Nikola Tesla and the early idea of global resonances

Around 1899, in his laboratory in Colorado Springs, Nikola Tesla experimented with the transmission of energy and with what he described as global standing electromagnetic waves or "Earth resonances". In this sense he anticipated the very idea of global planetary resonances, namely that the Earth as a whole can exhibit resonant electromagnetic behavior.

It is necessary, however, to clearly distinguish historical anecdote from established science: Tesla's experiments were not the Schumann resonance in today's precise sense — that is, the resonances of the Earth-ionosphere cavity excited by lightning, as defined by Schumann (#9) and measured by Balser and Wagner (#12). Tesla worked with his own generators and with earth currents, not with a global resonator in today's understanding. His alleged frequency estimates are moreover historically uncertain and cannot be reliably identified with today's measured values (~7.83 Hz for the first mode).

Tesla's contribution here therefore belongs to the realm of historical context and inspiration, not among the experimental evidence for the Schumann resonance.