Scientists have found evidence of a huge asteroid that struck the Earth early in its life with an impact larger than anything humans have experienced.
Tiny glass beads called spherules, found in north-western Australia were formed from vaporised material from the asteroid impact, said Dr Andrew Glikson from The Australian National University (ANU).
"The impact would have triggered earthquakes orders of magnitude greater than terrestrial earthquakes, it would have caused huge tsunamis and would have made cliffs crumble," said Dr Glikson, from the ANU Planetary Institute.
"Material from the impact would have spread worldwide. These spherules were found in sea floor sediments that date from 3.46 billion years ago."
The asteroid is the second oldest known to have hit the Earth and one of the largest.
Dr Glikson said the asteroid would have been 20 to 30 kilometres across and would have created a crater hundreds of kilometres wide.