Kepler's laws of planetary motion explaining how the planets' speeds varied, and using elliptical orbits rather than circular orbits with epicycles. Isaac Newton showed in 1687 that relationships like Kepler's would apply in the Solar System to a good approximation, as a consequence of his own laws of motion and law of universal gravitation. Kepler's laws improved the model of Copernicus. If the eccentricities of the planetary orbits are taken as zero, then Kepler basically agreed with Copernicus: The eccentricities of the orbits of those planets known to Copernicus and Kepler are small, so the foregoing rules give fair approximations of planetary motion, but Kepler's
Clarke's three laws same time. Clarke's first law was proposed in the 1962 edition of the essay, as "Clarke's Law" in "Profiles of the Future". The second law is offered as a simple observation in the same essay but its status as Clarke's second law was conferred by others. It was initially a derivative of the first law and formally became Clarke's second law where the author proposed the third law in the 1973 revision of "Profiles of the Future," which included an acknowledgement"." It was also here that Clarke wrote about the third law in these words: "As three laws were good