Curiosity's search for life has turned up some disappointing news. According to test results published today in Science, the search for methane-producing microbes on Mars has turned up empty.

The odds for life on Mars are looking slim

The story starts with a 2003 report that detected plumes of methane on Mars, giving many hope of finding microbial life as a result. Unfortunately, the new study reports that after years of searching, Curiosity's spectrometer has yet to turn up a measurable quantity of methane in the atmosphere. Today's report doesn't mean there's no methane at all on Mars, but without enough to measure, the odds of finding methane-producing life on Mars are looking slim. There's also the chance that Mars is hosting a form of microbe that doesn't produce methane, which are extremely rare but have been discovered on Earth before.

Update: As the Curiosity team stated in the report, "there are micro-organisms that don't produce methane, so we're not totally giving up on the possibility of Martians just yet." They've since reiterated this point on Twitter.