There is something undeniably cool about the idea that all life on Earth began with a meteor impact that happened to carry the essential elements of life, which mixed with the primordial soup we already had. Billions of years of cooking later, and here we are, a thriving civilization just starting to reach out to the stars.
Well, it might not have gone down that way, if some new research published in Scientific Reports by scientists at the University of Cambridge and the University of Edinburgh is to be believed. The research teams ran 100,000 computer simulations of early Earth’s comet bombardment, and the math simply does not check out.
Comets burn as they enter our atmosphere at preposterously high speeds, creating a thermal force of impact that vaporizes delicate organic compounds way before they can reach the soil, according to the researchers. Across their simulations, 54 percent of runs resulted in zero successful deliveries of hydrogen cyanide, a chemical compound integral to the formation of life.
Scientists Say Comets May Not Have Brought the Ingredients for Life to Earth After All
The remaining 46 percent yielded 87 comets that could conceivably seed life, with only one mildly successful, one-in-a-million fluke strike that deposited the exact chemistry needed to enable you to read my words right now. Even then, rain or the oceans would dilute that little bit of life-giving chemistry within weeks, further stretching the already thin odds of life emerging from a comet strike.
The study authors noted that if comets did manage to seed life anywhere in our solar system, it probably happened on Mars, thanks to its weaker gravity and thinner atmosphere, essentially creating a cosmic cushion that would soften comets’ impact. Simulations yielded over five times as many successful chemical deliveries as on Earth. In case you were wondering, Venus’s atmosphere is so thick that a comet would be obliterated before it ever touched down.
None of this definitively kills the theory, as research teams worldwide still have plenty of work to do, but it does raise questions other teams can now address. As for alternative theories proposed by the researchers, well, they aren’t that different from the original theory: instead of comets, it could’ve just been asteroids, because there is a difference between the two, and it’s much more likely that an asteroid would hit the Earth rather than a comet, as the original theory states. They are also totally open to the idea that the Earth already had everything it needed to create life.
We may never get a definitive answer, but for now we can be thankful that it happened at all.
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