Messier 17 (M17)—otherwise known as the Lobster Nebula, the Swan Nebula, the Horseshoe Nebula, the Checkmark Nebula, and (most commonly) the Omega Nebula—may go by many names, but its beauty is universal no matter what you choose to call it.
Found around 5,500 light-years from Earth toward the Sagitarrius constellation, Messier 17 is impressively large—spanning around 15 light years across. Within it, over 800 stars have taken shape, with more flickering to life all the time. In fact, astronomers estimate that the nebula harbors more material than 30,000 Suns combined (or around 30,000 solar masses).
This new image, which was taken by the ESO’s Wide Field Imager (a tool on the 2.2-Meter Telescope at La Silla Observatory), is color-coded, you might say. Pinkish-red colors correspond to ionization (or HII regions), the big blue-tinged sections are places where dust is so prevalent, light from embedded stars can’t break through with ease. So it bounces back and forth, scattering more effectively at the blue end of the electromagnetic spectrum. Black can be attributed to dark nebulae. Finally, white colors are the result of interactions between hot gas and starlight.
The blue pinpoints of light signify the presence of high-mass stars. (See a larger image here)