In most 4x games, almost every space nation fights for star systems, planets, black holes, etc. The benefits are obvious: planets to colonize or mine from, solar energy, strategic positions and so on.

Now lets turn that concept on its head: why would these space nations be interested in completely empty space, far from any planet or star? Why would they value it as much, if not even more than star systems? What could they find there?

I can think of a couple strategic reasons myself:

  • Matter / gravity disrupts Hyperspace lanes and exits, meaning that using them is only possible far away from any star systems.
  • Jumpgates allow for instantaneous travel between them, but also become a massive weak point in a war. If one blows up, the explosion could destroy a whole system - so placing them far outside of star systems would be safest.
  • Sensitive sensor arrays meant to secure borders work much better without too much space dust or asteroids flying around.
  • Some science research that requires less gravitational interference.
  • No intergalactic rules apply here, allowing for the deployment of minefields.
  • Some sort of vacuum-based energy generation?

(I just assume that empty space far away from celestial bodies has less gravitational interference - but I may be wrong!)

While the above reasons may push a space nation to want some empty space, it wouldn't really motivate anyone to go far beyond their own borders. Especially considering that there's more vacuum than stuff out there, so there's more than enough for everyone.

Another issue is, that I want them to be more interested in empty space between star systems - not "above" or "below" them. Almost as if space would be treated as semi-2d plane - but I can't come up with a good reason why that void would be better than any other void.

What other things could possibly motivate nations to engage in wars for essentially empty space between systems?

  • 1
    $\begingroup$ Do people want empty space or the empty space immediately between two stars? $\endgroup$
    – neph
    Commented Sep 23, 2021 at 20:48
  • $\begingroup$ @neph preferrably, the empty space between two stars or celestial objects in general. Otherwise, those nations could all just go "up" or "down" infinitely, making any conflict about it meaningless (the disadvantage of having a third dimension...) $\endgroup$
    – Katai
    Commented Sep 24, 2021 at 8:11
  • $\begingroup$ Sounds like a navy or a merchant federation. Whoever controls the solar systems controls the production, whoever controls the space between those systems, controls the distribution. $\endgroup$ Commented Sep 24, 2021 at 10:01
  • $\begingroup$ Space is huge, making people fight over something so gargantuan and growing is hard. $\endgroup$ Commented Sep 24, 2021 at 20:06

11 Answers 11


The Electric Universe people were right. There are plasma filaments connecting all the stars, carrying incredible amounts of electric current. Only between the stars is it possible to tap into that energy, so the areas in the middle of the filaments are hotly contended.

  • $\begingroup$ Damn, that's actually a really good way to solve both of my problems - would explain why they are only interested in empty space between the stars, not above or below them! $\endgroup$
    – Katai
    Commented Sep 24, 2021 at 8:08
  • 3
    $\begingroup$ Just as the Earth has van Allen belts deflecting the solar wind, the solar wind in turn deflects what I will call interstellar winds (Electric Universe). Voyager just left the solar system and mapped the rise in radiation level. $\endgroup$
    – Peter Wone
    Commented Sep 25, 2021 at 0:39

Energy generation

In the vastness of space there is something. We don't know what it is or how to see it, but we can see it's effects. It pushes whole galaxies apart, while seemingly invisible. This is dark energy. There is a great abundance of it to be so powerful and most is likely in the vast emptiness of space between star systems and galaxies.

Stars, planets and black holes all can make a ton of energy for a space nation. Yet when they found out how much energy you can make with dark energy, it made the rest practically obsolete.

The power can also help travel. For the same reason dark energy is pushing everything father apart, so it can be used for high speed travel, potentially FTL. All you need is the dark energy residing in the vast emptiness of space. Go there and start harvesting!

  • $\begingroup$ In light of the "empty space between star systems" constraint, I'd suggest modifying this to say something like "the gravitational interactions between the hundreds of billions of stars in the galaxy is the generating force for this mysterious substance. Though incredibly diffuse and generated only slowly, gravitic collector ships are able to sweep vast volumes of space efficiently enough to provide economically viable quantities, making controlling as much interstellar void as possible for harvesting the basis for a star-nation's wealth and power." $\endgroup$ Commented Sep 23, 2021 at 21:34
  • $\begingroup$ Actually, dark energy has an extremely low density compared to regular matter, making it less desirable. 7 gram of regular matter have the same energy density than dark energy in a total volume of 1e15 km³. $\endgroup$ Commented Sep 24, 2021 at 7:48
  • $\begingroup$ @NereidRegulus uranium has more energy density than gasoline. Doesn't mean gasoline is useless. With dark energy 68% of total energy according to some estimates, it can be preferable to use this instead of any other. It can also be more efficient. To harvest this, you need the vast emptiness of space. Finally, you might be able to pack dark energy much tighter after harvesting than anything else. It's a theoretical energy. As we don't know exactly how it works anything goes. $\endgroup$
    – Trioxidane
    Commented Sep 24, 2021 at 8:45
  • $\begingroup$ "In the vastness of space there is something. We don't know what it is or how to see it, but we can see it's effects. It pushes whole galaxies apart, while seemingly invisible." This would be a great sci-fi hook for your universe if it weren't taken. I wonder how many choose astrophysics majors because of this? $\endgroup$ Commented Sep 24, 2021 at 19:59

Vast voids which are devoid of gravity, particulate and radioactive interference are the perfect place to grow the flawless crystalline structures needed for the post-singularity level artificial intelligences. The computing power of any AI is strongly correlated to the size and purity of the circuitry that it lives in.

Every supreme intelligence at the heart of every star empire is constantly expanding its hardware, integrating newly grown chips into its hosting platform so that it can grow ever smarter.

To fail to grow faster than your adversaries is to fall behind in the only race that matters, the race to Godhood, to supreme mastery of all that is. Any empire which fails to control the majority of the best crystal growing voids is destined to die at the cybernetic hands of the empire which holds those voids.


By far the best natural resource is to be found in empty space is emptiness.

  • The French tested nukes in the Algerian desert. Americans decided to nuke their own desert. Apparently deserts are fun to nukes. Well empty space is the desert of the universe. You can test all sorts of weapons, maneuvers, and other schemes far from prying eyes, and far from something you don't want to accidentally damage. You can also isolate the influence of celestial bodies out of the equation, which is useful for testing and for science.

  • You can discard a bunch of junk that you never want to see again. You could do that in orbit of your planet or star, true, but if you have a lot of space-activity you run the risk, however small, to collision with space debris. If you discard them in the middle of nowhere, the risk becomes zero because nobody (that matters at least) goes there. And since it's so far away from the public eye, it's like it never happened. There is of course no equivalent in the real world for rich people/nations discarding their junk into empty spaces. None.

  • You can discard a bunch of people that you never want to see again. Space-Alcatraz! Again, you could have a space-prison around your planet or star, but that's within reach for a daring breakout. Successfully escaping becomes much more difficult when you're in the intergalactic void. Which means any attempt will have to be even more daring! And if there's anything you don't want, it's your prison break stories to be average.

  • $\begingroup$ >far from prying eyes </br> Anyone with a telescope can see, but an easy fix is to wrap everything in a huge aluminium ball. 10 or 100 AU should do just fine, depends on how big you want your sandbox to be.</br> >You can discard a bunch of junk that you never want to see again</br> Not really. Every space shot fired will hit something eventually. Every turd flushed down the space toilet will eventually kill a man. If you want to get rid of trash you can chuck it into a black hole or star. In the latter case you can re-extract it later so it amounts to recycling. $\endgroup$
    – Pipi Caca
    Commented Oct 5, 2021 at 17:48

Matter generation

What we think of as empty space is full with activity. Thanks to fluctuations of the quantum field virtual photons pop in and out of existence, one positive and one negative, which cancel each other out. With light these can be turned into real photons, which means you can create something out of basically nothing.

Uf you push this real quantum physics to the max, you can influence the field to your benefit. You can push the virtual particle pair to start far apart from each other, as well as making them much bigger. Then you turn the virtual particles into real particles and voilà! You've created actual matter. With full control you can create any molecule you want. Possibly even any material if you control a lot of molecules at the same time in a certain position.

Matter also means energy. That is what the E= mc² is all about. It means that in any mass there is an absurd amount of energy. Creating matter thus is the same as creating energy.

You need the vastness of empty space to truly control it. As little interference as possible, as the fluctuations of the quantum field are hard to control. Any unexpected particle of dust can throw the machines off, so you need the most near perfectly empty space away from anything else you can muster.

  • $\begingroup$ Photons are light, and neutral. The virtual particles you mean are electrons (and positrons), besides others. $\endgroup$ Commented Sep 25, 2021 at 1:18

Hiding valuable assets

In a sufficiently populated galaxy, there could be countless potential threats and attackers in all directions, too many to keep track of or anticipate. Space is just too big.

So instead of expensive force fields and hyper-sensitive early warning systems, every civilization will locate important installations in large regions of empty space and simply have it go radio silent.

It would be futile for a hostile alien race to search such a vast region of space and so, your species' embryo bank, or ultra-rare exotic mineral or whatever remains safe. Safer than with traditional shielding or military protection, without any of the cost or energy needs.

This would be a sensible way to protect any asset that may be a target of attack, and all you need is to securely record the coordinates if you need to reach it later.


Computation is more efficiant at lower temperatures


So lets just say you are running tons of simulations you might want to get as far away from a heat source you can


Shipping lanes

You can tax people for going through your "trade route", which has been done for centuries here on Earth. Set up space buoys to warn people they will have to pay a toll, or not, then enforce the toll. Not many governments would care about empty space, so they aren't going to war over the toll. They'll just go around it.

Well, that is until the volume of the tolled space becomes too large, then they either give up and pay the tolls, or go to war, and not many politicians would go to war telling their constituents that it's because of empty space they don't want to pay a toll for.

Bragging rights

Since there's nothing in these spaces, you can take them over pretty easily. Then you tell your peasants citizens about how much you've conquered during your reign time in office.

We've expanded our empire 3x since I was "elected" just 20 years ago.

Of course, the expansion has holes in it where actual solar systems exist and are run by other governments.

Space junk

There's a ton of resources "just laying around out there". You can mine nebulae, asteroid belts, or whatever else is floating around without any obvious "land rights" to them.

Of course, unless you have super cheap fuel/reaction mass, massive cargo ships, and extremely fast shipping, mining from even outside your own solar system is going to be slow and expensive to the point where anything you recover is going to cost you more to get than it's worth and be months/years in travel time. And mining within your solar system will be far easier, cheaper, and faster, so it's just another political ploy to distract the masses.


I think the biggest advantage of empty space, is that it is empty space. Obviously, it is not actually empty, as most space has some amount of stuff in it like very dissipated hydrogen gas.

That being said though, empty space is important, as especially deep space, in-between stars, is lacking in interference. Interference takes all sorts of forms that you would want to avoid. Perhaps it is gravity from nearby bodies. Maybe you have very radioactive spacecraft that you want to keep away from earth or other inhabited worlds.

In the context of an interstellar civilization, empty space is a place where other people will not be bothering you. Considering that crossing interstellar distances, you don't really have the opportunity to stop if you pass something interesting, putting a base of government or criminal origin out in the middle of nowhere would be beneficial.

You see something like a space pirate lair "hidden" in the midst of some asteroids, but considering that asteroids are valuable for mining and colonies, if you want to be left alone, they probably aren't the best place. Taking an asteroid out into empty space perhaps, but unless your interstellar civilization has just left a bunch of asteroids somewhere alone, because they haven't reach out that far, or are just swamped with resources, you'll want such hidden bases out in deep space.

Considering the breadth of sci fi topics his channel covers, I'd recommend looking at the Youtube channel Isaac Arthur, as I'm sure he's done some crazy video on harvesting energy from quantum fields in deep space.


They're outlaws

A race of people who make a living via piracy, raiding, smuggling, or other illicit activity might choose to hide out in the emptiness of space. The void is so large, it's just wildly impractical for the Space Police to even try to search for them in such a large empty region. It may not even be possible to reach those regions if your FTL depends on being near gravity wells, so only the smugglers hiding out there know the tricks to reaching these regions. (A few loops around some high-mass stars or black holes to build up velocity, followed by a push into a very specific trajectory to reach their refuge - a degree or two off and you'll completely miss it and not even come close enough to know there's anything there. Almost literally "Second star to the right and straight on 'til morning".)


Stars are scary

Stars spit out all kinds of radiation, they have flares and mass ejections and magnetic disturbances, sometimes they go nova, and in any case they have all of this stuff whirling around them all the time that might end up on an impact trajectory with an inhabited planet. Some people might find living on a rogue planet in interstellar space boring (and you have to wear a really warm jacket), but it's safe and predictable.

But without any convenient planets or asteroids nearby, and without cheap solar power, they're more reliant on trade than most, so they look for places along the routes between solar systems so they can trade for certain essentials.


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