Gemini Constellation

 Facts About the Twins

In astronomy, Gemini is a constellation in the northern sky and one of the constellations in the zodiac, which is the area of the sky that includes the apparent paths of the sun, moon and planets. The Gemini constellation has been described by cultures since ancient times and remains one of the 88 modern constellations defined by the International Astronomical Union (IAU). 

Gemini is Latin for "twins," although the twins identified with the constellation depend on the culture, according to Encyclopedia Britannica. In Egyptian astrology, the constellation was identified with twin goats, while Arabian astrology said it was twin peacocks. The Western world tends to identify these twins as Castor and Pollux from Greek myth. But other twin pairs identified with Gemini in the Western world include the older and younger Horus and the mythical founders of Rome, Romulus and Remus.

Gemini Constellation Credit: Stellarium

Locating Gemini

Gemini is fairly easy to spot in the sky, even for amateur stargazers. It is located northeast of the constellation Orion and between the Taurus and Cancer constellations. Best viewing is during February. By April and May, the constellation can be seen soon after sunset in the west.

• Right ascension: 7 hours
• Declination: 20 degrees
• Visible between latitudes 90 degrees and minus 60 degrees

Notable Stars and Objects

The two brightest stars in the constellation, also named after Greek mythology's Castor and Pollux, represent the heads of the twins, while fainter stars outline the pair's bodies. Pollux, a red giant star, is 33 light-years from Earth, according to NASA, while Castor is about 51 light-years away from us. (A light-year is the distance that light travels in a year, which is about 6 trillion miles, or 9.6 trillion kilometers.) Pollux has at least one massive planet orbiting it, while Castor has two companion stars.

Other notable objects in the constellation include the Eskimo Nebula, Medusa Nebula and Geminga, a neutron star. Gemini also includes a star object known as Messier 35 or M35. The Messier objects are a set of 110 astronomical objects first cataloged in 1771 by French astronomer Charles Messier.

Mythology

Gemini constellation represents the twins Castor and Polydeuces in Greek mythology. The brothers were also known as the Dioscuri, which means “sons of Zeus.” In most versions of the myth, however, only Polydeuces was Zeus’ son, and Castor was the son of the mortal King Tyndareus of Sparta.

The twins’ mother, Spartan Queen Leda, was raped by Zeus, who visited the queen in the form of a swan, associated with the constellation Cygnus (the Swan), and she became pregnant with Polydeuces and Helen (who would become the famous Helen of Troy). Leda later also became pregnant with Castor and Clytemnestra (who would later marry Agamemnon and eventually murder him and be killed by her own son Orestes). Castor and Clytemnestra were fathered by Tyndareus and, unlike Zeus’ children, they were mortal.

Reference: space.com