SECTION III - IS THE MOON AN ANCIENT COMET?

Summary

Hypothesis of Maupertuis : the planetary satellites originally comets, which have been retained by the attractions of the planets–The Arcadians and the moon–Refutation of this hypothesis by Dionys du Séjour.

In the same spirit of speculative enquiry, it has likewise been asked if the moon is not an ancient comet which the earth has diverted from its orbit about the sun, and forced to gravitate about itself. ‘ Not only, ’ says Maupertuis, ‘might a comet carry away our moon, but it might itself become our satellite, and be condemned to perform its revolutions about our earth and illuminate our nights. Our moon might have been originally a small comet which, in consequence of having too nearly approached the earth, has been made captive by it. Jupiter and Saturn, bodies much larger than the earth, and whose power extends to a greater distance, and over larger comets, would be more liable than the earth to make such acquisitions ; consequently Jupiter has four moons revolving about him, and Saturn five. ’

Upon what foundation, upon what serious reasoning has Maupertuis erected this ingenious hypothesis? He does not tell us. Pingré, who records it, observes that the partisans of this opinion based it upon an ancient tradition mentioned by Ovid and Lucian.