In June, when India and China had their deadliest military encounter in fifty years, the only weapons used were blades, rocks, and spiked clubs. The troops, who were forbidden from using firearms, were making an attempt at “mutual disengagement” in the Galwan Valley, a remote outpost in the region of Ladakh, the northernmost part of India. Twenty Indian soldiers were killed in the Stone Age melee, with an unknown number of Chinese casualties. Most of the Indian casualties had been pushed down a river gorge into icy water and died awaiting evacuation.
Ladakh is one of the most elevated areas on Earth, part of a region often called “the roof of the world.” Despite the perils that one might face there—altitude sickness, bitter cold outside of summer, and narrow roads prone to landslides—it is a place to behold. The slopes, a tie-dye of mineral hues, enclose iridescent, glacier-fed lakes. Overhead are some of the world’s clearest skies, spotless by day and crowded with stars by night. For centuries, the region was a crossroads for trading caravans and travellers from across Asia.
Today, the area is divided between India and its rival nuclear powers, China and Pakistan, each of which is accused of annexing territories there: Kashmir, Aksai Chin, Gilgit-Baltistan, and Tibet. Even in less tense times, Indian and Chinese troops stare each other down across the disputed border, known as the Line of Actual Control, or L.A.C., in carefully choreographed encounters. In May, before the battle at Galwan, rival patrols came to blows on the northern shores of Pangong Tso, the largest of Ladakh’s glacial lakes; a video of the incident went viral, showing men brawling against stark inclines. By the end of August, the skirmishes had moved to the lake’s southern shore. These landscapes, rendered digitally on Indian news coverage, seemed bare of natural or human life, and void of any purpose but as border, buffer, or battlefield.
On the southern shore of Pangong Tso, however, lies a group of pale structures that are focussed not on the ground but the sky. At their center is an aluminum shed built over a modest solar telescope. Throughout the recent skirmishes and during India’s months-long COVID-19 lockdown, this telescope has remained busy tracking solar flares. The observatory, which sits near the village of Merak, is one of two in Ladakh, both of which are situated on the Changtang plateau, just a few dozen miles from the L.A.C. The other, near a village called Hanle, was the highest observatory in the Eastern Hemisphere until a few years ago, when China built one higher, just across the border.
During the summer, Merak is thick with fields of barley. On any clear morning, Stanzin Tundup, a thirty-one-year-old with a face weathered by sun and dry wind, makes the short drive from his village to the telescope, where he parts the shutters and points the instrument’s lens at the sun. The telescope filters the light and isolates a wavelength known as H-alpha, a narrow band on which gargantuan movements of gas and energy, surging below the sun’s surface, come into view. On a recent visit, Tundup clicked open a file on a computer and pointed around a red stubbled image of the sun’s chromosphere. “We have this active region, so if we focus here, we have chances of solar flares and jets,” he said.
Until a generation ago, Tundup’s family, like many on the Changtang plateau, were pastoralists. “Everyone had their flocks, and they were nomadic, basically,” he said. “We didn’t have yaks, but we had sheep and goats, and, especially during holidays, I would go with my grandfather to take them into the high mountains.” The herds stayed for the summer, until his grandfather drove them down to warmer pastures. Tundup spent the winter skating on the frozen surface of Pangong Tso.
In 2006, when Tundup was seventeen, a team from the Indian Institute of Astrophysics (I.I.A.) arrived in Merak with a strange and lofty purpose. They wanted to build the world’s largest solar telescope there, in a village with no power and no phones, and which was reachable only by some of the highest motorable mountain passes in the world. To start, they installed the smaller pilot instrument that Tundup helps manage. The telescope was fabricated and tested in Nanjing, with the aid of the I.I.A.’s Chinese colleagues, before arriving at its home just outside the western limits of Tibet.
Today, the telescope’s readings are decoded by researchers in South India, but the device itself is supervised by young men and women from Merak. “This has been our philosophy,” G. C. Anupama, the dean of the I.I.A., which has its headquarters in Bangalore, said. “And it has a twofold advantage. Local people have pride in being involved in scientific activity—we’re not leaving them isolated—and then, in situations like today, they keep the observatories running. The data is still coming in. The science is not affected.”
In May, just days before the skirmishes around the lake began, India’s Ministry of Science and Technology reaffirmed its plans to build the bigger, two-metre National Large Solar Telescope. At the Merak site, Tundup keeps an architect’s drawing of what will be a six-story structure as his screensaver. He expects “the two-metre” to change his community without spoiling it, as mass tourism has done farther down the lakeshore. “In the coming years, I think this village will grow more curious, gain interest in scientific things,” he said. His hopes suggest a new vision for Ladakh, in which the region is defined not by war but by collaboration, scientific discovery, and inclusive development. “Once the two-metre comes, there will be lots of new jobs,” he said. “Merak will be famous, I think, like Hanle.”
In 1994, when teams from the I.I.A. surveyed Ladakh, looking for India’s clearest sky, they found a pristine site in Hanle. At the end of the Changtang plateau, an arid expanse turned into a sudden, flourishing wetland, with an elevated ridge at its center. The locals called the ridge Digpa Ratsa Ri. From its top, the encircling ranges lay low on the horizon, spanned by a perfect blue void.
The altitude and the surrounding plain meant that the Hanle sky excelled in two qualities: transparency and what astronomers call seeing. A sky is transparent when there is little to obstruct light. In Hanle, a girdle of mountains shuts out clouds and rain, and no town, industry, or highway exists to taint the air or brighten the sky. “Everything there looks closer than it really is,” Dorje Angchuk, the chief engineer of the Indian Astronomical Observatory, in Ladakh, said. You could drive toward an object, he noted, and never seem to be gaining ground.
The second quality, “seeing,” is good when light is minimally refracted by turbulence in the atmosphere. Usually, shifting bands of gases and aerosols cause light from the stars to zigzag. It is this effect that makes stars twinkle and that, for astronomers, tends to produce a blurred image. For the best transparency and seeing, you have to be outside the atmosphere altogether. This is why, in 2001, Frontline magazine called Hanle “the closest that India can get to possessing a space telescope, for now.”
The Hanle telescope was named the Himalayan Chandra, after the astrophysicist Subrahmanyan Chandrasekhar, who won a Nobel Prize in 1983. Besides having access to clear skies, the telescope is valuably positioned on the other side of the planet from the major observatories in the West, like those in Hawaii and Chile’s Atacama Desert. As the Earth turns, objects set in the Western sky and rise into view in Asia. “Take a supernova,” Anupama, of the I.I.A., said. “It has had an explosion and it’s fading. It’s a temporal evolution.” These events, called transients, need to be tracked by telescopes situated around the world. According to Anupama, the Chandra telescope “bridged the gap between telescopes in Australia and in the Canary Islands.”
Since the Himalayan Chandra opened, in 2000, other telescopes have come to crowd around Digpa Ratsa Ri, constructed, in stages, in the brief thaw between Ladakh’s long winters, when temperatures can fall to minus twenty degrees Celsius. The Major Atmospheric Cherenkov Experiment, or MACE, Telescope, built by India’s premier nuclear-research center, is to be the second-largest gamma-ray telescope in the world. And the Indian Space Research Organisation—the country’s NASA-equivalent—plans to add a telescope to monitor space debris and safeguard India’s ambitious satellite program. As the Hanle complex expands, it will study most every part of the sky, from orbital space, just above the Earth, to supernovas and blazars in other galaxies.
Since 2012, the Hanle observatory has also had company across the border. That year, the Chinese Academy of Sciences established its own observatory in the district of Ali, barely seventy miles away—and nearly two thousand feet higher than Digpa Ratsa Ri. The news caused a brief flap in the Indian media, which claimed that Ali was in Aksai Chin, a region that India considers sovereign territory. When it turned out that Ali was in Tibet, the issue was forgotten, though not by Hanle’s astronomers.
The Ali observatory’s most sophisticated project, the C.M.B. Polarization Telescope, is set to open this year. The telescope, which cost tens of millions of dollars, will search for primordial gravitational waves to advance our understanding of the very early universe—the moments just after the Big Bang. The project exemplifies China’s ambition to turn the vast Tibetan plateau into “Asia’s Atacama” and to move to the fore of global astronomical research. That vision will be difficult for India to match. “We can’t really project Hanle that way, because of our current infrastructure here,” Anupama said. “But I hope that in the years to come, Hanle will be competitive—and be seen as a better site.”
And yet, when it comes to the sky, the two countries enjoy a warmer relationship than their strategic rivalry might suggest. For the past decade, both China and India have leveraged “astro-diplomacy” to forge international ties and boost their scientific standing. In 2014, the nations deemed astronomy an area of collaboration, committing mutual support to projects like Merak’s solar telescope. Many I.I.A. graduates now accept postdoc appointments at the Chinese Academy of Sciences, and senior faculty from both institutions co-author papers. India and China are also partners in a five-nation effort to build a Thirty-Metre Telescope (T.M.T.)—an instrument three times bigger than any telescope in existence—in Hawaii. Every few weeks, astronomers in Bangalore and Beijing video-conference with colleagues in the United States, Japan, and Canada to grapple with the T.M.T.’s challenges. If completed, the telescope will enable the most powerful observations ever made of the northern sky.
In January of 2019, the administration of Prime Minister Narendra Modi surprised Indian astronomers by announcing a plan to build the world’s largest solar-power plant in the Hanle plain. A plant of that size would mean lights, construction, and a transformation of the local climate—in short, the blinding of Hanle’s telescopes. A professional telescope is, by necessity, an introvert. To function well, it has to either retreat from society or ask nearby humans to tone it down.
In Hanle, the only nearby humans reside in a few hamlets and in the storied Hanle Gompa, a seventeenth-century Tibetan Buddhist monastery. Early on, Hanle’s head monk granted permission to shift a stupa from the highest point of Digpa Ratsa Ri, and the Dalai Lama later performed the Himalayan Chandra’s consecration ceremony. Since then, the locals and astronomers have found a quiet equilibrium. The telescopes have brought a road, good jobs, and a discreet brand of tourist to the area. Like Stanzin Tundup, in Merak, Hanle residents want to see astronomy prosper. The field promises high-value employment that depends on sustaining older life styles, rather than displacing them.
Since the government’s announcement, Hanle locals, astronomers, and wildlife officials have been lobbying to relocate the solar plant. “We are still grappling with it,” Angchuk said. “What we are watching is so far away that even a small light thrown at the sky will degrade conditions.” The plant threatens not just India’s clearest sky but the pastoral communities and wildlife below it. Newly alert to the threat of development, the I.I.A. and the district council proposed to do what India had never done: create a sanctuary for darkness.
The idea that a clear night sky might represent a natural heritage, and one worth defending, is relatively new—and not just in Ladakh. In the past few decades, an international movement has begun advocating for protected areas, free of light pollution. In 2007, the UNESCO-sponsored La Palma declaration asserted humanity’s “right to starlight,” and, that year, the first international dark-sky reserve was recognized, in Quebec. Most dark-sky areas are meant to protect telescopes, including the Ngari Dark Sky reserve, around China’s Ali observatory. At nearly a thousand square miles, the reserve is one of the largest of its kind; within its borders, all artificial light is carefully regulated. The proposed Hanle sanctuary would have a thirty-mile radius—three times larger than its Chinese counterpart. “The Ngari Dark Sky reserve and the Hanle Sanctuary, combined, could give our astronomy a big boost,” Angchuk said. Together, he believes, the sanctuaries would even protect an ecological and cultural heritage on the ground.
The symmetry is moving: two reserves for the stars, established on opposing sides of a hostile border. In both India and China, any advocacy for dark skies comes up against the logic of industrial development. Astronomers on either side of the L.A.C. could use each other as leverage to make that advocacy stick. And they could advance the idea, already present in Ladakh, of a gentler rivalry, one driven by science, local partnerships, and the impulse to widen our window onto the cosmos. “The universe is too large,” Angchuk said. “We can both go together.”
