The team discovered that the weak optical signal was in fact embedded in a much larger and rapidly rotating disk of hydrogen gas, characteristic of a robust spiral galaxy. The newly discovered galaxy is the first large nearby galaxy discovered in the constellation Cepheus and was therefore designated Cepheus 1. It resides in a neglected patch of sky called the Local Void. There is only one other sizeable galaxy in this Void, and the emptiness of the region may well be a clue to the nature of Cepheus 1. LSB galaxies contain copious amounts of gas, but, unlike the situation common in most gas-rich galaxies, the gas is evolving to stars only very slowly.
Most galaxies occur in large clusters or groups, and interact with each other gravitationally.
The largest galaxies probably evolve by cannibalizing smaller ones. The Milky Way and its nearest large neighbor, the Andromeda galaxy, are on a collision course and will merge dramatically in a few billion years. Unrecognized earlier because of the primitive state of its stellar constituent, Cepheus 1 nevertheless is so nearby that it appears almost as large as the full moon, and is thus one of the ten largest spiral galaxies on the sky. The significance of its discovery is several fold. Cepheus 1 will serve as one of the nearest large examples of the class of LSB objects, making it amenable to detailed investigation.