Why is the sky blue?

The Sky’s Blue Color

The answer to the question why is the sky blue during the day when there are no clouds is the presence of molecules in the atmosphere that serve to scatter away from the sun blue light more than the red light. When we take a look towards the sun in the course of sunset, we see orange red colors owing to the fact that the light that is blue in color has already been scattered away and out of the sight line.

The white light that is produced by the sun is a blend on all the colors on the rainbow. This was shown by Isaac Newton who made use of a prism to distinguish different colors and thus result in a spectrum. The light colors are separated using the differing wave lengths. The part of the spectrum that can be seen ranges from light which is red in color that has a wavelength of approximately 720nm to violet light that has a wavelength of approximately 380nm having indigo, blue, green, yellow and orange in the middle. The three distinguishing kinds of color receptors found in the human eye retina respond with much strength to blue, green and red wavelengths providing us with the color vision.

The Tyndall Effect
The initial steps towards giving the right explanations as to why is the sky blue were taken in 1859 by John Tyndall. He made the discovery that when light goes through a clear fluid having in suspension small particles, the blue wavelengths that are shorter scatter with more strength than the red ones. This is more rightly referred to as the Tyndall effect but it is more frequently referred to as the Rayleigh scattering by the physicist after Lord Rayleigh who conducted more detailed studies of this a number of years later, he demonstrated that the amount of light that is scattered has an inverse proportion relation with the fourth power of wavelength for particles that are sufficiently small. This goes to say that blue light gets scattered more than the red light by a (700/400)4=10 factor.

Dust or Molecules?
Rayleigh and Tyndall thought that the answer to the question why is the sky blue is the presence of water vapor droplets and small dust particles in the atmosphere. Even currently, a number of people wrongly assumed that this is the reason. Later scientist’s acme to the realization that if this was the answer to the question why is the sky blue then the sky would have a larger variety of colors. They also found out that the sky would have observable haze or humidity conditions. They then correctly supposed that the nitrogen and oxygen molecules in the atmosphere are enough to explain the scattering.

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