Few things in nature are as inspiring as a colorful sunset. Factors, such as time of year and location, can affect the color and intensity of the show. America's Wild Rivers Coast's varying landscape and clean air offer extraordinary opportunities for viewing twilight splendor. Along the coast, sunsets are most beautiful because of an unobstructed horizon.
What makes the sunset red?
To understand why the sky is orange and red at sunrise and sunset, it is easiest to begin by explaining how sky colors are produced.
Typical sunlight is composed of a spectrum of colors that range from violet and blue at one end to orange and red on the other. These wavelengths vary in size.
The Earth's atmosphere is composed of tiny molecules, thousands of times smaller than the wavelengths of light. "Selective scattering," or Rayleigh scattering, is used to describe scattering that varies with the wavelength of light. The atmosphere selectively scatters the shorter wavelengths, violet and blue, much easier than longer wavelengths.
The sky appears blue to to the humans because the eyes are more sensitive to blues than to violets. It's this same scattering effect in water that makes the ocean appear blue, even though water itself is clear.
Remember, there is a sunrise and a sunset somewhere on the Earth at all times. As the Earth rotates, the angle of the sun relative to the horizon determines how much of the troposphere (lower atmosphere) sunlight has to pass through to reach human eyes. Because an increased amount of violet and blue light is scattered out of the beam along the way at sunrise and sunset, more red and orange reaches the surface of the Earth.
Does pollution make for more colorful twilight?
Clean air is the No. 1 ingredient for brightly-colored sunrises and sunsets. The airborne dust and haze present over large cities does not scatter light the same way pure air does. This often imparts a grayish or whitish hue to daytime skies and, instead of vibrant oranges and reds at sunset, the sky appears pale yellow and pink. In addition, the haze reduces the amount of light that gets to the ground, resulting in less-brilliant, or even dull, twilight colors.
What about clouds?
Certain types of clouds can enhance sunsets. Cirrus and altocumulus clouds are high enough to catch the unfiltered sunlight. these high clouds can reflect he facing sun's light, often casting a red-orange hue over the entire landscape. Low clouds can also take on intense coloring, but this is often limited to areas where the air is otherwise free of haze.
Sunsets provide bonus shots
When photographing a sunset, don't forget to look at how the low sun is lighting objects. A setting sun brings out the colors and shadows on a small headland north of Arch Rock Viewpoint. Early morning light will create a similar effect.