It looks like an irregular patch of color in the sky, as if a giant soap bubble were floating there,
researchers explained after spotting a rare optical display near the Akademik Vernadsky Antarctic station, according to Ukrinform.
Ukrainian polar researchers captured the iridescence of cirrus clouds in the sky above the research outpost. The National Antarctic Scientific Center detailed the sighting on Facebook, noting that the unusual shimmering colors emerge through complex light diffraction and interference.
The optical effect occurs when sunlight bends around tiny obstacles and passes behind them, after which the light waves overlap to create shimmering colors. In high-level cirrus clouds, these obstacles consist of microscopic ice crystals that form the majority of their structure, according to the National Antarctic Scientific Center reported by MENAFN.
These polar clouds typically reside at altitudes between 4 and 6 kilometers where temperatures drop to -20°C or lower. Because they are thin and transparent, the colorful play of light remains clearly visible against the Antarctic sky.
The appearance of the phenomenon depends directly on the size, shape, and distribution of the ice crystals within the cloud. The polar researchers noted that the colors always distribute unevenly, mirroring the specific contours of the cloud structure.
This irregular shape serves as the primary feature distinguishing iridescence from similar optical events like coronas and halos. While halos and coronas feature a clearly defined circular shape arranged symmetrically around a light source, iridescence follows no such geometric rules.
Polar researchers added that this optical display is more commonly observed in low- and mid-level clouds, though only along their outer edges. This occurs because lower clouds are generally opaque while maintaining transparent borders.
Separately, researchers near the Vernadsky station recently documented a record-early return of penguins to Galindez Island. The team registered a record October air temperature of +11.1°C near the station, the highest figure recorded throughout the observation period.
Sunlight bends around tiny ice crystals inside high-level cirrus clouds through diffraction, causing light waves to overlap and create shimmering colors.
Iridescence forms irregular patches following cloud contours, whereas halos and coronas display a distinct circular shape arranged symmetrically around the light source.
In polar regions, these high-level clouds reside at altitudes of 4 to 6 kilometers where temperatures reach -20°C or lower.
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