Noctilucent clouds over trees at twilight. Noctilucent clouds are very thin and form high above the Earth at heights of 75-90 kilometres. Because they are so thin and high, they can only be seen at twilight, shining in the glow of the setting Sun, and usually only at high and low latitudes. Photographed at 21:19 UTC on 14 July 2009, from southern Berkshire, UK. | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / STEPHEN BURT |
Taille de l’image : | 5120 px × 3414 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |