Planetary Core

>>7965211
>Is there a nuclear chain reaction always happening in the Earth's core?
No

>Or is it just hot because of all the friction and pressure from gravity?
Yes

>Why was the planet so much more volcanic in the past / why is it cooling off with time?
Energy goes from hot to cold, high to low energy states.

>Will it eventually reach a state of having no more volcanism or plate tectonics? Could the core ever become "cold?"

Tidal forces from the moon add energy to the core, helping to keep it molten. Eventually, it will cool off though.

It's hot for two reasons:
1) It started out hot and hasn't cooled down yet.
2) There is a lot of radioactive material in the core.

Both slowly decrease with time.

About half of the heat coming from the earth's core is the product of the fission of heavy elements as they split into lighter ones. The rest of it comes from friction and pressure.
Not sure how much this ratio has changed since the earth was formed

why don't we get our energy from there then?

supplemental question: is Yellowstone going to explode?

>>7965255
No expert, but I might as well comment so someone(who would NEVER have posted otherwise- you know who you are, faggot) will take the opportunity to correct me and perhaps give you a better answer.

Well, first off, we do; It's called geothermal energy, but only a small amount is harvested. Why don't we perhaps dig straight into a magma well and harvest heat from there? Well, like I said, I'm no geologist or anything, but removing all that heat could have adverse affects on our environment, like on Mars, its core is "dead", could something like that happen to our planet from harvesting too much heat and cooling our planet down? Probably not in the near future, but it's a thought.

>>7965261
you think mankind cares about adverse effects to the environment? There's just no efficient way of "harvesting" heat. Digging the hole would take more energy then we could ever produce.

>>7965255
>why don't we get our energy from there then?

The logistics of breaking through the crust into the mantle and avoiding a massive volcanic event are not that simple. Suffice to say humanity likely does not have the technical know-how to do so. Even then, why would we want to, the Sun's energy is more abundant and easily harvested.

>supplemental question: is Yellowstone going to explode?

Maybe. There are major volcanic events every few hundred million years. There is just no way of knowing other than monitoring the land around the caldera. Even then it would just be probabilistic.

File: dygram.png (8KB, 428x243px) Image search: [Google]

8KB, 428x243px

>everyone knows Earth's core is magnetic
>nobody thinks it's commutates every time the sun flips polarity

If you ask me, the core won't ever cool off as long as we have a sun

>>7965251
there ought to be a formula for calculating the rate of heat loss in a planetary body. There are so many factors though. I imagine having higher planetary mass/denser composition and more greenhouse gases helps to retain more heat for a longer time. Tidal forces brought about by moons and planetary rings also increase geothermal energy.

I don't know why some people think gas giants have icy cores. I would think even a rogue-planet gas giant drifting about cold interstellar/intergalactic space would be massive enough to have tremendous amounts of nuclear/geothermal energy coming from its core, while still having enough of a greenhouse effect to retain all that heat and make the planet not freeze up (even with no star to warm it)