Exploring the heavens from high desert in Chile
We rolled into San Pedro de Atacama, Chile, at 9 a.m. and it was as if we were transported back in time 150 years to a cowboy town along the Arizona-Mexico border. The buildings were adobe, with straw sticking out of the bricks, windows and doors shuttered tight. Sand from the Atacama Desert, the largest sand desert in the world, made the roads appear unpaved. I expected the spirit of John Wayne to appear around the next corner.
This is where ALMA lives. ALMA is the Atacama Large Millimeter Array, an enormous field of 66 mammoth radio telescopes, each weighing 100 tons, in a basin 15,000 feet above sea level.
The village is surrounded with archaeological, geological and astronomical delights. Mummies 2,000 years older than those found in Egypt. Tectonic plate movement in the “pushed up” mountain structures exposing eons-old sedimentary earth strata. Volcanos punctuate the landscape. A finger of smoke from Volcán Lascar, like a burning fuse, escapes from the cauldron of lava churning below. The arid skies offer an unrivaled view of the cosmos.
These attractions and more bring people from around the world to swell the sleepy pueblo of 2,000 residents into a bustling oasis. The town wakes up at noon, stretches and takes a nap at 2. At 5, it bursts open with restaurants, shops and music. Tour companies are busy scheduling excursions to Valle de la Luna, Death Valley, geysers heated by volcanic heat, archaeology sites and nighttime astronomy outings.
Unlike optical telescopes, which work only at night, ALMA operates 24 hours because it “sees” electromagnetic waves, not light. There are other radio telescopes, including Kitt Peak outside of Tucson. But ALMA is unique. It was conceived by astronomers of international fame to define the ideal facility. When there was a consensus, they found the ideal location: 50 kilometers from San Pedro de Atacama.
ALMA installed the first antenna in 2003, began extensive observations in the second half of 2011, and the last antenna joined the group in 2013.
Carl Sagan said: “Somewhere, something incredible is waiting to be known.” He died before the first ALMA antenna was in place, yet ALMA is fulfilling his dream. No other observatory has discovered so much in so little time about the universe in which we live.