Black holes are the evolutionary end to a massive star. Although it is hard to imagine , a black hole comes directly from a star. Stars come from dust and gas in the atmosphere , that heat up and start giving off radiation. These are known as protostars. A protostar will brighten and continually contract and rise in temperature. As the temperature increases the pressure increases which brings you to a point where the outward force balances the inward force of gravity. The dust soon vaporizes, and the gas turns opaque. Black holes are formed when a massive star or supernovae ends it s life. The process where the star evolves and then dies is called stellar evolution. At the end of a stars life it is involved in a supernovae explosion. This explosion burns away the elements in astar except for the iron core because as we know iron cannot burn.

When the iron core reaches a certain mass, a sequence of events is triggered. Gravity over rules the pressure that had been stabilizing it, and the iron core collapses. The core goes from the size of about five thousand miles to the small size of about twelve miles in less than a second.. At this point the star has reached singularity. Singularity is when a star is compressed to a point of zero volume and infinite density. The matter is squeezed until it occupies no space but is still technically there. Singularity is the center of the black hole that is surrounded by the event horizon. The Radius of the event horizon is called the Schwarzchild radius of the gravitational radius.. To find the radius of the event horizon you use a specific formula. R=2gm/c, is used with c as the speed of light, and g as the universal gravitational constant. The gravitational radius and the mass are directly proportional to each other. It you had a black hole with the same mass as the sun it would have a radius of three kilometers, If you had a ten solar mass black hole the radius would be multiplied by ten and the radius would be thirty kilometers. For a mass as small as humans, the gravitational radius would be smaller than the nucleus of an atom.

The amount of energy released during the collapse is equivalent to the amount of energy released by one hundred stars in their ten billion year lifetimes. This amount of energy is extremely enormous, and most of it is sent into space by particles called neutrinos. A very small amount of this energy is sent into the envelope enclosing the star, and it causes the envelope to explode The energy deposited on the envelope creates an incredibly strong shock wave. As the shock waves go outward they heat up the envelope and induce explosive nuclear burning that ejects the envelope at about ten million miles per hour. The result of these event s leave a compact stellar remnant. This remnant is a neutron star or black hole. Only the most massive stars become black holes. The rest become less compressed bodies which are either white dwarfs or neutron stars.

White dwarfs and neutron stars cool off and slowly fade and become invisible. It is much different for black holes because they are invisible from the start. Since black holes came from massive stars, it has an intense gravitational field that keeps light from escaping. In order for an object to escape a black hole it would have to be moving faster than the speed of light. Because of this black holes cannot be seen which make them incredibly hard to detect.

Since we cannot se a black hole we must find other ways of detecting them. A black hole attracts matter, and although much of the matter is sucked into the black hole some is left orbiting around it. This matter forms an acctetion disk which heats up as it orbits at a high velocity around the black hole. The gas soon starts to radiate and give off x rays. These x rays are our key to detecting black holes. Using these rays, we can detect where the starting place of the x rays are.

There is no limit to the size of a black hole , any amount of mass if you compress it to a certain density can become a black hole. If the conditions were right the sun could be a possible candidate to become a black hole. A typical black hole would have the mass of about10^31 kg, And there are others with about 10^ 37 kg.

In 1994, the hubble telescope proved that there is a supermassive black hole in the center of the m87 galaxy. It s mass is equal to about two or three billion sun s, however it is still not as large as out solar system. Scientists also believe that there is another large Black hole in the center of our own milky way galaxy. The most intriguing type of black hole are the mini black holes. These black holes were supposedly created during the big bang, and eventually will lose all its mass and fade away.

Black holes are filled with many natural phenomenon s , gravity crushes and forms it. Light makes them so unusual, and stars begin the life of a black hole by the death of their own. When combined together these factors create black holes in our universe. No one knows what black holes really are, and they are rarely thought of ever exhisting. Since they emit no light no one has ever seen one, and in order to observe them you must look at gravitation of nearby matter. Black holes are amazing and intriguing, and although they are not the unproven phenomenon of worm holes they are still out of this world.