[meteorite-list] Conditions On Vast Plain on Mars Could Have Been Suitable For Life

[Ron Baalke]

http://www.news.cornell.edu/releases/Dec04/Science.Mars.deb.html

Conditions on vast plain on Mars could have been suitable for life, 
Cornell rover scientist Squyres states in special Science issue

FOR RELEASE: Dec. 2, 2004

Contact:  David Brand
Office:  607-255-3651
E-mail:  deb27 at cornell.edu

ITHACA, N.Y. -- Scientists have long been tantalized by the question 
of whether life once existed on Mars. Although present conditions on 
the planet would seem to be inhospitable to life, the data sent back 
over the past 10 months by NASA's two exploration rovers, Spirit and 
Opportunity, showed a world that might once have been warmer and 
wetter -- perhaps friendly enough to support microbial organisms.

Now a Cornell University-led Mars rover science team reports on the 
historic journey by the rover Opportunity, which is exploring a vast 
plain, Meridiani Planum, and concludes with this observation: "Liquid 
water was once present intermittently at the martian surface at 
Meridiani, and at times it saturated the subsurface. Because liquid 
water is a key prerequisite for life, we infer that conditions at 
Meridiani  may have been habitable for some period of time in martian 
history."

The article is one of 11 published this week (Dec. 3, 2004) in a 
special issue of the journal Science, authored by scientists 
connected with the Mars rover mission, several from Cornell and from 
the Jet Propulsion Laboratory in Pasadena, Calif., the mission's 
manager. The issue covers Opportunity through its first 90 days of 
exploring its landing site of Eagle crater in Meridiani Planum. This 
was before the rover drove to and entered the large crater dubbed 
Endurance, from which it is now about to emerge.

Steve Squyres, Cornell professor of astronomy and leader of the 
rovers' Athena science team, is the lead author of the main paper, 
"The Opportunity Rover's Athena Science Investigation at Meridiani 
Planum, Mars." In another paper, on which he is also the lead author, 
Squyres again refers to the geological record at Meridiani Planum as 
suggesting that conditions were suitable for "biological activity" 
for a period of time in the history of mars. In the article, "In Situ 
Evidence for an Ancient Aqueous Environment at Meridiani Planum, 
Mars," he writes: "We cannot determine whether life was present or 
even possible in the waters at Meridiani, but it is clear that by the 
time the sedimentary rocks in Eagle crater were deposited, Mars and 
Earth had already gone down different environmental paths. Sample 
return of Meridiani rocks might well provide more certainty regarding 
whether life developed on Mars."

The Mars rover mission is not designed to look for microbial life but 
to look for evidence of whether conditions were once right for life. 
As Squyres recently stated, "What we were seeking was rocks that were 
actually formed in liquid water so that we could read the record in 
those rocks, not just to say liquid water was on Mars but to learn 
something about what the environmental conditions were like, would 
they have been suitable for life and, importantly, do the minerals 
that were formed have the capability to preserve for long periods of 
time evidence of former life? That's probably the single most 
important thing we have found: evidence for minerals at Meridiani 
that are the kinds of things that are very good at preserving 
evidence of ancient life for very long periods of time."

Opportunity bounced down on Jan. 25, 22 days after its twin, the 
rover Spirit, landed on the opposite side of Mars in Gusev crater. 
Last August Science published a special issue on Spirit.

"This is the first peer-reviewed presentation of the data from 
Opportunity," notes Jim Bell, Cornell associate professor of 
astronomy and the lead scientist for the rovers' Pancam color imaging 
system.

Bell also is prominent in the special issue of Science, including his 
lead authorship of a paper, "Pancam Multispectral Imaging Results 
from the Opportunity Rover at Meridiani Planum."

When Opportunity landed on the red planet last January, the robot 
geologist sent back images of its landing site that were unlike any 
of the other places where earlier lander probes and rovers had gone. 
Instead of rusty deserts of dusty soil and boulders strewn to the 
horizon, Opportunity had landed in a relatively small crater in a 
vast sea of sand nearly devoid of rocks. Fortunately, an intriguing 
outcrop of bedrock presented itself nearby, which scientists hoped 
would be a sample of the original crust underneath the layers of dust.

The scientists were not disappointed. Scattered among the outcrop 
rocks were large numbers of small, round mineral deposits that the 
Athena science team named "blueberries." On Earth, such formations 
appear when large amounts of water course through rock layers, 
leaching out the iron--bearing minerals into small spherical rocks 
and granules. The rovers also detected large amounts of sulfate salt 
deposits.  Enough evidence was collected by Opportunity in the two 
months it spent examining Eagle crater that the science team felt 
confident enough to announce in early March that liquid water had 
flowed over the crater's rocks long ago, possibly for a long time. 
Following on this, the latest Science articles largely focus on 
Opportunity's most important scientific and geological 
accomplishment: the discovery of evidence that liquid water once 
flowed through the region.

Like the coverage given to Spirit in the August issue of Science, the 
latest edition contains several foldouts with big color panoramas and 
images from Opportunity's region of exploration.

Freelance writer Larry Klaes contributed to this report.

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