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Like the Ancient Mariner in the poem by Coleridge, the Mars rover Spirit seems to be whispering in its electronic voice, "Water, water everywhere ..."
Only a week after its successful landing, Spirit has already detected traces of water in the minerals within range of its instruments. NASA's Jet Propulsion Laboratory website reports that the mini-thermal emission spectrometer aboard Spirit shows the infrared signature of carbonates, which form in the presence of water.
BBC online reports that scientists are not sure whether the carbonates come from water that covered the site, or from vapor in the atmosphere or blowing dust, but the findings will help scientists decide where to send Spirit for further investigations. "We came looking for carbonates. We have them. We're going to chase them," said Dr Phil Christensen of Arizona State University, Tempe, leader of the Mini-Tes team.
NASA chose Gusev Crater as the Spirit landing site because pictures suggest the area may once have been a lake. Water found inside crystals underground would mean that it once flowed freely on the surface. The presence of liquid water is considered key for finding life on Mars, either in living or fossil forms.
Because its front ramp is blocked by a protective airbag, mission controllers plan to rotate Spirit 120 degrees before rolling it down what they hope is a clear path to the ground late Tuesday. Currently the robot is "standing up" on its wheels, ready to roll.
Even parked on its pad, the Spirit has provided a great deal of data to scientists, including stunning color images of the Red Planet, allowing scientists a detailed look at the landing site. Most intriguing are soil marks showing an unusual cohesiveness, almost as if the soil grains were stuck together like mud. Scientist Steve Squyres exclaimed, "The way in which the surface has responded is bizarre. It looks like mud, but it can't be mud."
Sunday's New York Times, in an article by William J. Broad, said "Even if just one little Martian were to come to light, however small and ugly, old and desiccated, its discovery would have ramifications far beyond the scientific. It would suggest that we are not alone in the universe."
Broad quotes Dr. Frank D. Drake, an astronomer at the University of California at Santa Cruz and a pioneer of the hunt for extraterrestrial life, as saying, "Some eminent people say it will be terribly depressing, that we'll feel ignorant, and they predict a planet-wide inferiority complex. My take is that it could have the opposite effect. It could motivate us to think that if we worked hard we could be as good as them, motivate us to make progress much more quickly than we are."
Spirit and its twin Opportunity, which scheduled to land later this month, cannot ultimately perform the chemical tests necessary to prove the existence of life, but in 2009 NASA plans to launch the Mars Science Laboratory, a nuclear-powered roving mobile explorer that will focus on hard chemistry and will be able to roam the Martian terrain for years. Another lander is scheduled as early as 2011 to probe deeper into the ground.
According to the Times article, "If Martian life is found, Earthlings face two very different interpretative hurdles. If there is DNA and protein present, as there are in Earth creatures, then Martian life might be seen as coming from Earth via cosmic collisions that over billions of years sent microbes flying on rocky debris through space like windblown seeds. (Or, an equally possible theory that scientists hold is that all terrestrial life originally came from Mars - that we, in effect, are the Martians.)"
If, on the other hand, Martian life is unlike Earth's, it would suggest "evolution is a cosmic imperative and that living things of one sort or another exist nearly anywhere in the universe. The discovery would give new life to speculations about the existence of sentient beings far more advanced than us."
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