Chinese astronomers hope to establish a major observatory program on the roof of the world, the Tibetan Plateau, with new research arguing for pristine observing conditions nestled in the uplands.
The analysis focuses on a study site near Lenghu Town in Qinghai Province at an altitude of more than 2.5 miles (4.2 kilometers) and some 1,900 miles (3,000 km) west of Beijing. In the paper, the scientists argue that three years of monitoring shows conditions on par with those at some of the most renowned scientific outposts on Earth. Moreover, making use of the site would fill a gap in scientists' existing global network of high-altitude, high-caliber observatory complexes, allowing for more reliable monitoring of phenomena that change rapidly, like supernovas. Right now, top-tier observatories cluster in the Western Hemisphere — think Maunakea in Hawaii, Cerro Paranal in Chile and La Palma in the Canary Islands.
"Finding a good site in China, spatially on the Tibetan Plateau, is essential to the development of astronomy and planetary science in China," co-author Fei He, an optics specialist at the Institute of Geology and Geophysics of the Chinese Academy of Sciences in Beijing, told Space.com in an email.
The initiative tracks with China's heavy focus on building new science and technology facilities around the world, Dean Cheng, an expert on Chinese military and space activities at the Heritage Foundation, a conservative public policy think tank based in Washington, D.C., told Space.com.
"Astronomy is a high priority," Cheng said. "Both inside and outside China, they are busily improving their space surveillance capabilities, space observation capabilities, but also their scientific capabilities as we've seen with their missions to Mars and the moon."
The site analyzed in the new research is located on the Tibetan Plateau but not in Tibet proper, which China invaded in 1959 and where tensions continue to run high. Qinghai Province is next door, but about a quarter of its population are Tibetan, according to China's government press agency Xinhua.
And while the research was only submitted this February, observatories are already in the works at the site, according to Xinhua. The news bureau announced in April 2020 that a Chinese university and the regional government had agreed to terms for the construction of the Wide Field Survey Telescope (WFST), a 2.5-meter optical telescope at the time scheduled to begin work in 2022.
Before focusing on the site near Lenghu Town, the scientists behind the new research set up equipment at three additional locations during early stages of the research, between 2016 and 2018. But Lenghu Town was a particularly appealing site, He wrote, and somewhat connected to the urbanized coast on the other side of the country.
Plus, local government officials invited the team in to conduct the analysis. "Lenghu has been known to have unusually clear sky to the community, and at the same time, Lenghu area has a spectacular landscape similar to Mars, therefore the local government wanted to develop tourist industry specialized in astronomy and planetary science," He wrote.
So He and his colleagues took to trekking out to the site, which is located on Saishiteng Mountain at an altitude of about 13,800 feet (4,200 meters), about 200 feet (60 m) higher than the Keck Observatory in Hawaii. The site's elevation is key: Earth's atmosphere causes blurring in astronomical observations and the higher a telescope's site is, the less atmosphere instruments must see through.
Other factors also appeal to the team from the new analysis. The sky is relatively dark, and Lenghu officials have already created regulations to keep background light low. According to 30 years' worth of weather records studied by the team, the site sees just 0.71 inches (18 millimeters) of precipitation a year and 3,500 hours of sunshine. And the team's analysis of factors like air stability, turbulence and water vapor, are also promising, according to the researchers.
Of course, the elevation and remoteness that fosters such dark skies are also logistical challenges.
"Before the road reached the summit of Saishiteng Mountain, the necessary building materials and tools were carried to the site by a helicopter and the scientific devices were manually carried up to the mountain," He wrote. One team member saw wolves and thick snow was a regular challenge.
That's not likely to foil plans to build observatories. Currently, China is quite focused on construction on the Tibetan Plateau, and particularly in Tibet itself, which in addition to its own restiveness is a key strategic region given China's tensions with nuclear-armed India, Cheng noted.
"They're on top of the world at the top of the Himalayas," he said. "The Chinese are building massive infrastructure — roads, railways, air bases, military bases, camps — and moving in a lot of military equipment."
Between trips up the mountain, team members talked with local residents of Lenghu Town. While the authors noted that local officials were enthusiastic about the prospect of welcoming astronomy to the site, it's not clear whether residents agree.
He said that about 3,000 people live in the town, which is located about 50 miles (80 km) away from the analyzed site. "What we usually talked about is how the development of astronomy and planetary science at Lenghu could make their lives better," He wrote of conversations with residents.
"Scientific development will attract more tourists here and promote the development of local tourism, so they can make more money," He wrote. "During the night, when walking on the street, we also introduce the stars and planets to them and what kind of tourism can be developed. At the same time, we also talked about the protection of the dark sky which is essential to the development of the observatory, and they were happy to make sacrifices for it."
Some of those sacrifices are already in action. "If the local population were to grow with economic development, then control of light pollution could be lost," the authors wrote in the paper. But Lenghu leaders knew that going in and passed strict dark-sky protections in 2017 to avoid that threat — part of what has made the site so appealing for the researchers, they wrote.
And the result is stunning. "When you are on the summit of the mountain, you can see the fantastic Mars-like landscape of the Qaidam Basin during the day, and the magnificent and beautiful starry sky during the night," He wrote. "It was very memorable."
The research is described in a paper published Wednesday (Aug. 18) in the journal Nature.
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