How powerful are photon torpedoes, really?

[Sionnach Glic]

As the title says, how powerful are photorps? For the purposes of this debate, let's stick purely with observed canon evidence from the shows and movies. Non-canon sources, such as the TM, are not admissable in this debate.

[Captain Seafort]

The only events I can think of that would allow calculations would be the maximum yield of Enterprise's photonic torpedos being able to "put a three kilometre crater into an asteroid", and the Pegasus asteroid that would have required the full arsenal of the E-D to destroy it (250 torps, ish). SDN's asteroid destruction calculator would be a useful tool for that aproach. Unfortunately my computer's been giving me grief for months so I can't get onto the main SDN site.

We could also approach the problem by looking at the observed shielding limitations of various ships and working back.

[Sionnach Glic]

How big was the asteroid in Pegasus?

[Captain Seafort]

How big was the asteroid in Pegasus?

About 12 1/2 km by 8 1/2, by my calculations here.

[Sionnach Glic]

Okay, cool. I'll plug some numbers into SDN's calculator and see what I get.

Since the calculator assumes a spherical asteroid, this'll be off by a bit. I'm going to assume that a ten kilometre spherical asteroid would have roughly the same mass, though it'd probably have quite a bit more.
My second assumption is that they're aiming just to break the asteroid up (given that they were searching for a ship inside it, this makes sense).

Total energy required to fragment it is 1 gigatonne.
Divide that by 250 (the number of torps), and we get a figure of 4 megatonnes (I think). This figure seems to go fairly well with what we see torps doing to ships.

[Graham Kennedy]

200 isotons.

[Sionnach Glic]

Per torp?

That's rather.....unimpressive. Doesn't 'iso' just mean 1?

[Mikey]

"iso-" in Star Trek actually means "this is a generic prefix we use to make something sound all futuristic and science-y."

[Duskofdead]

As the title says, how powerful are photorps? For the purposes of this debate, let's stick purely with observed canon evidence from the shows and movies. Non-canon sources, such as the TM, are not admissable in this debate.

If we go with observed evidence, then in general, photon torpedoes are really, really weak. They're on par with a strong handheld weapon or something. The fact that a relatively tiny portion of ship shields "light up" to deflect the energy explosion from a photon doesn't inspire much awe about the scope of their destructive power.

They tend to get tossed like candy in battles. "Serious ships" seem to shrug them off. Only technologically inferior ships seem to have cause to worry. We can assume at least from dialogue that they pack a lot more punch per "hit" than phasers, and that this "hit" is a relatively set amount (given multiple statements in various combat situations along the lines of "a torpedo should do it", "it was that last torpedo", "one more photon should take out their weapons", etc.) but what we can observe, visually, tends to jar out of proportion with this. Photons never seem to have a "big burst" or do any concussive damage, they seem to just hit shields and disappear like any other energy weapon.

[Captain Seafort]

I'm not sure what sort of handheld weapon you're thinking about - torpedoes are pretty consistently in the high kT/low MT range. Slightly more powerful than most modern nuclear warheards, which is very impressive given that they're ubiquitous in Trek.

Of course, these numbers are for TNG-era warheads, which are roughly five times as powerful as their movie-era counterparts.

[Graham Kennedy]

If you want the REAL answer, based purely on the canon evidence?

Photon torpedoes are as strong or as weak as the plot needs them to be.

[Duskofdead]

If you want the REAL answer, based purely on the canon evidence?

Photon torpedoes are as strong or as weak as the plot needs them to be.

Yup. Very inconsistent. They range from hitting a lot of ships in an area of effect to looking like someone tossed a grenade at a starship.

[Duskofdead]

I'm not sure what sort of handheld weapon you're thinking about - torpedoes are pretty consistently in the high kT/low MT range. Slightly more powerful than most modern nuclear warheards, which is very impressive given that they're ubiquitous in Trek.

Of course, these numbers are for TNG-era warheads, which are roughly five times as powerful as their movie-era counterparts.

Yes I understand what you are saying from a dialogue point of view. I was comparing observed visual effect. The visual effect of a photon is typically nothing even close to a nuclear detonation.

[Captain Seafort]

Most of the time nuclear detonations would look pretty pathetic in space - most of the energy would be released as gamma radiation, and since we know nothing of shield mechanics we can't determine yield from the flashes they make.

[Duskofdead]

Even the effect aboardship, though. The ship does not seem particularly more violently shaken by a photon torp than by a phaser impact, even though it should. (Should an energy weapon even CAUSE the ship to shake, unless it made something blow up?)