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

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

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

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.

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

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.

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

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

UPDATE National Geographic Moon

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

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

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

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

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

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

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

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

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

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

How did this spherule come to be on the Moon?

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.

25.1 SECTION REVIEW PAGE 560 1-2 WITH QUESTIONS