A perfectly round circle was seen around the sun on Thursday and caused quite a stir on social media. Picture: Danie van der Lith
SOCIAL media was abuzz on Thursday when a large ring was spotted around the sun.
Pictures of this phenomenon flooded Facebook and other social media sites, where a lot of people wanted to know what it was and how it was created. My first thought was that Eskom was busy load-shedding the sun, but there is a scientific answer to the phenomenon.
They are known as 22-degree halos by scientists. They get their name from the fact that the radius of the circle around the sun or moon is approximately 22 degrees.
The traditional adage “ring around the moon” indicates impending precipitation. This adage is accurate since storms frequently precede towering cirrus clouds. Observe how the sky appears to be mostly clear in this picture. You can still see the sun and moon, after all. Halos, however, are an indication of high, thin cirrus clouds floating at least 20,000 feet (6 kilometres) above our heads.
The ice crystals in these clouds number in the millions. Both refraction, or the splitting of light, and reflection, or the glints of light off these ice crystals, result in the halos you observe.
For the halo to emerge, the crystals must be positioned and oriented precisely in relation to your eye.
Because of this, halos surrounding the sun or moon are subjective, much like rainbows. Each person sees their own unique halo, which is created by unique ice crystals that are distinct from the ice crystals creating the halo of the person next to you.