FRESH CLAIMS ON OLDEST EVIDENCE OF LIFE ON EARTH
For a long time, 3.7 billion year old graphite was always thought to be the oldest evidence of life on Earth.
This was until the University College London in the UK, led by Matthew Dodd, found microbes in Quebec, Canada, presumed to be almost 4.3 billion years old.
Researchers claim to have discovered what they say could be fossils of some of the earliest living organisms survived on Earth. Considering the Earth is thought to be around 4.5 billion years old, this marks an extraordinarily early discovery for the presence of life.
Video credits: University College London
The microbes were found on the shorelines of the north eastern Canadian Nuvvuagittuq Supracrustal Belt (NSB), hidden away on iron in between layers of quartz. Formerly a hydrothermal vent, it is believed that microbes were largely present in this area billions of years ago.
They are known as “microfossils” and aren’t even visible to the naked eye due to how thin they are.
“The microfossils we discovered are about 300 million years older than the previously thought oldest microfossils,” explains Dr Dominic Papineau, also from UCL. “These rocks have a minimum age of 3.77 billion years, but some scientists in the field consider them to be as old as 4.28 billion years,” he continues to say.
The researchers published their investigation in the Nature.
The findings can prove whether life on Earth was a completely accidental scenario from perfect conditions arising, or if the propagation of life is a frequent occurrence on planets within the habitable zone of their star.
DO THEY SUGGEST LIFE ON MARS TOO?
Perhaps the most interesting aspect of this discovery is that it gives evidence that these kinds of organisms could have also evolved on Mars.
“Early Mars and early Earth are very similar places, so we may expect to find life on both planets at this time,” explained Dodd, the lead author of the study which was co-funded by NASA. Mars was believed to be warm with oceans on its surface 3.77 billion years ago. It’s presumed that if Earth was capable at hosting life this long ago, so was Mars.
“So, if we have lifeforms originating and evolving on Earth at this time then we may very well have had life beginning on Mars.” Dodd explains.
Many of the robots sent to analyse Mars’s surface have not looked at the rocky areas that were potentially created by hydrothermal vents. This opens up a significant area of interest for future exploration missions.
Of course, much like any research done on rocks being claimed to be fossils, there is large amounts of doubt cast on the findings.
ANY SUCH CLAIM FOR THE EARLIEST LIFE ON EARTH ATTRACTS SCEPTICISM
Francis Westall from the French national centre for scientific research is an expert on ancient fossil bacteria and is one of the sceptical many debating the findings of Dodd’s study.
“What I am not saying is that there could not have been life at 3.8 billion years ago,” Westall said. “But in rocks that have been so altered, like these have been, I think that morphological traces are unlikely to remain.”
A lot of scepticism around these findings seem to be based around the shape and lifespan of the bacteria found. It seems unlikely that the fossils were 4.3 billion years old, with the contentiousness leading the real age to be believed to be around the specified lower limit of 3.8 billion years. This 0.5 billion year discrepancy makes all the difference.
“Preservation in the NSB of carbonaceous material and minerals in diagenetic rosettes and granules that formed from the oxidation of biomass, together with the presence of tubes similar in mineralogy and morphology to those in younger jaspers interpreted as microfossils, reveal that life established a habitat near submarine-hydrothermal vents before 3,770 [million years] ago and possibly as early as 4,280 [million years] ago.” – An excerpt from the article produced by Dodd and Papineau.