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.

2011 December 12
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

An Unusual Vein of Deposited Rock on Mars
Image Credit: Mars Exploration Rover Mission, NASA, JPL, Cornell; Image Processing: Kenneth Kremer, Marco Di Lorenzo

Explanation: What could create this unusual vein of rock on Mars? A leading hypothesis is that this thin rock layer dubbed "Homestake" was deposited by a running liquid -- like most mineral veins are here on Earth. And the running liquid of choice is water. Therefore, this mineral streak -- rich in calcium and sulfur -- is the latest in the growing body of evidence that part of Mars had a watery past. This, in turn, increases the speculation that Mars was once hospitable to life. Pictured above is a vista taken near the western rim of Endeavour Crater by the Opportunity rover currently exploring Mars. The inset image shows a close up of the recently discovered mineral vein.

Browse or share: Latest lunar eclipse pictures
Tomorrow's picture: star cone

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

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
NASA Web Privacy Policy and Important Notices
A service of: ASD at NASA / GSFC
& Michigan Tech. U.