Is the sun blue

Video: why is the sky blue?

If you look at the sky from space on a summer's day, it is black, the light of the sun glistening white. Seen from the earth, the colors appear different: the sky is bright blue, the sun casts a warm, yellow light.

Blue sky by colored light of the sun

Why the sky appears blue when viewed from the earth is due to the nature of the sunlight. The light of the sun consists of individual rays of light that move in waves. If you see all the light rays at once, the light appears white. However, if the light is deflected, for example by a prism, individual spectral colors such as red, orange, yellow, green, violet or blue become visible. The rays of light from the sun thus consist of bright colors.

The Rayleigh phenomenon explains the blue sky

On their way to earth, the sun's rays penetrate the earth's atmosphere. This consists of invisible gas molecules, mainly nitrogen and oxygen. If the rays of light from the sun hit these small particles, they are deflected or scattered. Since each color has a different wavelength, the spread is different. When the sun is high in the sky, the path that light has to travel through the atmosphere is relatively short. Above all, blue light is scattered - the sky appears blue. This phenomenon is also called Rayleigh scattering. The Englishman John William Strutt, 3rd Baron Rayleigh, discovered the physical principle that causes the blue sky in the 19th century.

Red sunlight creates color at sunset

At sunrise or sunset the sky shows different colors than the blue during the day. Variations of red tones replace the blue and the sun, which appears yellow during the day, also appears red. This is because the sun's rays have a longer path through the atmosphere in the morning or in the evening, because the sun is lower: it is mainly red light that is scattered. Because: After a short distance, the molecules intercept the short-wave blue light; only the long-wave red rays arrive on earth. This will be visible as sunrise or sunset.

Experiment with flashlight - sun and blue sky

If you pour milk into a large transparent glass with water, you can imitate the light scattering in the sky. The fat molecules in milk, in the role of molecules in the atmosphere, scatter the light of the flashlight. The light appears blue, the light source creates a yellowish glow like the sun.