Around October 23 each year, the Sun crosses into the eighth sign of the Western zodiac, and horoscope columns turn to Scorpio. The sign borrows its name from a constellation that, unusually, looks like its namesake: a curve of bright stars hooking down through the Milky Way, a red star at the center of the body, and a tail raised to strike.
That resemblance may help explain why the figure has lasted so long. Popular guides routinely call Scorpius one of the oldest constellations known. The claim holds up better than most sky lore, though the number usually attached to it deserves a second look.
A burning sting in Babylon
The constellation historian Ian Ridpath writes that the Sumerians knew the figure as GIR-TAB, the scorpion, "over 5,000 years ago." The Constellation Guide repeats the same figure. It is a round number of the kind that travels further than its evidence. The written record that can actually be dated comes later. Babylonian star catalogues naming the scorpion date from at least 1100 BCE, and the compendium known as MUL.APIN, which lists 66 stars and constellations with their rising and setting dates, was most likely compiled around 1000 BCE. Its earliest surviving copy was made in 686 BCE.
In those texts the constellation is MUL.GIR.TAB, signs that can be read literally as the creature with a burning sting. Its brightest star was GABA GIR.TAB, the breast of the scorpion, counted in MUL.APIN among the stars of the god Ea in the southern sky.
So the scorpion is old by any fair measure: about three thousand years in writing, and possibly far older in speech. A 2022 review of the zodiac in the history journal Sobek sums up the line of descent. Babylon supplied the twelve signs, and the Greeks, then the Romans, borrowed not only the names but the shapes of the figures.
The scorpion and the hunter
The Greeks inherited the figure and gave it a story, or rather several. A fragment attributed to Hesiod, preserved in the Catasterismi credited to Eratosthenes, says Orion went hunting on Crete with Artemis and Leto and threatened to kill every beast on earth. The Earth, angered, sent up a scorpion of very great size, which stung him to death. At the prayer of the two goddesses, Zeus set Orion among the stars, and the scorpion too, as a memorial.
The poet Aratus, writing in the third century BCE, moved the scene to the island of Chios and changed the offense. In his version Orion laid hands on Artemis's robe, and she raised the scorpion against him. The Roman mythographer Hyginus kept the boast and has Jove set the scorpion in the sky "as a lesson to men not to be too self-confident." Ovid, in his Fasti, gives Orion a nobler end: the scorpion lunges at the goddess, Orion blocks it, and Leto lifts him to the stars as a reward.
The versions share one detail a person can check. Orion and the Scorpion sit on opposite sides of the sky, so one sets as the other rises. Aratus put it plainly: "at the rising of the Scorpion in the East Orion flees." Ridpath suggests the myth may have grown out of that observation rather than the other way round.
Claws that became the Scales
The Greek scorpion was larger than the modern one. It came in two halves: Skorpios, the body and sting, and Chelae, the claws. Ovid, in the Metamorphoses, describes a scorpion that "sprawls across two signs of the zodiac." Hyginus explains that the claws spread so wide that one part came to be called the Balance. The Romans made the split formal in the first century BCE, and the claws became Libra. The Babylonians had also called those stars the Claws of the Scorpion.
Traces of the old arrangement survive in the catalogues. The star Bayer labeled Gamma Scorpii lay at the end of the southern claw. It was later moved to Libra as Sigma Librae, a letter assigned by Gould in his Uranometria Argentina of 1877, so there is no longer any Gamma Scorpii at all. Even the name has split. Astronomers call the constellation Scorpius; Scorpio is the old name, now used by astrologers.
The red heart
The star at the center of the body is Antares, and its name is usually translated as rival of Mars, for its reddish orange color. Ridpath points out that the star name scholar Paul Kunitzsch noted the Greek anti can also mean like, so the name may simply mean like Mars. Sources disagree about where the comparison began. The Constellation Guide says it possibly goes back to Mesopotamian astronomers; other summaries call that outdated speculation, since the Mesopotamian names refer to the scorpion's body, not the planet.
Ptolemy, in the Almagest, described it as "the middle one of the three bright stars in the body," and it was one of the few stars he named. Oddly, he ranked it second magnitude, perhaps because he saw it close to the horizon. Elsewhere it carried other meanings. In Egypt it represented the scorpion goddess Serket; in Persia it was one of four royal stars; in ancient China it was Huo, the fire star, at the heart of the Blue Dragon.
Modern astronomy has made it stranger, not tamer. The astronomer Jim Kaler describes a red supergiant roughly 550 light years away, cool at about 3,600 kelvin yet so large that its disk can be measured directly, with a radius of about 3.4 astronomical units. It is massive enough to end as a supernova, at some unknown point in the future.
One hook, many skies
Other cultures saw the same stars and drew something else. In China, the hook of the tail was Wei, the tail of the Blue Dragon. A single star near its tip, Fuyue, stood for a legendary slave or hermit who became chancellor to the emperor Wu Ding around 1200 BCE. In Java the figure became a leaning coconut tree, and Bugis sailors split it into skate stars and shark stars for navigation.
In Hawaii it is Ka Makau Nui o Māui, the big fishhook of the demigod Māui. The Polynesian Voyaging Society's star guide describes it set in a dark patch of the Milky Way called the Fish, so that as the hook rises in the southeast it appears to drag the great fish across the sky. Antares is Lehuakona, the southern lehua blossom. The same guide notes that the hook lies 180 degrees from Orion, the opposition the Greeks turned into a death.
Where the Sun actually is
The astrological sign and the constellation are no longer the same thing. Under the tropical zodiac used in most Western astrology, Scorpio is a fixed slice of the ecliptic, 210 to 240 degrees, which the Sun crosses on average from October 23 to November 21. The constellation runs by different rules. Inside its official boundaries the Sun spends just six days, from November 23 to November 28, and much of the gap is due to the neighboring constellation Ophiuchus. Old star maps even draw that figure's leg and foot across the scorpion's body.
Then, around December 2, the Sun passes about 5 degrees north of Antares, the red star Babylonian observers called the breast of the scorpion. No horoscope marks that date.