Transcript The Moon

The Moon
Formation & Earth-Moon
System
Earth's Moon
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3475 kilometers (2150 miles) in diameter
Similar to Earth's crustal rocks
Gravitational attraction is one-sixth of Earth's
No atmosphere
Earth's Moon
Lunar Surface
• Maria (mare sing.) Latin for sea
• Dark regions
– solidified lava flows
• Lowlands with fewer craters
Lunar Surface
• Highlands
• Bright areas, many craters
• Make up all of the "back" side of the Moon
• Older than maria
Lunar History
• The impact theory of the moon's formation
• Earth's moon formed from a collision between
the early Earth and a Mars-sized object.
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http://www.classzone.com/books/earth_science/terc/content/visualizations/es2501/es2501
page01.cfm?chapter_no=visualization
Phases of the Moon
• The Moon orbits Earth in a counter-clockwise
direction
• The positions of the Sun, Earth & Moon are
constantly changing
• Lunar phases result from the motion of the
Moon and the sunlight that is reflected from
its surface.
Phases of the Moon
Phases of the Moon
Click on the picture to begin the animation. Click again to pause.
Phases of the Moon
• Check out this page for definitions of each of
the different lunar phases.
– http://aa.usno.navy.mil/faq/docs/moon_phases.php
• Be sure to watch the Lunation movie at the
bottom of the page.
Phases of the Moon
• How long does it take for the Moon to
complete one revolution around the Earth?
• 27 days
Phases of the Moon
• Why do you see the same side of the moon?
• The Moon’s period of rotation = it’s period of
period of revolution (27 days)
• The same lunar hemisphere always faces Earth