Leave a comment! Enter your keywords. Sign-Up Here. Ada McVean B. General Science. AdaMcVean Leave a comment! Is it true that the Beatles wrote a song about LSD? Is it true that you cannot eat polar bear liver? This type of scattering increases as the wavelength of light decreases, so blue light is scattered more than red light by the tiny air molecules in our atmosphere. At noon, when the Sun is overhead it appears white. Hence the Sun and skies look redder at dawn and dusk.
The low density of air molecules means that the Rayleigh scattering that causes our skies to be blue on Earth has a very small effect on Mars.
We might expect it to have a very faint blue coloured sky, but due to the haze of dust that remains suspended in the air the daytime sky on Mars appears more yellow.
This is because the larger dust particles absorb the short wavelength blue light, and scatter the remaining colours to give a butterscotch hue over the Martian sky. When the air is too thin for gas molecules to collide with each other, we call it an 'exosphere' instead. But what makes the sea blue — is it reflecting the blue of the sky? Water molecules are good at absorbing longer wavelengths of light, so when sunlight hits the water the reds and oranges get absorbed.
The shorter wavelength blue light is absorbed very little and much of it is reflected back to our eyes. This article has been written by an astronomer at the Royal Observatory, Greenwich. Written and illustrated by astronomical experts, Storm Dunlop and Wil Tirion, and approved by the astronomers of Royal Observatory Greenwich Buy Now. The sunlight reaching us from low in the sky has passed through even more air than the sunlight reaching us from overhead.
As the sunlight has passed through all this air, the air molecules have scattered and re scattered the blue light many times in many directions. Also, the surface of Earth has reflected and scattered the light. All this scattering mixes the colors together again so we see more white and less 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.
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