Study Of Craters Suggests Earth Once Had Saturn-Like Rings

Earth has had a long history, but millions of years ago, the planet even had Saturn-like ring of debris around it. Surprised? A new study by Andy Tomkins and his colleagues at Monash University in Melbourne has suggested that the rings lasted for tens of millions of years, and may have affected the planet's climate. The study is based on the assessment of 21 asteroid craters from the 'Ordovician impact spike' period 466 million years ago. The researchers said these crater sites were caused by larger objects in a previously unidentified ring being pulled out of orbit and crashing into Earth.

The study has been published in Earth and Planetary Science Letters. The team noticed the asteroids that the craters were located in a narrow band of land close to the equator.

Asteroids normally strike at random locations, but looking at this pattern, researchers feel that it happened after Earth's close encounter with a large asteroid millions of years ago.

They have theorised in the study that the asteroid broke apart due to tidal forces and formed a debris ring around our planet, similar to the rings seen around Saturn.

"Over millions of years, material from this ring gradually fell to Earth, creating the spike in meteorite impacts observed in the geological record," Mr Tomkins was quoted as saying by The Independent.

"We also see that layers in sedimentary rocks from this period contain extraordinary amounts of meteorite debris," he explained.

But how did the craters emerge so close to the equator? Mr Tomkins and his team point to the movement of continents due to plate tectonics. They say at that time, all the sites would have been located close to the equator.

The team also relied on previous research having identified a consistent meteorite signature in a number of limestone deposits, also from that time and also once close to the equator.