lack Holes are formed at the end of a High Mass Stars life. The greater mass of the star can compress the core so much that no amount of pressure can support it, and the star totally collapses leaving what astronomers call a black hole.

scape Velocity is the concept that applies to black holes. Escape velocity simply means the speed an object needs to escape the gravitational pull of another object. The larger the star the smaller its gravitational pull. When a stars mass becomes so compact that its escape velocity surpasses the speed of light then it is considered a black hole.

he theory of relativity shows that gravity is related to the Curvature of Space and a black hole is a place where the curvature is so extreme that a hole is formed.

homas Arny provides a great analogy to help illustrate the relationship between gravity and curvature: Imagine a waterbed on which you have placed a baseball. The baseball makes a small depression in the otherwise flat surface of the bed. If a marble is placed near the baseball, it will roll along the curved surface into the depression. The bending of its environment made by the baseball therefore creates an "attraction" between the baseball and the marble. Now suppose we replace the baseball with a bowling ball. It will make a larger depression and the marble will roll in further and be moving faster as it hits the bottom. We therefore infer from this analogy that the strength of the attraction between the bodies depends on the mount that the surface is curved. Gravity also behaves this way according to the general theory of relativity. According to that theory, mass creates a curvature of space, and gravitational motion occurs as bodies move along the curvature. Now we can extend this analogy to black holes by removing the bowling ball and replacing it with a steel safe. This will immediately rip the plastic and fall through. A marble placed on the torn surface will follow the safe into the hole and dissapear. So too a black hole is a "rip" in space where the curvature has become so strong that the structure of space has become disrupted.

he extreme curvature of a black hole prevents any light from escaping and for this reason its boundary is often referred to as the event horizon. All that happens inside a black hole is invisible to us forever. There is no radiation, rocket, spacecraft or anything else that can break free from its gravity. An object that emits no light is very difficult to observe, yet just as you can observe wind by the effects it has on its surroundings, so can astronomers observe a black hole. Black holes draw in gases which astronomers can see and thus prove that black holes do indeed exist.

tephen Hawking, the English mathematical physicist and cosmologist, was able to show that black holes can radiate. A black hole emits blackbody radiation. Because of this scientists were able to prove through Wien's Law that the temperature of a black hole is extremely cold yet not absolute zero. A black hole, like any other solar mass whose temperature is not absolute zero, emits energy in the form of electromagnetic waves. This energy is now called Hawking radiation. The radiation that escapes the black hole causes it to lose mass. Because the only source of energy available to the black hole is its mass, any radiation that escapes causes the mass to decrease. Therefore a black hole eventually dissapears in approximately 10⁶⁷ years. This is longer than the age of the universe, however this is important because it proves that even black holes evolve and die.