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A phaser fires a nadion particle beam at its target. That sounds like inertial mass is involved so it doesn't reach light speed. Semi-out-of-universe we see how fast a phaser beam is: I'd estimate something around 80 kph. You can see it moving with the naked eye. But that might be just a way to tell a story; to establish causality to the audience: "Look! First the beam is here, now it's here, now something's exploding." So the audience knows why the enemy ship explodes: It was a phaser beam, going from here to there. So maybe we are just shown a "symbolic slo-mo" to let us know what's happening.

Are there any in-universe insights on how fast a phaser beam travels? E.g. can I escape (escape, not evade) one on full impulse?

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My understanding is that a phaser beam travels at the speed of light. You could escape it, but you'd have to be traveling at warp speed. –  Chahk Apr 14 '14 at 19:56
Don't apply real Physics.. It can travel even faster than light.. –  SS-3.1415926535897932384626433 Apr 14 '14 at 22:06
@SachinShekhar - The canon(ish) quote is that they travel at lightspeed unless being fired from a ship travelling at warp. –  Richard Apr 14 '14 at 23:51
@Richard No, I am saying it "can" travel FTL in sci-fi. The question is good except that inertial mass involvement thing. –  SS-3.1415926535897932384626433 Apr 15 '14 at 5:42

4 Answers 4

up vote 15 down vote accepted

The "Voyager Technical Manual" (written by longtime Star Trek production staffers Michael Okuda and Rick Sternbach as an 'aide-memoire' for potential scriptwriters) specifically states that phaser beams travel at the speed of light.

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This is backed up by another quote from the earlier "TNG Technical Manual" which clearly states that the beam travels at "c"

TNG Technical Manual

Given that full impulse is supposedly well short of the speed of light, the short answer to your question is "no, you cannot escape a phaser beam by travelling at sublight speeds".

Travelling at warp speed would be considerably more effective against a foe travelling below lightspeed since you would simply outrun the beam (unless the phaser is fired from a ship travelling at a similar warp factor).

Out-of-universe (e.g. from a TV production standpoint) phaser beams do often travel considerably slower.

As the video below shows, beam speed is wildly inconsistent. At the slowest they seem do seem to be moving about a couple of feet per frame. At the fastest, the beam is instantaneous from one shot to the next

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That is exactly the answer I was looking for. But if you don't mind I'd like to wait for a possible second opinion before marking it as the right one. To me there is so much consitency standing or falling with this... –  Einer Apr 14 '14 at 20:33
They also travel significantly faster than the speed of light. There are several encounters between Voyager and Kazon ships traveling at warp when phaser fire is exchanged. Or is that a consequence of the warp field? –  Dacio Apr 14 '14 at 22:49
@Dacio - From the same source; - Phasers can be used at warp –  Richard Apr 14 '14 at 23:50
Doesn't change the fact that, from my sub-light observation frame, those phasers were traveling above light speed. –  Dacio Apr 15 '14 at 0:05
@dacio - Apparently if you've got the right technology you can strap a torch onto a speeding train and have it go faster than lightspeed. –  Richard Apr 15 '14 at 0:09

The ST:TNG Technical Manual's description of phaser operation clearly states that the beam will "travel at c to the target".

Disclaimer: I do not have the book in my possession. Quoting from the Google books version.

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Since characters in all of the Star Trek series are shown ducking from and dodging phaser beams, it would seem that their speed is somewhat less than the speed of light and often slower than the speed of a bullet from a projectile weapon. If,as the Voyager Technical Manual states phaser are indeed light speed or even relativistic speed weapons missing with them or dodging their beams would be impossible.

Simply put when someone aims and fires a phaser, there is no way for it not to strike its intended target unless the weapon was deliberately aimed away from them. The weapon has no recoil and it would be as if you shined a flashlight at someone (e.g. you can’t miss them)

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That has been my thinking too, but think about it: When you see someone pointing a flashlight at you and you see that he is about to activate it, you can always jump behind a rock. If you detect a phaser lock you can still do evasive maneuvers. –  Einer Apr 15 '14 at 5:15
@einer - Ship-to-ship evasive maneuvers are intended to present as small a target as possible and to prevent a prolonged exposure to incoming fire. –  Richard Apr 15 '14 at 5:35
Then why are there cases where someone with hostages can force others to lower their phasers? They can aim their phasers to disable arms or weapons of the hostage keeper? –  dh87 Aug 23 at 5:37

A phaser blast travels at warp fifteen, the maximum speed possible in the Star Trek universe without going into time warp. In the original series "The Ultimate Computer", the M5 computer easily destroys two Federation Star Ships while the Enterprise is traveling at warp four. In the original series "Journey to Babel", Captain Kirk destroys a scout ship with a phaser blast that is traveling at warp ten.

Unfortunately, there have been many writers of Star Trek since the original series that had very little understanding of the firepower of the original Enterprise and they weakened the Enterprise significantly in the movies and the Next Generation. In the original series "The Changeling" the Nomad robot repeatedly attacks the Enterprise with energy blast that are each equal to ninety photon torpedoes. The original Enterprise was far more powerful than the future ships that the writers weakened. The original Enterprise's photon torpedoes were dirty bombs that could destroy a city.

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The first paragraph seems to have some bearing on the question. The second paragraph has little or no bearing and is basically a rant. –  Richard May 13 at 18:16
By no means was it meant to be a rant. I was simply stating factual events that took place with Gene Roddenberry's original version of Star Trek. The writers after him changed a lot concerning the Enterprise's firepower and endurance making it difficult for an accurate answer to the question. I simply went back to the old episodes for the best answer I could give. –  Ray May 13 at 18:34
So you're just going to ignore that Roddenberry was intimately involved in the writing, production and direction of TNG? –  Richard May 13 at 18:37
As well as utterly ignoring that writers were presented with a very comprehensive show "bible" that explained the capabilities of the various bits of tech lying around? –  Richard May 13 at 18:38
Of course Roddenberry was involved. They had to lower the firepower so they could have an awesome Star ship battle in Star Trek 2 The Wrath of Kahn. The bottom line is the original 1968 Enterprise from the original series would totally blow away Picard's flying window pane Enterprise. They had to lower the firepower to make great Star ship battles with today's special effects. –  Ray May 13 at 18:46

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