From: Zack Clayton [mailto:zack.clayton@EPA.STATE.OH.US]
> Phil,
>
> Yes life on Earth probably does depend on a hot core, and
> current theory is that the energy is supplied by
radioactive DECAY.
>
> The molten core allows the dynamo mechanism to create the
> Earth's magnetic field that Shields us biologically
from a
> lot of particle bombardment from the solar
wind, and Shields
> the atmosphere from solar
wind erosion. A molten core allows
> plate tectonic
subduction and extrusion that recycles carbon
> and
oxygen so everything doesn't lock up in sediments.
>
> Pressure by itself doesn't create heat,
contraction under
> pressure creates heat. The
Earth gets warmer as you go
> deeper under the
surface due to the insulating properties of
>
thickness. Without the decay heat the Earth would have
> frozen up long ago like Mars, with loss of magnetic shielding
> and a permanent case of rust.
Hormesis? Too much or too little = dead! :-)
Regards, Jim