why is the sky blue?

Answer 1

Light is an electromagnetic wave. If you stand in one spot as a light wave passes by, there will be an oscillating electric field and an oscillating magnetic field, which are perpendicular to each other. If the light is in the range of frequencies that we can see, then the frequency of the vibration affects the color of the light. The color-vision receptors in our eyes, the cones, are of three types: "blue" receptors that respond to light over a broad range of high frequencies, "green" receptors that respond to medium frequencies, and "red" receptors that respond to low frequencies. The ranges of sensitivity of the receptors overlap considerably, but they have their maximum sensitivities at different frequencies. The perceived color depends (among other things) on the relative strengths of the signals from these receptors.
Molecules are usually electrically neutral, but they are made of charged objects: their atoms consist of negatively charged electrons and positively charged nuclei. If there is an electric field at the position of an atom, the nucleus will move a short distance in the direction of the field and the electrons will move the other way, and the atom will become a "dipole": the positive and negative charge will be centered around different places. A molecule made of such atoms will acquire its own electric field, something like the magnetic field of a bar magnet.
A dipole's electric field falls off more rapidly with distance than it would if the molecule had a net electric charge. This is because at large distances, the fields from the positive and the negative charge tend to cancel each other out, as the difference between their average positions becomes less important.
However, if the dipole is made to oscillate-- that is, if the positive and negative charge wiggle back and forth, out of phase with each other-- then the molecule can produce electromagnetic radiation of its own. This is how air molecules scatter light: the oscillating electric field of the incoming wave makes the molecules develop oscillating dipoles, which in turn give off radiation.
The radiation destructively interferes with the incoming wave in the forward direction. The original wave is lessened in intensity, and new waves move out in all other directions, so that overall energy is conserved (this requirement is sometimes called the "optical theorem"). The net effect is that light energy that was moving in a straight line from the sun ends up traveling in some other direction.
Since sunlight appears white but the sky is a robin's-egg blue, it must be that the scattered light excites our blue-sensing cones more, and our red-sensing cones less, than the original sunlight. The distribution of frequencies in the scattered light must be biased toward high frequencies.

Answer 2

I thought it would be a pretty color for the sky to be and the one that made the most sense. Just kidding.
Actually, rowife and Alice have the best answers. It is an illusion. The light from the sun passes throught the air, the atmosphere, and from where we are, we see the color that is commonly called blue according to the accurate scientific description provided by rowife and Alice.

Answer 3

The sky is not blue. The sky is black with the absence of light. The light passing through the air is less blocked by that color, so blue more than any color of the spectrum from the sun gets through to your eye. The color of the spectrum our eye responds to, we have named "blue."

Answer 4

The sky is not blue. It just looks blue. I can't even remember the scientific explanation.

Answer 5

Because molecules in the air scatter blue light from the sun more than they scatter red on a clear clouldless day.

Answer 6

check resolved qeustions. This question has been aked a million timse.

Answer 7

Sun light reflects off the contents of the atmoshere as that color.

Answer 8

To make us happy.

Answer 9

terraforming

Answer 10

because you accept that it is....