WHY RED SKIES ARE BEAUTIFUL NOW
Red skies at sunrise and sunset are especially prevalent and particularly ravishing in autumn and winter. So we are on red sky alert, now until springtime.
The prevailing myth about colorful sunsets is that their color drama is caused by pollutants in the lower atmosphere. But actually, the opposite is true. Pollution’s particulates mute and muddy color because they absorb more light, relative to the light they reflect -- and they scatter all wavelengths more equally, so no pure color pops.
So, while red skies occur year round, the reds are more vibrant in autumn and winter months, because the air in our troposphere tends to cleaner and dryer, after seasonal storms, yielding colors that are more spectrally pure.
“Red sky at night, sailors’ delight.
Red sky at morning, sailors’ take warning.”
--- Ancient mariner’s rhyme
Red skies have long been used as weather forecasting tools because they are impacted by wind and humidity. Due to the rotational direction of the Earth, from most vantage points on the globe, the redder the sunset, the clearer the weather coming in from the west on prevailing westerly winds. At extreme polar latitudes, however, the prevailing winds are from east to west.
Sunsets are often more dramatic after a major storm because bands of storm clouds tend to slant as they move away, projecting even more the sun’s reddish colors.
National Oceanic & Atmospheric Administration (NOAA) meteorologist Stephen Corfidi explains the science of red sunsets, in fascinating detail. Here are more highlights:
Color perception is affected by scattering, when a beam of sunlight strikes molecules in the atmosphere, sending different wavelengths off in different directions. Oxygen and nitrogen, the two primary molecules in air, are about one thousand times smaller than the wavelengths of sunlight entering our atmosphere.
During the day, when sunlight is more directly hitting the earth, more of the shortest wavelengths of light (purple & blue range of spectrum) bounce off these molecules and scatter, so the sky appears as blue.
We see more red and orange colors in the sky during sunrise and sunset, vs at other times of day, because the angle of the sun’s rays when it’s at the horizon, when the shorter wavelengths purple and blue light are more scattered and longer wavelengths of red and orange light endure. In essence, sunset’s red light is “leftover” light. The process is known as Rayleigh scattering.
While we tend to notice the days when exceptionally beautiful and dramatic sunrises and sunsets happen, they actually happen every morning and evening. If you’ve ever flown in a plane during these hours, you might have seen the gorgeous color outside your window any day of the year, regardless of what the sky looked like that day from the ground.
That’s because at ground level, the atmosphere has a "boundary layer," where large particles of dust and pollution are trapped, thereby muting the colors. Planes fly above this level, in cleaner air, so the colors are more vivid.
Here are some especially beautiful places to view the red rosy fingers of dawn. And here of some lovely sunset inspirations. Enjoy autumn’s red skies. And share your photos with us!
Read more about Beautiful Reds all this week on BeautifulNow. And check out more beautiful things happening now in BN Wellness, Impact, Nature/Science, Food, Arts/Design, and Travel, Daily Fix posts.
Want more stories like this? Sign up for our weekly BN Newsletter, Like us on Facebook. Follow us on Twitter, Instagram, Pinterest. Join our BeautifulNow Community and connect with the most beautiful things happening in the world right now!
Do you have amazing photos? Enter them in this week’s BN Photo Competition.
