Question

what is the black hole?

Answer 1

A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light—can escape from inside it.

Answer 2

black holes are places of mystery. The laws of physics predict their existence but cannot explain what happens inside a black hole. Once we can do that, we will have stepped beyond the work of Albert Einstein and taken the next big leap in our understanding of the Universe.

Put simply, black holes are places where gravity is so strong that nothing can escape once it gets too close. This sets them apart from all other celestial objects, where you would always – in principle – be able to build a rocket strong enough to escape into space.