Tyler Nordgren, the author of "Stars Above, Earth Below" talks about the night sky and what it means to be an International Dark Sky Park. Nordgren, who is an archaeoastronomer, has traveled around the National Park System documenting the night skies. He also serves on the board of directors of the International Dark Sky Committee, a nonprofit that works to preserve the nighttime skies. 

1. What exactly is archaeoastronomy? 

Archaeoastronomy is trying to understand the astronomy of ancient peoples and how they related to the sky. Even today, our holidays have a connection to astronomy. Easter, for example, is the first Sunday of the first full moon after the spring equinox.

2. How did you first become interested in archaeoastronomy? 

Nordgren said Chaco Culture National Historical Park was the reason he decided to become an archaeoastronomer. He first learned about Chaco from Carl Sagan's TV series "Cosmos." That when he says he realized astronomy, by its very definition, is what made people human.

3. What is your favorite star formation? 

Nordgren says he loves the summer sky and the Milky Way. Once while he was out at Bryce Canyon National Park, someone approached him and said, "It's beautiful, but a shame about the fires." There were fires burning in Arizona, so Nordgren nodded. But the woman was looking at the Milky Way. It actually looked like big clouds of smoke rolling around.

4. How does a place receive International Dark Sky designation? 

First someone nominates the park, monument or preserve. Applications then are sent to the International Dark-Sky Committee. The area must show it is preserving the dark sky and is engaged in education about the night sky. One or two places receive the designation each year. There are 13 designated sites around the world, including Chaco. Most are in the U.S.

5. How does the dark skies designation benefit the surrounding communities? 

Natural Bridges National Monument in southeast Utah, the first place to receive designation, saw an increase in tourism after getting the label. Because there are few camping spaces at the monument, the majority of the tourists go to neighboring towns to stay in hotels, which benefits the local economy.