[extropy-chat] brine on Mars might have been found

[Damien Broderick]

http://www.theage.com.au/articles/2004/01/22/1074732523467.html

By John von Radowitz
January 22, 2004 - 2:29PM

Pictures from NASA's roving Mars buggy have astonished scientists by
indicating that it may have landed in mud.

Strange marks near the Spirit rover's landing site suggest that against all
the odds there be might liquid water on or just beneath the surface of Mars.

The water would have to be very salty to avoid freezing or evaporating in
the harsh Martian conditions.

If the scientists' suspicions are confirmed it would be the clearest sign
yet that lakes and oceans once existed on Mars, and greatly increase the
chances of life.

The presence of water in the Martian soil could even mean that the Viking
Mars landers really did detect life on the planet in 1976.

Positive results from the Viking experiments were dismissed when it was
realised they could have been produced by an inorganic chemical process. But
mud on Mars would rule out this explanation for the strange findings.

The mystery stems from a small disturbed patch of ground very close to the
lander, New Scientist reported today.

Dubbed the "magic carpet", it was made by the lander's airbags scraping
across the soil.

But its appearance has taken scientists completely by surprise. Instead of
breaking or cracking, as dry soil would be expected to do, the surface seems
to have flowed and folded as if wet.

Science team leader Steven Squyres said: "It looks like mud, but it can't be
mud."

Pure water cannot exist at the low temperatures and pressures found on
Mars - it would either freeze or evaporate away.

But scientists say that is not true of brine. If the water contained enough
salt, it could be stable.

Another member of the Spirit science team, David Des Marais, told New
Scientist: "If it's not pure water, brines should be considered. We know
there are some brines that are stable under these conditions."

He suggested that if past bodies of water on Mars evaporated, the remaining
liquid would become more and more salty until it was briny enough to be
stable.

Other possible explanations for the "muddy" soil include electrostatic
attraction between the dust grains, ice melting on contact with the airbag,
or a tiny amount of moisture released from the airbag.

But other scientists have suggested that seeping surface water may be
responsible for thousands of mysterious gullies seen on the steep slopes of
craters and canyon walls.

Spirit's first microscope image of Mars dirt also revealed puzzling
features - hollow spheres and tubes - that could have been created by salty
deposits.

This is consistent with the idea that a lake which once filled the Gusev
crater, where Spirit landed, dried up leaving a layer of very concentrated
brine.
- PA