1. 25.1 ORIGIN AND PROPERTIES OF THE MOON DAHS MR. SWEET
CHAPTER 25 EARTH’S MOON
25.1 ORIGIN AND PROPERTIES OF THE MOON
DAHS MR. SWEET

2. OBJECTIVES EXPLAIN VARIOUS HYPOTHESES ABOUT HOW THE MOON FORMED.
DESCRIBE THE FEATURES AND PROPERTIES OF THE MOON.

3. WHAT IS THE MOON? A NATURAL SATELLITE
ONE OF MORE THAN 96 MOONS IN OUR SOLAR SYSTEM
THE ONLY MOON OF THE PLANET EARTH

4. ORIGIN OF THE MOON
SCIENTIST BELIEVE THE MOON FORMED WHEN A LARGE OBJECT ABOUT THE SIZE OF A PLANET HIT EARTH.
3. The debris ring, made of rock from the outer layer of both objects, gradually coalesces, forming the moon.
2. The impact heats and deforms both bodies. Some rocky debris remains in orbit around Earth.
1. Earth is hit off-center by a planet-sized object.

5. DEVELOPMENT OF THE MOON
METEOROID IMPACTS MELTED MOONS SURFACE AND CREATED CRATERS
FORMED MAGMA OCEAN
LIGHTER MATERIALS ROSE TO SURFACE – COOLED AND HARDENED
4.0 – 3.5 BILLION YEARS AGO IMPACTS DECREASED
OVER MILLIONS OF YEARS MAGMA RICH IN IRON ERUPTED FILLING LARGE BASINS CREATING MARIA

6. Observe images illustrating the impact theory of the moon's formation.
YouTube - How the Moon was born!
Observe images illustrating the impact theory of the moon's formation.

7. MOON TODAY CORE INACTIVE
IMPACTS FROM MICROMETEOROIDS CONTINUE TO CHANGE SURFACE THROUGH IMPACTS AND EROSION
MOON HAS NO ATMOSPHERE TO BURN THEM UP

8. LAYERS OF THE MOON Mantle Near side crust (about 65 km thick)
Far side crust (about 150km thick)
Iron Core

9. UPDATE
National Geographic Moon

10. PROPERTIES AND FEATURES OF THE MOON
SAME SIDE OF THE MOON FACES EARTH - GEOSYNCHRONOUS ORBIT
ABOUT 384,000 km (240,000 mi.) FROM EARTH
3,476 km (2,155 miles) IN DIAMETER
ABOUT ¼ THE SIZE OF EARTH
DENSITY 3.3g/cm3
1/6 EARTH’S GRAVITY

11. FAR SIDE OF THE MOON
FIRST SEEN BY THE LUNA 3 RUSSIAN SPACE PROBE IN 1959
SURFACE FEATURES ARE DIFFERENT FROM THE NEAR SIDE
MORE CRATERS
VERY FEW MARIA
THICKER CRUST

12. THE MOON’S SURFACE NO ATHMOSPHERE NO LIQUID WATER EXTREME TEMPS.
DAYTIME = 130C (265°F)
NIGHTIME = -190C (-310 F)

13. MARIA ORIGINALLY THOUGHT TO BE “SEAS” BY EARLY ASTRONOMERS
DARKEST PARTS OF THE LUNAR LANDSCAPE
MOSTLY BASALT ROCK MADE OF FELDSPARS AND PYROXENE
YOUNGEST ROCKS
Maria

14. MASCONS MASCONS MEANS MASS CONCENTRATIONS AREAS IN MARIA WITH
HIGHER DENSITY ROCKS
HIGHER GRAVITY READINGS
DISCOVERED IN 1960’S

15. RILLES TRENCHLIKE VALLEYS RUNNING THROUGH MARIA
MAY HAVE FORMED FROM A RIVER OF LAVA
THE RIVER SURFACE HARDENED
THE LAVA DRAINED AWAY
THE SURFACE COLLAPSED
RILLE

16. HIGHLANDS MOUNTAINS UP TO 7,500 m (25,000 ft) TALL
THOUGHT TO BE THE ORIGINAL CRUST
FORMED FROM IMPACTS
LIGHTER IN COLOR THAN MARIA
ROCK SAMPLES SIMILAR TO GABBRO AND BRECCIA
ROCKS MADE OF ANGULAR FRAGMENTS
IMPACTS MELTED ROCKS TOGETHER

18. CRATERS CIRCULAR HOLLOWS FORMED BY METEOR IMPACTS
SIZE RANGE IS MICROSCOPIC TO 2100 km DIAMETER
MOST NAMED AFTER PEOPLE

22. RAYS CONSIST OF SHATTERED ROCK AND DUST
SPLASHED OUT BY METEROID IMPACTS
COPERNICUS IS 93 km CRATER WITH RAYS 100’S km LONG

23. LUNAR SOIL REGOLITH RANGE FROM FINE DUST TO SAND GRAINS 2 – 20 m DEEP
LOOSE ROCK MATERIALS
RANGE FROM FINE DUST TO SAND GRAINS 2 – 20 m DEEP
CONTAIN NO WATER OR ORGANICS
FORMEDY BY SMASHING IMPACTS OF METEORS
COMPOSED OF
ROCK AND MINERALS CHIPS
GLASSY BEADS

25. How did this spherule come to be on the Moon?

26. Explanation: When a meteorite strikes the Moon, the energy of the impact melts some of the splattering rock, a fraction of which might cool into tiny glass beads. Many of these glass beads were present in lunar soil samples returned to Earth by the Apollo missions. Pictured above is one such glass spherule that measures only a quarter of a millimeter across. This spherule is particularly interesting because it has been victim to an even smaller impact. A miniature crater is visible on the upper left, surrounded by a fragmented area caused by the shockwaves of the small impact. By dating many of these impacts, astronomers can estimate the history of cratering on our Moon.

27. 25.1 SECTION REVIEW
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