The Sun's Halo was spotted again on Wednesday in parts of Hyderabad, days after people living in India's tech hub witnessed a rare phenomenon in skies over Bengaluru. The rainbow-coloured rings appeared encircling the Sun in the morning hours of Wednesday, brightened up the day.
The optical phenomenon is a result of ice crystals present in the atmosphere that appears covering the sun when refracted by sunlight. The rare occurrence takes place due to the dispersion of light. The phenomenon seen in Hyderabad and Bengaluru is not the first as similar rings were spotted in Tamil Nadu's Rameswaram last year as well.
What is Sun halo
Also known as '22 degree halo', it is an optical phenomenon that occurs due to sunlight refracting in millions of hexagonal ice crystals suspended in the atmosphere.
It takes the form of a rainbow-coloured ring with a radius of approximately 22 degrees around the sun or the moon.
Circular halos specifically are produced by cirrus clouds, which are thin, detached, hair-like clouds.
These clouds are formed very high up in the atmosphere, at a height of over 20,000 feet.
How Sun halo is formed
Clouds contain millions of ice crystals which refract, split, and even reflect the light to give an impression of a circular rainbow ring.
Sunlight through the ice crystals causes the light to split, or be refracted. When at just the right angle, it causes us to see the halo.
During the process, light undergoes two different refractions once when it passes through ice crystals and the second when it exists.
It bends depending on the diameter of the ice crystal and the two refractions bend it by 22 degrees from its original point giving it the name of a 22-degree ring.
They often do indicate that rain will fall within the next 24 hours since the cirrostratus clouds that cause them can signify an approaching frontal system.
