Why is the sky blue?

We see sunlight as white light, but it is actually a mixture of
red, yellow, orange, green, purple, and blue. When the sun's
light passes through the earth's atmosphere, these individual
colors are deflected and scattered in many different ways by
atmospheric molecules and other stuff in the air.

The colors blue and purple are deflected the most, which causes
these colors to scatter all over the sky. Since the human eye
can detect blue easier than the color purple, humans see the
color blue whent they look up into the sky.

I wonder what color dogs see?