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12 Cards in this Set
- Front
- Back
Solar System
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System of nine planets, and numerous other objects (moons, asteroids, comets) that orbit the sun, all held in place by the suns gravity.
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Astronomical Unit (A.U.)
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Unit of measurement that equals 150 million km, which is the mean distance from earth to the sun. astronomical units are used because of the great distances in space for example, 2 A.U. = 300 million kilometers
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Comet
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large body of frozen ice and rock that travels toward the center of the solar system, and develops a bright , glowing tail as it approaches the sun
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Meteor
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"Shooting stars" or metors are bits of material falling through Earth's atmosphere - usually burn up before reaching the Earth's surface.
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Meteorite
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Large pieces that do not vaporize completely and reach the surface of the Earth.
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Meteoroid
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Meteors or chunks as they are hurtling through space before they reach the atmosphere.
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Asteroid
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Rocky fragments left over from the formation of the solare system about 4.6 billion years ago
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Atmosphere
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The gases that surround a planet. Atmospheres help hold in some heat, so day and night temperatures are not radically different.
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Rotation
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Spinning of Earth on its axis, which occurs once every 24 hours, produces day and night, and causes the planets and stars to appear to rise and set.
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Revolution
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Movement of the earth around the Sun, which takes a year to complete 365.25 earth days.
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Eclipse
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Event that occurs wehn the Moon moves between the Sun and Earth (solar eclips), or when Earth moves between the Sun and the Moon (lunar eclipse), and casts a shadow
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Orbit
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Regular curved path followed by Earth as it moves around the Sun
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