Gases in the sky are not blue themselves. The blue color we see in the sky is caused by a phenomenon called Rayleigh scattering.

Here's how it works:

* Sunlight: Sunlight is made up of all colors of the rainbow.

* Scattering: When sunlight enters the Earth's atmosphere, it interacts with tiny particles like nitrogen and oxygen molecules.

* Blue Wavelengths: Blue wavelengths of light are shorter and scatter more easily than other colors. This scattering happens in all directions.

* Our Perception: As we look up at the sky, we see the scattered blue light coming from all directions, giving the appearance of a blue sky.

Therefore, the gases themselves aren't blue, but the way they interact with sunlight creates the blue color we perceive.