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CHAPTER 25 EARTH’S MOON 25.1 ORIGIN AND PROPERTIES OF THE MOON.

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Presentation on theme: "CHAPTER 25 EARTH’S MOON 25.1 ORIGIN AND PROPERTIES OF THE MOON."— Presentation transcript:

1 CHAPTER 25 EARTH’S MOON 25.1 ORIGIN AND PROPERTIES OF THE MOON

2 What is the Moon? A natural satellite One of more than 150 moons in our Solar System The only moon of the planet Earth

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4 ORIGIN OF THE MOON SCIENTIST BELIEVE THE MOON FORMED WHEN A LARGE OBJECT ABOUT THE SIZE OF A PLANET HIT EARTH YouTube - How the Moon was born!

5 DEVELOPMENT OF THE MOON SURFACE LAYERS MELTED BY FREQUENT IMPACTS 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 MOON TODAY CORE INACTIVE IMPACTS FROM MICROMETEOROIDS CONTINUE TO CHANGE SURFACE THROUGH IMPACTS AND EROSION MOON HAS NO ATMOSPHERE TO BURN THEM UP

7 PROPERTIES AND FEATURES OF THE MOON Same side of moon faces earth – geosynchronous orbit About 384,000 km (240,000 miles) from Earth 3,476 km (2,155 miles) in diameter (about ¼ the size of Earth) Density 3.3g/cm 3 1/6 Earth’s gravity

8 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

9 Layers of the moon Iron Core Near side crust (about 65 km thick) Mantle Far side crust (about 150km thick)

10 The Moon’s Surface No atmosphere No liquid water Extreme temperatures –Daytime = 130  C (265°F) –Nighttime = -190  C (- 310  F

11 Maria Originally thought to be “seas” by early astronomers Formed from lava coming up through cracks Darkest parts of lunar landscape Mostly basalt rock made of feldspars, pyroxene, youngest rocks

12 Maria

13 Mascons and Rilles Mascons are regions of higher gravity Rilles are long cracks in the maria

14 RILLE

15 Highlands Mountains up to 7500 m (25,000 ft) tall Thought to be original crust Formed from impacts Lighter in color than maria Rocks samples similar to Gabbro and Breccia – rocks made of angular fragments – impacts melted rocks together

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17 Craters and Rays Circular hollows formed by meteor impacts Range: microscopic to 2100 km diameter Most named after people Same age

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21 How did this spherule come to be on the Moon?

22 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.meteoriteMoonenergy of the impact splattering rockglass beads lunar soil samplesApollo missionsPictured abovespherulemillimeterspherule cratershockwavesdating impactsastronomers can estimate cratering

23 Copernicus crater rays

24 Lunar soil Regolith – loose rock material Range: fine dust to sand grains 2 – 20 m deep Contain no water or organics Formed by smashing impacts Composition – chips of varying minerals and glassy beads

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