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Famous for its extensive ring system, Saturn is one of the four planets in our solar system that have this particularity. And now scientists are hypothesizing that Earth may have sported its own ring around 466 million years ago.

During the Ordovician perioda time of significant change to life forms, plate tectonics, and Earth’s climate, the planet experienced a spike in meteor strikes. According to a study published on September 12 in the journal Scientific letters from the Earth and planets.

“It is statistically unusual to have 21 craters all relatively close to the equator. This shouldn’t happen. They should be randomly distributed,” said lead author Andrew Tomkins, a geologist and professor of earth and planetary sciences at Monash University in Melbourne, Australia.

Not only does the new hypothesis shed light on the origins of the increased number of meteorite impacts, it may also provide an answer to a previously unexplained event: a global deep freeze, one of the most colds in Earth’s history, could have been a result of the ring’s shadow.

Scientists hope to learn more about this possible ring. This could help answer mysteries of Earth’s history and ask new questions about the influence an ancient ring might have had on evolutionary development, Tomkins said.

When a smaller object gets close enough to a planet, it reaches what is called the Roche limitthe distance at which the celestial body exerts sufficient gravitational pull to break the approaching body. The resulting debris then creates rings around the planet, like those around Saturn which could have been formed by debris from icy moons, according to NASA.

Scientists previously thought that a large asteroid broke apart within the solar system, creating the meteorites that struck Earth during the Ordovician period. However, such an impact would likely have made the strikes more random, like randomizing craters on the moon, Tomkins said.

The study authors hypothesize that a large asteroid, estimated at around 12 kilometers in diameter, would have instead reached Roche’s terrestrial limit, which could have been around 9,800 miles (15,800 kilometers) of the planet based on measurements of ancient asteroids in rubble piles. The asteroid would have been largely destroyed by other collisions, making the rubble easy to disassemble by Earth’s tidal force, Tomkins said.

The ring is thought to have formed along the equator due to Earth’s equatorial bulge, in the same way that the rings of Saturn, Jupiter, Uranus and Neptune are also found around the equatorial planes of each of these planets, a he added.

About 200 impacts are known throughout Earth’s history, Tomkins said. By examining how Earth’s landmasses have shifted over time, the authors found that all 21 known craters from the Ordovician period were near the equator. Additionally, only 30% of the Earth’s surface area suitable for preserving a crater was near the equator. If the impacts had been random and not caused by a ring, most of the craters would have formed far from the equator, he added.

The authors also point out a study from February 2022 who analyzed impact craters on the Earth, Moon and Mars, and found signs of an Ordovician impact peak only on Earth, adding evidence that fits the ring theory.

“The paper presents a nice idea that ties together a few mysteries,” said astrophysicist Vincent Eke, an associate professor at the Institute of Computational Cosmology at the University of Durham in the United Kingdom, who was not involved in the study. new study.

The research analysis revealed several deposits on Earth dating from the same time period as the impact craters, containing high levels of L chondrite, a common meteoritic material, that showed evidence of shorter exposure to space radiation than meteorites found today. The discovery suggests that a large altered space The asteroid that likely strayed into Roche’s Earth boundary disintegrated near the planet, the study authors wrote.

A few million years after the period of increased meteor impacts, around 445 million years ago, there was a dramatic decrease in global temperatures on Earth, known as the Hirnantian Age.

“Debris resulting from such an event (a potential ring) could explain these three observations,” Eke said in an email, referring to impact craters, meteorite debris and global climate change.

The study authors are investigating how much shadow would be needed to cause a deep global freeze, a finding that could in turn help estimate the ring’s opacity, Tomkins said. Similarly, the Earth could have been cooled by dust clouds resulting from meteorite impacts, he added.

Tomkins said he hopes future research will establish how long the ring persisted and shed light on how it might have influenced the evolutionary changes Earth faced, likely due to difficult climatic conditions. “Understanding the causes of climate change on Earth can also help us think about the evolution of life,” he added.

It’s difficult to say what such a ring would have looked like without knowing the density of the material, but Tomkins estimates that even a faint ring would have been visible from Earth.

“If you were on the night side of Earth and the sunlight was shining on the rings, but not on you, that would probably make them visible in quite an interesting way – it would be quite spectacular,” he said.

Based on the length of the global cooling period and the dating of craters and meteorites, the possible Earth ring could have lasted 20 to 40 million years, Tomkins said. Collisions between other particles would have caused space rocks to be thrown out of the ring.

Previous research have discovered that ancient Mars could also have sported one or more rings, and scientists predict that the planet could one day have more in the future.

“While the rings are currently associated with the outer giant planets of the solar system, within the next 100 million years Mars is expected to acquire a ring system when its inner moon, Phobosspirals inside the rigid Roche radius and is itself torn,” Eke said in an email. “Fortunately, for the development of life on Earth, this type of event is rare at present!

Since the end of September, an asteroid named 2024 PT5 has been traveling near Earth. The space rock is commonly called a “mini-moon” because it is less than 4.5 million kilometers from the planet. However, even during the asteroid’s closest pass to date, on August 8, at about 352,300 miles (567,000 kilometers), it was far from Roche’s Earth boundary, Carlos de la Fuente Marcos said, researcher at the Faculty of Mathematical Sciences of the Complutense University of Madrid who studied the mini-moon. De la Fuente Marcos was not involved in the new study.

Furthermore, the suggested Earth ring “should have been the result of the disruption of a much larger body as the authors indicate in their paper,” he added in an email, so the asteroid, probably about 37 feet (11 meters) in diameter, could not have created a new ring for Earth.

“You’d have to capture a big one and place it in exactly the right orbit to break it up. … (This mini-moon) is just one example of the processes that are happening in our near space zone that can lead to the kind of thing we’re talking about,” Tomkins said. However, “we believe this ring-forming event has only occurred once in the last 500 million years.”