Why does sun appe

We know white light consist of seven colors namely Red, Orange, Yellow, Green, Blue, Indigo, and Violet

The wavelength of red is maximum Violet is minimum

Sun emits white light but during sunrise and sunset sun is near the horizon of earth so, light emitted by travels more distance in earth’s atmosphere as compared to sun’s position during day time

As can be seen in the figure

Now as the sunlight enters earth’s atmosphere, the white light scatters into its different components and scattering is approximately inversely proportional to fourth power of wavelength of light as per Rayleigh’s Scattering

i.e. more is wavelength less is scattering and vice versa. So wavelength of red is maximum so during sunset or sunrise, when light travels maximum distance so scattering is maximum and all the others components of white light are scattered away and only red light reaches our eyes so sun appear reddish in color.