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Close this windowPosted on 01/22/2004 1:05:13 AM PST by ambrose
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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.
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Did Spirit land in a mud patch? |
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.
In 1976, the two Viking landers conducted experiments in which Martian soil was mixed with a nutrient soup containing a radioactive marker. Both tests produced radioactive gas, as would be expected if alien microbes were metabolising the nutrients.
However the excitement of finding life on Mars faded when scientists realised that the same effect could be caused by strong oxidants in the soil.
Gilbert Levin, who designed the test, believes Spirit's "magic carpet" images prove that the Viking probes really did detect life.
"If there is liquid water in the soil, the strong oxidant cannot be there, since liquid water, or even just the vapour from it, would destroy the oxidant," he told New Scientist.
Spirit will not be able to study the magic carpet area directly since it is too close to the landing platform, creating a potential hazard for the rover.
But whatever caused the strange patch of soil will probably be found elsewhere. The Spirit scientists hope to make new marks by using one of the rover's wheels to dig into the soil, or by rotating the wheel sideways.
- PA
This story was found at: http://www.theage.com.au/articles/2004/01/22/1074732523467.html
Mud's not so bad.
Indeed. Of course, we've known there is ice at the poles on Mars since Lowell's 19th Century observations of the Red Planet. But this is indeed major news.
Its time to go there (warmly dressed, of course).
Note to self: Book a side trip to LL Bean for sleeping bags and a decent expedition tent, THEN go :)
NO, it's to cold for mud. it would be ice.
Hmm. Atmosphere 7 millibars. Temperature -170 to 0. Atmospheric oxygen = 0. Sounds like it could support "a human colony" to me. < /sarcasm>
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