Define black hole

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.

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. Black holes are generally defined as "a place in space where gravity pulls so much that even light cannot get out. A black hole is where gravity has become so strong that nothing around it can escape, not even light. The mass of a black hole is so compact, or dense, that the force of gravity is too strong for even light to escape.