[meteorite-list] Water you talking about?

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Sat, 09 Jun 2007 17:12:29 -0400
Message-ID: <ap5m63tj2n29eodb602vu6v92l0kt6mu11_at_4ax.com>

http://space.newscientist.com/article/dn12026-mars-rover-finds-puddles-on-the-planets-surface.html

Mars rover finds "puddles" on the planet's surface
15:33 08 June 2007
NewScientist.com news service
David Chandler

http://space.newscientist.com/data/images/ns/cms/dn12026/dn12026-2_283.jpg

A new analysis of pictures taken by the exploration rover Opportunity reveals
what appear to be small ponds of liquid water on the surface of Mars.

The report identifies specific spots that appear to have contained liquid water
two years ago, when Opportunity was exploring a crater called Endurance. It is a
highly controversial claim, as many scientists believe that liquid water cannot
exist on the surface of Mars today because of the planet?s thin atmosphere.

If confirmed, the existence of such ponds would significantly boost the odds
that living organisms could survive on or near the surface of Mars, says
physicist Ron Levin, the report's lead author, who works in advanced image
processing at the aerospace company Lockheed Martin in Arizona.

Along with fellow Lockheed engineer Daniel Lyddy, Levin used images from the Jet
Propulsion Laboratory's website. The resulting stereoscopic reconstructions,
made from paired images from the Opportunity rover's twin cameras, show bluish
features that look perfectly flat. The surfaces are so smooth that the computer
could not find any surface details within those areas to match up between the
two images.

The imaging shows that the areas occupy the lowest parts of the terrain. They
also appear transparent: some features, which Levin says may be submerged rocks
or pebbles, can be seen below the plane of the smooth surface.

Smooth surface
The smoothness and transparency of the features could suggest either water or
very clear ice, Levin says.

"The surface is incredibly smooth, and the edges are in a plane and all at the
same altitude," he says. "If they were ice or some other material, they'd show
wear and tear over the surface, there would be rubble or sand or something."

His report was presented at a conference of the Institute of Electrical and
Electronics Engineers, and will be published later this year in the institute's
proceedings.

No signs of liquid water have been observed directly from cameras on the surface
before. Reports last year pointed to the existence of gullies on crater walls
where water appears to have flowed in the last few years, as shown in images
taken from orbit, but those are short-lived flows, which are thought to have
frozen over almost immediately.

Speedy evaporation?
Levin and other reasearchers, including JPL's Michael Hecht, have published
calculations showing the possibility of "micro-environments" where water could
linger, but the idea remains controversial.

?The temperatures get plenty warm enough, but the Mars atmosphere is essentially
a vacuum," says Phil Christensen of Arizona State University, developer of the
Mars rovers' mini-Thermal Emission Spectrometers. That means any water or ice
exposed on the surface evaporates or sublimes away almost instantly, he says.

But, he adds, "it is theoretically possible to get liquid water within soil, or
under other very special conditions". The question is just how special those
conditions need to be, and whether they ever really are found on Mars today.

If there were absolutely no wind, says Christensen, you might build up a
stagnant layer of vapour above a liquid surface, preventing it from evaporating
too fast. ?The problem is, there are winds on Mars
 In the real world, I think
it's virtually impossible," he told New Scientist.

Simple test
Levin disagrees. He says his analysis shows that there can be wind-free
environments at certain times of day in certain protected locations. He thinks
that could apply to these small depressions inside the sheltered bowl of
Endurance crater, at midday in the Martian summer.

He adds that highly briny water, as is probably found on Mars, could be stable
even at much lower temperatures.

Although the rover is now miles away from this site, Levin proposes a simple
test that would prove the presence of liquid if similar features are found: use
the rover's drill on the surface of the flat area. If it is ice, or any solid
material, the drill will leave unmistakable markings, but if it is liquid there
should be no trace of the drill's activity.

Levin?s father Gilbert was principal investigator of an experiment on the Viking
Mars lander, which found evidence for life on the planet, although negative
results from a separate test for organic materials led most scientists to doubt
the evidence for biology.

Journal reference: R. L. Levin and Daniel Lyddy, Investigation of possible
liquid water ponds on the Martian surface (2007 IEEE Aerospace Applications
Conference Proceedings, paper #1376, to be published in IEEE Xplore)
Received on Sat 09 Jun 2007 05:12:29 PM PDT