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Claudius Ptolemy made a model of the solar system. the model accounted for the motions of planets.
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Copernicus says the sun is the center of the universe.
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Galileo began his observation of Venus.
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She published a table of 25 different cepheid variable periods.
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Hubble spotted a star known as the Andromeda Nebula. Using Leavitt's techniques he showed the star was 1 million light years away.
