When the sunlight (or moonlight) interacts with the water droplets and ice crystals that make up clouds, optical phenomena can appear in the sky. This section includes a variety of these atmospheric optics, from the common rainbow to the rarer circumhorizontal arcs, glories, and more!
Some useful terms to understand these phenomena are as follows (these definitions are how these words apply to atmospheric optics):
– Refraction: the bending of sunlight upon entering drops or crystals, separating the sunlight into the colors of the visible spectrum (leading to formation of sun halos, sundogs, arcs, etc.)
– Reflection: Light can change direction within drops, at times bouncing the light back to the observer creating more common phenomena such as rainbows. Multiple reflections can also occur.
– Diffraction: When light is bent around a drop or crystal.