Globular Cluster M15
Like most globular clusters, M15 lies outside the plane of our galaxy, but is part of it – likely a remnant of the Milky Way’s original formation; a cluster of stars that just never got mixed in with the rest of the galaxy. M15 is one of the oldest, somewhere around 13 billion years old.
It’s about 35,700 light-years from Earth, and contains over 100,000 stars! It has some unique features – the first planetary nebula within a globular cluster was discovered in M15, it has lots of variable stars and pulsars within it, and it’s also one of the densest globular clusters we have. Its core collapsed at some point in its history, which astronomers believe may have led to a black hole at its heart.
What steals the show in this image is the “galactic cirrus” surrounding it – faint clouds of gas and dust lit up by the collective light of our galaxy as a whole. And since we are looking in a direction outside the plane of our galaxy, you’ll spot lots of incredibly distant background galaxies as well.
A total of 26 hours of exposure time on this image, over the span of 19 nights.
