Were Mars microbes killed by NASA?

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 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.

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

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, that 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.

Who knows if they are not not revealing themselves because they're scared of us Earthlings now?