December: Mars and Meteors

December, 2009

Mars and Meteors

By Calvin L. Chrisman

I was lying in a sleeping bag in my yard at 1:00 a.m. recently. I was trying to stay warm and awake while watching the Leonids Meteor Shower. The shower was a little slow from our position on the East Coast, so I had time to notice that Mars is beginning to get bigger and brighter. (No, it’s not going to be as big as the full moon. That’s an Internet myth). To the naked eye, Mars never gets to be more than an orange-red point of light, but it can be strikingly noteworthy. It is on its way at the moment.

Mars’ orbit is highly elliptical and it moves closer to Earth every 2.1 years. This close approach is called opposition. The closeness of its approach varies over about 16 years and we are approaching the time when its closest point will be farthest away in the cycle. Sorry – I know that sounds confusing, but think of looking from above the Solar System and making dots in the sky each time Mars gets close to the Earth. Recently, the dots have been moving apart and will continue to do so until the next opposition in 2012. After that, the dots will get closer with a peak in July 2018. Even though this opposition will not be as close as some, the planet will still be bright and beautiful, making its closest approach at the end of January 2010. Currently, Mars is rising around midnight, but by the end of the month it will be rising in the east by 10:00 p.m. It can be found following along behind Gemini, the twins, and just ahead of Leo the lion. It will rise earlier and earlier as 2010 begins and will be close and bright through the early part of April.

Speaking of meteor showers, the conditions should be perfect this month for the Geminid shower as long as the weather cooperates. The shower will peak around midnight on the night of December 13-14, although activity may be seen a night or two on either side of these dates. The Moon will be almost new, so there will be no light interference, making even faint meteors visible. The Geminids usually are at least as good as, if not better than, the Perseids in August. The only issue is that it is a bit colder in December! So, going back where we started, get a warm sleeping bag, bundle up and go lie outside around midnight. The shower is called the Geminids because the tails of the meteors will point back to the constellation Gemini (its two brightest stars are Castor and Pollux, the twins). You do not need to focus on Gemini. A meteor shower is an all-sky phenomenon, so watch broadly across the sky and you should see as many as one to two meteors per minute if your sky is dark enough and there are no clouds. If you are into photography, try taking some time exposures and see if you can create a masterpiece.

Clear Skies

Leave a Comment