Transcript:

So, in the past couple of videos, we saw that in the Sun, the protons come arbitrarily close together, and a small fraction of them fuse to make helium. Remember, there are no actual collisions. These protons are quantum particles, so when they come close together, their wave functions overlap, and a tiny, tiny, tiny fraction of them fuse.

And this is important. It's a very small number, but it is nonzero. How small is the number?

One in every 10²⁸. That's insanely small, but it's still nonzero. It's important because a nonzero number multiplied by a big number leads to a big number, and there are lots and lots and lots and lots of protons. So a small fraction of them, 1 in 10²⁸, fuse to make a small reduction in mass. This is really important. It's a small reduction in mass, but when it is converted to energy using Einstein's E=mc², c² is a huge number, which is why there is a lot of energy that the Sun produces.

It is quantum and Einstein working together. It's brilliant.