Index

Sunspot cycle forecast and planetary correlations
by Jan Benestad at www.sibet.org

Tidal forces and wobble

The Sun wobbles, when seen from outside the solar system.
If the Sun only had one planet, Jupiter in a circular orbit, the wobble would be constant.
But Saturn and the other planets make the wobble-rate more complex and changing all the time.

I think this changing wobble has some some kind of effect on the Sun, that results in sunspots.
Maybe the changing wobble deforms the sun, or affects the rotation or other effects.

I simplify my analysis and concentrate on the two major planets that affect the wobble: Jupiter and Saturn
What I find, is that stable wobble (around Jupiter-Saturn conjunctions/oppositions) results in low sunspot activity.
And changing wobble results in higher sunspot activity.
Maximum sunspot activity typically occurs after the maximum wobble-change (about 2 years lag). But the highest rate of change in sunspot activity correlates well with wobble change.

The synodic Jupiter-Saturn cycle is about 20 years, and 10 years between conjunctions and oppositions.
So the sunspot cycle should be about 10 years. But it isn´t... why?

-Because there is another important (perhaps even more important) effect - the tidal forces.

Simplyfied the tidal force from a planet is a m/r^3 effect, and the significant planets are Jupiter, Venus, Earth and Mercury  (in that order). And high tidal force means higher sunspot activity.
So there are two major mechanisms that affect sunspot activity. They may be separate, or perhaps the wobble and tidal forces are connected (high change in wobble makes higher tidal force?)

When examining the tidal forces for the solar system we find some important patterns:
-the Jupiter orbit is elliptical. So the tidal forces from Jupiter are highest when Jupiter is around it´s perihelion every ~12 years
-Venus and Earth have near circular orbits, but Mercury has an elliptic orbit. The strongest tidal effect from Mercury is at it´s perihelion, which is near 90 degrees from the Jupiter perihelion. The result is that Mercury has a dampening effect on the Jupiter tidal force just around the Jupiter perihelion (when the Jupiter force is highest). And also a dampening effect when Jupiter is at aphelion (lowest tidal force)
-the last but maybe most important pattern are the Venus+Earth+Jupiter syzygies, when all three planets are alligned (conjunct or opposed) when seen from the Sun. These syzygies are strongest every ~11 years (on average) and correlates with the average sunspot cycle length

So there are three major cycles of approx 10, 11 and 12 years that affect the sunspot cycle, and they all show up in the fourier spectrum of monthly sunspot-data.
There could be an unifying theory that incorperates these three cycles, but so far I analyze them separately.

In periods we can see that one of these cycles dominate, while the other(s) are less significant.
In periods of strong solar cycles it is typically the short 10 year cycle that dominate, and in periods of weak solar cycles it is the longer 12 year cycle that dominate.
When examining past solar cycles we can find some helpful and important patterns and supercycles.

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