Black Holes Come In Many Forms

In cosmology understanding black holes is a crucial area of study and ultimately may lead to resolving one of the biggest mysteries in physics, the combination of quantum mechanics and general relativity.

The simplest black holes are formed from collapsed stars. When a large star runs out of its fuel and fusion of smaller elements into heavier elements stops. At that point the outward pressure of the fusion process is too weak to resist the inward pull and pressure of gravity, so the star collapses inwards in massively violent explosive process called a supernova. If the star is large enough (3 or more times more massive than our Sun) then it may form a black hole.

Huge supermassive black holes are found at the centre of most large galaxies and it is still not clear how some of the largest of these formed. Principally how they managed to grow so large. It seems the universe is not old enough and therefore enough elapsed time for them to have grown to many billions of times as massive as our Sun.

Intermediate mass black holes are, so far, very few in number and this represents another mystery in cosmology.

Microscopic black holes are hypothetically possible and very many may have formed very early on in the life of the universe but none have been found so far.