Astronomy & Astrophysics 101: Structure of a Comet

Comets are icy bodies that formed alongside the planets in the early Solar System before being flung into its distant outer regions. When they return to the inner Solar System, the Sun’s heat and radiation activate them, causing them to release gases and dust. This material forms a glowing cloud around the comet’s solid nucleus, [...]

from SciTechDaily https://ift.tt/JTcVBRN