Back in 2016, a team of Australian researchers announced the discovery of 3.7-billion-year-old fossils in Greenland. Thought to be stromatolites, they represent a relatively complex step along the evolutionary chain. According to science writer Ed Yong, this suggests that life in a simpler form must have emerged long before.
Interestingly, their age wasn’t the only significant thing that scientists observed about the pieces of graphite. Apparently, the study also revealed evidence that the organisms from which it had formed may have been autotrophic, or capable of producing their own food from their environment.