why is the sky blue?

Answer 1

The sky is blue due to the refraction of light through our atmosphere. It just so happens that the portion of the spectrum that the light is refracted through causes the color blue to be seen. This is a phenomenon known as Rayleigh scattering.

There is a simple way in which we know this is true. As the sun begins to set you can see a progression of the colors of the prism from blue to red.

As a side note which goes along with this, years in which there are more volcanic eruption (IE more gas and particulates in the atmosphere) there are more beautiful sunsets.

Answer 2

Basically, air molecules scatter blue light. An optical phenomenon called "Rayleigh scattering" is generally regarded to be the culprit. Extremely small particles (in this case, the nitrogen, oxygen, etc. in atmosphere) can scatter light of different wavelengths. Although the scattering is in all directions (with some variation), it is strongly dependent on wavelength, so in the case of our atmosphere, only the wavelengths corresponding to blue get scattered and the other colors pass on. So when you look up in the sky, what you're seeing is sunlight passing through the upper atmosphere, but only the bluish wavelengths that happen to bounce off of air molecules and get reflected down at you.

It also explains red light you see from sunrises and sunsets. In this case, light is coming from the sun at a low angle through the atmosphere, and the scattering effectively filters the blue light out, so only the longer wavelengths (the reds and yellows) are left for you to see.

You can find a much better explanation here:

http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html

Answer 3

Because the stars don't ever stay for breakfast......Without Einsteiniums and Avogadro Army technical mumbo jumbo - oxygen /nitrogen/blue light scatters more readily ...cold and unfun answers...The think-tankers response would be " Because someone who lived a long long time ago, picked the word "blue" for the color that you were taught ( in modern culture) to represent blue. Hence the daylight sky actually exhibits, to the color receptors of those who look up, mouthbreathing..., characteristics of the lower wavelengths of the visible light spectrum which are more readily abundant due to ....yada yada yada.. the Question that the Eagles would ask is,..."Why is the clear day sky (no arctic circle wiseacres please) NOT visibly Maroon or for that matter.."Violet"...? you'll find that answer in...Einstein....circa 1911 or some such........BUT...my hypothesis, though not widely accepted and off the beaten path by parsecs, is that " and then like it fell outta the clear, mauve sky" just don't sound good.....have fun and always seek to understand.....laughter...is the best medicine...peace out

Answer 4

Thank goodness everyone asks why is the sky blue and no one asks the much harder question of why is the sky bright.

The Short Answer.

The molecules which make up 99% of the earth's atmosphere do not absorb any wavelengths of visible light. Molecules in the air are not like indigo molecules which absorb red light and give blue cloth its color. Molecules in the air are not pigments. However, molecules in the air do scatter blue light more strongly than red light. This means that white sunlight has its blue components scattered to the side while its red components keep traveling straight. White sunlight bathes the atmosphere of the earth. The sky is blue because molecules in the air scatter blue to your eyes more than they scatter red.

Answer 5

The sky is blue due to the fact that the molecules which comprise our atmosphere reflect back blue light more strongly than other colors of the spectrum.

Answer 6

Rayleigh scattering of light off water droplets in the atmosphere. Blue light is scattered more than red light, so the red/yellow light from the sun gets straight through, and the blue light is scattered all over the place - so the sun looks red/yellow and the sky looks blue.

It is NOT from reflection off the ocean.

Answer 7

The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths. 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.

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.

Why is the sky blue instead of violet?
Because of the strong wavelength dependence (inverse fourth power) of light scattering according to Raleigh's Law, one would expect that the sky would appear more violet than blue, the former having a shorter wavelength than the latter. There is a simple physiological explanation for this apparent conundrum. Simply put, the human eye cannot detect violet light in presence of light with longer wavelengths. There is a reason for this. It turns out that the human eye's high resolution color-detection system is made of proteins and chromophores (which together make up photoreceptor cells or "Cone" structures in the eye's fovea) that are sensitive to different wavelengths in the visible spectrum (400 nm–700 nm). In fact, there are three major protein-chromophore sensors that have peak sensitivities to yellowish-green (564 nm), bluish-green (534 nm), and blue-violet (420 nm) light. The brain uses the different responses of these chromophores to interpret the spectrum of the light that reaches the retina.

When one experimentally plots the sensitivity curves for the three color sensors (identified here as long (L), middle (M), and short (S) wavelength), three roughly "bell-curve" distributions are seen to overlap one another and cover the visible spectrum. We depend on this overlap for color sensing to detect the entire spectrum of visible light. For example, monochromatic violet light at 400 nm mostly stimulates the S receptors, but also slightly stimulates the L and M receptors, with the L receptor having the stronger response. This combination of stimuli is interpreted by the brain as violet. Monochromatic blue light, on the other hand, stimulates the M receptor more than the L receptor. Skylight is not monochromatic; it contains a mixture of light covering much of the spectrum. The combination of strong violet light with weaker blue and even weaker green and yellow strongly stimulates the S receptor, and stimulates the M receptor more than the L receptor. As a result, this mixture of wavelengths is perceived by the brain as blue rather than violet.

You could get more information from the link below...

Answer 8

Nitrogen. The atmosphere is approx 78% Nitrogen and Nitrogen absorbes all but blue so blue is reflected therefore the sky is blue.

Answer 9

mixture of space blue (really dark) and sun. seems blue but its actually darker than what it looks, kind of at night, that is the real color, the blue in the mornings, its faded by the sun.
and if what you wanna hear is something stupid... well the sky is a mirror and reflects the sea... coooool!!! or the whater went up there, and it cant go down.

Answer 10

you would need to know information on light and the Earth's atmosphere to understand why the sky is blue.