a very large spiral galaxy with many stars

Triangulum Galaxy (M33) Crop Caption: Hubble Maps an Undisturbed Spiral Galaxy in the Milky Way's Backyard. NASA's Hubble Space Telescope has produced its largest mosaic image ever of the Triangulum galaxy (M33). This image spans 14,500 light-years. Credits: NASA, ESA, and M. Durbin, J. Dalcanton, and B.F. Williams (University of Washington)