Question:
Why does Saturn have its rings in a disc as opposed to a random
arrangement around the planet? Also why does the disc have rings or ringlets as
opposed to a continuous uniform disc? Are these rings travelling at different
speed and are they all travelling in the same direction? Thanks
Replies:
The reason for the disk is probably because most of Saturn's other
satellites orbit in roughly the same plane - this is common in satellite systems
- for example all the planets orbit the sun in roughly the same plane, so if you
traced them out they would form rings in a disk too. The rings are actually made up of billions of
small particles (chunks of ice mostly) that are orbiting the planet. The reason
there are all these small particles (forming an almost continuous disk) is that
when you get too close to a big planet, tidal forces cause a satellite to break up into tiny
pieces. So these rings probably represent the destruction of some old bigger
moons (or perhaps they're just left over from the original formation of Saturn).
The reason for the rings or ringlets seems to be because the orbits of these
chunks of ice are affected by some so-called "shepherd" moons that are still in
one piece orbiting in the ring region.
This was a big question a few years ago when the first Voyager pictures came
back - maybe somebody who knows more can tell us the latest story on this?
The rings are indeed all traveling in the same direction - otherwise you would
get some rather nasty collisions eliminating things going the wrong way. They
orbit at different speeds, though, because the farther out they are away from
the planet the slower they need to go to stay in orbit.
NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.
