Eerie polar mesospheric clouds have been captured by the astronauts on board the International Space Station.
Viewed from the ground, the ‘ragged edges’ of this cloud layer are known as noctilucent clouds – which means ‘night shining’ clouds.
As their name imply, these glowing clouds form over the planet’s north and south poles, at mesospheric heights (80 to 100 kilometres above the ground). The thin, wispy layer of ice crystals that they’re composed of is virtually invisible during the day, when the sunlight is shining down through it. However, as the Sun is setting, and the rays of light from it strike this layer of ice crystals edge-on, the effect is quite spectacular.