- The Washington Times - Monday, January 8, 2007

ASSOCIATED PRESS

Two NASA space probes that visited Mars 30 years ago may have stumbled upon alien microbes on the Red Planet and inadvertently killed them, a scientist theorizes in a paper released yesterday.

The problem was the Viking space probes of 1976 and 1977 were looking for the wrong kind of life and didn’t recognize it, the researcher said in a paper presented at a meeting of the American Astronomical Society in Seattle.

This report, based on a more expansive view of where life can take root, may have NASA looking for a different type of life form when its next Mars spacecraft is launched later this year, one of the space agency’s top scientists said.

Last month, excited scientists reported that new photographs of Mars showed geologic changes that suggest water occasionally flows there — the most tantalizing sign that Mars is hospitable to life.

In the 1970s, the Viking mission found no signs of life. But it was looking for Earthlike life, in which salt water is the internal liquid of living cells. Given the cold and dry conditions of Mars, that life could have evolved on the Red Planet with the key internal fluid consisting of a mix of water and hydrogen peroxide, said Dirk Schulze-Makuch, author of the new research.

That’s because a water-hydrogen peroxide mix stays liquid at very low temperatures (minus 68 degrees Fahrenheit), doesn’t destroy cells when it freezes and can suck scarce water vapor out of the air.

The Viking experiments wouldn’t have noticed hydrogen peroxide-based alien life and, in fact, would have killed it by drowning and overheating the microbes, said Mr. Schulze-Makuch, a geology professor at Washington State University.

One Viking experiment seeking life on Mars poured water on soil. That essentially would have drowned life based on hydrogen peroxide, Mr. Schulze-Makuch said. A different experiment heated the soil to see whether something would happen, but that would have baked microbes, he said.

“The problem was that they didn’t have any clue about the environment on Mars at that time,” Mr. Schulze-Makuch said. “This kind of adaptation makes sense from a biochemical viewpoint.”

In recent years, scientists have found life on Earth in conditions that were once thought too harsh, such as an ultra-acidic river in Spain and ice-covered lakes in Antarctica.

Mr. Schulze-Makuch’s research coincides with work being completed by a National Research Council panel nicknamed the “weird life” committee. The group worries that scientists may be too Earth-centric when looking for extraterrestrial life. The problem for scientists is that “you only find what you’re looking for,” said Penn State University geosciences professor Katherine Freeman, a reviewer of the NRC work.

A NASA Mars mission called Phoenix is set for launch this summer, and one of the scientists involved said he is eager to test the new theory about life on Mars. However, scientists must come up with a way to do that using the mission’s existing scientific instruments, said NASA astrobiologist and Phoenix co-investigator Chris McKay. He said the Washington State scientist’s paper piqued his interest.

“Logical consistency is nice, but it’s not enough anymore,” Mr. McKay said.

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