"It does. Air has substance, it's just incredibly thin compared to liquids or solids. Think about it: if there wasn't anything in air, you wouldn't need to breathe."

His fingers slide up into Zane's hair briefly, then withdraw, and he rests his arm on the back of the couch.

"You don't feel it because barring extraordinary circumstances, the pressure is very nearly the same everywhere on the surface of a given planet. The particles in air all always moving a little bit, and they move more from high pressure to low pressure, which keeps them evenly spread out."