Why Is The Sky Blue?

Because of the atmosphere (the air all around us) light from the sun doesn't travel to us in a straight line.  If there were no atmosphere on earth, the sun would look like a bright orb in a black sky (that is how the sun does look from the moon).


Instead the light from the sun collides with air particles (molecules) in the atmosphere.  The sun emits light in a range of colours, most simply categorised as red, green, blue, ultraviolet. Red has the longest wavelength, which is bigger than most of the molecules in the atmosphere.  As a result, red light passes straight through air molecules, it doesn't get reflected somewhere else (or 'scattered').  

Green light has a shorter wave-length than red, and gets scattered a little.  Blue light though has a wave-length that is very close to the same size as an oxygen atom.  So the blue light bounces right off the oxygen atoms (Rayleighy scattering) in our air in any possible direction.  Ultra-violet light gets even more scattered, but we don't see in UV so we wouldn't know.

Because blue light is coming at our eyes from all directions our brains just averages it out and says 'That sky is blue'.

Ah yes, one of those questions that every parent gets asked at some time or another! The blue colour of the sky is due to something called Rayleigh scattering, or in lay-mans terms, it is all down to light wavelengths passing through the atmosphere. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air. However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Because you see the blue light from everywhere overhead, the sky looks completely blue. When you look closer at the horizon, the sky appears much paler in colour. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The colour of the sky near the horizon appears white to the human eye. So now you can very intelligent whenever a child asks you why the sky is blue!

During the day time the sky appears to be Blue in colour, because of the air scattering sunlight. The sky is a portion of the atmosphere or of external space noticeable from the surface of the earth.

The blue colour emerges because of Rayleigh scattering. As light shifts through the atmosphere, the majority of the longer wavelengths pass directly through. Nevertheless, most of the shorter wavelength light is taken in by the gas molecules. As you see nearer to the horizon, the sky looks much paler in colour. To reach to the human eye the spread blue light has to pass through more air, hence some of it gets distributed away again in additional directions.

This causes less blue light to reach your eye, and so the colour of the sky close to the horizon comes into view as white.

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.  When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.
The white light from the sun is a mixture of all colours of the rainbow.  This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum.  The colours of light are distinguished by their different wavelengths.  The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between.  The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.

to find out more:math.ucr.edu

The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.

However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.

The sunlight enters the earth atmosphere with an angle about 35 to 45 degree which makes the light look blue in colour and this happens due to divergence of light which is splitting of light into vatious colours.Since it is getting inside the atmosphere at 35-45 degrees angle the sky appears as blue to us.

Yes,confucious is right except the inventor of the scattering of light..it was not newton but C V Raman .he was awarded noble prize for this discovery..the principle is known as "Raman scattering of  light"

I don't think the sky is really blue. I think particles in the air reflect light, the atmosphere also reflects this color onto the water on the earth.

The sky is blue because it is tinted by the oxygen contained in the atmosphere.

Well Texas,that's a difficult one. Mostly has to do with our Atmosphere,that is made up of 78% Nitrogen,21% Oxygen and whats left over are traces gas ,dust and other particles.Now how light reacts to these elements is how we get the color blue.Light is an energy that Radiates or travels in Waves.Light is a Wave of vibrating electric and magnetic fields.It is a small part of a larger vibrating electromagnetic field that we call the Electromagnetic Field.Visible light is part of the Spectrum that we can see.Like when we see a Rainbow in the sky.At one end we can see Reds & Oranges and gradually shade into Yellow,Green,Blue,Indigo & Violet.Now Red has the longest Wavelength and Violet has the Shortest.Light travels thru space in a straight line as long as it is not disturbed.As it passes thru our Atmosphere it travels in a straight line until it runs into Gases and Dust.
What happens next depends on the lights wavelength and the size of the object it hits.
As the light passes thru our atmosphere the longer wavelengths(the strongest,Reds & Oranges) pass right thru.They are just to stronge to be effected by whats in our Atmosphere.The shorter Wavelengths(the weakest,Blue,Indigo & Violet) are absorbed by
the Gases and Molecules.The absorbed Blue lights are Radiated into different directions.
It gets scattered all over the sky.Wherever you look some of the scattered light reaches
you.Since you see the Blue light overhead,that is why the Sky is Blue.

The blue color of the sky is due to Rayleigh dispersion. As light travels throughout the environment, the majority of the longer wavelengths surpass directly through. Little of the red, orange and yellow light is exaggerated by the air.

Rayleigh scattering is the main factor for blue color. The blue light absorbed from the sun by the gas molecules gives us blue sky look. For more information, why the sky is blue please visit the following link.
Blue Sky

I thought the term was Tyndall scattering, the same process that produces the iridescent blue on a butterfly wing.

The sky seems blue for the reason that after sunlight filters through the oxygen in the atmosphere, all other colors except blue are absorbed by the oxygen. This is the fact that color of the sky is not so blue but it is black though, is because just twenty percent of the atmosphere is oxygen.

Silly answer : If it was not blue we would not call it sky blue DUH!

Because of the sun rays it appears to be blue but when the sun goes down over the horizon or when you catch the a morning sunrise in the sky it it appears red and gold around the sun...why is it blue we can ask God...why does the ocean look blue because if you took a gallon jug out of the ocean it is far from the color blue but looking from a distance it appears to be blue. Joy

Well Sky is not exactly Blue, According to my opinion don't go in its complexity. Sky is Blue because God Who Created this universe wished to make it Blue.

The atmosphere is the mixture of gas molecules and other materials surrounding the earth. It is made mostly of the gases nitrogen (78%), and oxygen (21%). Argon gas and water (in the form of vapor, droplets and ice crystals) are the next most common things. There are also small amounts of other gases, plus many small solid particles, like dust, soot and ashes, pollen, and salt from the oceans.
The composition of the atmosphere varies, depending on your location, the weather, and many other things. There may be more water in the air after a rainstorm, or near the ocean. Volcanoes can put large amounts of dust particles high into the atmosphere. Pollution can add different gases or dust and soot.
The atmosphere is densest (thickest) at the bottom, near the Earth. It gradually thins out as you go higher and higher up. There is no sharp break between the atmosphere and space.
All the info is in this site: http://www.sciencemadesimple.com/sky_blue.html

When the sunlight passes through the atmosphere it is colored by the types of gases it passes through such as oxygen which gives the blue tinge I am told.

The sky looks blue because the gas molecules in the air scatter light from the sun. The sun emits all colours of light, but the gas molecules in the air scatter only a section of this light (the blue colour). This means only this blue colour light gets bounced around in all the molcules of the air, making the sky look blue.

Its only the blue colours because blue light has a short wave frequency.

During the sunset the sky can also look red. This is because here the suns light is traveling further towards us, which means more of its light is scattered, which means it doesn't just appear blue.

It's the atmosphere reflecting the light. Blue is the shortest wavelength.

Because of rayleigh scattering  www.sciencemadesimple.com

Because old soldiers died and painted it that way.

Actually, the sky is not blue. The color blue you see is the reflection of the "water" canopy which surrounds the earth. The sunlight hits the canopy making the sky appear blue.

Sky is blue due to scattering

The blue comes from reflections off the oceans .

Scattering of light is the basic reason for blue sky
since blue ie voilet which has the shortest wavelength of a white light similar to sunlight
which scaters more than the other colour
during day except early morning and late evening the sky appears blue
but in those exceptional condition the sky look red in colour because all the blue scatters away
since red light has a longer wavelength it reaches our eyes
other light scatter away
this is because the distance from earth and sun will be maximum when it is at exteme position

The gases in the atmosphere scatter more of the blue fraction of sunlight than any other wavelength and thus the sky appears blue.

It is supposed to be a mystery but people who deal with science say that its because of particles and oxygen and our eyes just perceive thet the sky is blue

Because someone put a bomb in a bucket of blue pain and it painted the sky blue if your wondering before it was painted it was pink with orange spots

Because we see the short light waves=blue

Why the sky is blue: Summary
The sky is blue because blue light from the sun strikes the air molecules and scatters, and our eyes perceive it as blue.
Why the sky is blue: Short Summary
The blue in sunlight collides with air molecules and our eyes see it as blue.
Why the sky is blue: Condensed
Sunlight collides with air, scatters blue wavelengths.
Why the sky is blue: Ultra-Condensed.
Because it is. Stop asking.

It really isnt. Its pitch black but the sunlight reflecting off outer space makes it appear blue to us

Because there is a sbtince in your fort that makes it blue

The sky looks blue but it really is not

Because of the reflection of the oceans. They take up 3/4 of the planet

Not all time, here's my two simple answers on this.
First, the sky is blue because it is in the day time. The sunlight is more what can you see that governs the appearance of the outer space that came to be a light blue one.
Second, in the night, the sky seems to be dark because the is no sunlight except the moonlight but it seems that the moonlight can lighten the sky as the sun can.

It is due to the raman effect that the sky is blue, that is it is due to the scattering of light and since blue has the least wavelength it get scattered the most

Its not its because when the light hits the road to yours and my eyes the roads black but its really dark blue and the clouds add more white in to the sky which makes it light blue