Thanks by the way Tora for the supportive post you made earlier. Much appreciated.
"Therefore I rule it out because we'd need to make discoveries that would rewrite physics. I just don't buy it."
Indeed, there's the rub. Modern physics might well have to be spectacularly -- entirely -- wrong, in order for at least some of the ideas proposed to be anything other than theoretical curiosities. The idea exists, for example, of wormholes that would allow a relatively speedy transport from one point to another without breaking any form of limit. Unfortunately, the energy involved in what is essentially tearing a hole in the Universe is rather a lot more than that I suggested we needed for a more direct approach, so that's probably not going to lead very far either!
One of the as-yet unsung consequences of the paper that I cited in another thread, that would appear to confirm Inflation Theory, is that it essentially establishes that our understanding of Physics is right, not just here and now, but everywhere in the Universe and for almost its entire history, except maybe the first fraction of a second when something's certainly missing. In that context it would be surprising, to say the least, if we were utterly wrong about how Relativity works after all, or perhaps if the Laws of Physics suddenly change in the near future in a way that would make my calculations wildly pessimistic. As it is I'm fairly sure it's wildly optimistic to assume that you would need "only" 1000 times as much energy as the entire World consumed in 2010, focused into a single burst of maybe a few seconds and utilised with about 100% efficiency.
Still, just because I don't think we'll be able to succeed doesn't mean I don't think we should try. And given how incredibly exciting it would be to be able to interact with another species from an entirely different planet, I'd love to be wrong.