.. for while it is true that they would need to know cooperation on a massive scale--it's also probably true that this cooperation was probably massively employed to dominate their own planet and all other species on it to a level that we've not achieved.

So.. are we going to be pets or pests?

Personally--if they show up--and they don't like us.. we're boned. They will just drop rocks on us from space and wait for us to die off.. then colonize and mop up any remaining pesky hairless apes.

I gotta say, Empire Ship isn't exactly a ringing endorsement for the Benevolent Space Traveler theory.

Space Jehovah's Witnesses. Just as obnoxious but MUCH harder tog et off your doorstep.

You know I just have no idea.

I can see his point about being cautious. I'd rather veer on the side of caution than tell everyone where the homeland is and they end up being something nasty. I wouldn't presume to describe what exactly an alien species would be like, however.

The only true first-contact model we have is ourselves--and look how things turned out for the Native Americans. Sure, aliens will show up pretending to be our buds, and then they'll exile us all to...New Jersey. Calcutta. Siberia. Someplace like that. It's not looking good, is all I can say.

I kinda hate to think of it that way, especially given my hopes for peaceful and mutually beneficial contact, but skepticism is probably more called for on this matter. ::sad::

You forgot the other options:

They are already here and living among us.

They stopped by eons ago and found us uninteresting and our planet of no use. They might come back once we've finished off all this pesky carbon-based life form garbage and each other.

They made us, and this is just one big lab experiment.

I'd guess that given the range of environments in which creatures can survive on this planet, it's entirely possible that creatures from other solar systems wouldn't be able to survive on Earth, even with massive life support--too hot or cold or windy or wrong atmosphere or gravity or whatever. I rather like John Christopher's Tripod trilogy, but I always wondered why the Masters wanted to go to all that trouble of "terra"forming Earth to their specifications, as the planet was otherwise completely unsuitable.

Ticky boxes: Good.

Complaint box: good.

Lack of cats: very bad, as they will be our salvation from the alien menace. Or they are the aliens.

Let us assume that there is an alien intelligence that doesn't choke on its own pollution, nuke itself out of existance, or get bogged down in a war of all against all even before reaching nuke stage of technology because it has no self-control. Or maybe just didn't spend so much money on their military that their major industrial powers went broke.

Let us then assume that these aliens don't go the other extreme and become a bunch of peaceful Bhuddists and Taoists sitting around meditating or fishing.

Let us then assume that they aren't hit by an asteroid or wiped out by some other natural disaster because they were too short-sighted to take precautions.

And that they have found ways to bridge interstellar space in a scientifically and economically viable fashion and yet lack the technology to make their own world sustainable.

Thus, while I find the idea of any alien species fitting this description highly unlikely, if they make it here, they are probably smarter and more peaceful than we are, and they probably came out of curiousty rather than need, there is one more thing to consider.

Most of the resources they might need from Earth, such as water, fuel, atmospheres, can be found or processed from raw materials found on Saturn, Titan, Jupiter, the Jovian moons... they wouldn't have to bother fighting or even bargaining with us at all.