Grand Sky over Grand Canyon

Most visitors see the Grand Canyon by daylight and are gone by dark, so they miss the other half of it. Every June since 1991 astronomers have set up telescopes on both rims for a week-long star party, and in 2019 the park was certified as an International Dark Sky Park after years of retrofitting its lights.

Below the stars, the canyon keeps a longer count. The Colorado River has cut it in the last five to six million years and runs 277 miles through it. The rim rock, the Kaibab, is about 270 million years old. The dark rock of the inner gorge is close to two billion.

The pointed buttes inside the canyon are called temples. The geologist Clarence Dutton started that in 1880, when he named Vishnu Temple for its likeness to a pagoda. Brahma, Zoroaster and Shiva followed, and the names stuck.

This picture is square and almost entirely blue. The Milky Way rises from the upper left and spills down toward the center, threaded with dark dust. Under it a line of temples steps down in stacked ledges, their edges touched with faint warm light, and the far rim runs flat across the horizon. It reads best in a dim room, where the blues go deep.