The search for biology on neighbor planet Mars won’t play out like a Hollywood movie starring little green men. Rather, many scientists agree if there was life on the Red Planet, it probably will present itself as fossilized bacteria. To find it, astrobiologists likely will need to decode the chemical analysis of rock samples performed by a rover (like the one NASA plans to send to Mars in 2020). Only then might humankind know conclusively that life exists beyond Earth.