Just as we harness energy from photons, we may also be able to harness other particles.
If we find the right materials and means of harnessing waves passing through earth, would could channel them just like aligning molecules in fluorescent tubes near power lines.
This experiment sounds more like capturing energy than generating it.
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...and as we know, energy is neither created nor destroyed. It is only transmitted or transformed.
In other words, in theory, if you are taking energy generated by the earths rotation, and if you do it in large enough amounts, over time you will slow the earth’s rotation.
I say in theory, because it would be impossible to be able to take enough energy to make a measurable change, even given a very extended time period.
I’ve touched a car that was on a road under power lines like this, and I got a small shock.