This phenomenon is most often observed either at sunrise or sunset. The sun turns red, and the sky is colored with orange, crimson and maybe even purple tones.
It’s a poignant romantic scene, but above all for a scientific reason.
See for yourself, but remember never to look directly at the sun! And do not even think about trying to look at her through binoculars or telescopes, as this may destroy your eyesight and cause you permanent blindness.
The best scene ever
You may not be able to describe this magical scene in your words, but here is my secret: Light Scattering.
Sorry to spoil the magic, but it all goes back to the basic rules of physics and “the optical properties of sunlight crossing the atmosphere,” says Edward Plumer, an astronomer at the Royal Greenwich Museums in Britain.
First, we need to understand the nature of light, which consists of all the colors of the visible light spectrum (red, orange, yellow, green, blue, indigo and violet.
“It’s about the scattering of sunlight,” says Blumer, “and this scattering does not happen equally,” because each color has a different wavelength, and this is what makes each color look like the image we see.
For example, the wavelength of violet is the shortest, while the wavelength of red is the longest.
The second step is to understand our atmosphere, that is, the layers of gases surrounding our cup that make life possible on it, including the oxygen we breathe.
Light aFor dispersed
As sunlight passes through the different layers of the atmosphere – which contain gases of varying density – it bends and refracts as if it were passing through a prism.
There are also particles suspended in the atmosphere, which in turn cause the refracted light to bounce and reflect.
When the sun rises or sets, its rays collide with the upper layers of the atmosphere at a certain angle, and this is where the “magic” begins.
Once sunlight penetrates these upper layers, the blue wavelengths are refracted and reflected rather than absorbed.
“When the sun is low on the horizon, all the blue and green colors are dispersed, while the orange and red colors reach us,” Blumer added.
This happens because the short wavelengths of violet and blue are scattered more than the long wavelengths of orange and red. The result is an array of gorgeous colors in the sky.
But the sky looks very red!
Yes, it may look like it is, but this is only what it looks like, and the sun has never changed.
Depending on where you are in the world, your sky may appear more dazzling at this moment, due to local weather conditions.
“Clouds of dust, smoke, and other things may affect the image you see in the sky,” says Blumer.
Thus, if you live in India, California, Chile, Australia or in certain areas of Africa, the atmosphere may be filled with more reflective particles according to the weather conditions.
“It looks a bit like it does on Mars, when red dust is released into the air, giving the impression that the sky is pink and tends to be red,” he added.
Even if you live far from the desert (or Mars!), You can still see these magical skies. Desert sands often rise to the upper atmosphere and move towards Europe and perhaps even further into Siberia and even the Americas.
Why is this happening now?
It may not be so unique what is happening, but what has changed is that we are starting to notice things differently.
“During the lockdown we noticed that people were paying more attention to the sky, maybe because they didn’t have much to do!” Plumer says with a smile.
With cinemas, theater and nightlife activities closed, Bloomer adds, we are sitting at home for longer times flying out the window. Decreased air traffic and a slight decrease in pollution rates have also revived people’s interest in the sky and stargazing.
Make me a rainbow
The phenomenon of light scattering also explains the reason why the sky appears blue in the middle of the day.
As the sun rises in the sky, and its rays pass through the atmosphere without being refracted, they are absorbed and the predominant visible color is blue. Of course, things can change according to weather conditions.
If the rain falls and the sun is bright, the light is scattered to its different wavelengths with every drop of water, and the colors are dispersed in the air.
Thanks to physicist Lord Riley, who studied sunlight and the atmosphere during the nineteenth century, he was the first person to come up with an explanation for why the sky was blue.