Non-Circular Orbits (OCR GCSE Physics A (Gateway Science Suite)): Revision Notes

Comets have non-circular orbits that are highly elliptical (stretched out) or hyperbolic, unlike the nearly circular orbits of planets. Due to their elongated paths, a comet's speed varies significantly depending on its distance from the Sun.

Key characteristics of cometary orbits include:

• Highly elliptical orbits: These stretched paths cause comets to speed up as they approach the Sun and slow down as they move away.
• Changing speed: As a comet approaches the Sun, it loses gravitational potential energy and gains kinetic energy, increasing its speed. This creates a slingshot effect, propelling the comet back into space after it passes the Sun.

• Different orbital planes: Unlike planets, not all comets orbit in the same plane or direction.

As the comet moves away from the Sun, it slows down, eventually completing its orbit and beginning its journey back towards the Sun, maintaining a stable, repeating orbital path.