Beyond rainbows: The kaleidoscope that the sky has in store for us

“Magic exists. Who can doubt it, when there are rainbows and wildflowers, the music of the wind and the silence of the stars?”   

Well, these lines by famous American author Nora Roberts will resonate with most of you who've grown up watching rainbows, and fallen in love with them. Inadvertently. But the sky has a lot more in store to mesmerise us with, apart from rainbows. Yes, there are unique and spectacular kaleidoscopic occurrences that take place in the blue heaven. Here’s a glimpse of a few of them for you.    

Iridescent clouds 
Picture this: A disjunct cloud laced by a multi-coloured halo, which looks more like a mural rather than a celestial wonder. If you have ever spotted this scene, then you have probably come across iridescent clouds. They are also known as fire rainbows or rainbow clouds. But, what’s the secret behind this heavenly sight? Well, it’s pretty simple.    

Rainbow clouds form on top of cumulus clouds, the cauliflower-shaped fluffy cotton balls that reside at a height of about 1000 feet from the ground. This is what happens: Cumulus clouds push the air layers above them further upwards. This leads to the cooling and expansion of the air. Sometimes, tiny droplets form in this air when its moisture condenses suddenly. What results out of this whole process is a cap cloud. Known in the science fraternity as pileus, this cap is the secret behind the heavenly sight known as rainbow clouds. Usually, they accompany thunderstorms and appear in the late afternoon, on hot, humid days.  

Sun dogs 
Wait, you don’t have to be afraid of them. They don’t bite. Well then, what are sun dogs? They are a stupendously beautiful natural phenomenon occurring in the sky on winter afternoons or just before sunset during the sultry summer days. They look like a beaming circle around the sun. If you are fortunate enough, you may someday catch a glimpse of triple sun in the sky. This is also how sun dogs look, at times. Let us tell you how they actually form.  

There is ice up in the sky. Yes, it’s true. Clouds that drift vertically at the lower levels of air have ice crystals suspended in them. These are flat, hexagonal in shape and act as prisms that refract sun rays. As these ice crystals push vertically down the air, they refract sunrays horizontally. The rays penetrating an ice crystal pass from one side to another at a 60-degree angle and deviate at an angle of 22 degrees. This results in the formation of the heavenly halo that is known as sun dog.  Typically, a sun dog has a red inner edge and the outer edge has shades of orange fading into blue. Finally, all these colours coalesce into one another resulting in varying shades of white.  

Wondering how sun dog got its name? There is no definitive answer to this. One school of thought believes it to have its origin in the Greek mythology. According to legend, the ‘false suns’ around the sun, that we call sun dogs, were the dogs of Greek God Zeus who used to walk them across the sky.