The Moon

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The Moon
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What We See
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Where Weve Been
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The Big Features
Oceanus (ocean) Maria (Mare) (sea) Craters Highla
nds bright, cratered regions Lowlands/Maria
dark, flat regions
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Other Features
Mountains Valleys
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(No Transcript)
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Librations

• The result of
• wobbling of the Moons axis toward/away from
  earth
• Relative motion of the observer as Earth rotates
• Non-circularity of moons orbit (change in size)

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Whats it made of?
IamIRON MOON
Ti abundance (blue lots, orange/purple less)
Butno dipolar magnetic field. The moons weak B
field comes from magnetic minerals.
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The Real Dark Side of the Moon

• Note which side the maria are on.
• Why only that side?
• Anorthosite igneous rock rich in Ti, Fe
• Basalt fine-grained igneous rock caused by
  cooling magma

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Mascons
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Water?
1996 Clementine indicates ice in deep
craters 1998 Lunar Prospector indicates
ice 1998 LP crashed into surface no water
seen 2009 Moon Mineral Mapper aboard
Chandrayaan-1 detects water
Chandrayaan-1 (water in blue)
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LCROSS

• Launched with LRO in 2008
• Atlas-Centaur rocket impactor targeted Cabeus
  crater
• Impactor (2305 kg/10,000mph) produced ejecta
  plume
• LCROSS probe flew through the plume and crashed,
  relaying data
• Data indicate 5 of plume mass was water

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Where did the moon come from?

• 4 theories
• Fission (moon broke off from earth)
• Sisterhood/Co-accretion (formed at the same time)
• Capture (moon formed somewhere else but drifted
  by and ended up in the Earths gravitational
  field)
• Giant Impactor (something hit the earth and the
  resulting material formed the moon)

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Which one is right?

• Fission
• Composition of E and M are similar, but not that
  similar.
• Not enough mass in the Pacific Basin to account
  for the moon.
• 2. Sisterhood/Co-accretion
• See 1 about composition.
• E and M should be the same age M is younger.

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Which one is right?

• 3. Capture
• E and M are too similar for the moon to have
  formed elsewhere
• Angular momentum of the E/M system isnt right
  for the moon having flown in and stopped

• 4. Giant Impactor
• Given a Mars-sized impactor, mass is right
• Volatile metals and lack of water on the moon
  indicate high temperatures in the past.
• Simulations show its viable (angular momentum
  OK)
• Lower density of moon, lack of iron are
  consistent with violent impact

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Whack-a-Moon
t0

• Eventually, the cloud becomes a disk and then a
  moon.
• The impactor core becomes the moons core
• Intense heat is consistent with lack of volatiles
  and lack of similarity to the earth.

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