Why blue is the rarest color in nature - Arnav Bhardwaj
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A glance at the sky or ocean may leave you thinking blue is the most common color in nature. But here’s a quick fact for you to chew on: neither the sky nor the ocean is truly blue!
NASA explains: “The reason the ocean is blue is due to the absorption and scattering of light.” In oceans, the longer wavelengths (like red, yellow, and green) are absorbed into the water. Then, just like the sky, particles scatter the shorter wavelengths (blue and violet) much more, and thus they hit our eyes more. It boils down to a principle called Raleigh Scattering, which states that particles can scatter light. A subsection of this principle explains that shorter wavelengths are scattered more than long wavelengths.
Let’s take a look at the color blue in animals. We know that some birds and fish appear blue, but most notably: butterflies. But blue animals’ colors don’t come from a pigment, but rather: physics. Upon close inspection of a butterfly wing, we see intricate, layered, scale-like ‘nanostructures’. They help manipulate the light, bending and reflecting it, canceling other wavelengths out - until only the color blue is left. This is exactly what happens on the feathers of blue jays, on the scales of fish, and the flashing rings in octopi. Mammals, who normally have fur, aren’t able to create the same kind of effects, thus the rarity of them in the wild.
The scarcity of blue has affected the world for thousands of years. In Medieval Europe, the ink ultramarine (ground from a rare stone) was as rare and precious as gold, used for decorating sacred texts. Blue has long been associated with the Hindu deity, Krishna, and with the Christian Virgin Mary. Artists were also inspired by blues, artists like Michaelangelo, Van Gogh, and Picasso! Its rarity fueled our curiosity.
Humankind’s eyes were always turned towards the unknown. The vastness of the sky, the ocean; the rarity of the color blue in the wild - it was all so different, so exotic. Perhaps that’s why blue, of the tens of hundreds of other colors, is the most popular in the world!
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