Section 5.4.2: What shapes are orbits?
In the 17th century, Johannes Kepler famously published his three laws of planetary motion. Isaac Newton subsequently showed that Kepler's laws are a natural consequence of his universal law of gravitation, and apply to all bodies moving under the influence of gravity.
ACTIVITY: The following NASA video explains Newton's derivations in more detail.orbits-keplerVideo player: orbits-kepler.mp4
It's not just the planets in the Solar System that follow orbits obeying Kepler's laws. All satellites and space probes also obey the same rules.
ACTIVITY: In the following video, Professor John Zarnecki explains how orbital dynamics are important when trying to chase a comet.giotto.mp4Video player: giotto.mp4