Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/742224
Bill Langer is a consulting research geologist who spent 41 years with the U.S. Geological Survey before starting his own business. He can be reached at Bill_Langer@hotmail.com CARVED IN STONE 44 AGGREGATES MANAGER / November 2016 I recently saw the most amazing thing; something I wish you all could experience. My wife, grandkids, and I love to camp. One moonless night, we stayed at a campground in the high desert of Arizona. The campground had no outside lighting and forbids guests from turning on their campers' outside lights. The campground was pitch black, and there was a spectacular, starry sky. I hadn't seen a nighttime sky like that since my childhood. I am luck- ier than most. I grew up in a very small town with hardly any streetlights. People left their front lights off except when checking on a daughter as she and her boyfriend were saying goodnight on the porch. My dad, our dog, and I would take nighttime walks on the outskirts of town and regu- larly get to enjoy beautiful starry skies. But I had forgotten how glorious a dark sky really is. The dark sky at the campground allowed us to see bazillions of stars. To the south, we could see the Milky Way. It looked like a moonlit cloud arcing across the sky. Our eyes could not resolve it into individual stars, so we got our binoc- ulars; that small amount of magnification divided the Milky Way into more stars than you can imagine. A hundred years ago, seeing the Milky Way was a part of our ancestors' everyday life experience. But, quite likely, most of you reading this article have never seen it. That is because the majority of man- kind lives in cities, and the city lights overwhelm the Milky Way. Most of you will probably need to make a special effort to see the Milky Way. First, you must find a truly dark location. The accompanying map shows the areas in North America with the brightest and darkest sky. (A larger version of the whole world can be found at: http://advances.sciencemag.org/content/2/6/e1600377. full.) If you live in a city, you can probably identify it as one of the red or yellow splotches. Identify a green, blue, or black location near you; that's your viewing location. It will probably require a drive of an hour or more to reach a dark enough location where it will be visible, but it is well worth the time and effort. If you go, choose a moonless, cloudless night. Take someone with you to share the experience. And don't forget your bin- oculars. Block any nearby lights from your view and wait about 20 minutes for your eyes to adapt to the dark. If you live in the Northern Hemisphere, the center of the Milky Way will be low in the southern sky, and the band of the Milky Way will sweep upwards in an arch across the eastern sky to the northern horizon. Look for a milky cloud. Some parts will be brighter than others, giving a faintly mottled effect. You may also see some "holes" in the Milky Way: clouds of interstellar dust blocking our view of the stars beyond. I sincerely hope you take the opportunity to enjoy the sheer beauty of a dark nighttime sky and the Milky Way. It is truly a galactic wonder. While geologic wonders have been in focus, this galactic wonder deserves recognition as well. The Milky Way Photo courtesy Bureau of Land Management The new world atlas of artificial night sky brightness, F. Falchi, 2016.