WASHINGTON – Two NASA space probes that visited Mars 30 years ago might have stumbled upon alien microbes and inadvertently killed them, a scientist theorizes in a paper released Sunday.
The problem was the Viking space probes of 1976-77 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.
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 ’70s, 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 Dirk Schulze-Makuch, author of the new research.
That’s because a water-hydrogen peroxide mix stays liquid at very low temperatures (-68 degrees Fahrenheit), doesn’t destroy cells when it freezes, and can suck scarce water vapor out of the air.
The Viking experiments of the ’70s wouldn’t have noticed alien hydrogen peroxide-based life and, in fact, would have killed it by drowning and overheating the microbes, said Schulze-Makuch, a geology professor at Washington State University.
One Viking experiment seeking life on Mars poured water on soil, and would have essentially drowned hydrogen peroxide-based life, Schulze-Makuch said. A different experiment heated the soil to see if something would happen, but that would have baked Martian microbes, he said.
“The problem was that they didn’t have any clue about the environment on Mars at that time,” Schulze-Makuch said.
Schulze-Makuch acknowledges he can’t prove that Martian microbes exist, but given the Martian environment and how evolution works, “it makes sense.”