NASA's Curiosity rover made a compelling find on Mars' irradiated surface. The car-sized robot's molecule-sleuthing instrument, called Sample Analysis at Mars, or SAM, identified the longest-ever-found organic compounds on Mars.

While Curiosity mission scientists have previously identified small, simple organic molecules on the red planet, the discovery of the larger molecular compounds offers the first evidence that organic chemistry on Mars evolved toward a complexity necessary to become an origin for life on the planet, the Goddard update notes.