Mars Soil Resembles Veggie-Garden Dirt, Lander Finds

Richard A. Lovett
for National Geographic News
June 26, 2008

Soil near the north pole of Mars is surprisingly Earthlike, with a pH not unlike many vegetable gardens, according to preliminary results from the Phoenix Mars Lander.

"You might be able to grow asparagus in it, but strawberries, probably not very well," said Samuel Kounaves, a chemistry professor at Tufts University, during a NASA press conference this afternoon.

Previous data from the two rovers exploring Mars's equatorial zones had suggested that the geochemistry on the red planet might have been too acidic to support most forms of Earth-type life.

But as little as an inch (2.5 centimeters) beneath the surface, dirt from Mars's arctic plains proved to be very similar to alkaline soils on Earth, with a pH between 8 and 9. The pH scale goes from 0 (acidic) to 14 (alkaline).

The finding is good news in the hunt for signs that Mars was or could now be habitable.

"This means there is a broader range of organisms that can grow [in it]," said Kounaves, who works with the lander's Microscopy, Electrochemistry, and Conductivity Analyzer (MECA).

"But Mars is a huge place, whose soils might differ radically from spot to spot," Kounaves said. "We have to remember that we're looking at tiny areas."

Shake and Bake

The MECA team also found that the soil contains magnesium, sodium, potassium, and chloride.

While these are all key nutrients, the tests don't reveal everything needed for life.

For example, the test looked only at inorganic nutrients, not organic compounds, and it didn't look at all of the dozens of potentially important trace nutrients.

Still, said MECA team leader Michael Hecht of NASA's Jet Propulsion Laboratory, "it's a huge step forward."

Continued on Next Page >>




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