A team of geochemists at the University of California, Los Angeles (UCLA) have determined from evidences that precious life on Earth started at least 4.1 billion years. This incredible scope of life pertains to hosts of ancient microorganisms in what is presently the landmass of Western Australia. And if this credible hypothesis is confirmed than it could potentially change our studied comprehension of planetary life and its massive evolution pattern. More interestingly, it would suggest that the ambit of life is ‘almost’ as old as the Earth itself, with our home planet being around 4.54 billion years old.
In essence, the hypothesis put forth by the UCLA researchers suggests that there was life on Earth before the cataclysmic event that encompassed the massive bombardment of the inner Solar System around 3.9 billion years ago. During this time, the huge craters on the Moon surface were created by impacts of asteroids, while Earth also suffered immense degrees of damage. To that end, this calamitous scenario may have transformed Earth into a desolate, desert-like place with arid climate-zones that were incapable of sustaining life. Considering such impactful events of staggering proportions, it was widely conjectured that life was only formed (on Earth) 100 million years after this particular cataclysm – or around 3.8 billion years ago.
But in the recent times, many scientists groups (including the UCLA researchers) have put forward their analysed theory that such a cataclysmic event might not have affected Earth on such a large scale. As Mark Harrison, co-author of the research, said –
The early Earth certainly wasn’t a hellish, dry, boiling planet; we see absolutely no evidence for that. The planet was probably much more like it is today than previously thought.
Moreover, even if the massive bombardment did wipe out most of the existing life on Earth (prior to 3.9 billion years), the scope of life restarted pretty quickly after that – thus suggesting that old Earth was probably more like our present-Earth, as opposed to a desolate, uninviting planet. As for the actual assessment in question here, the scientists studied over 10,000 zircon specimens that are 4.1 billion years old from Western Australia. In geological terms, the zircons are durable minerals formed from molten rocks (magma), and are related to synthetic zirconium used for manufacturing fake diamonds.
However, beyond their physical properties, zircons have the ability to capture and preserve traces of their contemporary environments, thus essentially turning them into geological ‘time capsules’. And on examination, the researchers found mysterious dark speck-like matter formed inside 656 zircons. They chose 79 of these specimens, and further analyzed the stones by using Raman spectroscopy – which revealed the three-dimensional molecular and chemical structure of ancient microorganisms.
Intriguingly enough, when the scientists were searching the carbon (the key component of life), they also found graphite – the purest form of carbon, in one of these 79 zircons. Simply put, the zircon may very well denote a 4.1 billion-year-old graphite – a hypothesis that the researchers are pretty confident of, due to lack of any plausible alternative theory.
In essence, the study does allude how life has the ‘capacity’ to re-order and thrive rapidly than previously thought. And if we take the more tantalizing route, it also hints at the abundance of potential lifeforms in our universe. So, given the origination and restarting aptitude of these numerous lifeforms, it would too far-fetched to assume the possibility of alien life on the younger exoplanets around our system.
The study was originally published in the Proceedings of the National Academy of Sciences.