Comet landing: Organic molecules detected by Philae
19 November 2014 Last updated at 03:05 GMT
The Philae lander has detected organic molecules on the surface of its comet, scientists have confirmed.
Carbon-containing "organics" are the basis of life on Earth and may give clues to chemical ingredients delivered to our planet early in its history.
Professor David Southwood was at the European Space Agency when they launched the Rosetta mission.
He told the BBC: "We really are going back to the origin of our solar system."