A NASA satellite has captured its first images of noctilucent clouds, brightly lit night-time clouds that form high in Earth's atmosphere during each hemisphere's summer.
The night-shining clouds form between May and September in the northern hemisphere. Very little is known about how they form, or why they are appearing more regularly, and at lower altitudes.
NASA says that now its Aeronomy of Ice in the Mesosphere (AIM) mission is in place, it is seeing them more frequently as the summer season progresses.
More: http://www.theregister.co.uk/2007/07/02/shiny_clouds/
...and some pretty piccies not directly associated with the report: http://www.philhart.com/gallery/Astrophotography/Noctilucent_Clouds/
...and keep an eye out from Orpington too. If the rather lower solid grey overcast ever breaks...