By not posting all three lines or showing it to be the correction of an earlier post you had made, you implied I said both were true. I now recognize that the dropped phrase in your original quote was a case of source conflict. You credited the quote as being from the ST:Encyclopedia and when I searched to confirm it found only the memory alpha version of that encyclopedia which makes no mention of the line, so I went to StarTrek.com and saw the expanded version. I presumed incorrectly that you had intentionally dropped the bit about phasers being limited to c to avoid admitting I was correct in saying phasers couldn't exceed c except within a warp field. I apologize for that.
When asked why I felt Trek weapons couldn't go FTL I responded...
Number two, photon torpedoes are sublight by their own admission. A torpedo has neither a warp core or nacelles to generate a warp field. And this is where I point out how technobable is used to ignore the fact for entertainment purposes..
and posted a quote from the only article the I could find which gave a detailed explanation of how the torpedo functioned. Startrek.com doesn't even try to explain the conflict. No one here has attempted to explain it either, just keep repeating they can because they can.
http://www.deepspace12.com/torpedo.htm <--quote source, I felt it had the best explanation of the workings.
http://www.ex-astris-scientia.org/inconsistencies/treknology-weapons.htmThe only two sites I found when I search for "photon torpedo" which attempt to explain the reason why something incapable of generating a warp field can go FTL. Notice in the ex-atris article the quote from the TNG tech manual. I believe that is probably the source used by both sites.
Have they ever explained on-screen how torpedoes can go FTL or is it just one of those things no one talks about?
I dismissed the class-8 probe because it was a plot device. Why could it go FTL when it was essentially an empty shell? Because the writers needed it to. What was the explanation as to why it could go FTL given in the episode? There wasn't one, it could because they needed it to. Any other episodes mentioning the probe or it's abilities? No, it was a plot device see questions one and two.
Just google "warp sustainer unit". I'm betting though that the ultimate source of explanation is the TNG:TM. Okuda had to somehow explain the impossible and invented the WSU to do it.
You make an excellent point with the Tholians. The series people have never given out anything, to my knowledge, about how the Tholian stuff works. This is a good thing because if you don't try to explain how it works you don't have to worry about painting yourself into a corner and being forced to invent some technobable solution for it. It's beside the point though because it's not a question of how Tholians or the First Federation or [insert mysterious alien race of the week] manipulate warp fields if they use warp at all (borg) and what the restrictions on them are, it's how does the Federation. Without "they can because they can" or "the mystical WSU" torpedoes function "realistically" given the meaning of "reality" as defined by the show and are restricted to sub light speed.
You say they can, I say they do because it's television, but would not be able to. Can we just agree that we've already spent way too much time on the subject an put it behind us? I'm beginning to worry I'll wind up at a Con somewhere getting yelled at by Shatner for asking him the code the safe in his quarters.
Perhaps this'll draw it to a close,
Q: Can photon torpedoes travel FTL and if so how?
A: Yes, whenever a writer has a plotline which requires a warp speed firefight, transportation of an operative in a way that allows her to make a cool entrance on the transporter pad or the need to torpedo Risa from the Delta Quadrant then he/she can ignore anything mentioned regarding the generation of warp fields using Federation technology and just make it happen so long as he/she remembers not to include any dialog explaining the inconsistency.
Probably not.