Question: What seemingly alien landscape did scientists deem so boring that they built the world’s biggest observatory on it?
Answer: Chile’s Atacama Desert
In the Atacama Desert, a whole lot of nothing can be a good thing. With 41,000 square miles of extremely arid landscapes from the Andes to the Chilean Coast Range, the Atacama is striking not just for its Mars-like looks but its vast emptiness. Its near-complete isolation and lack of activity might make it a less-than-ideal place to live—but it is catnip for astronomers.
With its 16,500-foot altitude placing it above much of the rest of earth, next-to-no cloud cover, and no nearby cities that might cause light pollution, Atacama offers the ideal conditions for an observatory; and with so few humans living in the region, there is the added bonus of no radio interference.
The 16-nation European Southern Observatory research group (known as ESO) joined forces with the U.S., Canada, Japan, South Korea, Taiwan, and the host country of Chile to build the Atacama Large Millimeter Array (ALMA), the largest and most expensive observatory on earth, in this environment. Costing 1.5 billion dollars, the observatory is composed of 66 radio telescopes as tall as 39 feet high. Reading both millimeter and submillimeter wavelengths, ALMA is meant to be able to record images of star and planet formation, including star birth from eons ago. It opened in 2011 and new operations continue to be added with each passing year.
Since it kicked into gear, ALMA has become a scientist magnet. In a part of the world that once only drew adventurous travelers eager to see the most alien landscape on earth, researchers from the worlds of astronomy, physics, and planetary sciences have been flocking to Chile. The boom in scientific visitors to ALMA and a dozen other observatories in northern Chile has yielded a new term: Astrotourism.
How Dry is Dry? Hyper-Arid Atacama
- Falling between two high mountain ranges means that the Atacama enjoys a double “rain shadow,” which is when high peaks act as a barrier to rain-bearing winds.
- Outside polar regions, the Atacama Desert is the driest place in the world. The average rainfall is just over a half inch per year, though some villages report as little as 1/20th of an inch annually.
- Stretches of as long as four years have passed with no rain in the central Atacama. At least one of the weather stations has never recorded any rain at all.
- Geological evidence shows that the Atacama has been hyper-arid for at least three million years. More recent recorded weather reports suggest that there was almost no measurable rainfall from 1570 to 1791.
- In some parts of the Atacama, the only moisture is a fog known as camanchaca, which does not produce raindrops.
- It is so dry that NASA uses the Atacama Desert to try out instruments for future Mars lander vehicles.
- As the climate changes, exceptions to the aridity norms do occur: in 2011, an Antarctic cold front crossed the rain shadow and dumped 31 inches of snow on the plateau, and there were floods in 2012 and 2015, natural events once unthinkable.
Marvel at the rare terrain on earth that can truly be called otherworldly when you explore Chile: From the Atacama Desert to the Patagonian Fjords.