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Moon and Companions

October 10, 2010

Like a referee in the middle of a boxing ring, the crescent Moon stands about halfway between two rivals tonight: the planet Mars and the star Antares. They're low in the southwestern sky as darkness begins to fall. Antares is to the upper left of the Moon, with Mars a little farther to the lower right of the Moon.

The "rivalry" between these two bodies is based on their color: orange.

Mars was named for the ancient god of war because its color is like that of blood -- especially when the planet is at its brightest.

Antares is the same color, so it was named with the war god in mind, too. "Ares" was the Greek version of the god, and "anti" means "against" or "rival of." So the star's name means "rival of Mars."

Of course, any rivalry between a planet and a star is pretty lopsided. Mars is a relatively small chunk of rock -- about half the diameter of Earth. Antares, on the other hand, is not just a star, it's a super star. It's so big that if it took the Sun's place in our solar system, it would extend all the way out beyond the orbit of Mars -- swallowing its rival like a speck of cosmic dust.

Look for the two rivals flanking the crescent Moon early this evening. Mars is lower in the sky, so it's tougher to find; binoculars will help you pluck it from the fading twilight. Antares is a little higher, and it sets around an hour later, so you shouldn't have any trouble finding it.

More about Antares tomorrow.


Script by Damond Benningfield, Copyright 2010


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