Cooling Earth..... hum.....
The earth would have cooled to an icy cinder many years ago were it not for
the decay of radioactive nuclei (principally uranium 238, thorium 232, and
potassium 40). Of course, the amounts of these heat-generating nuclei have
decayed over time, so their consequent heat output has also fallen. Unless
there is some other source of energy in the earth's core that is not
accounted for, the temperature MUST be lower than in the past.
Richard E. Barrans Jr., Ph.D. Assistant Director PG Research Foundation, Darien, Illinois