Comment Re:It'll never happen (Score 2) 333
You're also assuming that such an advanced species would necessarily care about the resulting shockwave.
A massive shockwave may not be a problem for one-way trips out of the solar system to uninhabited worlds. But it presents a mighty difficulty in anyone returning home. It also precludes attempts to search for life on other worlds, as the shockwave may obliterate it. And because such a shockwave could easily destroy most life on Earth, the technology would need to be kept under tight control by trustworthy bureaucracy. Which is basically an oxymoron.
If there is no better method than an Alcubierre drive for FTL travel, that may be reason enough why we've never been visited by aliens: they didn't want to risk destroying us. After all, given even optimistic predictions of the number of habitable planets in our galaxy which are already inhabited, it doesn't really make sense to steal planets from other life forms when there may be at least dozens of uninhabited but habitable or nearly habitable planets closer than the nearest inhabited ones.