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The (1) Phoenix lander's first taste test of soil near Mars' north pole reveals a briny environment similar to what can be found in backyards on Earth, scientists said. The finding raises hope that the Martian arctic plains could have conditions favorable for primitive life.
"There's nothing about it that would preclude life. In fact, it seems very friendly," mission scientist Samuel Kounaves of Tufts University said of the soil. "There's nothing about it that's toxic."
Phoenix so far has not detected organic carbon considered an essential building block of life. Last week, the lander found evidence of ice below the soil. Scientists generally agree that liquid water, a stable energy source and organic, or carbon-containing, compounds are required for a habitable zone.
Earlier this week, Phoenix's 8-foot (2-meter)-long robotic arm delivered a pinch of dirt dug up from near the surface to its onboard lab. Like a chemist, the spacecraft mixed the soil with water brought from Earth into a beaker the size of a teacup and stirred it. Sensors inside the beaker detect the soil's pH and probe for traces of the nutrients. Preliminary results showed the soil had a pH between 8 and 9, researchers said. A pH less than 7 means the solution is acidic, while a pH over 7 means it is alkaline. Phoenix also detected the presence of magnesium, sodium, potassium and chloride in the mixture. "It's very typical of the soil here on Earth minus the organics," Kounaves said. On Earth, asparagus, green beans and turnips could be planted in such an environment and chemical-loving bacteria would thrive there, he said. Planetary scientist David Paige of the University of California, Los Angeles, said it is too early to tell whether the minerals found in the soil could support life. Paige. who had no role in the mission, said the find was not surprising because rocks weather over time and bits of minerals mix with the soil. ■AP
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