So, if Humanity wants to conquer the galaxy one star at a time, it is going to need a massive fleet. This fleet will require massive resources to build. If I want to build a fleet to take over the next star (even if it's just a couple generation ships), Wouldn't we need more resources than are available on Earth?

In our system alone, What would we build our starting fleet out off? And where would we gather the materials from?

Assume that all of humanity has magically united in this goal and will do everything in it's power to do so. If no other life exists, we will just settle the galaxy. If other life exists, they will serve us by force or be destroyed! (HAIL KIBIA!)

Bonus if you can also answer for continuing to build up the fleet with resources near OTHER stars (though I think that will be a follow up question)

  • 4
    $\begingroup$ When you say 'conquer' and 'take-over' do you mean 'settle' and 'settle'? $\endgroup$
    – kingledion
    Nov 2, 2016 at 16:47
  • $\begingroup$ Do you have an unlimited budget (e.g. earth dictatorship) or a constrained one? Is your conquest for military, ressource gathering or settling purposes? $\endgroup$
    – PatJ
    Nov 2, 2016 at 16:50
  • $\begingroup$ @kingledion and PatJ Yes. Updated question to clarify. $\endgroup$
    – Tezra
    Nov 2, 2016 at 17:02

4 Answers 4


The asteroid belt

The asteroid belt has about 3e21 kg of mass. About 10% of those are metal rich M-type, 15% silicate rich S-type and 75% carbonaceous C-type. Between them they have all the material you could possibly need to create a space fleet.

I leave as obvious the assumption that if we can send a generation ship to another star system, we can get to the asteroid belt and build some factories there.

The asteroid belt should provide plenty of materials to get to many other star systems. An aircraft carrier weighs in at about 1e8 kg and fits 5,000 people for long durations (though not decades). If you assume a colony ship is a million times larger (1e14 kg) you can still make at least a million colony ships out of the asteroid belt.

Then if you get to another star system, and there is an asteroid belt there, you can keep making more.


To put a different spin on things, you don't even have to leave the Solar System to conquer the Galaxy; just create a Nichol-Dyson beam and start vaporizing offending planets from light years away. With a bit of retuning, the beam can then be used to launch giant lightsails to target systems at a high percentage of c if needed.

The other main method of rapid conquest (well, relatively rapid) is to send "Von Neuman" machines. This can actually be complimentary with using Nichol-Dyson beams to propel them through space. The Von Neman machines can enter the new solar system and immediately begin converting matter and energy into a new generation of machines and launching apparatus. Any beings in the new solar system will simply be converted along with everything else (which covers conquest).

It is estimated that even at a slow progression of 10% of the speed of light, a wave of Von Newman machines could cover the entire Milky Way galaxy in @ 10 million years (this, by the way is the source of the Fermi Paradox: any reasonably advanced species should have been able to visibly colonize the galaxy, and we would have unambiguous evidence of their presence).

So conquering and colonizing the galaxy is quite possible, and even can even be done on a relatively quickly (on astronomical scale) without even having to leave the solar system (if eliminating all aliens is the goal).

  • $\begingroup$ Nice, but the question is really just justifying/how of building my first fleet. Nanites are boring. I need realistic origin stories for my space-operas. X3 $\endgroup$
    – Tezra
    Nov 2, 2016 at 18:48
  • $\begingroup$ @Tezra no nanites here, in this answer. Or you seeking for steam punk answers, because steam is a fun, everything else is boooring )) $\endgroup$
    – MolbOrg
    Nov 3, 2016 at 2:12

Our solar system is teaming with asteroids which contain very valuable materials. Even if that were not the case, there's the planet Mars, and it's moons that we could mine.

In actual fact, the availability of materials is not a concern.

It's getting to them, and more importantly, making it economically viable to extract, process, and ship them to their destinations.

  • 1
    $\begingroup$ This response just made me start laughing when I thought of some middle manager scrambling for materials to finish his project, and noticed that Mars was just sitting there, unused. $\endgroup$ Nov 2, 2016 at 20:05
  • $\begingroup$ @marshalltigerus - well, it is just sitting there. $\endgroup$
    – AndreiROM
    Nov 2, 2016 at 20:17
  • $\begingroup$ down at the bottom of a well. $\endgroup$
    – user25818
    Nov 2, 2016 at 22:06
  • $\begingroup$ @MarshallTigerus do not tell him about Jupiter mining, before you get squad of paramedics nearby. $\endgroup$
    – MolbOrg
    Nov 3, 2016 at 2:07

Wouldn't we need more resources than are available on Earth?

Yes and No. But if you mean a planet, it depends on which planet. But in general we have plenty matter in the solar system and for you initial fleet it will be more than enough, even Earth resources. You can send all 10 billion of people from earth into interstellar conquest using Earth available resources, without even making a dent in its resources, but probably you will kill all animals and live on that planet during the process, but the planet itself will be perfectly intact.

In our system alone, What would we build our starting fleet out off?

Build it out of carbon. CNT's and that all.

And where would we gather the materials from?

Venus - 1.31e+20kg of carbon, atmosphere
Jupiter - about 1e24 kg of carbon
The Sun - plenty of carbon

Bonus if you can also answer for continuing to build up the fleet with resources near OTHER stars


The most common answer seems to be that there are 100 billion stars in the Milky Way on the low-end and 400 billion on the high end. But I’ve seen even higher numbers thrown around.

It has to be done that way, just because you do not have enough people, and each time to return to earth and dig for its resources to continue galaxy conqueror, is hmmm a slow process?

There will be carbon same way as here. It is everywhere in our galaxy. There will be gas giants same as here, maybe not in each system but one system per million(and we already know it is a better ratio than that) is enough.

As a note: More generally you have to read about space habitats, it will improve understanding of the problem, anyway, you may need them if you are ok with generation ships.


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