Every year, the International Dark Sky Association promotes “International Dark Sky Week” during the week of the new moon in April. The purpose of Dark Sky Week is to bring awareness to the harms of light pollution on our environment, while also promoting the study of astronomy.
Artificial Light and Nature
Humans are wired to be awake during light hours and sleep when it’s dark. The more artificial light around us at night — indoor lighting, outdoor lighting, and light from screens of electronic devices — the harder time our body has following a natural rhythm. A study by Harvard University researchers showed that exposure to blue light, such as the light emitted by smartphones and tablets, suppresses melatonin levels, which makes it hard for us to sleep. Sleep is the time our body takes to recharge and do bodily upkeep like repair muscles and balance hormones and emotions. According to the International Dark Sky Association, there’s also reason to believe exposure to artificial light at night “can negatively affect human health, increasing risks for obesity, depression, sleep disorders, diabetes, breast cancer and more.”
Artificial light not only changes human health, it disrupts the natural world around us. Nocturnal animals such as bats, owls, skunks, and mountain lions are more susceptible to light pollution than animals that are active during the day. Migratory birds use the stars and moon to navigate at night; when the sky is obscured by artificial light, they can fly off course or even into buildings and towers. Similarly, small rodents rely on the cover of night to forage for food. If they stay hidden because of high light levels, larger predatory animals like owls lose access to their food source.
How to Reduce Light Pollution
The effects of light on both humans and animals can be far-reaching and destructive. We rely on lighting to operate safely at night, so it isn’t practical to eliminate it entirely. Luckily, there are ways to both preserve the night sky and continue to use outdoor lighting. The International Dark Sky Association recommends families start out with these five questions to analyze where your family can be more responsible with outdoor lighting around your home.
Appreciate the Sky
International Dark Sky Week is also a time to appreciate the beauty of the night sky, which is why it’s planned around the week of the new moon. With a new moon there is less ambient light, which allows stars and planets to be more visible. A pristine night sky allows us to go stargazing, which is a great way to get out and enjoy nature together as a family.
In South Dakota, we have a deeper connection to the heavens due to both our wide open spaces, and the unique role the stars play in Lakota culture and teachings. In honor of this heritage, Diane Knutson, founder of the South Dakota chapter of the International Dark Sky Association, is hoping to have the Lakota constellation Tayamni recognized as our official state constellation. If the state legislature passes her proposal into law, South Dakota would become one of only three states in the nation to designate an official state astronomical symbol.
While International Dark Sky Week is just one week out of the year, we can use the principles behind it all year. By reducing the outdoor lighting we use regularly, we can protect not only our night sky, but the natural world all around us. Our region is home to many plants and animals that rely on instinctive cues to survive; it’s up to us to help preserve their natural habitat so the Black Hills stay beautiful.
WORDS: ASHLEY JOHNSON
PHOTO: JESSE BROWN NELSON