Fun with Physics: What if “The Force” Could Be Used as a Sustainable Energy Source?

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I’m going to assume you read XKCD, because you’re at least a little techy, a little geeky, and have the internets. You may not have noticed, though, that Randall Munroe of XKCD fame has a new website called What If?, at which he answers fun and wacky hypothetical questions with good physics every Tuesday. The topics thus far have ranged from “What would happen if you tried to hit a baseball pitched at 90% the speed of light?” to “What if everyone who took the SAT guessed on every multiple-choice question? How many perfect scores would there be?” to “What would happen if you were to gather a mole(unit of measurement) of moles(the small furry critter) in one place?

Last week’s question, though, is destined to be one of my favorites for a long time: “How much Force power can Yoda output?” In other words, what sort of output could Yoda produce as a renewable energy source?

Yoda’s greatest display of raw power in the original trilogy came when he lifted Luke’s X-Wing from the swamp. As far as physically moving objects around goes, this was easily the biggest expenditure of energy through the Force we saw from anyone in the trilogy.

The energy it takes to lift an object to height h is equal to the object’s mass times the force of gravity times the height it’s lifted. The X-Wing scene lets us use this to put a lower limit on Yoda’s peak power output.

First we need to know how heavy the ship was. The X-Wing’s mass has never been canonically established, but its length has—16 meters. An F-22 is 19 meters long and weighs 19,700 lbs, so scaling down from this gives an estimate for the X-Wing of about 12,000 lbs (5 metric tons).

Next, we need to know how fast it was rising. I went over footage of the scene and timed the X-Wing’s rate of ascent as it was emerging from the water.

The front landing strut rises out of the water in about three and a half seconds, and I estimated the strut to be 1.4 meters long (based on a scene in A New Hope where a crew member squeezes past it), which tells us the X-Wing was rising at 0.39 m/s.

I won’t spoil the rest, because it’s a delightful read, with interesting observations about power consumption, geeky obsession, and the relative energy needs of cars and neighborhoods, but I absolutely adore the punchline:

But with world electricity consumption pushing 2 terawatts, it would take a hundred million Yodas to meet our demands. All things considered, switching to Yoda Power probably isn’t worth the trouble—though it would definitely be green.

Read: [XKCD: What If?]

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