On Mon, 28 Jan 2008 12:12:02 +0000, Mike Scott wrote:

The Natural Philosopher wrote:
...
In fact, there is a puzzle, in that the earths actual temperature is
more than can be accounted for by the solar radioation and its initial
temperature post formation, leading to a lot of speculation that it is
in fact a large fission reactor in its own right.

Isn't there a large molten iron core that makes up the difference? Been
there since year dot, or thereabouts, cooling all the time.

If you do the calculations assuming that no energy is being added into
the core then the Earth would cool down in about 10-30 million years.

The fact that it seems to have been staying rather hot is down to some
extra energy begin generated in the core.

I have not done the calculations or found the links but the debate seems
to be between whether the energy is derived from radioactive of heavy
elements or whether there are (relatively) high density pockets of
fissile elements allowing for some naturally occurring reactors.






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