In the comic movie "A Funny Thing Happened on the Way to the Forum," the character Senex, lamenting the state of his marriage, says "Never fall in love during a total eclipse." This joke is rooted in reality, because for centuries the ancient peoples of Earth regarded solar eclipses with awe and fear. The Sun gave warmth and life to the Earth, and for it to be blotted out at midday was surely an indication that the gods were displeased with humans, or at least was an omen of some impending disaster. Although the term eclipse applies to any passage of one large celestial object in front of another (two stars orbiting one another, for example, may eclipse each other if their orbital plane is tilted at the proper angle as seen from Earth), the best-known manifestations of eclipses are those involving the Earth and the Moon.

Solar...