During the summer, observers can sometimes see beautiful clouds called “night-shining” clouds, or noctilucent clouds. And while lucky observers were seeing from below this summer, a NASA satellite was watching them from above.
Noctilucent clouds form in an upper layer of the Earth’s atmosphere called the mesosphere during the Northern Hemisphere’s summer – at an altitude of 80 km (50 miles). They can start forming as early as May, and extend through August. They can also be seen in high latitudes during the summer months in the Southern Hemisphere.
The images were gathered by NASA’s AIM satellite (aka, Aeronomy of Ice in the Mesosphere), which snapped pictures of the clouds on May 25th, 2007.
A puzzling aspect to the phenomenon is that it’s changing dramatically. The clouds are growing brighter, seen more frequently, and visible at lower and lower latitudes than ever before. AIM will observe the clouds above the Earth’s poles for two complete clouds seasons, documenting their entire life cycle to try and help uncover an explanation for this mystery.
Original Source: NASA News Release