Researchers say they've found fossilized bacteria that may date back to shortly after the formation of the Earth (geologically speaking, anyway), the New York Times reports. They published their findings Wednesday in Nature. The rocks were collected in 2008 from the Nuvvuagittuq geological formation in Canada. The rocks are estimated to have formed near a hydrothermal vent on the seafloor between 3.77 billion and 4.22 billion years ago. They contain tiny filaments and tubes, some connected by knobs, that resemble younger bacteria fossils created near hydrothermal vents. They also contain a level of carbon indicative of a living organism.
If the fossils are what researchers say they are—and not everyone is convinced they are—they would push the date of earliest known life back billions of years. Currently the oldest fossilized bacteria widely accepted as legitimate are 3.5 billion years old and come from Australia, Ars Technica reports. And if these Canadian fossils are closer to 4.22 billion years old, it means the bacteria would have been alive just 340 million years after the formation of the Earth. Still, every new claim of finding the world's oldest fossilized life is met with skepticism, and this discovery is no different. One expert calls the rocks "dubiofossils," fossil-like but not clearly evidence of an organism. In response, researchers argue there's too much evidence in favor of their conclusion to ignore. (This dinosaur fossil is one of the "saddest" ever found.)