The Goat

As always, the stars of three seasons are in the tonight's sky. About to set in the west are thestars of the summer triangle: Vega, the brightest; Deneb, the most distant; and Altair. High is the east is the great square of Pegasus, the autumn square. And just now rising in the east is brilliant Capella, the first corner of the winter hexagon.

Like many of the stars in the sky, Capella is part of a multiple star system; the two main components are stars equally bright, one yellow, one red. Each more than fifty times as luminous as the Sun, they are closer to each other than the Sun is to Venus. If we were circling one of them, we would see two suns in the sky, one yellow, one red. There are two other members of the Capellan star system, but they are so far away from the primary stars that to someone circling Capella they would just look like bright stars.

Capella is the "goat star." She was was the goat that suckled the infant Zeus; there are three pinpoints of light under Capella; one is Zeus, the other two are her "kids." The three look like diamonds through a pair of binoculars.

Later generations saw Capella as the lame king of Athens, Erichthonius, to whom they dedicated the Erechtheum. Erichthonius invented the chariot, and because of this invention, when he died he was placed in the sky by Zeus. The atars around Capella form his chariot, and he is the charioteer -- Auriga, in Latin.

And that brilliant starlike object that just set in the west was Zeus himself - the planet that we call by his Roman name - Jupiter.

(10/09/07)