The Color Of Sky, Is Blue of course!
And we all know why
In fact, If you are from CBSE Board
then you might have, or will later on come across an explanation for this question in
your 10th Grade on Page 196 in the  Chapter 11, titled Human Eye & The Colourful World, of your Science Textbook
It’s ofc, because of Scattering!
But what is Scattering?
Why only Blue Color? And if the Sky is Blue, then why are the clouds white?
The Problem is, Scattering is not the complete answer, for Why the Sky is Blue! In Fact, the Sky is blue also....
because of the Sun giving off Green the Most!
Now you shall understand! :)
The Video is long Yes!
I did'nt expect for this to be so long
There are two reasons for this
First
this has been divided into there sections
in which I not only talk about why the sky is blue
I have included a host of other questions, such as
How Do Humans See Color?
Why are the clouds white?
what are all the radiations that Sun emits?
If you go to the ISS, then how would Sun look like from there
How would Sun look like from other Planets?
I have tried to provide y'all with a new perspective through this video
I have included a lot of clips in between the three sections that you might have never seen before!
The length of video has increased thus
What All does Sun Emit?
Though the sun emits all of the different kinds of electromagnetic radiation, 99% of its rays are in the form of visible light, ultraviolet rays, and infrared rays.
Why does Sun emit Light? Any Body with a temperature above absolute zero (which almost all the bodies with any kind of vibrations or movements are) emits radiation, this is known as the Black Body Spectrum!
Humans give off mostly infrared radiation, which is electromagnetic radiation with a wavelength higher than visible light.
What Is Visible Light?
The Very Definition Of Light can include entire spectrum of Electro Magnetic Radiation or Just the Visible Light. The confusion pops because all of the Waves part of the Electro Magnetic Spectrum travel at “Speed of Light”
Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that can be perceived by the human eye which has waves having wavelengths of 400–700 nanometres.
All of this colors included, we get WHITE!
Did you know that Sun has an inherent Colour preference?
Sun emits most of its energy around 500 nm, which is close to blue-green light. So one might say that the sun is blue-green!
This maximum radiation frequency is governed by the sun’s surface temperature, around 5,800K.
How would The Sun look like from the ISS? As there's no atmosphere over there!
Sun Would Appear White, if viewed from ISS, as it also emits strongly in all the visible colors – red through blue (400nm to 600nm). Our brains would, then integrate these signals into a perceived white color.
Where Does The Light Go, once it reaches the Earth? The Intermediate, atmosphere!
what happens to this bluish-green light?
Rayleigh Scattering discovered by Rayleigh
Lord Rayleigh was an intellectual heavyweight, winning the Nobel Prize in 1904. But it was earlier than that, back in the 1870s, that he gave us the now-famous "Rayleigh Scattering".
Scattering is basically the light produced by the vibration of charges present in the gas molecules. When Light Waves hit the charges present in the atoms or molecules in the atmosphere, they make these charges vibrate and hence, these charges start radiating off this light to different directions.
This depends on the size of particles
If the size of particles matches that of waves, then the resonance happens more profoundly and hence those waves are scattered more
F= ma! The vibration Is, nothing but acceleration produced by the Force applied the Light Wave + Restoring Force (from the nuclei). The Closer the frequency of light to resonance frequency of particle, the higher is it scattered!
The Closer the frequency of light to resonance frequency of particle, the higher is it scattered!
So, the N & O molecules (due to their small molecular size) have strong resonances In UV and thus, favouring the scattering of UV Light most, or the light in that range.
Blue and Violet in which case being the closest to this UV, they are scattered more. This is what Rayleigh Scattering is all about!
Why are clouds White?
Bigger particles like water droplets within a cloud scatter all wavelengths with roughly the same effectiveness
All the colors together gives us White, of course!
And that is why the clouds are white!
They also appear to be Grey when there are more water particles present! Thus, even bigger particles
Why Is The Sky Dark during Nights then?
Because, of course, there’s no Sunlight, as the Earth faces away from the Sun! But what about Light from other Stars? Well, that’s what Olber’s Paradox is all about and it, is a question for another video!
Bulk Attenuation is the cause!
As sunlight travels through the thick atmosphere, it becomes progressively weaker because it is being partially scattered all along the way. The rate at which it becomes weaker is faster for higher-frequency colors.
Colors like Blue and Violet hence become weaker, faster!
During the Sunrise & Sunset, the sunlight is approaching an observer at a low angle, so it has to travel through much more atmosphere
by the time the light reaches the layer of air closest to the grounded observer, all of the green, blue and violet colours have long since been scattered out by higher layers of atmosphere, leaving just red and orange.
Thus due to Bulk attenuation, the Sky appears Orangish_Red during Sunrise & Sunset
But why does Sky not appear Violet? Why Only Blue?
If Rayleigh’s Scattering Law is observed, then other Rays (such as X Ray) have higher frequency, right? Very True! But See, earlier I said, that Sun has a preference, and it comparatively it emits less of X-Ray & then Atmosphere mostly reflects these rays off! But, still, why can’t we See it?
Secondly, these rays are reflected off of the Earth by the atmosphere, as soon as they enter.
Why can’t we See, InfraRed Rays, (which Sun emits in abundance) for that matter? This is because of the Structure of our Eye!
Eyes are made up of Rod Cells& Cone Cells.Rod Cells are for detecting IntensityOf Light, or the brightness of Light while Cone Cells, are for detecting Colour.
Now we have only one type of Rod Cells, where as 3 types of Cone Cells, which can be assumed to be  like 3 dimensions.
The Short Wavelength Preferring Cones, Middle Wavelength Preferring Cones & the Long Wavelength preferring Cones.  According to the Young-Helmholtz or Trichromatic Theory!
Pure-Blue light detecting Cone Cells are in more abundance than the Pure-violet Violet Light and hence the case! It’s basically saying that, our eyes are more sensitive to Blue than Violet
that Pure-Blue light detecting Cone Cells are in more abundance than the Pure-violet Violet Light and hence the case! It’s basically saying that, our eyes are more sensitive to Blue than Violet
Certain Snakes for example, see infrared radiation! The Wavelength of IR is higher than that of those at Visible Spectrum!
Birds can see ultraviolet Light! The Wavelength of whose is lesser than that of those at Visible Spectrum!
Although the sky is blue because of these 3 reasons, it boils down, mainly, to, Scattering and hence people say Scattering is the reason behind the Blueness of the Sky!
The question is'nt about how much you know, rather the question is about, how much ever it is, that you know, do you know it completely?
How does Sky look like on other Planets?
On Mars, the Sunrise and Sunset is Blue in Color!
