IMPOSSIBLE! Preposterous! These words are often thrown about when people declare certain things to be scientifically ridiculous. Aliens cannot reach the Earth in spaceships, they proclaim, because the distance between stars is too great. Telepathy is impossible since the brain does not emit or receive messages. And it’s impossible to instantaneously transport an object from A to B because you cannot know the location and momentum of all its atoms — teleportation would violate the Heisenberg uncertainty principle.
Yet if you carefully analyze these examples, you realize that they are merely impossible today or in the near future. The real question is, are they impossible with technologies that lie decades, centuries or even millennia beyond ours? Perhaps these ‘impossibilities’ are merely very difficult engineering problems. The late Arthur C. Clarke once said, “Any sufficiently advanced technology is indistinguishable from magic.”