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 December 12
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Light Deposits Indicate Water Flowing on Mars
Credit: Mars Global Surveyor

Explanation: What's creating light-toned deposits on Mars? Quite possibly -- water! Images of the same parts of mid-latitude Mars taken over the years but released only last week have shown unexpected new light-toned deposits where there were none before. One clear case is shown above, where the same crater on Mars is shown as photographed in 1999 August and again in 2005 September. The unusual deposit is visible only on the more recent photograph. Apparent tributaries near the bottom bolster the leading hypothesis that water gushed out of the crater wall, flowed down the crater, and soon evaporated into the thin Martian atmosphere. Although frozen water-ice has been known near the Martian poles for years, free flowing surface water like this was not expected to be seen in the mid-latitudes of Mars. If confirmed, such water springs might make more of Mars hospitable to life and human visitation than previously believed.

Tomorrow's picture: solar tsunami

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

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