قانونهای ِ کپلر
qânunhâ-ye Kepler (#)
Fr.: lois de Kepler
1) The planets move about the Sun in ellipses, at one focus of which the Sun is situated.
2) The → radius vector joining each planet with
the Sun describes equal areas in equal times.
3) The ratio of the square of the planet's period of revolution to the cube of the
planet's mean distance from the Sun is the same for all planets.
→ Kepler; → law.