The color of the Sun as perceived from Earth is primarily due to the scattering of sunlight by the Earth's atmosphere. The Sun emits light across a broad range of wavelengths, including those in the visible spectrum. However, when sunlight passes through the Earth's atmosphere, it undergoes a process called Rayleigh scattering.
Rayleigh scattering preferentially scatters shorter wavelengths of light (blue and violet) more than longer wavelengths (red and orange). As a result, when sunlight interacts with the Earth's atmosphere, the blue and violet light is scattered in all directions, while a larger portion of the longer wavelength light, such as red, orange, and yellow, continues on a relatively straight path towards us.
The scattered blue light is what gives the sky its blue color during the day. The remaining sunlight that reaches our eyes, after the scattering process, appears to be a mixture of different colors. This combination of colors, when seen together, gives the Sun a yellowish appearance.
The precise color of the Sun can vary depending on atmospheric conditions, such as pollution, haze, or particles in the air. During sunrise or sunset, when the Sun is lower on the horizon, the light has to pass through a thicker layer of the atmosphere, which scatters more of the shorter wavelengths. This scattering effect results in a greater proportion of longer wavelengths reaching our eyes, making the Sun appear more orange or even red.
In summary, the Sun appears yellow because of the way its light is scattered and filtered by the Earth's atmosphere, with the specific color perception influenced by atmospheric conditions and the angle at which we observe it.