One of the first things that grabs your attention when stepping outside after sunset on a late summer evening is the sweeping expanse of the Milky Way. It stretches from one horizon to the other. In the center of that vast ribbon of starlight, there’s a familiar arrangement of stars called the Northern Cross. In the heart of that cross, perfectly aligned with the main beam, there is a nebula called the Crescent Nebula. In the center of that remarkable cocoon of gases lies the energy source, a Wolf-Rayet star named WR 136. Wolf-Rayet stars are massive stars that are extraordinarily powerful. They are often highly unstable too, sometimes blowing up spectacularly in what’s called a supernova explosion.
WR 136 in the center of the Crescent Nebula has such an intensely powerful production of energy that the outer layers of the star are getting caught up in the energy outflow. This forms what’s called a stellar wind. The wind carries mass away from the star at the rate equivalent to one Earth mass every eleven days.
In this photo, you can see the process in action as a huge cloud of gases is expanding outward from WR 136. The Crescent Nebula looks similar to a crescent roll. Whereas a crescent roll has great taste, the Crescent Nebula has great waste. The size of the cloud is believed to be about 25 light years in diameter, which means it is nearly 150 trillion miles across. It’s believed to be about 5,000 light years away, but if it were as close to us as the nearest star, it would cover most of the night sky.
The two colors visible in the cosmic bubble show the primary elements found in the cloud. Hydrogen shows up as red, and oxygen shows up as blue. The background of the photo shows lots of red hydrogen gas meandering through the rich Milky Way starfield.
The nebula is faintly visible in a medium or larger-sized backyard telescope. It shows up as a gray wispy arc. The color is hard to see because of the dim light levels and the fact that our eyes aren’t very sensitive to extreme red light produced by hydrogen emissions.
Much more detail can be seen in the Crescent Nebula with astrophotography. This photo is the result of six hours and eight minutes of exposure time from a ten-inch reflecting telescope. A total of ninety-two four-minute exposures were stacked together to bring out the faint details in the nebula.
The great waste of the star WR 136 forming the Crescent Nebula is but a small thing to its Creator and not actually a waste after all. It simply shows the great taste its Maker has in perfecting beauty in His universe.