View Full Version : Smoke Ring

2009-May-26, 02:22 AM
Could something like the gas torus from Larry Niven's The Integral Trees actually form?

If so, with current technology, how far away could we detect such a thing?

2009-May-26, 06:21 AM
' skepticj.' ; Help me understand your question. I have not read Larry Niven's books. Could you explain a little more.?

grant hutchison
2009-May-26, 09:26 AM
A gas torus, formed by gas escaping from the satellite of a larger body, but unable to escape the gravity of the larger body itself: it therefore hangs around in a ring along the satellite's orbit.
There are examples in our own solar system, formed by satellites of Jupiter and Saturn, but very tenuous.
Niven made his much denser, by having it form from a gas giant in orbit around a neutron star. The gas mixture was breathable, and dense enough to support life in its central part.

Grant Hutchison

2009-May-27, 07:59 AM
There are examples in our own solar system, formed by satellites of Jupiter and Saturn, but very tenuous.

Io and Enceladus?

2009-May-27, 09:53 AM
Io and Enceladus?

Saturn's rings have a tenuous oxygen atmosphere as well.

I don't think there are any serious problems with the concept (as there are with, for a totally random example, a ringworld without active stabilization), but it would be extremely unlikely to ever form. I suspect they'd be reasonably attention-grabbing from the bright fluorescence of the dense oxygen-atmosphere torus stimulated by the hard UV from the neutron star.

grant hutchison
2009-May-27, 05:42 PM
Io and Enceladus?And Europa and Titan.

Grant Hutchison

2009-May-29, 06:16 PM
That's absurd! As we all know, rings in outer space are unstable! (http://en.wikipedia.org/wiki/File:PIA07712_-_F_ring_animation.gif)

On a more serious note... It's been proven that toroids void of external gravity are unstable, and that solid toroids in an external gravity field are unable to maintain a proper orbit. A toroidal-like ring composed of individual particles, however, such as Saturn's rings, is stable.

My question concerns the stability of a ring of sufficient mass such that it's localized gravitational self-interaction overpowered the gravitational influence of the larger body around which it oribited. Wouldn't it destabilize into pockets of matter due to the Roche limit, and thus fail to maintain a true toroidal shape?

2009-Jun-01, 01:29 AM
For those who never read "Smoke Ring" -- the eponymous gas torus is indeed constantly replenished from a gas giant planet on a two-hour orbit around a neutron star. It is similar to Io torus around Jupiter, but is vastly denser -- the pressure in torus' midline is about 1 atmosphere. May actually be possible, given that escape velocity from neutron star orbit is many times greater than molecules' velocities. As a molecule bounces out of the Smoke Ring, its ballistic trajectory brings it back in. No different, really, from why Earth's atmosphere does not just "float away" -- but on a vastly larger scale.

One problem I have, is does a gas giant actually have enough gas to fill up the volume of Smoke Ring? Can someone check the radius of a two-hour orbit around a body with 1.4 solar masses?

2009-Jun-08, 04:40 AM
"Gas giant" is a pretty broad category. A gas giant on the fuzzy bottom limit of being a brown dwarf...

What I wonder is if that much oxygen gets together into one planet. It's the third most common element in the universe, yet it doesn't make up that much of gas giants (at least in this system).

2009-Jun-08, 06:19 AM
An oxygen 'smoke ring' is very unlikely, since oxygen tends to bond tightly with other elements. A hydrogen 'smoke ring is a little more likely, so perhaps you might find them occasionally out there in the universe - but surely the density of the atmosphere in such a ring would be very low. The few examples in our solar system are practically hard vacuum.

Perhaps you might find hydrogen-breathing life in such a ring; the life wouldn't need to be bouyant, as it would in a gas giant atmosphere, so the environment might be slightly more hospitable than inside a jovian-type world.

Maybe an oxygen-rich ring could be formed by photolysis of a water ring, and subsequent escape of the hydrogen (hey - is that how Niven described the Smoke Ring? I can't remember, to be honest). Otherwise maybe a 'smoke ring' might form from material stripped from a waterworld. Waterwoulds might sometimes have oxygen-rich atmospheres, formed by photolysis.

Life in a smoke ring has to be careful not to wander into low-pressure areas. There is a tendency for particles in a smoke ring to move back toward the midline (otherwise they'd wander off) - but this might not be fast enough to prevent inhabitants of a ring from suffocating in the process. Presumably any indigenous life of such a ring would have fins or wings of some sort for just such an emergency.

2009-Jun-09, 12:13 AM
At orbital speeds the drag would be enormous, then every two hours a planet smashes into you! Absurd plot, surely?

Bearded One
2009-Jun-09, 02:14 AM
At orbital speeds the drag would be enormous, then every two hours a planet smashes into you! Absurd plot, surely?The whole mess is in orbit. Moving around in it does require an understanding of orbital dynamics, which is why the occupants developed sayings to aid in remembering. Moving along ahead in the orbit takes you out, moving back along the orbit takes you in. I forget the exact wording they used.

Locally it pretty much acted as if everything was just floating around in free fall. In fact, it was floating around in free fall. The novel had long tree like structures that grew radially out from the center. These structures developed tidal forces at the top and bottom allowing life with some semblance of gravity.

2009-Jun-09, 09:15 PM
east takes you out, out takes you west, west takes you in, in takes you east.

And east/west vs. in/out might be reversed.

East and west were respectively, I think, co-orbital and anti-orbital.

Out and in were in relation to the central neutron star.