’Night-shining’ clouds seen from Earth and space

Noctilucent clouds float much higher than other clouds, allowing them to shine when the sun is below the horizon –" see a gallery of the mysterious, shimmering clouds here

http://feeds.newscientist.com/c/749/f/10898/s/63e4298/l/0L0Snewscientist0N0Cgallery0Cnoctilucent0Eclouds/story01.htm