The Andromeda Galaxy is named for its location within the Andromeda Constellation. The galaxy was known to Persian astronomers as early as 905 AD. It is one of our closest neighbors, at 2.5 million light years from Earth. The Andromeda Galaxy is estimated to have 1 trillion stars all rotating together. It’s a spiral galaxy with a central bulge of stars and arms of stars, dust and gases. There are more than 30 satellite galaxies that cluster around the much larger Andromeda Galaxy. Galaxy M 32 can be seen in the lower left of the photograph, while M 110 is just above and to the right of the center of the Andromeda Galaxy.