Tilted Forum Project Discussion Community - View Single Post - What would Earth be like with Saturn's Rings?

Martian · 12-18-2009, 04:11 PM

There's a considerable body of evidence that points to the idea that the Earth did have a ring system fairly early in it's lifespan.

Planetary rings are a fairly common phenomenon, as noted in our own solar system (4 of 8 planets are known to have them). The general consensus, however, is that they're not stable and will dissipate over time. The timeframe on that is typically thousands or millions of years, but the presence of other bodies can lengthen that considerably. The gas giants all have multiple satellites that help to keep the ring systems coherent.

A planetary ring is thought to form in one of two ways. Planets themselves are formed from accretion discs (also known in this context as protoplanetary discs) which contain stellar dust and particulates; over time, gravity causes all of the 'stuff' to clump together and form into a planet. Matter outside the planet's roche limit but within the planet's gravity well may coalesce into a moon -- this was once thought to be how our moon came to be, but has been deprecated in favour of the impact hypothesis in recent times. Anything within the roche limit, however, will fail to coalesce due to the high gravity of the planet itself. This results in a ring.

The other scenario for planetary rings is that an object may fall within a planet's roche limit and enter an orbit there. If that were to happen, tidal forces would tear the object apart, again resulting in a ring.

The Earth may have had a ring formed from leftover debris very early in it's life, possibly even predating the Moon. However, with nothing to keep the ring in place it gradually dissipated. For those who want a new ring system, take heart; it's hypothetically possible that the Moon's orbit will one day destabilize, causing it to fall within the planet's roche limit and be transformed into a planetary ring. In a few billion years, you may get what you want.

I think it goes without saying that a planetary ring suddenly appearing around the Earth would be rather catastrophic. No need to worry, though. That's nearly impossible, and we're far more likely to be wiped out by a meteor before such a thing could ever happen.

12-18-2009, 04:11 PM	#19 (permalink)
Martian Young Crumudgeon Location: Canada	There's a considerable body of evidence that points to the idea that the Earth did have a ring system fairly early in it's lifespan. Planetary rings are a fairly common phenomenon, as noted in our own solar system (4 of 8 planets are known to have them). The general consensus, however, is that they're not stable and will dissipate over time. The timeframe on that is typically thousands or millions of years, but the presence of other bodies can lengthen that considerably. The gas giants all have multiple satellites that help to keep the ring systems coherent. A planetary ring is thought to form in one of two ways. Planets themselves are formed from accretion discs (also known in this context as protoplanetary discs) which contain stellar dust and particulates; over time, gravity causes all of the 'stuff' to clump together and form into a planet. Matter outside the planet's roche limit but within the planet's gravity well may coalesce into a moon -- this was once thought to be how our moon came to be, but has been deprecated in favour of the impact hypothesis in recent times. Anything within the roche limit, however, will fail to coalesce due to the high gravity of the planet itself. This results in a ring. The other scenario for planetary rings is that an object may fall within a planet's roche limit and enter an orbit there. If that were to happen, tidal forces would tear the object apart, again resulting in a ring. The Earth may have had a ring formed from leftover debris very early in it's life, possibly even predating the Moon. However, with nothing to keep the ring in place it gradually dissipated. For those who want a new ring system, take heart; it's hypothetically possible that the Moon's orbit will one day destabilize, causing it to fall within the planet's roche limit and be transformed into a planetary ring. In a few billion years, you may get what you want. I think it goes without saying that a planetary ring suddenly appearing around the Earth would be rather catastrophic. No need to worry, though. That's nearly impossible, and we're far more likely to be wiped out by a meteor before such a thing could ever happen. __________________ I wake up in the morning more tired than before I slept I get through cryin' and I'm sadder than before I wept I get through thinkin' now, and the thoughts have left my head I get through speakin' and I can't remember, not a word that I said - Ben Harper, Show Me A Little Shame