Geologists discover possible evidence of 3.7-billion-year-old life forms

Life on Earth might actually be 220 million years older than we originally thought. Geologists working in Greenland have discovered what they believe are signs of microbes in a 3.7-billion-year-old rock, which, if confirmed, would be the oldest known evidence of life ever discovered on our planet.

Geologists believe they have found stromatolites in the ancient rock. The structures "look a bit like geological cauliflowers" and "form when microbes trap sediment and build up layer after dome-shaped layer," Nature reports. But because the rocks are so old, it is extremely tricky for researchers to verify if the layers are indeed fossilized stromatolites.

"At most, these structures should be classified as pseudostromatolites," said consulting paleontologist Kathleen Grey. As Nature notes, structures that look like stromatolites can form for entirely non-biological reasons, like minerals on the sea floor causing marks. "Sadly, I don't feel the evidence is convincing for such an important claim," Grey added.

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Still, even if the rocks don't end up indicating primordial life, they could actually help with the understanding of another frontier entirely: outer space. "It's incredible that anything can be found in these rocks that are barely a ghost of what they were before. That's why it's worthy of attention," said Abigail Allwood, an astrobiologist for NASA.

The rocks could help future scientists grapple with what constitutes as evidence of life in upcoming space explorations, such as the NASA mission to Mars in 2020.