Another important thing to know about light is that it travels in a straight line unless something gets in the way to. The blue and violet waves, however, are just the right size to hit and bounce off of the molecules of gas in the atmosphere. This causes the blue and violet waves to be separated from the rest of the light and become scattered in every direction for all to see.
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. At sunset and sunrise, the angle at which sunlight enters the atmosphere is significantly changed, and most of the blue and green shorter wavelengths of light are scattered even before reaching the lower atmosphere, so we see more of the orange and red colours in the sky.
The ocean is not blue because it reflects the sky, though I believed that up until a few years ago. Water actually appears blue due to its absorption of red light. When light hits water, the water's molecules absorb some of the photons from the light.
Everything absorbs at a different wavelength Your green t-shirt absorbs red , and as a result reflects the remaining colours back at a viewer that's why your t-shirt looks green. In shallow bodies of water like a drinking glass light penetrates it completely, as there is not enough water to absorb enough photons, so we see the water as colourless. 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. Images sent back from the Viking Mars landers in and from Pathfinder in showed a red sky seen from the Martian surface.
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!
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