Saturn - Dressed to the Nines


note flattening

Key Points


  • diameter 9 x > Earth (~120,000 km vs ~14,000 km)
  • mass 95 x > Earth

Distance from Sun

  • 9.5x further than Earth


  • ~29 years

  • 10.5 hours
  • bulges at equator, flatted on top
  • 10% slower at high latitudes


  • ~92% H2, ~7.5% He, ~.2%CH4
  • rem Jupiter ~86%H2, 15% He
  • Because of this composition Saturn would float
  • Has belts and zones (like Jupiter) but they are not as noticeable



 The Rings

 Roche limit -
  • inside this gravity (tidal forces) pulls things apart - the force of gravity is higher between the larger body than between the individual particles
  • It's ~2.5x the radius of the larger body - so the rings are most likely to be a satellite that failed to accrete
  • Does the Sun have a Roche Limit?

Ring rotation is measured by doppler shift

Composition is most likely water ice


Major Ring Divisions A, B, C as seen from Earth

A is outside ring it is separated from the B ring (brightest) by a space

Cassini's division


shepherd moons


100s of thousands of rings w/ a constantly changing structure



  • particles about the rings possibly head in place by electrostatic forces
  • occultation of a star shows that the spokes are about10-6 m. in size (dust particles in sunlight)
  • another victory for non-optical sensing (50x better resolution)
total mass - ~midsize satellite (Mimas)

Pioneer (1979) vs Voyager 1(1980) 100x data transmission capabilities




Impact crater

Titan - THE BIG ONE!?

  • thick atm.(1.5x Earth) mostly methane (organic)
  • remove atm. just smaller than Ganymede, but bigger than Mercury,
  • so it lost its position of biggest satellite (residents are happy as it cuts down on the number of tourists who come for the view)