Keplers Laws in Physics?
Kepler’s “Laws” are empirical deductions that he drew from Tycho Brahe’s observations of the planets. As such they really belong to the field of Astronomy, and applied in the first instance only to the Solar System. (However, after Newton EXPLAINED their theoretical basis, we realized that they applied to all orbital motion, with appropriate changes to various constants characterizing those separate cases.) Kepler’s original Laws of Planetarty Motion can be expressed as follows: 1. Planets orbit the Sun in ellipses, with the Sun at one focus of each ellipse. 2. A line drawn from the Sun to any given planet sweeps out equal areas in equal times. (Hence its name, the “Law of Areas.”) 3. The squares of the orbital periods of the planets are proportional to the cubes of their orbital semi-major axes. (The latter is half the length of their longest axis, the line through the two foci of each particular ellipse.) This Kepler called his “Harmonic Law.” Mathematically, the following equations
