Living organisms may have existed on Earth as long as 4.1bn years ago – 300m years earlier than was previously thought, new research has shown.
If confirmed, the discovery means life emerged a remarkably short time after the Earth was formed from a primordial disc of dust and gas surrounding the sun 4.6bn years ago.
Researchers discovered the evidence in specks of graphite trapped within immensely old zircon crystals from Jack Hills, Western Australia.
Atoms in the graphite, a crystalline form of carbon, bore the hallmark of biological origin. They were enriched with 12C, a "light" carbon isotope, or atomic strain, normally associated with living things.
It suggests that a terrestrial biosphere had emerged on Earth as early as 4.1bn years ago, said the scientists writing in the journal Proceedings of the National Academy of Sciences.
(Score: 4, Informative) by takyon on Friday October 23 2015, @09:28PM
A broad definition of life could include viruses and proto-RNA. Molecules or collections of molecules that can make more of themselves. That at least requires some stars to go supernova and produce heavy elements. So there is a lower bound on when "life" can begin.
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