Explain why is the sky blue

As the Sun gets lower in the sky, its light is passing through more of the atmosphere to reach you. Even more of the blue light is scattered, allowing the reds and yellows to pass straight through to your eyes.

Sometimes the whole western sky seems to glow. The sky appears red because small particles of dust, pollution, or other aerosols also scatter blue light, leaving more purely red and yellow light to go through the atmosphere. For example, Mars has a very thin atmosphere made mostly of carbon dioxide and filled with fine dust particles.

During the daytime, the Martian sky takes on an orange or reddish color. But as the Sun sets, the sky around the Sun begins to take on a blue-gray tone. The top image shows the orange-colored Martian sky during the daytime and the bottom image shows the blue-tinted sky at sunset.

Our World: Sunsets and Atmospheres. Why Is the Sky Blue? The Short Answer:. Blue light is scattered more than the other colors because it travels as shorter, smaller waves. Explore some more! When the air is clear the sunset will appear yellow, because the light from the sun has passed a long distance through air and some of the blue light has been scattered away. If the air is polluted with small particles, natural or otherwise, the sunset will be more red.

Sunsets over the sea may also be orange, due to salt particles in the air, which are effective Tyndall scatterers. The sky around the sun is seen reddened, as well as the light coming directly from the sun. This is because all light is scattered relatively well through small angles—but blue light is then more likely to be scattered twice or more over the greater distances, leaving the yellow, red and orange colours. A blue haze over the mountains of Les Vosges in France. Clouds and dust haze appear white because they consist of particles larger than the wavelengths of light, which scatter all wavelengths equally Mie scattering.

But sometimes there might be other particles in the air that are much smaller. Some mountainous regions are famous for their blue haze. Aerosols of terpenes from the vegetation react with ozone in the atmosphere to form small particles about nm across, and these particles scatter the blue light.

A forest fire or volcanic eruption may occasionally fill the atmosphere with fine particles of — nm across, being the right size to scatter red light. This gives the opposite to the usual Tyndall effect, and may cause the moon to have a blue tinge since the red light has been scattered out. This is a very rare phenomenon, occurring literally once in a blue moon. The Tyndall effect is responsible for some other blue colorations in nature: such as blue eyes, the opalescence of some gem stones, and the colour in the blue jay's wing.

The colours can vary according to the size of the scattering particles. When a fluid is near its critical temperature and pressure, tiny density fluctuations are responsible for a blue coloration known as critical opalescence. People have also copied these natural effects by making ornamental glasses impregnated with particles, to give the glass a blue sheen. But not all blue colouring in nature is caused by scattering. Light under the sea is blue because water absorbs longer wavelength of light through distances over about 20 metres.

When viewed from the beach, the sea is also blue because it reflects the sky, of course. Some birds and butterflies get their blue colorations by diffraction effects.

The other wavelengths stick together as a group, and therefore remain white. They are still mixed together, unscattered by the atmosphere, so they still appear white. The scattered violet and blue light dominates the sky, making it appear blue. What happens to the violet? Some of the violet light is absorbed by the upper atmosphere.

Also, our eyes are not as sensitive to violet as they are to blue. Closer to the horizon, the sky fades to a lighter blue or white. The sunlight reaching us from the horizon has passed through even more air than the sunlight reaching us from overhead. The molecules of gas have rescattered the blue light in so many directions so many times that less blue light reaches us.

As the Sun gets lower in the sky, its light passes through more of the atmosphere to reach you. Even more of the blue and violet light is scattered, allowing the reds and yellows to pass straight through to your eyes without all that competition from the blues. Also, larger particles of dust, pollution, and water vapor in the atmosphere reflect and scatter more of the reds and yellows, sometimes making the whole western sky glow red.