Magnetic levitation of vehicles vs anti-gravity

[dbaezner]

I'm trying to provide a simple technology for vehicles to float above the ground in a sci-fi story I'm writing. Star Wars landspeeders use anti-gravity, which I suppose I could use as well. It's not unique to Star Wars, although it was popularized by that saga and I was hoping to do something different.

I was wondering what the future holds for magnetic levitation. I know it's already used for some trains, but was wondering what the physics problems would be in trying to float vehicles on a strong magnetic field. Obviously the field would have to be embedded in roadways and parking lots, which limits is use. In particular, though, I was wondering what such a strong field would do to people trying to move about near roads and parking lots. I'm guessing a lot of car keys are going to be stuck to the ground. :-) What about health effects?

Also, if anyone can suggest other options, I'd love to hear them.

Thanks

 

[Jonathan Scott]

I don't foresee current 3-phase magnetic levitation technology being practical to extend in that way. I've seen a frying pan levitated using 3-phase current, but if you didn't give it something to fry it would soon become red-hot. Certainly anything involving changing magnetic fields needs to be managed very careful to avoid problems due to induced currents in nearby metal objects.

I was certainly amazed the first time I saw magnetic levitation demonstrated in front of me using the Meissner effect with a superconductor cooled with liquid nitrogen, and if there's some way to extend that to larger scales, that might help, but I still don't see it as practical at vehicle scale.

"Anti-gravity" as such is so far from being scientific that one might as well invoke fairies or magic!

From a scientific point of view, I'd prefer something that explicitly preserves momentum by pushing on something, even if via some unknown form of action at a distance; some sort of short range "repulsor field", which is only effective a short distance above the ground, which must normally be firm (although perhaps it could manage to some extent on soft ground and water, but would tend to blow it away like a hovercraft). Throw in a few words like "phase", "diffraction" and "resonance" and you might have something vaguely plausible-sounding.

 

[krash661]

I was certainly amazed the first time I saw magnetic levitation demonstrated in front of me using the Meissner effect with a superconductor cooled with liquid nitrogen, and if there's some way to extend that to larger scales, that might help, but I still don't see it as practical at vehicle scale.

are you referring to quantum levitation . this below ?

http://www.youtube.com/watch?v=VyOtIsnG71U&list=FLfSW20kus6vS2HUzQ0rXhhA

 

[dbaezner]

repulsor field

Sounds great. Thank you very much.

 

[Jonathan Scott]

are you referring to quantum levitation . this below ?

That's a more advanced version of it, where some of the flux lines get pinned, holding the object in a fixed relative position to the magnetic field, rather than simply excluded, and it's admittedly quite amazing - almost unbelievable.

I saw a live demonstration of levitation using the Meissner effect about 25 years ago by one of the IBM researchers (I can't remember the name) involved in the high-Tc superconductor discoveries and I've seen it done several times since.

Note that both versions of the effect require extremely strong magnetic fields, created using rare Earth magnets. Careful precautions are needed as the force of attraction between such magnets and any loose object made of a magnetic metal could be sufficient to cause serious injury.

 

[Groothouse]

I saw a live demonstration of levitation using the Meissner effect about 25 years ago by one of the IBM researchers (I can't remember the name) involved in the high-Tc superconductor discoveries and I've seen it done several times since.

I won my high school science fair in the physics category for a demonstration and research on superconducting levitation, it is indeed amazing. As far as transportation goes superconducting levitation is already utilized in trains such as the maglev. As for sci fi vehicles you could possibly have a road way made of rare Earth magnets( which is unrealistic seeing as they are rare) and the vehicle's under carriage could be a system of superconductors cooled by liquid nitrogen( all known materials that have superconducting capabilities need to be extremely cold) which would cause it too levitate and also have a cool smoke effect floating on the bottom, also the vehicle would be extremely fast seeing as there would be no resistance past that of air.

 

[I_am_learning]

Tell that room-temperature superconductors are invented and ditch the expensive nitrogen-cooling thing.

 

[Monsterboy]

I found this by ROBERT L. FORWARD , i don't know anything about Theory of relativity so i didn't understand it , may it will do well for your sci-fi story.