CHAPTER 25 EARTHS MOON

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CHAPTER 25EARTHS MOON
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ORIGINS AND PROPERTIES OF THE MOON

• THEORIES OF THE ORIGIN OF THE MOON
• 1. SIMULTANEOUS THEORY
• 2. SPINNING TOO FAST THEORY
• 3. CAPTURE THEORY
• ACCEPTED THEORY
• 4. IMPACT THEORY

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IMPACT THEORY

• MOON FORMED 4.5 BYA AS A RESULT OF A COLLISION
  BETWEEN EARTH AND A PLANET-SIZED OBJECT

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(No Transcript)
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• http//www.classzone.com/books/earth_science/terc/
  content/visualizations/es2501/es2501page01.cfm

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DEVELOPMENT OF THE MOON

• AFTER THE IMPACT
• DEBRIS STARTED ORBITING THE EARTH
• GRAVITY PULLED THE DEBRIS TOGETHER
• ADDITIONAL IMPACTS OCCURRED MELTING THE SURFACE
  FORMING A MAGMA OCEAN

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MOON DEVELOPMENT

• 4. LIGHTER MATERIAL FLOATED TO THE TOP
• 5. CRUST COOLED AND HARDENED
• 6. ADDITIONAL IMPACTS OCCURRED CAUSING CRATERS TO
  FORM
• 3 TO 4 BILLION YEARS AGO THE IMPACTS SLOWED DOWN

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MOON TODAY

• MOSTLY MICROMETEORIODS HIT THE MOON NOW
• THE LAVA HAS COOLED AND FORMED FLAT PLAINS
• THE MOON IS GEOLOGICALLY INACTIVE

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LAYERS OF THE MOON
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PROPERTIES AND FEATURES OF THE MOON

• THE MOON TURNS ONCE ON ITS AXIS IN THE SAME TIME
  IT TAKES TO ORBIT AROUND THE EARTH ONE TIME
• THAT IS WHY WE ONLY SEE ONE SIDE OF THE MOON

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MOON FACTS

• DIAMETER 3476 KILOMETERS
• MASS 1/80TH OF THE EARTH
• DENSITY 3.3 g/cm3
• LIGHT AREAS OF THE MOON LUNAR HIGHLANDS
• DARK AREAS GREAT BASINS AND LEVEL PLAINS
• MARIA (LATIN FOR SEAS) BASINS, FIRST THOUGHT TO
  HAVE BEEN FILLED WITH WATER

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LUNAR MARIA

• MOON ROCKS ARE IGNEOUS
• MOST RESEMBLE BASALTS AND ARE FINE GRAINED
  CRYSTALLINE ROCKS
• DARK GRAY OR BLACK
• MARIA BASALTS ARE THE YOUNGEST LUNAR ROCKS 3.1
  TO 3.8 BYA
• MASCONS AREAS OF HIGHER GRAVITY ON SURFACE
• RILLES TRENCHLIKE VALLEYS RUNNING THROUGH MARIA
  BEDROCK
• FORMED WHEN LAVA FLOWS COOLED AND CAVED IN

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LUNAR HIGHLANDS

• APPEAR BRIGHTER THAN THE MARIA
• ROCKS ARE LIGHTER AND REFLECT MORE SUNLIGHT
• MOST MOUNTAIN RANGES ARE AT THE EDGES OF THE
  MARIA
• MARE IMBRIUM GREAT MOUNTAIN RANGE
• INCLUDES LUNAR ALPS, APENNINES, AND CAUCASUS
  MOUNTAINS

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LUNAR MOUNTAIN RANGES

• SOME PEAKS ARE AS TALL AS 5 KILOMETERS
• HIGHLAND ROCKS ARE BETWEEN 4.0 AND 4.3 BILLION
  YEARS OLD
• SOME ARE AS OLD AS 4.5 BILLION YEARS OLD

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LUNAR CRATERS AND RAYS

• CRATERS CIRCULAR HOLLOWS ON SURFACE
• RANGE FROM MICROSCOPIC IN SIZE TO 2100 METERS
  ACROSS
• RIMS ARE RUGGED CLIFFS
• RAYS RADIATE FROM CRATERS AND APPEAR TO BE MANY
  KM LONG, SPLASHED OUT BY METEORIODS

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LUNAR SOIL

• NOT REALLY SOIL LIKE ON THE EARTH
• CALLED REGOLITH
• LOOSE ROCK MATERIAL THAT IS GREY TO BROWN IN
  COLOR
• RANGES FROM 2 TO 20 METERS THICK

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SURFACE OF THE MOON
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MOONS MOTIONS

• MOONS ORBIT
• RISES IN THE EAST, SETS IN THE WEST
• TAKES ABOUT 27 1/3 DAYS
• WHEN THE MOON IS ON THE SIDE OF THE EARTH
  OPPOSITE THE SUN IT IS SEEN MOSTLY AT NIGHT
• WHEN THE MOON IS BETWEEN THE SUN AND THE EARTH IT
  IS SEEN MOSTLY DURING THE DAY

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MOONS ORBIT

• ORBIT IS ABOUT 5 DEGREES DIFFERENT FROM THE PLANE
  OF EARTHS ORBIT
• MOON RISES ABOUT 40 TO 50 MINUTES LATER EVERY DAY
• MOON MOVES IN AN ELLIPTICAL ORBIT AROUND THE
  EARTH
• AVERAGE DISTANCE FROM THE EARTH 384,000 KM
• CLOSEST PERIGEE
• FARTHEST APOGEE

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MOONS PHASES

• PHASES ARE THE DAILY CHANGES IN THE MOONS
  APPEARANCE
• WE SEE PHASES BECAUSE
• WE SEE THE REFLECTION OF THE SUNLIGHT OFF THE
  SURFACE
• THE MOON IS IN ORBIT AROUND THE EARTH

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PHASES OF THE MOON
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PHASES

• WAXING NEW MOON TO FULL MOON
• WANING FULL MOON TO NEW MOON
• CRESCENT ONLY ONE EDGE IS VISIBLE
• QUARTER HALF THE MOON IS VISIBLE
• GIBBOUS OVER A QUARTER IS VISIBLE

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MOONS PHASES

• http//www.classzone.com/books/earth_science/terc/
  content/visualizations/es2503/es2503page01.cfm

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PHASES OF THE MOON

• NEW MOON
• WAXING CRESCENT
• FIRST QUARTER
• WAXING GIBBOUS
• FULL MOON
• WANNING GIBBOUS
• LAST QUARTER
• WANING CRESCENT
• NEW MOON

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ECLIPSES

• LUNAR ECLIPSE
• EARTHS SHADOW PREVENTS THE SUNLIGHT FROM
  REACHING THE MOON
• CAN ONLY OCCUR DURING THE FULL MOON PHASE
• MOON USUALLY TURNS ORANGE-RED COLOR BECAUSE OF
  THE LIGHT PASSING THROUGH THE EARTHS ATMOSPHERE

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ECLIPSES

• SOLAR ECLIPSE
• WHEN THE MOON COMES BETWEEN THE SUN AND THE EARTH
  AND THE MOONS SHADOW HITS THE EARTH
• OCCURS ONLY DURING THE NEW MOON PHASE
• HAPPENS AT LEAST ONCE A YEAR BUT THE PATH CROSSES
  DIFFERENT PARTS OF THE PLANET

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ECLIPSES

• UMBRA AREA OF TOTAL SHADOW
• PRENUMBRA AREA OF PARTIAL SHADOW
• TOTAL
• PARTIAL
• ANNULAR
• http//csep10.phys.utk.edu/astr161/lect/time/eclip
  se_anim.html

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LUNAR ECLIPSE
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LUNAR ECLIPSE