Kepler’s Laws of Gravitation – Law 1
Johannes Kepler’s helped shape our understanding of gravity. While the basic principles of gravity seem intuitive to us now in the 21st century, the reason for gravity and its workings were not understood in the 16th and 17th century.
How do planets move? Do planets travel in circles?
Kepler was able to determine how planets should move along a path. While we have a strong grasp of circles and appreciate the ease at which circular mathematics provides us, we simply can not count on all science to be easy.
What Kepler found was that planets do not travel around stars in circular orbits – rather they move around their parent stars in ellipses.
While we will investigate this further, it may be prudent to refresh yourself with the mathematics of ellipses. NASA has provided a tutorial on elliptical orbits which you may find useful – http://istp.gsfc.nasa.gov/stargaze/Skepl1st.htm.
Math of an Ellipse
Once you have mastered ellipses, you are ready to move on to Kepler’s next two laws of planetary motion.
