Geochemists have found evidence that life on Earth could have started 300 million years earlier than previously thought. Researchers believe that life may have started 4.1 billion years ago, which means it is older than the asteroid bombardments that scarred the Moon — making it nearly as old as the 4.54 billion-year-old planet itself.
Mark Harrison, the co-author and a professor of geochemistry at the University of California, Los Angeles (UCLA), said in a statement: “Twenty years ago, this would have been heretical; finding evidence of life 3.8 billion years ago was shocking.”
‘Life on Earth may have started almost instantaneously, with the right ingredients life forms very quickly.’
The team of geologists from UCLA, suggests that life had existed before the massive bombardment of the inner solar system, which had formed the Moon’s large craters around 3.9 billion years ago. Some scientists have argued that while this was going on, all life on Earth would have ceased to exist.
Patrick Boehnke, a co-author of the research and a graduate student said: “If all life on Earth died during this bombardment, which some scientists have argued, then life must have restarted quickly.”
It has been long believed by scientists that Earth was dry and desolate during that time period. But Harrison’s research, which also includes a study that he had co-authored in 2008, is proving otherwise.
‘The early Earth certainly wasn’t a hellish, dry, boiling planet; we see absolutely no evidence for that.’
“The planet was probably much more like it is today than previously thought.”
The researchers have studied over 10,000 zircons in Western Australia; zircons form from molten rocks or magmas. Zircons are heavy, durable minerals and are related to the synthetic cubic zirconium, which is used to imitate diamonds.
The authors of the new study that has been published in the journal Proceedings of the National Academy of Sciences, explain that zircons are like time capsules because they “capture and preserve their immediate environment.”
There were 656 zircons that were identified as containing dark specks, that could contain carbon, but only 79 were chosen to be analyzed using Raman spectroscopy. This technique shows the molecular and chemical structure of ancient micro-organisms in three dimensions.
Zircon contained carbon, which essential for life
Lead researcher Elizabeth Bell, along with Boehnke, had pioneered chemical and mineralogical tests, which determine the condition of ancient zircons. Researchers were looking for any signs of carbon, which is the key component of any life. They were rewarded for their work when 1 out of the 79 zircons contained graphite, pure carbon, in not only one location, but two.
“The first time that the graphite ever got exposed in the last 4.1 billion years is when Beth Ann and Patrick made the measurements this year,” Harrison said in the statement.
When asked just how confident the researchers were that the zircon represented 4.1 billion-year-old graphite, Harrison said: “Very confident.”
“There is no better case of a primary inclusion in a mineral ever documented, and nobody has offered a plausible alternative explanation for graphite of non-biological origin into a zircon.”
Based on its ratio of uranium, this led researchers to discover it is 4.1 billion years old. The graphite that is contained within the zircon is older. However, it is unknown how much older the graphite is.
Research seems to suggest that life in the universe could be abundant, Harrison said. It also suggests that basic life had formed quickly, but is very likely to have taken millions of years for the very basic life to evolve the ability to photosynthesize.
“We need to think differently about the early Earth,” Bell said.
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