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Few things in nature are as instantly recognizable as a rainbow. For thousands of years, rainbows have inspired myths, religion, art and science. Yet behind those bands of color is an extraordinary interaction between sunlight, water, geometry and the physics of light itself. From double rainbows to circular rainbows seen from aircraft, the science behind them is far more fascinating than most people realize. Learn more about rainbows and how they work on this episode of Everything Everywhere Daily. This episode is sponsored by Newspapers.com as a history buff, you know that while textbooks record the dates of our nation's conflicts, they often lose the voices of the individuals who served. This Memorial Day as we honor those who made the ultimate sacrifice, Newspapers.com invites you to go beyond the monument and discover the personal stories of the people we remember. Think of it as a bridge to the past, giving you access to over a billion pages of primary source history. This is your chance to move past the generalities of war and find the specific local heartbeat of that era. Newspapers.com provides a vibrant, unfiltered view of the past, letting you see the nuance, the sacrifice, and the everyday lives that shape the world that we live in today. It's more than an archive, it's a way to ensure these stories are never forgotten. This Memorial Day. Give a voice to the names in your family tree. Visit newspapers.com today and use promo code everything everywhere at checkout for 20% off your subscription. Newspapers.com honor the past by uncovering its stories. This episode is sponsored by Quince. I recently moved into a new, larger place and I faced the challenge of decorating it. I of course am turning to Quince to help get the job done. In addition to clothes, Quince offers stylish home furnishings that makes my place look great at affordable prices. And I've also recently picked up a second cashmere sweater that I've talked about before just because I like it so much. The great thing about Quince is that their prices are 50 to 60% lower than those of similar brands. How Quint's works directly with ethical factories and cuts out the middleman so you're paying for quality, not brand markup. Everything is designed to last and makes getting dressed and decorating your home easy. Refresh your everyday with luxury you'll actually use. Head to quince.com daily for free shipping on your order and 365 day returns. Now available in Canada too. That's Q U I-N-E.com daily for free shipping and 365 day returns. Quince.com daily. Rainbows are one of the most beautiful phenomena in nature. They can be seen after a rain shower, Near a waterfall, or even if you're spraying water from a hose. While everyone is familiar with what a rainbow is and what they look like, Most people have no clue how they're formed or why they exist. A rainbow is formed when sunlight enters Many tiny water droplets in the air and is bent, separated into colors, reflected and bent again before reaching your eye. The key physical processes involved Are refraction, dispersion, and internal reflection. Sunlight looks white, but it's actually made up of many different wavelengths of light. Red light has a longer wavelength. Violet light has a shorter wavelength. And the other visible colors all fall between them. When sunlight passes from air into water, it slows down. Because light travels more slowly in water than in air. This change in speed causes the light to bend. That bending is called refraction. The amount of bending depends on the wavelength of the light. Violet light bends slightly more than blue, blue more than green, green more than yellow, and red bends the least. This separation of white light into colors Is called dispersion. It's the same basic effect When a prism splits sunlight into a spectrum. Inside a raindrop, sunlight enters near the front surface of the drop. As it crosses from air into water, the light bends towards something called the normal, Meaning towards an imaginary line Perpendicular to the surface of the water drop. The separated colors then travel through the droplet and strike the back inner surface of the drop. Some of the light passes out of the drop, but some reflects off the inside of the droplet and travels back towards the front. When the reflected light exits the droplet, it returns to the air from the water. Since it speeds up when it leaves the water, it bends once again, this time away from the normal. The second refraction spreads the colors even further apart. The important angle for a primary Rainbow is about 42 degrees. More precisely, red light emerges from the raindrop at about 42 degrees from the opposite direction of the sun, While violet light emerges at about 40 degrees. That is why red appears on the outer edge of a rainbow and violet on the inner edge. The other colors fall between those angles. You see a rainbow only when the sun is behind you and the rain or mist is in front of you. The center of the rainbow lies on a line Extending from the sun through your head and eyeball to the opposite point in the sky, Called the antisolar point. Every droplet that sends red light to your eye at roughly 42 degrees contributes to the red band. Droplets sending violet light at roughly 40 degrees contribute to the violet band. Millions of droplets are doing this all at once, and your eye sees their combined light as a colored arc. A rainbow is actually part of a circle, not a true arch. The circular shape happens because all the droplets sending light to your eye at the correct angle form a cone around the antisolar point from the ground. The lower part of the circle is usually blocked by the horizon. From an airplane or a mountain, it's sometimes possible to see a nearly full circular rainbow. Double rainbows happen when the light reflects twice inside the raindrop before exiting. The second reflection sends light out at a different angle, around 51 to 54 degrees from the antisolar point. Because of the extra reflection, secondary rainbows are dimmer and wider with the color order reversed. Red on the inside and violet on the outside. While rainbows show the full spectrum of visible light, they're not the only natural phenomenon to do so. There are other ways it can happen as well. One of the most common is a halo around the sun or Moon. These halos are created by ice crystals high in the atmosphere, usually in cirrus clouds. The crystals refract light in a way similar to water droplets, or often creating a pale ring about 22 degrees around the sun. Sometimes the edges show distinct reddish and bluish colors. Sun dogs, also known as perihelia, are bright colored spots that appear on either side of the Sun. They're also caused by ice crystals, but specifically by hexagonal crystals aligned horizontally in the atmosphere. Sun dogs often display rainbow like colors, especially red nearest the sun and blue farther away. Cloud iridescence occurs when sunlight passes through very small water droplets or ice crystals. In thin clouds, the light diffracts around particles, producing pastel bands of pink, green, blue and yellow. The effect can sometimes resemble oil when it's floating on water. Glories are colorful rings sometimes seen around the shadow of an airplane, on clouds, or around a mountaintop shadow and fog. They are caused by backscattering and diffraction of light by tiny droplets. Unlike rainbows, glories form concentric circles centered on the observer's shadow. Not surprisingly, rainbows have been studied throughout history and have found places in the stories of various cultures. In the biblical story in the Book of Genesis, the rainbow is presented as a sign of God's covenant with Noah after the flood. It symbolizes the promise that the Earth would never again be destroyed by a global flood. Another example is of the ancient Greeks who had a goddess named Iris. Iris was the goddess of rainbows and the messenger for the Olympian gods. Iris was viewed as a Personification of rainbows, and it was believed that she was traveling on them when sending her messages. Her parents were a marine God and a cloud nymph, suggesting that the Greeks understood to some extent how rainbows functioned. Across Norse and Japanese mythology, the arched form of the rainbow led to its symbolization as a bridge. While these cultures interpreted the bridge differently, with the Japanese seeing it as a gateway to heaven and the Norse seeing it as a route between different realms, both utilized it to represent a physical link between the natural and supernatural worlds. In Hindu and Buddhist Tantra traditions, rainbows are seen as a physical manifestation of those who have achieved the highest possible meditative state. When a person reaches this state, they obtain a rainbow body. This is the state in which a person's body dissolves into light at death. In this case, they experience total liberation and become pure essence. This is considered to be the final step before nirvana, or the highest stage of enlightenment. In many indigenous Australian traditions, the Rainbow Serpent is a major spiritual figure associated with water, fertility, creation, and the shaping of the landscape. The Rainbow Serpent appears in numerous dreamtime stories across different aboriginal cultures. In Chinese mythology, the goddess Nuwa was said to repair the broken sky using stones of five colors, and rainbows were sometimes viewed as evidence of this repair. Nuwa is one of the most important crater figures in this Chinese tradition. Irish folklore contains perhaps the most famous legends regarding rainbows centered on both. Leprechaun These beings originate from the Celtic religion, which was a pre Christian polytheistic religion where divine entities were thought to derive their power directly from the natural world. Often portrayed as elderly tiny men who are expert craftsmen, leprechauns are said to belong to a race that lived in Ireland before humans arrived. They are frequently seen as personifications of nature and are famously known for possessing a concealed pot of gold. The treasure is supposedly hidden at the rainbow's end, fiercely guarded by these creatures. By choosing such a location, leprechauns demonstrate their wit. Because a rainbow's end can never actually be reached and the gold remains permanently inaccessible to humanity. According to legend, a leprechaun will only relinquish his wealth to someone capable of capturing him. Symbolically, the rainbow in the leprechaun story serves a lesson. Because the rainbow is nothing but an illusion, the treasure underneath it is unobtainable. It's a cautionary tale, essentially telling the audience that pursuing the treasure is impossible and that some dreams simply aren't meant to come true. The scientific study of rainbows also goes back thousands of years. One early philosopher who studied rainbows was Aristotle. This is particularly evident in his work Di Meteorologica. During his time studying rainbows, he speculated about how they formed, positing that the colors came from the sunlight reflected in raindrops. The next notable scientist to study rainbows was Theodoric of freyberg. In the 14th century, Theodoric was known for studying how rainbows form by using a globe of water. He viewed the globe as a representation of a raindrop. When a ray of light entered Theodoric's raindrop, It experienced a similar phenomenon to how water drops and light form rainbows in a natural setting. While his research was fundamental in improving the refracting process, the first full explanation of how rainbows work didn't occur until the 1630s. This was done by the French philosopher and scientist Rene Descartes. Descartes studied rainbows Using a boiling flask filled with water. He placed a screen with a hole in front of it. A white beam of light shone through the hole, mimicking a sunbeam. When the beam hit the water, A rainbow then appeared on the screen. Descartes further proved his experimental findings with mathematical evidence. Descartes showed that the light that passed through the raindrop was emitted in different directions, approximately 42 degrees from its origin. Each color refracted differently, so some appeared at different rainbow angles. Isaac Newton revolutionized the understanding of rainbows in the 17th century by showing that was white light is composed of many colors. Using a glass prism, he demonstrated that sunlight could be separated into a spectrum and then recombined back into white light. Newton realized that rainbows form because water droplets act like tiny prisms, refracting and separating sunlight into its component colors. His work helped replace earlier theories that held that colors were somehow created by the water or the atmosphere itself. During the 19th century, scientists developed the wave theory of light, which greatly improved the understanding of rainbows. Thomas Young showed that light behaves like a wave, helping explain interference and diffraction effects seen in phenomena such as rainbows. Rainbows are among the few natural phenomena that have inspired mythology, religion, art, and science. What appears to be a simple band of color in the sky is actually the result of geometry on optics, atmospheric conditions, and the fundamental nature of light itself. From ancient stories about divine bridges and serpents to Newton's prisms and modern physics, Rainbows have continually reminded us that even familiar things can contain extraordinary complexity. So the next time you see one after a storm, you'll know that there's far more happening than just sunlight and rain. The executive producer of Everything Everywhere daily is Charles Daniel. The associate producers are Austin Otkin and Cameron Kiefer. Research and writing for this episode was provided by Olivia Ashe. My big thanks go to everyone who supports the show over on Patreon. Your support helps make this podcast possible. And I also want to remind everyone about the community groups on Facebook and Discord. This is where everything happens that's outside of the show. As always, if you leave a review on any major podcast app or in the above community groups, you too can have it read in the show.