Andromeda is the nearest spiral galaxy to the Milky Way, around 2.5 million light-years away. Once thought to be a twin of our galaxy, its different structure is very evident in infrared light. While it is a spiral galaxy, its dust falls largely in a huge ring structure, possibly caused by gravitational interactions with its smaller satellite galaxies.
Optical: This is the classic visible view of the Andromeda Galaxy Infrared: Andromeda's dust ring stands out in the infrared