WASHINGTON, Dec 1: A single, gigantic asteroid slammed into Earth 65 million years ago, dooming the dinosaurs and many other species, scientists said on Thursday in a new study rebutting theories that multiple impacts did the deed.

An examination of rock sediments drilled from five sites at the bottom of the Atlantic Ocean strongly supports the notion that one massive hunk of space rock caused the mass extinction, a research team led by University of Missouri-Columbia geology professor Ken MacLeod found.

“It’s a completely straightforward, single-impact scenario,” Mr MacLeod, whose findings appear in the Geological Society of America Bulletin, said in an interview.

Scientists believe that an asteroid about 10kms wide hurtled to Earth 65.5 million years ago at the end of the Cretaceous Period, plunging into what is now Mexico’s Yucatan Peninsula to carve out the Chicxulub crater measuring 180kms across.

To put it mildly, it was a bad day to live on Earth.

The impact triggered a worldwide environmental catastrophe, many scientists believe, expelling vast quantities of rock and dust into the sky, unleashing giant tsunamis, sparking global wildfires and leaving Earth shrouded in darkness for years.

The dinosaurs, which had ruled for 160 million years, were wiped out. So were large marine reptiles, the flying reptiles known as pterosaurs and many species of marine plankton.—Reuters