When the Earth Had Two Moons - Issue 13: Symmetry
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For more than half a century, the moon had been mocking the best minds in science, and for Erik Asphaug enough was enough. The taunting began three years before Asphaug was born. On Oct. 7, 1959, the Soviet Luna 3 spacecraft looped behind the moon, snapping off a series of grainy but distinct photos and then radioing them home. Because the moon’s rotation is perfectly synchronized with its rotation, one hemisphere always points toward Earth while the other always points away, unseen. Luna 3’s first-ever images of the lunar far side revealed an expanse of rugged, blandly gray highlands—a vista utterly unlike the near side’s charismatic, Man-in-the-Moon markings. It didn’t take a planetary scientist to recognize the weirdness of that split personality. “I remember as a boy seeing one of the (...)