Kepler's laws
–noun Astronomy. | three laws governing planetary motion: each planet revolves in an ellipse, with the sun at one focus; the line connecting a planet to the sun sweeps out equal areas in equal periods of time (law of areas); the square of the period of revolution of each planet is proportional to the cube of the semimajor axis of the planet's orbit (harmonic law). |
| law of areas |
noun |
| a law concerning the speed at which planets travel; a line connecting a planet to the sun will sweep out equal areas in equal times; "Kepler's second law means that a planet's orbital speed changes with its distance from the sun" [syn: Kepler's second law] |
