Chapter 7

The Outer Planets

What do you think?

• Is Jupiter a “failed star” or almost a star?

• What is Jupiter’s Great Red Spot?

• Does Jupiter have continents and oceans?

• Are the rings of Saturn solid ribbons?

Besides being the largest planet,

Jupiter is probably best known for its

Great Red Spot - a hurricane-like storms

that has been observed ever since the invention of the

telescope.

Jupiter’s rotation helps create

colorful global weather patterns

Jupiter’s rotation helps create colorful global weather patterns

Jupiter’s Chemistry

• 86% hydrogen

• 13% helium

• 1% stuff– methane CH4

– ammonia NH3

– water vapor H2O

The light zones are regions of hotter, rising gas, while the dark belts are regions of cooler, descending gas.

Jupiter’s interior has three distinct regions

• Upper atmosphere of clouds and gas

• Middle layer of liquid metallic hydrogen

• Small rocky protoplanet core

Pieces of Comet Shoemaker-Levy 9 fragments collided with Jupiter in 1994

Jupiter is orbited by four large moons and tens of small ones

Io’s surface is sculpted by volcanic activity

Io’s surface is sculpted by volcanic activity

Europa may harbor liquid water below its surface

Ganymede is larger that Mercury

Callisto wears the scars of a huge asteroid

impact

Saturn’s banded surface and

layered interior are similar to those of

Jupiter

Saturn’s spectacular rings are composed of fragments of ice and ice-coated rock

Moons Pandora and Prometheus act as shepherd moons and keep the F ring to a band about 100km wide because of gravitational effects.

Dust spokes in Saturn’s rings

Titan is Saturn’s largest moon

Titan has a thick, opaque

atmosphere rich in nitrogen, methane

and other hydrocarbons

(including ethane, acetylene, ethylene,

and propane)

Uranus sports a hazy atmosphere with few clouds

A system of rings and satellites revolves around Uranus

Uranus’ odd moon Miranda

Uranus’ tilt gives it very exaggerated seasons

Uranus and Neptune have similar interiors

Neptune’s Rings

Neptune’s largest moon, Tritan, was probably captured by Neptune’s gravity

And then, there is one planet unlike any of the others …..

Pluto was discovered in 1930 by Clyde Tombaugh by comparing photographs

taken a few days apart.

Pluto and its moon, Charon, are about the same

size

What did you think?• Is Jupiter a “failed star” or almost a star?

Jupiter has 75 times too little mass to shine as a star.

• What is Jupiter’s Great Red Spot?The Great Red Spot is a long-lived hurricanelike storm.

• Does Jupiter have continents and oceans?Jupiter is completely enveloped in a sea of liquid hydrogen and helium

• Are the rings of Saturn solid ribbons?Saturn’s rings are all composed of thin, closely spaced ringlets

consisting of particles of ice and ice-coated rocks. If they were solid ribbons, Saturn’s gravitational tidal force would tear them apart.

Self-Check1: Name and describe the visible features in the Jovian atmosphere.

2: Sketch and label the major elements of the ring system of Saturn and describe its composition.

3: Compare and contrast the atmospheres of Jupiter and Saturn.

4: Compare and contrast the internal structures of Jupiter and Saturn with that of Uranus and Neptune.

5: Compare and contrast the ring systems of the outer planets.

6: Compare and contrast the atmospheric features of Uranus and Neptune.

7: Describe the geologic activity observed on Io and explain the probable origin of this activity.

8: Compare and contrast the inner and outer Galilean satellites in terms of internal structure and surface features.

9: List the gases that compose Titan’s atmosphere and discuss the possibility of the existence of life forms there.

10: Compare and contrast the Voyager 2 observations of Triton with those of Titan in terms of atmospheric composition and surface features identified.

11: Describe the physical properties of Pluto in the context of planetary classification.