Is there a technical name for that 'bubble'? Like since we've been broadcasting signals out (television and radio etc) and saying they've been expanding at 100

Is there a technical name for that 'bubble'? Like since we've been broadcasting signals out (television and radio etc) and saying they've been expanding at 100% strength in all directions (for the sake of argument) then we have a bubble around us. And even if we time-travelled back into our past and changed everything, nothing beyond that bubble would be changed because nothing we'd ever done previously had gotten that far out.