J. Laskar, F. Joutel & P. Robutel
Astronomie et Systemes Dynamiques, Bureau des Longitudes, 77 Avenue Denfert-Rochereau, F75014 Paris, France
ACCORDING to Milankovitch theory [1,2], the ice ages are related to variations of insolation in northern latitudes resulting from changes in the Earth's orbital and orientation parameters (precession, eccentricity and obliquity).
Here we investigate the stability of the Earth's orientation for all possible values of the initial obliquity, by integrating the equations of precession of the Earth. We find a large chaotic zone which extends from 60 deg to 90 deg in obliquity.
In its present state, the Earth avoids this chaotic zone and its obliquity is essentially stable, exhibiting only small variations of +/- 1.3 deg around the mean value of 23.3 deg.
But if the Moon were not present, the torque exerted on the Earth would be smaller, and the chaotic zone would then extend from nearly 0 deg up to about 85 deg.
Thus, had the planet not acquired the Moon, large variations in obliquity resulting from its chaotic behaviour might have driven dramatic changes in climate.
In this sense one might consider the Moon to act as a potential climate regulator for the Earth.
http://www.nature.com/nature/journal/v361/n6413/abs/361615a0.html
It’s just uniformitarian gobbledygook. Nice ‘climate change’ angle in there too.
It’s always amusing to see, coming as I do from a long familiarity with uniformitarian objections to Velikovsky, that everything in their little outlook results just-so in stability, because any change at all in what is seen would have led inevitably to chaos.
I like their use of the phrase “acquired the Moon” — the Moon is clearly not the result of a large impact on the proto-Earth, but a later ‘foundling’, captured after a series of encounters made over some millions of years.