The Moon
Theories on moon’s creation
• The Fission Theory:
– Part of earth
– Thrown out due to extreme rotation
– Basin in Pacific Ocean
– Earth’s gravity pulled it in
– Composition resembles earth’s composition
• 2. Capture Theory –
– Moon made in solar system
– Came into contact with earth’s gravitational field
– Pulled into orbit around earth
• 3. Condensation Theory –
– both condensed from gases at the beginning of
the solar system
• 4. Giant Impact Theory – ( most believed)
– Small planet impacted earth after it was first
made
– Material was thrown into space
– Material congealed to make a small planetoid
– Earth’s gravity captured the small planetoid to
orbit earth
Moon rocks
Rocks made of basalt from
volcanic eruptions and
minerals, such as
plagioclase feldspar and
olivine,
No organic materials
It's gray with very fine
grained particles like sand
or even dust and
extremely dry because
there is no water on the
moon
Lunar Breccia
• These fragments are the
white pieces visible in
the rock and are
composed of feldspar.
• feldspar, pyroxene, and
olivine.
basalt
Moon’s orbit
• Ellipse
• Rotation rate: once
every 27.3 days
– This keeps one side of
the moon facing the
earth at all times
• Revolution rate:
– 27.3 days
Moon’s orbit
• Apogee – point in
moon’s orbit furthest
from earth
• Perigee – point in
moon’s orbit closest to
earth
Moon phases
• Waning moon – moon is
getting smaller
• Waxing moon – moon is
getting larger
• Length – 29.5 days
– Extra days from revolution
due to position of S E and
M to return to starting
position
• Tides – Rise and fall of
the sea level due to the
gravitational pull of the
moon and sun on the
earth’s waters and solid
crust.
•
- moon has a
greater effect due to its
distance to the earth.
Kinds of tides
• Spring tides – when the
sun and moon are both
on the same side of the
earth.
•
- high tides
• Neap tides – when the
moon and sun are at rt.
angles to each other
Gravitational pull is
against each other
Low tides
Since the moon moves around the Earth, it is
not always in the same place at the same time
each day. So, each day, the times for high and
low tides change by 50 minutes.
Causes of tides:
• 1. position of moon and sun to earth
• 2. gravitational pull of moon and sun on
earth’s waters
• 3. rotation of earth in and out of the waters
Moon’s light
• Moon light is light
reflected from the sun off
the moon’s surface.
• Libration: wiggling of
moon in its orbit
• b/c of this we see 59% of
the moon.
• http://www.youtube.com
/watch?v=3f_21N3wcX8
• Regolith – lunar soil
• On the Moon, regolith
occurs as a mixture of
powdery dust and
broken rock. Lunar
regolith is formed by
the impact
of meteorites on the
body’s surface.
• Lunar gravity = 1/6 of
earth
• Weight: pull of gravity on
an object.
• Mass: amt. Of matter in
an obj.
• Since the Moon is smaller,
and has much less mass,
it pulls with less gravity.
Lunar eclipse
• Moon passes into the
shadow of the earth
• Umbra – darkest part of
the shadow
–
complete eclipse
• Penumbra – lighter part
of the shadow
•
-partial eclipse
• Two lunar eclipses each
year
• Duration – 1 hour
• Solar eclipse when the
earth moves into the
moon’s shadow.
• Small area on earth in
umbra.
• Total eclipse in umbra
• Lasts 8 minutes
• Annular eclipse – when
• moon’s shadow does
not touch the earth’s
surface.
Solar eclipse
•
Moon features
• Mares – Lt. seas
• smooth dark areas on
moon
- lava flows
- youngest rocks
• Craters – depressions
made from impact of
meteors
• Copernicus
• Plato
• Crater Walls – surround
crater
• Chained craters –
craters joined together
• Rays – light colored
material extending
outward from crater
•
- splash material
from impact
• Rilles - Rilles are
trenches a few
kilometers wide and
hundreds of meters
deep. Straight rilles are
faults in the lunar crust
whereas sinuous rilles
are collapsed lava
tubes.
• Wrinkled ridges – found
in maria result from
cooling
• Domes – small swelling
on surface
•
- domed
volcanoes
•
- laccoliths
pushing upward
• Mountain rangesmountains on the moon
Slide A
Slide B
Slide C
Slide D
Slide E
S
L
I
D
E
F
Slide J
Slide G
S
l
i
d
e
H
Slide I
S
l
i
d
e
J