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
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Not 100% but I’m pretty sure fusion is colliding two hydrogens to create helium. So the neutrons would come from the two hydrogens.
it’s already there in the form of hydrogen isotopes.
Commercial fusion reactors often use a mix of deuterium and tritium.
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.”
if we are thinking about the *sun*, the answer is “complicated physics stuff happens”.
if you want more detail on fusion in stars, you should check out the somewhat-amusingly-named [pp chain](https://en.wikipedia.org/wiki/Proton%E2%80%93proton_chain). the answer to your question specifically involves the weak interaction. in the first step of the chain, for example, two protons fuse together. a neutrino and a positron are emitted. the weak interaction creates the neutrino, and it causes one of the *quarks* to change.
aside: protons and neutrons are made of quarks. protons comprise two up quarks and a down quark, while neutrons comprise two down quarks and an up quark. the weak interaction here causes an up quark to change to a down quark. this is the weird physics stuff, and I don’t have an explanation for how the quark itself changes beyond this.
the positron then carries away the extra positive charge that was lost from one of the protons changing to a neutron
in non-sun environments there are different ways fusion can happen, but this is how stars do it
Basically, for some really weird reason, if I remember correctly from my astronomy classes, the weak interaction turns one of the proton’s (up) quarks the other way creating a down quark creating a neutron,you could also use electrons as a neutron is basically just that, a proton + an electron,I remember our teacher telling us that P+E=N.How do the quarks change? TL:DR 2 protons collide, but the weak force is here to make our lives harder so it makes a neutrino and a positron (with the latter being the antimatter counterpart of the electron)they’re then carried off by hydrogen isotopes to make helium.
Idk coz my astronomy classes were long ago, like,10 years yo.
We do not know exactly how. But quarks have the ability to change flavor through weak interactions. So when two protons gets pushed together at high energies one of the up quark will change flavor to a down quark turning one of the protons to a neutron. This does create a positron and an electron neutrino.
Beta decay, specifically beta+ decay
Beta- decay has a neutron shooting out an electron and becoming a proton. This is a common form of decay and changes what element it is because the proton count changes
Beta+ decay happens in proton-proton fusion. In the unlikely event that they don’t just fall apart, one of the protons fires off a positron
Brain hurt beyond this point
Protons are made of 2 up quarks (+2/3 charge each) and 1 down quark (-1/3 charge). One of the up quarks spontaneously flips into being a down quark which changes it’s charge by -1 (+2/3 to -1/3) and it gets rid of that charge by firing off a positron and now that it’s 1 up (+2/3) and 2 down (-1/3 each) it’s a neutrally charged neutron
Why does this happen? It just kinda does unfortunately
For fusion reactions here on earth, it is already present in the hydrogen fuel. The most common, and easiest to achieve, fusion reaction is deuterium and tritium. Deuterium is hydrogen, but with a neutron along with the proton, and tritium is hydrogen, but with two neutrons in the nucleus. The fusion reaction is (1p 1n) + (1p 2n) = (2p 2n) + 1n. 2 protons and 3 neutrons in, 2 protons and 3 neutrons out.
Helium is created through nuclear fusion, which is the process of combining two atomic nuclei to form a heavier nucleus. During fusion, the protons and neutrons in the two nuclei come together to form a single, larger nucleus. The neutron is created when two protons combine, with one proton undergoing beta decay to become a neutron. Beta decay is a type of radioactive decay in which a nucleus emits an electron or positron, and a neutrino or antineutrino. The proton and the electron or positron that is emitted during beta decay combine to form a neutron, which becomes part of the helium nucleus that is created through nuclear fusion.
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