Newton discovered gravity when an apple fell on his head while he was dozing under a tree. When Italian researcher Galileo dropped a heavy object and a light object from a tower in the 17th century, they both hit the ground at the same time, proving that the pull of gravity does not depend on weight. But if he had done this experiment during different seasons of the year and compared the results, he would have discovered that, while both objects took the same time to reach the ground, they got there at different speeds during different seasons of the year!
In New Scientist, Marcus Chown quotes physicist Alan Kosteleck
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