A paper by Nicola Scafetta in the Journal of Atmospheric and Solar-Terrestrial Physics is bound to get alarmists in a tangle – see http://tallbloke.wordpress.com/2012/03/21/nicola-scafetta-major-new-pape… … the abstract of the online paper says the Schwabe frequency band of the Zurich sunspot numbers between 1749-2011 is found to contain three major cycles in periods of 9.98, 10.9 and 11.86 years. The frequencies appear to be closely related to the spring tidal periods of Jupiter and Saturn, and the tidal sidereal period of Jupiter. A simplified harmonic constituent model based on the above tidal frequencies and tidal phases of Jupiter and Saturn has a best position that varies at intervals of 115, 61, and 130 years plus a quasi-millennial cycle of around 983 years. These can be found in proxy climate records during the entire Holocene. The heartbeat oscillation pans out reasonably well with known prolonged periods of low solar activity during the last thousand years. The consensus view appears to be that there can be no planetary affect on the Sun because all the bodies in the solar system are in free fall together. However, evne in free fall they might have gravitational influences on each other. A commenter points out the Earth and its moon are in free fall yet the moon influences the ocean tides – due to resonance well in excess to what can be explained by gravity alone. The warmists have referred to Scafetta as a 'climate astrologer' – but this is because they wish to downplay the role of the Sun on the climate experienced on the surface of the Earth. If so, Scafetta was prceded by Rhodes Fairbridge and by Otto Pettereson (1914).
In another post at http://tallbloke.wordpress.com/2012/03/22/how-can-jupiter-and-saturn-aff… … quite how the planets may affect solar variability is explored. Was it by gravitation, tidal pull, or by electro-magnetism? In terms of tidal strength Jupiter has a greater effect than Saturn, while Venus, Earth and Mercury exhibit a greater force than Saturn too as they are much nearer to the Sun (see also http://tallbloke.wordpress.com/2012/03/23/the-sun-dances-the-soho-two-step/
Tall Bloke is inclined to the view that the timing of solar cycles is being modulated more strongly by electroc-magnetic forces rather than by tides or gravity – but not all the commenters agree with him (see also www.vukcevic.talktalk.net for the Parker spiral animationand see also http://en.wikipedia.org/wiki/File:Heliospheric-current-sheet.gif).