By Martin MacPhee
The Eagle Nebula, also known as Messier 16 or M16, consists of a star cluster and many emission nebulae and dark nebulae, in the direction of the constellation Serpens. It’s the location of several famous structures including the Pillars of Creation, whose photo you see in this post. Take a look at the photos here, and delve deeper into this region of space, which is one of the most interesting and beautiful we know.
In the late 18th century, when this object began to be catalogued by astronomers, only the star cluster could be seen, and this was designated as M16 in Messier’s catalog of things not to be confused with comets. Later, this star cluster became known as the Snow Queen Cluster.
The advent of astrophotography revealed a large area of glowing hydrogen gas that was invisible to the unaided eye, and that looked somewhat like an eagle with outstretched wings, giving rise to the current common name of Eagle Nebula.
As higher resolution photography and then digital photography began to reveal more and more features, particularly the dark patches (aka dark nebulae), many distinct features within the Eagle Nebula were given individual names. Today, the informal name of the Eagle Nebula is taken as referring to all of these in one collective designation. Some of them are famous, and all are beautiful.
The Eagle Nebula suddenly burst upon the world’s collective consciousness in 1995, when the Hubble Space Telescope focused its attention on a dark nebula in the center of the Eagle, which you can see in the photos above and below.
The dark protrusions of dense gas were found to be the site of new star and solar system formation, and the resulting photograph became known as the Pillars of Creation and gave most people their first view of new stars and solar systems at the dawn of their creation.
Similar areas, such as the Stellar Spire on the left side of the Eagle, are also forming new stars, through a combination of processes. The cold, mostly hydrogen, gas of the nebula has already fueled the formation of a series of young, hot stars. As the gas continues to collapse under its own gravity into the dark forms we see, new stars and solar systems are formed and continue to grow as they attract more and more gas to them. However, the intense light pressure from the new stars that have formed and their solar winds are eroding away the dense, cold gas pockets, diminishing new star formation and dispersing the nebulae.
At the same time however, the shock waves where the light and solar wind impacts the cold gas, heat and compress some of the cold gasses at the same time, resulting in a new set of star forming environments
I am very pleased I can see these structures in my ‘scope, which is only 8″ in diameter, especially given that they are located around 7,000 light-years away, and the Stellar Spire is roughly 9.5 light-years (~ 9 trillion kilometers) tall – about twice the diameter of our solar system. In seeing them from my driveway in the heavily light-polluted Maryland suburbs of Washington D.C., I’m doing very well. And for approximately $10,000,000,000 less than the Hubble telescope cost, which makes my wife very happy too!
Enjoy the view while you can. Sadly, data from other telescopes has shown that the Pillars and Spire are likely already gone, victims of a massive shock wave from a supernova explosion that happened 8,000 to 9,000 years ago. Its light has already gone past us, but the slower-moving shock waves would have taken thousands of years more to sweep through the Eagle Nebula, destroying the delicate structures we find so entrancing.
The light of that destruction is already on its way to us, so in a few thousand years, people will be seeing a very different Eagle in the ever-changing sky.
Bottom line: What we know today as the Eagle Nebula, or M16, once was thought to be a simple star cluster. Astrophotography revealed the structure that resembled an eagle and gave the Nebula its current name. The Hubble Space Telescope revealed even more detail, so that today the Eagle Nebula is known as home to at least two famous structures: the Stellar Spire and the Pillars of Creation.