Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies [ http://crux.astr.ua.edu/gifimages/coma.html ] pictured above [ http://www.mistisoftware.com/astronomy/Galaxies_ComaCluster.htm ] is one of the densest clusters [ http://www.astr.ua.edu/white/mug/cluster/clusters.html ] known - it contains thousands of galaxies [ http://www.seds.org/messier/galaxy.html ]. Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy [ http://www.damtp.cam.ac.uk/user/gr/public/gal_milky.html ] does. Although nearby when compared to most other clusters [ http://antwrp.gsfc.nasa.gov/apod/clusters_of_galaxies.html ], light from the Coma Cluster [ http://astrosun.tn.cornell.edu/courses/astro201/coma.htm ] still takes hundreds of millions of years to reach us. In fact, the Coma Cluster [ http://chandra.harvard.edu/xray_sources/coma/ ] is so big it takes light millions of years just to go from one side to the other! Most galaxies in Coma [ http://imagine.gsfc.nasa.gov/docs/features/objects/coma.html ] and other clusters are ellipticals [ http://antwrp.gsfc.nasa.gov/apod/elliptical_galaxies.html ], while most galaxies [ http://en.wikipedia.org/wiki/Coma_galaxy_cluster ] outside of clusters are spirals [ http://antwrp.gsfc.nasa.gov/apod/spiral_galaxies.html ]. The nature of Coma's X-ray emission [ http://www.lsw.uni-heidelberg.de/users/mcamenzi/Coma_X.html ] is still being investigated [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000A%26A...357...66D ].