Question: What's at the bottom of a black hole?

Robert Hampson answered on 17 Nov 2014:

A black hole is essentially a massive star which at the end of its life has collapsed under the force of it’s own gravity becoming so dense that its gravity crushes itself to a tiny little particle called a singularity. We have not observed the inside of a black hole so we are not sure if the singularity still exists pur se. We cannot observe it because anything that goes in, cannot come out again even light and radio waves cannot escape the gravity of a black hole.

The universe sits within something called space-time. This is everywhere, its like the paper which you draw a picture on, its not really part of the picture, but without it the picture wouldn’t exist. Masses like planets or suns slightly bend space-time theoretically causing gravity. It is as if space were a rubber sheet, and a planet was a marble you put on it, it would cause a dip in the rubber sheet. Other marbles would then want to run into the dip. Planets do the same kind of thing to space time. A black hole is strange because it has incredibly strong gravity and bends space time more than anything else. If you entered it you would be stretched along with the stretching of space. The distance between your head and feet would increase (you probably be dead by now anyway). Once you cross the point where even light cannot escape (called the event horizon), the equations for space and time and location start to have multiple solutions which means that upon entering a black hole you could theoretically be in two places at once. There are also theories that suggest black holes could tear space time or strangely create bubble universes (like small sheres of space-time under the existing rubber sheet.

Needless to say this all sounds quite weird and it can’t be tested or observed it isn’t really “science” either. However, these are the best guesses of our physicists at the moment.