Why is the centre of the Earth so hot?

This short video describes the reasons why the centre of the Earth is so hot.

[T-vd]

I appreciate him writing backwards for us

[keppela]

Two raisins? (sorry, couldn't resist : )

[JAUNEtheLOCKE]

Thanks! I was wondering why it was hot because I thought since it was very compacted then it should be kinda like- solid. And then since most people think of solids as at least colder than liquids then I thought the center of the Earth should be cooler 🤔

It all makes sense to me now, though!

[larryjones]

We need to figure out how to harness this energy, and without damaging our ozone layer.

[davewebster]

That really doesn't seem to explain how it stays hot for billions of years. That seems like a genuinely weak explanation. But hey, thanks for the science. I guess I just need to wrap my head around it.

[therecitizen]

Radioactive eh? 🤔,
We are still Alive by?
Guess we can drop spent rods into the nearest volcano and say "what goes around comes around"?

[MacDiggity]

Just say you don’t know and it is all still unproven theory