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23.2 The Inner Planets (Terrestrial)
I.
Mercury
A. Closest to the Sun (0.4 AU)
B. 2nd smallest planet
C. Shortest orbit (1 year = 88 days)
D. 1 Mercury Day = 59 days
E. Temperature = from ‐180°C to 425°C F. Many impact craters, basins, and rilles
G. Most were created from meteor bombardment during the formation of the solar system
II. Venus
A. Stats (Statistics)
1. 2nd from the sun (0.7AU)
2. Orbit (1 Venus year) = 225 days
3. Retrograde Rotation = spins the opposite direction
4. 1 Venus day = 243 Earth days
5. Nearly the same size as Earth
6. Extremely weak magnetic field
B. Atmosphere
1. Always covered by thick clouds (Impossible to see the surface)
2. Little water vapor in clouds = Mostly CO2 and sulfuric acid!
3. RUNAWAY Greenhouse Effect making it the hottest planet (475 °C) C. Surface Features
1. Mountains & Canyons
2. Volcanoes (recent activity?)
3. Evidence of Plate Tectonics III. Earth
A. Third planet from the Sun
B. Densest and fifth‐largest of the eight planets in the Solar System
C. Largest of the Solar System's four terrestrial planets
D. A.K.A. – the World or the Blue Planet.
IV. Mars
A. Stats
1. 4th planet (last terrestrial planet)
2. Rotation (1 day) = 24 hours 37 minutes
3. Orbit (1 year)= 687 days
4. Approximately 1/3 the size of Earth
B. Atmosphere
1. reddish‐brown color due to blowing dust & rocks
2. atmosphere with clouds – mainly CO2 w/ N and Ar
3. seasonal polar ice caps made of CO2 & frozen water
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C. Surface Features
1. Many mountains & canyons ‐ Valles Marineris
2. Biggest volcano in the solar system ‐ Olympus Mons
3. NO tectonic plate activity has been noted.
D. Moons (2)
1. Phobos & Deimos
2. Not spherical 3. Large asteroids
23.3 Outer Planets (Gas Giants)
V. Jupiter
A. Stats
1. Largest Planet 2. 318 x’s mass of Earth
3. 2 ½ x’s more massive than all other planets combined
4. 5th Planet (5.2 AU)
5. Rotation (1 day) = 9 hours 55 minutes
6. Orbit (1 year) = 11.9 years
7. Massive magnetic field 8. 16 moons & one faint ring 9. May have been a 2nd sun if it had been larger
B. Atmosphere
1. mostly H & He
2. Gives off more heat than it receives from the Sun
3. Colorful bands, high winds
a) Light colored bands = zones
b) Dark colored bands = belts
4. Many storms
5. The Great Red Spot
a) Driven by Jupiter’s internal energy
b) Has existed for at least 400 years!
VI. Saturn
A. Stats
1. 2nd most massive planet
2. Rotation (1 day) = 10–11 hours 3. Orbit (1 year) = 29 years 6 months
4. Lowest density of any planet
–It would float in water!
5. Elaborate Ring System
–Chunks of ice and rock
6. Very large magnetic field, but weaker than Jupiter’s
B. Atmosphere
1. He & H gas
2. Gives off more heat than it receives
3. Storms & high‐velocity winds C. Complex Ring System
1. made up of mostly ice & rock 2. only 10km thick
3. Rings are NOT uniform
4. “spokes” have been found
VII. Uranus
A. 7th planet (19.2 AU)
B. 1st planet discovered in “modern times” (1781)
C. Spins through space on its side!
D. Rotation (1 day)= 17 hours
E. Orbit (1 year)= 84 years
F. Rings and 21 Moons
G. Atmosphere mostly of H & He
H. Generally featureless
I. Blue color from methane gas
J. Magnetic field is not on the same axis as its poles!
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VIII. Neptune
A. Stats
1. Highly elliptical orbit (30 AU at max!)
2. At times our most distant planet
3. Rotation = 16 hours 4. Orbit = 165 years 5. Faint ring system
6. 8 moons
B. Atmosphere = H, He, & methane
1. methane give it the bluish color (p.597)
2. Storms = Wind speeds of 730 mph
3. The Great Dark Spot (similar to Jupiter’s)
IX. **Pluto
A. Dwarf planet B. 2/3 the size of the Moon
C. Rotation = 6 ½ days D. Orbit = 165 years & highly elliptical
E. Little atmosphere & very cold temp.s
F. 1 Moon = Charon
– Nearly the same size as Pluto!
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