Wireless communication underwater is difficult because water molecules absorb radio waves very efficiently, but a new technique that involves playing garbled acoustic messages backwards could improve wireless communications beneath the waves, according to New Scientist. Broadband powerhouse it isn't: current tests of the system allow them to send data at 15kbps at a range of 4 kilometers, and 5 kilobits per second at 20 km. At 3,500 km the data rate falls to about 100 bits per second.