When you think of life emerging on Earth, you might imagine molecules and isotopes bubbling in a primordial soup like in that episode of Star Trek: The Next Generation where Q time-warps Picard to our planet billions of years ago. Now scientists think the first life on Earth could have crawled out even more billions of years ago.
Could life really have formed in the cosmological blink of an eye after the Big Bang? Tsuyoshi Komiya and his team of scientists think so. After unearthing 3.95-billion-year-old graphite from rocks at Saglek Block in Labrador, Canada, and analyzing its graphite and carbon isotopes, they found that it was biogenic. Meaning, it came from something alive.
Earth was a hostile place when it came into being. If you could see past the haze of methane and ammonia that passed for an atmosphere, you would find a temperamental planet seething with magma, exploding with volcanic eruptions and being bombarded by comets and asteroids. It is almost impossible to imagine anything surviving on this battleground except maybe a tardigrade. Somehow, something was able to make it through this volatile era and withstand the fire-scorched surface and choking air long enough to leave a trace of itself behind.
Evidence of primordial life does not reveal itself easily because the ravages of time have long since turned most of it to dust. Even most of the rocks in which it lies hidden have either disintegrated or been disfigured beyond recognition. If the observations of Komiya’s team are accurate, this could mean that life first spawned anywhere from 150 to 250 million years before we assume it did.
While the identity of this organism is still in the dark, the type of life it was could be determined by additional testing for iron, sulfur, nitrogen, and phosphorus isotopes that may be hiding in what remains of it. It could also illuminate how early life evolved on Mars and beyond—if there was any life there to begin with.
“The discovery of the biogenic graphite enables geochemical study of the biogenic materials themselves, and will provide insight into early life not only on Earth but also on other planets,” said Komiya and colleagues in a study recently published in the journal Nature.
The chemical composition of the sample could provide insight as to whether biological processes started by some “magic” combination of isotopes on our planet, or whether some of these came crashing to Earth via the comets and asteroids that relentlessly pummeled it during the Eoarchaean era. If scientists figure out how to elucidate that, they could apply the same to Mars and any other planet or moon (Enceladus anyone?).
For now, just let your mind be officially blown by the fact that there have been things creeping around on Earth for almost 4 billion years.