Example image of eyePlorer eyePlorer map for 'Kepler's laws of planetary motion': Astronomy Ellipse Focus (geometry) Orbit Planet Line (geometry) Cube (algebra) Orbital period Proportionality (mathematics) Semi-major axis Square (algebra) Astronomer Germans Johannes Kepler Mathematician Solar System Observation Rudolphine Tables Tycho Brahe Aristotle Ptolemy Deferent and epicycle Physics Isaac Newton Newton's law of universal gravitation Newton's laws of motion Satellite Sun Drag (physics) Relativity Tests of general relativity Charon Earth Mercury (planet) Moon Pluto Center of mass Conic section Eccentricity (mathematics) Polar coordinate system Copernican principle Orbital eccentricity Comet Dwarf planet Hyperbolic trajectory Parabolic trajectory Point (geometry) Triangle Angular momentum Astronomical unit