Planetary effects are too small by several orders of magnitude to be a main cause of the solar cycle.
Argiris Diamantis writes in with this tip:
Professor Cornelis de Jager from the Netherlands has put a new publication on his website. It is a study of Dirk K. Callebaut, Cornelis de Jager and Silvia Duhau. They conclude that planetary effects are too small by several orders of magnitude to be a main cause of the solar cycle. A planetary explanation of the solar cycle is hardly possible.
The paper is titled:
The influence of planetary attractions on the solar tachocline
Dirk K. Callebaut a, Cornelis de Jager b,n,1, Silvia Duhau c
a University of Antwerp, Physics Department, CGB, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
b Royal Netherlands Institute for Sea Research, P.O. Box 59, NL 1790 AB Den Burg, The Netherlands
c Departamento de Fı´sica, Facultad Ingeniera, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
We present a physical analysis of the occasionally forwarded hypothesis that solar variability, as shown in the various photospheric and outer solar layer activities, might be due to the Newtonian attraction by the planets.
We calculate the planetary forces exerted on the tachocline and thereby not only include the immediate forces but we also take into account that these planetary or dynamo actions occur during some time, which demands integration. As an improvement to earlier research on this topic we reconsider the internal convective velocities and we examine several other effects, in particular those due to magnetic buoyancy and to the Coriolis force. The main conclusion is that in its essence: planetary influences are too small to be more than a small modulation of the solar cycle. We do not exclude the possibility that the long term combined action of the planets may induce small internal motions in the sun, which may have indirectly an effect on the solar dynamo after a long time.
From the Introduction:
So far the study of solar variability has identified five solar periodicities with a sufficient degree of significance (cf. the review by De Jager, 2005, Chapter 11).
These periods are:
- The 11 years Schwabe cycle in the sunspot numbers. We note that this period is far from constant and varies with time, e.g. during the last century the period was closer to 10.6 years.
- The Hale cycles of solar magnetism encompasses two Schwabe cycles and shows the same variation over the centuries.
- The 88 years Gleissberg cycle (cf. Peritykh and Damon, 2003). Its length varies strongly over the centuries, with peaks of about 55 and 100 years (Raspopov et al., 2004). The longer period prevailed between 1725 and 1850.
- The De Vries (Suess) period of 203–208 years, with a fairly sharply defined cycle length.
- The Hallstatt cycle of about 2300 years. An interesting new development (Nussbaumer et al., 2011) is the finding that Grand Minima of solar activity seem to occasionally cluster together and that there is a periodicity in that clustering. An example of such a cluster is the series of Grand Minima that occurred in the past millennium (viz. the sequence consisting of the Oort, Wolf, Sp¨ orer, Maunder and Dalton minima). This kind of clustering seems to repeat itself with the Hallstatt period.
It should be remarked in this connection that virtually none of the papers on planetary influences on solar variability succeeded in identifying these five periodicities in the planetary attractions.
Another approach to this problem is the study of climate variations in attempts to search for planetary influences. As an example we mention a paper by Scafetta (2010), who found that climate variations of 0.1–0.25 K with periods of 20–60 years seem to be correlated with orbital motions of Jupiter and Saturn. This was, however, not confirmed in another paper on a similar topic (Humkin et al., 2011). This is another reason for a more fundamental look at the problem: can we identify planetary influences
by looking at the physics of the problem?
The challenge we face here is twofold: planetary influences should be able to reproduce at least the most fundamental of the five periodicities in solar variability, and secondly the planetary accelerations in the level of the solar dynamo should be strong enough to at least equalize or more desirably, to surpass the forces related to the working of the solar dynamo. In this paper we discuss the second aspect, realizing that the attempts to cover
the first aspect have been dealt with sufficiently in literature while the second aspect was grossly neglected so far. A first attempt to discuss it appeared in an earlier paper (De Jager and Versteegh, 2005; henceforth: paper I). They calculated three accelerations:
1) One by tidal forces from Jupiter. They found aJup=2.8=10^-10 m/s^2.
2) One due to the motion of the sun around the centre of mass of the solar system due to the sum of planetary attractions (ainert).
3) The accelerations (adyn) by convective motions in the tachocline and above it.
It was shown in their work that the third one is larger by several orders of magnitude than the first and second mentioned accelerations. Soon after its publication it was realized that some of the forces are effective for a long time, which demands an integration of the forces over the time of action. That might change the results. It was also realized that more forces may be operational than the two mentioned in paper I. Therefore, in the present paper, we improve and expand these calculations; we investigate a few more possible effects; moreover, we study the effect of the duration of these actions as well.
We calculated various accelerations near or in the tachocline area and compared them with those due to the attraction by the planets. We found that the former are larger than the latter by four orders of magnitude. Moreover, the duration of the various causes may change a bit the ratio of their effects, but they are still very small as compared to accelerations occurring at the tachocline.
Hence, planetary influences should be ruled out as a possible cause of solar variability. Specifically, we improved the calculation of ainert in paper I and gave an alternative estimation. If the tidal acceleration of Jupiter were important for the solar cycle then the tidal accelerations of Mercury, Venus and the Earth would be important too. The time evolution of the sunspots would then be totally different and the difference between the
solar maximum and its minimum would be much less pronounced.
Taking into account the duration of the acceleration aJup does not really change the conclusions of paper I: the planetary effects are too small by several orders of magnitude to be a main cause of the solar cycle (they can be at most a small modulation); moreover,
they fail to give an explanation for the polarity changes in the solar cycle. In addition, the periods of revolution of the planets (in particular Jupiter) do not seem compatible with the solar cycle over long times. In fact, a planetary explanation of the solar cycle
is hardly possible. Besides, we estimated various other effects, including the ones
due to the magnetic field (buoyancy effect and centripetal consequence)
and those due to the Coriolis force; their relation to the tidal effects can be indirect at its utmost best (by influencing motions which might affect the solar dynamo).
As all planets rotate in the same sense around the sun their combined action over times of years may induce a small motion e.g. at the solar surface. This may have an influence on the meridional motion or on the poleward motions of the solar surface (Makarov et al., 2000), having in turn an influence on the solar dynamo (maybe leading to an effect like the Gnevyshev–Ohl rule). Again, this will be very indirect and the effect of one planet or one orbital period will be masked.
Looks to me like Barycentrism just took a body blow – Anthony