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Hello.
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When we look at the sky, we see stars moving in a pattern that is much less complicated than of planets.
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And that's because stars are distant.
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Stars are very distant compared to planets.
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Planets, as we know, are revolving around the sun, just like our planet is revolving around the sun.
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But when the first astronomers tried to look at the planets, they noticed something and they couldn't explain it.
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First, they have the geocentric model.
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The geocentric model places our planet earth at the center and all the planets, including the sun, revolves around in circles.
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But at some days when they watched the planets, they saw that the planets after moving a little, bit to a certain direction, maybe to the east, they come back and flip again moving west, and they couldn't explain it at first...