If the star is of a small to average size it will shrink down dramatically until it becomes a white dwarf – when the sun eventually becomes a white dwarf it will be about the size of the earth! A white dwarf has an extraordinary density – about one teaspoon taken from a white dwarf could weigh as much as a mountain!
The second possibility occurs if the star is very large. The star will throw out its outer layers in a terrific explosion, this is called a supernova. The star will then begin to contract under the force of gravity. But unlike the first possibility, this star will not be able to halt its collapse. The star will become smaller and smaller until it gets to the point where it has become infinitely dense and infinitely small – the singularity of a black hole.
A black hole consists of two main parts, a singularity and an event horizon. The event horizon is like the “skin” of a black hole, once you pass the event horizon there is no escape. The horizon is often referred to as the clothes of the black hole, as it is a barrier that separates the singularity from the rest of the universe. The event horizon can be seen by rays of light that are caught in a perpetual orbit around the black hole – unable to escape yet unable to fall in.
The singularity is what is found at the very center of a black hole; the singularity is a place of infinite density, infinite gravitational pull and where space and time are curved infinitely. Space and time as we know them cease to exist inside the singularity – when you near the singularity randomness reigns. Some physicist’s theorize that inside a singularity space and time are so warped that one becomes another – this means that escaping a black hole is impossible, as it is like trying to escape next Tuesday!
If black holes do not emit any light, than how come we even know they exist? The answer is that we don’t. But the way that black holes interact with other things can be observed. An example of this is in binary star systems (a binary star system is a star system that contains two stars orbiting each other). In these systems, if one of the stars collapses into a black hole, it will pull in the gas from the star that is orbiting it. This stream of gas can be seen from earth and can be used as evidence of a black hole.
Also, when black holes suck in gases that gases swirl around the black hole before they actually get pulled in (this is called an accretion disk) if the speed of the rotation of the black hole can be measured then so can its weight. If the spinning body has a large enough weight than you can be pretty sure that it is a black hole.
First, as you neared the even horizon, time would appear to take longer and longer and as you entered the even horizon your image would remain there for an eternity. This is because at that very moment, the light that you are emitting would be caught in the event horizon. It would appear to an observer that you were frozen in time, staying in the same position forever. But in fact it is just the light, not you that is stuck. As you entered the black hole time would go faster and faster, and if you looked up you would be able to see the entire universe evolving in front of you. But this amazing sight comes at a great cost, as you begin to near the singularity you would feel your body begin to stretch. Eventually your body would be stretched so far by the colossal gravity that you would be ripped apart!
