Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2006 January 26
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An Unusual Two-Toned Rock on Mars
Credit: Mars Exploration Rover Mission, Cornell, JPL, NASA

Explanation: How did this unusual Martian rock form? The atypical two-toned rock, visible in the lower right of the above image, was photographed a few days ago by the robotic Spirit rover currently rolling across Mars. For now, the environmental processes that created the rock remain a matter of speculation. Finding unusual rocks is not unusual for Spirit or its twin rover Opportunity, however. Over the past two years, for example, the rovers have unexpectedly discovered very small gray pebbles dubbed blueberries, and a rock out in the middle of nowhere now thought to be a meteorite. Having investigated alien terrain and having found clear evidence that part of Mars had a wet past, the Earth-launched Martian rovers are now entering their third spectacular year exploring the red planet.

Tomorrow's picture: storm on Saturn

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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NASA Official: Jay Norris. Specific rights apply.
A service of: EUD at NASA / GSFC
& Michigan Tech. U.