Chinese
Lunar
Rover
•  15Dec2013 First soft landing since 1976
•  Chinese lunar rover still functioning but can’t move
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Moon
1 light second= 17days in a 747= 4days in Apollo 11
Moon is ¼ Earth’s diameter= 1/64 Earth’s volume
BUT mass is 1/80 Earth’s mass so density 3.3gm/cc
Rock=3 so no/small iron core=9gm/cc
No Atmosphere
•  No Atmosphere => no
erosion by wind/water
•  No air to moderate so
Maximum temperature
+123C & min -233C
Surface Features: Mare (=sea)
•  Maria =Lowlands composed of dark basalt shown in blue
•  Far side of Moon has thicker crust so no mare
•  Lunar Highlands (Terrae): heavily cratered light colored
rock in green
Craters Copernicus and Tycho
•  Bowl shaped depressions caused by impacts
•  Rays, ejecta blankets, secondary craters
•  From ~100’s km across to microscopic
Impact Crater Formation
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Impactor has velocity 10 times rifle bullet
Releases energy 10 times equal mass of dynamite
Impactor vaporized when temperature reaches millions K
Shock wave forms shocked quartz found only in impacts
Rebound can launch rocks without destroying them
Largest Impacts - Mare Orientale
•  Few large and far more
small craters
•  Terminator separates day
from night where shadows
emphasize surface
roughness
Cratering History
of the Moon
•  Radioactive dating of Lunar
samples gives absolute age
•  Counting density of craters on
surface gives relative age
•  Older surfaces have more craters
•  Can be extended throughout solar
system
Lunar Dust
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Regolith = crushed rock/dust; depth of a few meters
Sharp edged black dust clings to suits -not like Earth dust
Erosion: micrometeorites erase boot prints in millions years
Breccias= rocks glued with glass from impacts
Water on the Moon?
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Regolith contains no H2O,
but
Few polar craters always in shadow
Impacted by LCROSS 2009
Dust/gas plume shows water, OH…
Important for future colonists?
Volcanism - Hadley Rille
•  150km long, 1.5km across, 300meters deep
•  Formed by flowing lava 3.3 billion years ago
•  Vesicular basalt from moon (gas bubbles)
Formation of the Moon
1.  Fission – Protoearth spun so fast that the moon
budded off - but wrong angular momentum
2.  Coformation (co-creation): formed near Earth
from nebula - but small iron core & low volatiles
3.  Capture: formed somewhere else- wrong oxygen
isotopes + hard to capture + no iron or volatiles
4.  Impact Theory=Collisional Ejection: Earth hit
by Mars sized asteroid
Impact Theory of Formation of Moon
•  Elapsed time is about 24 hours;
moon forms in a year
•  Earth ends up spinning once in 5
hours, moon in low orbit
•  Earth was differentiated so moon
is made from mantle material
•  Correct isotope ratio, no iron
core, volatiles evaporate,
•  Robin Canup’s simulation
“Eagle Has Landed”
•  Apollo 11 lands in Mare Tranquillitatis
•  Neil Armstrong & Buzz Aldrin
•  20 July 1969
“One Small Step”
•  Neil Armstrong 20 July 1969
Hammer and Feather
•  6 Moon missions &12 astronauts
•  A week to get there
•  Apollo 15 and Surveyor 3
Apollo 16
Moon Rover
Last Man on the Moon? 1972
•  Moon Rock at Cape Kennedy
Which if any, of the following is
incorrect?
a.  We know the Moon’s Maria are a younger terrain
since they have fewer craters than the highlands.
b.  Neil Armstrong first set foot on the moon 1969.
c.  The moon is smaller than the Earth so we would
expect it to have a cooler core.
d.  The density of the moon is less than the Earths’
so we expect it to have a smaller iron core
e.  All of these are correct
When did the first man,
Neil Armstrong, land on
the moon? 20 July ___
a)  1609
b)  1959
c)  1969
d)  1979
e)  1989
Fox TV •  No stars: Not enough exposure
Moon Hoax •  Illuminated astronaut: bright
background
•  Parallel shadows: topography
•  Flag waving: no atmosphere so
waved longer & liked it wrinkled
Late Heavy Bombardment
•  Late Heavy Bombardment second
surge in impacts
•  When Jupiter, Saturn, Uranus,
Neptune change orbits scattering
planetesimals?
Rocky Surfaces Saturated with Craters
•  Planets formed from
many meteorite impacts
•  Circular craters due to
explosion caused by
impact
•  Solar System “Full”?
Erosion of Craters
•  Craters hidden by:
1. Volcanoes – lava flows
2. Continental drift
3. Erosion by atmosphere
4. Oceans
Younger Terrain = Fewer Craters
•  The larger the terrestrial world; the more internal
heat it will retain = higher temperature in core
•  The higher temperature; more geologically active so
more craters are covered = fewer craters showing
•  Older terrains = more craters
Rotation of the Moon
•  Revolves & rotates on axis in
sidereal=27.3 d synodic=29.53d
•  Keeps one side facing the Earth =
synchronous orbit/rotation
•  Moon & Earth orbit center of mass
Internal Structure of the Moon
•  Seismic data from Apollo landers recording
moonquakes from tides
•  Crust is thicker ~60km than Earth’s ~10km
•  Mantle 80% radius
•  Core <25%
Impact Crater
•  All lunar craters seem to be impact
craters not volcanic – no plate tectonics
Giant
Impactor
•  Painting by Kaufmann
•  Problem of the low density of the Moon
•  Solved by Moon being formed from low density
mantle material
•  Is it Science? Testable Prediction = Disprovable
No Atmosphere = No Erosion
But Ice at Mercury’s & Moon’s Poles?
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VLA radar observations see echo from poles which resembles ice
Surface temperature 100K to 700K, but inclination of rotation axes 0º
South Pole of Moon with craters permanently in shadow in white
Hydrogen detected from neutron spectrometer on Lunar Prospector
Lunar Impact