• Mon. Oct 26th, 2020

Dimancherouge

Technology

The Clear Night Sky Over India and China’s Hostile Border

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.

This pilot telescope, in Merak, is a test run for India’s quest to build one of the world’s largest solar telescopes. This instrument was built in Nanjing with the help of Chinese scientists.Photograph by Anmol Tikoo

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.”

Some of the Changpa, the indigenous people of the Changtang plateau, remain pastoralists, herding yaks, sheep, and prized pashmina goats, which produce some of the finest wool in the world.Photograph by Dorje Angchuk

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.”

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