Part 10/12:
A common misconception is that every comet always sports a tail. In fact, comets develop tails only when they approach the Sun closely. When near the Sun, the heat causes sublimation of their icy nuclei, forming a glowing coma and sometimes one or more tails that always point away from the Sun due to solar wind and radiation pressure. When far from the Sun, comets appear as small, fuzzy bodies without tails or a coma.