July 30, JDN 2457600

It’s not actually the top-grossing film in the US right now (that would be The Secret Life of Pets), but Independence Day: Resurgence made a quite respectable gross of $343 million worldwide, giving it an ROI of 108% over its budget of $165 million. It speaks to something deep in our minds—and since most of the money came from outside the US, apparently not just Americans, though it is a deeply American film—about the fear, but perhaps also the excitement, of a possible alien invasion.

So, how likely are alien invasions anyway?

Well, first of all, how likely are aliens?

One of the great mysteries of astronomy is the Fermi Paradox: Everything we know about astronomy, biology, and probability tells us that there should be, somewhere out in the cosmos, a multitude of extraterrestrial species, and some of them should even be intelligent enough to form civilizations and invent technology. So why haven’t we found any clear evidence of any of them?

Indeed, the Fermi Paradox became even more baffling in just the last two years, as we found literally thousands of new extrasolar planets, many of them quite likely to be habitable. More extrasolar planets have been found since 2014 than in all previous years of human civilization. Perhaps this is less surprising when we remember that no extrasolar planets had ever been confirmed before 1992—but personally I think that just makes it this much more amazing that we are lucky enough to live in such a golden age of astronomy.

The Drake equation was supposed to tell us how probable it is that we should encounter an alien civilization, but the equation isn’t much use to us because so many of its terms are so wildly uncertain. Maybe we can pin down how many planets there are soon, but we still don’t know what proportion of planets can support life, what proportion of those actually have life, or above all what proportion of ecosystems ever manage to evolve a technological civilization or how long such a civilization is likely to last. All possibilities from “they’re everywhere but we just don’t notice or they actively hide from us” to “we are actually the only ones in the last million years” remain on the table.

But let’s suppose that aliens do exist, and indeed have technology sufficient to reach our solar system. Faster-than-light capability would certainly do it, but it isn’t strictly necessary; with long lifespans, cryonic hibernation, or relativistic propulsion aliens could reasonably expect to travel at least between nearby stars within their lifetimes. The Independence Day aliens appear to have FTL travel, but interestingly it makes the most sense if they do not have FTL communication—it took them 20 years to get the distress call because it was sent at lightspeed. (Or perhaps the ansible was damaged in the war, and they fell back to a lightspeed emergency system?) Otherwise I don’t quite get why it would take the Queen 20 years to deploy her personal battlecruiser after the expeditionary force she sent was destroyed—maybe she was just too busy elsewhere to bother with our backwater planet? What did she want from our planet again?

That brings me to my next point: Just what motivation would aliens have for attacking us? We often take it for granted that if aliens exist, and have the capability to attack us, they would do so. But that really doesn’t make much sense. Do they just enjoy bombarding primitive planets? I guess it’s possible they’re all sadistic psychopaths, but it seems like any civilization stable enough to invent interstellar travel has got to have some kind of ethical norms. Maybe they see us as savages or even animals, and are therefore willing to kill us—but that still means they need a reason.

Another idea, taken seriously in V and less so in Cowboys & Aliens, is that there is some sort of resource we have that they want, and they’re willing to kill us to get it. This is probably such a common trope because it has been a common part of human existence; we are very familiar with people killing other people in order to secure natural resources such as gold, spices, or oil. (Indeed, to some extent it continues to this day.)

But this actually doesn’t make a lot of sense on an interstellar scale. Certainly water (V) and gold (Cowboys & Aliens) are not things they would have even the slightest reason to try to claim from an inhabited planet, as comets are a better source of water and asteroids are a better source of gold. Indeed, almost nothing inorganic could really be cost-effective to obtain from an inhabited planet; far easier to just grab it from somewhere that won’t fight back, and may even have richer veins and lower gravity.

It’s possible they would want something organic—lumber or spices, I guess. But I’m not sure why they’d want those things, and it seems kind of baffling that they wouldn’t just trade if they really want them. I’m sure we’d gladly give up a great deal of oregano and white pine in exchange for nanotechnology and FTL. I guess I could see this happening because they assume we’re too stupid to be worth trading with, or they can’t establish reliable means of communication. But one of the reasons why globalization has succeeded where colonialism failed is that trade is a lot more efficient than theft, and I find it unlikely that aliens this advanced would have failed to learn that lesson.

Media that imagines they’d enslave us makes even less sense; slavery is wildly inefficient, and they probably have such ludicrously high productivity that they are already coping with a massive labor glut. (I suppose maybe they send off unemployed youths to go conquer random planets just to give them something to do with their time? Helps with overpopulation too.)

I actually thought Independence Day: Resurgence did a fairlygood job of finding a resource that is scarce enough to be worth fighting over while also not being something we would willingly trade. Spoiler alert, I suppose:

Molten cores. Now, I haven’t the foggiest what one does with molten planet cores that somehow justifies the expenditure of all that energy flying between solar systems and digging halfway through planets with gigantic plasma drills, but hey, maybe they are actually tremendously useful somehow. They certainly do contain huge amounts of energy, provided you can extract it efficiently. Moreover, they are scarce; of planets we know about, most of them do not have molten cores. Earth, Venus, and Mercury do, and we think Mars once did; but none of the gas giants do, and even if they did, it’s quite plausible that the Queen’s planet-cracker drill just can’t drill that far down. Venus sounds like a nightmare to drill, so really the only planet I’d expect them to extract before Earth would be Mercury. And maybe they figured they needed both cores to justify the trip, in which case it would make sense to hit the inhabited planet first so we don’t have time to react and prepare our defenses. (I can’t imagine we’d take giant alien ships showing up and draining Mercury’s core lying down.) I’m imagining the alien economist right now, working out the cost-benefit analysis of dealing with Venus’s superheated atmosphere and sulfuric acid clouds compared to the cost of winning a war against primitive indigenous apes with nuclear missiles: Well, doubling our shield capacity is cheaper than covering the whole ship in sufficient anticorrosive, so I guess we’ll go hit the ape planet. (They established in the first film that their shields can withstand direct hits from nukes—the aliens came prepared.)

So, maybe killing us for our resources isn’t completely out of the question, but it seems unlikely.

Another possibility is religious fanaticism: Every human culture has religion in some form, so why shouldn’t the aliens? And if they do, it’s likely radically different from anything we believe. If they become convinced that our beliefs are not simply a minor nuisance but an active threat to the holy purity of the galaxy, they could come to our system on a mission to convert or destroy at any cost; and since “convert” seems very unlikely, “destroy” would probably become their objective pretty quickly. It wouldn’t have to make sense in terms of a cost-benefit analysis—fanaticism doesn’t have to make sense at all. The good news here is that any culture fanatical enough to randomly attack other planets simply for believing differently from them probably won’t be cohesive enough to reach that level of technology. (Then again, we somehow managed a world with both ISIS and ICBMs.)

Personally I think there is a far more likely scenario for alien invasions, and that is benevolent imperialism.

Why do I specify “benevolent”? Because if they aren’t interested in helping us, there’s really no reason for them to bother with us in the first place. But if their goal is to uplift our civilization, the only way they can do that is by interacting with us.

Now, note that I use the word “benevolent”, not the word “beneficent”. I think they would have to desire to make our lives better—but I’m not so convinced they actually would make our lives better. In our own history, human imperialism was rarely benevolent in the first place, but even where it was, it was even more rarely actually beneficent. Their culture would most likely be radically different from our own, and what they think of as improvements might seem to us strange, pointless, or even actively detrimental. But don’t you see that the QLX coefficient is maximized if you convert all your mountains into selenium extractors? (This is probably more or less how Native Americans felt when Europeans started despoiling their land for things called “coal” and “money”.) They might even try to alter us biologically to be more similar to them: But haven’t you always wanted tentacles? Hands are so inefficient!

Moreover, even if their intentions were good and their methods of achieving them were sound, it’s still quite likely that we would violently resist. I don’t know if humans are a uniquely rebellious species—let’s hope not, lest the aliens be shocked into overreacting when we rebel—but in general humans do not like being ruled over and forced to do things, even when those rulers are benevolent and the things they are forced to do are worth doing.

So, I think the most likely scenario for a war between humans and aliens is that they come in and start trying to radically reorganize our society, and either because their demands actually are unreasonable, or at least because we think they are, we rebel against their control.

Then what? Could we actually survive?

The good news is: Yes, we probably could.

If aliens really did come down trying to extract our molten core or something, the movies are all wrong: We’d have basically no hope. It really makes no sense at all that we could win a full-scale conflict with a technologically superior species if they were willing to exterminate us. Indeed, if what they were after didn’t depend upon preserving local ecology, their most likely mode of attack is to arrive in the system and immediately glass the planet. Nuclear weapons are already available to us for that task; if they’re more advanced they might have antimatter bombs, relativistic kinetic warheads, or even something more powerful still. We might be all dead before we even realized what was happening, or they might destroy 90% of us right away and mop up the survivors later with little difficulty.

If they wanted something that required ecological stability (I shall henceforth dub this the “oregano scenario”), yet weren’t willing to trade for some reason, then they wouldn’t unleash full devastation, and we’d have the life-dinner principle on our side: The hare runs for his life, but the fox only runs for her dinner. So if the aliens are trying to destroy us to get our delicious spices, we have a certain advantage from the fact that we are willing to win at essentially any cost, while at some point that alien economist is going to run the numbers and say, “This isn’t cost-effective. Let’s cut our losses and hit another system instead.”

If they wanted to convert us to their religion, well, we’d better hope enough people convert, because otherwise they’re going to revert to, you guessed it, glass the planet. At least this means they would probably at least try to communicate first, so we’d have some time to prepare; but it’s unlikely that even if their missionaries spent decades trying to convert us we could seriously reduce our disadvantage in military technology during that time. So really, our best bet is to adopt the alien religion. I guess what I’m really trying to say here is “All Hail Xemu.”

But in the most likely scenario that their goal is actually to make our lives better, or at least better as they see it, they will not be willing to utilize their full military capability against us. They might use some lethal force, especially if they haven’t found reliable means of nonlethal force on sufficient scale; but they aren’t going to try to slaughter us outright. Maybe they kill a few dissenters to set an example, or fire into a crowd to disperse a riot. But they are unlikely to level a city, and they certainly wouldn’t glass the entire planet.

Our best bet would probably actually be nonviolent resistance, as this has a much better track record against benevolent imperialism. Gandhi probably couldn’t have won a war against Britain, but he achieved India’s independence because he was smart enough to fight on the front of public opinion. Likewise, even with one tentacle tied behind their backs by their benevolence, the aliens would still probably be able to win any full-scale direct conflict; but if our nonviolent resistance grew strong enough, they might finally take the hint and realize we don’t want their so-called “help”.

So, how about someone makes that movie? Aliens come to our planet, not to kill us, but to change us, make us “better” according to their standards. QLX coefficients are maximized, and an intrepid few even get their tentacles installed. But the Resistance arises, and splits into two factions: One tries to use violence, and is rapidly crushed by overwhelming firepower, while the other uses nonviolent resistance. Ultimately the Resistance grows strong enough to overthrow the alien provisional government, and they decide to cut their losses and leave our planet. Then, decades later, we go back to normal, and wonder if we made the right decision, or if maybe QLX coefficients really were the most important thing after all.

[The image is released under a CC0 copyleft from Pixabay.]