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What modulates our Sun? The majority of science work on the principle that the Sun is self modulating and each solar cycle is a product of a random number generator. There are others that suspect the Sun is modulated by the planets with a special emphasis on Uranus & Neptune. Thanks to Carl Smith who has recently left us we have new knowledge that significantly adds to Jose, Landscheidt & Charvàtovà's work.

Geoff Sharp

Will SC24 be the Shortest Cycle in the SSN Record?

The monthly average for July 2016 is 10.8 confirming the trajectory of the activity slide occurring over the past 30 months or so. If the trend continues SC24 will be judged overall as lower than the first cycle of the Dalton Minimum (SC5) occurring in the early 1800's along with one of the shortest cycles in the sunspot record (see SC5/SC24 comparison graph below). Many have predicted that if SC24 was to be a low cycle it would be of a longer duration (12-14 years), but as we might be witnessing SC24 will indeed be a lot shorter than the average 11 year cycle.

The AMP event or disordered solar orbit that occurred at SC5 was of a weaker nature than the AMP event during SC24, and  previous to that the only comparable AMP event was during the Maunder Minimum where records are weak. So SC24 is the first cycle to record modern data for a grand minimum type cycle, and we are seeing some unexpected results. Apart from the low activity and shorter cycle we also have a very weak solar northern hemisphere when measuring the solar pole magnetic strength, the divergence between the poles is the largest measured in the modern record of around 40 years and will probably result in a disturbed solar dynamo that should ensure a weak SC25 before recovering somewhat in SC26. Of note is that there are no following AMP events until 2150, so don't expect a Maunder type minimum this time around (the next Maunder type event is over 1000 years away).

SC20 at 11.7 years long is starting to look lengthy for SC24?

Stronger AMP events coincide with a larger movement away from the SSB (red cross hairs) in the early stages of the disordered inner loop orbit (green line). This phenomenon also coincides with almost all known larger solar downturns across the Holocene. McCracken et al show that all grand minima only occur during the AMP event or blue bars (No grand minima during the ordered phase when Uranus and Neptune are apart)

Many thanks go to Carl's brother Dave for providing the Domain, Server and Software.