Mysterious light pillar hovers over Jeju Island

A series of light pillars hanging in the air for more than an hour on Jeju Island is the result of a rare optical phenomenon .

A pillar of light hovers in the sky in Jeju. (Photo: Newsweek).

Cylindrical pillars of light hovering in the sky above Jeju City in South Korea were captured by local residents and shared on social media, Newsweek reported on October 31. According to witnesses, the pillar of light appeared in the air for more than an hour. Many social media users thought it was aliens, but Alex O'Brien, a meteorologist for KOAA News5 in Colorado Springs, said it was an atmospheric optical phenomenon.

"Light pillars are an optical phenomenon in which light is projected from the ground into the sky, occurring when tiny ice crystals with an average size of about 0.02 mm form and float near the Earth's surface. They act as reflectors, transmitting the city's light back to the human eye or camera lens. Typically, the ice crystals are disc-shaped, forming at temperatures between -10 and -40 degrees Celsius ," O'Brien said.

The phenomenon has been recorded in the United States, but is rare in temperate regions like South Korea. On the night the photo was taken, the temperature did not drop below 12 degrees Celsius. However, the relative humidity was high, at around 72%, and there was very little wind. Those conditions are likely to promote the formation of light pillars . "From my experience living in Colorado, light pillars can appear once or twice a winter. The colder the night, the higher the chance of seeing a light pillar , " O'Brien shared.

Depending on weather conditions, the light pillar can last for hours, or even all night if the weather stays the same. To see the pillar, observers need to be outside during the coldest and dampest part of the night, and close enough to a city for the lights to reflect off, according to O'Brien.