“However dangerous . . . the shock of a comet, it might . . . only do damage at the part of the Earth where it actually struck. . . . Perhaps we should be very surprised to find that the debris of these masses that we despised were formed of gold and diamonds; but who would be the most astonished, we, or the comet-dwellers, who would be cast on our Earth? What strange beings each would find the other!”

—Maupertuis, Lettre sur la com’te, 1752. Quoted by Carl Sagan in Broca’s Brain, 1979.