Earth may have had a Saturn-like ring over 400 million years ago, scientists say

Saturn is well-known for its extensive ring system, a feature it shares with other planets like Jupiter, Uranus, and Neptune. However, scientists now propose that Earth might have had its own ring approximately 466 million years ago. During the Ordovician Period, a time marked by significant meteorite strikes, researchers suggest these impacts may have originated from a rocky ring surrounding Earth.

This hypothesis arises from the unusual concentration of impact craters near the equator, which would typically be randomly distributed. The potential ring could also explain a significant climate event, a global deep freeze in Earth's history, possibly caused by the ring's shadow.

Understanding how rings form involves the concept of the Roche limit, the distance at which a celestial object's gravitational forces can pull apart an approaching body, potentially creating rings. Scientists previously considered a large asteroid collapse responsible for the meteorites, but this new theory suggests an asteroid may have reached Earth's Roche limit and disintegrated into debris forming a ring.

This ring is believed to have formed along the equator due to Earth's equatorial bulge, drawing parallels with those of other ringed planets. The proposed ring's influence on Earth's climate and life evolution remains a subject of further study. The possibility of such a ring would not only be a spectacle but also a significant factor in Earth's prehistoric climate shifts.

The ancient debris might have caused a drop in global temperatures millions of years later. It is estimated that such a ring could have lasted between 20 to 40 million years. While similar phenomena have been predicted for Mars in the future, the occurrence of rings around a planet like Earth is considered rare in contemporary times.

In recent observations, an asteroid named 2024 PT5, referred to as a "mini-moon," has been traveling near Earth, but its proximity is nowhere near the Roche limit required to form a ring. Creating a new ring would necessitate capturing a much larger asteroid and it entering an exact orbit to break up.

While discussions and speculations about ancient Earth rings continue, any future occurrences of such formations are currently regarded as unprecedented.