The barycentre strikes back

Those who lament the timely closure of Pattern Recognition in Physics should lament no more: while the sun orbits the barycentre, papers that argue that this affects solar variability will get published. As evidence for this conjecture, I offer you McCracken et al (2014) and its precursor Abreu et al (2012).

Both papers discuss spectral peaks in a 9400-year record of solar activity reconstructed from the cosmogenic isotopes 14C and 10Be, from tree rings and ice cores respectively (high concentrations of the cosmogenic isotopes indicates a high flux of cosmic radiation and an inactive sun), and relate these spectral peaks to the influence of planets on the sun. Rather than invoking the “vanishingly small” planet-induced tides on the sun, both papers invoke the torque that the planets’ gravity imposes on the solar tachocline, the non-spherical layer that separates the inner and outer parts of the sun. The mechanism by which the very small torque forcing could be amplified into the reconstructed solar variability is left unspecified.

Figure 5 of Abreu et al shows the spectra of solar activity and their calculations of torque over the Holocene. Five of the peaks in the two spectra coincide. It’s looking promising. Nature certainly thought so.

Abreu et al figure 5. Comparison of solar activity and planetary torque in the frequency domain.  The spectra display significant peaks with very similar periodicities: the 88 yr Gleissberg and the 208 yr de Vries cycles are the most prominent, but periodicities around 104 yr, 150 yr, and 506 yr are also seen.

Abreu et al figure 5. Comparison of solar activity and planetary torque in the frequency domain.
The spectra display significant peaks with very similar periodicities: the 88 yr Gleissberg and the 208 yr de Vries cycles are the most prominent, but periodicities around 104 yr, 150 yr, and 506 yr are also seen.

Alas, there is problem. As Poluianov & Usoskin (2014) demonstrate, the data processing of Abreu et al will cause spurious spectral peaks in their torque spectrum. Abreu et al calculate the torque on a daily basis, but perform the spectral analysis on annually averaged data. This will cause aliasing of the sub-annual torque frequencies of Mercury and Venus, making them appear as low frequency spectral peaks. Poluianov & Usoskin (2014) repeat the analyses of Abreu et al, but using daily rather than annually averaged torque.

The planetary torque spectra computed here for the three sampling frequencies: 1, 10, and 365.24 year−1 for panels A – C, respectively.

Poluianov & Usoskin (2014) figure 3 Planetary torque spectra computed for three sampling frequencies: 1, 10, and 365.24 year−1 for panels A – C, respectively. Note how the spectral peaks change.

None of the spectral peaks found by Abreu et al remain – they are all aliasing artefact. The correct peaks don’t align with the peaks in the solar variability record. The aliasing problem should have demolished Abreu et al (Poluianov & Usoskin also argue the test for coherence between the torque and the solar record is too liberal), but in their response, Abreu et al (2014) basically declare that “tis but a scratch”. They admit that they have an aliasing problem, get confused about the effect of a constant term in their equation for calculating torque, and other things. Some how, the frequencies they originally found are still present, but as minor spectral peaks. It would be most curious for the sun to ignore major peaks in torque but respond to minor peaks.

Abreu et al maintain that using a Monte Carlo procedure, the odds of having the five peaks coincide is “is lower than 10−4“. They estimate this by counting the number of time the five spectral peaks are found in white or red noise processes, and from these calculate the probability of the five spectral peaks co-occurring. There are at least two problems with this, firstly the torque spectrum does not resemble red or white noise and second there are not just five spectral peaks in the solar reconstruction – there are at least eight. The relevant test is not finding the five peaks selected by Abreu et al in random data, but in finding any five out of eight peaks. There are 56 ways to do this – Abreu et al’s estimate of the odds is at least 56 times too low.

McCracken et al (2014) is a review of the evidence for planetary influences on solar activity. The three authors, who were all part of the Abreu et al team, declare

Despite our initial view that we would be able to prove beyond all reasonable doubt that no such correlation exists, it became clear that the contrary is true.

Six lines of evidence persuaded McCracken et al.

1) Four of the most prominent spectral peaks in the solar activity record approximate integer multiples of half the Neptune-Uranus synodic period of 171.42.

This looks like numerology to me.

It stretches credibility to believe that any physical mechanism links the Neptune-Uranus synodic period to one frequency in solar activity let alone four, especially given that Neptune and Uranus are much smaller and more distant than Jupiter. Yet McCracken et al write

The probability of these correlations occurring by chance is shown to be <10−4

This is, at the very least, a sloppy way to express the results of their Monte Carlo procedure, and is an example of the Texan sharpshooter fallacy. Given the eight planets, the number of orbital times and synodic periods is large, so it is really not that surprising that the solar spectral peaks are an integer multiple of one of these multiplied by a arbitrary fraction.

2) The frequencies in the solar proxy record match those in the torque applied by the planets to the solar tachocline, citing Abreu et al. These peaks in the torque spectrum are the ones that Poluianov & Usoskin demonstrated were spurious, arising from inappropriate data processing. McCracken et al neglect to cite Poluianov & Usoskin. They cannot claim not to have been aware of the work as together with Abreu they submitted their reply to Poluianov & Usoskin’s comment before McCracken et al was accepted. This does not look good.

Because torque diminishes with the cube of distance this second argument of McCracken et al contradicts the first as Neptune and Uranus are so remote from the Sun they apply very little torque compared with Jupiter and Venus.

3) The ~2300-year Hallstatt cycle in the solar activity data proxy approximates the half the period between the syzygy (alignment) of the four gas giants at 5272 BP and at 644 BP. Not the strongest of arguments: one peak of unknown statistical significance in the solar activity spectrum can be related to a transient planetary alignment of with no obvious mechanism for affecting the sun.

4) There is no new evidence at number 4. The argument is simply to state that if you multiple the miscalculated probability of argument 1 by that of argument 3 you get a very small and irrelevant number. That’s not quite how McCracken et al phrase it.

5) The barycentre, the centre of mass of the solar system about which the sun orbits, sometimes in a ordered pattern, sometimes in a disordered pattern depending on the alignment of the gas giants. These different modes of free fall, which comprise the Jose cycle, are compared with the solar activity spectrum to find patterns. Mechanisms are not so obvious.

  • Over the last thousand years, four of the seven periods with disordered phases of falling coincide with minima in solar activity. Not impressive evidence.
  • Sunspot cycle 20 is smaller than most others and coincides with a small rather than a large wobble of the sun about the barycentre. A single data point. Not impressive evidence.
  • During the Dalton minimum in solar activity some unusual sunspot cycles matched some small wobbles around the barycentre.

The figure in McCracken et al isn’t very good so I’ve plotted the sunspot data from WDC-SILSO and the sun-barycentre distance from the Horizon ephemerides. I cannot see any strong relationships here.

Distance between the sun and the barycentre (black) and the mean number of sunspots. red

Distance between the sun and the barycentre (black) and the mean number of sunspots (red). Clear, repeated relationships between the two curves are not obvious.

  • More interesting is the claim that the 20 Grand Minima in the Holocene (including the Maunder Minimum) all occurred during disordered phases of the Sun’s motions. Although this “close association” in figure 7 is not so obvious in the figure 8. McCracken et al rate the probability of the association occurring by chance if the wobble had no effect as 0.01. This is the only evidence I’ve found interesting, but it is hardly conclusive evidence.
McCracken et al Figure 7 The occurrence of Grand Minimum Events within the Jose cycles over the past 9400 years. The vertical dashed line indicates the approximate end of the ordered phase: the dotted lines the occurrence of barycentric anomalies. The open blocks represent periods of increasing cosmic-ray intensity; the solid blue blocks correspond to the periods of highest intensity.

McCracken et al Figure 7 The occurrence of Grand Minimum Events within the Jose cycles over the past 9400 years. The vertical dashed line indicates the approximate end of the ordered phase: the dotted lines the occurrence of barycentric anomalies. The open blocks represent periods of increasing cosmic-ray intensity; the solid blue blocks correspond to the periods of highest intensity (ie solar minima).

McCracken et al figure 8. The correspondence between variations in the paleo-cosmic-ray record and features of the Jose cycle for the sequence of Grand Minima in the interval 4000 – 2800 BP. The hashed blocks correspond to the ordered phase of the Jose cycle. The narrow vertical blocks represent the barycentric anomalies; their width indicates their duration. The Jose Cycles (JC) are numbered from the beginning of the Holocene.

McCracken et al figure 8. The correspondence between variations in the paleo-cosmic-ray record and features of the Jose cycle for the sequence of Grand Minima in the interval 4000 – 2800 BP. Hashed blocks correspond to the ordered phase of the Jose cycle; narrow vertical blocks represent the barycentric anomalies. Jose Cycles (JC) are numbered from the beginning of the Holocene.

So out of the six lines of evidence in McCracken, only one is in the least interesting, meriting some further investigation. The other five lines are very dubious.

Finding patterns of planetary dynamics that correlate with solar activity is easy. There are a multitude of patterns, some are bound to correlate (occasionally, at least if you squint). Testing if these patterns are real is complicated by the lack of a suitable test case – using the same data for exploratory analysis and confirmatory analysis is an easy way to get Type 1 errors, results that appear to be statistically significant but are no more than by chance. Fitting models with half the data and testing the fit for the other half would be a good strategy (but no peeping allowed).

One of two things is required to make planetary-solar interactions convincing 1) good predictions of the next few sunspot cycles, 2) a physical model of solar activity that can only match observed record of solar activity when planetary alignment is considered. The first will take decades to be realised, so might the second.


Abreu J.A., Albert C., Beer J., Ferriz-Mas A., McCracken, K.G. & Steinhilber, F. 2012. Is there a planetary influence on solar activity? Astronomy and Astrophysics 548, A88.

Abreu J.A., Albert C., Beer J., Ferriz-Mas A., McCracken, K.G. & Steinhilber, F. 2014. Response to: “Critical Analysis of a Hypothesis of the Planetary Tidal Influence on Solar Activity” by S. Poluianov and I. Usoskin Solar Physics 289, 2343–2344.

McCracken, K.G., Beer J. & Steinhilber, F. 2014. Evidence for Planetary Forcing of the Cosmic Ray Intensity and Solar Activity Throughout the Past 9400 Years. Solar Physics 289, 3207-3229.

Poluianov S. & Usoskin, I. 2014. Critical Analysis of a Hypothesis of the Planetary Tidal Influence on Solar Activity Solar Physics (2014) 289, 2333–2342.

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About richard telford

Ecologist with interests in quantitative methods and palaeoenvironments
This entry was posted in Peer reviewed literature, solar variability and tagged , , , . Bookmark the permalink.

31 Responses to The barycentre strikes back

  1. Of course one basic argument against this kind of effect is that we know how much energy is associated with a planet (orbit, rotation). If a planet is somehow driving energetic processes in the Sun, then you have a bit of a problem explaining where the energy is coming from as we know that the change in the orbit and spin of the Solar system planets is really small (on relevant timescales at least). We also know that the energy in the Sun comes from fusion in its core, which is not (even according to these models) influenced by planetary torques.

    When you were discussing the statistics at the end, it reminded of the look elsewhere effect that they need to consider in particle physics. I think the basic idea is that if you look over as much of energy space as you possibly can, then you have to be slightly careful of 3/3.5 sigma events because the chance of finding such an event over all parameter space, is much higher than of finding such an event if you had pre-specified the region of parameter space that was of interest.

    • Abreu et al invoke the Milankovitch theory as an example of small orbitally forced variations having a large impact that was initially controversial. I’m not convinced that this is a good analogy as with Milankovitch forcing the latitudinal variations in insolation are reasonably large (at least compared with the energy supplied by planetary tides or torque on the sun), and the time scales are long enough for feedbacks to amplify the initial signal.

      The look elsewhere effect is a variant of the multiple testing problem. Its a huge problem both in these papers and in the multitude of papers finding “significant” spectral peaks somewhere in a periodiogram.

      • Yes, I agree with you about the Milankovitch cycles. The change in forcing in the regions where it can act to melt ice is substantial, and so it isn’t clear that it is a good analogy. To be fair, though, my understanding is that there still isn’t a completely convincing explanation for the Milankovitch cycles, but – I think – there are some recent papers (the authors of which I can’t quite remember) that are starting to present some quite reasonable scenarios.

      • Its mainly the 100ka cycle (the change in the orbit from near circular to more elliptical) that is curious as the insolation changes associated with it are rather small yet it is the dominant cycle during the second half of the Pleistocene (but not the first half where the 40ka cycle dominates). This change in dominant period is the subject of much research.

  2. Multiplying the p-values of different analyses together (argument 4) is of course incorrect. Fisher’s method for combining probabilities should be used, otherwise bad things can happen.

  3. Geoff Sharp says:

    If you think Fig 7 is impressive you should perhaps look further. Across the Holocene there are no solar grand minima when Neptune and Uranus are opposing (ordered phase), this is a fact that should make the most skeptical sit up and take notice.
    Grand minima as discovered by Charvàtovà’ decades ago only occur during times of the disordered phase, and now we know that the Barycentric anomaly or AMP event is the cause that occurs on average 3 times during the 150 year disordered phase.
    Understanding the AMP event is the key which can now be quantified so that we are able to confidently predict future solar grand minima as we have done with SC24. I am the original discoverer of this phenomenon (2008) and have a paper published at arxiv (2010) and a peer reviewed version at IJAA (2013).

    http://arxiv.org/ftp/arxiv/papers/1005/1005.5303.pdf
    http://www.scirp.org/journal/PaperInformation.aspx?paperID=36513&#reference

    Neptune and Uranus may be a long way away but with their combined gravity they have a similar effect as Saturn, and can cause the Sun to take a very irregular 10 year orbit about the SSB. When this happens the Sun has less activity in every case.

    You can argue the Sun is in freefall, but there are papers (Wolff & Patrone) that have a physics based mechanism for changes in the solar orbit and a decrease in activity. If you are game I am happy to debate any aspects of my paper.

    • I see your Wolff and Patrone and raise you Callebaut et al 2012.

      The problem with figure 7 is one of multiple testing – there are dozens of combinations of planets that could be tested. The probability that one combination has a good relationship with solar minima is relatively high.
      Neptune and Uranus having an combined influence as large as Saturn would be more interesting if the tidal influence of Saturn on the tachocline wasn’t an order of magnitude smaller than that of Venus.

  4. Geoff Sharp says:

    Sure we can trade rebuttals and ad hominems etc, but I would prefer to deal with the facts.

    To do that we need to be on the same level, meaning your requirement to read my paper and have a basic understanding.

    I can tell you have not read the paper via two statements:

    The problem with figure 7 is one of multiple testing – there are dozens of combinations of planets that could be tested. The probability that one combination has a good relationship with solar minima is relatively high.

    The theory is totally falsifiable, there is only one planetary configuration that causes the Barycentric Anomaly, N/U/J together with S opposing. This is the only alignment that can cause the altered solar orbit that correlates with solar slow down. (there is one other but it is very rare).

    Neptune and Uranus having an combined influence as large as Saturn would be more interesting if the tidal influence of Saturn on the tachocline wasn’t an order of magnitude smaller than that of Venus.

    This is not about tidal forces, its about the altered path of the Sun. Only the gas giants can do that.

    Please read the paper and get back to me. The data is strong, still waiting for someone to prove otherwise.

    • So Callebaut et al 2012’s rebuttal is not a fact? Certainly it is a fact that my reply contained no ad hominems.

      Why do you want a palaeoecologist to find the holes in your paper, is it because the solar physicists are too cruel to it? Is that why it ended up in a predatory journal? Did the peer review there amount to more that checking that your cheque didn’t bounce?

      I tell you what, if I bump into Leif Svalgaard after his presentation at EGU, I’ll ask him what he thinks of your paper.

    • Dmh says:

      Why the altered solar orbit causes slowing down of solar activity? What is the physical mechanism that, in your understanding, connects the two phenomena?
      Do you think the alteration of the tachocline important, or not?

  5. Geoff Sharp says:

    Callebraut (2012) does not deal directly with Wolff & Patrone and mainly addresses the tidal problems, which I probably agree with.

    You certainly are now stooping to ad hominem by attacking the journal and the peer review process. The McCracken et al paper is almost identical to mine and took over 18 months in the Solar Physics peer review system.

    You are the one posting a blog review on the McCracken et al paper, which you are now running away from. Have a look at the important facts contained in the papers and offer a rebuttal if you want to be taken seriously, the main fact is that the Barycentric Anomaly coincides with all solar slow downs across the Holocene solar proxy record and the more recent sunspot record. Prove that point wrong before addressing any other issue.

    Watts, Svalgaard and Eschenbach so far have not had the courage to review the McCracken et al paper or my own, there has also been no rebuttal in the literature. Sometimes the truth is too hard to swallow?

    Dmh. Wolff & Patrone claim to have a physical mechanism, it may or may not be the ultimate answer. If the the correlations are good enough to hindcast the Holocene and accurately forecast the future (as it is with SC24) the theory demands attention. At present there is no other theory which can make such claims. Of interest is the change in the tachocline at present, which currently shows via the doppler images (Howe & Hill) a lengthening of the torsional oscillation flows towards the solar equator. The flows are generated at the tachocline and take 2 years to surface and are the platform for sunspot activity. There is a change at the tachocline happening right now.

  6. Geoff Sharp says:

    Not sinking without a trace here, and yes my paper was peer reviewed…I have over 10 citations including the McCracken paper, which is a carbon copy of my own, and went through 18 months of peer review at Solar Physics.

    I was also invited recently to give a presentation on my paper at the largest Astronomical Society in the Southern Hemisphere. Perhaps its time for you to get off the smart comments and explore the new science.

  7. Influence of the planet Mercury on sunspots, Bigg, E. K., Astronomical Journal, Vol. 72, p. 463 (1967) and Solar Orbital Angular Momentum and Some Cyclic Effects on Earth Systems,

    I’ve always thought that Bigg fairly conclusively showed that Mercury has some effect on sunspots. He also noted that other planets enhanced or suppressed the ‘Mercury effect’ depending on their position relative to Mercury.

    Bigg though posited that this effect was probably more timing than causation.

    It is of course another leap to go from sunspot activity to a significant effect on the earth’s climate.

    As for solar angular momentum, per Windelius and Carlborg 1970-2040 should be a cooling phase. “Calculations of the changes in angular momentum (L) in the Sun’s orbit around the solar system center of mass (CM, or barycenter) disclose more or less regular phase changes. Five such changes occurred during the last four centuries, around AD 1600, 1690, 1780, 1870, and 1970. These changes separate general climatic trends on planet Earth, designated here as “disharmonic” (cool), e.g. ca. 1600–1690, 1700–1870 and 1970–2040; and alternating with “harmonic” (warm), e.g. 1700–1780, and 1880–1960.”

    • Bigg postulate that Mercury influences solar activity, Windelius & Carlborg postulate that it is the giant planets. Neither paper looks very robust. Bigg’s hypothesis would be easy to test as there are 55 years more data (>200 Mercury orbits). Windelius & Carlborg is badly written, claiming far more than it demonstrates and goes mad claiming that volcanism and seismic activity are under the influence of lunar and solar cycles.

  8. Geoff Sharp says:

    The pioneers of planetary science gave us some hints, but most were wrong. Charvatova was the closest, but did not understand what caused grand minima inside her disordered phase.

    When it comes to angular momentum there is one simple rule, J+U+N with S opposite causes a perturbation in the Angular Momentum curve which can only occur inside the Charvatova disordered phase. When this perturbation happens the Sun slows down every time…I challenge anyone to prove me wrong.

    • So angular momentum is conserved, but the sun doesn’t exactly come to a juddering halt does it. I presume you have done the calculations – just how much does the solar rotation rate change by and is there any physical mechanism that can cause this (presumably very small) difference to have a large impact on solar activity?

  9. Geoff Sharp says:

    Typical argument from those not willing to look at the facts. If I teleported you around the world in 3 seconds I could imagine you coming back and refusing to admit it happened because I did not have a formula to prove it.

    I gave you a challenge, prove me wrong…

  10. Geoff Sharp says:

    I’ll make it easy for you. You have the power to show the following graph.

    The planetary position I described is at the green arrows. The Sun slows down every time, show me where i am wrong?

  11. Geoff Sharp says:

    And if you want rotational rate change, check this out.

    Torsional oscillation zonal flows (equatorial rotation rate) measured (Antia et al) on the Sun show SC24 is slower than SC23. The preflows for SC25 are missing showing that SC25 is even slower again. All this is happening when the Sun is on a different path to the usual when J+U+N with S opposite.

  12. Geoff Sharp says:

    Very poor come backs Richard, hiding behind a physical mechanism is pathetic. I have already provided Wolff & Patrone, who are still unchallenged in the literature. If you think otherwise, provide the actual words from a rebuttal paper aimed at Wolff & Patrone.

    Torsional oscillation changes could be related to a change of rotation rate at the Tachocline, this is still an area of the unknown. The inner 75% rotates as a solid with the zonal flows rising from the sheer layer, the zonal flows are a measured physical change aligning with the disordered inner orbit.

    You have not commented on the Angular Momentum Perturbations at the green arrows that line up with all solar slow downs during the 400 year sunspot record. We can go back right over the Holocene if you wish for a larger window? This is the same logic as the McCracken graph that you found “interesting”. Click on the AM graph provided yesterday to see the extra detail including the same Charvatova “Ordered Phase” where grand minima cannot occur. This is all compelling evidence that you are evading… because you have no answer?

    • You think that asking for a physical mechanism is pathetic. Would that be because you don’t have one that is in the least plausible. Perhaps you would prefer magic mechanisms instead.

      You have read Callebaut et al haven’t you.

      • Geoff Sharp says:

        yes we have already discussed this…the Callebaut paper does not rebut Wolff & Patrone. Copy and paste the text that deals with Wolff & Patrone from the paper if you disagree.

  13. Geoff, as I quoted above, Windelius and Carlborg cited Solar Angular Momentum and determined that 1970 – 2040 would be a period of cooling. How has that worked out?

    • Geoff Sharp says:

      Kevin, they were not the first to get angular momentum theory wrong. Jose, Wood and Blizzard also predicted solar grand minimum for SC21,22&23. Landscheidt and Fairbridge predicted a Grand minimum for 1990 and Charvatova predicted a high cycle for SC24.

      The pioneers got it wrong but were on the right track, but because of the failed predictions were seen as a bunch of pseudo-scientists. The new science is completely different and now offers solid data that Richard cannot fault.

      • A palaeoecologist is hardly your target audience. If you persuade the solar physicist community that you are not pushing pseudoscience then I will follow their lead.

  14. Geoff Sharp says:

    We also have discussed this…you wrote the article suggesting the paper is bogus. I am defending the paper along with my own. As you have not been able to find fault in data presented we will assume you cannot do so. Your article is busted for the fraud that you are.

    It would seem the Barycentre has indeed struck back….

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