If the planets and moons were formed by dust and rocks clumping together...?

Question

....why is it that the dust and rocks that make up Saturn's rings, the Kuiper belt and Oort cloud don't behave in the same way?

Why don't they clump together to form another single body?

I expect the answer is extremely obvious, but it's a genuine question.

Thanks

Yes Lauren - that's why we were wondering why the small ones aren't attracted to each other and clump together.

Thanks, Martin. That makes sense.

And you, Rowdy.

Answer 1

I don't think our knowledge of how the solar system formed is good enough to say that the answer to your question is obvious. But some of it has to do with the gravitational influence of other bodies. The formation of large planets such as Jupiter makes it harder for other planets to form, because the small rocks are now more influenced by the gravitational force of these other planets than by each other.

Saturn's rings may be a different case from the others because modeling suggests they are much younger than the planets. The rings are thought to have formed from the debris of moons that broke up from collisions or from being pulled apart by Saturn's gravity. For the most part, the gravitational influence of Saturn and its moons will prevent the rings from clumping together, but there may be places within the rings where the moons' gravity causes clumping, and perhaps another moon will be formed.

There are some fair-sized Kuiper Belt objects (e.g. Pluto, Sedna, and Eris, if it can be considered as belonging to the Belt). We don't have a clue what's going on in the Oort cloud. Its existence is mainly conjecture at this point. Some of what we don't know about the outer solar system is whether the objects formed out there, or formed closer in and were later forced into more distant orbits.

Answer 2

The previous Answers are all good and proper, but they all miss one important detail. Saturn isn't the only planet to have rings, Jupiter, Uranus and Neptune also have rings although not as spectacular as Saturn's ring system.

Lets Brake your question down and start with the formation of the solar system. The Sun and planets formed from a flattened cloud of interstellar material. Clouds of interstellar material have been observed throughout the universe. These clouds spin, causing them to flatten along their rotational axis. This accounts for the planets forming in the same plane. Gravity also causes the cloud to collapse. During this process, the center contracts into a ball of hot gas and dust. This will become the sun; in this stage it is called a protosun.

The next process is accretion, which results in planet formation. First, the gases outside of the sun condense into solid materials. These particles collide forming larger particles called planetesimals, which in turn collide and form protoplanets. These protoplanets then become planets. The composition of the planets is a result of the order of the solid materials that formed from the gases outside of the sun. The jovian planets are large, with high gravitational fields, so they accumulated much of the Hydrogen and Helium.

Now for Ring formation


Ring Structure
Saturn's ring system is divided up into 7 major divisions with alphabetic designators in the order of discovery. From the innermost ring to the outermost ring the designators are D, C, B, A, F, G and E. Each major division is further subdivided into thousands of individual ringlets. The F and G rings are very thin and difficult to see while the A, B, and C rings are broad and quite visible. Between the A and B rings is a gap called the Cassini division named after Giovanni Cassini who discovered the Gap in 1676. Between the A and F rings lies the Keeler (Encke) gap.


Saturn's braided F-Ring.
Much of the elaborate structure of the rings is due to gravitational effects of nearby satellites. This phenomenon is demonstrated by the relationship between the F-ring and two small moons Prometheus and Pandora that shepherd the ring material. The F-ring shows a complex structure made up of two narrow, braided, bright rings along which "knots" are visible. Scientists speculate that the knots may be clumps of ring material, or mini moons.
In the mid 1980s Dr. Jeff Cuzzi noticed a wavy pattern in the ring material on both sides of the Encke gap. It was suggested that an unseen asteroid-sized moon in the gap caused the disturbance. Dr. Mark Showalter further analyzed the disturbance and used this "moonlet wake" pattern that resembled a motorboat wake, to determine the position and mass of the unseen body. The amplitude of the waves, he said suggested the mass of the unobserved object and the wavelength of the ripples revealed the moon's possible position. Using this mathematical model, Dr. Showalter was able to predict which Voyager images the moon would be in. In 1990 Dr. Showalter's work paid off and Pan was discovered within the Encke gap.

I hope that this answers your question

best wishes

Matt

Answer 3

The rings of the gas giant planets are believed to be debris from destroyed moons and comets. this breaks down over time and apart from Saturn most planets rings are very sparse. Saturns rings will fade over time as the matter is caught by the gravity of the planet and it's satelites.

The matter of the Kuiper belt hasn't sufficient density for a single object to form that would be capable of attracting the rest of the matter. In the inner solar system planets "hoovered up" the dust and rock in their orbits. "Xena" is I think the largest of the Kuiper belt objects but the mass is still too small to draw in that much of the other objects.

Answer 4

The forces that came into play,when the rocky debris,from the super nova that created us,crashed into the hydrogen field that makes up our solar system,were so diverse that about any configuration for a solar system was possible.
Obviously the earth was an accumulation of this debris.
Other accumulations were shattered by collisions.
Some accumulated in loose bundles never forming a substantial body. Some went into ringed orbit,like the rings of Saturn.
If a field of rocky dust started to accumulate,the gravity would increase,these loose dust balls,as they grew,would be compacted by gravity forming a massive solid body.
Earth probably started in this way.
It"s possible to go on and on but I am sure you get the picture.

Answer 5

In the case of Saturns rings, they don't clump together because they are too close to the planet. Accoarding to Newtons laws the closer an object is to the planet the faster it will move. The particles that make up the rings are moving very fast (about 20 km/sec.) Although the particles are moving much slower relative to one another, they are still moving too fast to have time to stick together. The moons are further away from the rings in regions where the particles are moving more slowly.

Answer 6

In fact that can be answered by two ways.

All matter was born during big bang, there was no preference of size, it's just a probabilistic result that they are what they are now.

This arises another question, why they are not forming a single body.

To form a single body, every atom of the dust and rock (i.e. matter) must overcome the coulomb force between them and come close enough to join as a single piece. There gravitational attraction is not enough for that.

But inside a "forming cluster", the gravity is large enough to collect such things, and give birth to a star.

Also it may be, that they were originally a single object, later crushed to pieces by a catastrophe.

Answer 7

Size is a big reason. Saturn is 95 times more massive than Earth and thus boasts more moons and more gravitational pull, both of which are vital to ring formation. Moons, in particular, are the critical factor in the creation of Saturn's "dust rings". The icy "classic rings," which are the ones depicted in the Cassini images, are a bit more of a mystery, however.

The dust rings, composed of trillions of micron-sized specks, are almost certainly composed of debris from Saturn's 31 moons. When asteroids and other objects collide with these moons, tremendous amounts of dust are discharged and trapped in Saturn's orbit, forming rings.

Answer 8

They may have been a part of a single large body that had been destroyed by another large body. They may end up clumping together if they didn't have a common orbit around the sun and/or planet. It's like snow -- it doesn't clump when it all falls together. It only clumps when it gets rolled.

Answer 9

Rhubarb, everyone is wrong, its all a flie that the planets were made from dust., as can be seem by Jupiter's rings, they haven't formed a new moon.
Its simple, think of all the moons, planets and other heavenly bodies as snooker balls, they were all sitting in a corner of the universe, minding there own business, when god came along and thought, you know what? I want to have some fun with these planets that I have made, so he got his giant snooker cue, and whacked the planets about, where they all are now is complete random.
This is how it happened

Answer 10

Hello,

(ANS) It is my understanding that in the case of Saturn the dust & ice and rock particles that form the rings. The rings are formed because saturn has a different shaped magnetic field than that of the earth, this has an effect on the gravitational field surrounding saturn. The rings are held in this single plane because of the magnetic field & gravitational effect. As well as other factors like the actual rotation of saturn itself.

**Free floating material in space i.e. dust & rock only tend to form a single autonimous body like a planet when there is enough of a gravitational effect, to pull in material towards itself. Its all a question of magnetic fields & the strength of local gravity. In fact this is how the earth was formed according to the latest theories in cosmology.

But you have to understand that we are talking incediblely long time scales here, its estimated that the universe & big bang took place 200billion years ago & that earth itself was thought to be formed only 60 to 70 billion years ago. Its thought our entire universe only has another 200billion years remaining before our own star runs out of its nuclear fuel and starts to die.

IR