**Ask a monkey a physics question thread**

[OngBonga]

Q: and what is the source of energy for the Earth's inner core?

Um, don't we know that already? I thought there was a shit load of radioactive decay going on down there?

And tidal heating. The interior does indeed have a tide, and when it moves it experiences friction.

Plus the friction caused by the convection currents.

Plus we're floating in a vacuum, so the planet is well insulated.

It's no surprise to me that the planet isn't cooling down in any hurry.

[MadMojoMonkey]

Um, don't we know that already? I thought there was a shit load of radioactive decay going on down there?

No, we don't know. Whatever it is, it's been down there for 3.5 billion years, so it'll need a quite long half-life to not have already decayed. Which implies that there must be a heck of a lot of it to keep it going.

Sources cite the solid inner core as being composed of iron-nickel composites. Not radioactive.

And tidal heating. The interior does indeed have a tide, and when it moves it experiences friction.

Sounds plausible that it contributes. How much energy is added to the Earth's core by tidal heating over time?

Plus the friction caused by the convection currents.

Which dissipates energy from the system, 'cause 2nd law of thermo says entropy never decreases and friction is not a conservative force, so therefore cannot yield a 0 entropy change.

Plus we're floating in a vacuum, so the planet is well insulated.

The law of blackbody radiation says that everything radiates energy in the form of photons, merely due to the fact that it is not at a temperature of absolute 0.

It's no surprise to me that the planet isn't cooling down in any hurry.

Don't be convinced by clever sounding words which describe plausible answers without talking actual numbers and time frames.

[OngBonga]

Don't be convinced by clever sounding words which describe plausible answers without talking actual numbers and time frames.

Can't I leave all that to you while I sit here and wildly speculate?

[MadMojoMonkey]

Can't I leave all that to you while I sit here and wildly speculate?

I'm impressed at how you're digging into this one.

I haven't looked at this in over 5 years, and I don't remember all the details, just the conclusion that the Earth's inner workings are poorly understood and we don't yet have a (complete) working model of the Earth's magnetic field.

[OngBonga]

I'm impressed at how you're digging into this one.

I actually provided links to show I'm researching! It's interesting stuff, I like thinking about this kind of shit. This is easily my favoutire thread here.