A better way to transmit messages underwater

RADIO waves cannot penetrate water, so cannot be used for submarine communication. That is why the sea is probed by sonar, not radar. But, as people and their machines venture ever farther into the deep, ways of building underwater communications networks would be welcome. And researchers at Newcastle University, in England, led by Jeff Neasham, think they have just the thing to build them with: an acoustic "nanomodem". Existing underwater modems, which transmit and receive data via sound, are p...