Two Planets Will Provide Christmas Sky Vision

On the night of December 21st, the giant planets Jupiter and Saturn will appear to merge in the night sky in what is called a Great Conjunction, possibly creating a rare very bright "star." Astronomers have been abuzz on the internet about this Christmas view which is a close approach between the two planets from our view here on Earth. Actually, the planets are very far away from each other (and us) as they orbit the Sun. Jupiter is 93 million miles away from us and Saturn is about 900 million miles away. But in the sky, leading up to December 21, they are getting closer and closer as Jupiter catches up to Saturn.

Now, our eyes play tricks on us - as we know when the moon appears gigantic as it comes up in the early evening and then looks much smaller as it crosses above us. That might affect the view of the two planets and they might not look as close to each other as people are expecting. But still, they haven't been this close in the sky since the year 2000. The distance between them is going to be about one-fifth of a full moon. That sort of separation won't happen again until 2080. Right now, the two planets are in the South after sunset and move across the sky all night long as Jupiter tries to catch up to Saturn.

Also starting tonight is the annual Geminids meteor shower, which can be as active as 120 meteors an hour. Right now, the moon is pretty bright, washing out the dim meteors, but the peak of the shower is December 13-14, when the moon is not a factor. All we worry about then are clouds...and the cold weather. Dress in layers.