While we cannot actually see them, the airwaves are crammed with transmitted frequencies that are projected across the ionosphere each second.
在我們頭頂上的天空中，每分每秒都是交通顛峰﹘﹘肉眼看不見的無線電波以各種波長，從各種反射角度，挾帶著各種訊息，飛快地在天地之間穿梭。