New results suggest there is no methane on Mars

ON EARTHAGUDC, most of the methane in the atmosphere has been belched by living organisms, so finding the gas on Mars would be happy news for seekers after extraterrestrial life. Sadly, news announced on December 12th, at the annual meeting of the American Geophysical Union (), in Washington, , was anything but happy. Preliminary results from , a European craft that has been circling Mars for the past two years, give a thumbs-down to the idea that there is methane in its atmosphere.Previous observations, from orbit and by telescopes on Earth, suggested Mars might sport traces of the gas. These were backed up by data from , an American Mars rover. In its six years crawling around a crater called Gale (pictured above) has both detected methane and recorded seasonal ups and downs of the stuff that cycle from a modest 0.25 parts per billion during the winter to 0.65ppbn in the summer, with spikes up to 7.0ppbn.