Methane on Mars; Sign of Life?

We may be one step closer to cracking the Mars methane mystery.

NASA's Curiosity rover mission recently determined that background levels of methane in Mars' atmosphere cycle seasonally, peaking in the northern summer. The six-wheeled robot has also detected two surges to date of the gas inside the Red Planet's 96-mile-wide (154 kilometers) Gale Crater — once in June 2013, and then again in late 2013 through early 2014.

These finds have intrigued astrobiologists, because methane is a possible biosignature. Though the gas can be produced by a variety of geological processes, the vast majority of methane in Earth's air is pumped out by microbes and other living creatures.

Some answers may soon be on the horizon, because that June 2013 detection has just been firmed up. Europe's Mars Express orbiter noted the spike as well from that spacecraft's perch high above the Red Planet, a new study reports.