This is just a short, easy-to-read paper I keep in my bookmarks and go back to occasionally. It explores, qualitatively, the various outcomes that contact with alien intelligence might have. I think it's a really cool 25-page exploration of possibilities that are fun to think about. Some choice quotes:
ETI (extraterrestrial intelligence) might attack us not out of selfishness but instead out of a universalist desire to make the galaxy a better place.
perhaps ETI make contact with Earth to welcome us into the Galactic Club but only after we complete a set of required bureaucratic tasks
They may be interested in incorporating us into their civilization so they can sell us their products, keep us as pets, or have us mine raw materials for them.
if ETI place intrinsic value on lives, then perhaps they could bring about more lives by destroying us and using our resources more efficiently for other lives
My favourite section is the "unintentional harm" outcomes, which suggests the possibility that they just might squish us by accident.
One non-biological physical hazard that we could face from direct contact with ETI is unintentional mechanical harm. For example, ETI might accidentally crush us while attempting an unrelated maneuver.
Can't for the life of me find where I first heard of this, but I just wanted to share it for being fun and fairly silly yet still officially worked on by NASA.
Ultimately, I think leftist thought might be the most immune to the culture thought of aliens deciding to show themselves (or us finding them). Liberals would crash the market instantly and turn on each other on an international level (Every one of them would want THEIR nation to be first contact) and fascists would use it to justify a one world fascist government. Religious but philosophically dead freaks would break down mentally (IE most american christians simply are not ready for the idea of intelligent life off world).
Aliens don't inherently mean anything to leftist ideas. Sure a overall "good" future leftist government(s) could botch contact real bad. But if Lenin knew there were little green men 10 million light years away that couldn't even talk to us, would it have changed anything?
Ultimately, aliens existing doesn't mean anything to the material conditions on earth, unless they can directly effect us (IE, give us tech, destroy us, etc etc). Hell even if we learned that the aliens were Space Hitler, it still wouldn't mean much. It'd be concerning, and liberals and fash would use it to say we should follow their lead, but it'd be pretty irrelevant to humans by itself (unless they're in orbit but that'd be another concern).