The suns energy is from fusion, fine makes sense.
But the core is a hot spinning liquid metal generating tremendous amounts of heat. Why hasn’t it cooled down? How is it replenishing its energy?
In: Planetary Science
Most of the interior heat is latent heat from the formation of the planet, compressing a planets worth of mass generates a lot of heat. The rest is actually generated by the decay of radioactive elements. It’s just hard to shed heat when your only option is to radiate it into space, and there is a relative cold layer on top trapping the heat below
When the earth first formed, it was liquid rock and metal. It was very very hot. Over time the surface cooled and became solid but was still very hot. The surface cools and heat from the center moves to the surface where it is colder. Because rock is a great insulator of heat, this takes a long, long time.
Radioactive material that was denser then rock sank into the core, and that material releases heat as it decays to other materials. Keeping the core hotter then if it didn’t have said material.
It took millions of years for the surface to cool from liquid rock to solid rock. And it took millions more for it to cool enough for h2o gas to turn to liquid water. The cooling is a long and slow process, heat from the sun heats the surface and slows down the cooling as well.
The solid crust of the earth has been getting slowly thicker over billions of years as the earth slowly cools and has it gets thinker slows down heat loss even more as a insulator.
Eventually the core will cool and solidify but that still billions of years away.
>But the core is a hot spinning liquid metal generating tremendous amounts of heat. Why hasn’t it cooled down? How is it replenishing its energy?
The energy mainly come from the movement, but you are right, it is cooling down, and movement is reducing. Other than radioactive decay it’s not replenishing it’s energy, and even that probably doesn’t contribute much.
So in the past it was really hot with lots of movement, and it is cooling down just quite slowly.
It’s mostly energy left over from it’s formation. Some comes from radioactive decay of uranium etc.
When you get a mass this size being crushed into a sphere by it’s own gravity, especially in an early solar system that’s already quite hot, you end up with an incandescent ball of magma. Luckily, the surface cooled enough over time to become solid.
Latest Answers