The Atacama Desert in Chile is on the wrong side of the Andes. The trade winds that might bring moisture from the east get caught in the mountains instead, making this the driest place on Earth. But this turns out to be perfect for the Atacama Large Millimeter Array—the most powerful telescope in history. At 5,000 meters—about as high as Everest Base Camp—the atmosphere is thin, and the heavens seem near.
The Chajnantor Plateau of the Atacama dwarfs the radio telescopes of ALMA, a project that began construction nine years ago and is still in progress. ALMA, a collaboration among scientists and governments from Europe, Asia, and North and South America, aims to gather a fuller view of the universe than has ever before been possible. Scientists and engineers work in the control room at ALMA. Radio frequencies received by the antennas are translated into data and carried by fiber-optic cables to the operations support facility. Because the site’s altitude is so inhospitable, the project’s roughly 600 workers—scientists, technicians, office staff, and construction workers—sleep in the living quarters at a more tolerable 3,000 meters. Only a few guards and those working overnight stay at 5,000 meters. Between 12-hour shifts, workers get some rest. In their off-time, workers dine with colleagues from the United States, Canada, Japan, Taiwan, Europe, and Chile. Workers stand inside the “receiver room” of one of the radio telescopes that make up the project. Massive warehouses provide shelter for both the equipment and the workers. Inside a warehouse, technicians work to assemble an antenna before it’s deployed. Workers test a radio telescope being readied for operation. A scientist performs some final tests in the receiver room before taking this antenna online. A radio telescope stands in the thin air of Chile’s Atacama Desert, ready to receive data from the stars.