This is an illustration of one of the most massive star clusters within our Milky Way Galaxy. The cluster is ablaze with the glow of 14 rare red supergiant stars. Interspersed among the supergiants are young blue stars. The cluster contains an estimated 20,000 stars and is 20 times more massive than typical clusters in our galaxy. The cluster is located in the direction of the Galaxy's center. Its visible light is obscured by interstellar dust, but infrared telescopes easily detect the cluster's glow. If it could be seen in visible light, it would resemble this illustration. In this perspective we are looking back across the Milky Way, in the direction of the Sun, 18,900 light-years away. The cluster is only 8 to 10 million years old, young enough for astronomers to see most of the red supergiants before they explode as supernovae. One supernova remnant is located in the cluster at far left. In the background at the 12:00 position is a distant region of stars called W 42.
Mystery Solved: High-Energy Fireworks Linked to Massive Star Cluster [ http://www.spitzer.caltech.edu/Media/releases/ssc2006-03/release.shtml ]; Hubble Space Telescope Press Release [ http://hubblesite.org/newscenter/newsdesk/archive/releases/2006/03/ ] GLIMPSE Feature Article [ http://www.spitzer.caltech.edu/features/articles/20051220.shtml ] 2MASS [ http://www.ipac.caltech.edu/2mass/ ]