The Sinking Moon

The moon appears to swim in the dry Atacama Desert

Credit: P. Horálek/ESO

ESO Photo Ambassador Petr Horálek takes this striking image of a ’swimming’ moon in the Atacama Desert in Chile. The Atacama Desert is known as the driest non-polar place in the world with soil that has been compared to that of Mars.

When the moon is high it has a crescent shape; as it slowly descends into the horizon, the shape is distorted due to the refraction of light as it passes through layers of different air densities. As it disappears into the horizon making for a “rare theatre”— as described by Horálek— the moon appears to look like a zig-zag shaped-line and appears to “swim”.