Earth may have a giant ring of space rocks surrounding it, similar to the one around Saturn, which could lead to catastrophic meteorite strikes on our planet’s surface, new research suggests.
The hypothesized rings probably formed about 466 million years ago and are the remains of a giant asteroid that was pulled apart by Earth’s tidal forces after it passed our planet. Roche Limit.
By casting a shadow across Earth’s equator, the rings may have contributed to global cooling events by blocking sunlight, while also bombarding the surface with meteorites. The researchers published their findings on September 16 in the journal Earth and Planetary Science Letter.
“Over millions of years, material from these rings gradually fell to Earth, creating the spike in meteorite impacts observed in the geological record,” said the study’s lead author. Andy Tomkinsa professor of planetary science at Monash University in Australia, said in a statement“We also saw that the sedimentary rock layers from this period contain large amounts of meteorite debris.”
Scientists arrived at their surprising hypothesis by studying a period in Earth’s history known as the Ordovician (485 million to 443 million years ago). The Ordovician was a tumultuous time for our planet — it was one of the coldest in the past 500 million years and saw a dramatic increase in the rate of meteorites hitting Earth.
Related: Can scientists stop a ‘planet killer’ asteroid from hitting Earth?
To investigate what might be causing this effect, scientists mapped the positions of 21 Ordovician asteroid impact craters, revealing that all of the impacts occurred within 30 degrees of Earth’s equator.
Since 70% of Earth’s continental crust lies outside this region, the researchers calculated that the chances of this happening by chance were the same as rolling a three-sided die 21 times and getting the same result 21 times.
With these highly unlikely odds in mind, researchers came up with a hypothesis that could explain the equatorial impact and planetary cooling — a ring, the remains of shattered asteroids, surrounding Earth at the equator.
More evidence is needed to support the hypothesis, but the ancient ring theory could explain many aspects of Earth’s history, especially if the rings appeared more than once above our planet before slowly being erased as asteroids were sucked away by its gravity, the researchers said.
“The idea that ring systems can influence global temperatures adds a new layer of complexity to our understanding of how extraterrestrial events can shape Earth’s climate,” Tomkins said.