Transcript Planets

Planets
Types of Planets
• Inner (Terrestrial)
– Small
– Rocky
– Closer to sun (faster
orbits)
– Thin atmospheres
• Outer (Jovian)
– Very large
– Thick atmosphere (H,
He, methane)
– Distant from sun
(longer orbits)
– Rings
Photos from: http://photojournal.jpl.nasa.gov/index.html
Mercury
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88 day revolution
59 day rotation
Very small
Weak mag. Field.
Day: 400 °C;
Night: -200 °C
• Little to no atmosphere
• No moons
Venus
• 225 day revolution
• 243 day rotation (1 day is
longer than 1 year)
• Dense Atmosphere (CO2,
Sulfuric acid)
– Intense greenhouse effect
• 475 °C day temp (hottest
planet)
• No moons
Earth
• 365 day year
• 24 hr. day
• Temp allows for
s, l, g water
• 1 moon
Mars
• 687 day revolution
• ~24 hr day
• Tilt is similar to Earth’s = 4
seasons
• Weak or no magnetic field
• Day: 27 °C; night: -127 °C
• Mt. Olympus – largest
volcano in Solar System ,
26 km tall, extinct
• 2 moons
Meteorites/Asteroid
• Small rocky objects
• Commonly found between
Mars and Jupiter
• 10’s of thousands are known
• Most are the size of pebbles
and are spaced far apart
• ~220 are > 100 km across
• Up to 1,000,000 are expected
to be in orbits that may cross
Earth’s
Gaspra
Ida
Known
positions of
asteroids in
the inner
Solar
system
Jupiter
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Largest planet
11.9 year revolution
~10 hr. rotation
Strong magnetic field – solid or
liquid ‘core’
• Radiates more heat to space
than it receives.
• Great Red Spot – severe storm
system
• 62 (!) moons
Saturn
• 30 year revolution
• ~10 hr. rotation
• Lowest density of all planets
– Less than 1.0 g/cm3  would float in water
• Weaker magnetic field than Jupiter
• Spectacular Ring System
• 33 (!) moons
Uranus
• 84 year revolution
• 17.2 hr. rotation
• -200 °C surface
temperature
• Tilted on side,
magnetic field is
not
• 27 moons
Neptune
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165 year revolution
16.1 hr. rotation
-225 °C surface temp.
Methane gives blue
color
• Also tilted on side
• Sometimes 9th planet
(if Pluto’s orbit comes
inside Neptune’s)
• 13 moons
Pluto
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9th (or 8th) planet
248 year revolution
6.3 day rotation
Smallest – only 2800 km diameter
– Smaller than Earth’s moon
• -235 to -210 °C temperature
– Frozen atmosphere
• 1 moon