{"id":10114,"date":"2023-09-24T22:00:00","date_gmt":"2023-09-24T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=10114"},"modified":"2023-09-25T05:35:26","modified_gmt":"2023-09-25T05:35:26","slug":"why-so-blue-the-science-of-the-skys-colors","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/why-so-blue-the-science-of-the-skys-colors\/","title":{"rendered":"Why So Blue? The Science of the Sky’s Colors"},"content":{"rendered":"\n

Ask a child to draw a picture of their house, and they will likely show the following: a lovely, humble abode where they and their family live and take shelter, plus maybe a few pets here and there. Add to that some surrounding trees or a street their house stands next to. Add a rainbow behind the house for good measure.<\/p>\n\n\n

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“File:Lao child drawing of a waterfall.jpg<\/a>” by Khamkhoune at 11 years old (contact Basile Morin)<\/a> is licensed under CC BY-SA 4.0<\/a>.<\/figcaption><\/figure>\n<\/div>\n\n\n

However, the large swath of blue that covers the space on top of the house roof remains static. Yes, there may be some clouds here and there, plus maybe a few birds for good measure and scientific accuracy\u2014the blue remains constant, nevertheless.<\/p>\n\n\n\n

These young minds may have found the time to ask their older siblings or parents the question perhaps as old as our own species’ set of two eyes: “Why is the sky blue?<\/em>“<\/p>\n\n\n\n

Now, some of you may have found yourselves in this very situation and were forced to come up with your answer to satiate the burning curiosity sitting in the back of the child’s mind; no need to worry, though, as we are ready to address the question to get you prepared for the next family reunion.<\/p>\n\n\n

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“Blue sky 2<\/a>” by Fabio Marini<\/a> is licensed under CC BY 2.0<\/a>.<\/figcaption><\/figure>\n<\/div>\n\n\n

First Things First<\/h1>\n\n\n\n

Before anything else, there are a few things we need to consider, starting with a phenomenon called Rayleigh scattering<\/em>.<\/p>\n\n\n\n

Named after the British physicist John William Strutt, a 19th-century scientist perhaps better known for his title Lord Rayleigh, Rayleigh scattering occurs when sunlight interacts with the molecules and tiny particles in our planet’s atmosphere.<\/p>\n\n\n

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V0027060 Robert John Strutt, Lord Rayleigh. Photograph by Elliott & F\nCredit: Wellcome Library, London. Wellcome Images\nimages@wellcome.ac.uk\nhttp:\/\/wellcomeimages.org\nRobert John Strutt, Lord Rayleigh. Photograph by Elliott & Fry.\nPublished: – \n\nCopyrighted work available under Creative Commons Attribution only licence CC BY 4.0 http:\/\/creativecommons.org\/licenses\/by\/4.0\/<\/figcaption><\/figure>\n<\/div>\n\n\n

The thing is, sunlight isn’t just white light\u2014and you’d probably know about this once you learned how rainbows form.<\/p>\n\n\n\n

Light Up the Sky<\/h1>\n\n\n\n

Sunlight, as it turns out, is not just one color but a mixture of various colors that form what we perceive as white light. You’d see this whenever sunlight passes through a glass prism\u2014or perhaps a more naturally-occurring one in the form of millions of tiny water droplets, in the case of rainbows.<\/p>\n\n\n

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“File:Light dispersion of a mercury-vapor lamp with a flint glass prism IPNr\u00b00125.jpg<\/a>” by D-Kuru<\/a> is licensed under CC BY-SA 3.0<\/a>.<\/figcaption><\/figure>\n<\/div>\n\n\n

Now, light traverses through space in the form of electromagnetic (EM) waves (the whole wave-particle duality thing that light possesses), and visible light is classified within a particular “band” in the electromagnetic spectrum known as the visible spectrum<\/em>.<\/p>\n\n\n\n

What happens is that electromagnetic waves, and thus visible light waves, vary in energy, corresponding to the wavelengths they possess; generally speaking, less energetic waves travel with longer wavelengths, while more energetic ones travel with much shorter ones. (Scientists call this “inversely proportional.”)<\/p>\n\n\n

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“Visible spectrum 390-710 nm linear perceptual<\/a>” by Bhutajata<\/a> is licensed under CC BY-SA 4.0<\/a>.<\/figcaption><\/figure>\n<\/div>\n\n\n

In the visible spectrum, these wavelengths can be seen in the colors they emit; less energetic ones appear red, while more energetic ones appear blue, going towards violet.<\/p>\n\n\n\n

This is why the rainbow is arranged the way it is\u2014a prism (or, in this case, millions of water droplets) splits visible light into its component wavelengths, all with varying energies and thus colors. Hence, ROYGBIV. (Realistically, this should be more of ROYGCBV<\/em>; the colors between green and blue appear cyan, while indigo and violet are practically the same).<\/p>\n\n\n\n

This is also the reason why less energetic EM waves exist “below” red and outside the visible spectrum, hence why we only “feel” invisible infra<\/em>red (“below red”) radiation as heat. In the same vein, this is also why ultra<\/em>violet (“beyond violet”) radiation is so dangerous to our skin, despite being invisible all the same\u2014it’s more energetic than visible light and is thus “beyond” the visible spectrum.<\/p>\n\n\n\n

Back to the Sky<\/h1>\n\n\n\n
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