Earth May Have Once Had a Saturn-Like Ring, New Study Says

Saturn sports some of the coolest bling of any planet in our solar system. Its nine rings, which are mainly comprised of dust, rock and ice, have been the subject of scientific research for years. While Saturn's rings are the best known, Jupiter, Uranus and Neptune also have rings. And now, a new study published in the scientific journal Earth and Planetary Science Letters seems to show that Earth itself once had a similar ring.

The new study asserts that Earth's ring formed around 466 million years ago and stuck around for around 40 million years before dissipating. Researchers say that the existence of such a ring would help solve several puzzles from Earth's past and that much of the data they collected supports its existence.

The study starts with a period in history when things were rather tumultuous. Around 466 million years ago, scientists have found evidence that Earth suffered a veritable shower of meteors, and the meteorite impacts caused tsunamis, craters and other mayhem during that period. In particular, 21 high-impact meteorite craters were found to have occurred during that time. 

Read more: It's Not Too Late to Catch a Meteor Shower: Here Are All the Ones Left in 2024

Scientists used models of how Earth's tectonic plates have moved over that time to pinpoint where those impacts initially took place and found that all 21 impacts occurred close to the equator. This is odd, since meteorites can hit anywhere on the Earth's surface and seeing them all occurring around the same latitude on Earth with impacts around the same period would be an exceptional coincidence.

This led the researchers to propose that Earth once had its own ring, and that ring showered debris onto the Earth's surface, which would account for the patterns. 

The researchers believe that Earth's possible ring was generated by an asteroid that got a little too close for comfort. When something small like an asteroid comes too close to something larger, like Earth, it becomes stretched by gravity and falls apart. The theory purports that an asteroid came within Earth's Roche limit -- the distance at which the asteroid would fall apart due to Earth's gravity -- broke apart, and the remnants formed a ring that gradually rained down on Earth for tens of millions of years.

It's not a farfetched theory given that asteroids come pretty close to Earth all the time, and some even stick around for a bit as a second moon. 

"So if Earth destroyed and captured a passing asteroid around 466 million years ago, it would explain the anomalous locations of the impact craters, the meteorite debris in sedimentary rocks, craters and tsunamis and the meteorites' relatively brief exposure to space radiation," said Andrew Tomkins, the study's lead researcher. 

Tomkins and fellow researchers Erin Martin and Peter Cawood posit that a ring of debris around Earth would solve a few puzzles about Earth's past, including the aforementioned meteorite craters and tsunamis. The team is also exploring the idea that the ring shaded Earth from the sun, contributing to the intense amount of global cooling that caused the Hirnantian Ice Age, which was one of the coldest periods in Earth's history.