Instructions:
Use the slider to change the eccentricity of the Ellipse. Click a button to jump to a preset.
Explanation:
The realization by J. Kepler that the planets orbited the sun in elliptical paths rather than circles was a monumental breakthrough in understanding our solar system. Newton would later show that elliptical motion is a result of the inverse square law of gravity. But, for most of the well known objects in the solar system, the elliptical nature of the orbit is not very extreme. The difference between their paths and a perfect circle is not obvious at first.
Link to stand-alone sim: Here is a link to view the sim on its own, with no distractions.