All-Sky NLCs

Imaged in Finland by Marko Mikkil� on the night of July, 31-1st August. ©Marko Mikkil�, shown with permission.

The bright noctilucent clouds extend from the northern horizon to well past the zenith.

The close-up below reveals their characteristic ribbed and skein-like structure.

The clouds, 80-85 km high (50-53 mile) high in the mesosphere, are composed of sub micron sized ice crystals. The clouds shine by scattering high altitude sunlight.