Sunlight, which appears white to the naked eye, is composed of a spectrum of colors ranging from violet to red. When sunlight reaches the Earth’s atmosphere, it encounters countless tiny particles, such as dust, water droplets, and molecules of gases like nitrogen and oxygen. These particles, particularly the molecules in the air, have the ability to scatter light. However, the scattering process is not uniform for all colors. The shorter wavelengths, such as blue and violet, are scattered more than the longer wavelengths, like red and orange. As sunlight enters the atmosphere, the blue and violet wavelengths undergo a scattering phenomenon called Rayleigh scattering. This type of scattering occurs when the size of the scattering particles is much smaller than the wavelength of light. The molecules in the atmosphere scatter the shorter blue and violet wavelengths in all directions, filling the sky with a vibrant blue hue. In contrast, the longer red and orange wavelengths experience less scattering and are able to pass through the atmosphere with minimal deviation. This phenomenon explains why the sky appears blue during the day, as the shorter blue wavelengths dominate the scattered light. Additionally, the Earth’s atmosphere acts as a filter, absorbing certain colors of light. This absorption further enhances the blue appearance of the sky. Hence, the blue color of the sky is a consequence of the scattering of shorter blue and violet wavelengths by molecules in the Earth’s atmosphere. This scattering phenomenon is known as Rayleigh scattering.

• This reply was modified 3 months, 2 weeks ago by  Divya Singh.