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18 Cards in this Set
- Front
- Back
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How does the size of the moon compare to the size of the United States?
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The moon's diameter is less than the distance of the U.S. (3476 km)
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The gravity at the surface of the moon is only about ___ as great as the Earth's.
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1/6
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Because of the moon's ___ escape velocity, the moon's atmosphere is negligible.
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low
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Name one way that scientists knew the moon did not have an atmosphere before they visited it.
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The moon passed in front of a star, the star did not gradually dim, but blinked out abruptly
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How do astronomers believe most craters were formed?
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by impacts by meteoroids bombarding the surface
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How do geologists theorize that craters with low walls were formed?
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gases from molten rock are released then the gases expand explosively in the thin atmosphere, blasting away surface material and on the surface, a crater is formed
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What does waxing mean?
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gradually increasing in size, number, strength, and intensity
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What does waning mean?
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gradually decreasing in size, number, strength and intensity
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What is a solar eclipse?
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when the moon passes between the Earth and the sun blocking some light from the sun to the Earth
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How many times a year does a solar eclipse occur?
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two to three times a year
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How much of the Earth's surface is affected?
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never more than 150 miles
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True or False- You should take special precautions when viewing a solar eclipse and never look directly at it?
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True
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True or False- Most people go through life without witnessing a total eclipse firsthand?
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True
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What is a lunar eclipse?
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When the Earth is cutting off light from the sun that normally reaches the moon
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When is the only time that a lunar eclipse can be seen?
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during a full moon
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True or False- It is hard for astronomers to know when a lunar eclipse will happen?
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False
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True or False- You should take special precautions when viewing a lunar eclipse and never look directly at it?
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False
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What color is the moon during the lunar eclipse?
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coppery-red due to the red's long wavelength
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