saturn

1 Saturn & moons Cronos or "Father Time" Hendrik Carré (1735) [symbolism of Saturn & cycloidal arcs refers to Huygens - Boerhaave 8/94] 2 ?Saturn Devours his own Son? - Goya (1819) Uranus, God of the Heavens + Gaia, Goddess of Earth 12 titans, including: Cronus = Saturn, who castrated Dad then Cronus + Rhea more titans, including Poseidon = glyph1197eptune and Zeus = Jupiter, who avoided being swallowed by Dad (who was nervous about rebellions) and eventually overthrew Dad and became King of the Hill Greek mythology 3 Saturn passes in front of the Crab Nebula! (2003) Chaco Canyon (New Mexico) - 11th c. pictograph 4 (semi-real) (another type of eclipse) Keck infrared (17 micron) VLA radio (2 cm) 5 As for Jupiter: aurorae imply energetic particles in a magnetic field Properties of Saturn Orbit: 10 AU Day = 11 Earth-hours Year = 30 Earth-years Diameter = 9 Earth-diam = 0.8 Jupiter-diam Mass = 100 Earth-mass = 0.3 Jupiter-mass Mean density = 0.7 gram/cm3 Temperature (cloud-tops) = 90 K = -180° C Has magnetic field and energetic particles belt Atmosphere Pressure: as much as you want! Composition: next slide 6 Composition of the two big guys (%?s by mass) 7 Spacecraft Cassini?s view of Saturn and its rings 8 Rings edge-on + 2 moons! (Chris Butler, 2003) 9 Saturn?s ring particles (W. K. Hartmann) - few cm to 10 m in size, with a very few biggees; total mass equivalent only to a single moon of ~100 km diameter - ?clean? ice (relative to a comet?s dirty ice) - typical separation of particles ~5-10 times their size; several ?layers? thick; total ring thickness only ~10-100 m! - age ~200-400 Myr? a ?recent? catastrophic event? - or as old as the solar system and they?ve been kept clean by XXX? ?Shepherd? moons 10 Pan shepherds a gap in the rings Saturn has its own menagerie of moons 11 Phoebe Tethys Iapetus 12 Iapetus -an old surface, with trailing side much brighter than leading side 8-km high equatorial ridge Dinky moons of Saturn 13 Mimas, the Death Star moon (crater = Herschel) Mimas 14 Enceladus 15 Geysers of water vapor! (Cassini mission, 2005) 1.6 g/cm3 = mean density - Does its resonance with another moon cause enough tidal heating to make a water ocean? 16 Titan, Saturn?s biggee (Voyager ~1980) Jean-Dominique Cassini (I) Christiaan Huygens 17 Cassini spacecraft The new Titan 18 Infrared imagery of Titan Large impact crater - note runoff channels on outside 19 Radar image showing dunes (?cat scratches?) (hydrocarbon sediments?) (300 km from top-to-bottom) Compare dunes on Titan vs Earth sand on Earth (radar) not sand! 20 Composition of the two big guys (by mass) Mapping of surface by radar reflectivity 21 Liquid methane lakes on Titan This is a map of radar reflectivity, colored (very) suggestively A Titanian lake (sea?) versus Lake Superior, Michigan 22 http://www.astro.washington.edu/smith/Astro150/ Titan landing movie Huygens probe coming in to land Jan. 2005 23 Comin? in Saturn?s moon Titan Drainage channels Methane rivers?! Huygens lander 2005 24 January 2005 landing of Huygens probe Actual image drawing Phase diagram for methane = CH4 Titan?s atmospheric pressure and temperature are such that methane can be gas, liquid or solid gas liquid solid 25 ?Methanology? (vs Earth?s hydrology) CH4 methane [ Hydrocarbons (?fuels?) ] ?.But mostly glyph11972 - how can it hold on to so much atm despite its small gravity?! 26 Solar UV drives the chemistry Stop 27 Diffraction fringes at 3.6 cm (Voyager I) on Encke gap of Saturn's rings 1995-991869-89 (Flammarion, 1894) 28 Breanna Microsoft PowerPoint - 150.lec9.Saturn_etal.ppt [Read-Only]