Why Is The Sky Blue?

Question

Anyone care to give me a REAL, scientific answer?

Answer 1

I painted it and put the twinkling stars to shine like I did it with your eyes.

Answer 2

The sky doesn't have any color to it and it only appears to be blue on a sunny day, on a dull day it's grey and at night it's black, at times of sunrise and sunset it can be many shades of red, orange, yellow and in some cases even green.

The light that leaves the sun, like any light, consists of all the colours of the spectrum (red, orange, yellow, green, blue, indigo and violet) and when these colors mix they make white light. Each of these different colors has a different wavelength - a beam of light is actually a series of waves, very very small waves.

Our atmosphere is made up of countless molecules and atoms such as those of nitrogen, carbon dioxide and oxygen. The size of these minute particles is in some cases, larger than, smaller than or the same size as the wavelength of the different colors of the spectrum. The result is that the light with the longer wavelengths passes the particles without being affected but the light with the shorter wavelengths are absorbed by and knocked off course by the atmospheric particles. This is something that is known as Rayleigh Scattering.

So... some of the colors that make up white light reach earth unaffected but other colors (blue, indigo and violet) are scattered about in all directions and it's this scattering and absorption of the light at the blue end of the spectrum that makes the sky appear to be blue.

If the particles in the atmosphere were a different size or the wavelengths of the colors were different then we could see the sky as being red, or green or black or in fact, any color. It's only the mix of colors that reaches us that combine to give the sky a blue appearance.

What happens in an evening when the sun sets is that the sun sits low on the horizin and the angle of the sunlight has to pass through more of earth's atmosphere, because it passes through more atmosphere more of the light is absorbed and scattered and only the light at the red end of the spectrum is able to get through unaffected - this is why sunsets are red and orange.

If there were no atmosphere the sky would appear to be black even in the middle of the day. If you look at any of the photos taken on the moon (where there is no atmosphere) you can see the pictures are taken in bright sunlight but the sky is black. The sky isn't dark it's black - there's a difference. You could paint the walls floor and ceiling of a room in black and no matter how much light there was in the room everything would still be black.

For more technical info including diagrams check these sites...
http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html
http://en.wikipedia.org/wiki/Rayleigh_scattering
http://www.philiplaven.com/p8b.html

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.

The atmosphere around the Earth is largely made up of two colorless gases: oxygen and nitrogen. Red and blue light reacts very different from each other to oxygen. Because the wavelength of blue light is roughly the size of an atom of oxygen, blue light interacts with the oxygen and is scattered by it, while red light, with its longer wavelength, goes right pass the oxygen atoms. If the Earth had no atmosphere, the sun’s light would travel directly from the Sun in a straight line towards our eyes and we would see the Sun as a very bright star in sea of blackness. But because the Sun’s blue light is scattered by the oxygen in the atmosphere, blue light from the Sun enters our eyes from all sorts of different angles and we see the entire sky as blue. The atmosphere scatters violet light even more effectively, but our eyes are more sensitive to blue. Wherever we look towards the sky, some light is bouncing off an oxygen atom and entering our eyes, making the sky appear to be blue.
Sunrise, Sunset

Who hasn’t enjoyed watching a sunset as the Sun’s red disk sinks below the horizon. Why does the Sun now appear red? During sunrise and sunset, the Sun’s light must pass a greater distance through the atmosphere in order to reach our eyes because instead of dropping directly through the atmosphere, it reaches the Earth at an angle. The same scattering effect on the blue light, also takes place, but the blue light is unable to pass through the extra distance and reach our eyes. This leaves only the red light which passes, unhindered through the atmosphere and reaches our eyes in a direct line with little or no scattering. We see the Sun’s disk red because its blue light has been blocked by the atmosphere. We don’t see the entire sky red because there is no scattering and the red light reaches us in a direct line.

Answer 4

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.

Answer 5

Why is the sky blue?

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.

Answer 6

In addition to the mixture of the gases Nitrogen, Oxygen, Neon, Argon, Xenon & Krypton. The particles in the air reflect blue light. When the sun goes down there is nothing for the air particles to reflect so we see a black sky.

Answer 7

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

in simple words we have an atmosphere(a medium), suns rays experience refraction, hence the one with shortest wavelength, violet is scattered by the particles in the medium, but since our eyes are more sensitive to blue than violet,it appears blue.

Answer 9

ok here's the scoop, the sky has many different gases in it, to be frank, and when those certain gases combine they just happen to make a blue color.

Answer 10

space is dark blue so the sky is light blue?