The large disk-shaped aggregation of stars, gas, and dust in which the solar system is located. The term Milky Way is used to refer to the diffuse band of light visible in the night sky emanating from the Milky Way Galaxy. Although the two terms are frequently used interchangeably, Milky Way Galaxy, or simply the Galaxy, refers to the physical object rather than its appearance in the night sky, while Milky Way is used to refer to either.