What is the Colour of the Sky?
People generally know the sky is blue, yet few understand its fascinating science behind this optical effect. Color results from waves passing through an object being reflected, refracted or scattered back onto itself with some frequencies being absorbed while others pass right through.
Lord Rayleigh first noted that atmospheric particles scatter blue light more strongly than any other color.
Blue
The sky appears blue due to how sunlight travels through our atmosphere. Sunlight itself is white; as soon as it enters, however, it becomes scattered by various gases and particles in the air and gets scattered more than any other wavelength – blue light being most affected and thus contributing to its appearance in our skies.
Sky colors may also be altered by clouds and pollution that create a hazy appearance, as well as volcanoes or forest fires that create red or orange hues in the sky.
At first, blue-green microbes existed in the ocean that were capable of performing an extraordinary feat: turning sunlight and carbon dioxide into oxygen. Gradually, this natural process spread throughout all oceans and slowly added oxygen to our atmosphere – as oxygen levels rose, so too did its blue hue become more prominent.
Isaac Newton used a prism to demonstrate that sunlight contains all colors of the rainbow and that white light cannot be produced without scattering some of these hues. Later, Lord Rayleigh determined that blue skies result from air molecules (primarily nitrogen and oxygen ) scattering visible light around.
As solar radiation passes through Earth’s atmosphere, it is reflected off molecules of air, dust particles and water droplets and scattered to alter its direction of travel, altering its colour accordingly and giving dusk or dawn skylines their signature lighter hues of blue hues.
Refraction gives the sky its characteristic color through lightbending as it travels from mediums with higher densities (such as water) into ones with lower densities ( such as air). When light enters denser layers of air, its energy may be refracted in different directions and give off its characteristic hue – creating the characteristic hue associated with blue skies.
Green
Sometimes people may notice the sky turning greenish; this occurs as a result of several factors, particularly light interaction with clouds.
Air particles scatter violet and blue light more efficiently than red light; our eyes being more sensitive to blue. But when this blue scattered light comes against a background rich in red hues (such as during sunsets) or dark gray ones (such as clouds that harbor tornadoes), it may appear green.
Dense atmospheric layers alter how light is scattered by Rayleigh scattering. As Earth’s atmosphere thickens or densifies, its constituent molecules can bend or refract light traveling through it; causing distant objects like suns and moons to assume different hues as they approach lower in the sky.
Dust, smoke, pollen or pollution can have a significant effect on the colors of the sky, producing certain hues or tints when conditions are dry and smoggy.
Finding specific shades of green can be hard, but deep clouds during thunderstorms often reveal it. This is due to water droplets within clouds being adept at reflecting blue light while not fully absorbing it; when this greenish reflection meets with the fading sunlight during a storm it creates an eye-catching hue in the sky that gives off that distinct greenish tint – not an indication of impending tornado or hail damage, but instead likely caused by multiple factors rather than simply hail.
Yellow
Yellow skies can often signal severe thunderstorms that could bring tornadoes and hurricanes – so seeing one turn yellow should serve as a warning that bad weather is on its way. But, it is important to keep in mind that not all yellow sky appearances signal severe storms – there can be other reasons for why skies turn yellow as well.
Clouds are often responsible for turning the sky yellow, acting as a light filter and altering how sunlight displays itself; this causes blues and greens to appear darker while yellows and oranges lighten in hue.
Pollution or smoke is also one of the main culprits behind yellow skies. Pollution alters how sunlight scatters into the atmosphere, decreasing how much blue light from the sun is scattered and making its brightness less obvious. Smoke may have an equally negative impact on a sky as it blocks some blue wavelengths from being dispersed into space.
One reason the sky may appear yellow is a result of a duststorm or sandstorm. Recently, parts of Europe have been covered in an intense layer of Saharan dust from North Africa, and this has given it its characteristic yellow tint as the dust prevents any of the blue light from being scattered into space.
Remember, however, that skies come in all colors from red and orange to pink depending on Rayleigh scattering effects; certain wavelengths tend to be scattered more than others (for instance blue wavelengths from the sun are scattered more often than orange wavelengths resulting in blue skies).
Red
As the Sun rises and sets, its rays pass through Earth’s atmosphere, scattering and absorbing in varying amounts depending on wavelength; shorter wavelengths (such as blues and greens) tend to be scattered more than longer ones such as reds or yellows; this produces visible colors which make up what we view as “sky.”
It’s no coincidence that it tends to be blue during the day; the shorter wavelengths of blue light scatter more, giving us what we perceive to be sunlight. On the other hand, violet and red wavelengths do not scatter as strongly and therefore have less of an effect on its brightness than their blue counterpart.
The color of the sky can also change according to atmospheric conditions, typically appearing bluer when air quality is improved while being darker or paler during times of smog or pollution events.
Dust or smoke particles present in the air can also turn it red, creating dramatic sunsets that look even more breathtaking when seen from rural settings or oceanic or desertic regions compared to when occurring over cities or towns. This explains why some paintings by Turner or Edvard Munch can have red tones.
Colour of an object depends on many variables, including its frequency and polarity of light passing through, what its atoms absorb or reflect back, whether the object emits any light of its own, how our eye is designed and trained to recognize colors etc. While we all intuit that the sky is blue, its true answer involves much more complex Physics, Astronomy and neurological mechanisms at play! While we all intuitively know that its hue may be blue!
Orange
As the sun sinks lower in the sky, its hue turns orange and yellow due to light being refracted through our planet’s atmosphere, making objects further away appear squashed while changing their primary hues.
Air pollution such as dust, smoke and pollutants can alter the color of the sky by dispersing light that was once blue into an orange or brown hue, often caused by wildfires but also due to pollution like smog, factory emissions or human-made aerosols. This phenomenon can make light less blue while decreasing blueness by an average of four levels or so – often making light less blue but more orange or even brown in hue compared to before! This effect may also occur as part of wildfire smoke plume dispersion although can also result from air pollution such as smog, chemical emissions from factories or human-made aerosols emitting toxic fumes into the atmosphere resulting in hue changes ranging from less blue light being visible due to decreased bluelight emissions or human-made aerosol emissions or human-made aerosol emissions creating brown-toned skies as seen around wildfire smoke dispersion as well as human-made aerosol emissions creating brown-toned lighting effects resulting from firefighter smoke dispersion caused by smoke emissions from factories or human-made aerosol emissions from factories producing chemicals causing releases from factories emitting into human-made aerosols produced via factories producing chemicals then emissions via factories emitting chemicals into human-made aerosols produced aerosolized aerosol emissions produced during combustion processes taking place within their environments as human-made aerosol emissions occurring within its surrounding environment, as seen when fighting begins for example when surrounding wildfires take place as resultant conditions within their vicinity causing brown hued hued tones as seen when air quality become polluted or human made aerosol emissions of natural occurring due to air pollution due to human-made aerosols made aerosols from factory emissions or human-produced aerosols or human made aerosols being produced human made aerosols produced aerosols in factories or human made aerosols used causing chemical emissions or human made aerosols produced aerosols from which causes in them when fires do also changes could occur during fire-case by wildfires can vary by differentias may or caused from non-into start before burning started occurring due to make them when present due to humans pollu emissions v or manufactured aerosol emissions caused due chemical emissions to be present during firefighters being caused due to human-produced aerosols to which caused air.
As the sun moves closer to the horizon at sunrise and sunset, its light must travel through an increasingly thick layer of atmospheric gas, scattering itself across short wavelengths like blue and violet while longer ones such as red and orange can still shine through.
Dust storms or wildfires are another way to turn the sky orange. Dust particles in the air scatter blue light while also letting in more orange wavelengths; creating an eye-catching orange skyscape.
Orange can be an extremely beautiful hue when combined with other hues. Vincent van Gogh and Pierre-Auguste Renoir used orange in combination with blue often in their work; both knew blue and orange complement each other well as complementary colors that help each other stand out more. When you next see an orange sky overhead, take a moment to appreciate its beauty before it slips away; sunset and sunrise skyscapes with vivid orange skies are precious opportunities that shouldn’t be wasted.