Geothermal Heat Generation, the third option

I once read that geothermal heat generators...
Geothermal heat generators are basically giant pipes of water that go deep underground to the hotter parts of the crust, heat the water to boiling, then the water naturally rises and a circular flow pattern emerges...the water rises and cools, then sinks and heats...as this circular flow pattern occurs, geothermal generators are essentially fan blades in the flow of water that spin and turn a shaft which turns a brush which creates electrical power. It is estimated that all the world's power needs could be supplied by geothermal heat generation.
I once read that geothermal heat generators could provide all the power the world ever needed.
This is good, because geothermal energy has zero emissions, zero toxic waste, zero mining of coal, zero anything...just free energy.

But as my friend Noah Ball will tell you, the first law of thermodynamics is that energy can neither be created, nor destroyed. So if you are pumping heat out of the Earth's core...well fast forward 5,000 years and suddenly you have a very cold core of the Earth. I am exaggerating, of course, because it would take much longer than that the exhaust the heat of the Earth.

But you wouldn't have to exhaust it, just cool it. A tiny decrease in Earth's core temperature would lead to drastic changes:
- Cooler molten iron would condense, increasing the size of the solid core of the Earth
- A large core would spin slower, decreasing Earth's magnetic field and slowing the rotational speed of the Earth (and increasing gravity?)
- A decreased magnetic field would make the surface more susceptible to bombardment by the Sun's radiation.
- A slower rotation of the Earth would screw up the tides, the number of hours in the day, and basically anything that relied on the "28 day" cycle of the Earth would have a problem (girls I'm looking at you)

Then again, a cooler core might do the opposite, as the solid iron core of the Earth is solid because of a P-T curve, and so a decrease in temperature might instead decrease the size of the core:
- The decreased core would spin faster, increasing the rotational speed of the Earth and decreasing the day length.
- The stronger magnetic field caused by the faster spinning core might block too much of the sun's energy, harming plant life that depends on it.
- See above about tides, hours in the day, and 28 day cycles

In either case, a cooling core is bad news. And not to scare you...but the Earth is slowing down. And the moon is gradually moving away from Earth.


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