“UFO halo” appears in Romanian sky
People who filmed the phenomenon say viewed from a distance, and outlined by a ring of sunlight, the cloud looks like an alien aircraft.
But weather specialists say the formation, known as a "fallstreak hole", occurs when moisture in the air cools below zero Celsius but doesn't quite turn to ice.
The cloud in Romania appeared just weeks after a similarly striking formation appeared over Moscow.
Meteorologists explained that the phenomenon is an optical effect produced by rare weather conditions.