"Two possibilities exist: either we are alone in the Universe, or we are not. Both are equally terrifying." - Arthur C. Clarke
I notice a lot of people seem to be highly optimistic about finally encountering aliens, likely as a result of our pop culture which would have us believe that we would somehow ascend into an international galactic community where everyone magically gets along, everyone trades peacefully and it will all be great and utopian. Just wanted to share my two cents about what an encounter with technologically superior aliens would entail, why conflict with said aliens is inevitable and why this would mean the unavoidable extinction of either humanity, or said aliens.
Pure logic dictates that a sufficiently advanced civilization that is capable of colonizing the galaxy, would be inherently hostile to any other civilizations it encounters. And the reasons are not as immediately obvious as they seem, but it comes down to this:
  1. There is only so much stuff in the universe that is realistically accessible, even though the universe itself is infinite. The seeming impossibility of achieving FTL speeds, coupled with the distances involved and the universe's inflation (which is speeding up, according to our current understanding of science), indicate this
  2. Inevitably, the universe will decay because of entropy, meaning there is less and less stuff as time goes on. Eventually, there will be less and less stars, all matter will gradually decay to iron, the universe will keep cooling down, etc. All of our scientific understanding indicates that the universe has an "end", or at least an end to its habitable period, beyond which life will no longer be possible.
  3. While its much easier to just colonize an uninhabited planet (a civ that can go interstellar should have no issues colonizing a barren planet like, say, Mars, forgoing a costly war and environmental hazards I.E. bacteria/pathogens to claim a "habitable" world), said civilization would also be advanced enough to be aware of 1 and 2 AND to plan sufficiently ahead for both of them, likely thinking in terms of billions of years and planning for what challenges they may encounter over such periods. We've only just grasped the surface of much of this stuff and we're already starting to think like this.
  4. Therefore, said civilization would conclude that in X billion years, there will inevitably be a resource shortage due to points 1 and 2, or simply a shortage of available space to expand into.
  5. Said civilization would also conclude that any and all civilizations in the galaxy would inevitably end up fighting over said resources due to the above
  6. Said civilization would also understand that while those primitive bare-apes from Earth may not be a threat right now, their technological development would lead to them becoming a threat in X million years, pointing back to 5
  7. Therefore, it would make sense for said civilization to "nip us in the bud", killing us off before we could ever become a threat or a competitor later on, when it would be much more difficult for them to deal with us because we would have advanced and spread far more.
  8. Unlike "conquering" an inhabited planet, just wiping it clean of life would be ridiculously easy. All they have to do, when one of their ships is flying by at X% of the speed of light, or whatever is scientifically achievable, is open up their garbage chute and fling their trash at us at, say, 30% of the speed of light. There is nothing, absolutely nothing we could do to stop, deflect, or lessen the impact of such a relativistic kill vehicle to prevent our extinction and we wouldn't even detect it quickly enough to build some kind of Noah's Ark ship to escape our impending doom. We would have hours, days at most, to contemplate our inevitable extinction and that would be it, the end of all life on Earth. And that is without even considering other possible methods, such as a Nicoll-Dyson beam device (essentially, the IRL Death Star), who's "projectile", in the form of a beam consisting of the directed energy output of an entire star, would travel at the speed of light, which means we would never see it coming until it hits us.
This brings us to the Fermi paradox and one of the following possibilities:
  1. We are the first civilization in the galaxy to pass the great filter, having a head start over everyone else, hence why we're not detecting anyone and therefore WE will be the ones colonizing the galaxy and then going around playing wack-a-mole with more primitive alien civs as we discover them, sometimes in the distant future. We become the final great filter that snuffs out all other life in the galaxy.
  2. We are NOT the first civilization out there and we can't detect any others because whoever was the first, is going around doing galactic pest control and we're only still around because they haven't found us yet, or we're just far enough down the exterminatus queue that its simply not our turn yet. Someone else beat us to the punch, which means we are doomed and there is absolutely nothing we could do about it, no hope whatsoever.