Mars is taking careful aim at Saturn, and the red planet is expected to pass within a half-degree of the famous ringed planet in mid-June. But don't worry -- there's no danger of a collision between the two massive masses. Although they will appear very close together in our sky, their apparent near-miss is an illusion. Saturn will be at a safe distance of more than 700 million miles from Mars. They just happen to occupy the same line of sight when viewed from earth.
The two planets will appear closest on June 17, but there's no need to wait until then to enjoy this showdown at sundown. Watching the gap between the planets shrink night by night is the most exciting part. Adding to the beauty of this cosmic event is the famous naked-eye star cluster known as the Beehive, which will be in the same binocular field as the two bright planets.
Here's how to locate the two planets and enjoy the show:
Go outside and face west -- the direction that the sun went down --t about 10 p.m. You'll see a number of bright objects in that part of the sky. Saturn will be one of the brightest, about a third of the way from the horizon to the overhead point. To Saturn's lower right will be three bright objects. The two on the right, sitting side by side, are the Gemini Twins, Castor and Pollux. Mars is the third object, positioned between the Gemini Twins and Saturn. Mars is relatively faint right now because it is so far away from earth, but it's ruddy hue should give it away.
If you watch from night to night, you'll see Mars pull even with Castor and Pollux, eventually forming a straight line Tuesday night, the same night that a slender crescent moon will be smiling at us exactly between Mars and the Gemini Twins. Don't miss this beautiful alignment.
The next night, Wednesday, the crescent moon will be positioned right above Saturn, another don't miss celestial show. On Wednesday, Saturn and Mars will be about 8.5 degrees apart. By June 13, Mars will have moved to within two degrees of Saturn, and the beautiful Beehive cluster will be smack dab in between the two dazzling planets, flanking it on each side. Use binoculars to fully appreciate this marvelous alignment.
On June 15, Mars will be within the swarming Beehive, surrounded by glittering stars. Two nights later, on June 17, Mars and Saturn will be as close together as they will get, about a half degree -- or about the apparent width of the full moon. After that, Mars and Saturn will switch places in the sky, and Saturn will slowly sink into the multi-colored sunset night by night.
After watching this amazing planetary parade, you will be able to fully appreciate why the Greeks called these particular objects "planets," which means "wandering stars."
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. He is an avid astronomer whose photographs and articles have been published on the Web sites of CNN.com, NASA's "Astronomy Picture of the Day," Spaceweather.com, Space.com, Discover.com, and in Sky & Telescope, Astronomy, Night Sky, Discover, and WeatherWise magazines.