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The Moon
Week 2 part 2
Thursday, January 13, 2011
Two ways to look at it
The Moon from the point of view of
Earthlings (phases)
The Moon as a solar system body (what the
astronauts saw)
Thursday, January 13, 2011
The formation of the moon:
Impact hypothesis
something large (same size
as Mars) hit Earth and
knocked off a chunk of
Earth’s mantle
Much of splattered Earth
coalesced into the moon
The Mars-sized something
was completely destroyed
and probably merged with
Earth’s core
Thursday, January 13, 2011
The formation of the moon:
Impact hypothesis
something large (same size
as Mars) hit Earth and
knocked off a chunk of
Earth’s mantle
Much of splattered Earth
coalesced into the moon
The Mars-sized something
was completely destroyed
and probably merged with
Earth’s core
Thursday, January 13, 2011
moon
How do we know?
Thursday, January 13, 2011
How do we know?
We’ve been there...
Thursday, January 13, 2011
How do we know?
We’ve been there...
observations
Thursday, January 13, 2011
explanation
How do we know?
We’ve been there...
observations
tested soil composition same as Earth’s mantle and
crust (mostly silicates)
Thursday, January 13, 2011
explanation
How do we know?
We’ve been there...
observations
tested soil composition same as Earth’s mantle and
crust (mostly silicates)
made “moonquakes” to
determine layers (mantle
layer very thick)
Thursday, January 13, 2011
explanation
How do we know?
We’ve been there...
observations
tested soil composition same as Earth’s mantle and
crust (mostly silicates)
made “moonquakes” to
determine layers (mantle
layer very thick)
see lots of craters and
some “maria”
Thursday, January 13, 2011
explanation
How do we know?
We’ve been there...
observations
explanation
tested soil composition same as Earth’s mantle and
crust (mostly silicates)
moon formed from molten
mantle of Earth
made “moonquakes” to
determine layers (mantle
layer very thick)
see lots of craters and
some “maria”
Thursday, January 13, 2011
How do we know?
We’ve been there...
observations
explanation
tested soil composition same as Earth’s mantle and
crust (mostly silicates)
moon formed from molten
mantle of Earth
made “moonquakes” to
determine layers (mantle
layer very thick)
see lots of craters and
some “maria”
Thursday, January 13, 2011
used to have liquid core
and had lava flows on
surface
How do we know?
We’ve been there...
observations
explanation
tested soil composition same as Earth’s mantle and
crust (mostly silicates)
moon formed from molten
mantle of Earth
made “moonquakes” to
determine layers (mantle
layer very thick)
see lots of craters and
some “maria”
Thursday, January 13, 2011
used to have liquid core
and had lava flows on
surface
now is geologically dead (no
more flows, no liquid
center?)
Fun facts
Mass 1/83 Earth’s mass
no magnetic field
radius 1/4 Earth’s radius
“tidally locked” always shows the same
face to Earth, so Earth
only visible from one
side of moon
gravity 1/6 Earth’s
gravity
no atmosphere
no water (but maybe a
little ice)
Thursday, January 13, 2011
yes, we really went
there
Earthlings’ point of view
Always see the same side
see different parts of the face
Thursday, January 13, 2011
month <- moon
exhibits phases extremely regular
(always takes the
same amount of
time to get back
to a given phase)
moon doesn’t shine
- only reflects
sunlight
moon orbits Earth
Thursday, January 13, 2011
Thursday, January 13, 2011
Who’s rotating?
Thursday, January 13, 2011
Which is the near side and which is the far side?
(ignore the size difference - the images came from 2 different places
online)
Thursday, January 13, 2011
Resources
http://www.braeunig.us/space/hoax.htm
http://www.xmission.com/~jwindley/
Thursday, January 13, 2011