In Search of Darkness

IC 342Star light, star bright, first star I see tonight…First star? Hello? You’re supposed to come out now. Stars? Someone? Shine? Please?

While I was a graduate student at the University of Texas in Austin I watched the Ring Nebula (M57) disappear. When I first arrived in 1996, this former stellar atmosphere was clearly visible in binoculars from the roof of the building I worked in (RLM). In 2000 I could no longer see it, but some of my more owl-eyed students could see it faintly contrasting against the background glow of too many city lights. When I graduated in 2002, it was just gone. No pair of 10×50 binoculars was going to find it. According to the Greater Austin Chamber of Commerce the city grew from 846,227 people in 1990 to 1,452,529 people in 2005. With that growth came lights, and with those lights came star consuming light pollution. As the world population grows and becomes progressively more industrialized, our entire planet is losing its ability to see faint stars and galaxies in the night skies.

In an attempt to raise awareness about this problem and document what is going on, the excellent education team at the GLOBE is getting ready to run their the GLOBE at Night program. Last year, over 18,000 people from 96 countries from all continents except Antarctica participated, documenting how light pollution effects the skies everywhere.
I strongly encourage everyone to participate in this project for one simple reason: So you can compare what you see with an image of what you would see if your skies were perfect.

One of my most eye opening experiences as a young astronomy student came while sitting on a rock at the foot of a glacier in the Northern Caucus Mountains. It was the middle of the night. Our camp fire was down to low embers behind me, and looking away from camp the mountains loomed darkly against a star-bright horizon. As I sat facing the ecliptic, I struggled to find the familiar signs of the zodiac among the million points of light. As I searched for familiar patterns I kept getting distracted by satellites. There was simply too much in the sky and I was lost.

I’ve seen dark skies since then. Observing at McDonald Observatory I learned that in dark locations clouds are blobs of blackness – the great nothing of the Neverending Story – against a starry backdrop. I also learned that a few 100 people who don’t turn off their lights can create a yellow patch on another wise blue-black horizon. The major observatories of the world are each trying to save their skies from encroaching city lights. Recently, Kitt Peak Observatory released a spectacular image of a very faint face on spiral galaxy (IC 342, above right, credit: T.A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN, and NOAO/AURA/NSF) to showcase just what their telescopes are capable of thanks to progressive city ordinances curbing light pollution. As the nearby city of Tucson has grown, light pollution at Kitt Peak has grown, but very slowly. Today, it appears that additional growth may be possible without degrading Kitt Peak’s skies.

Not all observatories are lucky enough to have nearby cities and townships work so hard to curb pollution. For instance, consider the misfortunes of California’s Mt Wilson Observatory with the great Palomar telescope. Built on the hills outside Los Angeles, this telescope has watched the city grow and the sky light up with the light from several million people. It doesn’t have to be this way. To protect our skies only 4 simple steps are necessary: Don’t use more light than is necessary for a given task, point lights down from above not up from below, shield light so it doesn’t scatter upward, and use low-pressure sodium lamps as much as possible. These 4 steps will save our skies, and also save on electricity (which saves our entire planet).

With the lose of our skies, we aren’t just losing our ability to see stars, we’re also effecting out health and nature. Hatchling sea turtles aren’t finding the sea. Rodents that eat by the cover of darkness are more easily eaten. Lots of bad stuff that is outlined effectively on The International Dark Sky Association’s (IDA) resources page.

So, go out and lookup with the GLOBE, and then go in and find out how you can help IDA protect what is left of out skies.

One Comment

  1. Jorge Schrauwen March 11, 2007 at 5:33 pm #

    I’ve never seen complete or near complete dark skies yet :(

    But I’ve notice that there is a huge difference between Antwerp (near where I live) and let say 50km from here where there are just small towns.

    I was shocked at how much stars I saw in Italy!

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