The Jovian Worlds
The visitors
Pioneer 10, 11; Voyager 1,2 Galileo [1995]; Cassini [2004]
Completely different chemical composition than terrestrials. They are H and He
Core, liquid, deep gas atmosphere
Rotation rates measured by magnetospheres – interior rotation
Oblateness (Saturn ~ 10%)
Internal energy source
Jupiter’s 2x solar irradiation contraction
Saturn’s 2x differentiation He
Uranus none
Mass vs. radius Jupiter is about as large as you get
Saturn is less dense, but Uranus and Neptune are not Why?
CH4, NH3, H2O and other H compounds
Jupiter et al. structure from Galileo probe
Zones and belts circulation pattern
Coriolis gives storms including the Great Red Spot, [movie] storms
Colors from impurities
Saturn is ‘paler’ storms Deeper and cooler atmosphere than Jupiter
Uranus and Neptune cold enough for methane ice clouds = blue [Neptune movie]
Seasons affects Uranian atmosphere
Jupiter has the largest
The others field and magnetosphere
For Uranus and Neptune the ‘water’ layer
Satellites
Some of them Jupiter Saturn Uranus Neptune
Lots of small stuff – but who’s counting?
Dividing them by size helps understand them
0-300km; 300-1500km [spherical]; over 1500km [almost planets]
The big seven: Io, Europa, Ganymede, Callisto, Titan, Triton (Moon)
Ice geology
Larger objects: rocky cores with ice mantle
Ice is dirty
The usual: impact, vulcanism, tectonic not much erosion, if any
Io globe, [movie] vulcanism, hot spots
Tidal heating orbital resonance
Europa globe tectonic cracks hot spots subsurface oceans(?) life?
Ganymede globe grooves ice plates small magnetic field
Callisto globe craters not differentiated, black dust?
Titan Huygens probe 2005 landing
Atmosphere cloud covered layers model
Interior under crust liquid ammonia/water mixture
Methane channels from methane rain
Why does Titan have an atmosphere and Ganymede does not?
Triton polar cap, [movie] cantaloupe terrain, thin atmosphere
Mimas, Enceladus, Thethys, Dione, Rhea, Iapetus
Miranda, Ariel, Umbriel, Titania, Oberon
Just being average doesn't make you less interesting
Enceladus with geysers of water
Iapetus strange color and shape
The forces that shape rings
The planet’s gravity (Kepler)
Planet’s oblateness causes flatness
Thin rings and shepherd satellites
Gaps due to resonances and gap moons
ripples and more ripples due to gravity of gap moons
Smaller yet - evidence of 'propeller' moons
Dust(icy) and larger, seen by how it scatters light Dust in gaps
Other Rings
Tidal disruption of large moons and leftovers not popular theories any more
Best guess: Chipping away of small moons
