If you think of ‘planet killer’ asteroids, the most notorious is the one which wiped out the dinosaurs.
In making T-Rex and Stegosaurus extinct, it changed the course of evolution and left us with only chickens as their closest descendants.
But another meteorite might have had an even bigger impact, potentially even helping life to thrive in the first place.
A huge space rock four times the size of Mount Everest named S2 is thought to have crashed into Earth around 3.26 billion years ago, scientists said.
Up to 200 times the larger than the one spelling dino-doom, it was so huge that it made the ocean boil and caused the largest tsunami ever recorded, the research published in the journal PNAS yesterday said.
Researchers travelled to the impact crater caused by the 37-58km meteorite in South Africa’s Barberton Greenstone belt to see how it affected the planet.
Analysis suggests the huge tsunami it triggered mixed up the ocean and flushed debris from the land into coastal areas.
Heat from the impact caused the topmost layer of the ocean to boil off, while also heating the atmosphere, and causing a thick cloud of dust to blanket everything making the sky dark, experts say.
But though this doesn’t sound like the most pleasant conditions to live through, the researchers theorise that life might actually have thrived after the hit.
Nadja Drabon, an early-Earth geologist and assistant professor in the department of Earth and planetary sciences, University of Harvard, USA, said: ‘We think of impact events as being disastrous for life.
‘But what this study is highlighting is that these impacts would have had benefits to life, especially early on … these impacts might have actually allowed life to flourish.’
This is because iron was likely stirred up from the deep ocean into shallow waters by the tsunami, while phosphorus was brought to the planet by the meteorite itself and from an increase of erosion on land.
With this came sharp spikes in populations of single-celled organisms that feed off the two elements.
The study concluded: ‘Giant impacts were not just agents of destruction but also conferred transient benefits on early life.’
It would still be a big problem if one hit Earth again though.
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