(Note: photo above is not the fossil in this article)
Scientists of all disciplines generally accept that the Earth is about 4.5 billion years old. Paleontologists are dependent upon fossils to determine when the first life appeared on Earth, so fossilized microorganisms found in Australian Apex chert rocks that date back 3.465 billion years are generally considered to be the first confirmed life forms. That may change significantly as experts analyze a rock found in Quebec, Canada, with tiny fossilized filaments and other evidence suggesting they were made by bacteria that lived between 3.75 and 4.28 billion years ago. If this is confirmed, it pushes the birth of life on Earth back 300 million years to very near the birth of the planet itself. Does this qualify as a “This changes everything!” moment?
“This means life could have begun as little as 300 million years after Earth formed. In geological terms, this is quick – about one spin of the Sun around the galaxy.”
Dr Dominic Papineau, an associate professor in geochemistry and astrobiology at University College London and lead author of a report on the discovery published in the journal Science Advances, sounds pretty excited about the fossil in a press release. Of course, that could be because he found it – he collected it, along with others, from a former seabed in Quebec’s Nuvvuagittuq Supracrustal Belt (NSB) in 2008. The canhces of finding ancient fossils are excellent here – the NSB was once near a system of hydrothermal vents heated by magma. Besides panspermia and biblical creationism, hydrothhemal vests are thought to be places where heat and chemicals could react to form life that might live on metals and elements on the sea floor.
“One thing that I think is amazing is the sheer size of the tectonic branching structure, which is several millimetres, if not more than a centimetre in size.”
While he found the rock in 2008, this is the first time Papineau was able to use modern techniques to study what is inside them. His team sliced it with a diamond-encrusted saw, creating sections as thin as 100 microns -- about the thickness of paper but double the thickness of previous cuts. This allowed a computer to create a 3D model showing larger structures inside the rock. Papineau told The Guardian he could see tiny filaments, knobs and tubes of an iron oxide called haematite that today are made by bacteria living around hydrothermal vents that survive on iron-based chemical reactions. However, this structure resembling a stem with branches filled with distorted spheres appeared to be more than a single life form.
“I think what we are seeing is a microbial community – that they were working in concert and as the filaments grew from groups of these cells, they got intermingled and made a bigger, thicker haematite filament.”
Taken together with the mineralized chemical byproducts in the rock, Papineau and his colleagues are convinced these are microbial life forms that existed 4.25 billion years ago -- just 300 million years after Earth was formed. And yes, this is a game-changing discovery.
“Pushing the clock back is very important, because it tells us that it takes a very short time for life to emerge on a planetary surface. Very quickly after [Earth formed] there was microbial life taking place, eating iron and sulphur in these hydrothermal vents.”
While it adds to Earth’s history, what Papineau is more excited about is that this means the search for alien life forms can be extended to extremely young exoplanets. Of course, this assumes the age and origin of his fossils is confirmed by other scientists, and some think it could just be a chemical metamorphism caused by the magma heat released from the hydrothermal vents.
So, this discovery of a potentially 4.25-billion-year-old fossil may not have changed everything yet, but it’s already affecting a lot of exciting things.