How do black holes form?
- Black holes form after a star reaches the end of its life.
- When stars are alive they are constantly turning hydrogen into helium in their core, which gives off energy to sustain the star.
- If the star is massive enough then it is able to fuse heavier elements until they reach iron.
- The reaction that creates iron does not give off any energy to sustain the star, and once that builds up the star loses its balance between gravity and radiation and collapses.
- The star collapses in a fraction of a second and explodes into a supernova which results in either a black hole or a neutron star.