I ran across this article and wondered what the experts thoughts were on this topic. I know we can barely predict Earth weather 5 days in advance with accuracy. I don't feel like it's click bait, but it also seems highly speculative. If this is a duplicate, please delete the thread.

https://www.livescience.com/space/the-sun/a-mysterious-100-year-solar-cycle-may-have-just-restarted-and-it-could-mean-decades-of-dangerous-space-weather

Agree, its not really click bait although they added the sensationalistic words "and it could mean decades of dangerous space weather" . Title would have been fine without that.

I'm no expert but I saw a similar article published elsewhere, both based on the March 2025 published paper https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024SW004238

What I found fascinating is the possibility (likelihood?) that there are many long term cycles the sun goes through. We know about the sunspot cycle as well as a few others but how many long period cycles does the sun experience that we don't know about yet. Since we've only been observing it in detail for a few hundred years. And that was just visually for a few hundred years. We still don't have a good grasp on the physics that drive the suns behaviors so I'm certain there are oscillations we will learn more about in time.

It will be interesting to see if any expert here weighs in on this.

On 4/22/2025 at 10:53 PM, Rainman_ said:

I ran across this article and wondered what the experts thoughts were on this topic. I know we can barely predict Earth weather 5 days in advance with accuracy. I don't feel like it's click bait, but it also seems highly speculative. If this is a duplicate, please delete the thread.

https://www.livescience.com/space/the-sun/a-mysterious-100-year-solar-cycle-may-have-just-restarted-and-it-could-mean-decades-of-dangerous-space-weather

On 4/22/2025 at 11:27 PM, astroHoward said:

Agree, its not really click bait although they added the sensationalistic words "and it could mean decades of dangerous space weather" . Title would have been fine without that.

I'm no expert but I saw a similar article published elsewhere, both based on the March 2025 published paper https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024SW004238

What I found fascinating is the possibility (likelihood?) that there are many long term cycles the sun goes through. We know about the sunspot cycle as well as a few others but how many long period cycles does the sun experience that we don't know about yet. Since we've only been observing it in detail for a few hundred years. And that was just visually for a few hundred years. We still don't have a good grasp on the physics that drive the suns behaviors so I'm certain there are oscillations we will learn more about in time.

It will be interesting to see if any expert here weighs in on this.

The biggest problem with that interpretation in my opinion is that the findings aren't really telling us anything new, just that the last several cycles have been seeing a steady decline, which has now turned around with SC25. That's all well and good, but the interpretation of this as the CGC (centennial Gleissberg cycle) remains just as speculative as before if you ask me. With activity as low as SC24 last cycle one might expect the turnaround of SC25 on purely statistical grounds through regression to the mean (in fact, if one had predicted SC25 to simply be a mean cycle that'd have been quite close to correct).

As a counterpoint to that most recent resurgence of CGC claims, there's e.g. this paper by Cameron & Schüssler which purports to show that all cycles longer than the 11-year one are fully consistent with noise, thus being unable to disprove the null hypothesis of no such cycles being inherent to the dynamo itself; summarized in the abstract:

Using this model as a null case, we show here that all local peaks with enhanced power, apart from the 11-year band, are consistent with realization noise. Even a 3σ peak is expected to occur with a probability of about 0.25 at least once among the 216 period bins resolved by the cosmogenic isotope data. This casts doubt upon interpretations of such peaks in terms of intrinsic periodicities of the solar dynamo process.

And their conclusion, with the typical scientific caveat that the results don't necessarily preclude such longer cycles being real, but also again noting that the observations being consistent with the null hypothesis means there's a lack of evidence for it at present:

Our analysis shows that the fluctuations in the power spectrum of the sunspot numbers reconstructed from cosmogenic isotopes are consistent with a weakly nonlinear and noisy limit cycle with no intrinsic periodicities except that of the basic 11/22-year cycle. Such a mode of operation of the solar dynamo is suggested by solar and stellar observations and can be faithfully described by a generic noisy normal form model with parameters taken from observations. Seemingly significant periodicities such as the ∼90-year Gleissberg and the ∼210-year de Vries “cycles” are expected to occur in random realizations as a result of the stochastic noise in the dynamo excitation. This conclusion is further strengthened by the sharpness of the corresponding peaks in the power spectrum, indicating a random origin.

Of course, our analysis cannot per se exclude that these periodicities may be intrinsic after all, but we have shown that, so far, this notion is not supported by the data, which are consistent with the NNF null case. The interpretation of such periodicities in terms of dynamo theory should therefore be considered with due caution.

Personally I'd love for it to be real, since it would mean several decades ahead with higher likelihood of more and more activity, but as they say one should be cautious and not jump to conclusions about it given the current state of evidence.

Edited April 24Apr 24 by Philalethes
typo