| The antarctic ice cap is a perfect archive for precpitation and dust particles. Even with a blue sky you findprecipitation of ice particles at Kohnen Station, which can build a halo. Besides the terrestrical dust also extraterrestrical dust is deposed. On top left an extraterrestrical dust particle in size of a few micrometer is included.
Foto: Johannes Freitag & Hubertus Fischer, Alfred Wegener Institute.