why is the sky blue?

Answer 1

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 2

When you look at the sky at night, it is black, with the stars and the moon forming points of light on that black background. So why is it that, during the day, the sky does not remain black with the sun acting as another point of light? Why does the daytime sky turn a bright blue and the stars disappear?

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.)

More info:
http://www.glenbrook.k12.il.us/gbssci/phys/Class/light/u12l2f.html

Answer 3

Transmitted light (from the sun, light bulbs, fire, etc) is made up of a spectrum of colors. The longest wavelengths of light are on the red end of the spectrum and the shortest wavelengths are on the blue/violet end of the spectrum.


When transmitted light such as sunlight enters our atmosphere it collides with the oxygen and nitrogen atoms. The color with the shorter wavelength is scattered more by this collision. Because violet and blue are the shortest wavelengths the sky appears to be violet / blue. But because our eyes are more sensitive to blue light than they are violet light, we perceive the sky as blue.

Our eyes contain thousand of rods and cones, which are the receptors for light. Whenever one of the 3 Stooges pokes you in the eye you see a giant blue spot. This is because the blue receptors have been activated. Blue is one of the primary colors and thus more easily activated and seen by our eyes.

Blue is also how I feel when my baby leaves and my hound dog dies. Also, how I feel when the cops pull me over and I see their blue lights flashing in my rear view mirror. Then, again, blue is the color of the K-mart special, so this color isn't all bad.

Answer 4

We owe some of our most spectacular atmospheric phenomena to various types of scattering: the blue of the sky, the red of the sunset, the white of clouds and, that epitome of rare occurrences, the blue moon. Most blue and green bird-feather colors involve scattering, as do many animal and some vegetable blues.


Why isn't the sky black?
Our sky is colored because our atmosphere makes blue light when sunlight passes through it. This phenomenon is called "scattering." It is similar to when sunbeams reveal themselves in the presence of dust, most spectacularly in cathedrals. The atmosphere causes the sky to be colored.





Moonrise with blue scattering caused by earth's atmosphere, photographed from the orbit of Space Shuttle Discovery in 1999.

Earthrise with black sky since there is no atmosphere, photographed from the orbit of Apollo 11 in 1969.




If there were no atmosphere, the sky would appear black, like the lunar sky in Apollo pictures taken from the moon. But even a black sky has some lightness... Even at night, the sky always has a faint color, called "skyglow" by astronomers. Atmospheres also cause skyglow from faint airglow in the upper atmosphere (a permanent, low-grade aurora), and starlight scattered in the atmosphere. Even if there were no atmosphere, faint skyglow is caused by sunlight reflected off interplanetary dust (zodiacal light), and background light from faint, unresolved stars and nebulosity.

Answer 5

The light from the sun is refracted and scattered by the gas molecules in the atmosphere. The relatively longer wavelengths of the blue end of the spectrum are not absorbed by the molecules in the atmosphere and so they pass to our eyes.

Answer 6

because the most common gas in our atmosphere is nitrogen which appears blue when it filters the sunlight reaching our eyes. different gasses would cause a different color atmosphere over our heads

Answer 7

Because of the way the water in the atmosphere bends light.

Answer 8

Because the atmosphere is blue.

Answer 9

God made the sky blue thats why

Answer 10

light hits the Earth's atmosphere and is refracted to change colors due to the change in speed.