What is the difference between these small comets and the large comets like Hale-Bopp and Halleys?
The small comets are a million times smaller than these more famous comets. The small comets also contain little dust and lack the iron and other metals necessary to make them glow brightly and produce a tail like the larger comets. But what they have in common–and the reason they were dubbed “small comets” in the first place–is that they are both largely made of water.
