an a tenth as much as violet. Although violet light is scattered more than blue, our eyes are not very sensitive to violet and there tends to be more blue light in sunlight than violet. The blue predominates in our vision, so we see a blue sky. Red SunsetsSince the lower frequencies of light are scattered the least by nitrogen and oxygen molecules (the primary components of our atmosphere), red, orange, green, and yellow light are transmitted through the atmosphere much more than violet and blue. Red, which is scattered the least, passes through more atmosphere than any other color. Therefore, when white light passes through a thick atmosphere, the higher frequency blue and violet is scattered the most while the lower frequencies such as red are transmitted with minimal scattering. Such a thicker atmosphere is presented to sunlight at sunset, since the path through the atmosphere is longer as the sun is lower on the horizon. This means that the sun becomes progressively redder as the sun goes down, going from yellow to orange. As incoming sunlight passes through a denser atmosphere, shorter wavelengths of light (violet and blue) are efficiently scattered away by particles suspended in the atmosphere. This allows predominantly yellow and red wavelengths of light to reach the observer's eyes, producing a yellowish-red sunset. When incoming sunlight encounters a heavy concentration of particles in the atmosphere, the shorter wavelengths of light (violet and blue) are scattered away, resulting in a red sunset. Red sunsets are often observed from a beach because of the high concentration of salt particles suspended in the air over the oceans. These particles effectively scatter shorter wavelengths of light, producing red sunsets. Dust and ash particles injected into the atmosphere by volcanic eruptions can also cause red sunsets. So the color of the sky really depends on how close to a straight path the light has to travel from the sun to ...
