Night-Shining Clouds at Peak Visibility
/ June 26, 2012
In both the Northern and Southern hemispheres, during their respective late spring and early summer seasons, polar mesospheric clouds are at the peak of their visibility, according to NASA's Earth Observatory.
These clouds are visible from aircraft in flight, the International Space Station (ISS) and from the ground at twilight, and typically appear as delicate, shining threads against the darkness of space — hence their other names of “noctilucent” or “night-shining” clouds.
These clouds are rare, but the chances of seeing them are increasing because they're forming more frequently and becoming brighter, according to Matthew DeLand, an atmospheric scientist with Science Systems and Applications Inc. and NASA's Goddard Space Flight Center who has been studying them for 11 years.