White and Black Dwarfs
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- In the last video we started with a star in its main sequence like the sun. And inside the core of that
- star you had hydrogen fusion going on. So that is hydrogen fusion and then outside of the core
- you just had hydrogen. You just had hydrogen plasma.
- And we say plasma, its the electrons and protons of the idividual atoms
- have been disassociated because the temaptures and pressures are so high.
- So they really just, kind of, its like this soup of electrons and protons
- as opposed to proper atoms that we associate with at lower temperatures.
- So this is a main sequence star right over here.
- And we saw in the last video that this hydrogen is fusing into helium.
- So we start having more and more helium here.
- And as we have more and more helium the core becomes more and more dense
- because helium is a more massive atom. It is able to pack more mass into a smaller volume.
- So this gets more and more dense until, at some point, while the core is becoming
- more and more dense, that actually makes the fusion happen faster and faster
- because its more dense, more gravitational pressure, more mass wanting to get to it,
- more pressure on the hydrogen that's fusing, it starts to fuse hotter.
- So hydrogen fuses faster.
- In fact we even see this in our sun. Our sun today is brighter and hotter.
- Its fusing faster then it was when it was born 4.5 or 4.6 billion years ago.
- But eventually its going to get the point where in the core you only have helium.
- So at some point the entire core is all helium.
- Its going to be way denser than this core over here.
- All of that mass over there has been turned into helium.
- Not all of it, a lot of it has been turned into energy, but most of it is now in helium.
- Its going to be a much much smaller volume. The whole time the temperature