Washington, Oct 17 : A new analysis of samples from a classic 'origin-of-life' experiment by NASA has suggested that lightning and gases from volcanic eruptions could have given rise to the first life on Earth.
"Historically, you don't get many experiments that might be more famous than these; they re-defined our thoughts on the origin of life and showed unequivocally that the fundamental building blocks of life could be derived from natural processes," said lead author Adam Johnson, a graduate student with the NASA Astrobiology Institute team at Indiana University, US.
The team, which also comprised of Jeffrey Bada, the co-author of the study paper, wanted to see if modern equipment could discover chemicals that could not be detected with the techniques of the 1950s.
They analyzed the samples collected by Professor Stanley Miller (University of Chicago) from 1953 to 1954, and turned to Daniel Glavin and Jason Dworkin of NASA's Goddard Space Flight Center, who helped the analysis with state-of-the-art instruments in their Goddard Astrobiology Analytical lab.
"We discovered 22 amino acids, 10 of which have never been found in any other experiment like this," said Glavin.
This is significant because thinking on the composition of Earth's early atmosphere has changed.
Instead of being heavily laden with hydrogen, methane, and ammonia, many scientists now believe Earth's ancient atmosphere was mostly carbon dioxide, carbon monoxide, and nitrogen.
However, in addition to water and carbon dioxide, volcanic eruptions also release hydrogen and methane gases.
Volcanic clouds are also filled with lightning, since collisions between volcanic ash and ice particles generate electric charge.
Since the young Earth was still hot from its formation, volcanoes were probably quite common then.
The organic precursors for life could have been produced locally in tidal pools around volcanic islands, even if hydrogen, methane, and ammonia were scarce in the global atmosphere.
As the tidal pools evaporated, they would concentrate the amino acids and other molecules, making it more likely that right sequence of chemical reactions to start life could occur.
"In fact, volcanic eruptions could assist the origin of life in another way as well - they produce carbonyl sulfide gas, which helps link amino acids into chains called peptides," said Glavin.
According to Carl Pilcher, director of the NASA Astrobiology Institute headquartered at NASA Ames Research Center, "This research is both a link to the experimental foundations of astrobiology as well as an exciting result leading toward greater understanding of how life might have arisen on Earth."