EXPRECT FROM NASA

     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 ara invisible . Space telescopes with special tools can help find black holes . The special tools can see how stars that are very close to black holes act differently than other stars.