In order to understand the orbits of planets, comets, and other celestial bodies, it is necessary to examine the principles of how gravity and the velocity of an object interact to produce an orbit. 

It is a common misconception among students that planetary orbits are circular.

  • Marble-ous ellipses - classroom demonstration video, VP02
  • Released 30/07/2014
  • Length 00:04:06
  • Language English
  • Footage Type Documentary
  • Copyright ESA