Non-Circular Orbits (AQA GCSE Physics)

Orbit of a Comet

• The orbits of comets are very different to those of planets:
  • The orbits are highly elliptical (very stretched circles) or hyperbolic
  • This causes the speed of the comets to change significantly as its distance from the Sun changes
  • Not all comets orbit in the same plane as the planets and some don’t even orbit in the same direction

Orbital path of a comet

• As the comet approaches the Sun, it loses gravitational potential energy and gains kinetic energy
• This causes the comet to speed up
• This increase in speed causes a slingshot effect, and the body will be flung back out into space again, having passed around the Sun
• As it moves away from the Sun the body will slow down, eventually finishing its orbit and falling back into towards the Sun once more
• In this way, a stable orbit is formed