Why Does The Sun Appear Reddish at Sunrise: Sunlight, as we all know, is a complex mix of electromagnetic radiation. It most emphatically should, because you are reading this article because of a specific type of electromagnetic radiation (visible light). Electromagnetic radiation includes radio waves (used in smartphones and all wireless communication devices), infrared (used in night vision glasses and TV remotes), X-rays (used in medicine and healthcare), and gamma rays (associated with nuclear power). As previously stated, sunlight is made up of electromagnetic radiation. Although the sun emits ALL types of electromagnetic radiation, visible light, ultraviolet rays, and infrared rays make up the majority of it (heat). You may recall learning in high school science class that sunlight is purely white because it is a combination of all seven colors of the rainbow, each with its own wavelength. When sunlight (composed of different wavelength colors) reaches our planet and strikes the atmosphere, the particles present tend to scatter light with shorter wavelengths (namely, blue and violet), while allowing longer wavelength colors (such as red, yellow, and orange) to pass through. Because redder wavelengths from celestial bodies (such as the sun or moon) penetrate the layers of our atmosphere more effectively than other colors, the sun appears red when viewed near the horizon.
Because sunlight must travel through the greatest amount of atmosphere to reach the observer’s eyes at the time of sunset or sunrise. As a result, more blue light is scattered from the sun, making the sun appear redder when it rises or sets. In fact, Rayleigh scattering (named after a British physicist named Lord Rayleigh) dictates that shorter wavelengths of light (blue) are scattered more easily than longer ones (red). This is why the sky appears blue and the sun—or, on rare occasions, the moon—appears red or orange.
As light from the Sun travels through Earth’s atmosphere, it is scattered before reaching us. The amount of scattering varies depending on the color. Light with shorter wavelengths, such as violet, blue, green, and yellow, scatters more than light with longer wavelengths, such as orange and red. Because of the earth’s spherical geometry, sunlight travels farther in the thick of the atmosphere during sunset and sunrise when the Sun is at the horizon than when the Sun is at the zenith (midday). As a result, shorter-wavelength light is more likely to be scattered than longer-wavelength light. As a result, the Sun (as well as sunrise and sunset) appear reddish-orange at sunset and sunrise. The scattering is also affected by the size and number of scattering particles. The atmosphere is cool at night, and aerial particles and dust particles settle by morning, whereas they disperse by evening. As a result, the scattering is greater in the evening than in the morning.
Finally, because the earth rotates from West to East, we move towards the Sun in the mornings (eastward) and away from the Sun in the evenings (westward) (westward). The Doppler Effect is a phenomenon that contributes to this difference. In other words, the difference between morning and evening sunlight has a natural cause.
Because of light scattering, the Sun and its surroundings appear red at sunset or sunrise. The light rays from the Sun must travel a long distance through the Earth’s atmosphere to reach our eyes at sunset or sunrise. In other words, when we look towards the horizon, we see more of the Earth’s atmosphere than when we look overhead. Because blue light is largely scattered away by particles in the Earth’s atmosphere, the light reaching our eyes is rich in red.
At sunrise, the Sun’s light rays must travel a longer distance through the earth’s atmosphere before reaching our sight. Shorter wavelengths of light are scattered out during this journey, and only longer wavelengths reach our eyes. Because blue has a shorter wavelength and red has a longer wavelength, red is able to reach our eyes after the atmospheric scattering of light. As a result, the Sun appears reddish in the early morning. The sun is closer to the horizon at sunrise and sunset. Before reaching our eyes, sunlight travels through a denser layer of air and travels a greater distance. The blue light is primarily dispersed. And red light reaches us, causing the sun to appear red at sunrise. The sun is overhead at noon. Before reaching our eyes, sunlight travels through layers of air and covers a shorter distance. As a result, almost all colours of light are distributed equally. The sun seems white as a result.
During sunrise and sunset, the light must travel a greater distance through the atmosphere. The blue light is removed because it is the most scattered, whereas the red light is less scattered and thus reaches the observer. As a result, during sunrise and sunset, the sun appears reddish.
Before reaching our eyes at sunrise, the Sun’s light beams must travel a larger distance through the earth’s atmosphere. Shorter wavelengths of light are scattered out during this journey, and only longer wavelengths reach our eyes. Because blue has a shorter wavelength and red has a longer wavelength, red is able to reach our eyes after atmospheric scattering of light. As a result, the Sun appears reddish in the early morning.
According to Rayleigh scattering theory, the intensity of the light scattered depends on the wavelength as follows:
I∝ 1/λ4
This equation shows that light with a longer wavelength scatters less, while light with a shorter wavelength scatters more. When the sun rises or sets, it is just above the horizon, and the light rays from the sun take longer to reach the earth, so they must travel further through the atmosphere, where they interact with the particles in their path. We know that shorter wavelengths of light scatter more strongly than longer wavelengths. Because blue has the shortest wavelength, it is scattered more than red, and because red only reaches the earth, the sun appears red at sunset and sunrise. Light from the sun, on the other hand, travels a shorter distance in the afternoon. At noon, the Sun appears white because only a small amount of blue light is scattered, whereas near the horizon, most of the shorter wavelength light at the blue end of the spectrum is scattered away by the small particles of the atmosphere. As a result, the light that reaches our eyes has a longer wavelength, giving rise to the sun’s reddish appearance.
When faced with this type of question, it is important to remember that sunlight travels through thicker layers of air and over greater distances in the earth’s atmosphere before reaching our eyes, and that most of the blue light and short wavelengths are scattered away by particles. Sunlight has seven distinct colors. Red has the longest wavelength of all. Because the rays are so close to the horizon at sunrise and sunset, they must travel a greater portion of the atmosphere. As a result, light with shorter wavelengths than red is mostly scattered away. Our eyes receive the majority of the red light, which is the least scattered. As a result, the sun and sky appear to be red.
The scattering of light by air molecules and other small particles in the atmosphere causes the sun’s crimson hue at sunrise and dusk. The sun lingers below the horizon during sunrise and sunset, thus light from the sun travels through deeper layers of air and longer distances in the earth’s atmosphere before reaching our sight. The particles in the atmosphere scatter the majority of blue light rays and other shorter wavelength rays. As a result, only red light, which has a longer wavelength, reaches us, giving the sun a crimson hue at sunrise or sunset.
The scattering of light by atmospheric particles causes the Sun to appear red at sunrise. The light from the Sun has to travel a longer distance through the atmosphere to reach the observer at sunrise. During this time, the molecules of air and other fine particles in the atmosphere scatter the majority of the shorter wavelengths present in it away from our line of sight. As a result, the light reaching us directly from the rising Sun is primarily of longer wavelength red color, giving the Sun a red appearance.
The sun is the furthest away from the point of observation at sunset/sunrise. Because the rays must travel a greater distance in the atmosphere, the majority of the colored rays are scattered. Red rays, which are the most powerful, can travel a long distance through the atmosphere. As a result, the sun appears red at sunset and sunrise.
Also read: Dispersion of Light Through Prism
The sun's rays must travel a greater distance through the atmosphere at sunset or sunrise. Scattering removes the majority of the blue and other shorter wavelengths, allowing red light to enter our eyes. As a result, the sky appears reddish at sunrise and sunset.
Light with the shortest wavelength, i.e. blue, is refracted the most. While the light with the longest wavelength, i.e. red, is refracted the least.
Because the rays are so close to the horizon at sunrise and sunset, they must travel a greater portion of the atmosphere. As a result, light other than red is mostly scattered.
