According to scientific the current understanding earth formed about 4.54 billion years ago and till now the theory was that life evolved on earth about 3.7bn years ago. This was primarily based on the fact that the oldest reported micro-fossils found dated to 3.46bn and 3.7bn years ago. However recent discoveries in Canada have changed the calculus as they found evidence of microbes thriving near hydrothermal vents on Earth’s surface just 300m years after the planet formed, making them between 3.75bn and 4.28bn years old which makes this by far the oldest micro-fossils ever found.
If confirmed, it would suggest the conditions necessary for the emergence of life are relatively basic. “If life is relatively quick to emerge, given the right conditions, this increases the chance that life exists on other planets,” said Dominic Papineau, of University College London, who led the research. Five years ago, Papineau and colleagues announced they had found microfossils in iron-rich sedimentary rocks from the Nuvvuagittuq supracrustal belt in Quebec, Canada. The team suggested that these tiny filaments, knobs and tubes of an iron oxide called haematite could have been made by bacteria living around hydrothermal vents that used iron-based chemical reactions to obtain their energy.
Scientific dating of the rocks has suggested they are at least 3.75bn years old, and possibly as old as 4.28bn years, the age of the volcanic rocks they are embedded in. Before this, the oldest reported microfossils dated to 3.46bn and 3.7bn years ago, potentially making the Canadian specimens the oldest direct evidence of life on Earth. Now, further analysis of the rock has revealed a much larger and more complex structure — a stem with parallel branches on one side that is nearly a centimetre long — as well as hundreds of distorted spheres, or ellipsoids, alongside the tubes and filaments.
It is a fascinating find because it gives us an idea of how quickly life evolved on Earth which in turn enables us to search for it on other planets both in our own solar-system and the ones we have found around other stars (once we can get to them). Whether the life would have evolved into something akin to Humans or still be in the micro-organism stage is something up in the air. My feel is that we will find evidence for something in the middle of both extremes, but the longer we search the more the possibility of finding intelligent life improves.
Source: Microfossils may be evidence life began very quickly after Earth formed
– Suramya