The Outer Planets Gas Giants Pluto Jupiter Saturn

The Outer Planets

Gas Giants & Pluto • Jupiter, Saturn, Uranus and Neptune • They are much more massive than Earth • Do not have solid surfaces • Composed of Hydrogen and Helium • Thick atmospheres from strong gravity. • They all have many moons and rings • Pluto is a dwarf planet.

Jupiter • The largest and most massive planet.

Jupiter’s Atmosphere • Thick atmosphere of hydrogen and helium • Great Red Spot- a storm larger than Earth. • Similar to a hurricane but this storm never gets weaker. It has been around since the mid-1600’s.

Jupiter’s Structure • Core of rock and iron. • Thick mantle of hydrogen and helium. • Thick atmosphere.

Jupiter’s Moons • Galileo discovered Jupiter’s 4 largest moons. • They are all larger than Earth’s moon. • Each moon is different. • Jupiter has over 63 moons.

Saturn • The second largest planet in the solar system. • Thick atmosphere. Contains clouds and storms. • Average density is less than water.

Saturn’s Rings • Made of ice and rock. • Each noticeable ring is made up of several thinner rings.

Saturn’s Moons • Largest moon- Titan • Has over 56 moons.

Uranus • 4 times the diameter of Earth. • Very cold. • Blue-green color because there are traces of methane in the atmosphere. • Surrounded by rings.

Discovery of Uranus • Discovered in 1781 • William Herschel proved Uranus was a planet.

Exploring Uranus • Voyager 2 • Discovered that the planet rotates at an angle of 90 degrees from the vertical. • It rotates from top to bottom instead of sideto-side!

Uranus’s Moons • 5 largest moons have icy, cratered surfaces. • Lava flows • At least 27 total moons

Neptune • A cold, blue planet. • Atmosphere contains visible clouds. • Similar in size and color to Uranus.

Discovery of Neptune • Discovered as a result of a mathematical prediction. • They thought an unseen planet (Neptune) was affecting Uranus’s orbit.

Exploring Neptune • Voyager 2 photographed a Great Dark Spot about the size of Earth. • Probably a giant storm. • Storm didn’t last long.

Neptune’s Moons • There at least 13 moons. • Triton is the largest moon. • Triton’s south pole is covered by nitrogen ice.

Pluto • Solid surface. • Much smaller and denser than the outer planets. • Smaller than Earth’s moon! • Has at least 3 moons.

Pluto’s orbit • Very elliptical. • Crosses Neptune’s orbit.

Dwarf Planets • Round and orbits the sun like a planet. • However, dwarf planets have not cleared out the neighborhood around its orbit.