Mars Has Methane—But Does It Have 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.

“While previous observations, including that of Curiosity, have been debated, this first independent confirmation of a methane spike increases confidence in the detections,” said study lead author Marco Giuranna, of the Istituto Nazionale di Astrofisica in Rome.

And that’s not all. Giuranna and his team also traced the likely source of the June 2013 plume to a geologically complex region about 310 miles (500 kilometers) east of Gale Crater.

The researchers used data gathered by Mars Express’ Planetary Fourier Spectrometer instrument (PFS), which also sniffed out traces of Red Planet methane back in 2004. (The spacecraft has been orbiting Mars since December 2003.)

Giuranna, the PFS principal investigator, had prepared for synergy with the Curiosity team. Soon after the rover’s August 2012 touchdown inside Gale, he decided to monitor the air above the crater over the long term, Giuranna said.