Evidence suggesting that earth had a ring in the Ordovician

September 19, 2024 8:14 AM

All large planets in our Solar System have rings, and it has been suggested that Mars may have had a ring in the past. This raises the question of whether Earth also had a ring in the past.
posted by bq (23 comments total)

The sunsets would have been amazing. Anyone who believes that they have been born into the wrong era clearly lack a great deal of ambition.
posted by mhoye at 8:52 AM on September 19 [4 favorites]

I would love to see an artist’s illustration of the ring as seen from the ground. It might also be incredible to visit all those crater sites. To think that there were creatures living here, with a ring in the sky!
posted by Flight Hardware, do not touch at 9:25 AM on September 19

It were cast into Mount Doom woznit?
posted by k3ninho at 10:01 AM on September 19 [3 favorites]

Could we make a new one, to fight global warming? I'm sure it's a great idea.
posted by GenjiandProust at 10:36 AM on September 19 [1 favorite]

Does a ring of spacejunk and starlink comsats count?
posted by ApathyGirl at 10:53 AM on September 19 [7 favorites]

If we liked it should’ve put a ring on it.
posted by TedW at 10:57 AM on September 19 [7 favorites]

Now I'm wondering what the mass and trajectory of that asteroid was that it was juuuuuust arriving in such a way to be torn apart, but not to just come smacking down in one go.
posted by slater at 11:05 AM on September 19

What a lovely thing that would have been to see. I hope some weird jawless fish or eel or something looked up and thought "that's nice".
posted by pattern juggler at 11:19 AM on September 19 [6 favorites]

A ring around a flat circle? Why not?
posted by Greg_Ace at 11:32 AM on September 19 [2 favorites]

I was working on a post about this last night which began with...

The researchers speculate that the ring could have cast a shadow on Earth, blocking sunlight and contributing to a significant global cooling event known as the "Hirnantian Icehouse."

Earth may have had a ring system 466 million years ago

The rings may have been responsible for the last episode of Snowball Earth during the Ordovichian...

The title would have been SnowBall Earth, Now With Rings
posted by y2karl at 11:50 AM on September 19 [1 favorite]

From the Earth may have had a ring system 466 million years ago

Normally, asteroids impact the Earth at random locations, so we see impact craters distributed evenly over the moon and Mars, for example. To investigate whether the distribution of Ordovician impact craters is non-random and closer to the equator, the researchers calculated the continental surface area capable of preserving craters from that time.

They focused on stable, undisturbed cratons with rocks older than the mid Ordovician period, excluding areas buried under sediments or ice, eroded regions, and those affected by tectonic activity. Using a GIS approach (Geographic Information System), they identified geologically suitable regions across different continents.

Regions like Western Australia, Africa, the North American Craton, and small parts of Europe were considered well-suited for preserving such craters. Only 30% of the suitable land area was determined to have been close to the equator, yet all the impact craters from this period were found in this region.

The chances of this happening are like tossing a three-sided coin (if such a thing existed) and getting tails 21 times.

posted by y2karl at 12:08 PM on September 19

See also

Highlights

• Earth may have had a ring during the middle Ordovician, from ca. 466 Ma.

• Breakup of an asteroid passing within Earth's Roche limit likely formed the ring.

• Among several features preserved is a near-equatorial band of impact craters.

• Shading of Earth by the ring may have triggered a global icehouse period.

Evidence suggesting that earth had a ring in the Ordovician

Which is loaded with related scientific linkage in its footnotes.

I am getting the impression that ringed planets were more the rule rather than the exception in the early Solar system
posted by y2karl at 12:30 PM on September 19

The three-sided coin thing was odd. I'm not sure why they didn't say same as the odds of flipping a coin 35 times and getting tails every time.
posted by tavella at 12:48 PM on September 19 [4 favorites]

I hope some weird jawless fish or eel or something looked up and thought "that's nice".

Someone made a comic on that theme.
posted by tavella at 12:56 PM on September 19 [1 favorite]

> I would love to see an artist’s illustration of the ring as seen from the ground.

Here are a bunch of visualisations by Kevin Gill.
posted by lucidium at 2:41 PM on September 19 [4 favorites]

The three-sided coin thing was odd. I'm not sure why they didn't say same as the odds of flipping a coin 35 times and getting tails every time.

Agree completely. I think they're basically saying 30% ~ 1/3, and I guess they observed 21 events...

Strange to make a metaphor to explain how unexpected a real observation that references a hypothetical thing that few apart from maybe Buckminster Fuller have even contemplated. It would have been somehow more intuitive to say "It's like rolling a 10-sided die 21 times and rolling.8 or higher every time!" Ok....
posted by dsword at 3:48 PM on September 19

Here are a bunch of visualisations by Kevin Gill.

Pardon my pickiness but if we had rings like that now, wouldn't there chunks coming down rather frequently and making short work of us all? No green trees then. A landscape other than lunar is hard to imagine until the rings all fall down or so I would think..
posted by y2karl at 4:21 PM on September 19

Radiodonts assemble!
posted by Captaintripps at 8:12 PM on September 19 [1 favorite]

> wouldn't there chunks coming down rather frequently and making short work of us all?

In an established system, I believe the majority of the particles would be small enough (<~10m) to burn up, and any that did hit land would be in a narrow strip along the orbit. Just don't buy property in Ringfall Alley.
posted by lucidium at 2:59 PM on September 20

and any that did hit land would be in a narrow strip along the orbit

This is what the paper claims as the key piece of evidence, that the craters seem to be concentrated along the equator.

I don't know what all the evidence is, or what is the quality of the evidence. However, the first known land plants are from the Ordovician, so it's fun to speculate that these meteor events and the accompanying ice ages might have been hindering the development of life on land, which finally took off after the bombardment was done.
posted by polecat at 3:57 PM on September 20

Exactly.
posted by y2karl at 5:03 PM on September 20

I recently learned that sharks are older than some stars (450 mya versus the 100 mya Pleiades) and don't know how to comprehend that sort of deep time. Maybe sharks are even old enough to have looked up at rings in the sky!
posted by autopilot at 1:06 AM on September 21

Um... see polecat last sentence.
posted by y2karl at 10:03 AM on September 21