Why does the sky turn pink? (2024)

FAQs

Why does the sky turn pink? ›

Answer and Explanation: The sky appears pink sometimes in the evening because the angle of the Sun is lower to the Earth's atmosphere and light is scattered as it passes through the clouds. Since the Sun is lower, it has to pass through more atmosphere to get to our eyes compared to when it is higher in the sky.

Answer and Explanation: It is thought that for sailors, the sky's color meant certain impending weather. A pink, or technically red, sky at night meant good weather for the next day. This is because as the sun is setting, its light is traveling through the lower parts of the atmosphere.

The short answer

Sunsets can turn the sky pink because of a phenomenon called scattering, where the shorter-wavelength blues and violets are scattered, leaving the longer-wavelength yellows, oranges, and reds to be more visible.

As light interacts with particles in the atmosphere, it gets bounced around and scattered, enabling us to see certain colours more vividly. But a low sun meant light had to travel further to reach us, scattering blue light elsewhere and leaving us with the redder end of the spectrum.

Similarly, the vibrant oranges and reds of "clean" sunsets give way to pale yellows and pinks when dust and haze fill the air. But airborne pollutants do more than soften sky colors. They also enhance the attenuation of both direct and scattered light, especially when the sun is low in the sky.

Blue light usually dominates the color of the sky but when dust or smoke is present, the larger particles scatter (or block) much of the blue light while the longer wavelength of red light passes through the particles.

“Pink skies at night” are typically a sign of more pleasant weather conditions on the way, as the clouds which brought us rain or snow are moving east and away from our region.

They are normally seen near sunset or sunrise as that is when only the longest wavelengths of light can make it through a thicker atmosphere without scattering away. Pink is a shade of red and it is sometimes visible at this time.

This is partially due to "the optical illusion of the pink wavelengths lighting up the base of the cloud (due to the low angle of the sun's rays), and these pink clouds superimposed on a dark blue sky. The combination of pink and dark blue can make the sky appear a deep purple."

Technically, the short wavelengths that scatter across the sky correspond to the colours blue and violet, making the real colour of the sky a bluish purple. However, the cone cells in our eyes that detect colour aren't very sensitive to violet, so we see the sky as blue.

Is the sky colorful because of pollution? ›

Nitrogen and oxygen make up most of the molecules in our atmosphere, but any gas or aerosol suspended in the air will scatter rays of sunlight into separate wavelengths of light. Consequently, when there are more aerosols in the atmosphere, more sunlight is scattered, resulting in more colorful skies.

Setting or rising sun in orange-red colours

If the air is very humid, the large number of mini-droplets of water makes it look even milkier. And if pollution gets in the way, it can further enhance the absorption of certain colours, and the colour of the sky can take on yellowish or reddish tones.

Although extreme weather events like volcanic eruptions have been known to produce brilliant sunsets due to the increased emissions of particulate matter, their presence doesn't always mean prettier skies.

The Short Answer: Gases and particles in Earth's atmosphere scatter sunlight in all directions. Blue light is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.