Question

What are some interesting facts about black hole?

Answer 1

You can’t directly see a black hole.
Black holes come in a range of sizes.
A Massive Star Collapsing In Upon Itself

Answer 2

it is also believed that galaxies collide with each other due to gravitational force of the black holes.
no one has yet discovered a black hole for certain. but astronomers have found compact objects that are almost certainly black holes.
in the strictest and most exact sense, there are currently 14 known black holes.