Nubes mesosféricas vistas desde la ISS a 76-85 km de altura (NASA).
Polar mesospheric clouds in the Northern Hemisphere are featured in this image photographed by an Expedition 31 crew member on the International Space Station. In both the Northern and Southern Hemisphere, during their respective late spring and early summer seasons, polar mesospheric clouds are at the peak of their visibility. Visible from the ground during twilight, aircraft in flight, and the International Space Station, they typically appear as delicate shining threads against the darkness of space hence their other name of noctilucent or “night-shining” clouds. Polar mesospheric clouds form between 76-85 kilometers above the Earth’s surface, when there is sufficient water vapor at these high altitudes to freeze into ice crystals.