These two stars are a case of the myths fitting the reality, since Pollux is the brighter (17th brightest) while Castor languishes at 23rd. Since many versions of the Classical story of the Heavenly Twins made Castor the mortal one, it seems fitting that his star is slightly dimmer.
It is not hard to see the Twins in Gemini. The constellation looks in outline like two stick men, side by side. The two brightest stars are the two heads.
Castor is alpha Geminorum, and Pollux is beta Gem. Pollux is the 17th brightest star as seen from earth, while Castor is the 23rd, which may seem backforemost, but that’s the way it is. Pollux is a giant orange-hued star. Even cooler, Pollux has a planet orbiting it. Pollux is an older, cooler star, but Castor is made up of younger, hotter, dwarf white or blue stars. and may even be a sextuple star system.
The Graeco-Roman myth of Castor and Pollux (or Kastor and Polydeukes in the Greek version) said that they were the twin sons of Zeus, who appeared to their mother in the form of a swan. What Leda thought about this is not recorded, but at any rate she gave birth to the twin boys, as well as two girls, Helen and Clytemnestra. Inside eggs. (Moral: stay well away from gods in odd shapes.) At any rate, the two brothers, known as the Dioscouroi or “God’s Boys”, grew up together and were inseparable.
In some versions of this myth, however, only Polydeuces was Zeus’ son, a while Castor was the son of Leda’s husband. Hercules and his brother had a similar origin, but they famously did not get along.
One rather touching version of their story is that when the two died, Polydeuces, as a son of Zeus, was offered immortality, because of the twins’ helpfulness towards others. But Polydeuces refused unless he could share this gift with his brother. Zeus granted them an unusual boon: they would spend alternate days together in Olympus and Hades. To sweeten this deal, the sea-god Poseidon gave them the power to prevent shipwrecks, and to control horses. This fraternal love may be why so many artists have shown them arm in arm or with their arms around each other’s shoulders.
After Christianity came, the Twins took up a new existence, according to some, as the twin wonder-working saints Cosmas and Damien.
Later, however, Western Christianity would associate Gemini with either St. Thomas the Twin or St. James the Lesser.
Two other male pairs associated with the two stars are the Asvins, two sons of a chief god who were very similar to the Dioscouroi, right down to having a female to protect, Suryaa the sun’s daughter or Ushas the dawn-goddess. A less harmonious pair were the Romans Romulus and Remus, who quarrelled when Remus mocked the wall around Rome his brother was building, and his Romulus killed him.
In classical Hindu astrology, however, the two were a girl-boy pair, who represented the perfect marriage. Among the American Indians, the Maklaks of Oregon also saw a girl and boy in the constellation, and said that when they rose in December, they froze the lakes with their glance, but as they moved higher in spring, warmer weather was coming.
In Norse mythology either Þor or Oðin threw the giant Þiazi’s eyes up into the skies as stars, as part their atonement after his daughter demanded compensation for Þiazi’s murder. While no source states exactly which stars, the twins of Gemini would seem to be obvious contenders. (Some, however, hold out for another giant, Aurvandil, whose toe was thrown into the sky by Þor. Rigel is the toe, while the giant himself would be Gemini.)
In Caer Sidhe: The Celtic Night Sky Michael Bayley (149) suggests that the stars of Gemini are one of the Long Horned Oxen that two heroes were fighting over, or else the Two Rivals in the song Green Grow the Rushes, and Gawain and the Green Knight.
In astrology, Castor is a Mercury/Jupiter star, and gives success in publishing and law. Pollux is of Martial nature, and can make you brave, or malicious and cruel if ill-aspected.
As a final note, and a heads-up for next year, there is an asteroid shower every year known as the Geminids. These peak on the 13th – 14th December, so keep an eye out. It’s a relief from the pre-Christmas madness.
The image at the top comes from Wikipedia.