A Mystery of Space: S T A R S- [What is a Black Hole?] U12

When a massive star dies, it may turn into a neutron star. But, if the force of gravity around the neutron star is strong enough, a black hole could be the result. Black holes occur when gravity is so strong that space acts like a one-way funnel. Anything from light rays to huge planets can get sucked into this funnel. Anything that is sucked into a black hole is compressed into nothing, and disappears from our universe. A black hole is the end of space and time.

A spiral-shaped disk of dust is being sucked in by a massive black hole in the galaxy NGC 4261

Pretend that an asteroid is being pulled into a black hole. As it nears the black hole, it would seem as if it were moving slower, but would actually be speeding up very rapidly. Soon, it would reach the "lip" of the black hole. This "lip" is called the horizon, and is the point of no return. Once the asteroid reaches this point, it will never come out. Then, as the asteroid enters the black hole, it would be shrinking in size until it finally collapses into a singularity, or an object without dimension, but with infinite density.