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I'm still working on the background of a Sci-Fi setting, thinking about FTL travel. Wormholes seemed like a good idea, but I can't figure out all the implications of actually creating negative mass (to sustain the wormhole entrance) and using wormhole-based FTL travel, and I don't want to spread Misapplied Phlebotinum everywhere.

Basically the ship generates a shortcut between two points of the universe with a short-lived wormhole. Time travel isn't possible as the entry and exit points are stationary and don't move with the ship.

FTL ramming isn't possible either, because the ship never go faster than light (or faster than its cruising speed for that matters) at any given time. Sending warheads is of course possible.

FTL travel is kinda slow in-universe, taking several months to reach Proxima Centauri.

Opening wormholes inside stars, planets or other ships would be possible (as there isn't any magical sensors to detect the presence of gravity wells on the other side), but I don't know how it would look like. The ship would probably just merge with whatever it collides.


So, if someone has enough spare time to help me on this, it would be greatly appreciated.

Why bother with a spaceship? Why not simply go down the route of building ground installations a la Stargate? (or trains, for that matter )

What sort of size can these wormholes be, and how long can they be maintained? A small enough, long-lived-enough wormhole could be used either as I mentioned above or for use in mining. You could use one to bring daylight to the night side of a planet, for example.

Also, if they don't move with the ship, what are they stationary with respect to? The nearest massive object (a planet, a star)? If so, you'll need a minimum mass threshold otherwise they will move with the ship (apart from the ship traversing the wormhole itself).

That's only first-order technological effects. I'm sure there's all sorts of political and cultural issues that could come up. For example, if they're easy to generate, then you'll get all sorts of small groups setting up their own colonies*. On the other hand, now you don't need to crash planes into skyscrapers or leave car bombs in basements - just open up a wormhole between your target and space, and watch as they get sucked through (or link it to the centre of the sun). That'll get you a much greater level of governmental censorship and oversight of scientific knowledge and resources.

On the other hand, if it's fantastically expensive, then the majority of the population isn't going to see a benefit, unless they get shipped out as indentured workers in an asteroid mine.

* all of which presupposes there's somewhere to go to. Otherwise it'll end up as an interesting toy, and provide careers for that generation's Einsteins, Hawkings and the like, as we'll need some new grand physical theories.

In the setting, it's a somewhat new technology, in the hands of one big company which have monopoly upon space travel, space mining operations and space freighting. Humanity has only 5 colonies, no more than 1 million people per colony (at the moment). Sentient aliens are nowhere to be found, however complex extraterrestrial life exists (and was even discovered in the Solar System, on Europa).

Spaceships are rather big, the largest being 1.6km long cargo ships. Military ships are much smaller and maneuverable.

Wormhole mouths will probably move according to the nearest gravitational perturbation, but they're only created when the ship needs to get inside/outside and the ship itself cannot modify their location at will (it's always a one-way trip between two fixed sets of coordinates).

-> Thus unmanned FTL probes must to be sent to allow communications between colonies or ships.

The Human Ecumene's military has access to FTL travel, but it is really expensive and there isn't many spaceships anyway (the company has only a handful of cargo ships, and the military doesn't have much more).

Insurgent and terrorist groups were crushed decades ago. Colonies will probably try to gain their independence in the future, but they are way too young.

Violation of causality is the major implication of any FTL communication.

That said, as I understand it, Science has not made its mind up whether causality really exists or is merely an artifact of human psychology.

 Kilkrazy wrote:
Violation of causality is the major implication of any FTL communication.

That said, as I understand it, Science has not made its mind up whether causality really exists or is merely an artifact of human psychology.

Well, isn't it only true for real FTL speeds ? The whole point of wormholes is that information never exceed light speed. Sure you could, with a technobabble-powered telescope, see yourself entering the wormhole light-years away. But you can't communicate with your former self, as it's just an optical illusion, so everything is fine.

 LethalShade wrote:
I can't figure out all the implications of actually creating negative mass (to sustain the wormhole entrance) and using wormhole-based FTL travel, and I don't want to spread Misapplied Phlebotinum everywhere..

As someone who already wrote the first book in a series that deals extensively with this, all I can do is point you in the right direction.

First things first, if you don't have the following website as something to read, do it: http://www.projectrho.com/public_html/rocket/

Also, a great website to ask questions and get real answers: http://stackexchange.com/

The first website sets out what you have to do to solve your issues.

Opening wormholes inside stars, planets or other ships would be possible

What? You realize the levels of nonsense involved in that? Just the gravitational differences of a planet alone would cause havoc on the ship as it exited the wormhole.

You're probably looking at the "Portal" method, which is similar to wormholes except they reduce the distance between to points to 0, wormholes only shrink it down to close to 0.

Spaceships are rather big, the largest being 1.6km long cargo ships. Military ships are much smaller and maneuverable.

So cargo ships could completely out gun military ships with ease then?

Wormhole mouths will probably move according to the nearest gravitational perturbation

You have to realize that if you open a wormhole, it needs to stay put. What you're forgetting is in terms of the whole universe, everything moving really fast. Lets ignore the fact that galaxies are flying around and ludicrous speeds, or that galaxies are spinning/stuff inside them is moving, or that the speed of a planet is actually pretty damn fast when it's in orbit. Everything moving, you need to account for this, not simply say "it just works"

Insurgent and terrorist groups were crushed decades ago

Completely? Nonsense, space is big, lots of room for dissidents. Furthermore you will always have those with differing opinions.

in the hands of one big company which have monopoly upon space travel

Which means people are actively trying to steal the knowledge.


I'll do my best to monitor this thread and help answer questions.

 LethalShade wrote:

Spaceships are rather big, the largest being 1.6km long cargo ships. Military ships are much smaller and maneuverable.

Just to seize on this, this will not be the case in reality due to how movement in zero gravity works. Because you are only dealing with the constraints of inertia its actually larger ships with bigger engines that will be the fastest. They will have more mass, and thus take more energy to change direction, but because they are larger they can have larger engines which totally outstrips the issue. The smaller the ship, the more of its mass must be taken up by engines to allow it to maintain a certain speed. It will also be able to mount far more weaponry. Smaller only equals more maneuverable when we have an atmosphere to deal with. Plus in space there isn't really much to hide behind, so really any fight will boil down to who has the most guns and best armor.

Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

 Grey Templar wrote:


Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

Wait, are you saying 40K got space combat right?

 juraigamer wrote:

 LethalShade wrote:
I can't figure out all the implications of actually creating negative mass (to sustain the wormhole entrance) and using wormhole-based FTL travel, and I don't want to spread Misapplied Phlebotinum everywhere..

As someone who already wrote the first book in a series that deals extensively with this, all I can do is point you in the right direction.

First things first, if you don't have the following website as something to read, do it: http://www.projectrho.com/public_html/rocket/

Also, a great website to ask questions and get real answers: http://stackexchange.com/

The first website sets out what you have to do to solve your issues.

Opening wormholes inside stars, planets or other ships would be possible

What? You realize the levels of nonsense involved in that? Just the gravitational differences of a planet alone would cause havoc on the ship as it exited the wormhole.

You're probably looking at the "Portal" method, which is similar to wormholes except they reduce the distance between to points to 0, wormholes only shrink it down to close to 0.

Spaceships are rather big, the largest being 1.6km long cargo ships. Military ships are much smaller and maneuverable.

So cargo ships could completely out gun military ships with ease then?

Wormhole mouths will probably move according to the nearest gravitational perturbation

You have to realize that if you open a wormhole, it needs to stay put. What you're forgetting is in terms of the whole universe, everything moving really fast. Lets ignore the fact that galaxies are flying around and ludicrous speeds, or that galaxies are spinning/stuff inside them is moving, or that the speed of a planet is actually pretty damn fast when it's in orbit. Everything moving, you need to account for this, not simply say "it just works"

Insurgent and terrorist groups were crushed decades ago

Completely? Nonsense, space is big, lots of room for dissidents. Furthermore you will always have those with differing opinions.

in the hands of one big company which have monopoly upon space travel

Which means people are actively trying to steal the knowledge.


I'll do my best to monitor this thread and help answer questions.

Thanks for the reply.

First point : Yep, the ship would be utterly destroyed.

Cargo ships would indeed out gun military if they had weapons.

Concerning wormhole moving, that's exactly what I wanted to say. The spelling was quite random, I admit.

Completely crushed ? Nope. But that's kinda obvious. Just wanted to say that no insurgent cell is currently actively opposing the government. If they're up to something, they're still trying to figure out what to do and how.
Legal opposition (politicians and so on) is of course active.

Even with the knowledge, you need the infrastructures to produce the drive and the ship (or just steal both of them). And it would take a lot of time. (Definitely possible though)


Grey Templar -> Yep... That seems right. It all depends on the power source anyway.

Just have the ships rip into an alternate dimension filled with sentient beings that we don't understand.... Then, you have these ships protected by "special" people who have "abilities" to keep those sentient beings from getting inside your ship.


What could possibly go wrong?

 Ensis Ferrae wrote:
Just have the ships rip into an alternate dimension filled with sentient beings that we don't understand.... Then, you have these ships protected by "special" people who have "abilities" to keep those sentient beings from getting inside your ship.


What could possibly go wrong?

Absolutely nothing *gets slaughtered by a random Lord of Change*

squidhills wrote:

 Grey Templar wrote:


Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

Wait, are you saying 40K got space combat right?

Oddly enough yes. Aside from space fighters, but every sci-fi needs space fighters.

Well, wouldn't realistic space battles be two fleet engaging each other thousands of kilometers away (or just filling space with warheads/mines/drones eating the hull) ?

That's what they do in 40k. Ships are engaging at tens of thousands of kilometers apart. Many planets are defended with asteroid belt sized minefields.

 Grey Templar wrote:
Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

Depends. Some ships could be armed with massive loads of missiles; pods of decoy, control and active warheads fired in sequential ripples.

Depending on drive and inertia dissipating technology (to save the soft squishy crew) you may also see smaller ships and carriers.

 LethalShade wrote:
Well, wouldn't realistic space battles be two fleet engaging each other thousands of kilometers away (or just filling space with warheads/mines/drones eating the hull) ?

Yes and no. If you ship defenses are not very strong, IE you don't have shields and armor isn't up to snuff then yes you would be a super long ranges shooting each other.

However, ranges in space coupled with movement means you'll still be kinda close. There's also the light speed delay when firing weapons. Many people assume it will be massive of missiles that may or may not have explosive charges.

Now if countermeasures are pretty strong and shields are common, then ranges would be closer. The main reason is if you have shields, you have particle weapons which are exceedingly strong energy weapons. Particle weapons however are short range, so ships need to get reasonably close.

It's also important to note that maneuverability is directly related to mass. The largest ships take forever to turn, but smaller ships can preform crazy moves. Problem is, you can only go so fast before the g-forces become a massive issue.

Please take the time to read the atomic rockets page, I spent a good month acting like an amateur scientist with all the info I had to compile for my setting.

 juraigamer wrote:

Please take the time to read the atomic rockets page, I spent a good month acting like an amateur scientist with all the info I had to compile for my setting.

I'm already reading it

 SilverMK2 wrote:

 Grey Templar wrote:
Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

Depends. Some ships could be armed with massive loads of missiles; pods of decoy, control and active warheads fired in sequential ripples.

Depending on drive and inertia dissipating technology (to save the soft squishy crew) you may also see smaller ships and carriers.

Those aren't necessarily mutually exclusive concepts. We could easily have battleships firing wave after wave of missiles at each other in addition to projectile weaponry. With laser defenses missiles would only become viable if launched in huge numbers to overwhelm them. So cheaper would be better, only rudimentary guidance systems.

 Grey Templar wrote:
With laser defenses missiles would only become viable if launched in huge numbers to overwhelm them. .

That doesn't really matter, since at high speeds even shrapnel will disable said missiles in space. Point defense flechette missiles to intercept other missiles. The missile vs missile battle isn't useful. Considering that much metal was used, you're better off just making more ships.

It's actually far better to have incredibly high yield torpedoes with at least fore mounted shielding that are launched close to your target. Use drones to protect it as it flies at ever increasing speeds towards its target.

Now mass drivers of some sort would work as well, after all the explosions in space don't help much unless you can explode inside the enemy craft. Problem is that's more mass the ship has to fly around with, so you end up with this weird catch-22 situation.

 Grey Templar wrote:

 SilverMK2 wrote:

 Grey Templar wrote:
Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

Depends. Some ships could be armed with massive loads of missiles; pods of decoy, control and active warheads fired in sequential ripples.

Depending on drive and inertia dissipating technology (to save the soft squishy crew) you may also see smaller ships and carriers.

Those aren't necessarily mutually exclusive concepts. We could easily have battleships firing wave after wave of missiles at each other in addition to projectile weaponry. With laser defenses missiles would only become viable if launched in huge numbers to overwhelm them. So cheaper would be better, only rudimentary guidance systems.

Or more expensive, more able stealthing and EW missiles

Laser defences are only good if you can see the targets and can hit them with any accuracy, while flak defenses are only good if you can saturate a volume of space with enough material (which could be good for knife fight ranges or static installations but not much good for mobile warfare).

Missiles also are able to attack from outside the obvious threat zone and using bomb pumped lasers you can have significant stand off range amd power.

 Grey Templar wrote:
Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

No, they really won't. Not at all. Armor means mass, and mass means your fuel requirements very quickly end up in the wrong part of the exponential curve. Much like modern aircraft any realistic warship is going to have an absolute minimum of armor (a very thin layer to avoid having a hole punched in the hull because you hit a grain of sand at high relative velocity) and durability will consist of redundant backup systems. And even that is going to be severely limited by mass issues.

A realistic space warship is going to be a giant fuel tank with tiny crew and weapon systems bolted on. And there will not be any thunderous broadsides. Combat is going to happen one of three ways, depending on the relative merits of laser and missile technology:

1) An exchange of missile salvos that take months (or even years!) to reach their targets, followed by an extremely brief match of point defense lasers vs. missiles that decides who lives and who dies. This quite possibly ends in mutual annihilation.

2) An exchange of laser shots at extreme range that probably kills both sides unless one side has a significant advantage in focusing and aiming technology. Even the "winner" is likely to suffer damage before they can shut down the enemy's lasers, and a damaged ship is probably a dead ship even if it survives the battle itself.

3) Why are we even fighting? There's no stealth in space, both sides probably know what the outcome of the battle is going to be, so why even take the battleships out of their parking orbits? Conflicts are decided by political alliances and nobody ever bothers with the formality of a shooting war.

 Peregrine wrote:

 Grey Templar wrote:
Realistic space warships will more closely resemble 18th century warships, massive vessels bristling with guns and armor that engage in thunderous broadsides.

No, they really won't. Not at all. Armor means mass, and mass means your fuel requirements very quickly end up in the wrong part of the exponential curve. Much like modern aircraft any realistic warship is going to have an absolute minimum of armor (a very thin layer to avoid having a hole punched in the hull because you hit a grain of sand at high relative velocity) and durability will consist of redundant backup systems. And even that is going to be severely limited by mass issues.

A realistic space warship is going to be a giant fuel tank with tiny crew and weapon systems bolted on. And there will not be any thunderous broadsides. Combat is going to happen one of three ways, depending on the relative merits of laser and missile technology:

1) An exchange of missile salvos that take months (or even years!) to reach their targets, followed by an extremely brief match of point defense lasers vs. missiles that decides who lives and who dies. This quite possibly ends in mutual annihilation.

2) An exchange of laser shots at extreme range that probably kills both sides unless one side has a significant advantage in focusing and aiming technology. Even the "winner" is likely to suffer damage before they can shut down the enemy's lasers, and a damaged ship is probably a dead ship even if it survives the battle itself.

3) Why are we even fighting? There's no stealth in space, both sides probably know what the outcome of the battle is going to be, so why even take the battleships out of their parking orbits? Conflicts are decided by political alliances and nobody ever bothers with the formality of a shooting war.

If you have FTL, just send a nuclear warhead on the planet/fleet.

Realistically, yep. Starships are fuel tanks. But it's kind of boring, to be honest.

 LethalShade wrote:
If you have FTL, just send a nuclear warhead on the planet/fleet.

Well, nukes aren't actually that powerful. There's no blast effect in space so you either need a direct hit (or at least "direct" by the standards of space combat) to kill a ship with the heat or a proximity shot to kill a ship with radiation. Either way you're only hitting one target at a time because ships in space have no need to be anywhere near each other. So the "drop a nuke in the middle of the fleet" strategy is just wasting your nukes. On the other hand, missiles will almost certainly be armed with nuclear warheads (with or without bomb-pumped lasers) since a proximity kill from radiation is still way more than you could possibly hope for with anything short of a nuclear warhead.

The real issue with "if you have FTL" is that most ways of adding FTL to a setting tend to do really bad things to the maximum possible kinetic energy of a ship. There's not much point in using nukes against a planet when a small cargo shuttle crashing into the planet at a high fraction of the speed of light makes the asteroid that killed the dinosaurs look like a pretty fireworks display.

Realistically, yep. Starships are fuel tanks. But it's kind of boring, to be honest.

Depends on the story and what you expect to get out of it. Realistic starships don't have to be boring just because they don't look like Star Wars battles, they're just interesting for different reasons.

That kind of assumes reaction rockets are still the primary means of getting around.

There are various energy drives in early stages even today which may become powerful enough to move large ships. Many of these use little to no fuel (I saw one in the news this week which uses 100 times less fuel than a conventional rocket to do the same trip).

Armour also would depend on what exactly you are shielding against; laser weapon shielding may well be highly heat conducting wires embedded in the hull to dissipate heat and linked with radiator fins. Particulate weapon shielding may well be laminate layers of composites which fail in a controlled way to dissipate kinetic energy (and which while heavier than no armour are still reasonably light). You may even get charged fields which deflect beams and projectiles before they reach the ship.

Stealth materials, drive shields and so on will all make a ship more difficult to spot. Active EW will make a shio harder to spot and hit.

There is such a wide variation in possible tech levels that any number of outcomes is possible. It is far better to decide what kind of space warfare you want and build the tech level to suit it.

Even at low level tech, one side having a perceived or real technological, positional or other advantage could still lead to war.

Little to no fuel ? With a reactionless drive maybe. I guess a significant part of the ship needs to be fuel even with a fusion power source.

How does a corporation have a monopoly on this wormhole drive? Is it a utopian society (you mentioned lack of insurgents) and everyone is content (goverments and individuals) to have one company have the secret tech needed to travel the galaxy? The most powerful nation on the planet can't keep the president's indiscretions a secret (billy c), but one company managed to design test and manufacture ftl drives without anyone being able to compete?

 LethalShade wrote:
Little to no fuel ? With a reactionless drive maybe. I guess a significant part of the ship needs to be fuel even with a fusion power source.

Again, really depends on the drive tech. Bunkerage of reaction mass/reactor mass would certainly take up some volume and mass, but you really need to define the drives before saying how much.

Either way, compared to a rocket drive, it would be pretty much nil

I remember a professor in college going through some equations for a theoretical wormhole. The math itself was beyond me, but the conclusions were interesting. In general not only are they monstrously unstable and likely very short lived, usually a fraction of a second, and you'd need one thousands of miles across to allow passage of anything like a ship through intact, as tidal forces are incredibly powerful. A two mile wide wormhole that ostensibly looks like you could throw anything in it would tear apart just about anything larger than a walnut.

 Torga_DW wrote:
How does a corporation have a monopoly on this wormhole drive? Is it a utopian society (you mentioned lack of insurgents) and everyone is content (goverments and individuals) to have one company have the secret tech needed to travel the galaxy? The most powerful nation on the planet can't keep the president's indiscretions a secret (billy c), but one company managed to design test and manufacture ftl drives without anyone being able to compete?

Utopian society ? Hahahahaha.
No.

There is one "unified" authoritarian government for the whole Human Ecumene (Solar System + Five colonies, almost 18 billion humans), firmly interlaced with Lux Conglomerate (the corporation).
Not a particularly cruel one, but not kind either. Insurgents are into hiding.

Basically, Lux Conglomerate controls the whole production chain, from mining to manufacturing and they are the only ones to produce FTL drives (They discovered it after all), space elevators, mining probes and spaceships (but they're not the only ones to use them).


Vaktathi -> It needs to be stabilized with some kind of exotic particle with negative mass, IIRC.

SilverMK2 -> True

Fixed jump point or gate based science fiction has its merits. As you have routes between jump points that do not deviate. This means you can have de facto terrirtorial expansion in space, and deffacto fortification in space. Wormholes beome choke points and orbiting fortress space stations guard them, either that or fleets.
You can have unstable wormholes only smaller smuggler ships can traverse to open things out, you can have newly discovered wormholes that change the map and direction of travel. You can have transport routes system to system that pirates can picket. You can have devices that close wormholes for good.
Most of all you can have a starmap that makes sense in real terms mad up of systems with linked lines between them. Its unambiguous and not scale dependent, you can avoid movement scale in sapce altigether with this system, but you can also do so with jump and hyperdrive travel.

You can add a lot of room for politics and map based strategy to your SF with this type of system. Warp or hyperdrive movement allows far more freedom but when you consider the vastness of space it means that combat is only realistic near planetary orbits.