Galaxy Classification. jifukrey@gmail.com Galaxy A galaxy is a massive, gravitationally bound system consisting of stars, stellar remnants, gas, dust, and dark matter. Galaxies range in size from small dwarf galaxies with just a few billion stars to massive elliptical galaxies that contain trillions of stars. The Milky Way is the galaxy in which our solar system resides. It is a barred spiral galaxy with a central bar-shaped structure surrounded by four major arms and several smaller arms tha...