outer planets and rings

Status
Not open for further replies.
B

buckeye101

Guest
How come the four outer planets all have rings but the inner four do not?
 
F

fragrance

Guest
I hear a theory from a TV teaching programme, and it says that at first our earth also had a ring, but later it got together and formed our moon. I am not sure weather it is ture or not, may be it is just a theory.
 
S

search

Guest
Here is a quick and simple explanation (author in the bottom):<br /><br />"It turns out that all of the planets, Earth included, did have rings at one time. The thing is, these rings were unstable and the material was either lost to space or collected into the satellites of these planets. The difference between the terrestrial and giant planets is the giant planets have the gravity to capture and hold onto a large satellite system, and these satellite systems are the source of the ring material. <br /><br />For a ring to be stable, it must be held tightly by the planet's gravity, and the planet must also exert tidal forces on the particles in the ring. Tidal forces result from the fact that the pull of gravity is inversely related to distance, so the farther away an object is, the less force it experiences from the object it is orbiting. Therefore, a planet pulls a little bit more on the inner side of its moons than on the outer side. Close enough to a planet, this might cause a moon to break apart, and also keeps the bits of material that form a ring from collecting together into a moon. <br /><br />However, it's possible that Mars might develop a ring in the future. Its moon, Phobos, is close enough to the planet that it feels the effects of the planet's tidal forces, and eventually it may break apart and form a ring. <br /><br />Earth, Mercury, Venus and Pluto will probably never again have observable rings, although if you dumped tons and tons and tons of sand near the planet, it would probably form a ring - pretty cool eh?" <br /><br />February 2003, Cathy Jordan (more by Cathy Jordan), Matija Cuk (more by Matija Cuk)<br /><br />
 
H

harmonicaman

Guest
The Solar Wind contributes a constant force which strips inner planets of their gaseous atmosphere and likely prevents fine particles from forming rings. Planets located far enough away from the Sun's influence likely don't have this problem.<br /><br />
 
C

CalliArcale

Guest
Quantity of moons is probably also a factor. Rings tend to be unstable, so either they are young, or something is replenishing them. In the case of Jupiter's very tenuous system of dust rings, it is the volcanoes of Io that do the job. These volcanoes in turn exist solely because of Io's position as the innermost of the Galilean satellites -- it is heavily strained by tidal forces. No one knows for sure what supplied the material for the rings of Saturn, Uranus, and Neptune. The best studied of these are Saturn's rings. In fact, Saturn's rings are a major target for the Cassini mission in their own right. They are mostly made of ice, with varying particle size and varying amounts of rocky material. This is similar to the composition of Saturn's moons, so it is widely speculated that Saturn's glorious rings (by far the most spectacular of the ring systems) are the debris from one or more collisions between natural satellites of Saturn. Saturn does have a fantastically busy system, with complex gravitational interactions and abundant evidence of very heavy bombardment on all but the most geologically active of the moons (Titan and Enceladus). So the idea is very appealing. But is this idea true? And what created the rings of Uranus and Neptune? Unlike Jupiter's Io-fed ring, it's not easy to tell. We're ultimately left with speculation. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>
 
E

eagledare

Guest
We do not know - YET - there are theories but dust and particals collecting toggether in space seems to be an outgoing theory. why does the objects in the Kuiper belt and the ring between Mars and Jupitor not attract each other to form a planet? There are many questions still to be answered and each time we find one ten others pop out of that one.
 
S

Saiph

Guest
well, in the asteroid belt they don't clump together because of jupiter's influence keeps stirring them up (look up kirkwood gaps).<br /><br />For the kupier belt, I'm not so sure, it's likely to do with the huge orbital periods and the perturbations from nearby stars (kupier belt is beginning to be in that range). <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>
 
M

MeteorWayne

Guest
Plus the generally large distance between individual asteroids. The popular vision of the asteroid belt (the one between Mars and Jupiter) shows swarms of asteroids visible next to each other. The reality is you would only rarely be able to see one asteroid from another.<br />In the K-E belt it would be only more sparse.<br />MW <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
H

halcyondays

Guest
Indeed. We have now sent a large number of spacecraft through the asteroid belt, and none has come amiss.
 
Status
Not open for further replies.

Latest posts