Have you ever stood in awe of the sky as it basks in the warm hues of red and orange during the early morning or late evening? This daily spectacle of nature is not just a feast for the eyes but also a fascinating phenomenon explained by the science of atmospheric optics. The reason why the sun appears red during sunrise and sunset has to do with the way sunlight interacts with Earth's atmosphere. The journey of sunlight to our eyes is a complex one. When the sun is high in the sky, sunlight takes a relatively direct path to reach us. The shorter wavelengths of light (blues and violets) are scattered in every direction by the gases and particles in the Earth's atmosphere, which is why the sky appears blue during the day. However, at sunrise and sunset, the sun's light must pass through a greater thickness of the Earth's atmosphere compared to when the sun is overhead. This increased distance through the atmosphere means that more scattering occurs. The scattering of light by molecules and small particles in the atmosphere is described by Rayleigh scattering, named after the British physicist Lord Rayleigh. According to this principle, shorter wavelengths of light are scattered more easily than longer wavelengths. During sunrise and sunset, the light has to travel through more air, and consequently, even more of the shorter blue wavelengths are scattered out of the direct path of the light by the time it reaches our eyes.