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A comment on Room Temperature Superconductivity Found in Graphite Grains. Parent comment

Re:Room Temperature Superconductivity Found in Graphite Grains by yk on Friday September 14, 2012 @12:37PM (#4522517)
For example, super conductors can 'freeze in' magnetic fields. This means, that the super conductor can essentially only move along the field lines. ( Found this video [1], which shows the effect.) With the same effect you can 'levitate' objects, for example a bookshelf. So there would be endless possibilities for novelty toys.

[1] https://www.youtube.com/watch?v=TeS_U9qFg7Y

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Re:Room Temperature Superconductivity Found in Graphite Grains by ajuc on Friday September 14, 2012 @01:14PM (#4522727)
Won't regular electromagnet work the same way, just constantly use energy?

EDIT: ok, nevermind, it won't.

http://en.wikipedia.org/wiki/Magnetic_levitation http://en.wikipedia.org/wiki/Earnshaw%27s_theorem

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Re:Room Temperature Superconductivity Found in Graphite Grains by tgb on Saturday September 15, 2012 @09:08AM (#4526012)
Earnshaw's theorem only applies to static electromagnetic fields. An electromagnet coupled with some sensors and a computer can give feedback to make stable levitation. But, as you said, it would constantly use energy.
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