A small segment of the "Big Picture". The so-called "Markarian Chain" of galaxies, dominated by the giant elliptical galaxies M84 and M86 on the right, and the merging pair of galaxies NGC 4435 an NGC 4438 near the center (galaxy collisions and mergers are relatively common in environments such as the Virgo cluster, and were much more frequent in the past). The differences in the colors of galaxies are largely due to the differences in their star formation: bluer galaxies are actively making stars now, while redder galaxies are just aging passively; presence of interstellar dust also makes galaxies look redder.

Image credit: The Palomar-Quest Team, California Institute of Technology