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Today’s Picture of the Week features two distinct families: a collection of ALMA antennas and a trio of vicuñas , a type of camelid, related to llamas and alpacas. Unlike in almost every way, the subjects of this image are linked by their extremely hostile home environment, high up in the Chilean Andes.
The Chajnantor plateau, site of the Atacama Large Millimetre/submillimetre Array (ALMA) shown here, is 5000 metres above sea level, making it one of the driest places on Earth. The aridity is perfect for observations with ALMA, which searches for cosmic signals from the cold Universe that are readily absorbed by moist air. But the low number of cloudy days, along with a thin atmosphere, produces harsh conditions, pushing the limits of both engineering and evolution.
The ALMA receivers –– the devices that catch signals from space –– are enclosed in cryostats that keep them very cold, protecting them against the drastic day-to-night temperature swings of the desert. The antennas are designed to withstand extremely strong winds, up to 100 kilometres an hour. ALMA’s electronics are cooled with extra-fast spinning fans to account for the thinner air. For the workers, like technicians and engineers who maintain the site, portable medical oxygen is mandatory on the plateau to limit the risk of high-altitude sickness.
Like ALMA, vicuñas, are also well-suited to these extreme conditions. They have several adaptations to cope with low oxygen density, including an increased ability to bind oxygen to red blood cells and hearts 50% heavier than similar-sized mammals. Vicuñas are also protected from large temperature variations with their dense fleece of fine hairs, which traps warm air to insulate them during cold nights and forms a breathable barrier to prevent overheating during the day.