[hellbender]

The orbital period of Jupiter is about 11.9 Earth years, which is rather close to the average duration of a sunspot cycle (or half-cycle, as the complete cycle is about 22 years).

There is geological evidence that the sunspot cycle has maintained about the same duration for many millions of years, so the mechanism controlling or forcing it must be of great antiquity and continuity. The gravitational effect of planetary motions, esp that of Jupiter (more massive than all the other planets put together), would be a good suspect.

[SunkenCiv]

There is geological evidence that the sunspot cycle has maintained about the same duration for many millions of years

Wow, what geological evidence would that be, tell me, I must know. :')