Chapter 23 The Solar System Section 2 Outer Planets Notes 23-4

Saturn

Saturn Sixth planet from the sun Sixth planet from the sun Over a half a billion km farther from the sun than Jupiter Over a half a billion km farther from the sun than Jupiter Second largest planet Second largest planet Average temperature = -176 °C Average temperature = -176 °C Has 34 named satellites Has 34 named satellites Has several rings Has several rings

Saturn Rotation rate = 10 hours and 30 minutes Rotation rate = 10 hours and 30 minutes Bulges at its equator and flattens at its poles Bulges at its equator and flattens at its poles Orbital Period = 29.5 years Orbital Period = 29.5 years Also has colored bands Also has colored bands Probably caused by the quick spinning Probably caused by the quick spinning Made of 75% hydrogen and 25% helium Made of 75% hydrogen and 25% helium Mostly liquid metallic hydrogen Mostly liquid metallic hydrogen Has trace elements of ammonia, methane and water vapor Has trace elements of ammonia, methane and water vapor Probably has a rocky core (like Jupiter) Probably has a rocky core (like Jupiter)

Saturn Differences from Jupiter Differences from Jupiter Less dense Less dense Less dense than water; could float Less dense than water; could float Orbital period is much longer Orbital period is much longer Complex ring system Complex ring system

Uranus

Uranus Seventh planet from the sun Seventh planet from the sun Third largest planet Third largest planet First planet to be discovered since ancient times (1781) First planet to be discovered since ancient times (1781) Has 27 moons Has 27 moons 11 dark rings (makes them hard to see) 11 dark rings (makes them hard to see) Orbital period = 84 years Orbital period = 84 years Rotation rate = 17 hours Rotation rate = 17 hours

Uranus Rotates like a rolling ball Rotates like a rolling ball Axis is horizontal to its orbit Axis is horizontal to its orbit Visited only once in 1986 Visited only once in 1986 By Voyager 2 By Voyager 2 Greenish in color Greenish in color From methane in its outermost atmosphere From methane in its outermost atmosphere Also has helium and hydrogen Also has helium and hydrogen But not as much as Saturn and Jupiter But not as much as Saturn and Jupiter

Uranus Average temperature -214 °C Average temperature -214 °C May have liquid water and methane on the interior May have liquid water and methane on the interior It material is more uniform through out the planet It material is more uniform through out the planet No rocky core (like the book says) No rocky core (like the book says) Imagine Saturn and Jupiter without the atmosphere and liquid metallic hydrogen Imagine Saturn and Jupiter without the atmosphere and liquid metallic hydrogen

Neptune

Neptune Eighth planet from the sun Eighth planet from the sun Fourth largest Fourth largest Smaller in diameter than Uranus but bigger in mass Smaller in diameter than Uranus but bigger in mass Orbital period = 164 years Orbital period = 164 years Rotation rate = 16 hours Rotation rate = 16 hours Has 13 moons Has 13 moons Has 4 rings Has 4 rings

Neptune Named after Roman god of the sea Named after Roman god of the sea John Couch Adams and Urbain Leverrier in 1800’s predicted the location of another planet John Couch Adams and Urbain Leverrier in 1800’s predicted the location of another planet Johann Galle, discovered the planet in 1846 Johann Galle, discovered the planet in 1846 Galileo actually saw it first, when studying Jupiter, but thought it was a star Galileo actually saw it first, when studying Jupiter, but thought it was a star Has only been visited by Voyager 2, in 1989 Has only been visited by Voyager 2, in 1989

Neptune Great Dark Spot (like Jupiter’s Great Red Spot) Great Dark Spot (like Jupiter’s Great Red Spot) Large storm Large storm Around the same size as Earth Around the same size as Earth 1994 it disappeared 1994 it disappeared Has strongest winds in the solar system Has strongest winds in the solar system Reaching 2000 km/hr Reaching 2000 km/hr Average surface temp. = -225 °C Average surface temp. = -225 °C

Pluto

Pluto Dwarf planet Dwarf planet Discovered in 1930 by Clyde Tombaugh, in Flagstaff, Arizona Discovered in 1930 by Clyde Tombaugh, in Flagstaff, Arizona Diameter of 2,390 km Diameter of 2,390 km Rotation rate = 6 days Rotation rate = 6 days Orbital period = 250 years Orbital period = 250 years

Pluto Has an elongated ellipse orbit Has an elongated ellipse orbit Is sometimes inside Neptune’s orbit Is sometimes inside Neptune’s orbit Made of frozen methane, rock and ice Made of frozen methane, rock and ice Average temp = -236 °C Average temp = -236 °C Has methane ice caps Has methane ice caps Has methane atmosphere Has methane atmosphere When it isn’t frozen When it isn’t frozen

Pluto Has one main moon = Charon Has one main moon = Charon Discovered in 1978 Discovered in 1978 Appear to be a double planet system Appear to be a double planet system Because they orbit so closely Because they orbit so closely Found as an accident Found as an accident Has two smaller moons orbiting it Has two smaller moons orbiting it Nix and Hydra Nix and Hydra Between 50 – 60 km in diameter Between 50 – 60 km in diameter