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<\/a><\/p>\nMaybe it is best not to try to analyze one of nature’s magical wonders as a rainbow too much (care to vote for your favorite water body?), as even the concept of the rainbow being a bow (arc) is not entirely true. Did you know that if the horizon wasn’t in the way, a rainbow would take the shape of a circle (as seen from an airplane, as in the picture below)?<\/p>\n
<\/p>\n Sun dogs<\/strong><\/p>\n Does this picture look familiar? It shows a parhelion, more commonly known as a “sun dog”. Oddly, I have seen these but never knew the official name until researching this article. In fact, sun dogs are a lot more common than rainbows. They are formed by light refracting through the ice crystals of cirriform clouds.<\/p>\n The most common parhelia are seen about 22\u00b0 on either side of the sun; they are created by falling ice crystals in the Earth’s atmosphere. As water freezes in the atmosphere, small, flat, six-sided, ice crystals might be formed. As these crystals flutter to the ground, much time is spent with their faces flat, parallel to the ground.<\/p>\n Why all the color?<\/strong><\/p>\n Probably in school you did an experiment where the teacher shines a white light through a glass triangle\u2014a prism, as in the left-side picture. The white light emerges from the prism split up into individual beams of different colors. The colors coming out of the prism, and in the rainbow, too, thus come from light, sunlight in the rainbow’s case. Sunlight is white light, but white light actually contains all of the colors of the rainbow all ready for you to see, but blended together. Light has wavelengths (don’t ask me what this means!) and each color of light has a different wavelength. When the light enters the glass, which is denser than air, it slows down and is bent, with the different wavelengths that make up white light bending at different angles (red on one side to violet on the other).<\/p>\n A similar situation happens in a raindrop, as the right side picture shows. The water drop is acting like a prism, except the light is being refracted at three different points (some of the light bounces off the back of the raindrop and back out to you as you watch). Each time the light beam bounces, it gets wider, and the rainbow you see is a combination of millions of these light beams coming back to you.<\/p>\n \u266b Somewhere over the raincircle \u266c … In daily life you don’t see rainbows very often, as three things have to come together:<\/p>\n The brightest rainbows appear when the water drops in the sky are large, so if a big rainstorm is moving off in front of you, the rainbows will be more spectacular. The lower the sun is to the horizon the more arc you will see. And, if you could float upwards, the higher you got the more circular the rainbow would become, especially if the sun is directly behind you. Circular rainbows are seen all the time\u2014not by floating people but by passengers flying in airplanes.<\/p>\n Multiple rainbows\u2014a rarity<\/strong><\/p>\n Have you ever seen six rainbows at once? They are not only rare to see — they are a puzzle to understand. The common rainbow is caused by sunlight internally reflected by the backs of falling raindrops, while also being refracted at the air\/water boundary. The sunlight in this picture is coming from behind the observer, and the rainbows are in the rainstorm. The brightest rainbow is the primary rainbow.<\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n
\n<\/strong>just doesn’t sound right<\/strong><\/p>\n\n