The colour of the sky is the same colour as our neighbouring Planet Mars;
RED . The redness is more visible at sunrise and sunset.
The blueness came about 200 million years ago when a planetary body impacted the Earth, fragmenting it into today's continents and islands. Particles from the earth were thrown upwards into the atmosphere creating the blueness that we see today, out of the existing redness.

During sunset, due to the sky's curvature, the sun's rays are striking the lower part of the sky that is particle-free.

How cool is that? Maybe Terry should rename this section..."Why was the sky red?"

Good Idea, how about Why the Sky isn't blue?

You have got it all mixed up ...

Ok, someone asked this question before so I will just copy my answer here from the previous thread - "the atmosphere is largely made up of Oxygen and Nitrogen. 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 (hence blue sky). Red having a longer wavelength goes right pass the O2 atoms. Actually the atmosphere scatters violet light even more effectively, but our eyes are more sensitive to blue. So basically, when you look towards the sky, light is bouncing off an oxygen atom and entering our eyes, making the sky appear to be blue."

Now we come to the sunset part - 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. We have the same scattering effect - the difference is that the blue light is unable to pass through the extra distance and reach our eyes. The red light does pass and reaches our eyes in a direct line with little or no scattering - the blue light has been blocked by the atmosphere. The entire sky does not appear red because there is no scattering and the red light reaches us in a direct line.

It is wrong to compare Mars and Earth. On Mars red is due to red rusted iron dust particles in its atmosphere, as well as soil of the planet. It has a much thinner atmosphere and scattered light is much less of a factor there than here.

And of course, last but not least - how the continents were made in the first place - someone missed a few classes in school it would seem - continental drift and tectonic plates is the answer. Proposed in 1912 by Alfred Wegener, a German meteorologist then added to it the research by Arthur Holmes, Scottish geologist in 1928 (though now modified from his original concept of fluid movement into rock movement). Later on we finally had a synthesis of that and the work in the 60s, some heavy testing of the whole thing and now, accepted by practically everyone, the plate tectonic theory.

The visible electromagnetic wavelength is due to the random deviation of light particles in photons. and thats why the sky is blue!!!

Because blue is the most popular colour in the world. If he most popular colour had been gren, the sky would have been green. It is afte all, the thing you see the most of, when you're not staring into the computer screen at the FT forums.

I have heard various guess's of the sky being blue, due to the color of the sea. Gee, I didn't think that would be true. The sky isn't green blue! Besides, as new names for this post, it should be "Why is the ozone layer blue?". There isn't a sky.