[gadilif]

Thanks for the PBS reference, interesting! As to the energy required, well, yes, I guess manipulating huge masses will be costly, but, if there is an efficient way to do this, then gravity waves are a parallel plane of communication. The analogy I heard once is about tribes communicating with smoke signals, while the air around them is filled with radio waves. Maybe we can't hear anyone out there because we're not listening to the right thing...