I was listening to few talks by Dr.Michio Kaku. He said light waves or gravity cannot be used to achieve inter planetary communication but probably by using quantum entanglement two atoms can be made to vibrate in phase and then using atomic transistors one can translate this motion of quantum entanglement to sequence of bits at very high frequency. The interesting nature of quantum entanglement is that it has been experimentally proved and it can possible work over astronomical distances. What does thismean? This means that instantaneous inter planetary communication would be possible. One need not wait for the radio signal to reach a rover on mars and bounce back. Even at the speed of light one single command to move the rover could take about 13 to 20 minutes.