Comparison of sunspot periods with planetary synodic period resonances

Abstract

FOR decades, the closeness of the 11.1-yr cycle of solar activity and the 11.86-yr period of Jupiter has been noted, along with some speculation that the planets may have a causal effect on triggering solar activity. Two studies^1,2 have presented a planetary function which stays in phase for hundreds of years, and both of them considered the influence of the planets with large values of mass/(distance to Sun)³ or (m_i/d_i³), namely Jupiter, Venus, Earth, and Mercury, although Mercury effects were not evaluated quantitatively in either case because of the assumption that they would represent a short term perturbation. Okal and Anderson³ indicate that Mercury effects can be important and that the magnitude of the tides of the Sun do not have the same power spectrum as the solar activity. Although this paper does not consider Mercury, it presents a more general model than just a tidal concept; tides are likely to be less important than torque effects on the oblate spinning Sun, for example. The study reported in ref. 3 was limited to an evaluation of the maximum tidal potential. Lack of correlation of this function with solar activity is not equivalent to reducing the credibility of all planetary hypotheses of solar activity.