In a paper published in Earth & Planetary Science Letters, my colleagues and I present evidence that Earth may have had a ring.

The existence of such a ring, forming around 466 million years ago and persisting for a few tens of millions of years, could explain several puzzles in our planet's past.

The case for a ringed Earth

Around 466 million years ago, a lot of meteorites started hitting Earth. We know this because many impact craters formed in a geologically brief period.

In the same period we also find deposits of limestone across Europe, Russia and China containing very high levels of debris from a certain type of meteorite. The meteorite debris in these sedimentary rocks show signs that they were exposed to space radiation for much less time than we see in meteorites that fall today.

Many tsunamis also occurred at this time, as can be seen from other unusual jumbled up sedimentary rocks.

We think all these features are likely related to one another. But what links them together?

A pattern of craters

We know of 21 meteorite impact craters that formed during this high-impact period. We wanted to see if there was a pattern in their locations.

Using models of how Earth's tectonic plates moved in the past, we mapped out where all these craters were when they first formed. We found all of the craters are on continents that were close to the equator in this period, and none are in places that were closer to the poles.