During noon time we can see the sun glowing with extreme intensity. During early morning, to be precise, during sunrise the colour of the sun will be somewhat red. During the evening before the nightfall the colour of the sun again turns to red. Why did this happen? To answer this question, we have to dive deeper into physical world of optics. White colour is the combination of all colours. We all know that. Major component of white colour is7 primary colours , violet, Indigo, blue, green, yellow, orange and red. These colours are arranged according to their wavelengths. Among these colours red has the highest wavelength. It is due to this property red is used as an important colour in emergency messages. During sunrise, the colours upto blue gets dispersed in the atmosphere due to its lesser wave length. This scattering give the sky blue colour during the sunrise. The only colour which reaches our eyes during the sunrise is red due to its higher wavelength. The same property appears during the sunset and the sun appears to be red in colour during both sunrise and sunset.