It’s not unusual to spot clouds in the night sky, but to capture ones with an electric blue tint are another story. The clouds you see above were captured by photographers in the North and South pole regions. There are various theories that “associate them with meteoric dust, rocket exhaust, global warming – or some mixture of the three.” Continue reading for a video, more pictures, and additional information.

Video

While the exact cause for the formation of polar mesospheric clouds is still debated – dust from meteors, global warming, and rocket exhaust have all been suggested as contributor – recent research suggests that changes in atmospheric gas composition or temperature has caused the clouds to become brighter over time. Space Station astronauts also captured images of the clouds earlier this month as the craft passed over the Tibetan Plateau.

Pictures

[Sources 1 | 2]