A black hole is caused by an intense amount of gravity. Usually this occurs when the gravity of a star is so strong that it causes the star to collapse on itself. Once this happens, the gravitational force is so strong that light is even trapped inside. so when a star dies a black hole forms.
http://answers.ask.com/Science/Physics/what_causes_a_black_hole
Even though a black hole is invisible it can be observed through its interaction with other matter.
ReplyDeletehttp://en.wikipedia.org/wiki/Black_hole
A black hole is formed when a star burns out. It gets its name from the fact that the star collapses into itself, becoming so dense that its gravitational pull keeps even light from escaping.
ReplyDeleteBlack holes are the evolutionary endpoints of stars at least 10 to 15 times as massive as the Sun. If a star that massive or larger undergoes a supernova explosion, it may leave behind a fairly massive burned out stellar remnant. With no outward forces to oppose gravitational forces, the remnant will collapse in on itself. The star eventually collapses to the point of zero volume and infinite density, creating what is known as a " singularity ". Around the singularity is a region where the force of gravity is so strong that not even light can escape. Thus, no information can reach us from this region. It is therefore called a black hole, and its surface is called the " event horizon ".
ReplyDelete