What is this?
A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying. Because no light can get out, people can't see black holes. They are invisible.
The supermassive black hole at the center of the Milky Way galaxy is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths. Scientists think the smallest black holes formed when the universe began.
More Info:
wikipedia.en.com
What are your thoughts on this subject?
45 Comments
Gerald Woerner
I have trouble with black holes being formed when the universe began. If they are formed from dying stars and stars take millions of years to go through their lifetime, how is it possible?
steve
A good question, Felicity. The matter that falls into the black hole gives up tremendous amounts of energy, which surrounds the black hole in what is termed an accretion disc. This can be "seen" by using different detection methods (e.g., X-ray sensors, Gamma ray sensors, etc.). The best example of this is Cygnus X-1, an X-ray source in the constellation Cygnus. It is generally thought to be, but has not been proven to be, a black hole.
Felicity Spencer
If black holes are invisible, how do you know they are there?