eli5 How did the sun start emitting heat?

Question

Follow up on the recent post *”how can the sun just continuously burn and burn?*”

Can someone explain how the sun actually started its nuclear fission?
Oppenheimer did not go a dropped a nuke on it 😉

In: 1

Answer 1

There is so much matter on the sun that the force of gravity causes fusion of hydrogen into helium. If this fails to start, it never becomes a star, but rather becomes what’s known as a brown dwarf.

This is an absolutely immense amount of matter. The absolute minimum is about 75x the mass of Jupiter.