Anyone who has seen Saturn Through It’s amazing to see it through a telescope The system of rings surrounding Saturn. The rings are made of rock and ice and extend for thousands of kilometers around the planet. Although rings are a distinctive feature of Saturn, Jupiter, Uranus and Neptune also have ring systems around them, although they are less dramatic.
But it doesn’t have to be a giant planet. I have a ringAs debris continues to accumulate in the planet’s gravity well, its rotation will cause a ring to form near its equator. There are various ways in which rings form, but one way is when an asteroid gets too close to the planet and is captured, then crushed by the tidal forces of the planet’s gravity.
The ring of the Earth?
The Oldovidian ring and the impact date cited as evidence of a collision, tsunami deposits (Megabresia), L chondrite deposits, and global temperatures culmination. Credit: Tomkins et al. (2024)
a New research paper Andrew Tomkins and other journal authors Earth and Planetary Sciences They make a bold claim that Earth may have had a ring system in the past: by looking at crater locations, evidence of marine deposits, and some intriguing climatic coincidences, they suggest that rings made from broken-up asteroids swept across Earth’s sky starting around 465 million years ago and lasting between 20 and 40 million years.
Tomkins and his colleagues Ordovician (approximately 485-443 million years ago) Impact rates on Earth appear to be high based on evidence from preserved craters. Combine this with the surge in material from certain types of asteroids, and it’s clear that Earth is receiving more debris from space.
One hypothesis is that something happened in the asteroid belt, sending small chunks of rock into the inner solar system. This would explain the increased craters and asteroid-derived material in the deposits (2-3 times more than usual), but there is no evidence that further impacts of this age happened on Mars or the Moon. Why only Earth?
Tomkins and his colleagues reasoned that if all the material from the asteroids was the same (L chondrites It seems plausible that only one object could have been its source, perhaps an asteroid that came too close to Earth.
The death of an asteroid, the birth of a ring
Reconstruction of the Ordovician impact sites. These impacts are speculated to have been caused by fragments of asteroids that came too close to Earth. Source: Tomkins et al. (2024).
They used plate tectonics reconstruction methods to reconstruct the world map from that time, and found that the major impacts preserved from that era (at least 21 of them!) fall within a range that makes them unlikely to be random: rather, they can be explained as a series of large impacts by some kind of celestial body that got too close to Earth and was crushed.
The asteroid rained down on Earth in small fragments, rather than a single giant impact. After the asteroid broke up near Earth, it formed a new ring around the planet. Then, over 40 million years, all the fragments fell out of orbit. As all this debris fell to Earth, the L chondrite material was elevated in the world’s sediments, but fell back when the ring disappeared.
There is also evidence in the rock record that large tsunamis and earthquakes were common during this period, which could be explained by numerous asteroid impacts over the last 40 million years that generated giant waves and piled up debris on the shores of the supercontinents and small landmasses that existed at the time.
Have your climate questions been answered?
The theory of the Earth’s ring system proposed by Tomkins and his colleagues was able to answer several vexing questions. The Earth’s climate has cooled But the carbon dioxide remained high in the atmosphere. As we know from current climate change, carbon dioxide should increase temperatures, but if the rings were covering part of the Earth and reflecting sunlight, the climate would cool. If you add in the dust that would be lifted into the air from material that rained down over millions of years, the total effect could be a cooling of as much as 8 degrees.
Climate records also suggest that Earth warmed again about 440 million years ago, which, according to Tomkins’ ring theory, would coincide with the time when the rings appear to have disappeared, potentially destroying any small moons that formed during this time.
It’s interesting to think about what the ringed Earth would have looked like from above. Sadly, the surface of the Earth was largely devoid of life, except for some of the earliest land plants. All the animals on Earth lived in a vast ocean At the time, the rings covered most of the Earth, but if the rings had extended into space, Earth would look very different than it does today.
