Black Holes

A black hole is a great amount of matter that is packed into a small space. It is so dense that its gravitational field is so strong that nothing, not even light, can escape it. Many black holes result from the death of a star. Supermassive black holes exist at the center of most galaxies, including our milky way galaxy.

History
The existence of black holes was first predicted by Albert Einstein in 1916 with his theory of general relativity. The term “black hole” was coined by John Wheler in 1967. The first black hole discovered was detected in 1971.

Observing black holes
[[File:SWIFT_2.jpg|thumb|left| This image shows intense X-ray flares thought to be caused by a black hole devouring a star.

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Since black holes absorb all light, scientists can’t directly observe them with telescopes that use forms of electromagnetic radiation. They can, however, be observed indirectly, by studying their effect on nearby objects. For example, as a black hole consumes a star, it can tear it apart as it is pulled toward the hole. The attracted matter can heat up and emit x-rays that can be observed.

Formation
When large stars die out, they lose energy for fusion and collapse in on themselves. It blows out material in a supernova explosion. A black hole forms when the core collapses into a gravitational singularity, a single point that contains all the mass of the original star.

After the creation of a black hole, the amplified magnetic field and heat of the collapsed star produce beams of radiation perpendicular to the spinning plane of diffuse material. The beams force vast amounts of particles and energy away from the black hole close to the speed of light*. This is a “gamma ray burst” where gamma rays are emitted, which is the brightest electromagnetic event that occurs in the universe. This typically only lasts for a few seconds.