1. The force of gravity of a black hole is so great that it can distort the space around itself.
2. Leaving a black hole can do nothing at all. It attracts even photons of light.
3. It is quite possible to see it visually. It looks like a black sphere surrounded by a glowing halo – an accretion disk.
4. They may well have their own planetary systems.
5. The origin of life on a planet revolving around a black hole is considered impossible. Its monstrous gravity will attract all comets and meteorites to itself, and nothing, no organic matter, will fall on the surface of the planet from the outside, so it will remain sterile.