Breakdown: Why sunsets appear reddish

Why sunsets appear reddish

MEMPHIS, TN (WMC) - When it comes to visible light, red light waves are scattered the least due to atmospheric gas molecules.

At sunrise and sunset, light has to travel farther before it gets to you. More of the light is reflected and scattered and the sun appears dimmer. When the sunlight travels a long path through the atmosphere and it reaches our eyes the blue light has been mostly removed, which leaves mostly red and yellow light that remains.

Light is refracted by particles in the atmosphere and the red end of the spectrum is what is most visible.

So why does light scatter?

The Earth’s atmosphere is one of the biggest factor in the outcome of the color of a sunset. The atmosphere is composed of mostly gas with a few other molecules too. It completely surrounds the Earth and affects what you see. The most common gasses in our atmosphere are nitrogen (78 percent) and oxygen (21 percent). The remaining small percent is made up of trace gasses, like argon, and water vapor and many tiny solid particles, such as dust, soot and ashes, pollen, and salt. After a storm there may be more water in the air or close to the ocean. Volcanoes can put a lot of dust particles high into the atmosphere. Pollution can also contribute to different gases or dust and soot. The colors contain different wavelengths, frequencies, and energies. Violet has the shortest wavelength and will have the highest frequency and energy. Red has the longest wavelength but lowest frequency and energy.

Light will move in a straight line until something gets in it’s way like (gas molecule, dust, or anything else). What happens to that light will depend on the specific wavelength of the light and the size of the particle. Dust particles and water droplets are bigger than the wavelength of visible light, so it will bounce in various directions. If a light hits a gas molecule, it may get absorbed. The molecule radiates the light in all different direction.

The color that is radiated is the same color that gets absorbed. The different colors are all affected differently. Every color can be absorbed, but the higher frequencies (blues) are absorbed way more frequently compared to the lower frequencies (reds). This process is known as the Rayleigh scattering.

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