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Icy Mars

October 11, 2013

At the surface, Mars is a desert world, its surface coated with a powdery orange sand that blows in the Martian winds. Dig just below the surface, though, and it’s a different story. Vast deposits of frozen water are found across much of the planet — perhaps more water than is found in the polar ice caps.

The Phoenix lander found almost pure water ice when it scraped just an inch or two below the surface. And radar aboard a Mars orbiter has found buried glaciers that may be hundreds of feet thick and cover hundreds of square miles.

The glaciers are in the middle latitudes of both the northern and southern hemispheres. Many of them are found hugging the sides of tall mesas, and they’re covered with a few feet of dirt. The radar observations show that the glaciers are almost pure ice, with little dirt or rocks mixed in.

The glaciers may have formed when Mars was tilted more severely than it is today. Water in the polar ice caps vaporized and moved toward the equator. The water condensed and fell to the ground as heavy snow, forming thick beds of ice. As the planet returned to a more gentle tilt, the ice was covered by blowing sand and dust — preserving vast glaciers beneath the Martian desert.

And Mars is in good view in the pre-dawn sky. It’s high in the east at first light, and looks like a fairly bright orange star. The true star Regulus, the leading light of Leo, is just below it, forming a beautiful duo with the “icy” Red Planet.


Script by Damond Benningfield, Copyright 2013

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