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Moon and Companions

April 16, 2011

If you could stroll along the banks of a riverbed in Xanadu, you'd see an orange sky overhead, with a morning drizzle falling from high clouds. Still lakes might glimmer in the distance. And in the riverbed below, rounded stones would sparkle like giant rhinestones, glittering ahead of you like an enchanted pathway beckoning Dorothy to the city of Oz.

You might want to bundle up, though; this enchanted land is on Saturn's giant moon Titan, where temperatures hover around 300 degrees below zero Fahrenheit, and the glittering stones are made of ice that's frozen as hard as granite.

Xanadu is a bright region in Titan's southern hemisphere that's as big as Australia. It's criss-crossed by channels that were probably carved by rivers of liquid methane and ethane, or by eruptions of water and ice from frigid volcanoes. Many of the channels empty into lakes.

As the rivers flow downhill, they tumble chunks of ice, rounding them off and polishing their surfaces. These clear iceballs would sparkle in the faint sunlight at Titan's surface. They help make Xanadu one of the brightest regions on the entire moon -- and one of the most intriguing, too.

Saturn is near our own Moon tonight, shining like a bright golden star. They're low in the sky as darkness falls, forming a beautiful triangle with the star Spica. Saturn is to the upper left of the Moon, with Spica a little farther to the lower left.

More about the Moon and Spica tomorrow.

Script by Damond Benningfield, Copyright 2011


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