It seems to me, the rate at which extrasolar planets (or exoplanets, but not exosolar planets, sorry Jenny Randles
) are being detected and analysed has rendered the SETI approach useless for now. We will soon have targets that offer far more promising possibilities than can be offered by the relatively random approach previously taken by SETI. A developed planet may already have been detected, the data waiting to be analysed. Once that discovery is made, then we can direct a signal to that location if we feel it's the correct thing to do.
As for this interminably raised question of whether we
should contact life elsewhere, I think the answer is we may just as well. The idea that we can look at examples from human history to judge what might happen when two planetary civilisations collide seems flawed to me.
Firstly, Europeans didn't destroy native populations on distant continents because those natives sent Europe a message in a bottle. Europeans where ready to explore further, and discovered those lands. If an alien civilisation is ready to spread its influence throughout the galaxy, we will be found, and we will have to deal with that one way or another. If we discover there is a civilisation a hundred and fifty light years away that has a heavily industrialised economy, detectable through its atmosphere, its now a hundred and fifty years further on. We can be fairly sure it has either decimated itself through carelessness by now, or in the intervening hundred and fifty years has become more advanced than us, and long since detected our presence.
Secondly, the idea that such a civilisation would want anything more than casual conversation and information exchange seems based on a
Star Trek idea of the Galaxy, where humans with prosthetic make-up on swan about chatting in English, swapping minerals and food and artefacts between each other. As far as we know, superluminal travel is impossible, or in practice uneconomical, so alien beings would need a good reason to want to come here. Contrary to
Independence Day, I don't see that we have resources on this planet that compare remotely with those obtainable in space by space-faring beings. Energy is abundant in the universe, as is water and mineral wealth, and given our own progress, any such civilisation would long since have begun constituting their own purpose made metamaterials. Our food, and even our air, would be poisonous or at the very least unpleasant to them, in all likelihood, and any attempt to change those things would upset the planet so much as to render its study pointless. We had good economical reasons for exploring the frontiers of our world. We have few good reasons for travelling to the frontiers of the Milky Way, besides curiosity.
Of course, it's possible that superluminal travel is both possible and easy once you know how, and a galactic civilisation exists, technologically thousands of years ahead of us, and it's only a matter of time before they find us. If that's the case, we can't do a darn thing to stop such godlike beings doing as they will with us. But if such a network of beings exist throughout the Galaxy, I think we would have detected them by now.
