Astronomy Answers: From the Astronomical Dictionary
The description of the word you requested from the astronomical dictionary is given
Johannes Kepler (1571 - 1630) defined the three Laws of Kepler that
properly explained the motion of the planets around the Sun for the
first time. The three Laws of Kepler are:
- Each planet moves around the Sun in an orbit that is an ellipse,
with the Sun in one of the foci of the ellipse.
- The straight line segment from the Sun to the planet covers the
same amounts of area of the ellipse in the same amounts of time.
- The third power of the semimajor axis of the orbit of a planet is
proportional to the second power of the orbital period of the planet
around the Sun.