Our nights are getting brighter, and Earth is paying the price

Some areas of upper New England are sparsely populated, meaning that light pollution is low and skies are among the darkest in the U.S. Here, stargazers gather in Maine for an annual summer star party known as Astronomy Retreat. The long-exposure image captures star trails produced as Earth rotates, pinpointing Polaris, the north star, in the centre.

Photographer Babak Tafreshi stands under the star-filled Death Valley sky. The International Dark-Sky Association notes that the park “is largely free of its own sources of light pollution but the lights of distant Las Vegas and other cities have an impact on the park’s skies and desert nightlife.

Stargazers flock to Death Valley during the park’s Dark Sky Festival, where rangers, scientists, and amateur astronomers help bring the nighttime skies to life.

Above the palm trees of Death Valley’s Furnace Creek, Sirius, the brightest star in the sky, twinkles on the left while the constellation Orion emerges from the darkness on the right. Truly dark skies are studded with so many stars, it can be difficult to pick out even familiar constellations.

Cheryl Wilcox of the Riverside Astronomical Society points her telescope into the star fields twinkling above Death Valley National Park during its annual Dark Sky Festival. “The skies there are affected by only the smallest amounts of light pollution,” writes the International Dark-Sky Association, which gave the park its highest-level designation in 2013.

Astrophotographer Oshin Zakarian enjoys a view of Venus, Jupiter, and our moon in the desert twilight. Under clear, dark skies, the human eye can make out a wealth of astronomical objects—including other galaxies such as our neighbour, Andromeda.

A Sky Quality Meter sitting in Death Valley reads the night sky brightness. In this case, the number indicates darkness directly overhead that's deep enough to achieve a gold or silver rating from the International Dark-Sky Association. The glow along the horizon is not a city, but the cosmic illumination of zodiacal light.

Photographer Babak Tafreshi stands under the star-filled Death Valley sky. The glow of city lights from Las Vegas, 90 miles away, and Los Angeles, 170 miles away, creates the appearance of a double sunrise on the horizon.