Sneaking Up on Mars

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The Moon is sneaking up on Mars tonight. Both are part of an impressive lineup that stretches from the twins of Gemini to the heart of the lion.

As night falls, look for Mars to the left of the Moon, and a little higher in the sky. It looks like a fairly bright orange star.

Mars and the Moon are separated by around 13 or 14 degrees tonight -- a little more than the width of a fist held at arm's length. But the Moon is moving eastward against the background of stars -- in the direction of Mars. It moves about 13 degrees every 24 hours. So at nightfall tomorrow, the Moon and Mars will stand within about a degree of each other.

It takes the Moon 27 and a third days to complete a full circle around the sky, and return to the same position against the stars. But Mars and the other planets move against the stars, too, so the number of days it takes the Moon to catch up to each planet varies. It depends on how fast the planet is moving, and in which direction. Mars is moving eastward right now, just like the Moon, and at a good clip. So it'll take the Moon a couple of extra days to catch it again.

Mars and the Moon are the middle of a bright array tonight. To the right of the Moon, look for Pollux and Castor, the "twin" stars of Gemini. And about the same distance to the upper left of Mars are the planet Saturn and the star Regulus, the "heart" of Leo, the lion. The Moon will sneak up on them in a couple of nights.

Script by Damond Benningfield, Copyright 2008

For more skywatching tips, astronomy news, and much more, read StarDate magazine.