When Earth had rings | Hacker News Reader

When Earth had rings

nautil.us

127 pointsrbanffy49 comments

I find myself, perhaps irrationally, quite irked that the picture headlining the article uses a picture of current Earth with rings, when Earth's surface 466 million years ago looked much different[1]. The paper itself [2] does have a map, although (understandably) not an artist's depiction. Most other sources covering the paper appear to have repurposed "ringed terrestrial planet" artwork, but I found one has an artist's rendition[3] to mollify myself.

1. https://dinosaurpictures.org/ancient-earth#450 2. https://www.sciencedirect.com/science/article/pii/S0012821X2... 3. https://www.yahoo.com/news/earth-had-saturn-rings-466-182200...

I live in the Netherlands, which has a province reclaimed from the sea in the 20th century. You'd be surprised how many documentaries of "Europe during the ice ages" etc show this province (Flevoland) on their maps. Always makes me chuckle.

Well I know may previously low lying areas become inundated by the sea after the ice age ended. I thats the case with Doggerland which was believed to be inhabited previously and now is home to fish. I wonder if some of the reclaimed land in your country was previously above the water table before being flooded by rising sea levels before being reclaimed by man?

Yes, the entirety of the Netherlands was hundreds of kilometres inland during the last ice age, up to 10000 years ago. So I guess it should have been all solid land, Flevoland included.

Here's a map of what the region would have looked like:

https://www.ecomare.nl/en/discover-ecomare-on-texel/expositi...

Exactly. The ones that made me chuckle had a clear outline of the current province. Didn't keep notes so don't have any examples unfortunately.

I was about to write this complaint myself then I found your comment. The planet would've looked completely different and unrecognizable when we had rings.

I mean technically we have rings now too thanks to Elon Musk and the billions of space trash orbiting the planet. But Earth with rings legit rings was a whole other experience.

and if some mad billionare decides that a planetary ring is what they want,a grand gesture if you will,then the technical challenge is not that big chaff and a delivery/dispersal mechanism launched from an equatorial mountain dispersal is just another burn on a stabil orbit

Nice opening image, but what would the view be like from Earth?

Ron Miller is an artist who made some very nice visualizations. I can’t vouch for the scientific accuracy, but they seem plausible enough to me, and consistent with the images I’ve seen of Saturn’s rings from nearby probes.

https://www.planetary.org/articles/20130626-earths-skies-sat...

Wow, now I'm sad I don't live in that reality.

Rings like that would have been a game changer for early navigation.

I don't know, but I get goosebumps from pictures like these

I love, love, love these. Thanks for sharing.

Off the top of my head, if the rings were a narrow band around the Earth, and were aligned with the terrestrial equator, they would be less visible from high or low latitudes. If they were aligned with the plane of the ecliptic, then they would be visible as a band following the 'zodiac constellations', and thus visible much further North and South.

At night, in the shadow of the Earth, I'd think that they would be dark, perhaps even invisible. Perhaps moonlight would serve to illuminate them, depending on the relative position of the Sun and Moon.

I'd guess they would look most impressive around and dusk. The particle density and albedo would influence whether they would be visible during full daylight. The ring density would affect whether they had sharp edges or simply faded out away from the centre.

Only part of the visible rings would be dark at night. You'd see sunlit parts on both sides of the shaded part.

> Planetary rings may be one of space’s many spectacles, but in our solar system, they’re a dime a dozen. While Saturn’s rings are the brightest and most extensive, Jupiter and Uranus and Neptune have them, too,likely the dwindling remains of shredded asteroids or comets.

Reading "The Ring Makers of Saturn", Dr. Bergrun suggests something very different.

Hmmm, Asteroid 99942 Apophis will get pretty close (~50k kms) when it does its near earth fly by in 2929: https://theskylive.com/apophis-info

Wonder if that's close enough for it to break into pieces? :)

*2029

https://archive.ph/A2ZhJ

May see rings around Earth again.. it's the expected state that space debris settles into after Kessler Syndrome.

Kessler syndrome is inevitable if Elon & Trump get their way, https://www.washingtonexaminer.com/news/2811927/trump-propos...

There isnt nearly enough mass up there in all the foreseeable sat constellations. They need enough collective mass to overcome the extreem orbital inclinations/speeds we use for sats. For a visible ring to form, we would have to send billions of sats into high/slow orbits and then just forget about them for millions of years. Even then, they would likely form into mini moons first before those moons eventually broke up into rings.

I had to laugh thinking that we (or some alien race) might come across a ringed planet only to find its rings are made of orbital space junk from a long-dead species that once flourished on the planet.

This made me consider what sort of orbital archeology would take place. I imagine it would be a gold mine for anyone trying to study that civilization, and attempting to snatch pieces out of orbit would be a huge focus.

hopefully the sight discourages them from leaving their own waste behind

https://en.wikipedia.org/wiki/Roadside_Picnic

I was about to make a snarky comment about starlink. It's getting harder to take a shot of the sky without one of those pesky floaties.

Debris left in orbits below 600 km normally fall back to Earth within several years. The Starlink constellation is at around 350 km and below.

Yeah this. I was 50 miles from civilisation in some mountains in central Asia last year trying to do astrophotography and I had to edit out the flying space trash after!

If you needed rescuing from there, or if a nearby village was affected by a natural disaster, this flying space trash is what's saving lives.

It makes sense for the vast majority of people to prefer that against the slight inconvenience in editing out satellite tracks faced by a tiny tiny community of ground bases astrophotographers.

Low orbit satellites are unnecessary for emergency/comm. Fewer, dimmer, satellites at higher orbits are actually cheaper, but LEO constellations are now subsidized by the military industrial complex (there is other value to be low).

Aren’t you overlooking constraints on transmit power for mobile transmitters being better served my low earth orbit than higher orbits?

They're also overlooking the actual prices of GEO satellites versus LEO. LEO is much cheaper than GEO, there's a reason DOD and others are moving towards it and it's not that it's a fad. GEO has a few specific benefits but cost is not one of them.

great point; agreed

> Fewer, dimmer, satellites at higher orbits are actually cheaper

GEO satellites are pretty pricey. Each Milstar satellite cost $800 million, others in the same category are also in the hundreds of millions, WGS-11 was over $600 million. Starlink V2 cost $800k per satellite.

And if you spent $800 million on a constellation of 1000 Starlinks, you'd have better coverage and bandwidth than the entire 6 satellite Milstar constellation put together for 1/6th the price.

Digging around for more recent prices, GEO is around $100-300 million. That's still orders of magnitude more per satellite than LEO. At the low end this means you could get 100-400 Starlink V2s up there for the price of one GEO. One GEO that only covers part of the globe, versus 100-400 satellites providing global coverage.

It's crazy how unnecessary things can be trillion dollar industries :)

yeah like carbon credits

Satellites have to pass through the Van Allen belts in order to get into such higher orbits, which may expose them to a not insignificant amount of radiation, especially if the final orbit injection is not done in a single impulse. Then, once they are comfortably out in their higher orbit, they have to endure yet more radiation without the aid of the Earth's magnetic field, and require more cooling capacity due to spending much less time in Earth's shadow than an LEO satellite.

No it's really not. Please don't think suburban USA can be extrapolated to the middle of bloody nowhere.

I might be able to get a message off, but how the hell do you contact the emergency services and who the hell is going to rescue me in a country with one rescue helicopter that was out of action at the time?

In circumstances like that it's better to actually get some mountain safety training, have some procedures and other comms equipment in place. And importantly travel in a group with the right equipment (including 4 legged transport devices).

As for the astrophotography that was opportunistic.

I'm subscribed to Garmin SAR that uses Iridium sats. When you signal an emergency, they contact the local rescue agencies.

And while they might not send a helicopter, a team if rescuers on foot can still help in most cases.

I have an InReach Mini 2. It is not necessarily useful. It depends on where you are. Don't make any assumptions about it until you've done research.

You'll find some places have only voluntary services and the phone is likely only manned on week days on limited hours. If you're lucky there might be a gmail address you can hit. No joke.

It might not be useful in Afghanistan or Somalia, but it has a pretty wide coverage. Even if it's a niche product.

Once satellite communication is truly accessible to everyone, I expect other companies to compete in this area.

They low orbit satellites are only visible while they're in sunlight near sunrise/sunset.

I read that those things' orbits degrade in like five years tops. So at steady state, for a constellation of size N, you need to launch N/5 of them each year, with the attendant fuel burn. Seems like that kind of pollution is a bigger long term worry than the short-lived junk? On the other hand, until it does fall down, I suppose it's a risk to anyone who wants to launch up through it.

They are like the size of a coach and the distance between them is is about 550km or 342 miles aproximatly one Washington state wide, avoiding hitting them shouldn't be that hard. You would have to try to hit them. Space is big.

Sustainable space exploration is needed

Wouldn't all LEO stuff just de-orbit and burn eventually?

The ring of Uranus. One of the wonders of the solar system.

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