Kepler’s Three Laws of Planetary Motion

The laws were formulated between 1609 to 16l9, and are (as usually stated):

    <ul>   <li> Planets move around the Sun in <strong>ellipses</strong>, with the Sun at one focus    </li>   <li> The line connecting the Sun to a planet sweeps <strong>equal areas in equal times. </strong></li>   <li> The<strong> square</strong> of the orbital period of a planet is proportional to the                                                              <strong> cube</strong> (3rd power) of the mean distance from the Sun in     (or in other words--of the&quot;semi-major axis&quot; of the ellipse, half the sum of smallest      and greatest distance from the Sun)      </li> </ul>   <ol>  </ol> <!--more--> <a href="http://www-spof.gsfc.nasa.gov/stargaze/Kep3laws.htm" target="_blank" rel="noopener noreferrer">Read more . . .</a><br />