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Of all the speculative science and handwavium surrounding the biology of Tyranids, the bio-ships confuse me the most. If any of you have answers to the following questions, I would like to hear them.

1. How do they move? With nothing to push off of, the only way I can think of that would allow the 'nids to move is to vent some gas, like methane. This, however seems like it would drain enormous amounts of biomass when the ships had to make rapid course corrections, say, in combat. How do they sustain this, or do they move using some way I cannot think of.

2. Cell respiration. How, over the countless millenia it takes a hive fleet to move between galaxies, do the cells of the organisms sustain the chemical processes needed to sustain life? Due to the extreme distance from any solar body, it seems impossible for them to be autotrophic, and even any nuclear-to-biological power source would decay in the vast space of time, or be too slowly decaying to power anything. They can't even draw power from the warp, for fek's sake, because they have no "true" psykers. And any "suspended animation" type deal would have to slow them down basically to the point of death and then resurrection to last that long. Of course, this all begs the question of how they know when to wake up.

That's all I can think of for now, but if any of you guys have some more, feel free to ask them too.

1. Narvhals. These bugs pull the fleet along with themselves as they hook into the gravity-well of a distant planet and somehow use it to create a space-time tunnel, through which the fleet passes.

2. Hibernation, and xeno-biology that is different from our own, and beyond our understanding.

It's 40k, anything can happen.

The issue is that 40k really is not speculative/science fiction but actually Science Fantasy mixed with Space Opera and Homeric Epic.

Things do not need to make sense...this is not the universe of Asimov, its more like Haldeman's "tachyon drive" its there, we know what it does, but no one knows how, nor will they ever.




Automatically Appended Next Post:
This is a universe where a 30m tall walker is considered a good idea. Where interstellar space travel is made possible by passing through the bizzaro universe. And were an entire race can dowload their "souls" into robot bodies, but very very poorly.

Anything goes in the 41st millenium

theonetruedonut wrote:Of all the speculative science and handwavium surrounding the biology of Tyranids, the bio-ships confuse me the most. If any of you have answers to the following questions, I would like to hear them.

1. How do they move? With nothing to push off of, the only way I can think of that would allow the 'nids to move is to vent some gas, like methane. This, however seems like it would drain enormous amounts of biomass when the ships had to make rapid course corrections, say, in combat. How do they sustain this, or do they move using some way I cannot think of.

2. Cell respiration. How, over the countless millenia it takes a hive fleet to move between galaxies, do the cells of the organisms sustain the chemical processes needed to sustain life? Due to the extreme distance from any solar body, it seems impossible for them to be autotrophic, and even any nuclear-to-biological power source would decay in the vast space of time, or be too slowly decaying to power anything. They can't even draw power from the warp, for fek's sake, because they have no "true" psykers. And any "suspended animation" type deal would have to slow them down basically to the point of death and then resurrection to last that long. Of course, this all begs the question of how they know when to wake up.

That's all I can think of for now, but if any of you guys have some more, feel free to ask them too.

1:"nothing to push off of" this is a popular misconception of space, there are many many things to "push off" one of the main ones is the mass of the object itself, so venting gas as you said would push the mass of the object in a direction, another one is graity itself, even at vast distances gravity has an effect, its an ever present force.
My idea if nids was that they use both solar winds and self propultion, they sort of "swim" through space

2: They enter a state of suspended animation, i agree this is handwavium.
And nids do use warp power in a psychic sense, its just not the same as say a librairian.

Heres one for you.... old one eye is unique, how did it get off macragge???

Formosa wrote:

Heres one for you.... old one eye is unique, how did it get off macragge???

Hitched a ride on the last feeder tentacle to get pulled up.

Psienesis wrote:1. Narvhals. These bugs pull the fleet along with themselves as they hook into the gravity-well of a distant planet and somehow use it to create a space-time tunnel, through which the fleet passes.

I get Narvhals, but once they make it into a solar system, how do they navigate? As I understood it, this was for inter and intra-solar system travel only, not for movement inside a gravity well or between galaxies.

Also, as for this:

Formosa wrote:Heres one for you.... old one eye is unique, how did it get off macragge???

This is explained in the codex; basically, One-Eye's experiences and biological make up are basically copyn'pasted through the hive mind and spat out by a Norn Queen somewhere else. Why the copy only has one eye, though, I don't know.

It's space, you don't need constant thrust, especially when heading into a gravity-well. The bug farts once, that's enough to push it towards a planet once in-system, gravity and physics do the rest.

Psienesis wrote:It's space, you don't need constant thrust, especially when heading into a gravity-well. The bug farts once, that's enough to push it towards a planet once in-system, gravity and physics do the rest.

Yeah you do. In combat actions, when positioning to deploy spores, moving to cover different parts of the planet, escaping the gravity when you are done, all these things require thrust and acceleration, which the only way I can think of achieving is venting precious biomass into the void.

You don't need it going into a gravity well (because the planet will draw you into it on its own) and we're talking about the approach of a Hive Fleet, we haven't said anything about it having to fend off anything yet (which only requires thrust for the ships moving out of the way, but they might be using gravity-sail-like-wings or something for combat speed, in the same vein as the Eldar do). Doesn't matter, because these fighter/bomber-bugs aren't around until they're needed, really. The fleet eats them. Saves on weight, provides biomass for the trip. They'll spawn some of these mindless swarms if threatened, not before.

Once in orbit, if the ship doesn't plan on entering the atmosphere, it only needs a bit of thrust now and then to keep it in the air and make any corrections to its altitude or facing, it doesn't need a constant thrust to maintain orbit. Same, again, on the approach to the world... once you're in sight of it, if you know which way it orbits, you can just point your way there, give yourself a push, and meet it when it swings round that way.

Escaping a planet's gravity well is slightly harder, but most of the Hive Ships aren't deeply in it, they're in a low orbit (still well above the limits of the atmosphere) fueling up at the capillary towers. Bugs on the ground don't come back up to orbit, not under their own power, anyway. They get eaten, too. Once the Hive Ships are done? They push off with another belch, and hook up with a Narvhal again, and are then pulled along by its gravity-tunnel thing.

Of course they use biomass doing this. This is why the Tyranid have never stopped somewhere (other than being stopped by some other agency) to just pig-out. They use up biomass just by existing, so they are always going to need more. Just as a human cannot eat a large meal and survive for the rest of his natural life, neither can the Tyranids content themselves with just one world.

Psienesis wrote:You don't need it going into a gravity well (because the planet will draw you into it on its own) and we're talking about the approach of a Hive Fleet, we haven't said anything about it having to fend off anything yet (which only requires thrust for the ships moving out of the way, but they might be using gravity-sail-like-wings or something for combat speed, in the same vein as the Eldar do). Doesn't matter, because these fighter/bomber-bugs aren't around until they're needed, really. The fleet eats them. Saves on weight, provides biomass for the trip. They'll spawn some of these mindless swarms if threatened, not before.

Once in orbit, if the ship doesn't plan on entering the atmosphere, it only needs a bit of thrust now and then to keep it in the air and make any corrections to its altitude or facing, it doesn't need a constant thrust to maintain orbit. Same, again, on the approach to the world... once you're in sight of it, if you know which way it orbits, you can just point your way there, give yourself a push, and meet it when it swings round that way.

Escaping a planet's gravity well is slightly harder, but most of the Hive Ships aren't deeply in it, they're in a low orbit (still well above the limits of the atmosphere) fueling up at the capillary towers. Bugs on the ground don't come back up to orbit, not under their own power, anyway. They get eaten, too. Once the Hive Ships are done? They push off with another belch, and hook up with a Narvhal again, and are then pulled along by its gravity-tunnel thing.

Of course they use biomass doing this. This is why the Tyranid have never stopped somewhere (other than being stopped by some other agency) to just pig-out. They use up biomass just by existing, so they are always going to need more. Just as a human cannot eat a large meal and survive for the rest of his natural life, neither can the Tyranids content themselves with just one world.

I agree with all of this, but just want to add that unfortunately for us, this is not an advantage due to the fact that only the most barest and useless of minerals are undigestible for tyranids. In case they need to restock on biomass, they can just stop by any asteroid, rock, unhabitable planet or even gas giant and suck out all the minerals they can find, including iron, sand, oil, and probably 90% of the table of elements. If they were to eat up present day earth, all you'd have left with is a barren piece of black rock 1/10 the size it used to be. Imagine how many instruments of war we can build with that. And this is without the animal or plant population on the planet. With us being digested, they can biuld bugs that use/are those weapons. One successful feeding of a planet, inhabited or not, is enough to rebuild a fleet to conquer a subsector. The infestation of an entire subsector is enough to build a fleet large enough to warrant an imperial crusade. And even then, the chances of purgation are slim, for every man, tank, or ship lost, the tyranids gain one more asset.

Nids have Biological plasma cannons. I would assume they have some sort of biological Plasma drive(which works by ejecting charged particles)

Grey Templar wrote:Nids have Biological plasma cannons. I would assume they have some sort of biological Plasma drive(which works by ejecting charged particles)

Oh, yeah! I totally forgot about those. That seems like that would be far more efficient than just venting stuff. You still use fuel, just much more slowly. This seems like it would work.

If one looks at the BFG background, from the online GW BFG Tyranid supplement, there is mention of "discharge vents" and also solar vanes for propulsion and turning. Remember that aside from the actual biomass of the living ecosystems of a planet, the Tyranids also strip away material such as the atmosphere, and these gases can be used in a variety of ways, from being used in metabolism to being used for propulsion (or both). Tyranids while biological killing machines, are still ultimately living organisms and thus there will always be an unavoidable amount of inefficiency due to thermodynamic considerations. There will be waste. While waste products might be reprocessed to squeeze more energy out of them, there will be a point where it becomes not worth the effort or energy to do so. Then such waste has to be disposed of. What better way than to use this as reaction mass for propulsion? In doing so, the waste can be removed while still serving a useful purpose.

As for the amount used in movement, that actually helps resolve the other issue that has plagued the Tyranid consumption problem. Namely, how to explain what they do with the vast quantities of material they consume, since they do not seem to have converted all of it into Tyranids and overwhelmed everyone else. The sheer numbers have been crunched by others in the past, and going by those, the Tyranids should have had more than enough to overwhelm everyone. If some of that material is used for metabolism, in maintaining life, and then expelled, then that at least goes some way to help address this issue.

The thing about reaction drives (EG farting out gas) is that its not just the quantity of gas that is being expelled that matters, its the velocity said gas is moving at, and we don't really know how their propulsion systmes work beyond 'its a kind of reaction drive' so saying anything about its efficiency or capability is hard to do.

I would note the fact they can fire their weaponry to effect across thousands or tens of thousands of kilometres argues that they must be able to propel said masses at least at some reasonable velocity, as does the fact that they are not dramatically outperformed engine wise by any of their opponents in space. If that werne't the case then even the Imperium could dance around them in space combat.

Solar vanes would not be a terribly effective option for propelling multimegaton starships at any great speed in or out of the system (at least not by photon pressure) unless they had some sort of mass lightening.

I wouldn't rule out 'draw power from the warp' simply because they don't have psykers in the way the Imperium does (although I am not sure I buy that - aren't Zoanthropes psychic?) - given their strong connections to the warp via the Hive Mind and some of their more outlandish abilities (EG rapid regeneration) I'd say they're tapping more than a purely chemical/biological power source.

Then again I vaguley recall mention in some earlier fluff (2nd edition or thereabouts, possibly a few of the older short stories from the anthologies) of Space-ship grade spore mines (or some other tyranid munition) being thermonuclear (and also ejecting shrapnel.. an interesting concept that..)

Lightcavalier wrote:The issue is that 40k really is not speculative/science fiction but actually Science Fantasy mixed with Space Opera and Homeric Epic.

Things do not need to make sense...this is not the universe of Asimov, its more like Haldeman's "tachyon drive" its there, we know what it does, but no one knows how, nor will they ever.

Automatically Appended Next Post:
This is a universe where a 30m tall walker is considered a good idea. Where interstellar space travel is made possible by passing through the bizzaro universe. And were an entire race can dowload their "souls" into robot bodies, but very very poorly.

Anything goes in the 41st millenium

This right here is the answer.

So 40K is a bugs bunny cartoon? Cool that means the IG officer can stop the rampaging Khornate Berserker by cutting a hole through the ground with a saw and watching the poor bugger fall through into infinity

Edit: Also power levels are determined by beards. This is probably why the Squats were eliminated, because of the massive imbalance in gaming this introduced.

Connor MacLeod wrote:The thing about reaction drives (EG farting out gas) is that its not just the quantity of gas that is being expelled that matters, its the velocity said gas is moving at, and we don't really know how their propulsion systmes work beyond 'its a kind of reaction drive' so saying anything about its efficiency or capability is hard to do.

I would note the fact they can fire their weaponry to effect across thousands or tens of thousands of kilometres argues that they must be able to propel said masses at least at some reasonable velocity, as does the fact that they are not dramatically outperformed engine wise by any of their opponents in space. If that werne't the case then even the Imperium could dance around them in space combat.

Momentum is a function of both velocity and mass. We know the Imperium's ships move in realspace through throwing out plasma at high velocities out the rear of the ship. A Tyranid ship could achieve similar accelerations with greater mass and lower velocities ejected. If you look at the BFG background, Tyranid ships ARE at a disadvantage compared to even the Imperium in terms of general combat speed. They are also at a disadvantage in terms of weapon ranges, with only the larger hive ships having weapon ranges comparable to "moderate" Imperial weapon ranges (~45cm).

Tyranid weapons are also for the most part munition based consisting of organic shells or spikes with corrosive, toxic, or biological payloads, as per the BFG Armada supplement and BL novels such as Warriors of Ultramar. They are classed as "weapon batteries" under BFG rules, meaning they rely more on multiple salvos and area of effect than precision targeting. Thus there will be also mass and energy being expended in such weaponry.

Incidentally the scale given by Andy Chambers, who designed BFG, was 1cm= 1,000 km and the time scale a telescoping one with 1 turn = 1 hour at long ranges (like 60cm) and 1 turn = 15 minutes at short ranges (like 15cm).
( http://www.wolfedengames.com/battlefleetgothic/scale.htm )

Solar vanes would not be a terribly effective option for propelling multimegaton starships at any great speed in or out of the system (at least not by photon pressure) unless they had some sort of mass lightening.

It was never said these vanes move the ships by light pressure. That seems to be a conclusion you have jumped to. The relevant section says:

The ship has bio-engineered solar vanes that spread to absorb the smallest amount of ambient energy from surrounding space.

p. 92, BFG Armada
http://www.games-workshop.com/MEDIA_CustomProductCatalog/m2350032a_BFG_Necron_and_Tyranid_Fleets.pdf

Rather it seems to suggest these vanes are gathering energy. One could hypothesize how they would do so, whether it be something like photosynthesis or something more exotic. But ultimately, energy gathered could be used to drive things like more forceful ejection of reaction mass, which would still translate to the in-game effect of increased combat speed.

I wouldn't rule out 'draw power from the warp' simply because they don't have psykers in the way the Imperium does (although I am not sure I buy that - aren't Zoanthropes psychic?) - given their strong connections to the warp via the Hive Mind and some of their more outlandish abilities (EG rapid regeneration) I'd say they're tapping more than a purely chemical/biological power source.

Constantly using the handwavium of the warp kind of goes against the theme of Tyranids which is really as Andy Chambers put it "evolution gone mad". In other words, Tyranids are a nightmare born of realspace. Even though there might be warp power usage, it isn't the be all and end all of everything the way it is with factions like Chaos Daemons.

The whole confusion about whether Tyranids use warp power is a result of the change for change's sake Cruddace Codex. Even then it is inconsistent, at times portraying the Zoanthropes as channeling power from the Hive Mind and at other times not. However one workaround is that the Zoanthropes may be channeling warp energy that has been handed down and filtered through the Hive Mind, rather than the individual Zoanthrope channeling energy from the warp directly by itself. An analogy might be how the cells in a multi-cellular organism do not go around digesting their own nutrition from the environment but have nutrients and oxygen delivered to them via the other mechanisms of the organism. Such a filtered method of drawing upon the warp could for example explain how Tyranids don't seem to suffer from individual daemonic possession.

Connor MacLeod wrote: I wouldn't rule out 'draw power from the warp' simply because they don't have psykers in the way the Imperium does (although I am not sure I buy that - aren't Zoanthropes psychic?)

That'd be a no. Zoeys' enourmous noggins are used to channel and project the combined psychic presence of the hive mind into the powers that are used in game. Same thing with the powers you can get on Hive Tyrants.

Iracundus wrote: The whole confusion about whether Tyranids use warp power is a result of the change for change's sake Cruddace Codex. Even then it is inconsistent, at times portraying the Zoanthropes as channeling power from the Hive Mind and at other times not. However one workaround is that the Zoanthropes may be channeling warp energy that has been handed down and filtered through the Hive Mind, rather than the individual Zoanthrope channeling energy from the warp directly by itself. An analogy might be how the cells in a multi-cellular organism do not go around digesting their own nutrition from the environment but have nutrients and oxygen delivered to them via the other mechanisms of the organism. Such a filtered method of drawing upon the warp could for example explain how Tyranids don't seem to suffer from individual daemonic possession.

That is also interesting, I'd never though about it like that. However, I'd always thought it was more similar to the way an Ork Weirdboy channels the gestalt Waaagh! energy of the orks around him than a Human or Chaos psyker, with the Zoanthrope using the 'nids in it's immediate area to give it the psychic juice it needs to pop open a Leman Russ. On posession, I thought that stemmed more from the fact that the 'nids, being without emotion, had no individual warp presence to speak of, in addition to the dampening field put out through the Shadow in the Warp.

It was confirmed somewhere they use gas bladders when not drifting through space or using a narvhal.