Ye olde history of perpetual motion machines




Some recent history:


I'm actually shocked those guys are still around.


I love those Steorn guys. They've managed to cling to their "free energy" dingus longer than anyone I know. I'm just surprised that there still are people who take them seriously.

Just one more technical glitch, and we'll reveal everything at the next press conference, I promise.


I, for one, don't know why we all dismiss these attempts. All it takes is one of these innovations to work and we (Earth civilization) will be in golden gravy forever-and-ever. Spandex jackets - one for everyone. And so what if we break some "Law" of thermodynamics. Whaddya gonna do... call the Thermodynamic Police?


Continuing the discussion from Ye olde history of perpetual motion machines:

It's not so much the laws of thermodynamics as the laws of arithmetic. It's established that the energy needed to lift something up is exactly equal to the energy gained by letting it drop back down, minus losses due to friction. (And the same holds true for motion through magnetic fields, etc.) If the laws of arithmetic are correct, then every combination of energy sources and equal energy sinks will always add up to zero.

Perpetual motion machines involve setting up a complicated system with lots of moving parts and then "forgetting" to add in one of the energy sinks.

People get upset about threats to change the laws of arithmetic because they know on a gut level that no matter what changes were made, they'd somehow wind up owing back taxes and mortgage interest because of it.

Now, what would be interesting is a perpetual motion machine based on some kind of exotic matter that's light when it's lifted up, but becomes heavy when it falls down. Nobody ever builds those.


The Martians in Kurd Lasswitz' 1897 novel Two Planets had a dynamically adjustable version of that as the basis of much of their technology. Unfortunately the technical detail was rather limited.


Ah, good old fraudsters, they always have the best lines.

One good rule of thumb: If you have an understanding of a concept that would allow it to create a perpetual motion machine, then you are misunderstanding the concept.

This is why I don't think we'll ever see a gravity shield for instance. We just seem to be trapped by thermodynamics, there's no escape.


I hope you realize that I was kidding in my original post - the call-back to "Spandex jackets" was a clue. But you raise an interesting point. I remember an idea that I heard once about freezers on the floor of the ocean. The freezers would freeze water, and the resulting ice would be attached to some conveyor device that turned as the ice floated towards the surface. The conveyors would turn a generator, generating power to run the freezers and the excess would power our world. Calculations were done and (Yes!) it WOULD work - you would get more power out that you put in. The deficit or friction or the arithmetic factor that enters into all these calculations would be the overall cooling of the entire planet.


Eureka! Infinite energy and fighting global warming at the same time!

(though somehow I think there would be other problems as well)


No - it's still an overall heating. Freezers don't create cold or remove heat - they just move the heat somewhere else (usually a condensing coil or other heat exchanger).

Inefficiency will mean the net effect is heat, entropy and listlessness followed by ennui.


(yawn) tl:dr


Actually, the real loss of efficiency is is paying some poor slob to sit on the bottom of the ocean and keep pushing the "ice" lever on the front of the freezer door. And he keeps dropping the glass.


Well, of course not. All of that stuff has floated away.


My calculations show that application of a simple graphic significantly increases the coolness factor of the ice machine:


Disclaimer: The "gravity engine" is not something I have studied, and the builders do not claim it is a perpetual motion machine (it's said to draw power from the moving mass of the earth, like hydro turbines and windmills do, which is not exactly the same thing.) I was just struck by the similarity of appearance with some of the historical devices and thought y'all would like to see it!


The page calls it a "Gravity Engine". It's certainly impressive looking. I'm still dubious on how it's supposed to harness gravity however. Also, their copy says:

Technology was completely developed by our Company and consists in a continuos[sic] movement with some extra energy that can be taken, in a continuous and perpetual mechanic movement.

I would like to see it in action, because my default position on this is strong skepticism.


Yeah, me too! (Of course that's my default position on nearly everything.)

The line between claims of "perpetual motion" and "motion that will continue as long as the Earth endures" can be pretty thin.


Harnessing the rotation of the Earth is certainly valid in theory, but a practical example is really hard to envision. At last one that generates the 30kW they quote. That page has elaborate scam written all over it.

An example of a machine that could harness the Earth's rotation for near-unlimited power:

  1. Build a space elevator, with the far end past Geosync orbit and hooked to a counterweight.
  2. The Earth side is at the north or south pole, and it attached to a generator with a LOT of upgearing.
  3. As the Earth rotates it spins the generator. The counterweight is pulled towards Earth, but the centripetal forces on it should keep the line taut and straight.

This however would be by far the least practical energy system ever devised. Any other renewable energy source is going to blow it out of the water in a cost efficiency analysis.


You can't do geosync at the poles. But that doesn't really matter; you don't actually need the generator or the gearing.

When STS-46 and STS-75 dragged long wires through the earth's magnetic field from orbit, the amount of energy collected was staggering; the tether's drag on the spaceship was being very effectively converted to electricity (until the tether fried).

Anyway, there's lots of ways to convert part of the earth's motion to electricity - I already mentioned windmills and hydro turbines, of course. But it's hard to find contraptions as aesthetically awesome as the gravity engine! Something about that Rube Goldberg/Heath Robinson pile of levers makes me wish it can work, although I highly doubt it does.