Hercules was fighting a nine-headed serpent when another critter decided to join the fray. The crab was sent by the goddess Hera, who didn’t exactly get along with Hercules. The crab latched on to the strongman’s toe and wouldn’t let go. This fight didn’t last long, though — Hercules crushed the crab with his foot. But as a reward for its sacrifice, Hera placed the crab in the stars — as the constellation Cancer.

The crab is about a third of the way up the eastern sky at nightfall. But it isn’t much to look at — even its brightest stars probably are too faint to see from a light-polluted city. You can find its location, though. It’s about halfway between the bright star Regulus, which is low in the east at that hour, and the twins of Gemini, which are high above Regulus.

Like the constellation, the disease known as cancer was named for the crab. About 2400 years ago, Hippocrates, the father of modern medicine, was examining tumors in cancer patients. He called the tumors “karkinos” — the Greek word for “crab.” No one is sure just why; perhaps it was because the tumors were hard, like a crab shell.

A few centuries later, a Roman writer picked up the term, using the Latin word for crab: cancer. And later still, another doctor noted that the network of veins around a tumor resembled a crab’s legs. That solidified the name for this terrible disease — a name it shares with the faintest constellation of the zodiac.
 

Script by Damond Benningfield

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