Title: The Moon
1The Moon
2What We See
3Where Weve Been
4The Big Features
Oceanus (ocean) Maria (Mare) (sea) Craters Highla
nds bright, cratered regions Lowlands/Maria
dark, flat regions
5Other Features
Mountains Valleys
6(No Transcript)
7Librations
- 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)
8Whats 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.
9The 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
10Mascons
11Water?
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)
12LCROSS
- 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
13Where 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)
14Which 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.
15Which 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
16Whack-a-Moon
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- 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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