Scientists have long known that early Earth was a turbulent place where asteroids regularly assaulted the planet’s crust. But recently, scientist quantified just how intense that assault really was.
According to a new model, out July 30 in Nature, early Earth was “pummelled by an enormous flux of extraterrestrial bodies,” wrote the authors. Earth could have been hit by up to four cosmic projectiles larger than 600 miles in diameter, just under the width of Texas. Three to seven more impactors were likely about half that size, but still capable of “global ocean vaporization,” according to the researchers. That’s not to mention all the “little” ones.
You can see how the planet would have looked in the GIF below:
“Hadean” Earth — which lasted from Earth’s birth, 4.5 billion years ago, up to 4 billion years ago — has always been a bit of a mystery.
“Little is known about that period simply because the Earth is a very geologically active planet where surface rocks are continuously recycled,” lead author Simone Marchi from the Southwest Research Institute in Boulder, Colorado told Business Insider in an interview.
Since there are no rocks on Earth older than about 3.8 billion years old, the latest study looked to the marks left by asteroids on Earth’s neighbours: the moon, Mars, and Mercury. Looking at the impact data from these planets, as well as the size distribution of our current asteroid belt, the scientists recreated early Earth.
The cosmic pummelling could have vaporized oceans and turned rock to lava. It also could have created the oldest known bits of Earth.
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