WHY IS THE SKY BLUE??? anyone know?

Answer 1

The first thing to recognize is that the sun is an extremely bright source of light -- much brighter than the moon. The second thing to recognize is that the atoms of nitrogen and oxygen in the atmosphere have an effect on the sunlight that passes through them.

There is a physical phenomenon called Rayleigh scattering that causes light to scatter when it passes through particles that have a diameter one-tenth that of the wavelength (color) of the light. Sunlight is made up of all different colors of light, but because of the elements in the atmosphere the color blue is scattered much more efficiently than the other colors.

So when you look at the sky on a clear day, you can see the sun as a bright disk. The blueness you see everywhere else is all of the atoms in the atmosphere scattering blue light toward you. (Because red light, yellow light, green light and the other colors aren't scattered nearly as well, you see the sky as blue.)

Answer 2

This question has been asked over 4000 times, and here is my standard answer to this often-asked question, without using too much physics:

The correct answer is that the blue light is scattered by the air molecules in the atmosphere (referred to as Rayleigh scattering). The blue wavelength is scattered more, because the scatteing effect increases with the inverse of the fourth power of the incident wavelength.

OK, but I've known science graduates who don't understand what this means.
Here's my attempt at an answer without too much physics:

I think most people know that sunlight is made up of light of several different wavelengths, and can be split up into the colours of the rainbow. Blue light has the shorter wavelength, and red the longest wavelength.

When sunlight hits the molecules in the atmosphere, the light strikes the molecules and is absorbed, causing the molecules to vibrate and give off, or 're-emit' the light. It's not the same as reflection, but the effect is similar. The molecules in the air are much smaller than the wavelength of visible light, but because the blue wavelength is shorter and more energetic, it reacts much more with the air molecules than the red and yellow wavelengths; which tend to pass straight through.

Because the blue radiation is re-emitted from the air molecules in all directions ('scattered'), it seems to us looking from the ground that the blue light is coming from everywhere; hence the sky seems blue.

Near sunset, because of the low angle of the sunlight, we see more of the red and yellow wavelendth passing straight through, hence the colours of the setting sun.

BTW: The sky isn't blue because of a reflection of the sea; its the other way round, although the blue colour of the sea is mostly caused by the water molecules scattering the blue light, in a similar way. This effect is even stronger with ice; which results in the intense blue colour we see if we look down a crevasse in a glacier, or down a hole in the snow made by a ski stock..

For a complete, scientific explanation, look up 'blue sky' in Wikipedia.

Answer 3

Ok the answer has been written so often now but I can't resist adding my voice, I mean keyboard sounds. The sky appears blue because of the Rayleigh effect. Light is scattered by nitrogen molecules as it enters the earth's atmosphere. It so happens that the blue section of the visible spectrum is scattered more than the rest and consequently you see alot of blue.

Answer 4

We see the sky as blue because of something called the Rayleigh effect. As light passes through a gas (in this case air) it is absorbed and re-radiated by the gas molecules. The effect varies according to the wavelength of the light. Red light (long wavelength) tends to pass straight through, Blue light is absorbed and re-radiated and gets scattered all around. It is this scattering effect that makes the sky look blue.

Answer 5

Good morning!

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.

NASA's website has a good explanation: http://spaceplace.nasa.gov/en/kids/misrsky/misr_sky.shtml

You can also check out more info here, on the How Stuff Works website: http://science.howstuffworks.com/question39.htm

Hope that helps!
~Julie
Baltimore County Public Library

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Answer 6

Yes. Fluctuation Scattering.

Answer 7

It has something to do with the ocean reflecting on the ozone i believe or the outer blanket on earth making the sky appear to be blue.

Answer 8

It has to do with Rayleigh scattering and the bonding angle of nitrogen atoms in the atmosphere. Nitrogen tends to scatter light in the blue portion of the spectrum.

Doug

Answer 9

If you type the details into the 'search for questions' box , you'll get the answer. I've seen this question asked several times before.

Answer 10

its nature that the color of sky is blue.. God given color..