This July 4, many people will be outside, looking up at the night sky.
On July 5, when you look up at the night sky, what will you see? Most of us would say stars. Some might say the Milky Way.
Truth be told, if you look up at the night sky anywhere in our diocese — or most of the continental U.S. — you will most likely see “sky glow.”
Sky glow is a phenomenon that has steadily increased in the last 50 years. It is the result of light pollution, defined by the National Optical Astronomy Observatory as “excessive, misdirected, or obtrusive artificial (usually outdoor) light.” The observatory adds that light pollution “washes out starlight in the night sky, interferes with astronomical research, disrupts ecosystems, has adverse health effects and wastes energy.”
Sky glow happens when lights from cities travel upward into the sky, creating an orangey haze. Sky glow is so bad that, for many places in the U.S., most of the Milky Way is obscured.
I discovered this myself last year, when I spent a couple of nights in northern Oconto County. This is one of the few areas in our diocese that earns a nearly dark rating on sky glow maps (See dark sitefinder.com/maps/world.html). Though I hadn’t realized it until then, this was the first time in years that I had truly seen the Milky Way. Its huge spangle of stars, streamers of light and swirling glows of star stuff dazzled my eyes. I looked up and felt as if I were falling up into the sky.
Earlier this year, John Barentine, program manager at the Tucson, Arizona-based International Dark-Sky Association, spoke at the Faith and Astronomy Workshop in Tucson, sponsored by the Vatican Observatory. Barentine addressed how the natural night sky is under threat from the growing desire to light up the night in our cities. His talk was cited in the Catholic News Service blog (cns blog.wordpress.com). Barentine noted that, if the current trend continues, by 2025, half of all U.S. residents will experience perpetual twilight.
Sky glow interferes with birds’ migration and navigation, causing them to fly at night and to crash into tall buildings. Newly-hatched sea turtles are increasingly disoriented at night and unable to reach the ocean before predators eat them. Light pollution affects plant flowering and tree growth, and disrupts circadian rhythm in human beings. A study by the American Geophysical Union found that light pollution even worsens smog in big cities.
We need to assure that our children are able to see the night sky lit up with stars instead of by an orange glow. But how? I’ll admit it: I contribute to sky glow. I have outdoor lighting. I prefer my streets and parking lots lighted. And I like the cost-saving features of LED lighting. But I now realize that each of these adds to light pollution.
However, I don’t need to give all these up to reduce sky glow. Instead, I can switch to motion-sensing lights outdoors. I can use warm-white LED bulbs instead of the much harsher blue-white LED bulbs. I can shield the lights I do have outdoors, so that their beams are directed downward toward the ground and my eye-level — which is where I need them — and not upwards into the night sky — where I don’t need them. I can ask the same of my city, of the streetlights outside my home and for the parking lot where I work.
I’m a huge fireworks fan, but the stars are a lot better. Whatever we can do to let future generations — and ourselves this summer — see that Milky Way can really light up the sky, for all of us.