A phenomenon called Rayleigh scattering causes light from the Sun to bounce off tiny particles in the atmosphere and scatter in different directions. Sunlight consists of many different colours: from red, which has the longest wavelength of all visible light, through to violet at the blue end of the spectrum, which has the shortest wavelength. Due to this short wavelength, blue light is scattered more effectively than other colours, and this is why the sky normally appears blue to us.