GEMINI The Twins

The association of the two brightest stars of Gemini with an earthly pair has been almost universal. In Egypt they were a pair of sprouting plants, and they have been identified in Phoenician culture as a pair of kid goats. The Mesopotamian prototype for the classical twins shows them as a pair of naked boys. In one Roman interpretation they were Romulus and Remus, the legendary founders of Rome.

In Greek myth, the twins are Castor and Polydeuces (Pollux to the Romans), the Dioscuri ("sons of god"). They were born from an egg laid by Leda, queen of Sparta, after she had coupled with Zeus (Jupiter) disguised as a swan. Mortal Castor was the son of Leda's husband; immortal Polydeuces was the son of Zeus.

The twins traveled to the land ruled by Idas and Lynceus. Idas killed Castor with a spear, whereupon Polydeuces, although injured, killed Lynceus, Zeus intervened and struck Idas dead. Polydeuces refused to accept his immortality unless Castor could share it. Zeus allowed the two to alternate their days forever between the realm of the gods and the underworld, Hades.

Poseidon (Neptune) made the twins the protectors of sailors; they were both members of the crew (the Argonauts) that Jason enlisted to help him retrieve the Golden Fleece. Accordingly, the stars Castor and Pollux stand high above the mast of Argo Navis.

A winter constellation, Auriga lies immediately to the north of the horns of Taurus, with which it shares the star Elnath. Once recognized, the distinctive curve of stars in Auriga is never forgotten: the curve runs clockwise from Elnath through ) " ¸ to (Menkalinan, magnitude 2, "charioteer's left shoulder") to brilliant Capella (magnitude 0, sixth brightest star in the sky, 46 light years distant, "she-goat"). At the far end of the curve is a little cluster of stars denoting the kids. Auriga also has three star clusters, M36, M37, and M38, worth viewing with binoculars.

The brightest stars in Gemini, Castor and Pollux (magnitudes 1½ and 1, respectively), are 4½º apart. The constellation resembles a rectangle lying slant-wise across the ecliptic. The third brightest star, Alhena (magnitude 2), is at the far end of the constellation. Castor is actually a compound system of 6 stars, 3 pairs of binary systems (any system beyond 6 stars is thought to become unstable).