He had been searching for this Third Law, that is to say, for a correlation between a planet’s period and its distance, since his youth. Without such a correlation, the universe would make no sense to him; it would be an arbitrary structure. If the sun had the power to govern the planets’ motions, then that motion must somehow depend on their distance from the sun; but how? Kepler was the first who saw the problem – quite apart from the fact that he found the answer to it, after twenty-two years of labour. The reason why nobody before him had asked the question is that nobody had thought of
...more
