How can Jupiter and Saturn affect the timing of solar cycles?: Brief review

Posted: March 22, 2012 by Rog Tallbloke in Astrophysics, Electro-magnetism, Energy, Gravity, methodology, Solar physics, solar system dynamics, Tides

According to what we know so far, if the motion of planets is affecting solar variability as the myriad correlations which have been discovered suggest they are, then it must be via  one or a combination of the known forces: Gravitation, Tides, Electromagnetism.

Because our knowledge is so incomplete, the safe way to proceed is to not rule out any of these possibilities, but to investigate, compare observations, make some logical deductions and inferences, and draw up some tentative hypotheses.

Since it is topical, I’ll concentrate on Jupiter and Saturn in this post. In an earlier post, and in Nicola Scafetta’s paper currently under discussion, it has been shown that the periods around the solar cycle length apparent in spectral analysis of the sunspot record closely match periods related to these gas giants. This makes immediate sense, they are the two biggest planets in the solar system. But although they have the biggest and second biggest effect on the Sun gravitationally, in terms of tidal strength, Jupiter is way more powerful than Saturn, and Saturn’s tidal force on the Sun is much smaller than Venus Earth, and even tiny Mercury, as Ian Wilson showed recently.

Both Jupiter and Saturn (and Earth) display strong auroral lights near their poles. This is an indication that strong interactions are occurring between the Sun and these planets. If electro-magnetism is important in the proposed planetary effects on the Sun, we should be able to find other evidence which indicates this.

Our old friend Vukcevic made an interesting discovery some time ago. He looked at the separation angle between Jupiter and Saturn at solar cycle minimum two ways. The first was the simple geometrical angle made in space. the second was he called ‘the magnetospheric angle’ (I think I would call it the helio-magnetic angle), which he measured along the Parker Spiral, which is the spiral of differentiation in the flow of the varying strength of the solar wind relative to the stellar background. It is spiral because it moves outwards as the Sun spins on its axis. This revealed something very interesting, as the two plots below show.

As you can see, the second plot, measuring angles along the Parker Spiral, is much more coherent and regular, demonstrating a potential relationship between the relative positions of Jupiter and Saturn, and the occurrence of Solar cycle minimum, which is electromagnetic in nature.

This inference is supported by an investigation I made independently of Vuk’s work (which I didn’t know about at the time), looking at the Jupiter – Earth – Venus cycle using Roy Martins alignment model. Roy’s model contained weighting for the influence of the planets, which he had set up for tidal influence. I adjusted these values, reducing Venus’ influence as it has very little magnetosphere of its own, and setting the angles between planets to lie along the Parker Spiral instead of in straight geometrical lines. The result was startling, and improved further when I adjusted the output data to account for variation in solar wind-speed. I used Leif Svalgaard’s reconstruction, extended further back in time with that of Rangarajan  and Baretto.

It seems that as well as Jupiter and Saturn, Jupiter and Earth have a lot to do with the timing of solar cycles and their profile, although amplitude is clearly another matter, perhaps being affected by the same planets in a different way, or by other planets through other fundamental forces.

All in all, I’m inclined to the view that the timing of solar cycles is  being modulated more strongly by electromagnetic forces than by tides or gravity. What is also clear from the data I have studied, is that this relationship gets strained when other planetary factors occasionally impose, as at the onset of the Dalton minimum, and perhaps around now, around one de Vries cycle later. That’s for another thread.

Comments
  1. Gray says:

    Hi tallbloke. I think this is undoubtedly the question to ask. I was recently dabbling with the Mars and Jupiter conjunctions and found a potential link between the orbital distance of both Mars and Jupiter in the solar cycle. By taking the degree using the ecliptic grid at which each conjunction occurred from 1749 to current and relating the sunspot level to the position it is possible to see a single peak of sunspots which encompasses the most distant orbital points of both planets. Whether this is an artefact of the data is hard to determine however it raises a couple of questions.

    If the solar cycle is predominant when Jupiter and Mars are distant from the Sun could the slower speed at which the planets are then traveling enable a magnetic reconnection to take place. Firstly by maintaining their slower traveling speed in unison and secondly by enabling the innermost planets to pass inside them more frequently.

    The second is the emergence of solar activity at a higher solar latitude at the start of a cycle moving to the solar equator for the end of a cycle. Could the slower surface rotation of the Sun match the planet’s position re the Parker spiral first, moving to the faster equator as the planets extend the spiral.

    Comparatively Mars itself would have very little tidal effect on the Sun.

  2. vukcevic says:

    Hi Tb
    If you use this link
    http://www.vukcevic.talktalk.net/J-S-angle.htm
    it shows Parker spiral animation, so it can be better appreciated what is involved.

  3. vukcevic says:

    See also:
    http://en.wikipedia.org/wiki/File:Heliospheric-current-sheet.gif
    The ‘ballerina skirt’ was apparently designed with the guidance from our nemesis L.S.

  4. Ninderthana says:

    Tallbloke and Vukcevic,

    You have proposed some very cogent arguments in favor of the magnetosphere model.

    However, just to set a few cats among the pigeons, here are few points:

    Wilson et al. (2008) empirically showed that the Sun’s rate of spin is synchronized
    with motion of the Sun about the Barycentre of the solar system – such a relationship
    is far more likely to arise from tidal-torquing (i.e. a spin-orbit coupling) that is more likely
    driven by gravitational/tidal interactions (rather than magnetic) interactions between
    the planets.

    The magnetic interaction forces acting between planetary dipoles fall off as 1/R^3 and
    so they should be just as insignificant as the tidal forces

    The V-E-J orbital cycles naturally produces many of the characteristics of the solar cycle
    (see the Wilson (2010) General Sciences Journal paper) including the 11.1 year solar
    cycle length. Given that Venus has no significant magnetosphere, it is hard imagine why
    this would be the case if the level of solar activity was solely driven by magnetic interactions
    between the planets.

    The strength of the magnetic fields of the Sun, Earth, Jupiter and Saturn are are a reflection
    of the spin rates of these bodies, while variations in the strength of the solar cycle appears
    to be linked to synchronicity between the orbital periods of Venus, Earth, Jupiter and Saturn.

    Again, this implies a spin-orbit coupling between Sun’s rotation rate and its orbital motion
    about the barycentre of the Solar System – something that favors a gravitational/tidal origin
    to the whole process.

  5. Ninderthana says:

    P.S.

    Don’t get me wrong here. I would be happy if either the gravitational/tidal model or the magnetospheric model (or even both) was/(were) correct. I am primarily interested in showing
    that the solar cycle is either moderated or driven by influences from outside the Sun.

  6. Stephen Richards says:

    one or a combination of the known forces: Gravitation, Tides, Electromagnetism.

    Gravitation and tides are cause and effect. Same thing essentially.

    From Einstein’s theory of relatively one can calculate directly the gravitational forces exerted on the sun by a single object or multiple objects, however, bear in mind the mass ratios of our solar system.

  7. tallbloke says:

    Hi Stephen, quite so, but it’s also worth remembering that while the Sun has over 98% of the solar system mass, it has less than 2% of it’s angular momentum.

    I’m with Ninderthana, we’re sure the solar cycle is modulated by the planets. How the forces shift the energy required, and how much energy is required, are open questions.

    Gray, good to see you back here. We are going to be returning to the solar system dynamics emphasis, so I hope there will be plenty of interest for you.

    Vuk: I wasn’t sure about your animation, the spirals seemed to be moving with the planets Earth and Mercury, rather than at the speed of solar rotation. What are you showing with it?

  8. vukcevic says:

    Ninderthana says: March 22, 2012 at 11:51 am
    ……
    Here is short overview.
    I don’t think the magnetic feedback idea is clearly understood. Gravity acts in straight line so it does magnetic field if you consider sun and planets as bar magnets.
    This is not what magnetospheric feedback is about.
    ‘Magnetic ropes’ emanating out of the sun, are linked to the sun by combination of electric current and magnetic field and they move along solar magnetic field lines (Parker spiral, see wikipedia).
    http://ase.tufts.edu/cosmos/pictures/Sept09/Fig8_7.MagCloud.gif
    Now look at this NASA animation.

    If the ‘m. rope’ doesn’t hit a magnetosphere it progresses to the far reaches of the heliosphereand disperses along the heliopause. But if it does hit a magnetosphere, a reconnection ensues, than ‘bang’!, part of it is short circuited and the energy is discharged.
    http://www.igpp.ucla.edu/public/THEMIS/SCI/Pubs/Nuggets/reconnection/262351main_reconnect.mpg
    Nothing controversial to this point.
    What I claim is:
    since ‘magnetic rope’ is connected to the source, the short circuit effect is transmitted back to the solar surface.
    I suggest to those not convinced, NOT to try to short circuit their cold car battery few times and see if it gets warmer, but if you persist with test, you will need to invest some money in a new battery.
    Svalgaard and Hathaway say: this can’t happen since solar wind doesn’t allow anything electromagnetic to move upstream i.e. against the solar wind, back to the sun.
    I say: nonsense, solar wind gets swept out of the way by the CME ( e.g. , day the solar wind died, Forbush etc).
    Gravitation is only important as far as it moves J & S around, so orbital parameters get J/S in right place on the spiral to act together and kill the cycle.
    I mast stop rambling for too long.

  9. vukcevic says:

    The strength of the magnetic fields of the Sun, Earth, Jupiter and Saturn are are a reflection
    of the spin rates of these bodies

    Earth’s magnetic field strength lost more than 10% since 1850s

  10. vukcevic says:

    tb
    Animation was recorded from NASA and shows parker spirals that links those planets to the sun.
    I’ll have to look for original link, but in meantime this will do:
    http://iswa.gsfc.nasa.gov:8080/IswaSystemWebApp/iSWACygnetStreamer?timestamp=2038-01-23+00%3A44%3A00&window=-1&cygnetId=261
    also showing ones linking the planets and two satellites to the sun (dotted lines).

  11. vukcevic says:

    You can see the core of the CME ejected in ~ 10 o’clock direction, ends ~ 12 o’clock by the time it moves outside the Mars’ orbit, as well as moving solar wind out of the way.
    http://iswa.gsfc.nasa.gov:8080/IswaSystemWebApp/iSWACygnetStreamer?timestamp=2038-01-23+00%3A44%3A00&window=-1&cygnetId=261

  12. Brian H says:

    Small noodges, rhythmically applied over billions of years, will have their way!

    It’s not the real-time magnitude that’s critical; it’s the pattern’s consistency.

  13. vukcevic says:

    Brian
    Do you live in the place called Jupiter in Florida?

  14. Tenuc says:

    tallbloke says:
    March 22, 2012 at 1:01 pm
    “Hi Stephen, quite so, but it’s also worth remembering that while the Sun has over 98% of the solar system mass, it has less than 2% of it’s angular momentum…”

    Yes, the sun has most of the mass, and shares that 2% of angular momentum with the rest of the non-Jovian planets and debris. Anyone know how much inertia the sun has and how this inertia could effect its orbital trajectory?

  15. Doug Cotton says:

    A very interesting article, which, in conjunction with Scafetta’s, strongly supports the view that natural cycles completely control climate without any “help” at all from carbon dioxide.

    It might be worth mentioning that the mathematical calculations of tidal forces due to gravity give a very different result from gravitational attraction. The moon mostly controls ocean, atmospheric and solid Earth tides because the Sun’s tidal effect is only about 48% of that of the Moon, but of course its gravitational attraction is many times greater.

    It is mostly Jupiter which affects the eccentricity of Earth’s orbit which varies in cycles of about 100,000 years I understand. This could also affect the mean solar intensity received by Earth each year, and some think this may have a connection with glacial periods, though this is by no means certain, as far as I know.

    One other possibility of direct influence on Earth could be due to atmospheric tides and solid Earth tides which involve movement of the crust each day. Obviously the Moon is by far the greatest influence, but, never-the-less the total effect of Jupiter and perhaps Saturn could make very small differences in the energy generated at the margin. Seeing that this slight difference would compound over thousands of revolutions of the Earth in just a decade or so, it just might affect climate. Alternatively, there could be a direct effect on Earth’s magnetic field which somehow affects ionization in the upper atmosphere, which might affect clouds or something. I just mention this because I feel there might be a more direct influence (rather than via the Sun) that causes the 60 year cycle and maybe other short-term ones.

  16. gallopingcamel says:

    Gravity rules! The sun is a huge spherical resonator so even quite small gravitation excitations cause it to quiver like a jelly.

    The gravitational stimuli set up eigenstates (cf. standing waves in one dimension). The vibrations are transmitted mostly as p-waves (like sound in Earth’s atmosphere) with little in the way of shear (s-wave) content. The sun is vibrating like a drum so that the surface moves radially.

    These radial motions can be detected by the Doppler shift of light emitted from small areas of the sun’s surface. See:
    http://en.wikipedia.org/wiki/Helioseismology

    I think most of you know all this. So what you say?

    The sun is constantly emitting matter as well as photons. We know that the photon output is very stable so that the TSI measured in Earth’s orbit is around 1,361-1,367 Watts/m^2. Clearly not nearly enough variation to account for observed fluctuations in global surface temperatures.

    What about the matter that the sun ejects? I suggest that the p-wave eigenstates have some influence on this “solar wind”. What the modulation mechanism may be is beyond my pay grade as a humble photon jock. The matter ejected may be charged or neutral. Most of the charged particles will be returned to the sun owing to its magnetic field.

    However, spatial and temporal variations in the sun’s magnetic field will modulate the amount of ionized material in the solar wind. Bottom line, the variations in solar wind flux may be much larger in percentage terms than the variations in TSI.

    Now all you need is a theory to explain why solar wind should affect Earth’s climate. May I recommend Nir Shaviv, the Danes (Friis-Christianson et al.) and Jason Kirkby (CLOUD experiment at CERN).

    As I said once before it is a long chain of conjecture but the CO2 meme has totally failed so what else have you got?

  17. Tenuc says:

    “Solar Storm Dumps Gigawatts into Earth’s Upper Atmosphere”
    “For the three day period, March 8th through 10th, the thermosphere absorbed 26 billion kWh of energy. Infrared radiation from CO2 and NO, the two most efficient coolants in the thermosphere, re-radiated 95% of that total back into space.”

    Source: Martin Mlynczak, NASA Timed satellite team
    http://science.nasa.gov/science-news/science-at-nasa/2012/22mar_saber/

    CO2 & NO radiated 95% back into space. What happened to the back-radiation towards the surface – perhaps Martin didn’t get the memo… :-)

  18. Hans says:

    vukcevic says: March 22, 2012 at 2:08 pm

    “You can see the core of the CME ejected in ~ 10 o’clock direction, ends ~ 12 o’clock by the time it moves outside the Mars’ orbit, as well as moving solar wind out of the way.
    http://iswa.gsfc.nasa.gov:8080/IswaSystemWebApp/iSWACygnetStreamer?timestamp=2038-01-23+00%3A44%3A00&window=-1&cygnetId=261

    Many thanks vukcevic for pointing at this fantastic NASA information. TB says: All in all, I’m inclined to the view that the timing of solar cycles is being modulated more strongly by electromagnetic forces than by tides or gravity.”

    It is well not to be cock sure of what causes sunspots, CMEs, magnetic field reversals etc. However, some of you favour the opinion that “lining up” of planets does matter. If this is the case gravity is the prime reason for havocs on the solar surface but then the problem in a nutshell is that it is not Newtonian gravity as we know it that causes such upheavals.

    Just look at the CME shown above. Earth, Mercury and Sun was lined up at the evening March 21 around 5 PM if I got it right. Around 11 AM the next morning four planets are approximately lined up namely earth, moon, Mercury and sun. This lining up seems to happen almost exactly when the CME occured. A simple question arises: Is this a coincidence? Can anybody caclulate the probablility that it happened by chance?

    Also observe that there are no celestial bodies in the inner solar system that can move faster (actually having a greater velocity times distance variation) at any time in relation to each other than moon and mercury moving in the opposite directions!

    I am inclined to view the extrodinary electromagnetic phenomena on sun as secondary to (dynamic) gravity impact although this gravity is not the Newtonian static gravity alone but a modified version where the dynamics of celestial bodies are taken into account. Gravity is not well understood by today´s scientists, which is one reason why the search for “dark” matter and “dark” energy goes on.

    It will be interesting to hear what you think of my observation.

  19. Hans says:

    Tenuc says: March 23, 2012 at 7:33 am

    “CO2 & NO radiated 95% back into space. What happened to the back-radiation towards the surface – perhaps Martin didn’t get the memo…”

    No problem. Just use IPCC aritmetics. 95% goes up and 95% goes down. It´s easy.

    There seems to be a quasi seasonal modulation in the CO2 IR signal. Any comments about that?

  20. vukcevic says:

    Here is copy of my post on WUWT:
    http://www.vukcevic.talktalk.net/CMEfeedback.htm
    the same electro – magnetic shock wave that lights up aurora and shifts the Earth’s magnetic pole I suggest is responsible for modulating intensity of solar magnetic dipole .

  21. tallbloke says:

    Ninderthana says:
    March 22, 2012 at 11:51 am
    Wilson et al. (2008) empirically showed that the Sun’s rate of spin is synchronized
    with motion of the Sun about the Barycentre of the solar system – such a relationship
    is far more likely to arise from tidal-torquing (i.e. a spin-orbit coupling) that is more likely
    driven by gravitational/tidal interactions (rather than magnetic) interactions between
    the planets.

    The magnetic interaction forces acting between planetary dipoles fall off as 1/R^3 and
    so they should be just as insignificant as the tidal forces

    Hi Ian, and thanks for your detailed response. I’ve been chewing on it and here are a few points in reply.

    Landscheidt posited the idea that the torquing effect might be due to the Sun’s barycentric motion through it’s own magnetic fields. This gets around the problem of the falloff in strength with distance you mention. Clearly, large amounts of the field are going to move along with the Sun, but speculatively, I can envisage some residual field differentiation due to the persistence of flux resonance in the wider Interplanetary Magnetic Field.

    The V-E-J orbital cycles naturally produces many of the characteristics of the solar cycle
    (see the Wilson (2010) General Sciences Journal paper) including the 11.1 year solar
    cycle length. Given that Venus has no significant magnetosphere, it is hard imagine why
    this would be the case if the level of solar activity was solely driven by magnetic interactions
    between the planets.

    As I outlined in the lead article, I found that the match I got improved dramatically over the match Roy Martin got using tidal parameters when I used the same model of the same cycles but with the parameters set for an electromagnetic scenario.

    This doesn’t invalidate the work others have done in any way. I think it likely that all mechanisms so far considered, tidal, gravi-barycentric, and electro-dynamic are operative, and combine to produce the effects we have observed.

    It could easily be the case that tides are doing the heavy kneading of the ingredients, and that the EM effect is the palette knife shaping the icing on the currant bun (Sun).

  22. Ninderthana says:

    Tallbloke said:

    It could easily be the case that tides are doing the heavy kneading of the ingredients, and that the EM effect is the palette knife shaping the icing on the currant bun (Sun).

    ~~~~~~~~~~~~~~

    That’s as good a description of the what might be happening that I have seen so far.

    Given our woeful state of knowledge, it is probably the best we can do at this stage.

    Let’s hope its not a case of getting our own cake and wanting to eat it as well.

  23. Gray says:

    tallbloke said:

    This doesn’t invalidate the work others have done in any way. I think it likely that all mechanisms so far considered, tidal, gravi-barycentric, and electro-dynamic are operative, and combine to produce the effects we have observed.

    ————-

    I think this is exactly the point in addressing this problem.

  24. Bart Leplae says:

    In my paper: Variations of the Sun Velocity correlate in various ways with the Solar Cycles
    http://www.gsjournal.net/Science-Journals/Essays/View/3647
    I included a reference to: “Solar-Cycle Characteristics Examined in Separate Hemispheres: Phase, Gnevyshev Gap, and Length of Minimum”
    http://arxiv.org/abs/1001.3186

    The abstract of this last document includes “Hemispheric phase differences range from 0 − 11, 0 − 14, and 2 − 19 months for the rising, maximum, and declining periods, respectively.”

    These phase differences seem to be correlated with the variations of the Sun velocity which is mainly driven by J and S. Although the gravitational force induced by S is weaker than the gravitational force induced by V/E, its influence on the velocity of the Sun is more significant because the direction of its gravitational force has a more consistent direction. (Venus and Earth rotate so fast around the Sun that they are ‘undoing’ their own effect of the velocity of the Sun)

    The polar magnetic fields of the Sun (and its reversals) also seem to have a correlation with the variations of the velocity.

    In follow-up of the above comment:
    “Landscheidt posited the idea that the torquing effect might be due to the Sun’s barycentric motion through it’s own magnetic fields….Clearly, large amounts of the field are going to move along with the Sun …”

    It looks like the Sun behaves like a conductor moving in a strong magnetic field whereby the currents in the Sun are induced by the Sun own acceleration/deceleration which in turn would explain why at the moments of the strongest change in velocity, the Hemispheric phase differences seem to be the smallest.

  25. Bart Leplae says:

    The Sun’s Corona
    http://imagine.gsfc.nasa.gov/docs/science/mysteries_l1/corona.html

    “One of the most puzzling features of the Sun is what has been dubbed “the solar corona problem.” There is a region around the Sun, extending more than one million kilometers from its surface, where the temperature can reach two million degrees. ”

    This site (and others covering this topic) point to magnetism as the possible source of the extreme heating.

    So the presence of a strong magnetic field could explain both the origin of the solar cycle and the heating of the corona. This ‘externally induced’ magnetic field would then be strongest at a distance from the Sun (where the Corona temperature is the highest) and decrease in strength towards the Sun.

  26. Ulric Lyons says:

    The easiest way of looking at it is, that low (and usually longer) solar cycles are occurring when Saturn is butting in on the Ju/Ea/Ve syzygies around the peak of each cycle, meaning that there is a Ju/Sa syzygy close to the main Ju/Ea/Ve alignments. Exceptions occur at e.g. when Uranus is also in the alignment with Saturn. A for the tip of the century in this magnetic puzzle, I would predict from the Uranus example that there will also be an exception when Neptune is SQUARE to the Ju/Ea/Ve (plus Saturn) alignments.

  27. Tenuk says:

    Bart Leplae says:
    March 26, 2012 at 9:35 pm
    “…So the presence of a strong magnetic field could explain both the origin of the solar cycle and the heating of the corona. This ‘externally induced’ magnetic field would then be strongest at a distance from the Sun (where the Corona temperature is the highest) and decrease in strength towards the Sun.

    Hi Bart, you could be onto something here. It could be that the Corona indicates the height of the suns magnetosphere and is the area where the solar EM charge field meets the external charge field from the planets and rest of universe. The intense X-ray radiation and subsequent high measured temperature is probably caused by Bremsstrahlung as free electrons are converted to high energy photons in the plasma sheath.

    It’s a shame current physics doesn’t have a good theory for Bremsstrahlung. If it’s discoverer, Nikola Tesla, was still around we’d have a better understanding of solar electromagnetic effects.

  28. Junon says:

    “Magnetic ropes” and “reconnections” do not exist :) Remember that magnetic lines merely serve as a representation of the strength of the field in that space, much like a topographic map’s contour lines. You would not say that the crossing of contour lines *produces* mountains and valleys, would you? Same thing with magnetic field lines. They do not exist in reality. They serve us purely symbolically on a map. The map is not the territory :)

    The proper terms for “magnetic ropes” are “Birkeland currents” and for “magnetic reconnections” it’s “explosive collapse of plasma double layers.” Electricity largely goes unaccounted in space for some reason, probably because so very few working in Astronomy understand it at all. Hence the silliness of magnetic this and thats, ignoring the accompanying electric currents and their effects.

    Please consult the following links:

    http://www.thunderbolts.info/wp/2012/01/04/essential-guide-to-the-eu-chapter-7/

    http://www.libertariannews.org/2011/03/28/magnetic-reconnection-from-the-eu-point-of-view-plasma-cosmology/

  29. adolfogiurfa says:

    It will be refreshing for everyone to read I.Velikovsky´s “Cosmos without Gravitation”:
    http://www.giurfa.com/cosmos_without_gravitation.pdf

  30. My calculations show the moon to have more than double the gravitational effect on the earth than the Sun. Jupiter’s gravitational effect would be measured in millionths compared to the moon. The physical mechanism seems lacking vis a vis gravitation.

    Similarly, the magnetic field of Jupiter does not extend to Earth. Hard to see them interacting.

    Without physical processes, how is this different than astrology?

  31. tallbloke says:

    Hi Kevin and welcome to the Talkshop. Thanks for taking an interest in this old post. Things have moved on, and earlier suspicions of a spin-orbit coupling operating in the solar system have been substantiated by a series of new posts; try this link
    http://tallbloke.wordpress.com/?s=why+phi

    I suggest you scan the list for the older dates on ‘Why Phi?’ posts and work forward

    And specific to Jupiter, the earth-Moon system’s rotation periods, and solar activity, this fresh comment;
    http://tallbloke.wordpress.com/2013/10/15/ian-wilson-connecting-the-planetary-periodicities-to-%ef%bb%bfchanges-in-the-earths-length-of-day/comment-page-1/#comment-61584

    Cheers – Rog TB