Download Chapter 29.3

Ch. 29.3 The Outer Planets
 Consist of the gas giant planets Jupiter,
Saturn, Uranus, and Neptune.
 Pluto is recently demoted, and is no longer
considered a planet(It’s a dwarf planet).
 The gas giants are more massive, but much
less dense than the inner planets.
 Thick hydrogen / helium atmospheres, with
probable dense cores.
 Since they are similar to Jupiter, they
are also known as Jovian planets.
The Gas Giants
Jupiter
 5th planet from the sun.
 The largest; over twice the mass of
all other planets combined.
 Orbit period is 12 years.
 Fastest rotation; once every 9 hours
and 50 minutes.
 Many moons (63 at last count) and at
least 4 rings.
 High internal temp. due to intense
pressure (30,000 C).
 Resulting metallic hydrogen creates
enormous magnetic field.
 Composed of 92% hydrogen and
helium (similar to the sun; a failed
star?).
 No solid surface.
 Alternating swirling (due to rapid
rotation) colorful bands suggest
ammonia, methane, and water vapor.
 Great Red Spot is giant rotating
storm several hundred years old.
Jupiter
The Great Red Spot
Saturn
 6th planet; 2nd largest in the solar
system.
 Avg. temp. -176 C.
 Many moons (61 at last count) and a
large, complex ring system.
 Rapid rotation, once every 10 hours
and 30 minutes.
 Bands of colored clouds.
 Least dense planet (lower density
than water).
 Orbit period 29.5 years.
Saturn
Uranus
 7th planet from the sun; 3rd largest.
 Discovered in 1781 (1st planet
discovered since ancient times).
 Almost 3 billion km from the sun.
 At least 22 moons and 11 small rings.
 Horizontal rotation, once every 17
hrs.
 Orbit period 84 years.
 Greenish atmosphere color from
methane, with atmosphere mostly
hydrogen and helium.
 Surface temp. -214 C.
 Interior may be water and methane
slush.
 Temp. increases with depth, up to
7000 C in a rock / metal core.
Uranus
Neptune
 8th planet; 4th largest, but very
similar to Uranus in size and mass.
 Orbit period 164 years. Rotates once
every 16 hours. 11 moons, 4 rings.
 Existence predicted before it was
discovered, after astronomers noticed
variations in Uranus’ expected orbit.
 Position was determined
mathematically, then it was
discovered there in the mid-1800’s.
 4.5 billion km from the sun.
 Blue-green color, with white clouds of
frozen methane in the upper part of
the hydrogen/helium atmosphere.
 Strong winds, over 1000 km/hr.
 An Earth-sized storm, the Great Dark
Spot.
 Surface temp. -225 C.
Neptune and its large moon Triton