The effects of ancient asteroid impacts on Earth are still evident from the variety of impact craters across our planet. And from the Chelyabinsk event back in 2013, where an asteroid exploded in the air above a Russian town, we know how devastating an “airburst” event can be.
Now, researchers in Antarctica have discovered evidence of a strange intermediate-type event – a combination of an impact and an airburst. The event was so devastating, its effects are still apparent even though it took place 430,000 years ago.
If you asked someone who was reasonably scientifically literate how Earth got its water, they’d likely tell you it came from asteroids—or maybe comets and planetesimals, too—that crashed into our planet in its early days. There’s detail, nuance, and uncertainty around that idea, but it’s widely believed to be the most likely reason that Earth has so much water.
But a new explanation for Earth’s water is emerging. It says that the water comes along for the ride when Earth formed out of the solar nebula.
If that’s correct, it means that most rocky planets might have water for at least a portion of their lives.