Avoiding Aliens

I think just a few things can be said on any potential contact with intelligent alien life:1) They're not likely to be able to get here easily. So far as we know, you can;t go faster than light, meaning even relatively "close" civilizations will take thousands of years or more to travel interstellar distances.2) The reason to come here will never be "resources." It's easier to acquire resources by far in an asteroid belt or on low-gravity or even by mining uninhabited worlds than by wasting resources in a war.Now, none of this precludes aliens that, while intelligent enough to travel interstellar distances, are also stupid enough to waste resources by attacking another intelligent civilization with the capability to fight back when easier choices are innumerably common. This would include aliens on some religious crusade to wipe out all other life, aliens that just "don't like us," or any other ridiculous reason to expend massive amounts of resources in travel followed by still more resources and manpower executing military action despite the fact that they'd get easier returns by mining an asteroid belt and harvesting water from comets and such.The only intelligent reason to come here would be for scientific research. This could take the form of non-interventionist observation, or it could take the form of capture and dissection. Even though this could potentially justify an interstellar trip, it seems to me that it would be far easier to simply establish an open line of communication and ask us what they want to know about life on our world rather than (again) committing to an unnecessary expenditure of resources.Comparisons to the discovery of the Americas are simply invalid. Columbus and those who followed sought resources, and on Earth that meant trading with or conquering whoever already claimed those resources. In this case, the technological level of those who claimed the new resources was low enough to make conquest an easier and arguably more profitable response (in addition to religious motivations to convert the heathens).In space, the vast majority of resources aren't claimed by anyone, and no conquest is necessary. You don't have to fight anyone off to strip-mine some asteroids or tap Europa for water. In a simple quest for resources for a nomadic space faring society, why bother with the mess of interstellar war when there's no need to do so?I'd fear contact with religious extremist aliens, myself, because I think that sort of irrational drive would "justify" ridiculous expenditures of resources with no additional good reason, but short of that, color me unconcerned.

That assumes an alien biochemistry compatible with our own biosphere.Further, for a nomadic race, it's significantly easier to build orbital habitats in resource-rich solar systems than to seek out pre-existing biospheres that may be compatible with your species' biology. Bringing resources in and out of a gravity well is extremely energy-intensive, while bringing them to and from orbital facilities is relatively trivial.In the case of our own solar system, it would be far easier to set up orbital habitats around Mars, and mine the nearby asteroid belt (and even Phobos and Deimos) for mineral resources than it would be to establish a permanent settlement on Earth. Less travel time, no gravity well, no atmospheric concerns for transportation, and easy to pack up and move when the time comes.Conquest for the use of a pre-existing biosphere also makes the actual warfare far more costly in lives and resources than other "kill all humans" scenarios. If you just want to kill us all, tow some asteroids into an unstable Earth orbit and watch a mass extinction. Fire off some nuclear warheads, whatever. But you wouldn't want to do those things if your goal was to live here after the conquest was complete - you'd be destroying the very biosphere you want to steal. You'd have to resort to landing troops and more conventionally-scaled bombings, and we'd have far more of an opportunity to fight back than in a "drop some asteroids" scenario.But again, all this assumes that alien life would find our own biosphere to be compatible with their own biology. That's a rather large assumption. This isn't Star Trek, where everyone is basically humanoid, breathes oxygen in the same basic concentration that humans do at the same atmospheric pressures humans do with the same gas mix found on Earth, and speaks English. We evolved to be compatible with our environment. An alien species will have evolved to be compatible with their own world, which would almost certainly be significantly different from our own.

Remember, we're talking about a nomadic space-faring race that already possesses sufficient technology to transport their civilization across interstellar distances.This means they are, in effect, already existing in spaceborne habitats, simply with engines attached. We can safely assume that they have solved such problems as long-term living space, population growth, radiation, and internal food production simply because they would need to have solved such problems simply to get here in the first place.The exception would potentially be some sort of cryogenic colony ship that stores the biological population in suspended animation for the journey, and wakes them up on arrival. They would still, however, need to have sufficient living space for their entire military (since a frozen army doesn't conquer anyone) at a minimum. Issues of radiation shielding and food production are still prerequisites in this scenario - you still can't get here or stage an invasion without having solved them. I think you're starting to enter the realm of magic-tech. I don't for a moment suggest that we could actually repel a sufficiently advanced race, but at some point they're still going to face issues of logistics, where we have a well-established chain of logistics for food, ammunition, replacement parts, weapons, and manpower, while the invaders exist in orbiting spacecraft with essentially no logistical support (that being the reason they want Earth in the first place). If we assume that they first establish a logistical chain by taking advantage of our solar system's other resources like comets and asteroids, what are they invading for again?The fact is, even if we're analogous to the Native Americans with the invasion of the Europeans, they need to establish a foothold on our territory fast or they soon lose their ability to sustain an offense because their logistical support is limited by what they brought with them in their ships. And while we may be at a technological disadvantage, I thin kit's reasonable that, faced with extermination by an invading alien force, we would immediately nuke the living fuck out of any such beach head - and I don't think it's reasonable to say "maybe their technology is sufficiently advanced that they are impervious to nuclear weapons," because that would mean we're being invaded by fucking Kryptonians, and inevitably a similarly physics-breaking superhero will rise to our rescue. Honestly, they're no more likely to be somehow impervious to our own weapons through sufficiently advanced technology than you or I are immune to an arrow from a 15th-century Native American.Similarly, I think it's reasonable to assume that we'd attempt nuclear strikes (and kinetic-kill weapons) on their spacecraft in-system.The best way to take us out is a massive kinetic-kill attack using towed asteroids and dropping them on us. We'd have very little real defense against big fucking rocks from the sky. The problem is that such attacks would also destroy the biosphere - the only reason in this scenario they'd be attacking in the first place, which again begs the question, "what are they doing here, again?"

Well, the conversation was essentially one regarding the attempt by SETI to detect alien life, and the logical next step of beginning a dialogue.The scenario itself requires a society capable of emitting electromagnetic signals like radio, since that's what we're listening for. I think the entire conversation disregarded non-intelligent life not because of which is more likely to exist, but because which was more relevant to SETI.I think the more unreasonable assumptions are ones that assume an intelligent species will:1) have the technology and resources to build interstellar spacecraft
2) have sufficient motivation to expend those resources and the time required to get here
3) will bother with Earth as a source of resources when we are looking at space for the future of industry in the form of asteroid mining, because it's just that much easier and you don't have to worry about ruining a biosphereAnd honestly, the entire question is moot - whether we seek contact or not is irrelevant, because we're already bleeding all over the radio bands for anyone to see if they're in range. If there's a scary "exterminate the humans" evil alien overlord out there, the damage in terms of letting them know we exist has already been done.

Well, we do know a few things. We know how we, for example, would fare on worlds where the conditions were even slightly different from our own. I'm not even talking about something as basic as a lack of oxygen; I mean things like atmospheric pressure and specific gas mixes. We know that we would need specialized equipment to survive in an environment with significant differences from those found on Earth, and that at a certain point we'd no longer be looking at a compatible biosphere, and we would be just as "comfortable" on Mars.It's perfectly reasonable to hypothesize that alien life, having developed on a world other than Earth, would have evolved to tolerances based on the conditions of their world, which would almost certainly be different from those on Earth.We also know the relative energy requirements to deal with a gravity well, and we know that if you've already solved the basic issues of space flight (as any interstellar civilization must have by definition), it's far less resource-intensive to mine asteroids than to haul minerals out of a deep gravity well. We know that, in order to travel interstellar distances, you must have already developed a habitat capable of supporting life for long periods of time for your entire population in space, making orbital habitats possible (since a ship is just a habitat with engines).One of the most reasonable suggestions I've read surrounding space-faring civilizations involves mining asteroids by hollowing them out, and using the interior as habitation space. The asteroid shell serves to effectively block out radiation and protect from normal impacts, while being already in space so you don't have to do much in the way of hauling. You can mine nearby asteroids for additional resources, and eventually attach a form of propulsion. Sufficiently large asteroids can be used to house entire functioning biospheres, while you use fission or fusion for power generation that can last a long, long time. You can use your asteroid habitat as an interstellar generation ship if necessary. Such a civilization would never have any need to enter a planetary atmosphere and subject themselves to the many disadvantages to productivity carried by a gravity well.Given that we're already acting like a giant "HI, WE'RE HERE, HOW ARE YOU!" beacon by broadcasting radio signals even without any SETI beacon, and given that the chances of an alien race both having teh capability and the desire to snuff us out seem rather slim, I'm not exactly going to lose sleep.

1) "Nanobots" don't work in reality like they do in movies. They can still be pretty cool, but you're not going to see the "gray goo" nano-disassembler stuff you see in fiction. On the nanoscale, things work slowly. You can't make a few million nanobots disassemble a human-sized organism quickly - molecule-by-molecule action is not fast. You also need to be able to somehow provide the bots with energy, while still keeping them small enough to do their jobs. If you want to be able to inhabit the area after they're done, you need to make them intelligent enough ti distinguish you from their targets - all at the nanoscale. This approaches what is commonly referred to as "wank," taking a technology and exaggerating its capabilities while ignoring its drawbacks until you completely depart from reality. You can kill things much quicker and easier.2) Biological warfare doesn't work as well as you might like. We have some pretty nasty stuff already (smallpox, anthrax, etc), but the fact is, even airborne pathogens are unlikely to be of significant use in a war of extinction. It should be relatively simple for an alien species to "design" a virus or other pathogen that works on us but not on them (they could probably just use something from Earth in weaponized form assuming their biology is significantly different from ours), but once again you run into the fact that you can get better results quicker and easier elsewhere. Biological weapons don;t spread efficiently. The few times they've been used, we've observed that they disperse very quickly and don't have nearly the impact hoped for. They make excellent terror weapons and can easily sneak by security, but they don;t work well for killing off large populations.If you want to assault a planetary population like ours (one with at least a token capacity to fight back), there are much easier ways, even if you want to preserve the biosphere.The best solution? Targeted, not widespread, use of kinetic kill impacts followed by fortification of cleared ground. We wouldn't even see it coming. As the attacker, you'll know the mass and speed of your kinetic kill projectiles (likely just asteroids), and can target them at population centers for a simultaneous impact while leaving the less developed areas (ie, the ones with the least capacity to fight back and the most functional parts of the ecosystem) relatively unscathed. Ecological impact will primarily be in the form of dust clouds, but effectively limiting the size of the impact projectiles will reduce the recovery time. Destroy any and all artificial satellites immediately after the initial attack. Use space-based mining to create a logistics train. Wait for the ecological damage from the asteroids to clear while keeping a token military presence in orbit to use tactical-level kinetic-kill objects to eliminate any sort of recovery effort from the survivors (small ones shouldn't cause long-term ecological damage) with the goal of preventing the retention or recovery of meaningful resistance against a space-borne enemy (ballistic missiles, airplanes, power generation, significant groups of survivors). After all of the dust has settled and life is beginning to recover, land beginning with your military to fortify and set up infrastructure. Don;t worry about the remaining humans, so long as you continue to quickly respond to any attempt to gather in significant numbers. Begin to send out military units to scout out and destroy remaining stockpiles of human weapons. Once the potential for resistance is effectively destroyed and necessary planet-side infrastructure has been established, begin landing the civilian population.That would be my suggestion. And, of course, there's not really any way for us to defend against it at the moment. The best chance would be to detect the thermal signature of the invasion fleet when they approach the solar system. At that point we may have up to a few years before the asteroids are ready to be redirected to their targets with which to re-tool existing weapons like ballistic missiles to be used against enemies beyond low-Earth-orbit. But if they are able to launch several dozen asteroids targeted at different population centers simultaneously, I don't see a way for us to survive.

The analogy doesn't follow, Taz. We (and I, specifically) have imagined, in this cery thread, that alien civilizations could exist, and that they could have the capacity to reach us. Since when was the last war fought because "Hey, there are some guys on the other side of the world who don't even know we exist and who aren;t sitting on any resources we can't find elsewhere and who are not affecting our lives in any way whatsoever, let's go smash em!"Wars are usually fought for reasons, Taz, even when the reasons are bad. Most of our wars are over resources (most of our involvement in the middle East is done to retain some semblance of stability for the oil market) or ideological nonsense (the remainder of the reason we concern ourselves with the Middle East, of course, being Israel). The Cold War was "fought" over different ideologies that posed an assumed threat towards each other (that one side would attempt to forcibly take over the territory and thus resources of their competitor, or would attack to preempt such a strike).Resources on Earth are concentrated in specific areas and are already controlled by existing nations, and it's been this way since we discovered we could use the resources in question. Neighbors have been close enough to pose a tangible threat to each other and to directly compete for resources.Space is different. It's huge. Resources are not concentrated in controlled areas. If the Vulkans need more radioisotopes, they can simply get some from the nearest asteroid, with absolutely no reason to come and take ours. If the Trandoshans have completely exhausted their solar system's resources, they can still get more from the nearest asteroid in a neighboring star system far easier than they could by coming all the way over here to take ours by force. If Emperor Xenu holds a vastly different political ideology from ours, we still don't pose any sort of threat to his rule on the other side of the galaxy. Slave labor is easier to accomplish through cloning or (far better) robotics.The only reason I can think of for an alien race to come and try to kick our collective ass is some sort of religious crusade. Certainly a possibility and the subject of many stories in fiction, but as we can't really defend against a war of extermination executed from space, I don't see any reason to worry about it. Since when was the last time a big war was fought strictly over resources? Again, this is narrow-minded thinking, the same kind that brought the native americans to their doom. The Spaniards under Columbus were traveling to India, a place they knew had resources that were unattainable elsewhere.Our solar system doesn't have any resource that wouldn;t be present in any other solar system in abundance, except for an intelligent species that might be able to fight back.The Spaniards arrived in the Americas by accident, and still did not set out immediately to conquer and exterminate.The destruction of native culture was a long process, and was mostly the result of small colonies that later decided to either a) get rid of the natives so they could have more resources, or b) convert the natives for Jeebus.a) is not an issue in space. There is no reason to colonize Earth. Their biologies are almost certainly to be completely incompatible with the conditions on Earth. They don't need to steal our gold or spices or land or water or radioisotopes or metals because it's easier to get all of those things elsewhere.b) is a potential issue. Religious crusades override any bounds og logic or reasonable expenditures of resources. Religious zealots from spaaaaace are the only threat I would consider truly plausible.Edited by Rahvin, : No reason given.

We know the limits of these technologies to a reasonable degree, Taz. Biological warfare that attacks only a specific species while leaving the rest of the ecosystem and the invaders untouched is a pipe dream. Nanotech disassembler robots that magically kill off a population are magic-tech wank.I already described very easy methods to take over a planet. It's not like I'm ignoring the possibility and dismissing everything - I'm just dismissing the "lol, I saw this once in a movie" nonsense, because get this - fiction writers don't know jack about what they write about 9/10 of the time, and that's where most of these ideas are coming from.Dropping asteroids on a planet targeted at population centers is an incredibly resource-lite and technologically simple first-strike attack that also happens to be wildly effective and doesn't require breaking our understanding of the laws of physics (like, say, nano-dissasemblers that turn people into goo in a reasonable timeframe).I'd also be dismissive if someone said I should start worrying bout the fucking Death Star showing up and blowing up the planet. Lasers can't make planets go boom, regardless of power output, full stop. Lasers don;t behave the way the Death Star superlaser did on film (being visible, joining multiple smaller beams into one large beam going a different direction...). I'm dismissive of "lol virus attack!" and "Nanotech, LIKE TEH BORG!" for similar reasons.I'm also dismissive for the most part of the motivation an alien species would have to come here. So far as we understand, FTL is not possible. That means that there is no reasonable threat posed by cheap, easy, FTL travel like what we see in movies. The reasonable methods by which an alien race would come here involve extremely long travel times with a significant investment in resources, and an STL approach that we very well may see years in advance because of the thermal (and possibly other) emissions of the ship(s). That means a machine race, or cryonic storage, or massive generation ships. Like I;ve suggested previously.The extreme cost of traveling such distances precludes rational beings from making the trip just to kill us; we are no threat to them, and we aren't in competition for resources.That leaves, as I said, the crazies on a crusade. Religious mandates to exterminate life, or just a pathological need to kill "them," either way the only plausible motivation to come kill us involves the aliens being nuts that are willing to make unreasonable expenditures of resources and take enormous risks with their personnel to pick a fight with somebody on the other side of the galaxy in a conflict that will take eons of set up because it will take multiple lifetimes lust for the combatants to reach the fucking battlefield.Do you have anything substantial to say, or are you simply going to continue with your wonderfully vague "lol, expect the unexpected" platitudes? Outside-context problems are certainly a threat, and I don;t pretend for a moment that we know all there is to know about the Unvierse and ways to kill, but a) by definition I won;t be able to consider the possibility of a true outside-context threat until after I see it (only Batman can lay down contingency plans like that, and last I looked I wasn;t a fictional character) so there's no practical reason to concern myself, and b) you're essentially telling me I should throw out what we do know, because "they'll be smarter than us lol." That's retarded.It's perfectly rational to consider the fact that resources cannot be the driving motivation being an invasion of Earth, and that Earth's biosphere will almost certainly be at least somewhat hostile to a species that evolved on a different world which crosses "habitable planet" off of the resources list as well. It's perfectly rational to point out that technology has limitations - suggesting "maybe they just know more about nanotech and viruses than we do" is just like George Lucas using a really big laser to blow up a planet: it just doesn't work that way, and pretending it might is still just wank.