This addresses one of the problems I've had with the Fermi Paradox, maybe the best we'll be able to do is a fairly clunky fusion plant that requires tritium (and therefore lithium), I've thought we're closer to the limits of engineering than speculative interstellar pundits assume. Carbon nanotubes or filaments are probably close to the strongest material possible and superconducting magnets are probably close to generating the strongest confinement too. Even 1 or 2% of the speed of light may be the practical limit. My second issue is that endless growth is desirable, hopefully any species technologically that advanced will also see the futility of filling the universe with potentially self destructive experiments.[theness.com]