At 4.4 billion years old, a tiny zircon crystal about twice the size of a human hair is the oldest known piece of the Earth’s crust.
Found on a sheep ranch in western Australia over a dozen years ago, the findings about the speck suggest new possibilities about how early life existed on the planet.
A light-optical microscope image of a zircon. Photo by Wikimedia user Chd
Scientists used two different dating techniques to confirm the gem’s age, and published their findings Sunday in the journal Nature Geoscience. Given the Earth formed roughly 4.5 billion years ago, researchers believe that this finding suggests that the Earth’s crust formed relatively soon after the formation of the planet.
With the idea that the Earth went from a molten rock to possibly habitable within the course of 100 million years, scientists on the project believe that the conditions on young Earth may not have been as harsh as previously predicted. With calmer conditions, life on Earth may have been possible earlier than previously thought.
John Valley, a geoscience professor at the University of Wisconsin and lead researcher on the crystal, suggests that Earth was capable of sustaining oceans, and even microbial life, around 4.3 billion years ago.
“We have no evidence that life existed then. We have no evidence that it didn’t,” Valley told Reuters. “But there is no reason why life could not have existed on Earth 4.3 billion years ago.”
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