Reviewing the Inner Planets

Reviewing the Inner Planets Terrestrial planets: Have a solid, rocky surface Revolution periods are relatively short Are very dense No rings and few moons Relatively long rotation periods Small diameter Between the Sun and Asteroid Belt

The Outer Planets Subtitle

The Gas Giant Planets Include Jupiter, Saturn, Uranus, and Neptune Very large (15 to more than 300 times the mass of Earth) Interior: Gases or liquids (might have solid inner cores) Made primarily of very light elements (H, He, C, N, and O) Very cold at their surfaces Have many satellites (moons) as well as ring systems

JUPITER Appears bright (albedo of 0.343) Banded appearance as a result of flow patterns in its atmosphere Great Red Spot (400 year-old storm) Largest planet * Gravity assist

JUPITER Rings: Voyager I discovered the first ring (1979) Galileo on a 7 year mission found two smaller rings (1990’s and 2000’s) New Horizons confirmed one more ring (2007) Made of dust particles

JUPITER Atmosphere: It has a low density for its size. Below the liquid hydrogen is a layer of LIQUID METALLIC HYDROGEN which can only exist under very high pressure. Moons: More than sixty. Four largest are Ganymede, Callisto, Io, and Europa. All four are composed of ice and rock. Rotation period: 10 hours (shortest day among the planets) . Its fast rotation causes its clouds to flow rapidly forming bands of different colors. * BELTS: low, warm, dark-colored clouds that sink * ZONES: high, cool, light-colored clouds that rise

* BELTS: low, warm, dark-colored clouds that sink * ZONES: high, cool, light-colored clouds that rise enchantedlearning.com

SATURN Second-largest planet Cassini –Hyugens mission (1997-2017) Average density is lower than that of water Rotates rapidly for its size (10 hours 14 minutes) causing a layered cloud system.

SATURN Atmosphere: Mostly HYDROGEN and HELIUM with AMMONIA ICE near the cloud tops. Internal structure probably similar to Jupiter’s

SATURN RINGS Much broader and brighter Composed of ice 7 major rings (made up of ringlets) MOONS More than sixty moons Largest is Titan: Dense atmosphere made of nitrogen and methane. Images suggest cryovolcanic activity.

URANUS Seventh planet from the Sun Four times larger than Earth, but much more massive Its rotational axis is tipped so far that its north pole almost lies in its orbital plane Rotation period of 17 hrs 14 min Retrograde rotation Coldest planet: Average T° of -224°C

URANUS Atmosphere: It is mostly made of He and H. It also has methane which gives the planet its blue appearance. There are a few clouds. Internal structure: Similar to Jupiter and Saturn’s (completely fluid except for a small, solid core) Moons: 27 moons (Voyager 2 in 1986) ; largest Oberon and Titania “Sweet Moon, I thank thee for thy sunny beams; I thank thee, moon, for shining now so bright.” Rings: There are 13 known rings, the largest being the Epsilon Ring. Made mostly of dark dust.

Neptune Last of the gas giant planets; about 4.5 billion km away from the Sun Voyager 2 flew past Neptune in 1989 Similarities with Uranus * About the same size (a bit smaller and more dense) * Atmosphere of Helium, Hydrogen, and Methane * Bluish color caused by methane * Similar temperatures (Uranus slightly cooler) * Rotation periods (Neptune 16 hrs; Uranus 17 hrs)

Neptune Atmosphere: Unlike Uranus, Neptune has distinctive clouds and atmospheric belts and zones (similar to Jupiter and Saturn). It can have persistent storms. The most recent was the Great Dark Spot (1994). Moons: 13 moons, the largest being Triton Rings: Six rings composed of microscopic dust particles which do not reflect light well.

Compare and Contrast Inner and Outer Planets