The Schumann Resonance which is constant at 7.83 Hz and is calculated from the time it takes for an electromagnetic signal to travel once around the earth, bouncing off the ionosphere as it goes....
The ideas that this frequency is shifting up to approx 13 Hz is very much a misnomer, perpetrated by the spiritual community in the best of intentions but not scientifically correct, I do have a foot in both camps so like to check up on what is being discussed.
There are harmonics of the Schumann Resonance which follow normal musical intervals of the octave, fifth, fourth and third which may be easily calculated. There is another frequency of 40 Hz which has been measured emanating from deep down in the earth's crust which is said to originate from a crystalline core but much is still speculation as we do not have the technology to prove it !
By Philip Sterling
http://www.astrosound.co.uk/
