A REPEAT of a classic experiment into the origins of life on Earth shows it was more successful than anyone realised, and offers clues as to how life could arise on other planets.
In the 1950s, Stanley Miller of the University of Chicago heated a mixture of water and gases thought to have been present in primordial Earth鈥檚 atmosphere, and zapped it with electricity to mimic the effect of lightning. This created five amino acids 鈥� the building blocks of proteins. Now Jeffrey Bada of the Scripps Institution of Oceanography in San Diego, California, and his team have repeated the tests using the original samples. They also reran an unpublished version of the experiment in which the amount of steam was increased to mimic conditions near a volcanic eruption.
Bada found that the volcanic version generated 22 amino acids 鈥� double the number Miller identified with the techniques of the time. Many of these have 鈥渘ever been detected in a simulated early Earth experiment鈥�, he says (Science, ). One reason for this might be that the extra steam pushes newly formed amino acids out of the reaction zone, so they cannot react further.
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Such volcanic conditions could have once existed on Mars, says Bada, who is developing instruments to detect amino acids frozen beneath the planet鈥檚 surface.
