NASA Mars Rover Finds Organic Matter in Ancient Lake Bed

NASA's veteran Curiosity rover has found complex organic matter buried and preserved in ancient sediments that formed a vast lake bed on Mars more than 3bn years ago. From a report: The discovery is the most compelling evidence yet that long before the planet became the parched world it is today, Martian lakes were a rich soup of carbon-based compounds that are necessary for life, at least as we know it. Researchers cannot tell how the organic material formed and so leave open the crucial question: are the compounds remnants of past organisms; the product of chemical reactions with rocks; or were they brought to Mars in comets or other falling debris that slammed into the surface? All look the same in the tests performed. But whatever the ultimate source of the material, if microbial life did find a foothold on Mars, the presence of organics meant it would not have gone hungry. "We know that on Earth microorganisms eat all sorts of organics. It's a valuable food source for them," said Jennifer Eigenbrode, a biogeochemist at NASA's Goddard Space Flight Center in Maryland. The Curiosity rover also discovered that methane on the red planet changes with the seasons. The Verge: Where the methane is coming from is still a mystery, but scientists have some ideas, including that microbes may be the source of the gas. Researchers at NASA and other US universities analyzed five years' worth of methane measurements Curiosity took at Gale Crater, where the rover landed in 2012. Curiosity detected background levels of methane of about 0.4 parts per billion, which is a tiny amount. (In comparison, Earth's atmosphere has about 1,800 parts per billion of methane.) Those levels of methane, however, were found to range from 0.2 to about 0.7 parts per billion, with concentrations peaking near the end of the summer in the northern hemisphere, according to a study published today in Science. This seasonal cycle repeated through time and could come from an underground reservoir of methane, the study says. Whether that reservoir is a sign that there is or was life on Mars, however, is impossible to say for now.