Scientists Set Record Straight on Martian Salt Find

This view combines more than 400 images taken during the first several weeks after NASA's Phoenix Mars Lander arrived on an arctic plain on Mars. (Image credit: NASA/JPL-Caltech/UA/Texas A&M.)

Thechemical NASA's Phoenix Mars Lander found in a sample of Martian dirt, asannounced on Monday, may not be harmful to any potential life there and couldin fact be a boon to it, mission scientists said today.

"[Thisfinding] caught me by surprise," said Phoenix principal investigatorPeter Smith of the University of Arizona in a Tuesday teleconference withreporters.

Afterrumors spread across the Internet last weekend that Phoenix had foundintriguing findings that werebeing withheld from the public, mission scientists addressed the media toquash what Smith called the "speculation that has become rampant on the Web."

The Phoenix team announced Monday that one of Phoenix's instruments had detected perchlorate,a highly oxidizing substance.

Thoughoxidizers can be harmful to life, this isn't the case for perchlorate,scientists said. "It does not precludelife on Mars. In fact it is a potential energy source," said WilliamBoynton of the University of Arizona, who is a co-investigator on the Thermaland Evolved-Gas Analyzer (TEGA), which heats up samples of the Martian dirt andanalyzes the vapors they give off to determine their composition.

On Earth, perchloratesare found in Chile's highly arid Atacama Desert, which is often used as ananalog to the Martian surface. Scientists had originally thought no life couldsurvive in the Atacama, but later research found organics in nitrate depositsassociated with perchlorates. The same could hold true for Mars, the Phoenixresearch team said.

Perchloratesare also highly soluble salts and could help scientists better understand thehistory of water on Mars. The presence of water ice at Phoenix's landing site wasconfirmed in a TEGA analysis last week.

Theperchlorate signal was detected in Phoenix's Microscopy, Electrochemistry andConductivity Analyzer's (MECA) wetchemistry lab, which dilutes dirt samples in water brought from Earth anddetects any soluble salts they contain.

"Wehave substantial evidence that our soil contains perchlorates," Smithsaid.

Scientistsdecided to look for a chlorine signal in TEGA's next sample on Sunday. If oneshowed up, the evidence for perchlorates "would have been rock solid."?But the analysis showed no evidence of chlorine.

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Andrea Thompson is an associate editor at Scientific American, where she covers sustainability, energy and the environment. Prior to that, she was a senior writer covering climate science at Climate Central and a reporter and editor at Live Science, where she primarily covered Earth science and the environment. She holds a graduate degree in science health and environmental reporting from New York University, as well as a bachelor of science and and masters of science in atmospheric chemistry from the Georgia Institute of Technology.