by analysing the data sent back from the Ptolemy instrument on board the Rosetta probe, reported the journal Science. The instrument scanned the dust raised by the lander Philae. The data showed the presence of oxygen, carbon and hydrogen, the key elements for the formation of water and simple sugars. They have not discovered life itself, the researchers were careful to add, however, they do form the basis. Professor Ian Wright, coordinator of the research programme, said: "The compounds we have detected are undoubtedly the ones that contributed to the formation of life on Earth". (AGI)