Ever since humans first looked up at the stars with an awareness that those far off lights were physical bodies, bobbing like islands in the vast sea of space, we’ve wondered if we were not alone. Today, we have more tools at our disposal to enable us to explore the heavens than ever before, but life outside our delicate blue pebble remains elusive. Evidence still crops up from time to time, however.

The most recent evidence to suggest life may exist in our own celestial backyard has found its way to scientific discussion, and despite the lofty language one can ascribe to this endeavor, the science behind it is really pretty simple: it’s farts. Okay, so it’s the gas that you can usually find in farts – methane.

Methane has been detected on Mars a number of times in the past, but most detection remained the subject of debate. Now, the European Space Agency’s (ESA) Mars Express Orbiter has corroborated those findings, settling the debate once and for all, and spurring a whole series of new ones.

Within astrobiologist circles, methane is considered to be a “possible biosignature.” What that means is, the presence of methane in an alien environment could be indicative of life as we know it. While there are geological processes that can produce methane, the vast majority of naturally occurring methane found on Earth is produced by living creatures.