The Crab

By 7:30, Regulus, the first bright star of spring, rises, and with it, the constellation of Leo. But these are not the first stars of spring. Those rise earlier. The first constellation of spring is Cancer the crab.

There are two ways to find Cancer. Without waiting for Leo, just follow a line through the Gemini twins, Castor and Pollux. Continue that line twice the distance from Castor to Pollux. That small constellation of dim stars with a blurry spot at the center is Cancer. Or, if you wait for Leo, then look halfway between the Gemini twins and Regulus.

Through binoculars, that blurry spot resolves into a cluster of hundreds of stars, like a swarm of bees. Born together hundreds of millions of years ago, they now slowly circle each other as they move as a group through space.

What is a constellation as slow, as ungainly as a crab, doing in the sky, the home of fleet-footed heroes, winged birds, and monsters of great power? Our best source for an explanation of why certain constellations are in the sky are the Greek myths.

It seems that Zeus, that celestial philanderer, was so besotted by the mortal Alcemene that he came to Earth and, with her, fathered the infant Hercules. His wife Hera, outraged by his adultery but powerless to vent her rage on him, swore vengerance on the child. When Hercules became a man, and was fighting the many-headed Hydra, she sent a crab to distract him by biting him on his foot. Alas for the crab! Hercules simply stepped on him, but for this failed attempt, Hera placed the crab in the sky.

(01/12/05)