The first time someone explained the fourth dimension to me (referring to four dimentional euclidean space-not spacetime) they drew a picture of a tesseract and used the analogy of starships traveling through subspace at warp speed.

When ships are traveling at warp, are they traveling through euclidean space in the fourth dimension?

  • 1
    The way the navigational deflectors are described in the memory-alpha wiki makes it sound like Trek starships are still in our 3D space when traveling rather than some alternate dimension (like Star Wars Hyperspace seems to be), but maybe someone can find specific dialogue from one of the shows that clinches it.
    – Hypnosifl
    Nov 16, 2014 at 0:27
  • 2
    It all depends on how the engineers calculate warp speed really. The 4th dimension is time, so it will differ if the engineer that developed the warp drive did so using the theory that the universe is actually traveling through time and everything within is static, or the universe is static and everything within is traveling through time.
    – Robert
    Nov 16, 2014 at 0:30
  • 5
    @Robert - The fact that time can be treated as a dimension doesn't necessarily mean it is "the 4th dimension", that's just based on the assumption that there are 3 spatial dimensions, but many science fiction universes (along with real-life predictions of string-theory) suppose there could be additional spatial dimensions beyond the 3 we are normally confined to, and SF often uses the premise that one can travel faster than light by making a shortcut through such a higher dimension (science fiction authors took the name 'hyperspace' from mathematicians' term for higher space dimensions)
    – Hypnosifl
    Nov 16, 2014 at 0:34
  • 1
    I'm not sure what those huge pictures added to the question.
    – Valorum
    Nov 16, 2014 at 1:20
  • 1
    Time is the 4th dimension. You can treat subspace as fifth...
    – user931
    Nov 16, 2014 at 17:34

3 Answers 3



Within the Trek universe, ships travelling at warp speed are still capable of interacting with normal three-dimensional matter (with potentially disastrous consequences). This is why ships use a series of nested static shields known as navigational deflectors to move particulate matter out of the way, tractor beams to move medium-sized objects and sensors to detect and avoid larger objects that could prove a threat.

In TNG: Best of Both Worlds, Part II, Riker orders a collision course at warp, implying that this would have a more devastating effect than a collision at sublight speeds:

RIKER : Mister Crusher, ready a collision course with the Borg ship

Wesley reacts, turns and looks for confirmation...Repeating --

RIKER You heard me. A collision course.

WESLEY : Yessir.

RIKER : Mister La Forge, prepare to go to warp power...

and in Star Trek : The Motion Picture the crew have to take evasive action to avoid hitting an asteroid while travelling at warp:

DECKER : Negative control from inertial lag will continue 22 point five seconds before forward velocity slows to sub-light speed.

ILIA Unidentified small object has been pulled into the wormhole with us, Captain! Directly ahead...!

KIRK : Forcefields up full! Put object on viewer...!

The picture is switched through two further levels of magnification, enlarging the object: an elongated, distorted, pitted asteroid, tumbling toward the Enter- prise on a collision course.

CHEKOV (punching button) Torpedoes away...!


    as the starship's photon torpedo tubes EJECT GLOWING
    BALLS OF LIGHT ENERGY, which seems to float toward the
    oncoming asteroid, almost too slowly. And in these
    brief seconds, the asteroid hurtles at the Enterprise,
    the huge pitted rock growing even larger than the ship
    itself. It FILLS THE SCREEN, as the photon torpedoes
    hit, disintegrating the asteroid into thousands of
    fragments. Instantly, these fragments pulverize them-
    selves on the ship's forward forcefield and deflector
    screens. The smaller pieces burn up on impact, clearly
    outlining the ship's forcefield barriers.


    The asteroid fragments still smashing into the force
    field screen; the smaller bits like SPARKLERS as im-
    pact heat consumes them. The larger sections bouncing 
    away, the bridge QUIVERING as they hit.

    Then one final gigantic fragment strikes, the bridge
    SHUDDERS. And then the viewer shows only the normal
    SUB-WARP EFFECT: The stars ahead, relatively station-
    ary; a feeling of motion, but smooth, visually normal.

As regards the usefulness of the Navigational Deflector, n at least one episode of Voyager (Year of Hell, Part II) do we see the effects of it becoming inoperative (albeit in this case it's the objects that are moving at speed, not the ship)

KIM: Captain, with the deflector down those micrometeoroids are beginning to erode the hull.

JANEWAY: Emergency power to the deflector.

TUVOK: None available.

  • Voyager was not at warp during the micrometeoroid attack; indeed, just a few lines later, B'Elanna reports that "the warp core's still offline". Nov 17, 2014 at 12:23
  • @LightnessRacesinOrbit - It's not clear what speed they were traveling at, just that the core was offline. Note that you don't need the core to go to warp or stay at warp.
    – Valorum
    Nov 17, 2014 at 12:43
  • @Richard: It's pretty clear from the visual effects - wish I could find a screenshot. And yeah, aside from highly unusual circumstances, yes you do. That's what the warp core does. Nov 17, 2014 at 14:58
  • @LightnessRacesinOrbit - There's no visual of it actually happening.
    – Valorum
    Nov 17, 2014 at 15:33
  • @Richard: Yes there is; there's an establishing shot as the micrometeorites head into theatre. Voyager's just sitting there in space. You'd have to try very hard indeed to persuade me that, in the three seconds between the establishing shot and the first micrometeorite impact, Voyager had somehow jumped to warp (and not jumped past the entire field) without a functional warp drive, or an order from any of the senior staff, or any of the visual/audio effects that go with it. Nov 17, 2014 at 15:58

Within Star Trek on-screen canon, a vessel travelling at warp speed never leaves normal space, but manipulates "subspace fields" to warp normal space around it. There are examples of non-Federation space vehicles travelling "through" subspace as a mode of superluminal travel distinctly different from "warp drive", further supporting the notion that warp travel does not occur outside of normal space. The precise notion of what subspace is, and its role in warp travel is never really defined in on-screen canon.


For a somewhat...questionably canon answer:

In the second Star Trek TNG/XMen crossover novel (god help me) Geordi examines Nightcrawler in order to learn about how his teleportation abilities work. He eventually figures out:

  1. Nightcrawler access a different subspace than the one that the Enterprise does when it travels through Warp.

  2. Subspace is a separate universe from our own which has smaller dimensions even while otherwise corresponding to our own, which allows them to sort-of partially access Subspace, cruise along, and then pop back into regular space, having traveled a particular multiplier of the distance (the multiplier being the dimensional difference between the two universes). Note that when I say dimensional, I mean X,Y,Z dimensions.

As an aside, I always thought that this was a reasonable explanation for the warp speed cap. There are always claims about what a particular warp speed allows you to do, which is then broken and forgotten. To my mind, it may well be that the warp speed cap has to do with the maximum transversable speed in Subspace- perhaps the lightspeed limit in subspace is different.

  1. The Nightcrawler Subspace is in fact a tiny fraction of the size of Regular Subspace. Geordi estimates it to be something on the order of a few kilometers in size, which is why Nightcrawler can transition more or less any distance almost instantaneously. It's not that he's directly teleporting, it's that he only needs to move a fraction of an inch in his Subspace for it to correspond to almost whatever distance he likes in Regular Space.

  2. Nightcrawler Subspace mainly contains a lot of sulfur ions, some of which swap with his place when he accesses Subspace, leaving behind the characteristic brimstone smell. When he returns, some of it sticks to him, which brings the smell back again.

Geordi, as you may imagine, is very interested in studying the effect, with the idea of some day building a warp core around the particular effect and having ludicrously powerful starships.

  • EU is in no way, ever, in any condition, canon in Star Trek. It is Blessed Fanfic, and you quoted Blessed Crossover Fanfic.
    – Tritium21
    Nov 16, 2014 at 20:39
  • EU? I'm sorry, I'm afraid I'm not familiar with the term.
    – Broklynite
    Nov 16, 2014 at 21:01
  • Expanded Universe. Novels, comics, cartoons - nothing is canon in star trek other than filmed (or later, digitally captured) live action productions.
    – Tritium21
    Nov 16, 2014 at 21:01
  • Understood, thanks for the clarification. I still thought it was a pretty decent explanation for what Subspace is and how it works. I a series by (I think) Eric Flint which is more or less fighting sail in space, they laugh at the idea of "hyperspace" which increases the distance you have to travel because you add a dimension, while "subspace" reduces the number of dimensions, and therefore the distance decreases.
    – Broklynite
    Nov 16, 2014 at 21:05
  • That has no basis in star trek canon. Besides, the premise of this answer is faulty - Warp does not cause ships to enter subspace.
    – Tritium21
    Nov 16, 2014 at 21:07

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