In every society there are those who do not play by the rules, and who dream of taking long journeys of pilgrimage. In our Solar System, these maverick renegades are also the most mysterious; they are the comets that bring magic and wonder to our night skies. Unexpectedly, and beyond our wildest imaginings, they are the source of all true magic- they hold the key to the origins of life on Earth.
All objects in our Solar System planets travel on predictable, elliptical paths around the Sun. Newton's physical mathematics have enabled us to chart out the movements of the planets, moons and asteroids, but the comets surprise us from afar. Swooping in to visible range from the outer limits of observational distance, they travel along the most extreme of orbital paths.
Zooming past the Sun and then back out into the edge of the Solar System, their "year", or orbital period, can last for millions of years. With high-precision observations, comets are indeed mathematically predictable. However, sometimes comets break up, collide with other objects or are gravitationally deflected out into the cold distances between the stars. Humans have so far observed and catalogued more than five thousand comets- a small number when compared to the trillions of them theorised to be orbiting the Sun.