Why the sky is blue and sunsets are red??
Everyone in their lifetime have atleast once looked at the huge umbrella of blue colored sky above in amazement.
The beautiful drawing created sometimes with the clouds, with the golden ball called as sun looking at us with a huge smile... Well putting brakes to the imagination train and getting down for the sake of understanding the curious question in hand.
Why the sky is of the color it is! Why blue most of the times and why it gets a tint of orange and red early mornings and late evenings.
To give a brief answer to it, this is related to concept of Scattering of Light.
So the golden ball that we spoke about, the SUN emits light in form of rays which reach out to the earth travelling a huge distance around 93 million miles i.e. ~ 150 million kms.
Now this distance is not constant and it changes to a specific point on earth as the earth tries to complete its orbit around sun and itself.
Coming back to the concept of scattering, a light is basically a composition of many spectrum of colors which have different wavelength.
Too many complex words in a statement??
Let me try to simplify this..
Light is basically a form of energy waves. In this energy there is part of it which is visible to the human eye. That visible light in itself has a wave form in it (Imagine a big wavy line, cut that wave in middle. You would still have a small but still a wavy line right).
Consider different points on this small wavy line based on the height. That is called as wavelength.
These different wavelength are visible to us in form of colors. Remember VIBGYOR ( Violet, Indigo, Blue, Green, Yellow, Orange, Red ) that you might have touched upon.
Going from shortest to longest we have,
Violet < Blue < Green < Yellow < Orange < Red.
So, when sun light enters the earth's atmosphere, the light gets scattered due to presence of atoms and molecules of the gases present in the air. The light gets further reflected and scattered in the atmosphere. Scattering happens when the light waves hits the gas molecules and are not absorbed by them. Air molecules do not scatter all wavelength equally, the shorter wavelength (violet, blue, green) is scattered more than the longer wavelength(yellow, orange, red)
And as per Rayleigh's scattering theory, the higher the wavelength the less the spread. So looking at above comparison you can understand which color will spread more.
Why not violet or mix of violetish blue or bluish violet or greenish blue. A one half of the reason would be the scattering of the violet and the other half could be the sensitiveness of the color blue to our eyes.
Now you might ask why during sunsets the color becomes red?? The answer is in the distance between the specific point on earth with the sun. The sunlight now has to travel a longer distance to reach to earth. So now the light has to pass through more of the atmosphere which leads to the heavy scattering of blue light due to its shorter wavelength. This makes the yellow red color tint available to be seen through our eyes.
This is why we see a yellowish-orangish red tint in the sky!!
See how the wavy visible form of energy shows a different range in colors. And the main reason is how the presence of different gases in atmosphere which creates a phenomenon of scattering of light.
So, do you think on other planets as well, there is a bluish sky in the day and reddish one during the sunsets? Well it depends on which planet are we talking about and how is the atmosphere over there.
For example, in case of planet Mars which has a thin atmosphere filled with carbon dioxide and dust particles it's an orangish/reddish tint in the sky while sunsets produce grayish blue color.
Do you know since on the moon there is no atmosphere present, all the light travels without scattering onto its surface. So when we would look towards the sun it would a big ball of white light and looking away would be a dark empty space.
You got to know about the sky, but do you know why the blue sea?? Check below article to know why
Why the sea is blue - The Raman Effect
Until next time, remember the curious mind talks
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