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Earth Notes: Rainbow Bridge A Dark Sky Sanctuary

Tom Till Photography

Rainbow Bridge National Monument in southern Utah is a place where Earth and sky meet, connected by a giant natural stone arch. By day the archway echoes the shape of a rainbow: by night, it mimics the Milky Way.  The monument is also a certified International Dark Sky Sanctuary, a designation reserved for rare, remote locations with little or no light pollution. There are only ten such sanctuaries in the world, four of them in the United States.

Three hundred feet tall and almost as wide, Rainbow Bridge was carved by water. Several million years ago the Colorado Plateau began to rise and rivers cut deeper into the steep terrain. One creek dashed against a fin of Navajo sandstone that blocked its path. In time it cut a hole through the rock.

It’s a sacred place to Hopi, Zuni, Paiute, Ute, and Navajo. Diné creation stories tell of a rainbow turned to stone to serve as a safe pathway over a river. The bridge is listed in the National Register of Historic Places for its cultural significance. Indigenous people perform ceremonies there for protection, blessing, and rain.

For most of its history, Rainbow Bridge could only be reached by a long, difficult trek through the desert. That changed in the 1960s and 70s, when Lake Powell filled behind Glen Canyon Dam. Now about a hundred thousand visitors come to the national monument every year, mostly by boat.

But it’s still isolated enough to earn recognition from the International Dark Sky Association for its starry skies. While Rainbow Bridge is one of dozens of other dark sky places on the Colorado Plateau: its designation as a dark sky sanctuary is special.

This Earth Note was written by Melissa Sevigny and produced by KNAU and the Sustainable Communities Program at Northern Arizona University.


Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.