categories: periodiccomets (e.g. Halley's Comet), non-periodiccomets (e.g. Comet Hale–Bopp), comets with no meaningful orbit (the Great Cometof 1106), and
short-period comets. Similarly, although the literal meaning of "non-periodiccomet" is the same as "single-apparition comet", some use it to mean all comets that
result many comets have more than one name. The simplest system names comets after the year in which they were observed (e.g. the Great Cometof 1680). Later