Is it possible to exploit the magnetic field of Earth to obtain electricity?
In 1996, NASA experimented with such a thing. It used a tethered satellite (the tether containing metal and being 12.5 miles long), moving through the magnetosphere. It worked under the same principle as a dynamo, where a moving wire in a magnetic field would create electricity. One part of the circuit was the tether itself, where the other was the ionosphere, the distant, ionized region of our atmosphere. This effect is not without cost, however, as the magnetic field opposes the motion of the system, thus lessening its kinetic energy and degrading its orbit. The tether exploited about 1 ampere at 3500 volts of electricity.
See more about this experiment at:
Tethered Satellite System (TSS-1R) by NASA
Justin Clifford, High School Student, Alpine, Utah
'There must be no barriers for freedom of inquiry. There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors.'