NASA, ESA, M.A. Garlick (space-art.co.uk), University of Warwick, and University of Cambridge.
Scientists have created the chemical building blocks of DNA in a dish, using a laser to simulate asteroid and comet impacts on the early Earth.
Dr Chris Smith from the Naked Scientists told This Way Up's Simon Morton that about 4 billion years ago, the Earth experienced a 150 million year battering called the Late Heavy Bombardment. Up to one billion tonnes of material per year crashed into the planet from space at speeds of up to 20 kilometres per second.
A Czech Academy of Sciences researcher Martin Ferus and his colleagues has recreated these intense conditions using blasts from a powerful iodine laser.
This produced a flurry of chemical reactions as molecules were ripped apart and then recombined in new ways. The result was a mixture that included three of the four genetic letters found in DNA and all four of the genetic letters found in its chemically simpler cousin, RNA. This is thought to be the first form of genetic material to have existed on Earth.
Despite some criticism of the work, Dr Smith says it could help to solve one of science's great unsolved mysteries: did the crucial chemicals that kick-started life on Earth arrive from space, or were they generated here?
"This lends enormous credibility to the idea that you could have formed the molecules of life early on...because the conditions, the high temperatures of 4000 degrees plus when these comets would have hit the surface of the earth, were enough to drive these sorts of chemical reactions and make these very complicated chemicals."
