b. a. Moons of Jupiter – total of 63 confirmed!
Inner moons closer to Jupiter than Io
Amalthea
Jupiter’s Galilean Satellites – Worlds of their own! IoEuropaGanymedeCallisto To Jupiter
Sizes of some of the Galilean satellites of Jupiter
Jupiter’s moon Io, volcanologically the most active body in our Solar System. 1.) Color - sulfur! 2.) Albedo - 63 % 3.) No impact craters - fresh surface 4.) Recent lava flows 5.) Numerous calderas 6.) Numerous active volcanoes, spewing out sulfur and silicate lava
Io
Voyager’s discovery of active volcanic plumes on Io
Views of Pele Plume: 1,300 km wide 600 km high
Limb view Plume shadow Plumes seen on limb and as shadows on surface
Long lava flows at Ra Patera > 100 km long
Lava flows on Io
Examples of lava lakes at Kilauea, 1988
Where does the heat come from on Io? Tidal heating from Jupiter, Europa and Ganymede
Iron-rich core Molten interior Thin silicate crust Interior of Io; density = 3.55 gm/cc
Jupiter’s Galilean Satellites – Worlds of their own! IoEuropaGanymedeCallisto To Jupiter
Europa: 3,138 km diameter; density 3.04 gm/cc
Ideas for a frozen interior for Europa
Ideas for a liquid interior for Europa
How do we get heat into the interior of Europa? Tidal heating. Europa is tugged towards Jupiter, but is also pulled away from Jupiter by Io, Ganymede and Callisto. Without tidal heating, Europa would look like Callisto.
Colored bands – fractures in ice crust
Multiple periods of fracturing
Topography of fractures on Europa
Some craters are found on Europa – but very young!
“Icebergs” on Europa suggest thin (5 – 20 km) crust
If there is volcanism on Europa, ice may be thin, so….. Model of hot interior of Europa Black smokers on Earth Tube worms on Earth’s ocean floor hint that similar life could evolve on Europa without sunlight
Ganymede: 5,262 km diameter; density 1.94 gm/cc (Mercury diameter = 4,880 km)
Light and dark terrain on Ganymede – long geologic history
Grooves on Ganymede – signs of surface movement similar to plate tectonics on Earth?
Grooved Terrain on Ganymede
Signs of comet impacts? Chains of craters with ejecta
Liquid water Magnetometer data give clue to interior of Ganymede Silicate lower mantle Ice crust Iron core
Callisto: Diameter 4,800 km, density 1.86 gm/cc
Thousands of craters at all scales on Callisto
Valhalla basin - ~600 km in diameter
Details of a “ring” of Valhalla Basin
Magnetometer data give clue to interior of Callisto Solid rock-ice Ice-rich outer layer
Relative ages of the surfaces of the Galilean Satellites: From left to right, from young to old.