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Originally Posted by Hornblower
My question again: How would the gravitational action of the planets have any effect on the Sun's electrodynamics?
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The patterns are largely explicable by gravity. The tendency of sunspot minima to align with barycentric maxima and minima is very strong. To my lay imagination, it looks a bit like a bungee jump where the stress on the jumper is maximised at the turning point, except for the sun for some reason this point of stress coincides with lesser activity. The stress on the sun of the reversal of direction of movement of the barycenter looks to be a key factor in the timing of sunspot minima.
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Gravity does not move the barycenter. It moves the Sun and the planets, while the barycenter's motion remains inertial, in accordance with the law of conservation of momentum. For the purpose of this analysis we can treat the barycenter as stationary.
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Except that there is a clear statistical correlation between the barycentric pattern and sunspot cycles. If the barycenter is a function of solar system gravity, it makes sense to say gravity moves it. It is wrong to treat the barycenter as stationary when its movement looks to be a determining correlate for sunspot activity.
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The separation of the barycenter and the Sun's center is immaterial. The barycenter is not a perturbing object. As I have argued before, all the Sun ever "feels" is a very small amount of tidal stretching because of a slight gravity gradient that is smoothly distributed over its volume.
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The tidal stretching may be small in % terms but is immense in mass.
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Suppose we have a simplified model consisting only of the Sun, Jupiter and Saturn, with the planets in circular orbits. The Sun would experience spring tides with the planets in conjunction and again with them on opposite sides, of virtually the same amplitude. The fact that the barycenter would be much closer to the Sun's center in the latter is immaterial. With the planets at quadrature we would have neap tides. The complete conjunction cycle, with two spring tides and two neap tides, is about 20 years.
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JimP’s response to my question on tides showed that the spring-neap quadrature cycle is not an apparent factor, but that the conjunction and opposition of Jupiter and Saturn look highly determinant for both the barycenter cycle and the sunspots
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Do these tides, whose tiny magnitude I mentioned in an earlier post, have any observable periodic effect on the electrodynamics of the Sun's innards? Do the vastly stronger tides on Earth, as reckoned in proportion to its mass, have any analogous effect? I have never heard of any suggestions of the latter, so I remain immensely skeptical about the former.
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There is an astoundingly clear similarity in pattern between the two 180 year sunspot cycles for which we have data. The movement of the barycenter, caused mainly by the big planets, correlates precisely with sunspot timing. I am not sure that the example of terrestrial tides is very informative, given that earth is so much smaller and denser than the sun.
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Once again the appearance of a statistical correlation is not necessarily evidence of causality. Two independent, roughly periodic cycles could fortuitously have nearly enough the same period to give a false positive over the period under study. For all we know, if we had accurate enough data to go back through the Maunder minimum and earlier, the correlation found here might fall apart.
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Yes, except that the tendency of sunspot minima to correlate with barycentric maxima and minima is very strong.
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I cannot evaluate the merits of the statistical findings in the last few posts any more than I would have been able to comprehend a printed copy of a Beethoven piano sonata after a few piano lessons as child. I simply do not have the training or skill in this field. I would have to yield to independent, unbiased statisticians to judge them, should any wish to take the trouble to do so.
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The statistics I presented previously were very simple. On the null hypothesis of no link between sunspot cycles and the barycenter, half the sunspot minima should be during the quartiles where barycenter is at a local maximum or minimum. The data shows that most sunspot minima are in these quartiles, with a result, from a rough initial look, that would occur in only 1.5% of cycles by chance. With more time I would like to test this in more detail against the data, but it looks persuasive for a clear observable link between sunspot minima and barycentric radius.
Wikipedia comments at
http://en.wikipedia.org/wiki/Sunspot#Sunspot_variation “It has been speculated that there may be a resonant gravitational link between a photospheric tidal force from the planets, the dominant component by summing gravitational tidal force (75%) being Jupiter's with an 11 year cycle”. Wainwright, G. (2004). Jupiter's influence. New Scientist 2439, 30. This article is as follows
Jupiter's influence, 20 March 2004 , From New Scientist Print Edition. Glyn Wainwright, Leeds, UK : While the work of Mausumi Dikpati suggests that meridional flows in the sun's convective layer may allow us to forecast sunspot activity (6 March, p 38), other forces may also be at work. In particular, the giant planets in the solar system may play a role through the gravitational pull they exert on the massive amount of fluid flowing in the outer layer of the sun. Curiously, this gravitational force can be expressed as a Fourier series whose most important terms have interesting periodicities: one of these coincides with the 11-year cycle of the sunspots. What we may be seeing, therefore, is the direct influence of planetary tidal forces and their effects on the stability of the magnetic loops created in the meridional flows in the sun's convective layer. These forces could be a major factor in the cycle of magnetic loops believed to create the sunspots. Jupiter is the largest contributor to the solar plasma tides. It may eventually transpire that its influence contributes to our climate.
From issue 2439 of New Scientist magazine, 20 March 2004, page 32