Are Comets Wanderers from Another Star System?
Comets, long-lost members of the solar system’s fragmentary birth, have always been a mystery. In the Middle Ages they were seen as portents of disaster, invoking dire warnings of fire, flood, disease and pestilence. Some religious groups even believed they were the dearly departed souls of their loved ones making their way to Heaven. These days we know them more as a fascination to look up at in the night sky, to photograph and marvel at. But, where did they come from? That’s a good question, and the answer may not be from where you think. Along with asteroids they make up the flotsam and jetsam of our solar system. Astronomers believe that they originated great distances away, travelling to the inner solar system from that frozen region outside Pluto called the Oort cloud, halfway to the nearest star. They are the icy counterparts of asteroids impregnated with life-giving water-ice, and perhaps the building blocks of life. New computer simulations show that many comets – including so
