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I was watching ESB recently and noticed something when Luke loses his lightsabre during his fight with Vader; the sabre seems to spin around a center a few centimetres above the hilt. This gets even more clear if you watch it frame-by-frame. Now, if the blade had been massless, the center of mass would be roughly in the center of the hilt, and the entire sabre would have spun around that, but it doesn't. And there is also RotJ, when Vader throws his sabre. It, too, doesn't seem to revolve around the hilt. But it's harder to tell in this case, because of the camera angle and the sabre only being picture for a few frames.

So how can this be made consistent with the idea that the blades have no mass? And where does this idea of massless blades come from anyway?

I'd assume that it's an oversight, since in RotJ when Vader throws his sabre at Luke, it does indeed spin with the centre of mass in the middle of the hilt.

If one wishes to assert the blades have no mass, one could simply suggest the Force users were manipulating the sabers during their flight.

Robert Walper wrote:If one wishes to assert the blades have no mass, one could simply suggest the Force users were manipulating the sabers during their flight.

Not in the case of ESB above, dullard. Vader clearly was in RotJ, but Luke's sabre was knocked out of his hand and simply landed on the floor.

I still claim it's an oversight. I'd assume that it's not always perfect weighing a weapon so that its blade appears massless.

Perhaps the aerodynamic resistance of the blade has something to do with it. The blade obviously interacts with air, otherwise it would not make that noise.

also in TESB the saber was still on Luke's hand when it spinned.

When the blades are in use by their wielders, they are not depicted as being massless. There is clearly weight behind their motion.

That's because of filmic and physical limitations. Or would you like to devise a praticle way for lightsabre blades to appear massless while still being weildable?

Spanky The Dolphin wrote:That's because of filmic and physical limitations. Or would you like to devise a praticle way for lightsabre blades to appear massless while still being weildable?

Suspension of disbelieve needs to be abided by though...

So do the boundries of reason and practicality, dullard.

Spanky The Dolphin wrote:So do the boundries of reason and practicality, dullard.

Suspension of Disblief is obviously going to imply that regardless whether or not lightsaber blades are "supposed" to possess mass, they certainly behave like they do.

Spanky The Dolphin wrote:That's because of filmic and physical limitations. Or would you like to devise a praticle way for lightsabre blades to appear massless while still being weildable?

Irrelevant. This is artist's intent vs. SOD, and SOD wins. Period. Or shall we go talk to the ILM boys about whether or not they meant to composite the TL effects to that things react before they get hit?

Darth Wong wrote:Perhaps the aerodynamic resistance of the blade has something to do with it. The blade obviously interacts with air, otherwise it would not make that noise.

I suppose that's possible. However, if aerodynamic resistance can make the blade appear to have mass when thrown, shouldn't it also make it appear to have mass when swung normally? If so, that could explain why the sabres are wielded as if they had mass in films. But it would also invalidate the claims that lightsabre are hard to wield because the blades have no mass...

Lord Revan wrote:also in TESB the saber was still on Luke's hand when it spinned.

No it's before that; when they're still in the freezing chamber.

Dooey Jo wrote:

Lord Revan wrote:also in TESB the saber was still on Luke's hand when it spinned.

No it's before that; when they're still in the freezing chamber.

that's the scene I'm talking about, Vader after all knocked the saber of Luke's hand.

Spanky The Dolphin wrote:That's because of filmic and physical limitations. Or would you like to devise a praticle way for lightsabre blades to appear massless while still being weildable?

Some scenes use only the hilt and rotoscope the blade in entirely, this is time consuming though. In those scenes, the lightsaber prop will simulate a massless blade.

Yeah, I was thinking the same.

the blade suppossedly has some gyroscopic quality to it that makes it difficult to wield. This could account for why it behaves as though it has mass.

Spanky The Dolphin wrote:That's because of filmic and physical limitations. Or would you like to devise a praticle way for lightsabre blades to appear massless while still being weildable?

Aerogel might do it. But I see what you mean.

Some might be massless some might not be.. considering a lightsaber is pretty much a custom-built object, there's no reason to assume they all neccesarily operate the same ways (much like blasters in fact.)

Isn't that going a little too far?

Ender wrote:the blade suppossedly has some gyroscopic quality to it that makes it difficult to wield.

Where's that from, anyway? I keep seeing it mentioned, but I don't ever recall seeing a source for it.

I don't know where it originally came from, but:

The Star Wars Visual Dictionary, Page 6 wrote:Lightsabres

...While the pure energy blade has no mass, the elctronmagentically generated arc wave creates a strong gyroscopic effect that makes the lightsabres a distinct challenge to handle.

Lord Revan wrote:that's the scene I'm talking about, Vader after all knocked the saber of Luke's hand.

Oh, okay then. But the sabre keeps spinning after it's knocked from the hand. How it was knocked out of the hand doesn't really affect the way it will spin (as in making it spin around a different center), just the speed and direction. Just try putting a piece of lead or something on the tip of a pencil and throw it; no matter how you do it, it will still spin around the combined mass-center of the pencil and the lead.

How bout some goddamn pictures or short mpegs?

The scene in question:



If someone wants to make an animated gif, I can also post the individual frames for you to download. Unfortunately, I am late for a game so I didn't have time to look at the scene in detail and offer any comments. Hope this helps.

Off topic: I love the composition and lighting in this scene.