Rosette Star-birth Nebula
Not everything in astronomy was named poorly. The only things this cosmic rose is missing is a stem, thorns, and leaves… But the color is good, right? However, if this nebula was gold in color as some astrophotographers color it, maybe we would have called it the “Glazed old-fashioned cake donut nebula”? And yes, roses come in yellow, but we don’t want you to be “in like” with astronomy. We want you to love astronomy!
Most nebulae are mostly brown, blue, or red. Research astronomers use filters to block those predominant colors and, if necessary, manipulate software saturation sliders to draw out the tiny amounts of yellow and green. The resulting rainbow of colors helps reveal details like the Bok Globules, which are the extra dense lumps of dust and gas from which newborn stars hatch. Of course, they are also visible in this authentically red image, you just have to study the photo a little more closely. Many astrophotographers, mimic this practice. Some might be hoping it lends scientific credibility to their work. Others probably just like making space as pretty as possible.
The Rosette Nebula is truly red, and yet at 5,000 light years away, the rate of photons that manage to land inside even a BIG telescope is so low that the red can only be accumulated enough to be revealed in long-exposure photography. Complicating matters, red is the hardest color for human eyes to detect, especially while in night-vision mode. Therefore, even when looking at this nebula through our biggest telescopes, it’s difficult to notice the contrast of dark gray against darker gray. Nobody would buy a framed print of a gray rose, so we present the authentic photography version rather than approximating the authentic human view.
If you think that’s pedantic, we are only getting started. Paradoxically, nebulae are only colorful from very far away. In fact, if you were inside a nebula, you would only see empty space. Even long exposure pictures would reveal nothing besides distant stars. Yet, stars in that night sky would be sharper and brighter than our view of space which is partially obscured by Earth’s super-dense nebula known as “our atmosphere”. In extreme contrast, space nebulae are as close to being nothing as anything in the Universe can be, and still be referred to as something. Where Earth’s invisible air has 10 quintillion (19 zeros) molecules per cubic centimeter, star-birth nebulae average below 10,000/cm3 which is the ultimate kind of transparent.
First consider the age-old question, ‘Why is the sky blue?’ The answer is that nitrogen, oxygen, carbon dioxide and water-vapor (99.9% of our planets atmosphere) all have small enough kinetic diameters, that these molecules can normally only “scatter” (aka reflect in different directions) blue light. In particular water molecules, because they have the smallest sphere of influence in disrupting inbound photons from our Sun, are only barely blue. This is why small amounts of water, like a glassful’s worth are transparent, but huge amounts of H2O in the form of streams, lakes, and oceans are blue, if you are looking at them from a distance. Yes, reflection from a blue sky helps “blue” bodies of water, but they don’t turn white under cloudy sky, do they? Finally, swimmers among us will have noticed that when you are inside a body of water it’s back to being mostly transparent again? Yet when you hop out into the boat or on to the dock, that same water is mostly blue again. Magic? No. Science! When the scattered light come from a single direction, up in case of a lake, or down in the case of the sky, you can detect the accumulation of faint amount of color. But when the light is scatter from every direction, below the surface, or inside a room, there less color. So too are nebulae invisible from the inside, and only translucently red, blue, or brown when viewed from light years away where all photons are coming from the same tiny point in the sky.
Once you grasp this reality, Science Fiction will be further ruined for you. Star Trek spaceships flying through colorful nebulae is even more cartoonish than Crayola®-ing your astrophotography. Much to the Dark Rangers’ disappointment, even NASA and the European Space Agency (ESA) seem to prioritize pretty over plausibility and consequently have filled their YouTube channels with many such misleading nebula fly-through animations. It would be excusable if these high-production-value animations came with a footnote explaining the true nature of these space clouds. That would leave a jumping-off point for curiosity and deeper understanding. Without that it more like science fiction than space science.
Who are the Dark Rangers to fault the two of our planet’s four leading space agencies? Science doesn’t really care how popular or well-funded you are, it only cares about whether your presentation of information is consistent with reality or not. It doesn’t even matter that at the time of this printing, Dark Ranger Telescope Tours remains the #1 ranked telescope experience on Earth – according to TripAdvisor.com That’s not necessarily an indication of scholarship, just a measure of how entertaining we are. But it does suggest that the difference might be that we don’t feel we have to compromise scientific accuracy to wow people.