An annual atmospheric phenomenon called noctilucent clouds returned in late November 2013 to settle over the South Pole.
The clouds, which glow an electric blue, are the highest on Earth. They typically form 52 miles above the planet at the edge of space, according to NASA. The agency is using a satellite called AIM (Aeronomy of Ice in the Mesosphere) to study the formations, which are the result of sunlight hitting the ice crystals that make up the clouds. They usually appear from November to February, during the Antarctic summer, and shift to the Arctic from May to August.
Watch the NASA video to find out more about noctilucent clouds and how climate change is increasing their range.