Scientists have discovered what they say could be fossils of some of the earliest living organisms on Earth.
They are represented by tiny filaments, knobs and tubes in Canadian rocks dated to be up to 4.28 billion years old.
That is a time not long after the planet's formation and hundreds of millions of years before what is currently accepted as evidence for the most ancient life yet found on Earth.
The researchers report their investigation in the journal Nature.
As with all such claims about ancient life, the study is contentious. But the team believes it can answer any doubts.
Μάλλον βρήκαμε αποτυπώματα μικροοργανισμών που έζησαν μεταξύ 3,77 και 4,28 δισ. ετη πριν από σήμερα (μάλλον βέβαια πιο κοντά στο 3,77, παρά στο 4,28, αλλά και πάλι παλιότερα από τα μέχρι πρότινος αρχαιότερα απολιθώματα). Για να έχουμε μια εικόνα για πόσο παλιά μιλάμε:
Βέβαια, κάτι τόσο αρχαίο δεν είναι 100% σίγουρο ότι είναι όντως απολίθωμα, αλλά αν αποδειχθεί πέραν αμφιβολίας, μιλάμε για πολύ σημαντική ανακάλυψη.
Part of the interest in ancient life is in the implication it has for organisms elsewhere in the Solar System.
"These (NTB) organisms come from a time when we believe Mars had liquid water on its surface and a similar atmosphere to Earth at that time," said Mr Dodd.
"So, if we have lifeforms originating and evolving on Earth at this time then we may very well have had life beginning on Mars."
If that is the case then, according to Dr Papineau, recent Nasa rover missions to the Martian surface may have been looking for signs of life in the wrong places.
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The suggestion that life had already arisen "just" a few hundred million years after the Earth had formed is intriguing in light of debates about whether life on Earth was a rare accident or whether biology is a common outcome given the right conditions.
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