how do scientists know that nuclear fusion is going on in the sun?

Question

Im guessing no one has gotten close enough to the sun to check. So how do they know for sure?

In: Physics

Answer 1

We don’t know anything for sure. We can only make models based on what we’ve previously observed and make predictions from that model. If the predictions we make are accurate then that gives us evidence that the model is correct. If we observe something that contradicts the model then we know that the model is not accurate or there is another unseen factor at play. We are pretty sure that fusion is going on inside stars because most young stars we see are mostly made of hydrogen based on the kind frequencies light they give off. Older stars are compromised of more heavy elements based on the frequency of their light.