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Moon and Companions

March 17, 2014

The Moon and a couple of bright companions put on quite a show the next couple of nights. They climb into good view by late evening and are low in the southwest at first light. Spica, the brightest star of Virgo, stands almost directly below the Moon as they rise tonight, with brighter orange Mars close to the left of Spica.

Mars is just about at its orangey best right now. Earth is catching up to it in our smaller, faster orbit around the Sun. We’ll pass by the planet in about three weeks, so Mars will line up opposite the Sun in our sky. It’ll be in view all night, and will shine at its brightest. In fact, only the Moon and a couple of other planets will outshine it.

Mars’s brilliance will highlight the planet’s color. Although it’s known as the “red” planet, its overall color is more orange than red. Large sections of its surface are gray volcanic plains. But other sections are coated with orange dust that’s rich in iron oxide — rust. It formed when iron-rich minerals interacted with water in the distant past.

The dust is found across much of Mars. In some places, it forms dunes that stretch for many miles. In others, it settles atop mountains and craters, giving them an orange veneer. The wind sometimes blows the dust away. At other times, though, it stirs up giant storms that carry dust across thousands of miles — sometimes covering almost the entire planet.

More about the Moon and its companions tomorrow.


Script by Damond Benningfield, Copyright 2014

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