In the far future, humans might communicate across great interstellar distances—light years, in fact—using an immense intergalactic communications array powered by the Sun.
Such an array would "live" about 550 astronomical units from the Sun at a point in space where light rays bent by gravitational lensing converge. At this point, the array would serve as a magnifier for any signal we'd like to send to faraway worlds or systems (Alpha Centauri, perhaps).
This magnification effect would be especially important to future human space exploration missions that happen to travel beyond our solar system. Beyond Voyager-type distances, 10 billion kilometers or more, radio signals become garbled or lost thanks to the cosmic microwave background radiation that we believe is an echo from the birth of the Universe.
Indeed, many scientists today believe one of the major reasons we have yet to hear from alien life may be due to the fact that this background "noise" is drowning everything out. This array would help address that "deafness" and boost (or intercept) signals.
The tricky part would be the receiving array. Not only would we have to put a lens at 550 AU from our Sun, we'd have to do the same in the system we're attempting to talk to as well. For our nearest neighbour, Alpha Centauri, that would be 4.37 light-years away, and then 749 AU from Alpha Centauri itself in that system's sweet spot.
That's amazing, currently unfathomable distance, of course, but if one gets past that minor detail, the technology driving the array is actually quite spartan, reports Space.com:
With these relays in place, the error rate between the two points would drop from 1-in-2 to 1-in-2 million on par with the accuracy achieved by the DSN in our local solar environment.
Shockingly little transmitting power is needed, too: just one-tenth of a milliwatt, or several orders of magnitude less than the DSN's antennas, Maccone found.
Distance is the major hurdle people think of when it comes to hypothesizing about human space travel outside the solar system. Communications, however, will be equally daunting. A system like this one, while still bound by the laws of physics and the speed of light, would at least ensure the messages are crystal clear when they hit astronauts' ears 4.37 years after initial transmission. [MSNBC]