Our atmosphere likes equilibrium and dislikes differences is pressure. So when low pressure develops, air pours in to fill it. It's just like pulling the plug out of a bathtub full of water. The water from the tub rushes in to fill the hole in the drain. You might think the water is pulled down by gravity, but if the drain were already full of water, the water in the tub would stay put.
The colors in order of discovery were blue (Mercury), white (Co2), gold (Helium), red (Neon), and then different colors from phosphor-coated tubes. The mercury spectrum is rich in ultraviolet light which in turn excites a phosphor coating on the inside of the tube to glow.
Neon refers to the ability of absorbing, redirecting and controlling Neon light. This ability is first demonstrated in InFamous: Second Son by Abigail Walker and eventually absorbed by Delsin Rowe.