earths moon

Earth’s Moon

Earth Science

1st Semester

• Most of the knowledge about the Moon comes from the Apollo Missions conducted by the Unites States between the years 1969 and 1972.

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• Some information that has been determined at this point is that the Moon has a density of 3.3 g/mL, while the Earth has a density of 5.5g/mL

• The difference is due to the Moon having a small iron core.

• As a result of its small mass the Moon has 1/16th the gravity of the Earth.

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The Lunar Surface

• The moon has no liquid water on its surface nor any form of an atmosphere.

• As a result, the Moon’s surface cannot be worn down by the action of moving wind and water, a process called weathering and erosion on Earth.

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• The Moon is not tectonically active right now, so volcanic eruptions do not occur any longer

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• Since the Moon has no atmosphere, particles from space continually bombard its surface, gradually smoothing out the landscape.

Craters

• The term used to describe round depressions in the surface of the moon.

• There are many, the largest being the width of the state of Indiana.

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• Craters are caused by the impact of rapidly moving meteoroids.

• Meteoroids are small solid particles of rock or metal that travel through space.

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• In contrast to the Moon, the Earth has very few recognizable craters on its surface. QuickTime™ and a

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• When meteoroids come through Earth’s atmosphere, the friction that is caused tends to burn most of them up.

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• The ones that do make it leave little evidence for us to examine today, as the forces of erosion, and plate movement have erased most of the craters.

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Formation of a Crater

• When a meteoroid strikes the surface of the moon, it will compress the material that it strikes.

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• There will be some rebound, where material is thrown back up from the new crater.

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• Most of this ejected material will land near the crater and build a rim around it.

• The heat generated by the impact is enough to melt rock into molten glass.

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• The larger craters on the Moon, like Kepler and Copernicus, are believed to be relatively young because of the bright rays or splash marks that radiate out form the crater.

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Highlands

• This moon landscape feature makes up most of the lunar surface.

• These densely pitted, light colored areas contain mountain ranges whose peaks reach as high as the Himalayas on Earth.

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Mare

• The term given to any dark, relatively smooth area on the moon’s surface. If there is more than one, they are called maria.

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• They were thought to have originated when asteroids were able to puncture the lunar surface, releasing magma from the interior.

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• Asteroids are relatively small, rocky bodies with a size from a few hundred kilometers to less than a kilometer.

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• Scientists have determined that the maria are comprised of a type of hardened lava known as basalt.

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• Scientists theorize that the material that fills the maria could be thousands of kilometers thick.QuickTime™ and a

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• A surface feature known as a rille is associated with maria.

• Rilles look very much like valleys or trenches.

• Scientists think they may be the remnants of ancient lava flows.

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Regolith

• Any lunar terrain will be covered with a layer of grey debris from the millennia of bombardment from meteorites.

• This soil like layer is called a lunar regolith.

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• It is composed of volcanic rocks, bead like glass, and really fine lunar dust. QuickTime™ and a

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• In portions of the Moon explored by astronauts, the lunar regolith was over three meters thick.QuickTime™ and a

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