Earth might have had a ring system 466 million years ago

[Brian G Turner]

Absolutely fascinating idea:

Earth may have had a ring system 466 million years ago

In a discovery that challenges our understanding of Earth's ancient history, researchers have found evidence suggesting that Earth may have had a ring system that formed around 466 million years ago, at the beginning of a period of unusually intense meteorite bombardment known as the Ordovician...

phys.org

 

[Lady of Winterfell]

Another interesting theory. I'm sure it's possible. Saturn hasn't always had rings, so they aren't a phenomenon that is static or permanent. Perhaps they are more common than we think, and it's just the time period we are living in that determines how many we ring systems we actually observe.

 

[Brian G Turner]

The researchers have published their own commentary on The Conversation:

Hidden craters reveal Earth may once have had a ring – like Saturn

Mounting evidence suggests the rubble of an asteroid once formed a ring orbiting our planet’s equator.

theconversation.com

 

[Brian G Turner]

Phil Plait covers this in his newsletter, adding a few more important details to this theory:

The Earth may have had rings!

An asteroid broken up by Earth’s gravity may have given it rings long ago

badastronomy.beehiiv.com

The material would have been dark, but then the Moon’s surface is pretty dark material too, about as reflective as a blackboard. So the ring, sitting in full sunlight during the day, would’ve been pretty bright, easily visible. And at night, well. It would’ve been easy to read by ringlight. Imagine that view!

But it’s not all good news. The dense ring would also block sunlight, casting a shadow over a wide range of the planet depending on the season. Summer is when the axis of Earth is tipped toward the Sun, and the rings would then shadow the other hemisphere, the one experiencing winter. That means winters would have been extra cold. Reflected sunlight would warm the summer hemisphere, but only a little, and not nearly enough to offset the winter cooling. Not only that, but dust from the impacts would cool the Earth as well, though in general that doesn’t last long.

 

[Lady of Winterfell]

I do think the view of rings in the night sky would be pretty amazing. Thanks for the link to Bad Astronomy. I read Phil Plait's book Under Alien Skies last year and really enjoyed it. I forgot he had a newsletter, so now I can keep up with him.

 

[paranoid marvin]

It's also possible that those same rings clustered to form one heavenly body that illuminates Earth's night sky today.

 

[Robert Zwilling]

Any one have any guesses about how the Moon might have interacted with the ring?

 

[Swank]

It's also possible that those same rings clustered to form one heavenly body that illuminates Earth's night sky today.

The moon is 10 times as old.

 

[paranoid marvin]

The moon is 10 times as old.

It's possible that before it was a Moon, it was a collection of rocks and ice circling the Earth in a ring (or rings).

It's also possible that it wasn't.

 

[Brian G Turner]

It's also possible that those same rings clustered to form one heavenly body that illuminates Earth's night sky today.

That is a really interesting suggestion - there's still a lot of debate about how the Moon may have formed. The Apollo astronauts set up a reflector so laser measurements of its distance could be taken, which proved that the Moon is slowly moving away from the Earth. That seems to have given rise to the Theia impact hypothesis, suggesting that the Moon formed after an impact with the Earth over 4 billion years ago.

However, there are a few problems with that. Firstly, if you simply take the measurement of how fast the Moon is moving away and calculate it backwards, then that would given a formation date of around 1.5 billion years ago, which doesn't add up with Earth's geology. So the "solution" to this is to have the Moon simply static in orbit for 2.5 billion years, with no reasonable explanation as to how or why this happened. Additionally, having a stationary Moon kind of defeats the whole purpose of the theory of why it's moving away, undermining the Theia impact hypothesis. It's also worth noting that ordinary gravitational interactions are causing Titan to drift away from Saturn at a faster pace.

I'm not sure there's a fit for the Moon being involved in the 466 million year-old ring - all I can find out about L-type asteroids is that they are classified by their spectra and that explains nothing. It does raise interesting questions, though.

 

[Ursa major]

Apparently, the Earth is to get an asteroid** orbiting it in just over a week's time (but it won't be orbiting for very long).


** - Aka a "mini-moon"....

 

[Orcadian]

Surely much more likely to be a selection effect? Meteorites that fell in the sea will have left no trace after that length of time. Where were the continents actually located at that epoch? (Sadly cannot open the paper as "my browser is out of date".)

 

[Brian G Turner]

Surely much more likely to be a selection effect? Meteorites that fell in the sea will have left no trace after that length of time. Where were the continents actually located at that epoch? (Sadly cannot open the paper as "my browser is out of date".)

Basically, those areas we think were around at the equator at that time have craters - those land areas that were more than 30 degrees of it don't.

Also, back to the Moon - it's been recently discovered that it may have been volcanically active up to around 100 million years ago. I wonder if there's room for an argument for a particularly large eruption creating a ring around the Earth? After all, moons around Saturn and Jupiter are known to generate rings. Just thinking aloud.

 

[paranoid marvin]

Basically, those areas we think were around at the equator at that time have craters - those land areas that were more than 30 degrees of it don't.

Also, back to the Moon - it's been recently discovered that it may have been volcanically active up to around 100 million years ago. I wonder if there's room for an argument for a particularly large eruption creating a ring around the Earth? After all, moons around Saturn and Jupiter are known to generate rings. Just thinking aloud.

Entirely possible. Rings are essentially bits of rock and ice cauggt in the gravity of a planet. They have to come from somewhere. Assuming that most of the smaller bits and pieces floating through space have already been snared, the only place it can come from is the Moon or the Earth.

 

[Swank]

That would be quite an eruption to blow massive material off the moon, out of the moon's orbit and into earth orbit.

 

[Brian G Turner]

That would be quite an eruption to blow massive material off the moon, out of the moon's orbit and into earth orbit.

I don't think volcanism on the moon is going to result in the ring discussed in the original article - certainly not one containing meteorites that can create impact craters as big as reported. However, a geologically active moon creating a ring of material around its host planet is already the norm in the Solar System - Io already does this around Jupiter, and Enceladus around Saturn - but I can't recall seeing any references or research on what effect vulcanism might have had outside the Lunar environment. Certainly the potential to form rings of dust around the Earth would be the most commonsense expectation, but whether these had any significant effect on Earth and its climate is another matter.