A look at our nearest neighbor in Space!

1
The Moon

• A look at our nearest neighbor in Space!

Free powerpoints at http//www.worldofteaching.com
2
What is the Moon?

• A natural satellite
• One of more than 96 moons in our Solar System
• The only moon of the planet Earth

3
Location, location, location!

• About 384,000 km (240,000 miles) from Earth
• 3,468 km (2,155 miles) in diameter (about ¼ the
  size of Earth)

4
Theories for Origin of Moon

• Fission originally part of Earth but torn free
• Problem would have fallen back or been flung
  into space, not into orbit.
• Fails to explain why lunar chemistry differs from
  Earth's
• Co-Creation formed in its present orbit
• can not explain why lunar chemistry differs from
  Earth's
• Capture formed as a separate planet but captured
  by Earth
• Conditions for successful capture very stringent
• Impact formed from Mega-Impact of Mars-sized
  planet
• Computer modeling suggests SS forms 100 or so
  small planets, then collide to make larger
  objects
• can explain differences in chemistry
• impact occurred after chemical differentiation in
  Earth therefore, not as much iron was part of
  the Moon
• high temperatures during impact would have
  vaporized the volatile and water vapor in rocks
• Currently favored model

5
Birth of the Moon

• Born 4-5 billion years ago
• Formed from impact of Mars-sized planetesimal
  on Earth
• Debris from both objects melted together to form
  the Moon

6
Computer Simulation of Formation of Moon

• Moon may have
• formed by a
• Mars-sized object
• impact on Earth
• Some of the material
• does not fall back
• onto the Earth, but
• forms a satellite
• of Earth

7
Cut to the Core

• 3 major divisions of the Lunar interior
• Crust - average thickness of about 70 kilometers
• Mantle
• Core - radius is between 300 and 425 kilometers

8
Moons interior structure
crust is thicker on non-Earth facing side

• iron-rich core like Earth
• asthenosphere layer somewhat pliable plastic
  layer
• solid layer just below surface no plate
  tectonics
• smaller planet than Earth less internal
  energy, less geological activity!
• moon probably had a weak magnetic field early in
  history
• - core is now solid, so no current is generated

9
Moonquakes Studying the Moons Interior

• 3000 quakes/year
• much lower intensity
• than Earth 0.5-1.5 Richter
• indicate that Moons
• interior is more rigid than
• Earths (some plasticity)

Seismometer placed on Moon by lunar astronauts
10
The Moons Surface

• No atmosphere
• No liquid water
• Extreme temperatures
• Daytime 130?C (265F)
• Nighttime -190?C (-310 ?F)
• 1/6 Earths gravity

11
Lunar Features - Highlands

• Mountains up to 7500 m (25,000 ft) tall
• Rilles (trenchlike valleys)

12
Lunar Features - Craters

• Up to 2500 km (1,553 miles) across
• Most formed by meteorite impact on the Moon
• Some formed by volcanic action inside the Moon

13
Lunar Geological Features

• Craters
• 30,000 visible with small telescopes from Earth
• millions visible from lunar orbiting satellites
• origin interplanetary debris
• sizes largest 100s km
• across a result of fast
• moving impact rocks
• of only a few kms across!
• large craters often
• produce central peak
• craters

Clavius Crater diameter 232 km depth of 16,000
feet
14
Lunar Features - Maria

• Originally thought to be seas by early
  astronomers
• Darkest parts of lunar landscape
• Filled by lava after crash of huge meteorites on
  lunar surface 3-4 billion years ago
• Mostly basalt rock

15
Limb
Terminator
16
Craters
Can you see the rays?
Maria
Does this photo show us a limb or terminator line?
17
Color-coded images illustrate surface geography

• Galileo data flyby in 1989
• blue lowland marias
• red - highlands

18
Movements of the Moon

• Revolution Moon orbits the Earth every 271/3
  days
• The moon rises in the east and sets in the west
• The moon rises and sets 50 minutes later each day
• Rotation Moon turns on its axis every 27 days
• Same side of Moon always faces Earth

19
Moon Rocks Sampling the Surface of the Moon

• surface material regolith
• pulverized by constant impacts
• 2500 samples brought back
• by astronauts 850 lbs total!!
• all rocks are IGNEOUS (i.e.,
• from molten processes)
• totally dry rocks (no water)
• all rocks older than 3 Byr

20
Far Side of the Moon

• First seen by Luna 3 Russian space probe in 1959
• Surface features different from near side
• More craters
• Very few maria
• Thicker crust

21
Its Just a Phase

• Moonlight is reflected sunlight
• Half the moons surface is always reflecting
  light
• From Earth we see different amounts of the Moons
  lit surface
• The amount seen is called a phase

22
Waxing and Waning

• New moon
• Waxing Crescent moon
• First Quarter moon
• Waxing Gibbous moon
• Full moon
• Waning Gibbous moon
• Third Quarter moon
• Waning Crescent moon
• New moon

23
FOUR MAIN SHAPES
Four Basic Shapes
FULL
CRESCENT
GIBBOUS
QUARTER
24
(No Transcript)
25
Rising/Meridian/Setting Times
Phase Rising Meridian Setting
New 6 am Noon 6 pm
Waxing Crescent 9 am 3 pm 9 pm
First Quarter Noon 6 pm Midnight
Waxing Crescent 3 pm 9 pm 3 am
Full 6 pm Midnight 6 am
Waning Gibbous 9 pm 3 am 9 am
Third Quarter Midnight 6 am Noon
Waning Crescent 3 am 9 am 3 pm
Assuming the moon is always on the celestial
equator and above the horizon 12 hours per day.
26
Earth
Plane of earths orbit
Moon
Plane of lunar orbit
Moon
27
Lunar Eclipses

• Moon moves into Earths shadow this shadow
  darkens the Moon
• Umbra
• Penumbra
• About 2-3 per year
• Last up to 4 hours

28
Solar Eclipses

• Moon moves between Earth and Sun
• Moon casts a shadow on part of the Earth
• Total eclipses rare only once every 360 years
  from one location!

29
The Tides

• Tides caused by pull of Moons gravity on Earth
• High tide
• Side facing Moon and side away from Moon
• Every 12 hours, 25 ½ minutes
• Low tide
• On sides of Earth

30
Exploring the Moon

• 1950s to 1960s - probes
• Neil Armstrong First man on the Moon July
  20, 1969
• Six Apollo missions (1969-1972)
• 382 kg (842 lbs) rocks
• 12 Americans have walked on the moon

31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37
(No Transcript)
38
(No Transcript)
39
(No Transcript)
40
When will we return?
41
Ice on the Moon?

• 1994 Clementine probe
• 1998 Lunar Prospector

42
Moon base of the future?

• What would you need to live there?

43
(No Transcript)
44
(No Transcript)
45
The Lunar Challenge!
46
Name this phase!
Full Moon
What time does this phase rise and set?
47
Name these features.
Craters
Maria
Name these features.
48
Does this image show us the near side or far side
of the moon?
Far Side
How can you tell?
49
Is this line the limb or terminator?
Limb
Terminator
Is this line the limb or terminator?
50
Name this phase!
First Quarter
51
Name this phase!
Waxing Crescent
52
Does this image show the near side or the far
side of the moon?
Near Side
53
Name this phase!
Waning Gibbous
54
Name this phase!
Third Quarter
55
From what direction does the moon rise?
The East
56
Name this phase!
Waxing Gibbous
57
Name this phase!
Waning Crescent
58
What might be happening in this image?
Lunar Eclipse
59
Is this line the limb or the terminator?
Limb
60
Name this phase!
Look closely!
Waxing Gibbous
61
True or False The Far Side and the Dark Side of
the moon are the same thing.
False!
62
Name this phase!
Full Moon
63
Name this phase!
New Moon
64
Does the moon rise or set in the west?
It sets in the west.
65
Name this phase!
Waning Gibbous
66
Name this phase!
Waning Crescent
67
Name this phase!
Waning Gibbous