nothingness).
The edge would hold all of the mass too. The space inside wouldn't exist, and when the black hole was formed, all of the mass would have been pushed to the outer edge where it would forever remain.
There would be nothing beyond the event horizon, and no possibility of things falling into it, just a scatter of energy at its border. This shell can grow and shrink, appearing as if the hole in the centre was growing and shrinking, but it would be the shell that changes in mass and size.
This vision reminded me of the early universe. If a black hole, the sphere of nothing, is the edge of the universe, then it could have been there during the big-bang. Perhaps, when the universe expanded, it expanded with a hole at its centre, like a black hole. This would be nothing, so undetectable. What we know as the universe would instead be a spherical shell in shape. This is of course, a well considered possibility already but I'll explore this idea a little.
What implications would this have? How would a smoothly expanding universe in three dimensions differ from a similar one but wrapped onto the surface of an expanding sphere?
All things would appear in the same way in terms of the type of expansion. Each galaxy or other object would move apart evenly from each other.
For each net increase in expansion, the size of the universe would increase by the surface area of a growing sphere.
This would be a wrap-around universe, so we could see ourselves distantly, just as we can wrap around the Earth and reach ourselves again. Constraints related to the speed of light, the detectable edge of the universe may limit the possibilities to test for this.
