The Outer Planets

The Outer Planets to Scale

Jupiter Saturn Uranus Neptune Pluto

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 in solar

system(11 time larger than Earth)

• Colorful cloud bands

• Rotation = 10 hours

• -250°F

• 60 moons orbit it

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

• Largest known storm in solar system

Saturn• Least dense planet -

Would float on water!

• Revolves around sun once every 29 yrs.

• One day = 11 hours

• Has at least 31 moons largest is Titan

Saturn’s Rings• Made of countless small

chunks of ice and rock

• 170,000 miles wide, <1 mile thick

• Edge of ring system points towards Earth

• Cassini (1997) put probe on Titan in 2004

Uranus• Discovered by accident

(1781)Blue-green color 350°F at cloud tops

• 1977 discovered it has a faint, dark ring system

• 1986 Voyager 2 spacecraft studied rings and moons

• At least 11 rings and 22 moons

Uranus’ Axis

• Axis tilted 98° from its orbit• One orbit of sun = 84 Earth years• Uranus rotates on its axis once every 17 hours

What’s Wrong with Uranus?

• Following its discovery, astronomers calculated its orbit

• Uranus mysteriously speeded up, then slowed down

Neptune• Discovered at its predicted

position (1846)• 1 rev = 164 Earth years• Blue color -370°F at cloud

tops• 4 rings- 2 thin, 2 thick

• Great Dark Spot in 1989, but not 1994

• Rotates once on its axis every 16 hours

• Wispy, white streaks are clouds

Pluto

- Coldest, outermost planet

- Has not been visited by a spacecraft

- Smallest planet- Only outer planet without

ring system and thick atmosphere

- One moon- Charon- 6 billion kilometers from sun

- One rev = 248 Earth days- Rotates once every 6 days

The S.S. Family Portait

* Rocky object, smaller than a planet, that orbits a star

Most are smaller than a kilometer in diameter few are 1,000 kilometers across

Few come close to Earth and are captured by Earth’s gravity

If one is big enough and does not completely burn up, it could possibly hit Earth.

Asteroid Belt• Region between Mars and Jupiter where most asteroids

orbit the sun

• Brief streak of light seen when an asteroid enters the earth’s atmosphere and burns up

“ shooting stars”

“ falling stars”

“meteor shower”

• Asteroid that hits the surface of a planet or moon after traveling through space

* Ball of ice, rock, frozen gases and dust that orbits the sun