The big question was and still is what causes the moon to be attracted to the earth and the earth to the sun and the sun to our galaxy? Why don't they just fly off into space? What attracts us and everything else to the earth? Why aren't we slung off with the speed of the earth's rotation being faster than the speed of sound at the equator? Even with Albert Einstein's general theory of relativity where he explains geometrically how gravity works a century ago, these questions are still being asked today.
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