Didn’t know the things existed. They kinda look like ghosts in the sky or something of that nature. Interesting indeed.
-Eric
Everything is noctier in Sweden. 
djm
You just think it is. Relax and lucent your clothing.
djm
Beautiful! But I haven´t seen them. What´s so special about these clouds? The look pretty much like ordinary clouds to me.
http://en.wikipedia.org/wiki/Noctilucent_clouds
They are the highest clouds in the Earth’s atmosphere, located in the mesosphere at altitudes of around 85 km, and are visible only when illuminated by sunlight from below the horizon while the ground and lower layers of the atmosphere are in the Earth’s shadow; otherwise they are too faint to be seen. Noctilucent clouds are a not fully understood meteorological phenomenon. Clouds generally are not able to reach such high altitudes, especially under such thin air pressures.