More research for scifi stories: What the "theoretical" limits on the size of a radio telescope (assuming great advances in manufacturing techniques and unlimited resources). I know the resolution is dependent on how far apart you place the individual components, so could you in theory have one that spanned the entire solar system? Even larger? I know relativity at some point would make synchronizing the signals difficult, but assuming you could compensate for this? What becomes the limiting factor? In a related question, is it even withint the realm of possible theory (assuming amazing advances in technology and again unlimited resources but no fundamental changes to the laws of physics as we know them) to build some sort of telescope that would have enough resolution to make out small structures on the surface of a planet 5 light years distant? Would a series of fortunately place black holes contributing some gravitational lensing change the answer at all? Is there some specific resolution that reaches some theortical limit based on the laws of physics (as opposed to the quality of raw materials and production techniques within our reach)? If so, what causes it, and can it be accurately determined? Thanks!