This was
your sky.

A Halo for Andromeda

M31, the Andromeda Galaxy, is the closest large spiral galaxy to our Milky Way, about 2.5 million light-years distant. It shines in Earth's night sky as a small, faint, elongated cloud, just visible to the unaided eye. Invisible to the eye is its enormous halo of hot ionized gas, represented here in purplish hues. This halo was mapped by Hubble Space Telescope observations of ultraviolet light absorption against distant quasars.