Comets are made of ice, dust and gas. Image Credit: NASA
Asked by Ben Davies
Comets follow elongated – or elliptical – paths around the Sun. In comparison, planets follow almost circular orbits around our star. When a comet reaches the point in its orbit called perihelion, it swings closer to the Sun and also appears to travel faster. Its most distant point from our star marks its aphelion.
The time it takes for a comet to complete one circuit of its orbit is called its orbital period. It is from this that these dirty bodies of ice and dust can be classified. Comets who take less than 200 years to finish one lap around the Sun are known as short- period comets. An example is Halley’s comet, which takes 76 years. On the other hand, there’s the long-period comets, such as Comet Hale-Bopp, which completes its orbit once every 2,500 years.
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