Sky colors vary throughout the day and evening due to gases present in our atmosphere that produce hues which reflect these particles, such as oxygen.
As sunlight enters our atmosphere, its energy is scattered by various molecules; blue light scatters more readily than any other color on the spectrum; thus giving our sky its distinct blue hue.
Light
As sunlight passes through Earth’s atmosphere, it gets scattered by gas molecules present. Light with shorter wavelengths (such as blue) tends to get scattered more easily than long-wavelength lights (such as red); this process is known as Rayleigh scattering and it explains why skies appear blue.
At midday, sunlight must pass through an expansive region of atmosphere before reaching our eyes, and blue light tends to scatter easily, while redder wavelengths reach us directly – thus giving rise to a sky that appears blue during daylight and reddish at sunset and sunrise.
Atmospheres comprised mostly of nitrogen and oxygen gases are exposed to sunlight and become vibrated, sending particles flying off in all directions; some of which reach your eye, whereupon your brain interprets these signals as colors that you see.
Scientists have long attempted to understand why the sky is blue for millennia. Aristotle may have first raised this question in his treatise On Colors; his suggestion being that its hue may result from air clarity close by. Roger Bacon and Kepler provided similar explanations in 13th-century.
Einstein realized in 1905 that the reason behind the sky’s blue hue lies within physical reality of atoms. When sunlight strikes molecules of our atmosphere, their electrons vibrate at frequencies similar to their natural resonant frequency causing vibrational movement that gives off blue light reradiated back out into space.
Blue wavelengths scatter more easily than other wavelengths and therefore have more intensity when reaching our eyes; this explains why our daytime observations of the Moon, planets, and stars appear bluer in intensity than their counterparts at nighttime due to a less dense atmosphere at night allowing more redder wavelengths of light through. As such, stars in the night sky appear redder while moon, Sun, and stars seem more whitish blue during daytime observations.
Atmosphere
When sunlight strikes the atmosphere of Earth, its light scatters in all directions. Wavelengths that contain blue wavelengths tend to scatter most readily – this is why our sky appears blue compared to red or orange which tend to pass more easily through.
The sky’s colors can change throughout the day and depending on weather conditions. At sunrise and sunset, for instance, sunlight must pass through more atmosphere – this means passing through gas molecules and dust particles which cause its hues to merge together; hence why sunrise/sunset brings paler hues closer to the horizon than during other parts of the day when overhead. This phenomenon explains why our view of the horizon appears paler nearer its limits while overhead, the sky appears more whiter.
Atmospheres consist of air and other gases like nitrogen and oxygen, acting like prisms to reflect certain wavelengths of light while absorbing others. Light that reaches Earth from the Sun comes with all colors of the rainbow; when passing through our atmosphere it gets reflected back as blue wavelengths instead.
Earth has the bluest sky of all planets due to the unique combination of gases present in its atmosphere; other planets contain different mixtures that would cause their skies to differ in hue; even the moon has different elements than Earth so its hue varies somewhat! We would like to thank Gotz Hoeppe from KSWO’s own Physics department for his expertise on this subject! He recently published Why the Sky is Blue: A History and Science book and takes readers on an entertaining historical and scientific journey from ancient mythology through modern physics! It makes the perfect present for any curious minds out there!
Oxygen
Humans strive to understand their environment. But oftentimes the answers to our queries can be more complex than anticipated; such is the case when discussing why our sky is blue; people have spent many years trying to decipher why this color exists, with mythical explanations and scientific theories proven incorrect over time providing different explanations.
Aristotle may have first raised this question in his treatise on Colors. Later scientists, such as Newton, Roger Bacon and Johannes Kepler all tried to answer it with their theories: they speculated that something in the air changed its light to make it appear blue – from oxygen inhalation refracting light through to atmospheric prism effects acting as prisms to even clouds creating blue skies!
Scientists began developing a more accurate theory in the 19th century, under John Tyndall and Lord Rayleigh’s direction. These scientists discovered that light is scattered by particles in the atmosphere, with shorter wavelengths such as blue being more likely to be scattered than longer ones (such as red).
When white light from the sun strikes gases in our atmosphere, it gets scattered by molecules composed primarily of nitrogen and oxygen, but there are also trace amounts of carbon dioxide and methane present. Because these gases are many thousands of times smaller than wavelengths of light, they scatter it and transform its color to various hues – mostly blue in hue.
Note that our sky is not simply composed of blue and white colors; rather, its composition consists of various hues that combine to form its signature white hue.
If you’re wondering why the sky is blue, one answer lies within how light reflects off objects in nature. For example, sunlight reflecting off of an ocean surface can make it appear blue; similarly, when sunlight reflects off ice crystals in the atmosphere it creates brilliant bursts of colored or white light that create beautiful halos around sun or moon.
Water
The sky is blue because water is an integral component of our atmosphere. Though invisible to our senses, its presence can be detected by cameras and satellites. Water vapor in the air is invisible to human eyes but visible by cameras and satellites – appearing grey near by and with blue hues further away due to light reflection from water molecules scattering light back in various directions, most prominently blue. Other lights pass through unabsorbent molecules instead, giving rise to blue-tinged skies during daytime hours but turning white at nightfall.
Long ago it was thought that something in the water refracted blue light and made it seem closer. Once scientists became better acquainted with atoms they realized it was actually gaseous particles in the air that changed colors of light we saw.
Aristotle first raised this question in his treatise On Colors, suggesting that blue hue is due to water vapor in the atmosphere; however, this theory was never widely accepted. By the 19th century there had been much discussion on this subject as well as many attempts made at recreating a sky in a bottle (such as described by Peter Pesic).
In 1911, it became widely understood that the color of the sky is determined by the length of its wavelengths when they hit air molecules, with shorter wavelengths such as violet and blue being absorbed while longer waves such as red, orange and yellow pass through unimpeded. This explains why sunrise and sunset appear redr – due to longer distances for Sun’s light to travel through our atmosphere before reaching you.
The color of our skies can be affected by many different factors – not only our ancestors’ beliefs and scientific theories but also climate change, our planet’s ozone layer composition, climate variability and atmospheric gases such as CO2. This book takes readers on an exciting journey from ancient myths and philosophy through cutting-edge optics and statistical physics before concluding by showing how beautiful blue skies play an essential part of life on planet Earth.