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.

2004 December 15
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Looking Back Over Mars
Credit: Mars Exploration Rover Mission, JPL, NASA

Explanation: Pictured above, the path of the robot rover Spirit on Mars can be traced far into the distance. Spirit has now crossed kilometers of plains covered with rocks and sand, approached the lip of a crater 200-meters across, and climbed a series of hills. Spirit's path has been not only one of adventure but discovery. Landing inside vast Gusev crater near the beginning of this year, Spirit, along with its sister robot Opportunity across the planet, has uncovered key evidence for ancient Martian water. The recent discovery of goethite, a mineral only known to form on Earth in the presence of water, bolsters the case. Spirit and Opportunity continue to roam the red planet in search of different and more detailed clues to the unfolding ancient past of Mars.

Tomorrow's picture: barred spiral

< | Archive | Index | Search | Calendar | Glossary | Education | About APOD | >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.