Class 8: Jupiter, Saturn, Uranus, Neptune, Pluto

Today’s topics: Jupiter & Saturn Jupiter: Internal structure, magnetic field atmosphere, moons Saturn: Exploration, internal structure, rings The other guys: Uranus, Neptune, Pluto Class Updates Reading: 23.2, Midterm 2: April 18th Class 8: Jupiter, Saturn, Uranus, Neptune, Pluto

mostly H 2 Size (radius) 6378 km 11x Earth Jupiter: A Global Perspective Differences Earth Jupiter Mass 6x10 24 kg 317x Earth Density 5.5 g/cm 3 1/4 of Earth Atmosphere 78% N 2 21% O 2 86% H 2 14% He Surface temperature 20°C -120°C Plate tectonics yes no Tectonism, volcanism yes no Liquid water yes no Rotation 1 day 2/5 of Earth Orbit 1 yr 11.9 yrs

Pioneer 10 & 11 fly-bys 1974/75US Exploration of Jupiter Cassini Galileo Voyager 2 Pioneer 10 Voyager 1 & 2 fly-bys 1979US Galileo fly-by US probe Cassini fly-by 2004US/Europe

Jupiter’s Internal Structure ~12,000 km 60,000 km (1) (2) (3) core 30,000 °C

Electron (-1) Nucleus: Proton (+1) Neutron (0) Molecular & Metallic Hydrogen

Magnetic Field Generation? rocky core liquid metallic hydrogen molecular hydrogen Earth Jupiter

Jupiter’s Magnetic Field artist’s rendition

Jupiter’s Atmosphere Voyager 2 Voyager 1 warmcool

The Great Red Spot

2006: New “Junior” Red Spot

Jupiter’s Rings Voyager 1 (pseudo color) Halo Ring (inner-most)

Jupiter & moons (backyard telescope) 1,000,000 miles Jupiter’s Moons

Jupiter’s Moons: 65 & counting……..

Saturn

mostly H 2 Saturn: A Global Perspective Size (radius) 6378 km 9x Earth Differences Earth Saturn Mass 6x10 24 kg 95x Earth Density 5.5 g/cm g/cm 3 Rotation 1 day 1/2 of Earth Atmosphere 78%N 2 21%O 2 90%H 2 10%He Surface temperature 20°C -180°C Plate tectonics yes no Tectonism, volcanism yes no Liquid water yes no

Exploration of Saturn CassiniVoyager 2 Voyager 1 & 2 fly-bys 1979US Cassini-Huygens orbiter (Saturn)2004US/Europe probe (Titan) 2005 Huygens Probe

Cassini Observations

Saturn’s Internal Structure (I) (1) Layer 1: molecular hydrogen 30,000 km Layer 3: water, methane, ammonia (3) (2) Layer 2: metallic hydrogen Core: heavy-elements(?) core

Saturn’s Internal Structure (II) molecular H core Saturn: 0.70 g/cm 3 metallic H less dense than Jupiter Jupiter: 1.3 Water: 1.0

Saturn’s Rings

Saturn’s Rings Characteristics

Mimas Enceladus Titan Epimetheus Rhea Saturn’s Moons Dione Tethys Iapetus

Uranus, Neptune, and Pluto

Solar System Distances *Planets not to scale Distances not to scale

Uranus: A Global Perspective Differences EarthUranus Size (radius) 6378 km4x Earth Mass 6x10 24 kg 145 Earth Density 5.5 g/cm g/cm 3 (methane) Atmosphere 78%N 2 21%O 2 84%H 14%He 2%CH 4 Surface temperature 20°C -200°C Rotation 1 day hours Orbit 365 days84.01 years Satellites 1 27

Exploring Uranus Herschel Uranus moons Voyager 2 Hubble Space Telescope

Uranus’s Interior (1) (2) core METHANE

Axis of Rotation 98 ° Uranus 23.5° Earth

Atmosphere & Magnetic Field ultraviolet visible rotation axis magnetic axis 58°

The Rings of Uranus dust bands

Ariel Umbriel Oberon (2nd largest) Titania (largest) Miranda Puck Total: 27 The Moons of Uranus r ≈ 789 km

Neptune: A Global Perspective Differences EarthNeptune Size (radius) 6378 km3.9x Earth Mass 6x10 24 kg 171 Earth Density 5.5 g/cm g/cm 3 (methane) Atmosphere 78%N 2 21%O 2 84%H 14%He 2%CH 4 Surface temperature 20°C -210°C Rotation 1 day 16 hours Orbit 365 days 165 years Satellites 111

Exploring Neptune Adams Le Verrier Galle Voyager 2

Neptune’s Interior H, He, CH 4 H 2 O, CH 4, NH 3 (1) (2) core

Neptune’s Atmosphere & Clouds Scooter Neptune clouds

The Great Dark Spot Voyager 2 GDS changesVoyager 2

Neptune’s Rings & Moons faint rings Triton

A Parting Look

Pluto: A Global Perspective Similarities EarthPluto Moon1 - Moon1 - Charon Size (radius)6378 km0.2x Earth Differences Mass6x10 24 kg 0.002x Earth Density5.5 g/cm 3 0.4x Earth Atmosphere 78% N 2 21% O 2 probably N 2, thin Surface temperature20°C -220°C Rotation 1 day 6.4 days Orbit365 days248 years

Exploring Pluto Tombaugh, Lowell Observatory Charon Photo 1Photo 2 planetary symbol

Pluto’s Elliptical Orbit

Pluto: Is it a planet?

Real Planets & Dwarf Planets ErisPlutoCeres

Pluto’s Size & Interior core

Pluto - Charon System 112 °

Pluto and Charon from Hubble Bright/dark regions: differences in methane/nitrogen frost cover

New Horizons Mission