No, you often hear that, but-assuming you mean typical pollution in the lower atmosphere-it's a myth. It's rather disquieting when really you start thinking about it!ĭo dust and air pollution make sunsets more dramatic? Absolutes don't really exist in color perception. And as humans, we like to think color is concrete: 'Oh, that's a blue sky,' or 'That's a brown table.' But the colors you see depend on the light's path before it got to you, how the object you are viewing reflects that light, and what your eyes are sensitive to. Yes, I think a lot of people don't realize that. So the same ray of sunlight is hitting people in both the Rockies and the Appalachians? Basically, the East gets the West's leftovers at sunset? The blues could be somewhere over the West Coast, leaving a disproportionate amount of oranges and reds as that beam of light hits the East Coast. It means that much of the blue has scattered out long before the light reaches us. And that is enough to make a big difference as far as our human eyes are concerned. The daytime sky would actually look purple to humans were it not for the fact that the sensitivity of our eyes peaks in the middle part of the spectrum-that is, closer to blue than to purple.īut at sunset, the light takes a much longer path through the atmosphere to your eye than it did at noon, when the sun was right overhead. Basically, that's why the daytime sky is blue. That means that they preferentially scatter the shortest wavelengths, which are the blues and purples. The two main molecules in air, oxygen and nitrogen, are very small compared to the wavelengths of the incoming sunlight-about a thousand times smaller. This happens millions of times before that beam gets to your eyeball at sunset. When a beam of sunlight strikes a molecule in the atmosphere, what's called 'scattering' occurs, sending some of the light's wavelengths off in different directions.

Why do we see more orange and red colors in the sky during sunrise and sunset than we do at other times of day? Okay, so let's talk about the typical Earthling's perspective. But as the plane gets above the boundary layer, into cleaner air, suddenly the sunset looks very vivid. It might not look like anything special from the ground, just a whitish-pink sky, because you're still within the atmosphere's 'boundary layer.' That's where all the large particles are trapped, things like dust and pollution. You may have noticed this if you've ever taken off in an airplane at sunset. So really, there's a good sunset every night we just can't always see it from the ground.

Portions of it are absorbed and filtered out in the atmosphere. Different colors are associated with different wavelengths.Īnd depending on what happened to the light before it got to you, some of those visible wavelengths don't even reach your eye. That radiation contains a wide spectrum of wavelengths, but your eyes are only sensitive to certain parts of it: the so-called visible wavelengths. Keep in mind that what we see with our human eyes is just a tiny part of the electromagnetic radiation that's given off by the sun. I guess it depends on how you define 'good,' but I'm going to assume you mean a strikingly colorful one, where the colors are spectrally pure-say, vivid orange or red-as opposed to a more muted palette. In simple terms, what makes a good sunset happen? We asked Stephen Corfidi, a National Oceanic and Atmospheric Administration (NOAA) meteorologist who's written about the science of colorful sunsets, to help us see the light. The scarlet skies inspired many viewers to grab their cameras, and prompted a question: Why are some sunsets so spectacular, and others a mere muddle? Rage, rage against the dying of the light.

On a recent autumn night here in Washington, D.C., the sun seemed to personify a Dylan Thomas poem: Do not go gentle into that good night.

Colorful wave and sunset