The color of the sky has always intrigued humanity, but do you know how it gets its unique hues?
Cloud tones often indicate the state of the sky, and some people even used them to obtain information and interpret phenomena. For example, the Inuit look at the coloration of clouds to know where there is no frozen water so they can navigate during the Arctic thaw. In fact, their shades can help us interpret the weather, such as when they are gray and we know it will rain, or when the light comes from the reflection of the sea, their colors turn blue. But when twilight occurs, the clouds turn orange, so why exactly does this happen?
Light deviates as it enters the atmosphere.
The first thing to understand is that photons make their way through gas molecules in the atmosphere to pass through it, which becomes more complicated the denser it is, thus generating several consequences.
First, a part of the light is dissipated in the form of heat, this is known as absorption. And secondly, another part will be redirected in secondary waves, this is as if we throw a stream of water against a wall, diverting into different drops and jets, the same happens with light but millions of times along different trajectories through the atmosphere.
This is because each molecule and atom it passes through has a different ability to absorb and scatter light, so it will pass through at different wavelengths. For example, ozone is the gas responsible for protecting us from solar radiation by stopping ultraviolet light wavelengths, but it is not capable of filtering yellow light.
Orange clouds and Rayleigh scattering
There is a phenomenon that explains why the sky takes on orange tones, it is known as Rayleigh scattering, which occurs when a ray of light is scattered by particles smaller than its wavelength, depending on the size of this is that it will be its way of scattering light.
The white light coming from the sun is composed of a mixture of colors, and each of them has a different ease of passing through the atmosphere. During sunrise or sunset, the sun’s rays pass through a long stretch of the densest atmosphere, this is the closest to the ground, and therefore, its path is longer, so the probability that the sunlight is scattered even before it touches the ground or clouds is high. This is why first the color mixture is filled with yellow tones and as it disperses, orange tones will predominate.
There is another phenomenon that explains why clouds take on orange tones, it is known as Mie scattering and occurs when the scattering particles are larger or equal to the wavelength of the light and occurs when there are small water droplets suspended in the atmosphere.
The orange horizon is due to the effects created by the sun’s rays when they enter the atmosphere since this phenomenon does not distinguish between the wavelengths of the colors but disperses them all equally and so the clouds reflect only the color that reaches them if the light is white the clouds will look white, and if the light is orange they will look orange.
Story originally published in Spanish in EcoosferaPodría interesarte