By Gabby Sherwood
Each summer, Rocky Mountain Conservancy supports ranger-led night sky and astronomy programs in Rocky Mountain National Park (RMNP), which attract people of all ages to gaze up in wonder at the stars and learn that one of the secrets to protecting their favorite plants and animals in the park, takes place after dark.
RMNP Night Sky Ranger Lead Danielle York’s goal for these programs is for visitors to not only have a positive, inspiring experience under the night sky in Rocky, but use what they learn to protect night skies in their home areas.
Why do dark night sky conditions matter?
This is one of York’s favorite questions. In Rocky, “dark night skies are critical to the ecology of a particular area,” said York. “When species have access to dark night skies, it helps maintain their natural rhythms of getting food, migrating, and mating.”
Just one artificial light source at night can cause rippling effects in areas of the surrounding ecosystem. Take bats for example. Their eyes need to be in naturally dark conditions to hunt at night. One of their food sources, moths, is attracted to light. So, when moths leave dark areas to be close to lights turned on at night, bats are forced to leave their natural dark habitat to find food, making them more vulnerable to predators.
“Light pollution at night is artificially produced light that is impeding the natural functions that would be happening in that place,” said York. It’s also any light not facing directly down, “registering in our eyes as glare and prevents us from seeing so many details we would normally be able to see at night.” This includes the brightness, definition, and quantity of stars.
Did you know that the glow from cities can typically be seen in the sky within at least a 100-mile radius? In areas of Rocky, the light domes from cities nearby like Fort Collins, Loveland, Longmont, and Denver can be seen brightening the horizon.
Humans also need the cycle of dark skies and bright days to keep our circadian rhythms in sync. “We need to sleep in naturally dark conditions for multiple hours of the night for most nights of the month,” said York. “That is when our bodies produce some of the hormones needed for things like fighting cancer. Something as simple as sleeping in the dark benefits a person’s health for their entire lifespan.”
There is a simple yet effective way to make a difference in helping protect night skies:
- Reduce the amount, duration, and intensity of light used outside at night.
- Turn off a porch light when it’s not needed.
- Close the blinds in the house.
- Use a lower powered or red-light flashlight when grabbing something from the car.
Next time you gaze up in wonder at the stars in Rocky, remember that while many views of the park have changed throughout time, the night sky has not. “Night skies are independent of climate change, forest fires, and human development,” said York. “It is special that we are able to connect with the exact night sky views that people thousands of years ago would have seen from this exact location.”