A key ingredient of Earth's strangest clouds does not come from Earth. New data from NASA's AIM spacecraft shows that "meteor smoke" is essential to the formation of noctilucent clouds.
FULL STORY: http://science.nasa.gov/science-news/science-at-nasa/2012/07aug_meteorsmoke/
VIDEO: http://www.youtube.com/watch?v=Qzs9ZOsjF-c
