An astronomical antenna

The mammoth 12-metre (39 ft) dish of an Atacama Large Millimeter/submillimeter Array (ALMA) antenna glistens in the sunlight atop the Chajnantor Plateau, high in the Chilean Andes.

The most visible part of each ALMA antenna is their dish, which consists of a surface of metallic panels. This large reflecting surface plays the same role as the mirror of an optical telescope: it collects radiation coming from distant astronomical objects, and focuses it into a detector that measures the radiation.