Fossil find
Discovery shows Earth dates back 4.2 billion years
It’s life, but not as we know it.
The oldest fossil ever discovered on Earth shows that organisms were thriving 4.2 billion years ago, hundreds of millions of years earlier than previously thought.
The microscopic bacteria, which were smaller than the width of a human hair, were found in rock formations in Quebec, Canada, but would have lived in hot vents in the 60C oceans which covered the early planet.
The discovery is the strongest evidence yet that similar organisms could also have evolved on Mars, which at the time still had oceans and an atmosphere, and was being bombarded by comets which probably brought the building blocks of life to Earth.
The team at University College London who made the finding believe that looking for similar fossils on the Red Planet is the best chance of finding evidence of alien life.
“Early Mars and early Earth are very similar places, so we may expect to find life on both planets at this time,” said doctoral student Matthew Dodd, the lead author of the study which was co-funded by Nasa.
“We know that life managed to get a foothold and evolve rapidly on Earth. So if we have life evolving in hydrothermal vent systems maybe even 4.2 billion years ago when both planets had liquid water on their surface, then we would expect both planets to develop early life.
“If we do future sample returns from Mars and look at similarly old rocks and we don’t find evidence of life then this certainly may point to the fact that Earth might have been a very special exception, and life may just have arisen on Earth.”
Prior to this discovery, the oldest microfossils reported were found in Western Australia and dated at 3.4 billion years ago.