This image is not in true color. Hydrogen is mapped to green, Oxygen to blue, and Sulfur to red. The predominantly cyan color of the image is due the co-location of Hydrogen and Oxygen, which of course are the two components of water. While water is probably not yet abundant in this nebula, it’s clear where it all comes from.
The entire image is about 110 light years in width, a staggering size when you think about it. Light that left a star on the left edge of the image on the day I was born has only made it halfway across the image at this point.
This nebula is somewhere around 5000 light years distant. The light my camera recorded left that object some 500 years before Egypt’s pyramids were built. Virtually all of recorded human history occurred in the time it took that light to arrive at my camera in the winter of 2013. Virtually all of the technology used to capture, process, display, and distribute the image on flickr was invented in the last .6% of its journey.
While it may appear that there are a large number of stars in this nebula, remember that we’re looking through 5000 light years of space to see it. Most of the stars recorded in the image are somewhere between here and there. That said, there are indeed a large number of stars in this nebula, but most of them are visible only in infrared light because they’re still embedded in their cocoons of gas and dust deep inside. Eventually the radiant energy from these newborn stars will dispel the entire nebula, leaving only a sparkling cluster of stars with their solar systems and all the ingredients of life itself.
I’ve reduced the size of this image by 50% from its full resolution of 3720x3444. At that resolution, each pixel spans about .03 light years, so in this version’s full resolution, each pixel spans .06 light years. While that might seem small, Pluto’s orbital diameter is about .0013 light years, so 46 of our solar systems would fit within each pixel.
You can find more technical information on this image’s Astrobin page.