If Earth had rings, like Saturn, would we have constant problems with pieces of the ring falling down to the planet and causing catastrophic damage?
Unlikely. The vast majority of the particles in Saturn’s rings are itty-bitty. Not big enough to cause anything more than pretty steaks in the sky. Anything big enough to cause lots of damage would probably be in a stable orbit.
No. Material in a circular orbit (which rings are by definition) doesn’t just fall down randomly, and rings in particular are are pretty finely graduated material that would be vaporized by aeroelastic heating (colloquially “burning up”) even if they were somehow knocked out of orbit, notwithstanding that Saturn’s rings are almost entirely composed of water ice.
Forming rings that will remain stable and differentiated for any period of time requires multiple smaller moons creating stable resonance conditions. Earth with its single large Moon (relative to the size of the primary) would quickly disrupt a ring system due to tidal perturbations.
Stranger
Sounds beautiful, and delicious.
Maybe. There have been some studies that indicate the Earth might have had a ring system about 450 million years ago. As @Stranger_On_A_Train said, having stable rings requires “shepherd moons”, smaller moons that create stable conditions and keep the rings in place. Otherwise the ring isn’t stable and will eventually disappear.
The Earth is too close to the Sun to have ice rings like Saturn does (they’d essentially melt and sublime away into nothingness). But it could have rock rings. The theory is that the Earth captured and pulverized an asteroid about 450 million years ago. This may have caused a lot of the global cooling that happened around that time, and unstable chunks falling out of orbit may have caused quite a few impact craters as well. Researchers found a bunch of craters from around that time that were all relatively close to the equator, like you’d get if there was a ring with unstable asteroid chunks in it.
The rings wouldn’t be stable in the long run (as you can see, if we had any they are gone now), but they would probably last for many lifetimes. A short time for cosmic scales is a rather long time at human lifespan scales.
Yes.
The problem is they’re all well done by the time they get to the plate.
Is there a limit, given tidal forces, for the size of a ring element vs its altitude? Assuming a long term stable orbit.
The rings wouldn’t just fall down onto the surface, but they would be a major obstacle to spaceflight, essentially our existing space debris problem on a much more intense scale. For Saturn, they’re mostly in the equatorial plane, and at altitudes that include Saturn’s equivalent of a geostationary orbit (where the orbital period equals the period of the planet’s own rotation). If we had the same situation on Earth, the geostationary orbit, which is a valuable location for telecommunications and other satellites, would be essentially unusable. I suppose there are other objects, not neatly arranged in striking rings, in other orbital planes around Saturn too, so if we had this on Earth then anything we launch from our planet in whatever direction would have to punch through a region that exposes it to a serious risk of collision.
But it’s fascinating to think up the counterfactual of Earth’s civilisation if it had always been surrounded by a ring system. For sure these rings would feature prominently in mythology and legends.
Tidal forces are the thing that breaks up satellites into smaller chunks (which may then form rings) if their orbit is too low:
Mascons are the thing that cause problems with stable orbits:
Dropped from orbit, tumbling through air, a steak from space gets an intense sear there. As Randall Munroe’s “What If?” explains, the outer layer chars, then flakes like grains. Hypersonic heat blasts and strips it bare, leaving it raw inside: “Pittsburgh rare.”
I doubt it. The large majority would be in a stable orbit, and the occasional fragment that did enter the earth’s atmosphere would burn up in a large majority of cases. Keep in mind that the earth is bombarded by meteoroids, but we hardly notice it because they burn up in the atmosphere. NASA states: “Every day, Earth is bombarded with more than 100 tons of dust and sand-sized particles.”
Just a side note - the USSR came up with a quasi-permanent satellite system that served northern regions. they put satellites in a 12-hour orbit highly inclined. The satellite lingered during Apogee at the top of its orbit, high in the sky from a northern latitude. In the OP’s ring situation, the perigee would be inside the ring system. Since this only served for a short time, they planned multiple satellites whose orbits formed a flower shape, where a satellite lingered near the top of the “petal” until the earth turns a bit and a different satellite is in that general area of the sky.
Obviously nowhere near as useful as the current geostationary setup where there are satellites evey few degrees.
No wonder no one ever describes what they recovered from the seven Columbia astronauts! Oh my!
Nice video, but note you have to reset it to the beginning.
There are far more than “satellites evey few degrees”; as of February 2024 there are 562 satellites in GSO and quasi-GSO orbits.
Stranger
Yes, you can also make geosttionary satellites slightly non-stationary, so they appear to describe a circle in the sky over a certain point. The limiting factors appear to be quality of dish aim and the ability of the dish LNA to separate one signal point from another. (And frequency allocation, satellite antenna aim, etc.)
That is giving the satellite’s orbit a bit of inclination. But they don’t make a circle, but rather a figure 8. With respect to the ground, of course.
IIRC making the orbit slightly elliptical (but still with 24-hour orbit) will make it appear to do a circle or ellipse…