why is the sky blue?

Answer 1

The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths and also because of density fluctuations in the moving air (see below). Combined, these effects scatter (bend away in all directions) some short, blue light waves while allowing almost all longer, red light waves to pass straight through. When we look toward a part of the sky not near the sun, the blue color we see is blue light waves scattered down toward us from the white sunlight passing through the air overhead. Near sunrise and sunset, most of the light we see comes in nearly tangent to the Earth's surface, so that the light's path through the atmosphere is so long that much of the blue and even yellow light is scattered out, leaving the sun rays and the clouds it illuminates red, at sunrise and sunset.

Scattering and absorption are major causes of the attenuation of radiation by the atmosphere. Scattering varies as a function of the ratio of the particle diameter to the wavelength of the radiation. When this ratio is less than about one-tenth, Rayleigh scattering occurs in which the scattering coefficient varies inversely as the fourth power of the wavelength. At larger values of the ratio of particle diameter to wavelength, the scattering varies in a complex fashion described, for spherical particles, by the Mie theory; at a ratio of the order of 10, the laws of geometric optics begin to apply.

Individual gas molecules are too small to scatter light effectively. However, in a gas, the molecules move more or less independently of each-other, unlike in liquids and solids where the density is determined the molecule's sizes. So the densities of gases, such as pure air, are subject to statistical fluctuations. Significant fluctuations are much more common on a small scale. It is mainly these density fluctuations on a small (tens of nanometers) scale that cause the sky to be blue.

Answer 2

Einstein answered this question. It has to do with the way sunlight is scattered by the molecules in the atmosphere. Blue light scatters more than red (Tyndall effect also known as Rayleigh scattering), so more blue light reaches our eye.

There is an excellent description at the website listed below (look at the cartoon and it will be pretty clear).

It is not a reflection from the ocean. And it isn't just water molecules that cause the effect.

Aloha

Answer 3

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.

As you look closer to the horizon, the sky appears much paler in color. 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 color of the sky near the horizon appears paler or white.

Answer 4

it's due to the atmosphere. the blue colour from the white light can been blocked by the atmosphere and the blue 'stained' on it, so the sky looked blue. this is why the light rays on the earth is not very white. the red and violet lights cannot be block so we called it ultraviolet and ultrared.

Answer 5

no idea why the sky is blue but i do know that during sunsets, the reason why the sky is so beautiful is because of the pollution in our atmosphere...kinda sad, huh?

Answer 6

The color of the sky is blue because the atmosphere scatters shorter wavelenght light (blue and violet) more than longer wavelength light (red), and thus we see more of the scattered blue light.

Answer 7

http://www.answers.com/RAYLEIGH%20SCATTERING


Rayleigh scattering (named after Lord Rayleigh) is the scattering of light, or other electromagnetic radiation, by particles much smaller than the wavelength of the light. It occurs when light travels in transparent solids and liquids, but is most prominently seen in gases. Rayleigh scattering of sunlight by the atmosphere is the main reason light from the sky is blue.

Answer 8

the sky is blue because most of the earth's atmosphere is made up of nitrogen and this concentration of nitrogen is responsible for the blue color

Answer 9

blue is the sapphire and sea
sparkling shafts waving free
blue are the eyes looking at me
reflecting a song back to u...

actually maybe its something to do with chemicals and reflectors and moisture levels in the atmosphere...hmmm?

Answer 10

if the sky wont be blue, it will be in grey, or in red. other than that, is "armegeddon" !!! OMG,