Curiosity draws a blank on Mars methane Since August last year NASA's Curiosity rover has been probing Mars to try and confirm scientific theories the Red Planet showed signs of life. Over the past decade Earth-based and orbital telescopes had spotted plumes of vapour in the Martian atmosphere that were identified as methane, a sure sign of microbial activity. With Mars's atmosphere thought capable of containing methane for a 200-year period, scientists had expected Curiosity to find lots of it. But it has not, and now experts say all their theories about life on Mars have been thrown into doubt, and their atmospheric models will have to be revised. Curiosity's search continues, and while the atmospheric tests are disappointing, there are hopes geological samples may come up trumps. More about: Mars, NASA, Space exploration, Space mission