Re: is levitation possible? How?

Cool Question Graham or should I say cold ....

Levitation is possible using magnetic fields. One of the coolest (coldest) demonstrations of levitation is performed by placing a permanent magnet above a superconductor. The magnet floats above the superconductor because the superconductor does not allow the magnetic field of the magnetic to penetrate it. This causes a force to be exerted upon the magnet -- and if it is strong enough to counter the downward pull of gravity the magnet will float. The problem with this is that superconductors need to be cold to work. Even the 'highest temperature' superconductors require a liquid nitrogen bath to keep them cold -- that is 77 degrees Kelvin (really really cold).

Recently scientists at the University of Nijmegen have been able to levitate a frog (among other things) in a really strong inhomogeneous magnetic field at room temperature -- much better for survival of living beings. The method uses a very high magnetic field (20 Tesla = about 40,000 the Earth's field) to generate a magnetic force opposed to the force of gravity due to the molecular diamagnetism. Just about everything has some diamagnetism. This solution is really counter intuitive. Scientist would have believed that a much stronger field would have been needed.

As quoted from Oxford Instruments "Research Matters" Autumn 1997:
Diamagnetic levitation may bring space experiments down to earth. Recent experiments on levitation and very inhomogeneous magnet fields at room temperature point to the existence of a whole research area which is still relative unexplored. This opens up exciting possibilities such as the simulation of microgravity and the development of frictionless bearings. The experiments captured the public's imagination when frogs were levitated. The "flying frogs" were given worldwide coverage by the media, who spotted the possibility of human levitation.

This levitation can be used to simulate low gravity and could eventually compete with space launches for gravity experimentation.

Perhaps the next technical breakthrough will be to make a strong field in a volume big enough to levitate a person -- that is quite a challenge.

Sincerely,
Tom Cull