A visual treat awaited people of Coimbatore, Nilgiris and other parts of western Tamil Nadu up in the skies as a giant halo formed around the sun on Friday morning.
The beautiful celestial halo, colloquially called as a ‘castle built by sun’ is a rare event that occurs when water crystals are present in the clouds. Scientists at Birla Planetarium say the rare event experienced in a high-altitude area in the state is a normal one as like rainbow and doesn’t hold any great significance.
“Whenever there is higher moisture content in the atmosphere and when sunlights falls on it, a circular ring is formed around the sun and we call it sun halo,” said Dr P. Iyamperumal, executive director, Tamil Nadu Science and Technology Centre (TNSTC).
He added that the
higher moisture content in the atmosphere naturally indicates rain that would be followed by rainbow.
TNSTC joint director-planetarium Dr S. Soundararajaperumal further said the sunlight refracts through the ice crystals present in the clouds at a 22-degree angle prompting scientists to call the event itself as 22-degree halo.
“The inner circle of the ring will be red in colour while the outer surface will look bluish,” he added.
He added that in the olden days, people took it casually, while today, the students are curious to know more about it.
While people in Coimbatore enjoyed the interesting spectacle on Friday, similar events occur across the globe whenever there is higher moisture content in the atmosphere. “We see such halo often around the moon and it is called moon halo,” said Dr
Iyamperumal.