Earth Also Had Saturn-Like Ring Around It, Study Reveals; How It Disappeared

New Delhi: Earth used to have a Saturn-like ring of debris around it, over 450 million years ago, a study has revealed. The study by Andy Tomkins and his colleagues at Monash University in Melbourne based on the assessment of 21 asteroid craters from the 'Ordovician Impact Spike' period 466 million years ago suggested that the rings around the Earth lasted for tens of millions of years. The ring might have possibly affected the climate of the Earth as well. 

How Did The Ring Around Earth Disappear?

As per the study, scientists believe that the ring has fallen into Earth causing meteor strikes near the equatorial regions of the Earth. The remains of a massive asteroid were likely caught by Earth's gravitational pull, suggests a study published in Earth and Planetary Science Letters. This is the reason why sedimentary rocks from this time contain 99 % L chondrite material (parent body in the asteroid belt) at abundances 2–3 orders of magnitude above background, with extremely brief CRE ages.

"Over millions of years, material from this ring gradually fell to Earth, creating the spike in meteorite impacts observed in the geological record," the lead author Andy Tomkins, a professor of planetary science at Monash University in Australia said. "We also see that layers in sedimentary rocks from this period contain extraordinary amounts of meteorite debris," he added.

According to the research, all the impacts occurred within 30 degrees of the equator despite over 70 per cent of the continental crust of Earth being outside this region, which cannot be explained by conventional theories. 

How Did The Earth's Ring Impact The Climate? 

Scientists suggest that the ring around Earth might have some climate implications as it used to block sunlight. It also contributed to a significant global cooling event also called the Hirnantian Icehouse. “We further speculate that shading of Earth by this ring may have triggered cooling into the Hirnantian global icehouse period,” the report reads.

Mars Also Had Rings!

The study also reveals that all large planets in our solar system have rings. Moreover, it claims that Mars also may have had a ring in the past. The study also suggested that the resulting fragments formed a debris ring that decayed over several tens of millions of years resulting in an anomalous spike in impact cratering rate.

"We have suggested that a large L chondrite asteroid had a near-miss encounter with Earth at ca. 466 Ma, which caused it to break up as it passed through Earth's Roche limit. This can explain why sedimentary rocks from this time contain 99 % L chondrite material at abundances 2–3 orders of magnitude above background, with extremely brief CRE ages. We have further suggested that the resulting fragments formed a debris ring that decayed over several tens of millions of years resulting in an anomalous spike in impact cratering rate. This hypothesis may explain why all impact structures from this time are located proximal to the equator; impacts from bodies originating in the asteroid belt are expected to be randomly distributed across the globe. We have estimated the probability that this impact structure distribution resulted from random unrelated impactors at 1 in 25 million. We speculate that this ring may have promoted the coldest global cooling event in the last 540 million years, the Hirnantian Icehouse period.' the summary of the report reads.