News
Ring around the sun a marvel if not a miracle
Nobody knows who spotted it first but news of an iridescent ring around the sun spread faster than light on Thursday, prompting crowds to look up at the sky. There was, in fact, a large circle of light resembling a full rainbow around the sun against the backdrop of a clear sky.
Solar Halo observed in Matara. Pic by Bhagya Malalgoda
The phenomenon was clearly visible in southern Sri Lanka, and it seems some people believed its sudden appearance in the sky to be a miracle linked to their religious or political beliefs.
Not so, said Professor Chandana Jayaratne, Head of the Department of Physics at the University of Colombo. It was not a miracle but a natural optical phenomenon called a “22-degree halo” caused by the refraction of the sun’s light by millions of hexagonal ice crystals in high-altitude clouds.
Because the radius of the circle around the sun or moon is approximately 22 degrees, this is scientifically termed a 22-degree halo, Prof. Jayaratne said.
The same conditions can cause “moon rings”’ often on full moon days but solar halos can be more colourful as the sun is brighter.
The halo’s inner rim was sharper than the outer, which looks more diffused, observers said, adding that the halo was reddish on the inside and bluer on the outer rim.
According to experts, this is not a rare phenomenon and is much more common than a rainbow but people generally missed it, not tending to look up into a sunny sky.
Lunar halos or moon rings on a full moon day were gorgeous to watch but people should be cautious if they want to observe a solar halo, the experts cautioned.
“Looking at the sun directly on sun can cause burns in the eyes resulting in permanently impaired vision,” Dr. Priyanga Iddawela, an eye surgeon at Matara Hospital, warned.