The sky is in charge of giving us the greatest phenomena, in the darkness of the night we can observe in its vault the movements of the stars and the brilliant meteor showers. But during the day, visual spectacles capable of astonishing anyone who allows themselves to look up also parade through it. Although a serendipity must occur to look at some of them, such as the mysterious iridescent clouds that stain the sky with colors with their visual poetry.
From time to time rainbows can appear in the sky, without a doubt we are used to them. But it can also happen that vaporous clouds seem to intermingle with brushstrokes of colors, as if they themselves were transformed into rainbows. They are known as iridescent clouds and result from a beautiful optical phenomenon.
What are iridescent clouds and why do they occur?
The iridescent clouds are a rare phenomenonTherefore, when they make their appearance, they quickly become relevant among lovers of natural beauty. But there is an explanation behind this strange and ineffable natural phenomenon. The iridescence of the clouds appears as a result of diffraction of sunlight through small water droplets, or even small crystals that make up the clouds. When the sun’s rays pass through the small droplets, the light is bent individually.
And although its iridescence can immediately take us back to a rainbow, it should be noted that it is not the same phenomenon that causes them. The rainbow appears thanks to refraction of light that breaks down into a visible spectrum, which is why we always see the same seven colors in this phenomenon. Instead, iridescent clouds are more like what happens in puddles of water when you spill oil or gasoline.
refraction and diffraction
When we talk about refraction, we mean the dispersion of light. But when we talk about diffraction, it refers rather to the deviation of the sun’s rays. For this reason, iridescent clouds usually appear in cloud formations that have a short life time, since the drops are usually very small and have a better opportunity to act as a new emitter that will deform the rays that pass through it. In other words, diffraction occurs when light passes through such a tiny obstacle (drops) that it manages to distort the light waves. The result is a pattern of iridescent spots in the sky, usually behind clouds.
But when talking about nature, situations cannot be deterministic, so different types of iridescent clouds have appeared in the heights. Many of them look pearly, while others look more like a rainbow. However it may be, all of them are extremely beautiful and exquisite to observe.
Credits: Göran Strand
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