This story was published August 5, 2022 by Grist

The beginning of the night at the McDonald Observatory can be frantic. Jason Young, a visiting lecturer in astronomy at Mount Holyoke, starts by tracking the steadiness of the atmosphere, looking at “standard” stars to calibrate the Harlan J. Smith Telescope. He makes sure the telescope’s iconic white dome stays on track, checks that there are no stray lights in the dome that could mar data collection, and finally, watches for clouds. By midnight, he settles into the telescope’s top floor control center, alone in a pool of light from two huge computer monitors. 

“It’s a marathon, not a sprint,” said Young. “But if everything goes smoothly, then it’s pretty easy to just keep an eye on things.” 

The observatory is located in the Davis Mountains, high above the Chihuahuan Desert. By day, the isolated West Texas mountain range is striking, ornamented with dark clumps of oak, pinion, and juniper scattered across the gold and khaki grasslands. At night, clear skies reveal endless trails of stars.

Young is observing LEDA 1562327, a diffuse spiral galaxy interacting with a second galaxy that, in his words, are going through a “weird phase” in their evolution: They have enough gas to form stars, but for some reason, aren’t. Meanwhile, next door — astronomically-speaking — two similar galaxies are colliding, forming stars at a rate of nearly 100 per year.

“It’s like a quiet cottage right next to a rock concert,” said Young. “So, I’m trying to figure out why these two are not doing anything when the neighborhood seems to be very active.”

Until a decade ago, the Davis Mountains were one of the darkest places in North America, which is why in 1933, the University of Texas established the observatory on Mount Locke, and later, expanded to nearby Mount Fowlkes, taking advantage of the clear night and high altitude. The observatory’s biggest project for the last four years has been HETDEX, the Hobby-Eberly Telescope Dark Energy Experiment, created to map the night sky out to 11 billion light years in order to figure out why the universe is expanding as it ages. 

Clear, dark skies are a resource and key to doing astronomical work, but growing sources of artificial light threaten the night. The McDonald Observatory is situated at the southern edge of the Permian Basin, one of the largest oil fields in the United States. In 2016, with the adoption of hydraulic fracturing and other drilling technologies, oil and gas production in the region increased dramatically. The boom brought thousands of well pads, midstream facilities, flare stacks, and traffic, filling the night sky with artificial light, easily seen by the naked eye as “skyglow,” a massive dome of orange glare on what was once an almost dark horizon.

The sudden spike in oil and gas drilling came with a nearly 60 percent increase in light pollution at the observatory, threatening the work McDonald has been conducting for nearly a century. Some 100 miles to the north, on the northern edge of the Permian, Carlsbad Caverns National Park in New Mexico noticed a similar change: “They had a 710 percent increase in light pollution in about eight years,” said Stephen Hummel, the Dark Skies Initiative Coordinator at McDonald. In 2020 alone, production in the Permian accounted for 30 percent of all crude oil production and 14 percent of the country’s natural gas production.

“Seeing the real sky, the old-fashioned way, is still important,” said Hummel. “There should be places left … that we can preserve where people can go and experience the night.”

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