Is the sky?

Question

really blue, or does it just look like it

Answer 1

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 2

Light from the Sun (white light) is made up of many colours - red, green, blue,
and so on. Each of these colours has a different wavelength and frequency. When
light reaches the atmosphere it hits gas molecules which scatter the light in
all directions. This scattering is called Rayleigh scattering after Lord
Rayleigh who worked out the mathematical equations to describe it.

So how does Rayleigh scattering work? Rayleigh scattering only happens when the
molecules of gas encountered by the light waves are small compared to the
wavelength of the light. What’s strange about Rayleigh scattering is that not
all of the light is scattered evenly. Some wavelengths are scattered more. With
white light, mostly the light of shorter wavelengths (the blue end of the
visible range) is scattered whilst the longer wavelengths (the red end) are
mostly uneffected. This means the blue light is scattered more than the red.

But violet light has the shortest wavelength so why isn’t the sky violet? Well
it’s true that the violet light is scattered more than the blue light, but our
eyes aren’t so good at picking up violet light. This means we see the sky as
being blue even though there is some violet light there too.

Answer 3

Nothing is really blue, it just looks like it.

When you see the color blue what you are actually seeing is all the colors that were not absorbed by the object. So when you see blue water you see all the light reflected from it except for the blue light. That light is absorbed so you see it as blue.

With the sky the same thing happens the light that passes through it gets absorbed. A lot still gets through, but not all of it does. This is good because some of that light is strong enough to hurt us. This is what people are talking about when they talk about radiation, or ultraviolet radiation (UV). Just as the atmosphere absorbs some of the ultraviolet that reaches us it absorbs the color blue.

So yes the sky is really blue.

Answer 4

It just looks like it...

The sky is what we call the appearance of a hemisphere over our heads. On a clear day it appears blue. The deepness of the blue increases as we move from the horizon to the point above our head.

The sky is blue because of Raleigh scattering. Raleigh scattering defines the amount of scattering of light rays. Since all colours of the rainbow create a white light we should see a white sky, but blue light scatters much more than red. That is why the sky appears blue (on a cloudless day).

On a cloudy day, it appears to be grey.

Answer 5

Air is transparent. It has no colour.

The 'sky' is blue. Here, sky means a sufficiently large volume of air exposed to illumination by the sun.

While the sun is shining (above the clouds) and we see clear air to a sufficient height, then all we will actually see is blue colour. This is the blue part of the sunlight scattered to our eyes by Raleigh scattering.

The light source needs to be sufficient strong though - otherwise the scattering will not be significant and the air will just be transparent.

At night, when the sun does not shine, the sky again returns to its true transparent 'colour' - that's why we can see the true colour of moon, stars & planets.

Answer 6

The sky isn't really blue, but what makes the sky blue is the reflection of sunlight off of water, like in the ocean.

Answer 7

The Sky is Not an Object, you are Looking through the Atmosphere. As Blue is a Color, and Color is Visual....It Looks like it.
For why, See Links:

Answer 8

The atmosphere reflects light in blue part of the spectrum of visible light, which makes it appear blue. That's what makes things different colors-different objects reflecting a different part of the spectrum of visible light.

Whether it is "really" blue is a philosphical question.

Answer 9

To your eyes its blue thats the only spectrum that comes through. The magnetic field ozone ect affect what light rays can come through.

We see blue during the day, at sunset it can go red. Mars is 100% opposite its red during the day but at sunset it can go blue.

Answer 10

in acuallity the sky is purple, but the way the light reflects in our eyes makes it seem blue.