why is the sky blue?

Answer 1

because it is

Answer 2

This gets asked loads and answered, usually, badly. Rayleigh scattering often gets mentioned. What does that tell you ? You might learn two new words "Rayleigh" and "scattering" but what else ? Does it explain why different coloured light is scatters differently ?

If you want to know what really happens .....

Forget the atmosphere for a moment, just imagine a single electron and a red photon (which has little energy) and a blue photon (which has a lot).
The blue photon has nearly enough energy to lift the electron to a higher energy state, but it doesn't have quite enough so it borrows the extra energy from nothing at all (really, energy is borrowed from nothing !!!). But, Mother natures rule for borrowing energy is "the more you borrow the sooner you have to give it back". So now we have an electron in a high energy state held there by the energy from the blue photon and the borrowed energy. Because only a little bit of energy was borrowed (remember the rule) it can stay in this state for quite a long time before mother nature asks for her energy back. When that happens the blue photon is "kicked back out" of the electron.
The key point is that the electron is part of an atom (say a Nitrogen atom in the atmosphere) and that atom is spinning so it can turn quite a long way in the time between when the blue photon was absorbed and emitted. The practical upshot of which is that the blue photon approaches the atom from one direction but departs in a very different direction or is "scattered". So all blue light is scattered from all Nitrogen atoms in the atmosphere all around so the sky appears blue. Voila !

A red photon (less energy) to boost an electron to a higher level has to borrow a lot of energy and so has to pay it back sooner. That means the atom won't have turned very far before the red photon is fired out again. So its fired out in pretty much the same direction as it arrived.

Its a bit like jumping on a a merry-go-round. If you stay on for a few seconds, when jump off you'll be travelling in a completely different direction. If you jump on then straight off you'll be travelling in pretty much the same direction as when you jumped on.

Answer 3

Sorry but I firstly need to tell you that your qestion needs rephrasing. The sky is not blue. It just appears blue. Now I'll explain:
When light rays coming from the sun, travelling in a vacuum which space is, arrives near our earth, they are refracted since they are no more in vacuum but have entered the ionosphere. So as they are refracted the different components of light are made to deviate so as the colour that deviates by the largest amount is seen. And that colour is blue. Since the other colours can recombine more easily as they are nearer, they recombine. Thus we do not notice red, orange , yellow etc. In fact the sky is not a constsnt blue as we can notice that at different light intensity of the day, the blue colour of the sky appears darker sometimes. Thats because the last three colours of the light which are blue, indigo and violet are nearly the same - all have blue in them. SO blue predominantly is seen. But as light intensity changes, you can see that the blue colour either deepens or becomes less blue.

Answer 4

The sky is actually black, but as the sun rays descend to Earth they hit certain layers of the athmosphere, like the ionosphere, layers that give the sky its blue colour. As a matter a fact we can only see the sky at night, because during the day what we see is the light of the sun reflecting on the surface of the planet. Its like putting thousands of lasers on a wall, u can only see the wall after the lasers stop. Buh bye

Answer 5

Light from the sun is scattered by the atmosphere according to wavelength. The shorter the wavelength the more it is scattered. Blue light is scattered more that red or yellow light because the wavelength of blue light is shorter.

Answer 6

Blue light waves are easier to scatter than the other waves of the visible spectrum.

Answer 7

blue is the dominant color in the visible light spectrum

Answer 8

blue is the dominant refractor component in light

Answer 9

Because it reflects the sea........why is the sea blue?...... cos it reflects the sky.........oooooohhhhhhh my head is going to explode!!!!!!!!

Answer 10

Stop asking this question!

Answer 11

Because you touch yourself at night.