# Star Wars lightsabers: how are they powered?
**URL:** https://boards.straightdope.com/t/star-wars-lightsabers-how-are-they-powered/357443
**Category:** Cafe Society
**Created:** [May 19, 2006, 7:15pm UTC](https://boards.straightdope.com/t/star-wars-lightsabers-how-are-they-powered/357443 "2006-05-19T19:15:27Z")
**Posts on this page:** 3
**Page:** 3
### Author:  [@Zakalwe](https://boards.straightdope.com/u/Zakalwe)
#### Post date: [June 2, 2006, 8:36pm UTC](https://boards.straightdope.com/t/star-wars-lightsabers-how-are-they-powered/357443/41 "2006-06-02T20:36:13Z")
> [@Chronos](#):
>
> And physics nitpick, but “gigawatts” are a unit of power, not of energy. How much power a cell can supply tells you nothing about how long it’ll last. A unit of energy might be “gigajoules”, or “gigawatt hours” (that is to say, a 1 GWhr source could continue outputting 1 GW for an hour, or 1 watt for a billion hours, or 1000 watts for a million hours, before running dry).
Well, given that this is Star Wars, we can assume that the power output is probably measured in “gigawatt parsecs”.
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### Author:  [@Rachael\_Rage](https://boards.straightdope.com/u/Rachael_Rage)
#### Post date: [June 2, 2006, 9:56pm UTC](https://boards.straightdope.com/t/star-wars-lightsabers-how-are-they-powered/357443/42 "2006-06-02T21:56:51Z")
> [@H3Knuckles](#):
>
> Sorry to necropost, but excuse me?
>
> I don’t remember **Yoda dying** anywhere in _Empire_, I’m pretty sure there was an extended scene in \*Return where Luke returns to Dagobah to confront Yoda, and then Obi-Wan’s Ghost about their deception as to his relationship with Vader. 😛
>
> While _Shadows_ does a good job of explaining things, it really wasn’t necessary, as the perfectly logical assumption would have been that Yoda taught him, either during his first visit to Dagobah, or perhaps during a hypothetical return trip prior to _Return_.
Oops. :smack:
I think “Jedi” does imply that Luke’s return to Dagobah in the film was his first since he left for Cloud City, when he says to Artoo “I have a promise to keep to an old friend.” But, it does leave the option open that he may have been back before. It would certainly make more sense, since the entire time he spent on Dagobah in “Empire” - if we’re comparing it to Han & Leia’s experiences in the asteroid field and in Cloud City - fell somewhere between a couple days and a few weeks. That’s not much time for Luke to “already know you, that which you need.”
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### Author:  [@Sleel](https://boards.straightdope.com/u/Sleel)
#### Post date: [June 5, 2006, 2:34am UTC](https://boards.straightdope.com/t/star-wars-lightsabers-how-are-they-powered/357443/43 "2006-06-05T02:34:50Z")
> [@Chronos](#):
>
> Once, but I’m not sure where Energizer Bunny commercials fit in the hierarchy of canon.
>
> And physics nitpick, but “gigawatts” are a unit of power, not of energy. How much power a cell can supply tells you nothing about how long it’ll last. A unit of energy might be “gigajoules”, or “gigawatt hours” (that is to say, a 1 GWhr source could continue outputting 1 GW for an hour, or 1 watt for a billion hours, or 1000 watts for a million hours, before running dry).
You’re right, of course. Aaand, **Zakalwe** ’s probably also right about SW-verse units.
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