8/10/2019 Curiosity Finds a Once Habitable Mars

1/2

Curiosity Finds a Once Habitable Mars

NASA's newest rover is finding that the floor of Gale crater is quite ancient and provided an

envir onmental niche quite conducive to microbial l if e.

The researchers coordinating NASA's $2.5 billion Mars Science Laboratory have always beencareful to note that their beefy Curiosity rover is not searching for life on the Red Planet. Rather,it's designed to find out whether Mars was ever suitable for life.

After a year of zapping, scratching, sniffing, and tasting rocks and sand near the rover's landingsite, the answer is "yes." A flurry of findings published in the December 9th issue of Science,simultaneously announcedat December's meeting of the American Geophysical Society, providethe best evidence yet that ancient Mars was indeed habitable.

Curiositys Mast Camera recorded this view of sedimentary deposits inside Gale crater inFebruary 2013. The mudstone ledge at lower right is about 20 cm (8 inches) high. Clickherefora larger view.NASA / JPL-Caltech / MSSSCuriosity dropped onto the broad floor of Gale crateron August 6, 2012,then spent manymonths exploring intriguing rocky outcrops in a nearby expanse dubbed Yellowknife Bay.Mission scientists soon realized that much of the terrain was covered in mudstone, siltysediments that settled onto the bottom of an ancient lake.

What's now clear, as reported by one research team led by project scientist John Grotzinger(Caltech) and a second by David Vaniman (Planetary Science Institute), is that the sediments

contain an iron- and sulfur-rich clay called smectite. Moreover, this clay formed in water with aneutral pH and low salinityjust the kind of benign habitat that primitive life forms calledchemolithoautotrophs would want. Such microbes derive their energy from the oxidation ofinorganic compounds and their carbon from atmospheric carbon dioxide.

A separate analysis by Kenneth Farley (Caltech) and others used isotopic ratiosnevermeasured before by a Martian landerto estimate the age of a mudstone slab nicknamedCumberland. It's between 3.86 and 4.56 billion years old, confirming that Gale crater formed

http://mars.jpl.nasa.gov/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1565http://mars.jpl.nasa.gov/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1565http://photojournal.jpl.nasa.gov/jpegMod/PIA17603_modest.jpghttp://photojournal.jpl.nasa.gov/jpegMod/PIA17603_modest.jpghttp://photojournal.jpl.nasa.gov/jpegMod/PIA17603_modest.jpghttp://www.skyandtelescope.com/news/Touchdown-Curiosity-Lands-in-Gale-Crater-165101446.htmlhttp://www.skyandtelescope.com/news/Touchdown-Curiosity-Lands-in-Gale-Crater-165101446.htmlhttp://www.skyandtelescope.com/news/Touchdown-Curiosity-Lands-in-Gale-Crater-165101446.htmlhttp://www.skyandtelescope.com/news/Touchdown-Curiosity-Lands-in-Gale-Crater-165101446.htmlhttp://photojournal.jpl.nasa.gov/jpegMod/PIA17603_modest.jpghttp://mars.jpl.nasa.gov/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1565

8/10/2019 Curiosity Finds a Once Habitable Mars

2/2

very early in Martian history.

But Farley and his team also tested for elemental isotopes produced by the potent cosmic raysthat constantly bombard the Martian surface. Cumberland's "exposure age" is comparativelyyoung, only 60 to 100 million years. Apparently the sediments in Yellowknife Bay spent eons

buried under the protective cover of overlying material, which eventually was stripped away bythe planet's incessant winds only in the recent geologic past.

Biologically speaking, this is great news. It means the rover has at least a chance to detectorganic matter that might have become trapped in these ancient sediments. In fact, a researchteam led by Douglas Ming (NASA Johnson Space Center) reports that Curiosity continues todetect chlorinated hydrocarbons in samples of the Martian surface - and that it can't all becontaminants brought from Earth. Instead, these simple organics might be indigenous to Mars orelse hitchhiked there inside meteorites.

In an unusual move for Science, all six of its just-published Curiosity articles arefreely available

online.You can alsowatch a press briefingheld during the AGU meeting.

Posted by kbeatty@SkyandTelescope.com, December 13, 2013

http://mars.jpl.nasa.gov/msl/mission/science/researchpapers/http://mars.jpl.nasa.gov/msl/mission/science/researchpapers/http://mars.jpl.nasa.gov/msl/mission/science/researchpapers/http://mars.jpl.nasa.gov/msl/mission/science/researchpapers/http://mars.jpl.nasa.gov/msl/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1564http://mars.jpl.nasa.gov/msl/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1564http://mars.jpl.nasa.gov/msl/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1564http://mars.jpl.nasa.gov/msl/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1564http://mars.jpl.nasa.gov/msl/mission/science/researchpapers/http://mars.jpl.nasa.gov/msl/mission/science/researchpapers/