Question: What is a black hole?

Edward Banks answered on 19 Mar 2020:

A black hole is an area of space that has become so dense and so massive that it collapses in on itself due to incredible gravity.
As a body in space (a planet, star etc) gets bigger, you need more and more energy to escape from the surface. For example- to escape from Earth’s surface you need massive rockets like the Saturn V; but to get off the Moon you only need a much smaller rocket like the lunar landing module!
As a star gets more and more massive, the energy you need to escape from it gets really really high- and this in turn means that the speed you need to be going to get off the surface gets ever faster. At a certain point, the speed needed to escape will become greater than the speed of light! Because nothing can go faster than the speed of light, this means nothing can escape; no even light itself! So the object becomes a black hole. Black because there is literally no light coming from it.