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Class 8: Jupiter, Saturn, Uranus, Neptune, Pluto. Class 8: Jupiter, Saturn, Uranus, Neptune, Pluto. Class Updates • Reading: 23.2, 23.4-23.6 • Midterm 2: April 18th . Today’s topics: Jupiter & Saturn Jupiter: Internal structure, magnetic field atmosphere, moons
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Class 8: Jupiter, Saturn, Uranus, Neptune, Pluto
Class 8: Jupiter, Saturn, Uranus, Neptune, Pluto Class Updates • Reading: 23.2, 23.4-23.6 • Midterm 2: April 18th • Today’s topics: Jupiter & Saturn • Jupiter: Internal structure, magnetic field • atmosphere, moons • • Saturn: Exploration, internal structure, • rings • The other guys: Uranus, Neptune, Pluto
Jupiter: A Global Perspective mostly H2 Differences Earth Jupiter • Size (radius) 6378 km 11x Earth • Mass 6x1024 kg 317x Earth • Density 5.5 g/cm31/4 of Earth • Atmosphere 78% N2 21% O286% H2 14% He • Surface temperature 20°C -120°C • Rotation 1 day 2/5 of Earth • Orbit 1 yr 11.9 yrs • Plate tectonics yes no • Tectonism, volcanism yes no • Liquid water yes no
Exploration of Jupiter • Pioneer 10 & 11 fly-bys 1974/75 US • Voyager 1 & 2 fly-bys 1979 US • Galileo fly-by 1995-2003 US probe • Cassini fly-by 2004 US/Europe Voyager 2 Cassini Pioneer 10 Galileo
Jupiter’s Internal Structure (1) ~12,000 km (2) 30,000 °C (3) core 60,000 km
Molecular & Metallic Hydrogen Electron (-1) Nucleus: Proton (+1) Neutron (0)
Magnetic Field Generation? Earth Jupiter rocky core molecular hydrogen liquid metallic hydrogen
Jupiter’s Magnetic Field artist’s rendition
Jupiter’s Atmosphere Voyager 1 cool warm Voyager 2
Voyager 1 (pseudo color) Halo Ring (inner-most) Jupiter’s Rings
Jupiter & moons (backyard telescope) 1,000,000 miles Jupiter’s Moons
Saturn: A Global Perspective Differences Earth Saturn • Size (radius) 6378 km 9x Earth mostly H2 • Mass 6x1024 kg 95x Earth • Density 5.5 g/cm3 0.70 g/cm3 • Atmosphere 78%N2 21%O2 90%H2 10%He • Surface temperature 20°C -180°C • Rotation 1 day 1/2 of Earth • Plate tectonics yes no • Tectonism, volcanism yes no • Liquid water yes no
Exploration of Saturn • Voyager 1 & 2 fly-bys 1979 US • Cassini-Huygens orbiter (Saturn) 2004 US/Europe probe (Titan) 2005 Voyager 2 Cassini Huygens Probe
• Layer 1: molecular hydrogen • Layer 2: metallic hydrogen • Layer 3: water, methane, ammonia • Core: heavy-elements(?) (1) (2) 30,000 km (3) core Saturn’s Internal Structure (I)
• less dense than Jupiter Water: 1.0 Jupiter: 1.3 Saturn’s Internal Structure (II) Saturn: 0.70 g/cm3 molecular H metallic H core
Saturn’s Moons Epimetheus Titan Rhea Dione Mimas Tethys Enceladus Iapetus
Solar System Distances *Planets not to scale Distances not to scale
Differences Earth Uranus • Size (radius) 6378 km 4x Earth • Mass 6x1024 kg145 Earth • Density 5.5 g/cm3 1.3 g/cm3 • Atmosphere 78%N2 21%O284%H14%He2%CH4 (methane) • Surface temperature 20°C -200°C • Rotation 1 day -17.9 hours Uranus: A Global Perspective • Orbit 365 days 84.01 years • Satellites 1 27
Exploring Uranus Herschel Uranus moons Voyager 2 Hubble Space Telescope
Uranus’s Interior (1) (2) core METHANE
23.5° 98 ° Earth Uranus Axis of Rotation
rotation axis Atmosphere & Magnetic Field ultraviolet magnetic axis visible 58°
dust bands The Rings of Uranus
The Moons of Uranus Oberon (2nd largest) Total: 27 Titania (largest) r ≈ 789 km Umbriel Miranda Puck Ariel
Differences Earth Neptune • Size (radius) 6378 km 3.9x Earth • Mass 6x1024 kg171 Earth • Density 5.5 g/cm3 1.6 g/cm3 • Atmosphere 78%N2 21%O284%H14%He2%CH4 (methane) • Surface temperature 20°C -210°C • Rotation 1 day 16 hours • Orbit 365 days 165 years • Satellites 1 11 Neptune: A Global Perspective
Exploring Neptune Adams Le Verrier Galle Voyager 2
Neptune’s Interior (1) H, He, CH4 (2) H2O, CH4, NH3 core
Neptune clouds Scooter Neptune’s Atmosphere & Clouds
Voyager 2 GDS changes The Great Dark Spot Voyager 2 Voyager 2
Triton Neptune’s Rings & Moons faint rings
Pluto: A Global Perspective Similarities Earth Pluto • Moon 1 - Moon 1 - Charon Differences • Size (radius) 6378 km0.2x Earth • Mass 6x1024 kg 0.002x Earth • Density 5.5 g/cm3 0.4x Earth • Atmosphere 78% N2 21% O2probably N2, thin • Surface temperature 20°C -220°C • Rotation 1 day 6.4 days • Orbit 365 days 248 years
Photo 1 Photo 2 planetary symbol Exploring Pluto Tombaugh, Lowell Observatory Charon
Real Planets & Dwarf Planets Ceres Pluto Eris
Pluto’s Size & Interior core
112° Pluto - Charon System
Pluto and Charon from Hubble Bright/dark regions: differences in methane/nitrogen frost cover