eli5 where does the neutron come from when creating helium in fusion?

Question

I keep seeing things about how protons turn into neutrons but that makes no sense to me. How can the quarks of a proton seemingly change and turn into a neutron? I have a project and I need to know this for both neutron stars and nuclear fusion

In: 3

Answer 1

You can turn neutrons into protons, or protons into neutrons, with the help of electrons.

“Beta decay” is an example where a neutron turns into a proton and an electron, and the resulting free electron is emitted as a beta particle.

You can do the reverse, and mush an electron into a proton, and make a neutron. But it’s a lot harder. It’s how neutron stars are formed. For the purpose of your project, look up “electron degeneracy pressure.”