The Moon
Lunar Surface/Characteristics/OriginLunar Motion
The Moon
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Lunar Features - HighlandsMountains up to 7500 m (25,000 ft)
tallRilles (trenchlike valleys)
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Lunar Features - CratersUp to 2500 km (1,553 miles) acrossMost
formed by meteorite impact on the MoonSome formed by volcanic
action inside the Moon
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Crater Impact Animation
Lunar Features - MariaOriginally thought to be seas by early
astronomersDarkest parts of lunar landscapeFilled by lava after
crash of huge meteorites on lunar surface 3-4 billion years
agoMostly basalt rock
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Maria
Craters
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Far Side of the MoonFirst seen by Luna 3 Russian space probe in
1959
Surface features different from near sideMore cratersVery few
mariaThicker crust
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Ice on the Moon?1994 Clementine probe1998 Lunar Prospector
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The Moons SurfaceNo atmosphereNo liquid waterExtreme
temperaturesDaytime = 130C (265F)Nighttime = -190C (-310 F)
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Birth of the MoonBorn 4-5 billion years agoFormed from impact of
Mars-sized planetesimal on EarthDebris from both objects melted
together to form the Moon
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The Origin of the Moon
Cut to the Core3 major divisions of the Lunar interiorCrust -
average thickness of about 70 kilometersMantleCore - radius is
between 300 and 425 kilometers
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The moon is essentially a chunk of Earth that broke off during a
collision a long time ago. The moon is as old as Earth ~4.6 billion
years old.Earths only natural satelliteThe Moon
Distance to Moon 30 Earth DiametersEarths closest Neighbor
About 384,000 km (240,000 miles) from Earth
Gravity is 1/6th that of EarthA 100lbs. person would weight
18lbs. on the moon.
Barycenter
The Earth and the Moon together make a system; The Earth Moon
System.Although it appears that the moon orbits the Earth, the moon
actually orbits a common center of gravity between the Earth and
the moon.This common center of gravity is referred to as the
barycenter.Both the Moon and the Earth move about this center of
gravity.It is this point that revolves around the sun.This point is
located 900 miles from Earths surface.
EARTH MOON BARYCENTER VIDEO
Explain how the Earth and Moon act as a system. In other words
what is the barycenter and how does the moon revolve around
Earth?Student Response Response 3!
The man on the moon!
The Dancing Women Around a Tree on the Moon
The moon is in a synchronous orbit around Earth.The moon is in a
tidal lock with the Earth.What is different about these
pictures?
Tidal Locked Moon
The moon revolves and rotates at the same timeWe always see the
same side of the moon!
Explain why there is a big difference between the appearance of
the far side and near side of the moon.Student Response Response
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The moon rotates and revolves once around the Earth every 27.3
Earth days.
Remember, as the moon is revolving around Earth, Earth is also
revolving around the sun. Moon goes through one cycle of phases in
29.5 days, an extra 2.2 days for the Moon to make up Earths
revolution.The Moons RevolutionBut it does not complete the lunar
phase cycle for 29.5 daysWHY THE EXTRA TIME?
Sidereal Month The time it takes the moon to complete 1
revolution. Time = 27.3 Earth Days.
Synodic Month The time it takes the moon to go from New Moon
Phase to the start of the next New Moon Phase.Time 29.5 Earth
Days.The Lunar Cycle 2 ways to look at it!
Explain why the Synodic Month is longer than the Sidereal Month;
why the moon has to travel farther than 360 to go through all of
its phases as seen from Earth. Student Response Response 1
Movements of the MoonRevolution Moon orbits the Earth every 27.3
daysLunar Cycle takes 29.5 daysThe moon rises in the east and sets
in the westThe moon rises and sets 50 minutes later each
dayRotation Moon turns on its axis every 27 daysSame side of Moon
always faces Earth
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EarthMoonMoonPlane of earths orbitPlane of lunar orbit
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