If there are any little green men on Mars, or at least little green microbes, the Mars rover Curiosity can't find any trace of them. NASA reported today that a series of tests turned up no signs of telltale methane, reports Space.com. The results are especially disappointing given that researchers a few years back thought they had detected plumes of methane gas on the planet, notes National Geographic. The results don't conclusively rule out the possibility of microbial life, but they don't bode well, either.
"It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what's really important," says lead author Chris Webster of NASA's Jet Propulsion Laboratory. "We measured repeatedly from Martian spring to late summer, but with no detection of methane." (Read more Mars stories.)