In my setting we have two Kardashev type III civilizations who have been at war a long time and their war has now shifted into our neighborhood. These civilizations are until now unaware of human existence (Humans are type II by now). Humans, however, are by lucky chance aware of the war.

In these circumstances what would be the steps taken by humans to safeguard themselves from the ill effects the war may have on them?

I have read this question but the answers don't really cover it. I would like a diplomatic and political approach which safeguards humans from the possible ill effects of the war

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    $\begingroup$ Realistically, there's nothing we can do. They would be so much more advanced than us that we would stand no chance to defend ourselves if things went sideways. At the same time you don't tell us anything about those species, what "our neighborhood" is supposed to mean, etc. So what exactly are we supposed to be suggesting when you don't offer us any information? $\endgroup$
    – AndreiROM
    Aug 5, 2016 at 13:10
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    $\begingroup$ You would need to give us a list of technologies used by both type II humans, and type III aliens, are they just big in scale or has their mastery over energy improved ? Does FTL exist ? Can they harness energy from super massive black-holes ? What sort of weapons do they have ? How did they not detect us, yet were able to detect them ? How do we know it is a full fledged war ? Do we have a strategic position ? Are they fighting for our spiral arm ? $\endgroup$
    – Chinu
    Aug 5, 2016 at 13:19
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    $\begingroup$ @Chinu I don't think we can dream of the weapons and technologies of a Type III civilization $\endgroup$
    – kingledion
    Aug 5, 2016 at 13:42
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    $\begingroup$ Given we can't do a thing about the weapons, I believe a "diplomatic and political approach" (as mentioned in the question) requires information on the diplomacy and politics (psychology) of the type III civilizations. Different civilizations would require very different approaches. $\endgroup$
    – Ghotir
    Aug 5, 2016 at 13:44
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    $\begingroup$ I view the usage of the Kardeshev scale to be completely worthless as Energy consumption doesn't strictly follow tech progression, because a high tech society could just use low energy devices and a low tech society could just use high energy devices and there be a lot of them. For all intents and purposes we could be a Type 3 civ if we allow for space travel and enough generations to pile up without advancement. So it could range from we could totaly decimate them to there is literally nothing we could do since we could imagine nor know what they're doing or what ills it could inflict on us. $\endgroup$
    – Durakken
    Aug 5, 2016 at 16:41

6 Answers 6


The best the K2 civilization can do is to attempt to shield themselves from collateral damage caused by whatever the aliens are using. This is problematic since they could be using principles and physics which have not even been discovered yet by the KII civilization. In that regard, the question is somewhat like asking what effective steps Knights could take to defend against smart bombs and 100kW laser weapons.

Since we have no real understanding of the aliens, their motivations or war aims, virtually any strategy or tactic that could be devised becomes meaningless. We have literally no information to work with outside of initially inexplicable goings on in the local stellar neighbourhood, which could even include such events as suns being destroyed by single "shots" of energy directed from outside of the galaxy.

Even trying to describe what is happening is virtually impossible to contemplate. The closest SF writer that I can think of is Steven Baxter's Xelee sequence of novels, with FTL/Time travel weapons, black hole "guns" and other exotica.

The other issue which hasn't been touched on yet is just what sorts of physics are in play? If the aliens are restrained by General and Special relativity, then the Andromeda Galaxy has been targeting and firing based on information 2.5 million years old, and the results of their actions will become visible 2.5 million years from now. If they have FTL technology, then they also effectively have time travel, which has many issues of its own, including the ability of either party to effectively erase us from the timeline either by accident or on purpose.

The only remotely realistic response to this is for the KII civilization to scatter and disperse their civilization across the home galaxy and the globular clouds orbiting the galaxy (at 40 kiloparsecs from the galactic core, you should be safe from most collateral damage). This could be considered the "cockroach" strategy, be widely dispersed and capable of feeding of the detritus of the war and whatever local resources come to hand. The splinters of the KII civilization which make it to the globular clusters will at least have tens of thousands of stars in close proximity, which will allow them to grow to a K3 civilization with the available energy, in case they get sucked into the war.

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    $\begingroup$ As this answer has suggested, an agricultural civilisation capable of fielding knights would be significantly less than 1 Kardashev scale below modern day humans. $\endgroup$
    – March Ho
    Aug 6, 2016 at 11:00
  • $\begingroup$ ". In that regard, the question is somewhat like asking what effective steps Knights could take to defend against smart bombs and 100kW laser weapons." You definitely haven't read "The high crusade" by Paul Anderson. :D $\endgroup$
    – mg30rg
    Aug 8, 2016 at 11:57
  • $\begingroup$ then they also effectively have time travel only if the understanding of physics by the KII is correct. $\endgroup$
    – njzk2
    Aug 8, 2016 at 12:38
  • $\begingroup$ Pretty sure that our own K.7 civilization already understands this concept, we just can't enact this. $\endgroup$
    – Thucydides
    Aug 8, 2016 at 13:09
  • $\begingroup$ Ethyopia vs. Italy. Your analogy in the first paragraph is flawed (or, for more scifi example, see Dune). $\endgroup$
    – user4239
    Aug 8, 2016 at 18:01

We can examine what a full K-type "difference" looks like in the current context. While we cannot look up yet (there are no K-type 1.7+ civilizations as far as we can see), but we can look down.

Humanity is K-type 0.7 as of 1973, and since then has added rounding error. So we are talking about what a modern industrial war looks like to a K-type -0.3 civilization.

Negative? Yes, K-type is logarithmic. According to Carl Sagan, it works out to:

$$ K = \frac{\log_{10}{P-6}}{10} $$

Where $P$ is power in watts. Solving for $P$ we get:

$$P = 10^{10 K + 6}$$

or our K-type negative 0.3 civilization has a $P$ of 1 kilowatt. 24 kwh/day.

Now, photosynthesis is about 11% efficient, and the sun deposits about 4800 watt-hours per sq. meter per day. Thus photosynthesis captures 528 watt-hours per square meter per day.

To generate sustained 1 kilowatt of power, that requires 24 kilowatt-hours per day, so 45 square meters of photosythesis.

Supposing a civilization turns this plant matter at a 10% efficienty to useful work (via feeding humans or work animals, and their thermal efficiency). Then you need a civilization with the equivalent of 450 square meters of plant life under intensive cultivation. (This assumes the energy of "keeping humans alive" doesn't count. If it does, the civilization looks more like a single family on an island eating local fruits, living in a cave, and with no access to boats.)

Suppose we have a hunter-gatherer society on an island that uses 0.5% of its land area as efficiently as intensive crops, and gets 2/3 of its calories from fishing in the water. Then an island of 30 square km with hunter-gatherer agricultural intensity would be K-type -0.3 civilization, roughly.

So Nauru island pre-colonization, or roughly North Sentinel Island today. At most a dozen or few people whose primary power source is mostly wild plants and animals.

To reframe your question: as such a civilization, how do they protect themselves from a shooting war between the (current era) USA and an equal strength superpower foe?

In that scenario, if there is a war nearby, the superpowers will accidentally completely destroy your culture. Even if no weapons hit you or come close, and they are fighting a limited war, if some random excess supplies are aquired their value could exceed your entire economic output of your civilization for as long as you have recorded history. If they use your area as a minor base, more people than your entire civilization will travel through your area, you will be powerless to prevent them from doing anything. They could show up and build something more impressive than your entire civilization's stored capital (and technology level) as a throw-away base in a matter of days, then leave random detritus behind; the parts of the detrius you understand (a small fraction) still exceed your civilizations productive capacity by an order of magnitude or two. What use you could figure out of their tools would be like someone working out how to bend and shape a computer laptop's metal case to form a better spearblade than a bamboo and curt spear.

They may seem to sometimes be interested in economic transactions, but they are doing it like a US serviceman might do it with a local on one of the islands. Individuals casually offer to do something at the limits of your civilization's capabilities (like terraform an entire planet, within the limits of a K2 civilization) for some arbitrary price that you see no use for (get about a million people to all jump up and down 17 times exactly while picking their noses in the next hour in a particular city on a particular planet). After you arrange it, they forget to get around to it; when asked, they laugh. A week later they instead deliver 2 complete and new terraformed planets in a harmonic orbit, each mirror-copies of the other, leaving the old one alone. You have no idea how they got there.

Your super-weapons can dismantle planets. Their super-weapons can dismantle stars and wipe civilization over 100s of light years, and their normal weapons turn the planets of a solar system to dust. Using a different analogy, imagine USA defending against a civilization whose infantry rifles shoot megaton explosives, and the infantry survive the back-blast.

Your civilization has managed to encase a single star in computronium at a low density. Jupiter is being dismantled. The sun has been harnessed for its energy efficiently, and you have started colonizing nearby stars. Their large ships are AU or Lightyears in size (mobile battle platforms: no more space ships than a nuclear aircraft carrier is a canoe, not physical objects as much as arrangements of fields), and have populations 10 to 100 times larger than your entire civilization.

The odds are against any one of these "large ships" actually coming anywhere near your civilization. A small billion+ sentient temporary base might set up. They'd evacuate your inner solar system, dismantle 10% of your sun, and build a "supply depot". Small fast ships (AU in size) may stop by for resupply. One of them smashes into Jupiter (possibly a navigation error?). Jupiter loses 30% of its mass, scattering debris throughout the solar system and killing trillions directly and indirectly. The alien ship survives, repairs, and leaves. A week later, another ships cleans it up, builds a new gas moon of Jupiter from the loose debris, and smashes together two of the moons, then cools off the resulting location and provides it with an atmosphere and new terran-compatible programmable biosphere complete with beanstalks, but with no creatures from Earth on it.

They speak to you, and you think they are asking if the new planet would help, and sorry for the mess.

There is no protection at your energy scale. You cannot run, you cannot hide. They don't have to engage in malice to destroy your entire civilization: even casual interaction might do it. All it takes is that they are desperate enough not to treat you with extreme kid gloves and stay away from you for your civilization to be utterly changed, and if a shooting war starts anywhere "near" (where "near" could include distances farther than members of your civilization have explored and returned) you are paste or not based on factors you cannot comprehend.

In short, you can survive through luck. Such a war is, in Ian Banks parlance, an outside context problem: your civililization lacks the experience and tools to even know what the safest thing to do is.

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    $\begingroup$ Interesting, you describe the cargo cult. $\endgroup$
    – JDługosz
    Aug 6, 2016 at 15:04
  • $\begingroup$ @JDługosz wikipedia who claims to have gotten it from Sagan. Basically, 10^16, 10^26 and 10^36 are decent approximations of the Wattage available for K1 2 and 3 civilizations. So $K = \frac{\log_{10}(P-6)}{10}$ falls right out. $\endgroup$
    – Yakk
    Aug 6, 2016 at 15:07
  • $\begingroup$ I updated your post to include that. Notice how I used a more targeted link to the right section, and worked the attribution in-line $\endgroup$
    – JDługosz
    Aug 6, 2016 at 15:13
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    $\begingroup$ @JDługosz I suspect that our 200 years of "scientific disipline" being extrapolated to being able to understand the mental processes or types (not just ways) of manipulations of the universe a civilization many millions or billions of years old whose technology works on near-cosmic scales might be over confident. Sure, the K2 is "most of the way there", but you are extrapolating from us to the K3 as being "us, just with more power". I find that unlikely. $\endgroup$
    – Yakk
    Aug 6, 2016 at 15:28
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    $\begingroup$ +1 for Reference to Ian Banks. This seems to be a major plot device in his novels. $\endgroup$ Aug 9, 2016 at 15:15

Do rats care about human war? Other answers have focused on powerlessness and how the Ⅱs may be accidently trampled by the Ⅲs, as (Zibbobz points out) like the source of the expression of mice and men. But I want to focus on the idea that this presents a background that’s no different than any uncontrollable nature.

The rats avoid the battles, and then find a niche in the environment caused by the conflict. Burns’ wee beastie was nesting in the human’s cultivated field because that’s where the food is: a hugely dense source of higher grade food than anything found naturally. While not every individual goes unscathed, the mice and rats have made a niche for themselves following human activity, and also spread over the world and prospered as a species.

Maybe your K-Ⅱ will “cargo cult” the Ⅲs. (See Yakk’s answer for a detailed analysis of this!)

Birds follow human farmers plowing a field. Maybe the battles and other infrastructre-related activities will provide opportunities for the K-Ⅱ to exploit. From their point of view, the K-Ⅲ’s activities are no different than any other uncontrollable background.

They just have to avoid becoming pests. The Ⅱ should exploit the background they find themselves upon, but stay below a threshhold of being noticed and exterminated; or find symbiotic or benign roles. A farmer will care deeply about mice getting into the grain store, but a family doesn’t care about the ants that clean up the litter they left after having a picnic, and the family’s younger members may even throw bread to the birds.

Humans did not want the Norway Rats to join them on their sailing ships, but the housecats were invited. The Ⅱ might adapt themselves to a niche that one or both of the Ⅲs welcome, perhaps to deal with other Ⅱs that have gone the pest route.

The bird following the plow I mentioned earlier: if it’s picking up what the farmer is sewing, it may end up being dinner for the farmer or killed just to stop it from interfering. But if the farmer is turning over the previous crop and exposing worms and grubs and deeply burried tender roots, he won’t care about the birds picking at it. The successful bird is the one that knows the difference. If the birds go after burried larva that would have eaten the new crop, then they might be welcomed by the farmer and rewarded in addition to being in a symbiotic niche.

This has been explored in fiction before. The Men in the Walls comes to mind, but it’s not on the scale of the OP. The background of Stephen Baxter’s Xeelee Sequence is close: Cultures are divided on whether to interfere with the activities of a super civilization or assume that they know what they’re doing and leve it alone. Flux for example concerns an entire civilization, “fallen” from the colonists who adapted life to exist inside a neutron star in a gas of superfluid neutrons. The whole colonization effort (long forgotton by their descendents) was for a single shot in the war, engineering the neutron star to mess up some other megastructure of cosmic string.

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    $\begingroup$ Rats not caring about human wars is more of a lack of sentience thing. See - "To a Mouse, on Turning Her Up in Her Nest with the Plough" $\endgroup$
    – Zibbobz
    Aug 5, 2016 at 19:57
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    $\begingroup$ Despite the fact that the OP specified there was a war between K2 aliens doesn't mean K2 humans would recognise it was a war. It could resemble a chain reaction of astronomical catastrophes.. The OP's scenario resembles the Pacific War's affect on the island societies in Oceania. $\endgroup$
    – a4android
    Aug 6, 2016 at 5:25
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    $\begingroup$ Exactly. (But you meant K3 in the first usage) It might also take place on a longer timescale. $\endgroup$
    – JDługosz
    Aug 6, 2016 at 13:10
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    $\begingroup$ Well spotted. Yes a K3 war. Longer timescales would be the norm in a relativistic cosmos. No-one has mentioned economic or cyber warfare between K3 aliens. More advanced aliens might wage more advanced forms of warfare. Nothing we would recognise as warfare. $\endgroup$
    – a4android
    Aug 7, 2016 at 5:56
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    $\begingroup$ @a4android Read it again! $\endgroup$
    – JDługosz
    Aug 8, 2016 at 11:39

Here is some perspective. Human power consumption is 1.23e13 W or 3.87e20 J/year. An 1 Megaton nuclear weapon goes pop with 4.2e15 J of energy, or 5 orders of magnitude less than our yearly consumption.

A type III civilization can harness the power output of a galaxy, or 4e37 W = 1.3e45 J / year. At the same ratio of power, an alien super-weapon would hit with 1e40 J of energy, just shy of the binding energy of the sun, or in more stark terms, greater than the energy released by converting the entire moon's mass to energy.

So these aliens can one-shot our sun. What are we going to do to stop them, even at Kardashev II?

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    $\begingroup$ Exactly. I mean … if they are fighting war on a galactic scale and throwing supernovae around like cannon shells all Life in our system could be destroyed without them even noticing. $\endgroup$
    – Michael
    Aug 5, 2016 at 18:18
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    $\begingroup$ Except your supposition assumes that a civilizations ultimate weapon power is a function of their yearly power consumption. There is no reason to come to this conclusion. You are coupling to arbitrary metrics. It makes no sense at all. $\endgroup$
    – Scorb
    Aug 6, 2016 at 2:41
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    $\begingroup$ @ScottF: Power consumption is the only thing we know for certain about KⅢ civilizations by definition. Of course this huge power consumption could be mostly due to an increase in population and settlements, but I think their machines and weapons would be on roughly the same scale. $\endgroup$
    – Michael
    Aug 6, 2016 at 7:03
  • $\begingroup$ To add something to the point about power, who says the KIII's can't be the KII's tech level just covering the galaxy? Superweapon power would be unlikely to be linear at all. $\endgroup$ Aug 19, 2017 at 6:26

"Safeguards" is impossible. A type II civilisation cannot meaningfully threaten or bribe a type III civilisation: they can take anything they want from us without our being able to do anything meaningful about it.

If the civilisations are "civilised" in the sense that they try to avoid unnecessary destruction, then they might leave us alone if we ask nicely. If, however, either of them glories in destruction of the weak, drawing ourselves to their attention just gets us killed faster and more thoroughly.

They are aliens, not humans. This is why knowing more about the type IIIs is vital to formulating any kind of strategy.


How advanced their computing capabilities are?

If they are as ahead in computing department as in energy department, whatever tactics you devise would be transparent to them because they can simulate your whole civilisation reliably enough.

If all of you prefer to live in the world where more advanced agents play nicely with less advanced agents, you only need to be of no military interest to either side and hope that day will not come when your atoms could be used in some promising attack. Luckily, your civilisation is too weak to bother with.

Dispersing - just in case - looks fine.

Also, if you have some reasonably sure means of destruction, you could try looting stuff that is obviously garbage for them but is good enough for you. Asking both sides just in case would be nice too.

Make sure to equip your storages with some self-destruction devices - if you've claimed some stuff then there's no point in trying to get it from you. Sure, you can not defend it, but you won't give it away either.

For concievable example, 100 tons of scrap metal dispersed over some large area is a thing not worth bothering with, same 100 tons of scrap metal in one storage is a somewhat of an asset.


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