I quoted from a similar question on solar minima and maxima. "...I guess the jury is still out, but this is quite "fringe" material. The solar cycle is certainly thought to be a product of the dynamo mechanism that produces the magnetic field." So has something changed in the dynamo mechanism?

  • $\begingroup$ No, the variability has always been variable. Think of e.g. the Maunder minimum. $\endgroup$ Commented Jun 2, 2021 at 7:05
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    $\begingroup$ Where did you find this question? Please link it by editing the question. $\endgroup$
    – WarpPrime
    Commented Jun 2, 2021 at 12:37

1 Answer 1


The solar cycle is no less predictable than it has ever been.

The sun shows a roughly 11 year cycle of activity, but the activity and length in each cycle is also variable and shows trends, but no apparent periodicty

enter image description here
CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=969067

The graph shows 400 years of solar activity. The 11 year cycle is clear, and you can also see some trends in the longer term. The longer term trends don't follow a simple pattern.

So the pattern of solar activity is just as predictable or unpredictable as it has ever been. There is a cycle of 11 years, but what is less clear from the graph is that the some of these cycles are a little longer and some are a little shorter than 11 years. There are longer-term trends that are non-periodic. The causes of the cycle are the periodic relaxations and reversals of the sun's magnetic field. The causes of the longer-term variations are not well understood, and consequently not easy to predict.

There is some evidence of longer-term patterns that are indirectly observable in, for example, variations in the production of Carbon 14 in the atmosphere. There are proposals for periodicities of 210, 2400 and 6000 years.

We can say, with reasonable confidence that the next solar maximum will be in 2025. We expect that the intensity will be similar to the last peak with sunspot numbers at about 100 (based mainly on the observation that there isn't very large swings between one peak and the next). But it could reasonably be between 50 and 150. We would expect there to be peaks in 2036 and 2047, but we have little confidence in how active these future peaks might be, and we are not that confident in the timing.

The cause must be "something in the dynamo mechanism", but such variation is normal for our sun, it seems.

  • $\begingroup$ Apparently some cyclic behaviour of solar activity has been linked with our climate. Piers Corbyn has been quite successful with his predictions using current and past solar & lunar extreme events. weatheraction.com I am not in the least bit impressed by the 'dynamo mechanism' idea'. I think that is a mechanistic cop- out to avoid any external input. The Sun is in a constantly moving arm of the ISM and open to multiple external influences. I wonder what research has aimed at those long range cycles? $\endgroup$ Commented Jun 4, 2021 at 16:42
  • $\begingroup$ Nice idea, but doesn't work news.bbc.co.uk/1/hi/uk/6290228.stm $\endgroup$
    – James K
    Commented Jun 4, 2021 at 16:47
  • $\begingroup$ The BBC article concentrates on cosmic rays and fails to include any other mechanism. Here is a long list of other variables to consider: notrickszone.com/2013/10/11/…. We must not forget there are plasma electrical links to the Sun, the solar wind being but one of them. Plasma tends to form vorteces and our weather systems are largely built on vorteces and the Jet Stream. $\endgroup$ Commented Jun 6, 2021 at 9:23
  • $\begingroup$ I suspect you are verging towards the "Electric Universe" That way madness lies. It is a pseudoscience wilderland, populated by cranks, fraudsters and those that they have deceived. $\endgroup$
    – James K
    Commented Jun 6, 2021 at 9:31
  • $\begingroup$ Doesn't sound as though you have any respect for those who have a non-standard opinion about Cosmology. I label your kindred as LBOs the Left Brain Only brigade who had the Right, wide view brain removed at University. That unfortunately is the result of intensive mathematical training (brain washing) it teaches the concentrated narrow thinking, which is so typical of many astronomers and the like. It gets you a job but loses you the holistic view of the universe that we need. $\endgroup$ Commented Jun 7, 2021 at 12:27

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