Originally posted by Paul Dirac II
No, other than the rule of thumb that large things change slowly. But of course that argument works both for a very gradual slowing of the moon's rotation and a very gradual cooling of Earth.
For whatever reason, my intuition suggests millions of years for the former and mere decades for the latter. But my intuition shouldn't carry weight with anybody. 🙂
You think the Earth's crust cooled and solidified in decades???
Try tens of millions of years at least.
The vacuum of space is a really good insulator.
After 4.5 BILLION years only the top few tens of miles has solidified.
Everything else is still molten.
If you assume an average thickness of 50km, then you get an average rate
of solidification of 0.01 mm per year.
Now it obviously hasn't been solidifying at a constant rate, as the crust cooled the
rate of heat loss and thus further solidifying would have reduced as well.
But it does rather suggest that solidifying the surface should have taken orders of
magnitude more than mere decades.