Grade 8 Integrated Science Chapter 11 Lesson 3 on the outer planets. This lesson discusses the four outer planets. It gives details on their composition, atmosphere, rings, moons, and other identifying details.

1. The Outer Planets
Ch 11.2 (p390-396)

2. Vocabulary
• Galilean moons (393) – The four largest
moons of Jupiter – Io, Europa, Ganymede,
and Callisto – which were first discovered
by Galileo Galilei in 1610

3. The Gas Giants
• The outer planets are called the gas
giants because they are primarily made of
hydrogen and helium.
• They have strong gravitational forces due
to their large masses.
– The strong gravity creates tremendous
atmospheric pressure that changes gases to
liquids.
– Most these planets have thick gas and liquid
interiors covering a small, solid core

5. Jupiter
• Largest planet
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11 times the diameter of Earth
Twice the mass of all the other planets combined
Rotates faster than any other planet
Like all outer planets, it has a ring system

6. Jupiter’s Atmosphere
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90% hydrogen, 10% helium
1000km deep
Dense, colorful clouds
Because Jupiter rotates so quickly, the clouds
stretch into bands
• The Great Red Spot is a storm of swirling gases

7. Jupiter’s Structure
• 80% hydrogen, 20% helium
• Thick solid core
• 1000km past the outer edge of
the cloud layer, the pressure is
so great hydrogen gas changes
to liquid
• Scientists do not know what the
core is made of
– They suspect it is rock and iron

8. The Moons of Jupiter
• Jupiter has at least 63 moons
• The 4 largest were discovered by Galileo
in 1610
– We call these Galilean Moons
• Io, Europa, Ganymede, and Callisto
• All made of rock and ice
• Collisions between Jupiter’s moons and
meteorites likely resulted in Jupiter’s rings

10. Saturn
• 6th planet
• Has horizontal bands of
clouds
• 90% hydrogen, 10%
helium
• Least dense planet
– Its density is less than that
of water

11. Saturn’s Structure
• Similar to Jupiter
– An outer gas layer, a thick layer
of liquid hydrogen, and a solid
core
• Ring system is the largest and
most complex
– 7 bands of rings, each containing
thousands of narrower ringlets
– Main ring system is over
70,000km wide and less than
30m thick

12. Saturn’s Moons
• At least 60 moons
• 5 largest – Titan, Rhea, Bdione, Iapetus,
and Tethys
• Most of Saturn’s moons are chucks of ice
less than 10km in diameter
• Titan is larger than Mercury
– It is the only moon in the solar system with a
dense atmosphere
– In 2005 the Huygen probe landed on Titan

13. Uranus
• 7th planet
• Narrow, dark rings
• Deep atmosphere composed mostly of hydrogen
and helium and some methane
– The methane gas gives it a bluish color
• Beneath the atmosphere is a thick, slushy layer
of water ammonia, and other materials
• Below that is a solid, rocky core

14. Uranus’s Axis and Moons
• Uranus has a tilted axis of rotation
– Maybe caused by a collision with an Earth-sized
object
• At least 27 moons
– Largest are Titania and Oberon (smaller than our
moon)
• Titania has an icy cracked surface that might once have
been covered by an ocean

15. Neptune
• Discovered in 1846
• Atmosphere is like Uranus
– Hydrogen, helium, and some methane
• Interior is also like Uranus
– Partially frozen water and ammonia with a rock and iron core
• 13 moons and a faint ring system
– Triton is the largest. It has a surface of frozen nitrogen and
geysers that erupt nitrogen gas
• Swirling storm s and high winds sometimes exceeding
1000km/h