Science Profiles Keeping track of breakthroughs in science…

Talk About ‘Far Out!’

"FINDING ALIEN MESSAGES... Two University of Hawaii physicists say the reason we're not getting messages or signals from alien civilizations is that such communication is disguised and indistinguishable from background noise. Walter Simmons and Sandip Pakvasa say messages sent by this method could be criss-crossing our galaxy without us ever knowing. If a signal -- a stream of photons -- comes from a single source, its origin can always be determined by measuring the direction of recoil of a detector struck by the photons. The physicists say the way around this is the signaler splits the message into two parts, so photons are sent in opposite directions to mirrors located far from the home planet. The mirrors redirect the signals to the intended receiver, who recombines the photons to reconstruct the message. If the image is tiny enough, Heisenberg's uncertainty principle -- which limits the amount of information that can ever be known about a microscopic particle -- means measuring the position of the photons makes it impossible to gain accurate information about the direction in which they are traveling. It also would be impossible to detect the message at all without extremely sophisticated technology. To recombine the beams and recreate the message you would need to detect the arrival time of the photons extremely accurately to identify pairs of photons split by the sender."