NASA's Curiosity rover has discovered previously unknown organic molecules, ammonia and benzoic acid, on Mars that could be possible indicators of ancient life. The findings stem from a new technique used by the American space agency in 2017 when the rover's drill stopped working, but the team re-routed Curiosity to place dirt samples into cups pre-filled with a chemical mixture instead of the typical empty containers. The molecules are not biosignatures, evidence of past or present life, but according Maëva Millan, a postdoctoral fellow at NASA's Goddard Spaceflight Center, they are good indicators of the presence of biosignatures.... The dirt...