A cloud of interstellar gas or dust that becomes visible by the reflection of light from nearby stars.
Messier 78, northeastward of Orion's Belt, is an example of a reflection nebula. A binary pair of bluestars, HD 38563, shine their light across a patch of the Orion Molecular Cloud, creating a bright zone that is partially obscured by an arcing tendril of dark material. Imagery provided by Aladin sky atlas
