Astounding ancient asteroid

Tiny glass beads found in Western Australia hint at the impact of an enormous asteroid 3.46 billion years ago. Andrew Glikson from The Australian National University (ANU) and colleagues identified the spherules in ancient sea floor sediments although their location does not point to an impact site for the 20-30 kilometer-wide rock because millions of years of plate tectonic movement and volcanic activity have erased any trace of a crater. "The impact would have triggered earthquakes orders of magnitude greater than terrestrial earthquakes," says Glikson, "it would have caused huge tsunami and would have made cliffs crumble and the material from the impact would have spread worldwide."