The European Southern Observatory (ESO) Has Released A Beautiful New Image Of The Open Star Cluster Messier

The European Southern Observatory (ESO) has released a beautiful new image of the open star cluster Messier 7.  This new view of a middle-aged star cluster (also known as “M7”) comes in the form of an ESO photo release.  Using the MPG/ESO 2.2-metre telescope at La Silla Observatory in Chile, the image was taken with the Wide-Field Imager and shows a window of sky about 1° across, or twice as wide as a full Moon. The cluster stars are the big, (mostly) blue ones in the foreground, about 1000 light years away; the thousands of other, fainter stars are many times more distant as the line of sight in this view is one of the most dense through our Galaxy’s disk.  

At 200 million years old, Messier 7 is a snapshot in the middle of the evolution of a typical star cluster: the gas and dust from which the stars formed are long gone, but the resulting stars are still near each other in space.  The blue stars are evolving rapidly and will be the first to disappear, while the longer-lived cluster stars will slowly drift apart over the next billion years or so.  According to the photo release, “As they age, the brightest stars in the picture — a population of up to a tenth of the total stars in the cluster — will violently explode as supernovae. Looking further into the future, the remaining faint stars, which are much more numerous, will slowly drift apart until they become no longer recognisable as a cluster.”