Banner image: The Milky Way stretches above Great Sand Dunes National Park and Preserve in Colorado. (Credit: National Park Service)

This month, Colorado recognizes its third Dark Sky Month, an annual celebration of getting away from city lights, lying under the stars and gaping at the vastness of the universe.

Such experiences are becoming harder to find today as streetlights, headlights, neon signs and more spread around the world. According to data from the citizen science project Globe at Night, the night sky is growing about 10% brighter on average every year.

But it’s not too late to experience the dark, especially in Colorado, said Erica Ellingson, professor emerita of astrophysical and planetary sciences at CU Boulder. Among other pursuits, she’s an expert in the field of archaeoastronomy, or the study of how ancient civilizations incorporated celestial bodies into their cultures.

Today, the organization Dark Skies International has certified 15 Colorado parks and towns as official Dark Sky Places. But you can still enjoy the night sky even if you can’t make it to one of these spots, Ellingson said. 

“The next couple of months with the good summer weather will be perfect for going out with friends, with family, with anyone really to share the spectacle of the sky,” she said. “The stars in Colorado are absolutely spectacular.”

She gives her take on what humans lose when we can no longer see the stars, and how beginners can jump into astronomy.

What is light pollution?

Light pollution is human-made lighting that, instead of providing light for all the useful things we have down here, gets thrown up into the sky. In most of the United States, and even worldwide, many people have never seen the Milky Way, or have never seen more than a few stars. We are losing a really, really old heritage—being able to walk outside and wonder at the stars.

Do satellites, like SpaceX’s Starlink satellites, also contribute to light pollution?

Yes, there are more and more satellites being launched every year. It’s becoming common for long telescope exposures to have a satellite streak on them, and they are noticeable in the sky even without a telescope. I’ve seen many Starlink “trains” shortly after launch. They look like a string of a dozen or more bright dots flying in a line across the sky. 

Where can people in the Front Range go to experience dark, or darker, skies?

Within the Front Range area, you’re looking for any place where you can get away from the dome of light around Denver, Boulder and some of the other larger cities. Sometimes, if you just go up the Peak to Peak Highway, the Flatirons in the foothills can block some of that light, and you can view darker skies. 

Rocky Mountain National Park doesn't have super dark skies because it's close to Denver, but it's certainly better than what you'll find in any of the cities or suburbs. 

How can beginners get into stargazing?

Connect with a community where there are people who are willing to share their star lore. Most cities in Colorado have a group of people who are telescope and astronomy enthusiasts. They often hold open houses called “star parties” where anyone is welcome. They'll bring out all their best telescopes and are happy to tell you everything they know about what's going on in the night sky.

Here on campus, the Sommers-Bausch Observatory holds Friday night open houses in the fall and spring when classes are in session. In the summer, they have a more reduced schedule.

How did ancient civilizations approach stargazing? 

We see some practical uses in many different societies—things like using the sun, the moon and stars as timekeepers, as calendars or guides for planting. 

But we also see people looking to the stars for power and mystery. We put the best of ourselves in the sky, the things that we value, the stories that are most powerful for our culture. All of these things we tuck up into the sky, and they're available for anyone to walk out of their house and look up and see.

It seems like the best part about stargazing is sharing it with other people. Do you agree?

I always ask my students at the start of the semester to tell me about experiences they had under the night sky. What strikes me most is that they nearly always say, “I was with my mom, my dad, my friends, my cousin, my partner.” Their stories involve who they were with and how they shared the sky together. 

This is a very ancient tradition, a very ancient feeling. The skies are filled with stories, filled with wonder that we should be sharing.