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40K isn't the only one to do this, but a number of sci-fi universes include starships that are many, in some cases, dozens of kilometres long. Your garden-variety battleship in the Imperium is somewhere in the region of 8-10km in length, with the HH series making references to ships even larger (I believe a large part of the battle in Know No Fear involves a cruiser that's about 20km long if I remember correctly?).

I've been wondering just how feasible such creations are? Not only for 40k, but also for creations which render 40k ships minute, such as the Death Star. How much material would be required to build something like this? How long? And surely once it's built it'd disintergrate under its own mass? I like the idea of gargantuan starships as big as cities, but I honestly can't imagine something like that being even remotely possible in real life.

Well, it's a space craft, so mass isn't really a problem. What is a problem is that such a ship would most likely have to be built in orbit, and can never go planet side.

Even Lexx, an organic spaceship that's designed to land on planets in order to feed, experiences some difficulty. It actually prefers to just blow up the planet and sift through the debris. Lexx is about the size of manhatten, btw.

They would require a lot of materials, but it's not that hard to acquire them. Especially when you have +100 planets to mine from.

Well... 8 to 10km is actually very large for an Imperial vessel. Most of them range 2 to 3. Of these, none of them are designed to ever enter the atmosphere of a planet. Most of them are built in space, and will forever remain in space. Their mass is irrelevant, because they're in space, and the materials to construct them are taken from planets who are dedicated to the project, sometimes being strip-mined so thoroughly that it can no longer support life, and because they are designed with a honeycomb-like structure which has all manner of internal supports, bulkheads, barriers, beams and other industrial tricks to keep it together.

It also takes the Imperium years to centuries to build one of their vessels, so it's not like they're cranking them out.

Material isn't really an issue if you can fabricate outside of a gravity well. A nickel metal asteroid 5x2 miles long roughly has far more iron than the entire quantity of iron removed from the crust in the whole of human history to date. And there are thousands of those just in between Mars and Jupiter, much less the Oort Cloud.

Relativistically your mass literally increases as you approach the speed of light. It does so in such a dramatic fashion that the difference in mass between a corvette and an aircraft carrier becomes trivial. If you can survive the forces at all, then you have the technology to basically build whatever you want.

In all I'd say the scale makes sense given the hand-wavium that is allowed in terms of energy generation and propulsion.

 Silverthorne wrote:
Material isn't really an issue if you can fabricate outside of a gravity well. A nickel metal asteroid 5x2 miles long roughly has far more iron than the entire quantity of iron removed from the crust in the whole of human history to date. And there are thousands of those just in between Mars and Jupiter, much less the Oort Cloud.

Relativistically your mass literally increases as you approach the speed of light. It does so in such a dramatic fashion that the difference in mass between a corvette and an aircraft carrier becomes trivial. If you can survive the forces at all, then you have the technology to basically build whatever you want.

In all I'd say the scale makes sense given the hand-wavium that is allowed in terms of energy generation and propulsion.

However, more rare elements that might be necessary to facilitate particular alloys are not necessarily so common. You could make baser metals, but the 'unobtanium' metal hull might not be so easy. Most asteroids and similar materials do not contain elements high on the periodic table of elements, or at least not in large quantities.

Rare Earth minerals that we use to build things like electric cars are not simply +100 common in space, as most of those objects lacked the necessary set of steps to generate even terran amounts of limited quantity materials.

 Maniac_nmt wrote:

 Silverthorne wrote:
Material isn't really an issue if you can fabricate outside of a gravity well. A nickel metal asteroid 5x2 miles long roughly has far more iron than the entire quantity of iron removed from the crust in the whole of human history to date. And there are thousands of those just in between Mars and Jupiter, much less the Oort Cloud.

Relativistically your mass literally increases as you approach the speed of light. It does so in such a dramatic fashion that the difference in mass between a corvette and an aircraft carrier becomes trivial. If you can survive the forces at all, then you have the technology to basically build whatever you want.

In all I'd say the scale makes sense given the hand-wavium that is allowed in terms of energy generation and propulsion.

However, more rare elements that might be necessary to facilitate particular alloys are not necessarily so common. You could make baser metals, but the 'unobtanium' metal hull might not be so easy. Most asteroids and similar materials do not contain elements high on the periodic table of elements, or at least not in large quantities.

Rare Earth minerals that we use to build things like electric cars are not simply +100 common in space, as most of those objects lacked the necessary set of steps to generate even terran amounts of limited quantity materials.

And that is why mining and forge worlds exist. To get those minerals.

I don't think they have ever described what Adamantium is, which seems to be the most common metal used in armor and armament. I assume that more exotic elements are created by fusion of more mundane metals. Thereby both generating the power necessary to power the shipyard and the materials necessary to build the hulls. That is how I would do it, anyway.

This discussion makes me think about the Nid fluff and facepalm. Necron fluff is obnoxios but Nid fluff just doesn't even try to be within lightyears of realism.

as the above poster said you'd just have to mine for the more unusual stuff if you can't produce it industrially somehow. They might have the technology to track ancient supernovas and predict areas of the galaxy where super heavy stars exploded, creating a goldmine of heavy metals.

This Makes me think two things:

1) The heavy armor and other exotic elements that are used for ships could easily be explained as something produced through means even the imperials don't understand anymore.

2) Imperial (and actually all races but Tau) ships never get close to light speed. That's why they use the warp, to circumvent coming up with FTL travel and time restrictions.

Your #2 point is actually spot-on. Most races circumvent FTL issues via the Warp or the Web-Way. The exception being the Necrons.

It's worth noting that the Battlefleet Gothic rulebook does make a few comments on this. Within the game, ships usually have to move a minimum distance each turn, as you normally cannot bring such a large ship to a complete stop too quickly, due to inertia. You cannot simply put the engines in full reverse, as the front half of the ship will basically try to keep going forward while the back half is stopping. Whether or not the laws of physics agrees with this, I do not know, but that is just how BFG explains it.

In Star Trek, they use Structural Integrity Fields and Inertial Dampeners to reduce stress on the ships structure.

 Tannhauser42 wrote:
It's worth noting that the Battlefleet Gothic rulebook does make a few comments on this. Within the game, ships usually have to move a minimum distance each turn, as you normally cannot bring such a large ship to a complete stop too quickly, due to inertia. You cannot simply put the engines in full reverse, as the front half of the ship will basically try to keep going forward while the back half is stopping. Whether or not the laws of physics agrees with this, I do not know, but that is just how BFG explains it.

In Star Trek, they use Structural Integrity Fields and Inertial Dampeners to reduce stress on the ships structure.

I think that's how it works, yes. I could be wrong, but momentum and inertia should still work in space.

Oh, inertia still exists in 40K. To compensate, they just use a lot of really strong bolts. Imperial ships are built to last, that's how they remain in service for 5,000 years, sidereal.

 Silverthorne wrote:
I don't think they have ever described what Adamantium is, which seems to be the most common metal used in armor and armament. I assume that more exotic elements are created by fusion of more mundane metals. Thereby both generating the power necessary to power the shipyard and the materials necessary to build the hulls. That is how I would do it, anyway.

This discussion makes me think about the Nid fluff and facepalm. Necron fluff is obnoxios but Nid fluff just doesn't even try to be within lightyears of realism.

as the above poster said you'd just have to mine for the more unusual stuff if you can't produce it industrially somehow. They might have the technology to track ancient supernovas and predict areas of the galaxy where super heavy stars exploded, creating a goldmine of heavy metals.

That is the trick though, it requires the planet to have undergone specific formative processes to get those rare materials. The 'just mine for it' does not necessarily hold water.

All 'star trek class m' planets will not have the same elements in the same quantities on them. Particularly true in 40k when many of those 'M' planets were terraformed by some means to become class 'M'.

Iron, Nickel, Hydrogen, Carbon, all very common. As the atomic structure becomes more complex things become less common. I'm not saying in 1 million worlds you couldn't find it, rather that just having 1 million worlds isn't a guarantee of having vast access to it in spots where it can be easily transferred to a needed location to produce 'unobtanium x'.

There are 1 million worlds in the Imperium, that doesn't take into account the hundreds or thousands of mining colonies on asteroid belts, rogue planets, solid moons of gas-giants, or other "temporary" set-ups the IoM and the AdMech might have going at any moment.

The AdMech can find some pretty rare stuff... I mean, shoot, IRL, we recently discovered a planet made almost entirely out of diamond... so finding a planet that meets their needs, or at least exhibits the infra-radio-xray-emissions to indicate likely presence of the materials they are after is not so hard to believe.

 Maniac_nmt wrote:

 Silverthorne wrote:
I don't think they have ever described what Adamantium is, which seems to be the most common metal used in armor and armament. I assume that more exotic elements are created by fusion of more mundane metals. Thereby both generating the power necessary to power the shipyard and the materials necessary to build the hulls. That is how I would do it, anyway.

This discussion makes me think about the Nid fluff and facepalm. Necron fluff is obnoxios but Nid fluff just doesn't even try to be within lightyears of realism.

as the above poster said you'd just have to mine for the more unusual stuff if you can't produce it industrially somehow. They might have the technology to track ancient supernovas and predict areas of the galaxy where super heavy stars exploded, creating a goldmine of heavy metals.

That is the trick though, it requires the planet to have undergone specific formative processes to get those rare materials. The 'just mine for it' does not necessarily hold water.

All 'star trek class m' planets will not have the same elements in the same quantities on them. Particularly true in 40k when many of those 'M' planets were terraformed by some means to become class 'M'.

Iron, Nickel, Hydrogen, Carbon, all very common. As the atomic structure becomes more complex things become less common. I'm not saying in 1 million worlds you couldn't find it, rather that just having 1 million worlds isn't a guarantee of having vast access to it in spots where it can be easily transferred to a needed location to produce 'unobtanium x'.

No. The planet has jack all to do with the creation of heavy complex elements, it's just where they end up. There is zero evidence in exogeology whatsoever to indicate that any planetary accretion process favors heavy metals. Zilch. You don't get even close to the amount of energy needed to create new elements in the core. That is planetary science 101. And the abundance of elements again has little to do with complexity. Iron is far far far more abundant universally than many simpler elements. But as a fusion product it is the most stable product av super massive star can produce. Again this is like astro 101 stuff. Mining is how you get the heavier metals. They only exist as supernova products, and even then, a big supernova. Then the debris is coagulated into nebulae which eventually undergo star birth. Or don't. Or would be easier to get them, again by mining, from space debris than on a planet since chemical differentiation causes the heavier elements to sink coreward

On a slight off note: I love this topic.

 Psienesis wrote:
There are 1 million worlds in the Imperium, that doesn't take into account the hundreds or thousands of mining colonies on asteroid belts, rogue planets, solid moons of gas-giants, or other "temporary" set-ups the IoM and the AdMech might have going at any moment.

The AdMech can find some pretty rare stuff... I mean, shoot, IRL, we recently discovered a planet made almost entirely out of diamond... so finding a planet that meets their needs, or at least exhibits the infra-radio-xray-emissions to indicate likely presence of the materials they are after is not so hard to believe.

Just did some research (if using the internet counts as research ) and that daimond planet is speculation. It may or may not be carbon rich and so on. All you will see is artists impressions of it. I wouldnt count on it being true. Apparently they can also tell what planets contain life... by the frequency of the minor light flashes. Also its been "descovered" 10 years ago but doesnt matter really.

I dont want to be one of "those people" but chances are all our speculation of whats out there is so far from right people in 100 years will laugh at us.

On topic about the huge ships i think the biggest question is how many smaller ships would it take, not only to build it but to replenish supplies, ferry troops and who knows what else. So much of the space in those ships will be taken up by smaller ships in my opinion. I think they would need smaller "tow ships" to work properly to help with turning the thing or angling it into position before departure. Not sure how it works in the fluff but i cant see a huge ship with rear engines turning sharply on its own without travelling a great distance first.

 CthuluIsSpy wrote:
Well, it's a space craft, so mass isn't really a problem.

That is, unless you start accelerating. Almost every ship in popular science-fiction has to be made of exotic, hyper-resistant (carbon nanotubes? fullerenes?) materials, or they would collapse upon themselves.

Not long ago, Foreign Policy ran a short piece commenting on the fixation of pop sci-fi with drawing parallels between spaceships and boats. Of course, the article ended up derailing into an unpallatable rant linking US financial support to defence megaprojects to "bigger is better" teenage power fantasies and popular misconceptions on technology (yep, FP is not what it used to be anymore) but still it raised an interesting point: Most sci-fi authors and franchises are extremely unimaginative -and unrealistic- when portraying space transportation and combat, usually borrowing from naval history to make up for their ignorance or lack of interest in the basic rules governing space.

The problem is not exclusive of 40k. Star Destroyers, Negh'var-class Battleships, Peacekeeper Command Carriers... even Serenity, all are wrong in one way or another. At least 40k is moderately honest in this - it's space combat aspect is a direct extrapolation of age of sail naval wargames, so they designed their spaceships accordingly.

Just did some research (if using the internet counts as research ) and that daimond planet is speculation. It may or may not be carbon rich and so on. All you will see is artists impressions of it. I wouldnt count on it being true. Apparently they can also tell what planets contain life... by the frequency of the minor light flashes. Also its been "descovered" 10 years ago but doesnt matter really.

But in the 40K universe, it *will* be made of perfect diamond, and able to align with its local star just right every X number of centuries to beam a perfect laser into some relic or another that causes/prevents massive daemonic/alien incursions.

It will also be either Necron or Eldar in design, or the last remains of a Xenos culture that died out when Man was still crawling out of the mud of Holy Terra.

 Psienesis wrote:

Just did some research (if using the internet counts as research ) and that daimond planet is speculation. It may or may not be carbon rich and so on. All you will see is artists impressions of it. I wouldnt count on it being true. Apparently they can also tell what planets contain life... by the frequency of the minor light flashes. Also its been "descovered" 10 years ago but doesnt matter really.

But in the 40K universe, it *will* be made of perfect diamond, and able to align with its local star just right every X number of centuries to beam a perfect laser into some relic or another that causes/prevents massive daemonic/alien incursions.

It will also be either Necron or Eldar in design, or the last remains of a Xenos culture that died out when Man was still crawling out of the mud of Holy Terra.

haha made me smile yea makes sense. It is a cool idea when anything is possible.

 Silverthorne wrote:

 Maniac_nmt wrote:

 Silverthorne wrote:
I don't think they have ever described what Adamantium is, which seems to be the most common metal used in armor and armament. I assume that more exotic elements are created by fusion of more mundane metals. Thereby both generating the power necessary to power the shipyard and the materials necessary to build the hulls. That is how I would do it, anyway.

This discussion makes me think about the Nid fluff and facepalm. Necron fluff is obnoxios but Nid fluff just doesn't even try to be within lightyears of realism.

as the above poster said you'd just have to mine for the more unusual stuff if you can't produce it industrially somehow. They might have the technology to track ancient supernovas and predict areas of the galaxy where super heavy stars exploded, creating a goldmine of heavy metals.

That is the trick though, it requires the planet to have undergone specific formative processes to get those rare materials. The 'just mine for it' does not necessarily hold water.

All 'star trek class m' planets will not have the same elements in the same quantities on them. Particularly true in 40k when many of those 'M' planets were terraformed by some means to become class 'M'.

Iron, Nickel, Hydrogen, Carbon, all very common. As the atomic structure becomes more complex things become less common. I'm not saying in 1 million worlds you couldn't find it, rather that just having 1 million worlds isn't a guarantee of having vast access to it in spots where it can be easily transferred to a needed location to produce 'unobtanium x'.

No. The planet has jack all to do with the creation of heavy complex elements, it's just where they end up. There is zero evidence in exogeology whatsoever to indicate that any planetary accretion process favors heavy metals. Zilch. You don't get even close to the amount of energy needed to create new elements in the core. That is planetary science 101. And the abundance of elements again has little to do with complexity. Iron is far far far more abundant universally than many simpler elements. But as a fusion product it is the most stable product av super massive star can produce. Again this is like astro 101 stuff. Mining is how you get the heavier metals. They only exist as supernova products, and even then, a big supernova. Then the debris is coagulated into nebulae which eventually undergo star birth. Or don't. Or would be easier to get them, again by mining, from space debris than on a planet since chemical differentiation causes the heavier elements to sink coreward

It requires the materials to be present in the area and created during the formation of the star system of some sort. Ergo, the formation of the planet. Higher order elements tend to be less stable, not all of them, but many. This is also chemistry 101. Chemical and situational reactions create certain isotopes, as an example.

Secondly, yes, formation of the planet does cause certain characteristics. Sans a large ocean, as an example, with healthy marine life you do not form coal, bitumen, petroleum, or similar products. Such products are vital for any long chain polymer based materials. So rayon, gortex, polyester, nylon, some metals, all sorts of super plastics, etc do not exist without 'oil' and it is only certain parts of oil that actually contain this material. Such materials are very difficult to synthesize (if not impossible) and are not available through stellar formative processes.

Such giant ships seem impractical to me, even given the pseudo-science that creates them. Even though these mighty vessels are essentially giant metal balloons, their mass would be incredible.

Currently for a modern rocket to leave orbit every ounce must be taken into account. Of course these ships are built in space but their mass would still be a factor during any kind of maneuver, and their inertia would work against them regardless of how powerful their thrusters could be. The lack of any medium (water or air) helps acceleration but it makes maneuver extremely slow and difficult. Building any speed requires constant acceleration and the simple act of turning requires deceleration, not just a touch of thrusters on one side. There's no way any of these vessels could ever maneuver to avoid incoming fire. We've been bombarded for too long with space imagery that can't possibly work in the real world; unfortunately real science takes a beating at times.

I'll start by saying i agree that the ships are inherently unrealistic.

BUT, defaulting to BFG rules, imperial/chaos ships had to move a significant chunk of their length just to do a 45 degree turn.

Of coarse, eldar had no such problems, but they "sail" (I guess furthering our nautical theme).

Changing tack, I actually think that the nautical theme goes beyond ship design; the entire concept of the warp and warp travel is similar to how ancient sailors viewed traveling the ocean.

There are too many similarities: travel over sea was much faster than land over great distances and let you access places no overland route could reach. But at the same time, there were unknown dangers and temptations, and the chance that you might arrive earlier or later (or never) than your intended destination time.

Can the Emperor build a ship so big that he can't lift it?

 Andrew1975 wrote:
Can the Emperor build a ship so big that he can't lift it?

Size really means nothing in space. And a bigger ship can have a bigger engine and as such can move and accelerate faster.

That's actually one reason why the idea of space fighters doesn't really hold up.


The weight of the ship also doesn't matter in zero-g. It won't collapse under its own mass/weight because it has no weight and mass will only effect momentum.

Like how a whale's massive body weight is supported by the water it lives in, so too will the lack of gravity support the ship.


All having a large mass will do is effect your ability to change speed and direction of movement, but then this is also countered by having more engine/thruster capacity.

It's energy large ships need more energy to accelerate, and gravity fields have more effect on a large ship than a small one.

Yes, but they also have more space to store and produce that energy.

also remember how GW operates things with.

always add a healthy dose of SPACE MAGICCC

Yes they are feasible.
Would they necessarily be the best thing to use?
It depends.
Troopships would definitely need to be massive.
Bombardment ships would also need to be pretty massive or consist mostly of just a gun and have minimal crew space and armour.