September 26, 2013
The human eye is unable to see black holes in space. But telescopes with special tools can help find black holes by seeing how they affect nearby stars.
In February, the Japanese space agency sent its Astro-H satellite into orbit around the Earth. The satellite’s job was to examine large structures in space, like huge black holes that exist at the center of most galaxies.
Galaxies are large groups of stars. Scientists estimate there are between 100 and 200 billion galaxies in the universe.
The Astro-H satellite fell apart after only a month in space. But in that short time, Astro-H was able to gather important information. It sent back data about the Perseus cluster – a grouping of galaxies in the star constellation Perseus. The Perseus cluster is home to hundreds of galaxies. They are 240 million light years from Earth.
What are black holes?
Black holes are areas where the pull of gravity is so strong that not even light can escape. Usually they happen after very big, supergiant stars explode. The exploded star turns into something called a “supernova.” It is very bright, but short-lived. Supernovas create the largest explosions in space.
The material remaining after the supernova explosion collapses. Gravity pulls, or crushes, all the matter into a very small space. When light can no longer escape that space, it is known as a black hole.
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