New fossil evidence from rocks found in Canada suggests life on Earth began between 3.75 to 4.2 billion years ago, a new study says.
If the research published in Science Advances is proven correct, the microbial fossils would be the oldest life ever found on the planet, and could indicate that life began a mere 300 million years after the Earth first formed some 4.5 billion years ago.
Scientists at University College London found minuscule structures inside the rocks they believe could only have been made by microbes, living billions of years ago near hydrothermal vents in the oceans.
Previously, the earliest confirmed microfossils were around 3.5-3.7 billion years old.
The fossils in the rocks were first described in a 2017 study by lead researcher Dominic Papineau, associate professor in geochemistry and astrobiology at UCL. However, some doubted that the structures were biological in origin, leading to more years of work by the team to ascertain how they were created.
The team described a tree-like structure about a centimeter across. The scientists said the characteristics of the structure make it highly unlikely it was created through chemical processes alone. It is also similar to those created today by some bacteria.
“These microfossils might actually exist on other ancient planetary surfaces because if the origin of life takes such a short time to develop, and you have this level of complexity, then that brings up a lot of new philosophical questions about the probability that life might have arisen and left these kinds of imprints behind,” Papineau told Vice News. “It creates a lot of new opportunities to push back the clock for the origin of life and to search specifically for these kinds of things on other planets.”