28.3 Satellites of Other Planets

Std 1F: Know the evidence for the dramatic effects Std 1F: Know the evidence for the dramatic effects that asteroid impacts have had in shaping the that asteroid impacts have had in shaping the surface of planets. surface of planets.

• Objective 1: CompareObjective 1: Compare the characteristics of the two the characteristics of the two moons of Mars.moons of Mars.

• Objective 2: Name Objective 2: Name one distinguishing characteristic one distinguishing characteristic of each of the Galilean moons.of each of the Galilean moons.

• Objective 3: CompareObjective 3: Compare the characteristics of the rings the characteristics of the rings of Saturn with the rings of the other outer planets.of Saturn with the rings of the other outer planets.

Moons of Mars

• Mercury and Venus do not have moons.Mercury and Venus do not have moons.• Saturn, Jupiter, Uranus, and Neptune all have Saturn, Jupiter, Uranus, and Neptune all have

rings.rings.• Mars has 2 moons (Phobos and Deimos)Mars has 2 moons (Phobos and Deimos)

• Have irregularly shapesHave irregularly shapes• Surfaces are dark and have many cratersSurfaces are dark and have many craters

• Possibly captured asteroidsPossibly captured asteroids

Moons of Jupiter

• Galilean moonGalilean moon - any one of the four largest - any one of the four largest satellites of Jupiter—Io, Europa, Ganymede, satellites of Jupiter—Io, Europa, Ganymede, and Callisto - discovered by Galileo in 1610and Callisto - discovered by Galileo in 1610

• 3 are larger than Earth’s moon!3 are larger than Earth’s moon!

Io

• The innermost moonsThe innermost moons• 11stst extraterrestrial body to have active volcanoes extraterrestrial body to have active volcanoes • Eject thousands of metric tons of material each Eject thousands of metric tons of material each

second.second.

Europa

• 22ndnd closest Galilean moon to Jupiter closest Galilean moon to Jupiter• The size of Earth’s moon (less dense.)The size of Earth’s moon (less dense.)• Rock core with a crust of ice that is about 100 Rock core with a crust of ice that is about 100

km thick.km thick.• Liquid water may exists under the ice.Liquid water may exists under the ice.• If liquid water exists, life forms could existIf liquid water exists, life forms could exist

Ganymede

• 3rd Galilean moon from Jupiter 3rd Galilean moon from Jupiter • The largest moon in the solar systemThe largest moon in the solar system• Small mass (composed of ice mixed with rock)Small mass (composed of ice mixed with rock)• The surface has dark, crater-filled areas, and The surface has dark, crater-filled areas, and

light areas that may be ridges and valleys.light areas that may be ridges and valleys.

Callisto

• The farthest Galilean The farthest Galilean moon from Jupiter.moon from Jupiter.

• Callisto is similar to Callisto is similar to Ganymede Ganymede – size, density, and size, density, and

compositioncomposition• Most densely Most densely

cratered moons in cratered moons in our solar system.our solar system.

Moons of Saturn • Saturn has over 30 moons (5 moons are large)Saturn has over 30 moons (5 moons are large)• Saturn’s largest moon is TitanSaturn’s largest moon is Titan

• diameter >5,000 km.diameter >5,000 km.• Titan’s thick atmosphere = mainly of nitrogen.Titan’s thick atmosphere = mainly of nitrogen.

Moons of Uranus and Neptune

• Uranus’s moons (4 largest moons )Uranus’s moons (4 largest moons )• Oberon, Titania, Umbriel, and ArielOberon, Titania, Umbriel, and Ariel• Discovered by mid-1800’s.Discovered by mid-1800’s.• Miranda(5th moon) was discovered in 1948Miranda(5th moon) was discovered in 1948• Has over 12 moons.Has over 12 moons.

• Neptune (8 moons)Neptune (8 moons)• Triton revolves around Neptune in a retrograde Triton revolves around Neptune in a retrograde

orbit.orbit.

Pluto’s Moon

• Charon is 1/2 the size of Pluto Charon is 1/2 the size of Pluto • Some scientists consider them to be a Some scientists consider them to be a

double-planet system.double-planet system.• Charon orbit around Pluto = 6.4 dayCharon orbit around Pluto = 6.4 day• Pluto’s day (rotation) = 6.4 day Pluto. Pluto’s day (rotation) = 6.4 day Pluto. • Day = rotation means Charon stays in the Day = rotation means Charon stays in the

same place in Pluto’s sky.same place in Pluto’s sky.

Rings of the Gas Giants

• Saturn’s rings Saturn’s rings • discovered over 300 years agodiscovered over 300 years ago• Made of billions of pieces of rock and iceMade of billions of pieces of rock and ice

• Jupiter Jupiter • Thin ring made of microscopic particles given off Thin ring made of microscopic particles given off

by Io.by Io.• Uranus has a dozen thin rings.Uranus has a dozen thin rings.• Neptune’s relatively small number of rings are Neptune’s relatively small number of rings are

clumpy rather than thin and uniform.clumpy rather than thin and uniform.