What is the flash of light produced when the Enterprise-D goes into warp? I guess it's the ship entering subspace, but I'm not sure. Also, why don't Ferengi, Romulan, and other non-Federation ships produce this light?

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    For the life of me, I can't remember any instances when we've seen another faction's ship(s) go into warp.
    – Xantec
    Commented Aug 14, 2014 at 2:13
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    In TNG's "The Last Outpost" we see a Ferengi ship jump to warp as they retreat. No flash of light.
    – Kyle Jones
    Commented Aug 14, 2014 at 2:46
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    No idea with the Ferengi, but the Romulans do use a different method of propulsion: their ships are powered by an artificial quantum singularity (en.memory-alpha.org/wiki/…) - and mostly cloak themselves before going to warp. If they produced a flash of light that would kind of negate the cloaking.
    – BMWurm
    Commented Aug 14, 2014 at 7:03
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    I distinctly remember an episode of DS9 where the Defiant, while in the Gamma Quadrant, has to drop out of warp, cloak and go silent in an effort to stop two Dominion warships discovering it - after a brief but tense scene in which the Dominion warships conduct a brief "did we see something or didnt we?" search, they go back to warp and in doing so you see them from the PoV of the Defiant and they do definitely produce the warp flash.
    – Moo
    Commented Aug 14, 2014 at 10:18
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    I've noticed, that it takes different amounts of time from engine-start to flare-appears: It's very fast with Voyager and takes a long time with the NX-01. Maybe the Romulans take longer to enter subspace and the camera just don't stay that long enough with the accelerating Warbird to capture the flash.
    – Einer
    Commented Aug 14, 2014 at 11:37

8 Answers 8


Although it's not explicitly stated elsewhere, the flash of light you see when a ship enters warp appears to be something called a "polyluminous burst".

In the Voyager episode Night, Tuvok used a photon torpedo's warp engine to deliberately create (and maximise) this flash:

TUVOK: ...Do we have the power to launch a photon torpedo?

KIM: Maybe one, why?

TUVOK: Perhaps we could shed some light on our predicament. I'm reconfiguring the torpedo to emit a sustained polyluminous burst.

KIM: A warp flare.

TUVOK: Precisely.

Since photon torpedoes are known to have Warp Sustainer engines (basically little tiny warp engines), it seems likely that this is how Tuvok is able to reconfigure it so easily from his command console. He simply ordered it to go to warp but in a way that maximised the 'flash', obviously at the cost of the torpedo itself.

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Further investigation would suggest that pretty much all alien ships also emit the same flash (albeit with their characteristic colouration) as shown in this footage from TNG and Voyager.

Out of universe, the reason is slightly more disappointing. The flash covers the transition from a static model (which could be filmed simply moving a camera away from the model) to a dynamic effects-based model

"One of the reasons that flash occurs in the opening credits when the ship goes into warp is because we switched from the six-foot model to the two-foot model. We used the two-foot model for the stretch effect, and the six-foot model for the fly-by. Well, they didn't quite match, so that's why the flash is there – to cover the fact that when we're switching from one model to the other, we kind of used it to cover the discrepancies between the two models." (Star Trek Generations (novel) (hardback), pp. 271-272)

There's an extensive discussion of the effect itself here.

  • I never interpreted this scene as photons magically jumping into warp on their own, and this light burst was sustained. I have no way to prove that your theory is incorrect, though. Commented Aug 14, 2014 at 10:47
  • @LightnessRacesinOrbit - Certain kinds of photon missiles are known to be warp-capable. All kinds are known to be warp-sustainer capable. Either way, they use the warp engine to make the flash, then use technical jiggery-pokery to make it last longer.
    – Valorum
    Commented Aug 14, 2014 at 10:50
  • There have been some alien-tech missiles have have been warp-capable and not just sustainable, but I don't recall any Federation missiles as having that ability.
    – Xantec
    Commented Aug 14, 2014 at 11:37
  • @Xantec: The missiles in the possession of the Marquis can do that - and that's Federation-tech if I'm not mistaken (enhanced with a Klingon cloak.)
    – Einer
    Commented Aug 14, 2014 at 11:39
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    Hmm, the clip got me thinking: what is the SOUND produced by the warp engines (in pure vacuum:)
    – Ajasja
    Commented Aug 14, 2014 at 20:21

Voyager does it, the Enterprise-E does it, the Defiant does it, the NX-01 does it, the Borg Transport from Enterprise does it, Jem'Hadar fighters do it... they all do it. There's no in-universe distinction.

It's just excessively prominent in the TNG opening credits due to differences in rendering the special effects.

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    Event educated fleas do it. Commented Aug 14, 2014 at 18:08
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    Obviously, you do it too...
    – PlasmaHH
    Commented Aug 14, 2014 at 19:01

Spock's World at one point indicates that all starships generate a flash of light on both entry and exit from warp. This light is said specifically to be Čerenkov radiation, i.e. the electromagnetic analogue of a sonic boom. However, the book implies that starships don't generate Čerenkov radiation continuously during FTL travel, because they are in an "otherspace" (the word "subspace" was not used) for most of the journey; it is only the transition to or from warp that "drags superrelativistic particles" (presumably some sort of tachyon) into normal space, and it's those particles that emit Čerenkov radiation.

Quotes (pp. 81–83 of this edition):

No one paid much attention to the view out the windows while a ship was in warp. The otherspace in which Enterprise traveled at such times ...

... So they saw what not too many people have an opportunity to see—a starship decelerating hard from warp, the point of a silver spear piercing through from the far side of the darkness in a trailing storm-cone of rainbows, as Coromandel came out of warp in a splendor of Cherenkov radiation from the superrelativistic particles she dragged into real-space with her...

... Coromandel accelerated away on impulse, then flung a cloak of spectrum-colored fire about herself, leaped away, and was gone from sight on the instant.

Caveat 1: The book only shows this happening with Federation starships, but it's my impression that all of the starfaring cultures at roughly the Federation's tech level are using substantially the same FTL technology (for instance, everyone seems to need dilithium crystals it's universally referred to as "warp drive" as far as I know, and ships of different navies can encounter each other at FTL velocities) so I'd be inclined to assume it applies across the board in the absence of evidence to the contrary.

Caveat 2: Spock's World is an official tie-in novel, but not an adaptation of a TV episode or movie, so this is probably not 100% canonical; I don't know exactly how that works. However, I doubt a more detailed in-universe explanation is available.

  • Adding a quote would take this answer from good to great
    – Valorum
    Commented Aug 14, 2014 at 17:55
  • @Richard I regret, I haven't had a copy of that book since I moved out of my parents' house for good, which was in 1997.
    – zwol
    Commented Aug 14, 2014 at 17:58
  • I'm happy to hunt out the quote if you want.
    – Valorum
    Commented Aug 14, 2014 at 18:01
  • @Richard If you have a copy, I believe it was in the scene where the Enterprise is throwing its traditional "we're all back from vacation" party, which is interrupted by needing to rendezvous with another ship to pick up Sarek.
    – zwol
    Commented Aug 14, 2014 at 18:04
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    @Xantec: The dilithium crystals are a core component of the way the energy is generated on Federation ships. They are not integral to the concept of warp drive or warp engines/nacelles. Also, note that, for example, Klingon Birds of Prey do not have obviously visible warp nacelles, either, nor do Cardassian ships. Ferengi warp "nacelles" seem to be integrated into the hull on the D'Kora class marauders, and the Vulcan warp drive seen in various 22nd century ships is not contained in a "nacelle", but in a circular structure. Commented Aug 15, 2014 at 13:56

In Enterprise, Season 2, Episode 16, when the Tholian ships go to warp, they produce similar flashes (although differently colored). This happens around 38:54 into the show (Netflix timing)

enter image description here enter image description here


I've always seen it as a light barrier equivalent of the sonic boom when a craft crosses the sound [speed] barrier.

I can't think of how else to explain it. Other ships don't not doing it seems to me like artistic license.

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    Except that's a misconception: a sonic boom is not a momentary thing that only happens at the moment that a craft crosses the sound barrier; it is in fact a constant phenomenon that follows the path of the craft. Commented Aug 14, 2014 at 11:11
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    That would explain, why the producers would consider it a good idea (giving the audience something to relate to [@LightnessRacesinOrbit: And to that end it suffices if viewers share that misconception]). But it doesn't explain it in-universe and I guess that is the question...
    – Einer
    Commented Aug 14, 2014 at 11:22
  • This would have been my answer as well. @LightnessRacesinOrbit Even though the boom is constant, the same article you referenced indicates that it is experienced at a given moment in time by a given observer, so the flash of light would be an appropriate analog after all. Commented Aug 14, 2014 at 13:26
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    @ChrisSunami: Yes but then you'd see it all the time across the "horizon" as you witnessed passing ships in warp. Okay space is big, but at least near busy "shipping lanes" and whatnot, or .. well .. hmm Commented Aug 14, 2014 at 14:08
  • Lightness - wrong! (In as much as "entirely hypothetical physics can be 'wrong!'..." :) ) If something is outside your spacelike curve, (eg, wikipedia/Spacetime) in fact it is beyond the edge of the observable universe; something going FTL is not "passing you"; it would be elsewhere - exactly like real cosmologists/astronomers can't see "beyond" the edge of our universe (where redshift evaporates). There's NO analogy to a sonic boom (which happens along a line in space). Indeed the reason the flash stops once the craft gets up to speed (FTL!) is the craft is gone from our spacetime...!
    – Fattie
    Commented Aug 17, 2014 at 14:02

The polyluminous burst is to warp speed what the sound barrier is to Mach speed. It's a visual burst that signifies an object has moved from subluminal to superluminal speeds.

So why do we not always see one when an object goes to warp? As it happens -- not all warp drives are created equal! (or at least, not all warp drives are depicted equally) The warp effect has not been consistently depicted throughout the series - even within TNG-inspired spinoffs. Here's a brief revue of the various ways the Enterprise (and a handful of other ships) have been shown going to warp over the last few decades.

Ships in TOS-era movies don't really 'stretch and boom' like TNG ships; their warp drive mainly consists of showing that any light-producing sources on the ship leave afterimages as the ship moves. Meanwhile, TNG typically shows the 'stretch and boom' effect, probably visually suggesting that whole squishy-squashy Alcubierre effect that people are fond of pointing to when dealing with "real" superluminal travel. Nemesis is an odd duck here; Enterprise-E apparently no longer needs to stretch before running, instead emitting twin smoke trails with an initial puff before creating a light burst.

But even within TNG, there are instances of ships playing by different rules. Take a look at the opening shot of Redemption, Part II:

The Klingon ship apparently uses the old TOS-movie era light-trail effect. Now, the scene itself leaves a lot to try to discern -- but I believe this is an indicator of older technology at work. Indeed the Klingons are not usually known for their warp drive innovations, so it's somewhat believable that they prefer to employ the same ancient junk. (this would render Birds of Prey as way, way slower than TNG era craft - though it's not really hinted at onscreen, old warp was the cube of the warp factor times c whereas TNG era warp speeds are the warp factor to the power of 10/3 times c. this would make a BoP laughably sluggish at high warp speeds!)

Additionally there's a moment where the Borg cube from Best of Both Worlds Part 2 jumps to warp speed. The cube doesn't stretch or create a burst or leave a light-trail or anything, really -- but then again, it's only onscreen for a second.

So what does it all mean?

The only real constant is change with the warp effect. Given the majority of the visual cues as being "era-specific" - TOS looks a certain way, TNG looks another, and JJ-verse looks like a trip through slipstream from Gene Roddenberry's Andromeda - really the only thing worth taking away from it is that it can (somewhat) point to the craft's make, model, and year of manufacture.

Sort of. :/


A thought... could it be the relativistic passage of time (us not moving versus the ship moving at and beyond light speed. Would photons reflected off the ship be occurring over a longer period of time (again to us) the faster it travels? They would not slow down as they always travel at the speed of light, so there would be a lot more of them. A friggin' lot of them when the ship hits light speed, hence the massive flash.

  • Welcome to the site, I recommend you take our tour to see what kind of answer we are looking for. Specifically, we like answers that have sources to back them up, as opposed to speculation. If you ever saw or read anything that led you to the interpretation you presented in your answer, I encourage you to edit it in for the rest of us.
    – amflare
    Commented Dec 9, 2017 at 19:39

It's a rendering gimmick to give the effect more snap. It catches the viewer's eye and engages them to the show. It aids in the suspension of disbelief. More engaged viewers, more advertising viewed, more revenue. They do it for the exact same reason Seven of Nine was added to Voyager.

If you want physics: It imparts momentum on the cash in your pocket toward the studio's coffers.

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    The answer to every single question of this type is "because it's a special effect". The fun comes in trying to work out an 'in-universe' reason.
    – Valorum
    Commented Aug 15, 2014 at 13:11
  • To agree with Richard .. cynicism is admirable and always refreshing, but indeed the question seeks an "in-canon" answer. For example, the "actual" answer (in DrChandra's sense) may be something like - this is just an example - "the person who invented that particular effect was known to director X and hence director X used it." But that would not be the answer to the question "what is the in-canon reason?"
    – Fattie
    Commented Aug 17, 2014 at 13:55

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