OK, so I’m writing a Star-Wars-esque science fiction book set some centuries in the future. Rather than break the laws of physics and say that faster-than-light travel is possible, I’ve chosen to give ships wormhole engines— like warp drives or hyperdrives, except instead of speeding the ship up, it uses a dark energy generator to warp spacetime and open a wormhole for the ship to pass through to end up at a given destination.

My question: how, if it’s possible at all, would humans go about not only creating wormholes safely and regularly, but also creating them with specific entrances and exits, that is, they can control where the wormholes begin and end in space. For some reason or another, humans cannot cause the wormholes to end at any other time than the present.

So is it possible to fine tune the space part of a rift in space-time, and not the time part? If so, how large would the generator be? (I’m intent on the whole dark energy thing) Could it plausibly fit on a spaceship? How quickly would a person be able to whip up a wormhole on command? How dangerous would it be to travel through a new wormhole, and how long would it remain stable for after creation?

Sorry if I’m overloading on the questions, but this is the one part of my book that really needs some clarity in my head. I can’t allow time travel for obvious reasons, but I also can’t allow FTL, and wormholes seemed like the go-to solution.

Thanks in advance!

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    $\begingroup$ Define "present." That's THE fundamental problem of relativity -- there is no singular present. Any current event here happens in the past from some points and in the future from other points. Crossing space with FTL (and wormholes count as FTL) causes relativity problems. Your question is thus unanswerable unless you detail how you want to resolve that. $\endgroup$
    – SRM
    Commented Apr 16, 2017 at 14:32
  • $\begingroup$ OK. I define the present as whatever the current Universal Time (based in Utah, I believe) is recorded as at the time the wormhole is opened. Looking at that time before and after traveling through the wormhole shouldn’t cause any huge gaps, if you see what I mean. $\endgroup$ Commented Apr 16, 2017 at 14:56
  • $\begingroup$ @KaiChristensen Doesn't work like that. The "Current Universal Time" is different for everyone looking at the clock; eg: the present isn't consistent. $\endgroup$
    – Aify
    Commented Apr 16, 2017 at 16:47
  • $\begingroup$ @kai because velocity and gravity change spacetime, you can never meaningfully determine whether any two events occurred at the same time for any interstellar distance. At star X, they see your Utah clock strike noon and then they see star Y go nova. At star Z, they see star Y go nova and then see the Utah clock strike noon. Both are correct because time is relative. That's the frustrating result of Einstein's discoveries, confirmed in many more experiments since then. $\endgroup$
    – SRM
    Commented Apr 17, 2017 at 0:06

3 Answers 3


Wormhole Stability

Although the General Relativity equations permit wormholes to exist, they aren't stable long enough for any mass (even a photon) to traverse them. Ultimately they collapse trapping the object attempting to pass through.

At least this is true for all the matter we've discovered so far.

In order to make a worm hole "stable", it needs to be threaded with matter that possesses a property called "Negative Mass".

From the link:

In theoretical physics, negative mass is a hypothetical concept of matter whose mass is of opposite sign to the mass of normal matter, e.g. −2 kg. Such matter would violate one or more energy conditions and show some strange properties, stemming from the ambiguity as to whether attraction should refer to force or the oppositely oriented acceleration for negative mass.

Also from the link:

o Positive mass attracts both other positive masses and negative masses.

o Negative mass repels both other negative masses and positive masses.

For two positive masses, nothing changes and there is a gravitational pull on each other causing an attraction. Two negative masses would repel because of their negative inertial masses. For different signs however, there is a push that repels the positive mass from the negative mass, and a pull that attracts the negative mass towards the positive one at the same time. Hence Bondi pointed out that two objects of equal and opposite mass would produce a constant acceleration of the system towards the positive-mass object, an effect called "runaway motion" by Bonnor...

Wormhole handles

The matter with negative mass, which holds your wormhole open, also gives it anchor points. If you move the framework of this matter, you also must move the wormhole.

So if you want a plausible wormhole, you must also plan for it to have handles that humans can move around.

Time travel

Whether you like it or not, the introduction of FTL through space, also gives you time travel.

Kip Thorne's discussion of Time Travel and Wormholes:

Thorne takes his wormhole and puts one end in his living room, and the other aboard a spaceship parked in his front yard. Thorne's wife, Carolee, hops aboard the spaceship to prepare for a trip. The two don't have to say goodbye, though, because no matter how far away Coralee travels, they can see each other through the wormhole. They can even hold hands, as if through an open doorway.

Carolee starts up the spaceship, heads into space and travels for six hours at the speed of light. She then turns around and comes back home traveling at the same speed — a round trip of 12 hours. Thorne watches through the wormhole and sees this trip occur. He sees Coralee return from her trip, land on the front lawn, get out of the spaceship and head into the house.

But when Thorne looks out the window in his own world, his front lawn is empty. Coralee has not returned. Because she traveled at the speed of light, time slowed down for her: What was 12 hours for her was 10 years for Thorne back on Earth.

Now, as Thorne and Coralee hold hands through the wormhole, they are each traveling in time. Coralee has landed on Earth 10 years after she left, and there she will meet Thorne, 10 years older. But she can still reach through the wormhole and find Thorne, who is only 12 hours older. Thorne can step through the wormhole and find himself 10 years in the future, or his future self can step back 10 years into the past.

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    $\begingroup$ The time travel example makes my brain twitch and go "ow." But quite accurately portrayed. Now, what if the time flowed at different rates on either end of the wormhole? Would that work? e.g. it avoids the time travel issue because as Thorne looks through the wormhole he sees that everything his wife does is in slow motion (and probably redshifted like crazy). $\endgroup$ Commented Apr 16, 2017 at 15:55
  • $\begingroup$ @Draco18s that's equivalent to having the living room be on the spaceship. You've only moved the problem from the wormhole gate to the house's front door. :-( $\endgroup$
    – SRM
    Commented Apr 17, 2017 at 0:11

So, first, read my comment on your question. That helps define the problem you're trying to solve.

I think the only way to address it is like this: suppose any particle (muons, leptons, etc) creates some sort of field called the consistency field. As the particles move, that field gets folded in its own geometric space. The field cannot fold through itself and acts as a forcing function on all wormholes. Therefore, whenever a ship enters a wormhole, the endpoint will be the nearest point in time that doesn't contradict the light cone of the point of origin. In other words, if A and B are 2 light years apart, light from B at time Bt arrives at A at time At. if someone leaves A via wormhole, they will be entangled with the light that arrived from B, so they cannot arrive any earlier than Bt. Now they try to go home. But while they are at B, more light from B is traveling to A, and takes 2 years to get there, so the earliest the wormhole home can arrive is (At+2 years).

This means ships have to track their inventories VERY closely. A single stray particle from a far away system that already took a shortcut through a wormhole might stow away on a ship. That one particle stowaway on board can force the ship far into its own subjective future, with no hope of return.

The energy requirements are going to have to wait for someone else (and I recommend you put that in a separate question once you have an answer to how you want the wormholes to work).


My answer is going to adress two points: controlling wormholes, and feasability of them within our current understanding of physics.

Our understanding of the mathematics of the Field equation shows us that wormholes are a solution - but we have no evidence of them in the real world and we think if they do exist they cannot be stable for long periods of time (I reccomend you watch this video as it does a great job of explaining a lot of my answer), also they have to be subatomic - else you would need a couple of suns to power this portal. Furthermore, we do not have any idea at all how to control them (if they even exist)

Taking an example from the video: if you want a wormhole about the size of a door,y ou need to displace the equivalent mass of the moon every single second, so convert that to some E=mc^2 and you can start to see the problem, so get your handwavium generator sorted before discussing fine tuned portals, WE DO NOT KNOW if / how they can be controlled, so yuo kinda have to make up your own response here


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