> "There is also annual precession wobble"

Geophysicists appear equally clueless about the origin of the Chandler wobble (CW), which is a simple applied torque of the lunar nodal cycle mixed with the annual cycle.


In the figure above, the main Chandler wobble frequency is indicated by the upward **GREEN** arrow in the CW power spectrum. The frequency of 0.843/year is predicted by the aliasing of an annual impulse with the fortnightly draconic/nodal lunar tidal cycle, providing a twice-annual sharp torquing (but variable due to aliasing) and thus sustaining the polar axis cyclic wobble. Consider also that if the southern node torque is equal to the northern node torque, then spectral peaks at 0.157/year and 1.843/year will *not* emerge in the calculated Fourier terms. Thus the symmetric-forcing model spectrum in **RED** does not reveal the additional satellite terms, even though these satellite terms do occur in the data, indicated by the pair of downward **GREEN** arrows pointing to peaks in the the **BLUE** curve.

This is not *proof* that the Chandler wobble is caused by mixed lunisolar forcing, but no other model will explain it as well, both plausibly and parsimoniously.