Enjoying EarthSky? Subscribe.

110,377 subscribers and counting ...

Moon in Gemini, radiant of Geminid meteors, on December 8

2014-dec-8-castor-pollux-gemini-moon-night-sky-chart

Tonight for December 8, 2014

Tonight, the big and bright waning gibbous moon shines directly in front of the constellation Gemini the Twins, the radiant point for the Geminid meteor shower. Our chart today shows the view in the east-northeast sky for about three hours after sunset.

Gemini’s two brightest stars are Castor and Pollux. They shine quite close to the moon tonight. The star Castor pretty much aligns with the radiant point of the Geminid meteor shower, which is going on right now and is expected to peak in activity on the nights of December 12-13 and 13-14.

Fortunately, the Geminid meteor shower will be at its best this coming weekend, featuring 50 or more meteors per hour in a dark sky. The waning gibbous and last quarter moon on the weekend won’t be nearly as obtrusive as tonight’s moon. Friday and Saturday evenings will present moon-free skies for meteor watching, so start observing the Geminid meteors around 9 p.m. The Geminids fall most prolifically in the wee hours after midnight, centered around 2 a.m. local time. Although the moon will be up in the morning hours, the Gemind meteors are often bright and a good number of them can be expected to overcome the light of the moon.

Radiant point for December’s meteor shower

Castor and Pollux, the Twin Brothers of Greek mythology

This evening, on December 8, watch for the moon and Gemini to swing westward throughout the night, for the same reason the sun moves westward during the day. It’s because the Earth rotates eastward on its axis. Therefore, all the heavenly bodies – the sun, moon, planets and stars – appear to travel westward across the sky while the Earth remains at rest. But it’s really the earth that’s doing the moving. The moon, Castor and Pollux climb high overhead after midnight, and swing into the western sky by dawn.

Photo credit: ketrin1407

According to Greek sky lore, Castor and Pollux were twin brothers, born from Leda, their mortal mother, and sired by Zeus, the immortal god. Though the brothers were united in spirit, they were divided by circumstance. Castor, the mortal, was slain in battle, leaving his immortal brother inconsolable with grief. Pollux asked Zeus to release him from immortality, so he could join his brother in the great beyond.

Today, the Gemini Twins stand together in the heavens, a testament to the redemptive power of brotherly love.