Guest post by David Archibald
Long suspected, it seems that this has now been confirmed by a paper in Astronomy and Astrophysics with the title “Is there a planetary influence on solar activity?” by Abreu et al that was published on 22nd October, 2012.
From the Discussion and Conclusions section:
The excellent spectral agreement between the planetary tidal effects acting on the tachocline and the solar magnetic activity is
surprising, because until now the tidal coupling has been considered to be negligible. In Appendix A we show that the possibility of an accidental coincidence can be ruled out. We therefore suggest that a planetary modulation of the solar activity does take place on multidecadal to centennial time scales.
The authors note that current solar dynamo models are unable to explain the periodicities in solar activity such as the 88 year (Gleissberg), 104 year, 150 year, 208 year (de Vries), 506 year, 1000 year (Eddy) and 2200 year (Halstatt) cycles. They adopted a different view by regarding the planets and the solar dynamo as two weakly coupled non-linear systems.
The idea that planetary motions may influence solar activity seems to have been initiated by Rudolf Wolf in the 1850s. While energy considerations clearly show that the planets cannot be the direct cause of solar activity, they may perturb the solar dynamo.
Specifically, the authors calculated planetary torque at the tachocline. The tachocline of the sun is a shear layer which represents a sharp transition between two distinct rotational regimes: the differentially rotating convection zone and the almost rigidly rotating radiative interior. The tachocline plays a fundamental role in the generation and storage of the toroidal magnetic flux that eventually gives rise to solar active regions. A net tidal torque is exerted in a small region close to the tachocline due to the buoyancy frequency originating from the convection zone matching the tidal period. The tachocline is thought to be non-spherical – either prolate (watermelon-shaped) or oblate (pumpkin-shaped). The authors’ model describes planetary torques acting on a non-spherical solar tachocline.
Figure 5 from the paper shows the 10Be record, shown as modulation potential, and planetary torque in the frequency domain:
Panel a is the Fourier spectrum of the solar activity quantified by the solar modulation potential. Panel b is the Fourier spectrum of the annually averaged torque modulus. The spectra display significant peaks with very similar periodicities: The 88 year Gleissberg and the 208 year de Vries cycles are the most prominent, but periodicities around 104 years, 150 years, and 506 years are also seen.
The match between theory and the physical evidence is very, very good. As the authors put it,”there is highly statistically significant evidence for a causal relationship between the power spectra of the planetary torque on the Sun and the observed magnetic activity at the solar surface as derived from cosmogenic radionuclides.”
They also advance a plausible mechanism which is that the tachocline, playing a key role in the solar dynamo process, is a layer of strong shear which coincides more or less with the layer of overshooting convection at the bottom of the convection zone. The overshoot layer is thought to be crucial for the storage and amplification of the magnetic flux tubes that eventually erupt at the solar photosphere to form active regions. Small variations in the stratification of the overshoot zone “of about -10-4 may decide whether a flux tube becomes unstable at 2·10-4 G or at 10-5 G. This makes a great difference, because flux tubes that do not reach a strength close to 10-5 G before entering the convection zone cannot reach the solar surface as a coherent structure and therefore cannot form sunspots.” This sounds like an explanation for the Livingstone and Penn effect of fading sunspots.
Figure A.1 from the paper also shows the very good correlation between cosmogenic radionuclides from the period 300-9400 years BP and the model output:
Upper middle panel: 14C production rate derived from the INTCAL09 record
Lower middle panel: solar modulation record based on 10Be records from GRIP
(Greenland) and Dronning Maud Land (Antarctica) and the 14C production rate
Bottom panel: Calculated torque based on planetary positions
If planetary torque modulates solar activity, does solar activity in turn modulate the earth’s climate? Let’s have a look at what the 10Be record is telling us. This is the Dye 3 record from Greenland:
All the cold periods of the last six hundred years are associated with spikes in 10Be and thus low solar activity. What is also telling is that the break-over to the Modern Warm Period is associated with much lower radionuclide levels. There is a solar mechanism that explains the warming of the 20th Century. It is also seen in the Central England Temperature record as shown in the following figure:
Conclusion
This paper is a major advance in our understanding of how solar activity is modulated and in turn its effect on the earth’s climate. It can be expected that planetary torque will progress to being useful as a tool for climate prediction – for several hundred years ahead.
Reference
J.A. Abreu, J. Beer, A. Ferriz-Mas, K.G. McCracken, and F. Steinhilber, Is there a planetary influence on solar activity?” Astronomy and Astrophysics, October 22, 2012
Thanks to Geoff Sharp, the full paper can be downloaded from here.
(Note: This post was edited for title, form, and some content by Anthony Watts prior to publishing)
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Ah, good explanatory post by Leif has appeared :
http://wattsupwiththat.com/2012/11/11/solar-activity-past-present-future/#more-74152
This is quite funny. several years ago, before he died, I had a wonderful email exchange with James P Hogan over climate change hysteria, and the idea that there would be a link found between the Earth and the Sun (in that causal direction) and that the alarmists would then claim that it’s not that the Sun causes changes in the Earth’s climate having nothing to do with CO2 concentration, but that it’s the CO2 here causing the Sun’s output to increase, causing warming.
It was meant to be snark …
Leif Svalgaard says: November 11, 2012 at 3:09 pm
“….The barycenter has no tidal effect as it has no mass….The tidal effects come from distant planets….”
Surely the relative position of the barycenter is entirely dependent upon the positions of the planets relative to the sun.
So there could quite conceivably be additive and cyclical tidal effects which could be directly related to barycenter cycles and positions.
P. Solar says:
November 12, 2012 at 2:59 am
Ah, good explanatory post by Leif has appeared :
yes, if you read it carefully, his plans to manipulate and homogenise the datasets to his preferred flatness are quite clear.
Tidal forces are always present, but the deviations from free fall are extremely small. The argument is not about tides, but about exchange of angular momentum [other than through tides]. The barycenter has no tidal effect as it has no mass. The tidal effects come from distant planets.
in it. The Sun has an radius that is on the order of 0.01-1% the orbital radius of the planets from Saturn on in — from the Sun’s point of view these planets are not all that “distant” (about the ratio of my size to the size of a football field to the nearer planets, a few times that to Jupiter and Saturn). The ratio of the Earth’s radius to an AU is rather small, yet the effect of solar tide is easily discernible — the ratio of the Sun’s radius to that orbit is many orders of magnitude larger, and the tidal force differential of the Earth on the Sun is hence those many orders of magnitude larger, cubed. Jupiter is 300 times more massive that the Earth, 5 times more distant, base gravitational force on the Sun around twelve or thirteen times as great — and then again, one can start to trade off the cubic term.
The first is not entirely clear to me without doing the computations, largely because the sun is so — well, large. Tides are funny — the Earth is much larger than the Moon but the Lunar tidal “force” (differential) on the Earth is much larger than that of the Earthal tidal force on the Moon, because it scales like the same basic term but with
I’m certain that these forces are small relative to Solar gravity, but they are not exactly small in absolute terms and the Sun is a fluid body capable of sustaining driven tidal waves. The tidal force on Earth is also small compared to the absolute gravitational force on its surface, so small that one can hardly measure it with direct instrumentation, yet it does just fine at driving an easily observed surface wave even in a medium with considerable damping. Hence my wish to see computations, not claims made either way that aren’t backed up by actual arithmetic done by somebody that is trying to see whether or not they are true. I don’t think one can just say “this is small, therefore we can ignore it” in this context, just as I don’t think one can say “this exists and isn’t zero, therefore it is a proximate cause of… (fill in the blank). Is this so unreasonable? So references that show the results of magnetohydrodynamic simulations including tidal effects would be greatly appreciated — either way.
But what bothers me in this reply is the following statement: “The argument is not about tides, but about exchange of angular momentum [other than through tides].”
It was my understanding that the process that exchanges orbital angular momentum between planets, and between planets and the sun, between the earth and the moon, is the torque caused by the tidal bulge lagging the direct line connecting the centers of the orbiting, rotating objects. There is a nice picture, along with a very simple version of the argument (sadly without the not terribly difficult computation of the force difference in a binomial expansion) here:
http://www.themcdonalds.net/richard/astro/papers/602-tides-web.pdf
that shows how tidal forces exerted on rotating fluids exert torques, torques that long ago tidally locked the moon (and is still exchanging angular momentum with the Earth today as the Earth’s rotation slows and the Moon’s orbit rises).
So what other interactions enable the exchange of angular momentum? Not the direct gravitational force, surely, as it exerts no torque. Is there some other force of which I am not aware?
Question for Leif?
Are these correlations rigged or coincidence?
If they are real, meaning they point to something causative, what is the explanation?
rgbatduke says:
November 12, 2012 at 6:25 am
Hence my wish to see computations,
Slides 21 and 4 of http://www.leif.org/research/AGU%20Fall%202011%20SH34B-08.pdf
So what other interactions enable the exchange of angular momentum? Not the direct gravitational force, surely, as it exerts no torque. Is there some other force of which I am not aware?
There are no other forces, but the proponents of the ‘Angular Momentum’ planetary ‘theory’ claim that there is a mysterious ‘spin-orbit coupling’ that exchanges angular momentum between the Sun and the Planets.
James Cross says:
November 12, 2012 at 6:46 am
Are these correlations rigged or coincidence?
I think they are coincidences and need no ‘explanation’.
Leif Svalgaard says:
“There are no other forces, but the proponents of the ‘Angular Momentum’ planetary ‘theory’ claim that there is a mysterious ‘spin-orbit coupling’ that exchanges angular momentum between the Sun and the Planets.”
Not familiar with the “angular momentum” planetary theory, but if one forgets for a moment about defining gravitational “forces” and the long distance depletion of the effects of those forces, but thinks instead in terms of general relativity and the curvature of space/time around the mass of the sun and each of the planets, and that all are traveling in straight lines through curved space while curving the space around themselves relative to their mass, long distance interactions seem decidedly more feasible. Those long distance curvatures are enough to keep Jupiter in its orbit and Jupiter’s influence to change the shape of the Earth’s orbit around the sun in a fairly predictable way per the Milankovich cycles. The more mass, the more that space is curved and the slower that times passes relative to other frames of reference. Gravity as a fundamental “force” may well be misnamed and the search for the “graviton” a fools errand for , it is geometry that is fundamental in gravity, as you said, that is of course, if one buys general relativity.
Jim G says:
November 12, 2012 at 10:47 am
Not familiar with the “angular momentum” planetary theory
Not that it is coherently explained, but this seems to be the gist of it:
http://www.landscheidt.info/?q=node/5
it is geometry that is fundamental in gravity, as you said, that is of course, if one buys general relativity
GR has passed every test it has been put to, so that is easy.
Slides 21 and 4 of http://www.leif.org/research/AGU%20Fall%202011%20SH34B-08.pdf
So what other interactions enable the exchange of angular momentum? Not the direct gravitational force, surely, as it exerts no torque. Is there some other force of which I am not aware?
There are no other forces, but the proponents of the ‘Angular Momentum’ planetary ‘theory’ claim that there is a mysterious ‘spin-orbit coupling’ that exchanges angular momentum between the Sun and the Planets.
Thank you, the former was indeed very instructive, and the latter explains a lot as well. In particular I was struck by the differences between your FTs and the FTs in the top article above (both sets). Yours actually look a lot more reasonable (although enquiring minds still want to know the length of the interval being transformed in order to know how seriously to take the long period peaks).
In addition I agree with your conclusion almost exactly (and agreed with them from the beginning, even without this summary. It seems unlikely that the torque/tide explanations are correct, moderate coincidence the data notwithstanding. There are moderate coincidences in tidal data for the Earth and inflation rates, after all:-). That doesn’t mean that these explanations are wrong, only that there is a strong burden of proof on those that advance them to quantitatively explain them and show that computations based on they hypothesis have good predictive value.
This leaves them with some hope, some lines of attack, but with some serious work to do beyondI’m not sure that there isn’t a way of deriving the so-called barycentric effect, or torque in a set of reduced variables, that works out to be a modified collective tidal force that varies more strongly than the two body torques. But then, I’m not willing to take the time to try to derive them myself, and surely working out the detailed physics of this would be the very first step of somebody advancing this sort of hypothesis.
A few other comments on places that might leave room for some effect (or at least might patch up some of the objections).
a) A lot of the Sun’s internal motion is nonlinear and chaotic. Phenomena such as the phase inversion “catastrophe” visible in the data aren’t all that unexpected in a chaotic system with multiple locally stable attractors, and in as complex a system as the solar system and solar interior collectively are, complexity in this space could also explain why Wolf’s semi-heuristic fit/explanation works decently locally but not globally. All it takes is other dynamics introducing phase drift, nonlinearities, non-random noise, in a causal space of sufficiently high dimensionality, and what we see is no longer a neat fourier sum of perfectly periodic orbital influences but something much more complex where those influences are only a source of signal that can be nonlinearly amplified — or not — depending on details of the state of the rest of the system.
b) Along the same lines, the Earth’s tides are hardly uniform — the neat parameter “T” that you introduce as the “tidal bulge” (I’m assuming the deviation of the equipotential from spherical at the surface) is amplified many times on Earth by continental structures and resonances in some places, and are much smaller in others. It is certainly not the case that the Great Lakes (for example) go up and down by a quarter of a meter (lunar and solar combined) — a millimeter might be more like it– where in the Bay of Fundy tides are routinely 5 meters. The bulge in the lithosphere, on the other hand, is of this order.
The bulge in the atmosphere, on the third (gripping) hand, is orders of magnitude larger than the tides in the Bay of Fundy. These bulges cause fluctuations in the surface atmospheric pressure of order of 0.01% (100 microbars) making them difficult to resolve from weather “noise”. Solar atmospheric tides are a perfect example of how two effects with similar periodicities can heterodyne, as they are much larger than lunar tides even though the solar tidal force is much smaller. They combine with the similarly driven cycle of heating and thermal expansion and cooling, to greatly increase the size of the solar bulge through resonance.
Note well that solar and lunar atmospheric tides are actually rather huge compared to T from your formula, because even a small change in the gravitational field causes expansion over a very long distance and has a long ways to add up in a gaseous (compressible) fluid. Even for a relatively incompressible fluid with a surface, the standing waves can grow well beyond T if there is any “structure” to channel the surface waves.
How does all of this apply to the Sun? I don’t know. I’m guessing that the convective zone is the place where the Sun stops being “incompressible” and approximately rigid, so that tidal bulges at the thermocline itself would be very small unless they encountered some sort of positive feedback, a resonance with some other process (e.g. core fusion rates that are slightly modulated by pressure, producing chuffing, with the possibility of favorably driving chuffing frequencies that match tidal frequencies). Up above that, however, they could be a lot more like atmospheric bulge — even a small expansion per meter has a lot of meters to add up in as one rises through half a million meters, and I can thereby imagine a much more substantial tidal bulge than 2 mm in the upper reaches of the Sun.
This leaves me back at the beginning — the top article is suggestive, but hardly (as it claims) conclusive, with a lot of work to be done. Your talk/article strongly reinforces the latter (and nibbles at the former). The real question is: Given that all of the work you outline in your survey has been done, why didn’t the article work through it and provide a concrete model that — perhaps — answers some of the well-known objections? Until this is done, I have to continue to doubt it, just as I similar continue to doubt similar results based on Fourier/Wolf analysis. Suggestive yes (since the time of Wolf, yet). Predictive? Not so much. Explanatory? Not without filling in a lot of missing pieces quantitatively, not with “and then a miracle happens and it is the cause anyway” where data does not fit. Even if a miracle DOES happen (due e.g. to chaos and strange attractors) one needs to show SOME chaotic model that exhibits at least SOME behavior like that observed, surely.
So again, thank you very much, Lief, for patiently attending to my education in this.
rgb
Tallbloke, you admit saying…
“There are those of US…….”
then you write…..
“I didn’t say I was one of them.”
Definition of “us”….
” Used by a speaker to refer to himself or herself and one or more other people.”
What is Leif supposed to think?
Some facts. The Abreu et alia paper was submitted to AA on 12 July, 2012. As Mike Jonas says, it was accepted by AA on 24 September 2012. The proofs were corrected on or about 6 November 2012. A perfectly normal process. The 17Mai 2011 (TWICE- in French) ) was clealy a misprint, which was corrected in the proof stage.
rgbatduke says:
November 12, 2012 at 12:08 pm
Thank you, the former was indeed very instructive, and the latter explains a lot as well.
Just some more on the solar atmosphere:
1) Gravity is 27 times stronger than in the Earth’s atmosphere
2) The temperature of the Sun in ‘quiet’ areas [away from sunspots and other strong magnetic fields] is very constant. Livingston has measured the temperature using temperature-sensitive spectral lines over almost 40 years and finds no variation at all [not even with the solar cycle] larger than about 3 degrees [out of 6000]: http://www.leif.org/EOS/2005ASPC-Livingston-Temp.pdf
feral physicist says:
November 12, 2012 at 12:22 pm
Some facts. The Abreu et alia paper was submitted to AA on 12 July, 2012. As Mike Jonas says, it was accepted by AA on 24 September 2012.
Sounds more reasonable, but sort of does put this to shame:
tallbloke says:
November 10, 2012 at 11:46 am
“It might have been accepted in May 2011 on submission, but it wasn’t published until October 2012. Plenty of time for peer review and suggested alterations and various to-ing and fro-ing. Those of us who have been aware of the progress of this paper throughout that time know how rigorously it has been vetted prior to publication”
it is geometry that is fundamental in gravity, as you said, that is of course, if one buys general relativity
“GR has passed every test it has been put to, so that is easy.”
So, considering the difference between thinking of gravity as simply a force which diminishes rapidly with the square of the distance visa vi a geometric consequence of the presence of mass, which also affects time, does this not open up other possibilities for the degree of long distance influence interacting gavity “wells” might have upon a variety of factors both solar and planetary?
rgbatduke says: November 12, 2012 at 6:25 am
“…. Hence my wish to see computations…”
rgbatduke: All of this is well above my pay-grade but the following may be relevant:
I. R. G. Wilson, B. D. Carter, I. A. Waite; Does a Spin-Orbit Coupling Between the Sun and the Jovian Planets Govern the Solar Cycle, Publications of the Astronomical Society of Australia, 2008. http://www.publish.csiro.au/?act=view_file&file_id=AS06018.pdf
All from : Extra Terrestial Influences on Nature’s Risks. Brent Walker 2012 http://www.actuaries.org/HongKong2012/Papers/WBR9_Walker.pdf
Jim G says:
November 12, 2012 at 1:53 pm
does this not open up other possibilities for the degree of long distance influence interacting gravity “wells” might have upon a variety of factors both solar and planetary?
If you have some specific possibility in mind and can quantify it, then it can be tested. Otherwise it is just wishful thinking.
Leif Svalgaard wrote:
As usual, the discussion has degraded to the pushing of personal pet theories and assorted nonsense and misunderstandings and the original topic is largely forgotten.
Indeed. The original topic, it seems to me at least, is the title question “Is there a planetary influence on solar activity?”
I find it interesting that the claimed correlation in the paper isn’t greatly disputed here. It is seen either as an indicator of causation or as a complete coincidence, but not dismissed as non-existent. Since the supposed correlation is the reason this particular planetary influence theory exists at all, that seems the first place to look.
Is the correlation real, as in specific to events and persistent with time? Or is it selectively imagined or even cynically fabricated as in astrology?
If it is real, can this correlation (not some other) also be easily shown to be specific to events and persistent with time in some unrelated arena, such as the frequency of the occurrence of the letter L in a Shakespeare play (the more absurdly disconnected the better). If a similar match can be shown then this correlation based planetary influence theory can be reasonably said to be baseless.
If the correlation is real and stubbornly unique to this apparent relationship, then it will remain an interesting little elephant in the room for the solar physicists to stub their toes on as they explore the dark looking for the light.
By the way, today’s Bing image (UK page anyway) is superb and strangely topical. Just at the epoch where, on the Moon’s steady tidal driven ride away from the Earth it happens to appear, on average, the same size as the Sun, a species suddenly evolves that happens to find such a correlation rather cool. What a coincidence!
Some nifty solar physics on display. And is that Jupiter just off to the right? 😉
Abreu et al wrote:
Figure 5 from the paper shows the 10Be record, shown as modulation potential, and planetary torque in the frequency domain:
…
Panel a is the Fourier spectrum of the solar activity quantified by the solar modulation potential. Panel b is the Fourier spectrum of the annually averaged torque modulus. The spectra display significant peaks with very similar periodicities: The 88 year Gleissberg and the 208 year de Vries cycles are the most prominent, but periodicities around 104 years, 150 years, and 506 years are also seen.
I have a fairly normal human ability to see imaginary patterns in randomness (face on mars, etc) but I have to say I’m struggling with Figure 5. Take away the grey bars pointing out particular matches, and I see mostly mismatches. The grey bars supposedly indicate known periodicities in solar activitiy, but there isn’t much evidence in the 10Be graph of repeat peaks on the multiples.
Hmmm… is this – statistics?
PJF says:
November 12, 2012 at 7:16 pm
I have a fairly normal human ability to see imaginary patterns in randomness (face on mars, etc) but I have to say I’m struggling with Figure 5. Take away the grey bars pointing out particular matches, and I see mostly mismatches.
I compared Figures 1 and 4 and find peaks that come and go: http://www.leif.org/research/Abreu-Wavelet-Comparison.png sometimes in the ‘right’ places, sometimes not.
Maybe Leif you can imagine a pattern here.
And does that trend line (representing the rate of change) appear to be rising, or is it just my imagination that it is falling?
NaturalCyclist says:
November 12, 2012 at 9:45 pm
And does that trend line (representing the rate of change) appear to be rising, or is it just my imagination that it is falling?
Trend lines have error bars or uncertainties, so you have to plot those too, in order to assess the change.
The authors start this paper – promisingly – by stating that: “We adopt a di erent view by regarding the planets and the solar dynamo as two weakly coupled non–linear systems. In this paper we suggest that this coupling is not negligible and show that this hypothesis is able to explain the observed long–term cycles of solar activity.”
However there does not appear to be a real grasp of what is meant by a weakly forced nonlinear oscillator. A good example of a paper that studies a weakly forced nonlinear oscillator is here:
http://wwwold.nioz.nl/public/fys/staff/leo_maas/publications/dkm.pdf
Doelman et al take the case of a bay connected to the sea by a narrow inlet, and analyse the tidal movements within the bay as the consequence of tidal forcing from both solar and lunar tidal components. It turns out to operate as a nonlinear weakly forced oscillator with a complex set of forcing frequencies. To quote:
“The external forcing term ζext (t) is not an exactly periodic function of time. The tide at sea consists of lunar and solar components, and may contain annual, diurnal, semi-diurnal and, as a result of nonlinearity, all kinds of harmonic combination frequencies.”
Thus the system is a reasonable analogy of earths climate under a range of Milankovich and other astrophysical forcings, in terms of nonlinear system dynamics. The analysis involves the derivation of a Melnikov function, and – as can be seen by quickly looking through the paper – it involves some quite heavy-duty maths. In fact six alternative Melnikov functions are derived.
This is the kind of analysis required in the Abrieu et al paper. It is not enough just to mention the term “weakly forced nonlinear” and then in the rest of the paper just carry our wiggle-matching in a purely linear manner.
The authors conclude:
Finally, we note that the approach developed in this paper, and in particular the construction and evaluation of the mixed Melnikov function, can also be used to study general nonlinear oscillators with similar ‘almost resonant’ quasi-periodic forcing terms (see also [15,26,27]). In the case of small amplitude oscillations, the only ‘essential information’ on the oscillator is T2, the leading order quantity that describes the nonlinear character of the period of the periodic orbits of the nonlinear oscillator near the center point (2.8). This quantity can, of course, be determined for any nonlinear oscillator.
Leif Svalgaard says:
“If you have some specific possibility in mind and can quantify it, then it can be tested. Otherwise it is just wishful thinking.”
No, just trying to activate your creative thinking in the event you might have an outside the box idea on this. I’m just an old engineer who likes to question any type of dogmatic thinking. Seems to me there are already more than a few theories of long distance gravitational interaction out there however they treat gravity more as just another force than the geometric space/time situation descibed in GR.
Sometimes a picture is worth a thousand words. Does anyone get what’s going on in this one, which more clearly shows how the 3 prong cycle is the controller of grand minima? and that FFT type analysis misses the detail?
http://tinyurl.com/2dg9u22/images/trident.png