1. Essential Question
What do we know about the ring systems of the gas giants in our solar system

2. What do we know about the ring systems of the gas giants in our solar system
All of the gas giants have many moons and are surrounded by a set of rings. A ring is a thin disc of small particles of ice and rock.
RINGS
MULTIPLE MOONS

3. THE RING SYSTEMS OF THE JOVIAN PLANETS
What do we know about the ring systems of the gas giants in our solar system
THE RING SYSTEMS OF THE JOVIAN PLANETS
Each of the four jovian planets has a ring system. But, the rings for each planet are very different!
"Why haven't the rings formed a moon?"
Roche Distance -- This is the distance at which the tidal forces on a object are stronger than the gravitational force holding the object together. (The difference between the gravitational pull of the planet on the near side and far side of a moon is greater than the gravitational force of the moon itself).
Typically, the Roche distance is 2.5 times the radius of the planet. So, moons that come closer than the Roche distance will be torn apart!

4. What do we know about the ring systems of the gas giants in our solar system
  Jupiter's rings come directly from its moons, and are outside its Roche Limit.  For Uranus and Saturn the rings are within the Roche Limit, and may be tidally disrupted bodies, although surprisingly small.  The situation for Neptune is not so clear. 

5. The Rings of Jupiter
 These rings were discovered in Not easily observed like the rings of Saturn. An Infra-red picture.
The diameter is not much greater than Jupiter. Very close to Jupiter, so particles spiral in.
These rings are made of small dust particles.
Source of these particles:
1) Pieces of meteorites falling into Jupiter. 2) Ejecta from the volcanos on Io.

7. Saturn has rings around it that are made of chunks of ice and rock, each traveling in its own orbit around Saturn. Saturn has the most spectacular rings of any planet. Saturn’s rings are broad and thin, like a CD.

8. These rings are made of water ice.
The Ring System of Saturn
The diameter is about 200,000 kilometers. The thickness is only about 20 meters!! An edge-on view.
Rings are not solid, the inner parts of the rings revolve around Saturn faster than the outer rings.
These rings are made of water ice.
Probably pieces of rock covered by ice.
Mostly small in size, ranging from 1 cm to 10 meters.
Rings are a very complex system!
Wide range of compositions, many "gaps", transient "spokes" occur.
Are rings young or old? ?????

9. What do we know about the ring systems of the gas giants in our solar system
Uranus is about 4 times the diameter of Earth, but is still much smaller than Jupiter and Saturn. Uranus is a very far from the sun, making it colder than Saturn, and is surrounded by a group of thin, flat rings that are much darker than Saturn’s rings.

10. What do we know about the ring systems of the gas giants in our solar system
This is an infrared image of Uranus, its rings and moons,  taken by the Hubble Space Telescope.

11. The Uranian Ring System
Discovered in 1977 during a stellar occultation.
There are 10 separate rings, with a width between 10 and 100 kilometers.
Ring particles are "large", meters in size.
These particles are dark, not made of water ice.
Space between the rings is filled in by dust particles.
Shepard" satellites keep these rings thin!
What do we know about the ring systems of the gas giants in our solar system

12. The Rings of Neptune
Evidence observed in mid-1980s during a stellar occultations.
Occultation suggested "arcs" rather than rings.
Existence confirmed in 1989 by Voyager 2.
There are 6 separate rings, less than 100 kilometers width.
Ring particles are very small and dark, not water ice.
Outer ring has 3 clumps of material.

13. Ring Related Links of Interest
The Small Satellites and Rings of Jupiter.
Terrestrial Planets
Outer Moons and Icy Bodies