More building blocks of life found on Mars

A NASA robot has detected more building blocks for life on Mars -- the most complex organic matter yet -- from 3.5 billion-year-old rocks on the surface of the Red Planet, scientists said Thursday.The unmanned Curiosity rover has also found increasing evidence for seasonal variations of methane on Mars, indicating the source of the gas is likely the planet itself, or possibly its subsurface water.While not direct evidence of life, the compounds drilled from Mars' Gale Crater are the most diverse