Have Scientists Just Found the Earliest Evidence of Life On Earth?

Thursday, 22 October 2015 - 8:47PM
Thursday, 22 October 2015 - 8:47PM
Geochemist Elizabeth Bell and her colleagues recently published a study in the journal 'Proceedings of the National Academy of Sciences' that presents evidence that the team may have found the earliest evidence of life on planet earth.

The currently accepted date concerning the beginning of life on earth goes back to 3.8 billion years ago. However, if the findings of Bell and her team are accurate, that date could potentially get pushed back an additional 300 million years.

The major find of the study was a bit of graphite that dated back to 4.1 billion years ago. The graphite has an isotopic signature that's very similar to the isotopic signature of organic matter. This means that it's quite possible that the graphite they found was possibly once organic as well, and that it was later pressurized into the graphite they found.

This was quite a rare find, as usually rocks don't survive for more than 4 billion years due to cycles of erosion and deposition. However, they found this graphite in a type of crystal called a zircon, which can survive much longer.

Though this is quite exciting, it must be noted that there are other explanations for the existence of such materials so early on in the earth's history. Bell and her team freely acknowledge this, but favor the idea that what they've found is truly the earliest evidence of life on earth. Interestingly enough, their theory could end up being proven if life is ever found on Mars. Apparently 4 billion year old rocks still exist on the red planet's surface, and so if life can be found dating back to these early periods on Mars, it becomes easier to believe life could have existed in these same periods on earth.

Of course, there's other tests that could verify the theory as well. It all just goes to show how little mankind has learned about the world around us in comparison to how much there is still left to learn.
Science News

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