Transcript: Galaxy colors are indicative of their stellar populations, that is the distribution of colors of the stars in the galaxy based on their masses and luminosities. The stellar populations of elliptical galaxies are generally old, and so elliptical galaxies appear red. The bulges of spiral galaxies are also older stellar populations and appear red. But in the spiral arms many young stars are found, and so spiral galaxies in their spiral disks are blue or white in the color of their stars. Irregular galaxies mostly contain young, blue and white stars, although with very deep imaging it is possible in some cases to see an older, redder stellar population.