She does admit, however, that the finding isn’t enough to glean too much about early Earth environments during the Hadean time period (from the beginning of Earth to about 4 billion years ago) or about how life initially began.
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“Twenty years ago, this would have been heretical; finding evidence of life 3.8 billion years ago was shocking”, said Mark Harrison, co-author of the research and a professor of geochemistry at UCLA.
Harrison said, “Life on Earth may have started nearly instantaneously”. The zircon containing the specks of graphite is considered the oldest-known rock fragment dating back almost 4.1 billion years. Originating in the molten rock of the region, zircons are durable minerals that often preserve pieces of material surrounding them as they formed.
In a 2009 research, University of Colorado at Boulder scientists said they’ve found evidence to confirm that the late heavy bombardment would have melted only a fraction of Earth’s crust, and that life could well have survived in subsurface habitats, and insulated from the destruction.
The new research suggests that life existed prior to the massive bombardment of the inner solar system that formed the moon’s large craters 3.9 billion years ago. “With the right ingredients, life seems to form very quickly”, Harrison noted. They analyzed a few of the zircons with Raman spectroscopy, a spectroscopy technique showing molecular and chemical structure of microorganisms in 3-D.
What they found were that the atoms found within the graphite were made from 12C, a carbon strain that is normally connected to living organisms.
The study is now accessible via the Pnas.org website, with the title “Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon”.
The researchers found graphite in just one of the 79 zircons.
If confirmed, the discovery means that life emerged a remarkably short time after the Earth was formed from a prim-ordial disc of dust and gas surrounding the sun 4.6 billion years ago. The carbon contained in the zircon also has a characteristic signature – a specific ratio of carbon-12 to carbon-13 – that indicates the presence of photosynthetic life. The graphite encapsulated in the zircon was the basis of the research.
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Bell concisely summed up the significance of the findings, stating simple that, in light of the discovery, “We need to think differently about the early Earth”. Harrison, Boehnke and study lead author Elizabeth Bell, also at UCLA, detailed their findings online October. 19 in the journal Proceedings of the National Academy of Sciences.
