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Brilliant Venus

February 13, 2014

The “morning star” is shining at its dazzling best right now. It’s in the southeast at first light. It’s quite low, but if you have a clear horizon you shouldn’t have any trouble picking it out, because it far outshines all the other planets and stars in the night sky.

This brilliant beacon is Venus, our closest planetary neighbor. It passed between Earth and the Sun last month, and it’s pulling away from us in its smaller, faster orbit around the Sun.

As it does so, sunlight illuminates more of the hemisphere that faces our way. Right now, the combination of distance and illuminated fraction are such that Venus shines at its brightest. Over the coming months, more of the planet’s visible disk will be in sunshine, but Venus will also be farther from Earth, so it’ll grow a bit fainter. But it’ll still be the brightest night-sky object other than the Moon, so you can’t miss it.

Venus’s phases were discovered by Galileo Galilei, who was born 450 years ago this week. He was the first to turn a telescope toward the heavens. Among other wonders, he saw that Venus went through a cycle of phases, just as the Moon does. His discovery confirmed that Venus orbits the Sun, placing our star at the center of the solar system instead of Earth.

And if you have your own telescope, you can see that evidence yourself. Venus is a thick crescent now, with about a quarter of its disk in sunlight — making the planet shine at its most brilliant.

Script by Damond Benningfield, Copyright 2013

Note: An earlier version of this program indicated that Galileo's birthday is February 13. It is February 15.

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