Light that looks white to our eyes actually is made up of many different colors. Each color can be thought of as a light wave with a different wavelength or size. Within the small range of wavelengths or colors that we can see with our eyes, the shorter waves are blue and the longer ones are red. Colors such as green, yellow, and orange lie in between the blue and red ends of the visible spectrum. When light comes from the sun, all these light waves of different wavelengths travel through empty space.
Because of the extremely small size of visible light waves less than one millionth of a meter , these light waves also interact the tiny gas molecules that make up the air itself. The light waves bounce off these particles just like you might bounce and get jostled in a busy hallway. As the light waves bounce in lots of different directions, we say they have been scattered. How light waves get scattered depends strongly on the size of the particle compared with the wavelength of the light.
Particles that are small compared with the light wavelength scatter blue light more strongly than red light. The sky takes on these vivid hues due to a phenomenon called Rayleigh scattering. The sunlight that we see is a type of electromagnetic radiation that is emitted by the Sun. Known as the visible light , it looks white but is composed of colors of different wavelengths, with violet having the shortest wavelength and red having the longest.
You can see the different colors when you look through a prism or when a rainbow appears in the sky. In addition, water molecules in the form of droplets, ice crystals, and vapor, and particles such as dust, pollutants, and ash can be found in the atmosphere, which is denser closer to the Earth and thins out as the altitude increases.
The Sun's rays have to travel a shorter path through Earth's atmosphere in the day. This is why the sky looks blue during the day. When sunlight strikes gas molecules, such as nitrogen and oxygen, light of longer wavelengths, like red, yellow, and orange, easily passes through, while light of shorter wavelengths, such as blue and violet, is absorbed and then scattered in all directions by the gas molecules.
It means that much of the blue has scattered out long before the light reaches us. 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. 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? Yes, I think a lot of people don't realize that. Everything is connected.
And as humans, we like to think color is concrete: "Oh, that's a blue sky," or "That's a brown table. Absolutes don't really exist in color perception. It's rather disquieting when really you start thinking about it! No, you often hear that, but—assuming you mean typical pollution in the lower atmosphere—it's a myth. It's actually the opposite: Large particles in the lower atmosphere tend to mute and muddy the colors because they absorb more light and scatter all the wavelengths more or less equally, so you don't get that dramatic filtering effect.
In areas with a lot of haze, you don't typically see the types of sunsets that are likely to appear on a wall calendar— or in, say, National Geographic. You see bright ones in the fall and winter particularly, especially in the East, because the air along the path of the ray of sunlight tends to be dryer and cleaner. I grew up in Baltimore, and this is part of why I got interested in weather.
I would wonder: Why is the sunset so pretty tonight? And there weren't answers to questions like this in standard weather books, because it's more about physics than forecasting. Speaking of forecasting, what about the saying: "Red sky at night, sailor's delight; red sky in morning, sailors take warning. Those spectrally pure colors are telling you there's a sizable swath of clear air off to your west that's likely to be over you the next day.
Yeah, you can forecast them to a certain degree. I guess it's a question of who cares—maybe filmmakers or photographers would find that information useful, but most people just want to know if it's going to rain or not. There's often a slanting band of clouds on the back side of the departing weather system, and that can act as a sort of projection screen for the low-sun colors, better than a horizontal band would.
The slant means it captures more of the orange and red light, and if the cloud is thin enough, it will reflect those colors down to you. Also, storms wash a lot of the big particles out of the air.
Yes, true sunset occurs a minute or so before you see the sun disappear. What you see is a kind of mirage; the light is getting bent around the horizon by the effect of refraction. Our eyes are sensitive to a very tiny part of the spectrum of the sun's wavelengths, and that's responsible for the way we see our environment. Other creatures seem able to see the ultraviolet area of the spectrum.
We can only see a tiny part of what's going on. So a butterfly or a reindeer , which can perceive ultraviolet light, might be seeing a different, perhaps more colorful sunset than we do? The more you look at things, the more you realize how unique your own experience is as a human on this planet, at this particular place and time.
All rights reserved. In simple terms, what makes a good sunset happen?
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