WASHINGTON (AP) -- Two NASA space probes that visited Mars 30 years ago may have found alien microbes on the Red Planet and inadvertently killed them, a scientist is theorizing.
The Viking space probes of 1976-77 were looking for the wrong kind of life, so they didn't recognize it, a geology professor at Washington State University said.
Dirk Schulze-Makuch presented his theory in a paper delivered at a meeting of the American Astronomical Society in Seattle, Washington.
The paper was released Sunday.
Based on a more expansive view of where life can take root, the paper's findings may prompt NASA to look for a different type of Martian life when its next spacecraft to visit Mars is launched later this year, one of the space agency's top scientists said.
Last month, scientists excitedly 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 Earth-like life, in which salt water is the internal liquid of living cells.
Given the cold dry conditions of Mars, life could have evolved on Mars with the key internal fluid consisting of a mix of water and hydrogen peroxide, said Schulze-Makuch.
That's because a water-hydrogen peroxide mix stays liquid at very low temperatures, or -68 degrees Fahrenheit, and doesn't destroy cells when it freezes. It can suck water vapor out of the air.
The Viking experiments of the 1970s wouldn't have noticed hydrogen peroxide-based life and, in fact, would have killed it by drowning and overheating the microbes, said Schulze-Makuch.
One Viking experiment seeking life on Mars poured water on soil. That would have essentially drowned hydrogen peroxide-based life, he said. And different experiment heated the soil to see if something would happen which would have baked Martian microbes.
http://www.cnn.com/2007/TECH/01/07/mars.life.ap/index.html
The Viking space probes of 1976-77 were looking for the wrong kind of life, so they didn't recognize it, a geology professor at Washington State University said.
Dirk Schulze-Makuch presented his theory in a paper delivered at a meeting of the American Astronomical Society in Seattle, Washington.
The paper was released Sunday.
Based on a more expansive view of where life can take root, the paper's findings may prompt NASA to look for a different type of Martian life when its next spacecraft to visit Mars is launched later this year, one of the space agency's top scientists said.
Last month, scientists excitedly 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 Earth-like life, in which salt water is the internal liquid of living cells.
Given the cold dry conditions of Mars, life could have evolved on Mars with the key internal fluid consisting of a mix of water and hydrogen peroxide, said Schulze-Makuch.
That's because a water-hydrogen peroxide mix stays liquid at very low temperatures, or -68 degrees Fahrenheit, and doesn't destroy cells when it freezes. It can suck water vapor out of the air.
The Viking experiments of the 1970s wouldn't have noticed hydrogen peroxide-based life and, in fact, would have killed it by drowning and overheating the microbes, said Schulze-Makuch.
One Viking experiment seeking life on Mars poured water on soil. That would have essentially drowned hydrogen peroxide-based life, he said. And different experiment heated the soil to see if something would happen which would have baked Martian microbes.
http://www.cnn.com/2007/TECH/01/07/mars.life.ap/index.html