Night shining Noctilucent clouds, also known as Polar Mesospheric Clouds or simply NLCs became quite a feature of this blog when they began to illuminate Kendal during the summer viewing season. These clouds of thin layers of ice particles are the highest of the three cloud layers. As such, they tend to be illuminated when the Sun is an hour beyond sunset or before sunrise. They form at high latitudes and have been linked to emissions from volcanoes and even space travel.
To better understand these enigmatic things, NASA launched a sounding rocket called CARE, the Charged Aerosol Release Experiment. The exhaust of the fourth stage of the rocket will be blasted out at the correct altitude to form an NLC that should be detectable days to months after the initial release. Ground based observatories will join with the STPSat-1 instrument Spatial Heterodyne IMager for MEsospheric Radicals, or SHIMMER, which often observes natural NLCs, to keep a careful watch on developments. This will be the first observation campaign involving space based watches on artificial NLCs. The experiment has already created something of a stir, with UFO reports across the US sparked off by the launch.