Transcript The Outer Planets

The Outer Planets
The Inner Planets to Scale
3,031 mi
5.4 g/cm3
7,521 mi
7,926 mi
5.2 g/cm3
5.5 g/cm3
4,222 mi
3.9 g/cm^3
The Outer Planets to Scale
88,700 mi
75,000 mi 31,700 mi 30,200 mi
1.3 g/cm3
0.7 g/cm3
1.3 g/cm3 1.6 g/cm3
Outer Planet Similarities
• All are tens of thousands of miles across
– Much larger than the inner planets
• All are made of gas - hydrogen and helium
– No rocky surface like the inner planets
• All are not very dense (b/c made of gas)
• Why do the outer planets share these
similarities?
• Why don’t the outer planets have more in
common with the inner planets?
Jupiter
• Largest planet
• Colorful cloud bands
• Rapid rotation
(9h50m)
• -250°F at cloud tops
• Great Red Spot
Great Red Spot
• Hurricane-like storm,
fueled by heat inside
of Jupiter
• Large enough to
cover 3 Earths
• Discovered by Galileo
nearly 400 years ago
– Why can it last so long
compared with
hurricanes on the
Earth?
Saturn
• Least dense planet Would float on water!
• Bulges because of
rapid rotation
(10h30m)
• Large, broad rings
Saturn’s Rings
• Made of countless
small chunks of ice
and rock
– Why don’t the chunks
combine to form a
moon?
– Why doesn’t Earth
have rings?
• 170,000 miles wide,
<1 mile thick
Uranus
• Discovered by
accident (1781)
• Blue-green color from
methane in its
atmosphere
• -350°F at cloud tops
• Almost featureless;
little weather
– Why might Uranus
lack distinctive
weather patterns?
Uranus’ Axis
• Axis tilted 98° from its orbit
• Orbits Sun every 84y
• How would these factors affect its seasons?
What’s Wrong with Uranus?
• Following its
discovery,
astronomers
calculated its orbit
• Uranus mysteriously
speeded up, then
slowed down
– Why might Uranus
have deviated from its
calculated orbit?
Neptune
• Discovered at its
predicted position
(1846)
• Blue color from methane
• -370°F at cloud tops
• Great Dark Spot in
1989, but not 1994
– How is this different from
the Great Red Spot?
– Why is its weather
different from Uranus?
Jupiter?
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