The thing that gets under my skin about arguments over the Fermi paradox is that everyone ignores the initial context that generated it. > Teller writes that h

The thing that gets under my skin about arguments over the Fermi paradox is that everyone ignores the initial context that generated it. > Teller writes that he thinks Fermi directed the question to him: "How probable is it that within the next ten years we shall have clear evidence of a material object moving faster than light?" > Regarding the continuation of the conversation, York wrote in 1984 that Fermi "followed up with a series of calculations on the probability of earthlike planets, the probability of life given an earth, the probability of humans given life, the likely rise and duration of high technology, and so on. He concluded on the basis of such calculations that we ought to have been visited long ago and many times over." The original discussion wasn't about us detecting aliens out there in the universe. It was about aliens coming here to contact us. I think they knew that the chances of detecting an electromagnetic signal from another world were next to nil. There's too much attenuation on broadcast signals over light years of distance so it would require the other civilization to directly target your planet with a high powered signal. Since, according to the quotes above, Fermi thought that eventually we might be able to find a way to travel faster than the speed of light it makes no sense for an alien civilization to even attempt such a method of communication which is necessarily bounded by the speed of light. All of the discussions of the Fermi paradox in recent history have assumed that the speed of light is inviolable and so we should only be looking for radio signals. Based on this, I choose to believe that the solution to the paradox is that FTL travel is possible and our system has already been discovered but the discoverers have simply chosen not to contact us for whatever unknowable alien reason they may have (zoo hypothesis most likely). We don't see them or evidence of any other civilization because they likely don't use radio or laser transmission because it is obsoleted by whatever technology enables faster than light travel. That simply means we have no possible way of detecting an alien craft except by visually imaging them or directly pinging them with radar. That's hard enough to do with asteroids in predictable orbits, a craft that's being intelligently controlled and which has the capability to exceed the speed of light would be next to impossible to get a bead on. If you think about it, FTL technology would remove the need for a lot of the "signatures" that we can look for. Any form of EM communication is painfully slow compared to it. Megastructures or astroengineering are pointless if you can travel anywhere in the galaxy within a reasonable time frame, you can easily bring any resource you need back home or go to any desirable location. There would be no drive plumes or giant laser pulses to detect fleets of ships travelling between stars. All this is assuming that FTL is fairly "cheap" in that it doesn't require a massive engine or the resources of an entire solar system, perhaps there is some reasonably accessible way to control gravity something that we'd be able to achieve given another hundred years. So perhaps we are unlucky enough to be within the empire of a civilization that doesn't want to talk to us. Maybe that's lucky since contact with such an advanced civilization would radically alter our society and we'd probably wind up being absorbed by their culture.