Like a peaceful scene from a Star Wars movie, the European Southern Observatory’s La Silla telescopes sit blanketed in fresh snow as the sun sets.
The characteristic domes of the telescopes are closed off to protect the instruments from the harsh environment of the Atacama Desert. But how come one of the driest places on Earth, where temperature rarely drop below 0C, is covered with snow? ESO explains:
The dry air of the region plays a large part in this phenomenon. In dry conditions, snowflakes form and as they drop a small amount of evaporation occurs. This process removes heat from the snowflake, keeping it cold enough to survive the descent into a region where the temperature is above freezing. In short, the lower the humidity in the atmosphere, the higher the temperature at which it can snow — and so we can find snow in the Atacama Desert.