...of trouble, and was not published until 1619 in De Harmonices Mundi, Libri V, part 3. It states that the cubes of the semi-major axes of the planetary orbits are proportional to the squares of the planetary years. Note in particular the second law. Here one needs to find the area swept out in a...

...areas. Equation (3.8) will also be derived using Newtonian mechanics [3.1.2]. 3rd Law: The cubes of semi-major axes of the planetary orbits are proportional to the squares of the planet's periods of revolution In mathematical formulation this means for different planets P¡ with...

...change the axial direction of spin. Harmonic Law. Kepler's third law of planetary motion: the cubes of semimajor axes of the planetary orbits are proportional to the squares of the sidereal periods of the planets' revolutions about the Sun. Heavy bombardment. The period of time,...