# Earliest evidence of life discovered - 4.2 billion years ago?



## Brian G Turner (Mar 1, 2017)

The BBC reports on a contentious claim that forms in rocks - possible as old as 4.2 billion years - are actually fossils. And therefore the oldest evidence of life on earth:

Earliest evidence of life on Earth 'found' - BBC News


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## Dave (Mar 1, 2017)

Ultimately, this feeds into the question of what is "life" because I think (as was shown in some recent experiments last year) we can create chemical reactions that behave just like life, but which we do not consider to be life. Those red rocks shown in the picture were probably deposited when the Earth's Oxygen atmosphere first began to form, and free Iron that had existed in the previously reducing chemical environment began to be oxidised. So, that does tie it to the first appearance of life. On the other hand, those kinds of long iron rich structures were also found in Martian meteorites, and at first declared to be fossils, and then later backtracked and declared to be simply chemical structures. I believe that is why the claim is always going to be contentious and I don't think we know enough yet to say for sure.


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## BAYLOR (Mar 1, 2017)

Life 800 million years after the Earth formed? That soon afterwards  The Earths crust would have likely have been hot and  unstable and more so  with the moon  being in much closer proximity to the earth . And isn't 4.2 billion years too early for water to have been on the Earths surface? Not idea conditions for any kind of life.


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## Dave (Mar 1, 2017)

BAYLOR said:


> Life 800 million years after the Earth formed? That soon afterwards  The Earths crust would have likely have been hot and  unstable and more so  with the moon  being in much closer proximity to the earth . And isn't 4.2 billion years too early for water to have been on the Earths surface?





> The fossil structures were encased in quartz layers in the so-called Nuvvuagittuq Supracrustal Belt (NSB).
> The NSB is a chunk of ancient ocean floor. It contains some of the oldest volcanic and sedimentary rocks known to science.


I would think the answer to that lies in the terms "ancient ocean floor" and "sedimentary rocks"?


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## Alexa (Mar 2, 2017)

> In terms of the search for life on other planets, O'Neil says it might be hard to analyze a rock sample from the recently-discovered planets orbiting TRAPPIST-1, 39 light-years away. However, he says it should help narrow down the search for life on Mars to regions where water once covered the planet's surface.
> 
> "Instead of searching the whole planet of Mars, you can target these specific areas," he said, adding that Earth and Mars were "probably very similar" 4.3 billion years ago.
> 
> "I wouldn't be surprised to have these type of environments preserved on Mars as well," he said. "This is where life started on Earth… so let's look for them on Mars."



I like BBC's article more than ours. Especially the history of life on Earth. We are so young and still have a lot to learn, but I'm sure one day we will find life on other planets. Mars is closer for the moment.

'Oldest record of life on Earth' found in Quebec


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## Stephen Palmer (Mar 3, 2017)

Highly controversial!


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