The space rocks, which struck in the sea, would have caused devastating tsunamis, and could have even wiped out some species, scientists believe.
Erik Sturkell, professor of geophysics at the university, said: “Around 470 million years ago, two large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland.
“Information from drilling operations demonstrates that identical sequences are present in the two craters, and the sediment above the impact sequences is of the same age.
“In other words, these are simultaneous impacts.”
At the time Jämtland was under a shallow sea.
The twin impact could have had devastating effects like the subsequent asteroid which finished off t
Two large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland
The Chicxulub crater in Mexico was determined to be about 65million years old, and is believed to have triggered the end of the dinosaurs.
Another crater, found in Antarctica, may have caused the greatest mass extinction on Earth, some 250 million years ago.
Scientists suggest that this impact may have played a role in the breakup of the Gondwana supercontinent.
Doomsday theorists are claiming a huge asteroid will wipe out life as we know it between tomorrow and September 28.
But, although we have a number of so-called near earth passes scheduled over the next few days, US space agency Nasa says nothing is scheduled to hit earth for several hundred years.