Origin of the Moon

Abstract

If you look at a globe of the Earth, the largest feature is the Pacific Ocean. A century ago, George Darwin (son of the evolutionist) proposed that the Moon had formed by a splitting or fissioning of our own planet. He calculated the Moon’s orbital motion, and traced it back to an early time when, he believed, the Moon was only 6000 miles from the Earth’s surface and the Earth was spinning rapidly, its day only 5 hours long. Darwin suggested that unstable oscillations in our rapidly spinning planet might have served to break the Moon away. Soon, someone else suggested that the immense Pacific Ocean basin represented the cavity from which the Moon came. Whatever the merit of Darwin’s idea—we still think that the Moon was once much closer to the Earth, but actual spontaneous fission is no longer accepted—one lesson can be learned: Creation of the Moon from the Earth is a process of truly enormous scale. The Moon, after all, is a quarter the diameter of the Earth, although it has only 1/80th of the Earth’s mass.