Comment by mikewarot
9 hours ago
So, if you use eddy currents to delay the phase of an exciting field long enough that the object those eddy currents are inside of can spin more than 90 degrees, the response eddy current fields now AID instead of opposing the original field?
This sounds quite a bit like what Steorm[1] was doing years ago. If ultraconductors[2] worked, you could actually build a mechanical device that had losses low enough to actually gain energy once a critical speed were obtained.
[1] https://en.wikipedia.org/wiki/Steorn
[2] https://patents.google.com/patent/US5777292A/en
(Claim 7 is for material with a conductivity of 10^11 S/cm, which is 150,000 times better than copper)
> This sounds quite a bit like what Steorm[sic] was doing years ago
Steorn was a scam, and they never actually showed anything off. The only thing they did was rob some investors.
> If ultraconductors[2] worked, you could
Not familiar with that idea, but this construction sounds a bit like: "If only you had an (infinitely) rigid rod, you could push one end to communicate faster than lightspeed."
Or in balder terms: "If only we had a subtly impossible component, we could make a blatantly impossible machine."
I am somewhat curious where the math on a perfect rigid rod breaks down (that is, where does the 0 end up under the line)
My gut instinct is you’d really need perfect incompressibility such that pushing one end of the rod would propagate the pressure wave to other end instantaneously. In other words, you have to make the speed of sound faster than the speed of light. I have no idea what the physical construction would look like. Maybe a string of singularities lined up and touching (hey, there’s your 0!) without tearing spacetime apart?
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I think the math is fine, but a perfectly rigid rod cannot exist in our universe, so there's no paradox, even though it would let you send messages faster than light. It's like calculating how strong of a hydraulic press you'd need to compress matter into neutronium in your garage, or claiming that if a spaceship could travel at 2x light speed, then it could fly its way back out of a black hole.
There simply are no such things as rigid bodies in this universe. Everything is composed of particles that act on each other with forces, which take time to transmit the information that something is pushing on the other side.
My guess is that the Pauli exclusion principle would ultimately come into play, the same thing that keeps stuff from falling through other stuff. Electrons will shove other electrons out of the way, which isn't a lossless process or an instantaneous one. So a perfectly rigid rod would run afoul of special relativity if you pushed on one end.
So a perpetual motion device!?