A striking circular formation captured in the sky above Phoenix has drawn widespread attention after images were shared by the weather-focused platform Meteo Balkans.

The unusual sight, described by meteorologists as a “Falling Streak Hole,” appeared as a large, round opening in an otherwise uniform cloud layer. While some social media users quickly joked about extraterrestrials, experts say the phenomenon has a well-understood scientific explanation.

A Falling Streak Hole — sometimes referred to as a perforated cloud — typically forms in mid- to high-level cloud layers such as altocumulus. These clouds often contain tiny water droplets that remain in liquid form despite temperatures below freezing, a state known as supercooling.

Under normal conditions, these droplets can remain unfrozen for extended periods. However, when ice crystals are introduced into the cloud layer, the supercooled droplets rapidly freeze. This process can be triggered naturally or by external disturbances such as aircraft passing through the cloud deck.

“When ice crystals are introduced, they act as a catalyst,” explained a meteorologist familiar with the phenomenon. “The surrounding droplets freeze, grow heavier, and begin to fall. As they descend, they leave behind a visible gap in the cloud layer.”

Once initiated, the freezing process can spread outward. As more droplets crystallize and fall, the hole expands, creating the dramatic circular or elliptical opening visible from the ground.

Photographs from Phoenix show a distinct round void surrounded by a thin cloud ring, a classic signature of the phenomenon. In some cases, streaks of falling ice crystals — known as virga — can be seen trailing beneath the opening.

Despite the scientific explanation, the images prompted lighthearted speculation online. Comments under the social media post ranged from humorous references to science fiction to playful suggestions about experimental technology. One user joked about “a portal to another dimension,” while another referenced mythical realms.

Meteorologists note that such reactions are common when rare atmospheric visuals appear. “Anytime something looks unusual in the sky, people’s imaginations take off,” one weather observer said. “But these formations are documented and have been studied for decades.”

Falling Streak Holes have been observed in various parts of the world and are considered uncommon but not extraordinary. Advances in photography and social media sharing have simply made them more visible to the public.

Experts emphasize that the Phoenix formation fits well within known meteorological patterns and does not indicate any unusual atmospheric danger.

As interest continues online, weather specialists encourage the public to appreciate the phenomenon as an example of the dynamic and complex processes occurring in Earth’s atmosphere.

While the images may appear mysterious at first glance, science offers a clear and grounded explanation — a reminder that nature itself can create some of the most dramatic spectacles in the sky.