Why is our Sky Blue?
A big question we sometimes ask our self is why the sky is blue? We may also question why the sky or horizon during the day time is blue even when we know black space is behind it and above it, if we are looking out into space by looking up into the sky then why is the sky blue and not black?
Sunlight of course is made up of all colors you see in a rainbow such as red, orange, yellow, green, blue and violet. But when the sunlight passes through our atmosphere which is full of gases (oxygen and especially nitrogen) the light scatters. Of course sun light doesn't look like a rainbow nor does it look like it contain all the colors of a rainbow but it does, the white light that comes from our Sun is actually a mixture of colors.
When Isaac Newton studied about Light he used a prism to view and separate colors through it, a prism was used to prove that sun light really was several colors and not just one. It was found that the color 'Blue' is the color with shorter light waves when compared to the color red which has longer light waves, so when the sun light reaches our atmosphere and is scattered due to the gas molecules in the air Blue Light Waves are scattered more than the other colors during a clear day and it travels in short but small waves.
Remember that when you look at the sun directly (I don't recommend) you will the bright light the sun gives off, but when you look at the sky but not at the sun and you see the blue sky you are seeing the blue being scattered throughout the sky. You will also notice that when you look lower to the horizon or lower sky the sky is a lighter shade of blue, this is because the light has traveled through more air compared to the light that comes from a higher angle. After the light travels through so much air the molecules have the scattered the blue light so many times that the blue color turned to a much lighter blue and sometimes may even appear white.
A red sky on the other hand is when the light has traveled so much through the atmosphere that it allows the reds and yellows to be seen, the red and yellow light has longer waves and this light becomes seen as soon as the sun is low on the horizon. The sky is red simply because the light has through a thick atmosphere but also because the dust particles and water vapor which hang in the air allow the color red to scatter, this means many other colors are also able to scatter.