Scientists at the Princeton University, USA reported production of 17 microvolts of electricity from Earth’s rotation in an experiment published in Physical Review Research pushing the boundaries of science to solve Earth’s green energy demand with Earth itself. The scientists designed a foot-long device made from manganese-zinc ferrite and conducted experiments in a dark, windowless laboratory that remained stationary while the rotation of the Earth carried the cylinder through the magnetic field and produced 17 microvolts of electricity. Several experts viewed the results with scepticism as it violates the basic principle that any conductor at rest with respect to Earth’s surface cannot generate power from its magnetic field. They argued that any net voltage would be cancelled by the rearrangement of electrons during generation process itself.
Let us understand the process in simple language. Earth’s magnetic field is created due to the rotating liquid outer core at a depth of about 2900 km where the molten iron and nickel are in a constant state of turbulent convection due to radioactive heating and chemical differentiation. The movement of liquid metal creates electrical currents, which in turn create the earth’s magnetic field in a process called geodynamo that sustain the Earth’s magnetic field over geologic timescales. To generate electricity, two essential conditions should be met: i) a moving part such as a magnet and ii) a stationary part say a coil or a conductor. But that is not the case with Earth as it is rotating along with the Earth’s magnetic field. So, if we were to have a device that will remain stationary for longer periods of time under the spinning Earth, then it has to be above the Earth’s atmosphere. In this case there is another problem as the distance from the Earth’s surface increases the magnetic field becomes weaker. Contrary to the popular belief Earth’s magnetic field is very weak and its strength at the surface is roughly 25 to 65 micro teslas or 0.25 to 0.65 gauss which is at least 40,000 times weaker than a small bar magnet with strength around 10,000 micro teslas or 100 gauss. So, the question is would it work? Probably yes, as done in certain satellites with electrodynamic tethers that drag a wire through the magnetic field to generate electricity. But then, a genuine question would be, what would you do with that generated electricity that is far away from Earth?
In my opinion, 17 microvolts is a minuscule amount of electricity that need to be established beyond doubt as many other sources can cause small voltage discrepancies. The conclusions drawn need to be established by other independent studies to see the reproducibility of the results and the practicality of the idea. Science always gives wings to the mind and scientists always think aloud. So, if humans are planning to colonise other planets in future, sky is the limit for science to grow beyond the impossible. It is often said; Science is not given for nothing – science is taken with difficulty.
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