From UCAR: Extended solar minimum linked to changes in Sun’s conveyor belt
BOULDER—A new analysis of the unusually long solar cycle that ended in 2008 suggests that one reason for the long cycle could be a stretching of the Sun’s conveyor belt, a current of plasma that circulates between the Sun’s equator and its poles. The results should help scientists better understand the factors controlling the timing of solar cycles and could lead to better predictions.
The study was conducted by Mausumi Dikpati, Peter Gilman, and Giuliana de Toma, all scientists in the High Altitude Observatory at the National Center for Atmospheric Research (NCAR), and by Roger Ulrich at the University of California, Los Angeles. It appeared on July 30 in Geophysical Research Letters. The study was funded by the National Science Foundation, NCAR’s sponsor, and by NASA’s Living with a Star Program.
The Sun goes through cycles lasting approximately 11 years that include phases with increased magnetic activity, more sunspots, and more solar flares, than phases with less activity. The level of activity on the Sun can affect navigation and communications systems on Earth. Puzzlingly, solar cycle 23, the one that ended in 2008, lasted longer than previous cycles, with a prolonged phase of low activity that scientists had difficulty explaining.
The new NCAR analysis suggests that one reason for the long cycle could be changes in the Sun’s conveyor belt. Just as Earth’s global ocean circulation transports water and heat around the planet, the Sun has a conveyor belt in which plasma flows along the surface toward the poles, sinks, and returns toward the equator, transporting magnetic flux along the way.
“The key for explaining the long duration of cycle 23 with our dynamo model is the observation of an unusually long conveyor belt during this cycle,” Dikpati says. “Conveyor belt theory indicates that shorter belts, such as observed in cycle 22, should be more common in the Sun.”
Recent measurements gathered and analyzed by Ulrich and colleagues show that in solar cycle 23, the poleward flow extended all the way to the poles, while in previous solar cycles the flow turned back toward the equator at about 60 degrees latitude. Furthermore, as a result of mass conservation, the return flow was slower in cycle 23 than in previous cycles.
In their paper, Dikpati, Gilman, and de Toma used simulations to model how the solar plasma conveyor belt affected the solar cycle. The authors found that the longer conveyor belt and slower return flow could have caused the longer duration of cycle 23.
The NCAR team’s computer model, known as the Predictive Flux-transport Dynamo Model, simulates the evolution of magnetic fields in the outer third of the Sun’s interior (the solar convection zone). It provides a physical basis for projecting the nature of upcoming solar cycles from the properties of previous cycles, as opposed to statistical models that emphasize correlations between cycles. In 2004, the model successfully predicted that cycle 23 would last longer than usual.
According to Dikpati, the duration of a solar cycle is probably determined by the strength of the Sun’s meridional flow. The combination of this flow and the lifting and twisting of magnetic fields near the bottom of the convection zone generates the observed symmetry of the Sun’s global field with respect to the solar equator.
“This study highlights the importance of monitoring and improving measurement of the Sun’s meridional circulation,” Ulrich says. “In order to improve predictions of the solar cycle, we need a strong effort to understand large-scale patterns of solar plasma motion.”
About the article
Title: Impact of changes in the Sun’s conveyor-belt on recent solar cycles
Authors: Mausumi Dikpati, Peter Gilman, Giuliana de Toma, and Roger Ulrich
Publication: Geophysical Research Letters
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Spector says:
August 17, 2010 at 3:29 pm
They might bounce off each other like billiard balls.
Some say one of them could be so disrupted as to fly apart, the individual pieces transferring some of thier mass to light and losing thier singularity in a ginormous explosion. Quasar?
Hmmm, so if the filament of a light bulb gets hotter it will put out more light and heat.
Doesn’t this leave out what causes the filament to get hotter? Or, in the sun’s case, what drives the changes in the magnetic field and overall energy??
Spector, if the horizon was at a stop it would no longer be a part of our time frame. You can only speculate that it becomes extremely slow. OOOPS, but then, that disallow BH completely dunnit??
Leif Svalgaard says:
August 17, 2010 at 10:05 am
Zeke the Sneak says:
August 17, 2010 at 10:00 am
–the continuous nuclear reaction which is supposed to be powering the sun–
That is what I said. The point is how much it is costing us.
The ‘offensive’ word was ‘supposed’.
About the cost: it is tiny compared to what society is willing to spent on other things, e.g. Wars, Bailouts, etc.
____________________________________________________
It would be very tiny if we start building nuclear power plants again to supply all our electricity and stop using coal and oil. I really rather see oil turned into plastics rather than burned.
RE: kuhnkat: (August 17, 2010 at 5:07 pm) “Spector, if the horizon was at a stop it would no longer be a part of our time frame. You can only speculate that it becomes extremely slow. OOOPS, but then, that disallow BH completely dunnit??”
The square-root function in the time dilation formula seems to suggest that an approaching photon would run out of distance to go in a finite amount of time.
Ref – Leif Svalgaard says:
August 17, 2010 at 6:59 am
“The latest helioseismology data [presented at SHINE 2010] indicate that there does not seem to be a conveyor belt at all, but rather several cells, both in latitude and more importantly at depth. What we observe at the surface does not seem to reflect very well what goes on deep within the Sun. SDO will in the coming years tell us more about the circulation(s).”
____________________________
Leif –
Do we see similiar cells in the case of Jupiter or are you speaking of something totally new and different, preculiar to the Sun only?
I am not a scientist so I hope I don’t make a fool of myself. Having been convinced by the plasma guys that the Sun is an electrical event and not a nuclear machine, I would speculate that it’s irregularity is driven by the electrical currents of our galaxy and not by the sun burping on hydrogen turning into helium. The image I have in my mind is that the sun is like one of hundreds of billions of x-mas lights, all of the stars in the galaxy plugged into invisible electric currents which drive their power plants. As an electric entity they are supposed to be more like capacitors, if I have understood that theory correctly. When a star blows up it is supposed to be the same as if the load to a capacitor has over loaded its potential and it burns it out. I am simplifying and I hope I am stating it like I read it.
I am not convinced that there is 100% proof that black holes exist. The electric universe plasma models predict that the center of galaxies can be explained in plain electrical ways rather than rely on pulsars, black holes and quasars. It is true that by now our telescopes (functioning in various wavelengths) have witnessed stars in the centre of our galaxy rotating at very high speed around an “invisible” centre. However, this does not mean that they have “seen” the black hole at the centre. They have just seen very fast movements. Likewise with the increasingly sensitive observations of the Crab Nebula; they can certainly see massive streams of opposite directed beams of high energy flows, and they can see a very rapidly spinning “something”. The plasma guys would tell you that it cannot be the actual star spinning that fast because centrifugal force would tear it apart. They speculate that it is a super fast spinning electrical current in a body, a star, that is doing the spinning.
Enneagram says:
August 17, 2010 at 1:07 pm
We are in an epistemological problem about how to disentangle a tangle. In order to achieve such a bliss we should turn our minds blank of any self indulging beliefs and begin from the start again.
BINGO
the tangle cannot be disentangled. we should indeed refuse self deluding beliefs and consider ourselves always at the start!
but alas, some folk are terrified of uncertainty
and prefer their ideas and beliefs over observation and reality
for their beliefs are known, whereas reality is unkowable
fred houpt says:
August 17, 2010 at 7:08 pm
I am not a scientist so I hope I don’t make a fool of myself.
Fred, I’m a scientist and I’ll be the first one to agree that there is much we do not know!
Regarding solar physics, our sun is the only star that we can literally “reach out and touch,” and the far distant bodies must be studied in the condition that they WERE, rather than ARE, due to the incredible distances. Despite these challenges, we are able to generate some very good theoretical physical models for beasties such as black holes etc. Accelerators such as Fermilab and Large Hadron Collider give us much data for what the universe might be doing out there.
There are many unknowns, such as the composition and distribution of “dark matter” throughout the universe. Please see the Fermilab newsletter, this can be obtained for free subscription & contains a wealth of news about the latest discoveries of inner and outer space. I hope you find it interesting! Cheers, Chuck the Dr.P.H.
http://www.fnal.gov/pub/today/
Zeke the Sneak says:
August 17, 2010 at 12:42 pm
However, the type of neutrinos required for the thermonuclear model are not arriving to earth.
Neutrinos oscillate all time even over small distances, so 1/3 of the neutrinos expected from fusion is observed at Earth by a detector only sensitive to that kind, having changed their flavor trillions of times in between. Detectors sensible to all three flavors observe the expected flux.
tallbloke says:
August 17, 2010 at 1:21 pm
Hey, our hypothesis is a good deal older and better developed than your new one
Mine is not new and is developed on a viable physics basis. Your is not, that is the big difference.
has been shown to make useful predictions, unlike your old and now obsolete theory, so take it easy with the putdowns.
You have made no predictions at all, I have made a [so far] good prediction of the small cycle.
I have modified Roy Martin’s calculations to test for an electromagnetic influence rather than tidal and the correlation has got MUCH better.
What can be MUCH better than an ‘amazing correlation that leaves no doubt?
My2Cents says:
August 17, 2010 at 1:28 pm
So what does their predict we can expect (duration and activity) from this cycle?
They make no new prediction, but I predict a maximum of 72 sometime in late 2013.
Richard G says:
August 17, 2010 at 1:34 pm
Does the magnetic disturbance display any cyclonic or anticyclonic behavior? My minds eye pictures a giant magnetic stirring device whirling in the depths of the solar beaker creating a vortex.
Yes sunspots are rotating, and the magnetic field has ‘helicity’ that by the way does not change with the solar cycle. [you would not expect that as the sun still rotates in the same direction.
Pascvaks says:
August 17, 2010 at 6:14 pm
Do we see similiar cells in the case of Jupiter or are you speaking of something totally new and different, peculiar to the Sun only?
We can’t see under the clouds of Jupiter, but such cells are observed on Venus and Earth.
fred houpt says:
August 17, 2010 at 7:08 pm
Having been convinced by the plasma guys
You have been taken for a ride.
neutrinos changing flavor is yet another epicycle, saving the appearance of some pet theory which does not match reality.
here for example is some of the latest reportage:
http://www.livescience.com/strangenews/neutrino-flavor-detection-OPERA.html
not exactly confidence inspiring
observed galaxy rotation curves do not match the theory, so they simply posit dark matter in the required place in the formula to save the theory.
the flavor of neutrinos observed reaching the earth do not match theoretical predictions, so they simply say, “Oh, they change flavor before they got here.”
yeah right.
at least ptolemy was trying to match the theory to reality.
not the other way around.
Nolo Contendere says:
August 17, 2010 at 3:09 pm
What, me no. No brilliant parody here. You will have to go upthread for that. Or read Enneagram’s posts about “taking mistakes up to galactic levels” and untangling epistemological tangles (to acheive such a bliss).
Or maybe you could go over here.
http://www.cartoonsbyjosh.com/page2.html
Zeke
Leif Svalgaard says:
August 17, 2010 at 9:02 pm
tallbloke says:
August 17, 2010 at 1:21 pm
Hey, our hypothesis is a good deal older and better developed than your new one
Mine is not new and is developed on a viable physics basis.
Clearly not so, since the theory just fell off the end of its non-existent conveyor belt into the dustbin of history. Our theory is based on well know orbital mechanics rather than unproven and now falsified suppositions about the sun’s interior.
You have made no predictions at all,
That’s an untruth. I made a prediction of 50-55 SSN (that’s sun-spots not sun-specks) on your CA blog page over 18 months ago, and it is doing fine.
I have made a [so far] good prediction of the small cycle.
It’s true that the dynamolgers had the situation well covered, with predictions ranging fro the biggest cycle ever (Dikpati) to the smallest cycle ever (Petit?). The ‘mainstream consensus’ went for the big cycle. You were a notable exception.
I have modified Roy Martin’s calculations to test for an electromagnetic influence rather than tidal and the correlation has got MUCH better.
What can be MUCH better than an ‘amazing correlation that leaves no doubt?
Resorting to twisting my words already Leif? I said it was an amazing analysis and that in my opinion it leaves no doubt that there is a link between planetary motion and the solar cycle.
fred houpt says:
August 17, 2010 at 7:08 pm
Having been convinced by the plasma guys
Leif responds:
You have been taken for a ride.
At least he wasn’t taken for a ride on a non-existent conveyor belt.
tallbloke says:
August 17, 2010 at 10:25 pm
“Mine is not new and is developed on a viable physics basis.”
Clearly not so, since the theory just fell off the end of its non-existent conveyor belt into the dustbin of history.
Get your facts straight. I do not work with conveyor belt, but with diffusion and/or a shallow dynamo. The big difference is the memory of the cycle: a few years [me] or a few cycles [Dikpati]. Don’t conflate [and certainly not deliberately the two].
“You have made no predictions at all”
That’s an untruth. I made a prediction on our CA blog page over 18 mnths ago, and it is doing fine
Everybody would do this at the time when it was clear which way the wind was blowing. Mine was almost six years ago. That is a prediction.
I have made a [so far] good prediction of the small cycle.
You were a notable exception.
Because I know what I’m talking about. You may want to refresh your memory on this: http://www.leif.org/research/Predicting%20the%20Solar%20Cycle%20(SORCE%202010).pdf
Resorting to twisting my words already Leif? I said it was an amazing analysis and that in my opinion it leaves no doubt that there is a link between planetary motion and the solar cycle.
And you say now that you have a MUCH better correlation than the one that was ‘amazing’.
Leif Svalgaard says:
August 17, 2010 at 10:36 pm
I do not work with conveyor belt, but with diffusion and/or a shallow dynamo. The big difference is the memory of the cycle: a few years [me] or a few cycles [Dikpati].
Thanks for the clarification. So your method is able to predict “a few years” ahead. What is the “viable physics” basis for the relationship between the solar polar fields you base your predictions on and the production of energy in the sun please? Have you modeled this?
“You have made no predictions at all”
That’s an untruth. I made a prediction on your CA blog page over 18 mnths ago, and it is doing fine
Everybody would do this at the time when it was clear which way the wind was blowing. Mine was almost six years ago. That is a prediction.
“Which way the wind was blowing”? What wind? The solar wind? The wind of change where people realised the planetary theorists are onto something with their observations? Certainly nothing to do with ‘business as usual’ mainstream solar physics from NASA, Hathaway and Dikpati. In 1988 Theodor L predicted a collapse in solar activity to occur after the cycle following the 1993 conjunction of Neptune and Uranus. OK, he was one cycle out, but he was still broadly correct in his analysis of the effect of planetary alignments on solar activity. You certainly did a lot better than Dikpati or Hathaway and I give you credit for that.
Resorting to twisting my words already Leif? I said it was an amazing analysis and that in my opinion it leaves no doubt that there is a link between planetary motion and the solar cycle.
And you say now that you have a MUCH better correlation than the one that was ‘amazing’.
You can’t read my words straight even when they are right in front of you can you? I’ve bolded what I said to help you out.
The correlation Roy Martin worked on involved the assumption of the predominance of a tidal effect of the planets on the Sun. The correlation I have plotted matches the minima MUCH better, and leads me to think the mechanism affecting the timing and shape of the solar cycle is predominantly an electromagnetic effect produced on the solar surface and induced by the planetary alignment positions taking into account the curvature of the interplanetary magnetic field. This does not require large amount of energy to pass from the planets to the solar surface to be effective. I would like to see some data on the path followed by ‘flux ropes’ out into the IMF if you know of any.
The overall amplitude of the cycles is I think affected predominantly by another mechanism, possibly related to the up and down motion of the sun relative to the gas giants. Jupiter, being the biggest planet in the middle of the system is part of both mechanisms. You believe the whole Sun is perfectly in freefall all the time. I don’t. Let’s just agree to disagree about that for now rather than debate the difference between idealised Newtonian mechanics and reality.
I’ll be putting the preliminary result for the first mechanism up on my site later today.
tallbloke says:
August 18, 2010 at 12:12 am
Thanks for the clarification. So your method is able to predict “a few years” ahead. What is the “viable physics” basis for the relationship between the solar polar fields you base your predictions on and the production of energy in the sun please? Have you modeled this?
It is the ‘induction equation’. The model is described nicely by Choudhuri and colleagues: http://www.physics.iisc.ernet.in/~arnab/prl.pdf
“Which way the wind was blowing”? What wind?
If SC24 were to be large it should have shown up strongly back in 2006 and 2007. That it didn’t was a strong indication that the next cycle would be weak and the sunspot prediction panel began to receive low predictions in increasing numbers as people began to realize that perhaps SC24 would be small. Also the ~100 year wave seemed to indicate low activity coming [my grandson figured that out by looking at http://sidc.oma.be/images/wolfaml_small.png ]. And Schatten [using basically my method] had already said:
Solar Activity Heading for a Maunder Minimum? Schatten, K. H.; Tobiska, W. K.
American Astronomical Society, SPD meeting #34, #06.03; Bulletin of the American Astronomical Society, Vol. 35, p.817, May 2003
Abstract
Long-range (few years to decades) solar activity prediction techniques vary greatly in their methods. They range from examining planetary orbits, to spectral analyses (e.g. Fourier, wavelet and spectral analyses), to artificial intelligence methods, to simply using general statistical techniques. Rather than concentrate on statistical/mathematical/numerical methods, we discuss a class of methods which appears to have a “physical basis.” Not only does it have a physical basis, but this basis is rooted in both “basic” physics (dynamo theory), but also solar physics (Babcock dynamo theory). The class we discuss is referred to as “precursor methods,” originally developed by Ohl, Brown and Williams and others, using geomagnetic observations.
My colleagues and I have developed some understanding for how these methods work and have expanded the prediction methods using “solar dynamo precursor” methods, notably a “SODA” index (SOlar Dynamo Amplitude). These methods are now based upon an understanding of the Sun’s dynamo processes- to explain a connection between how the Sun’s fields are generated and how the Sun broadcasts its future activity levels to Earth. This has led to better monitoring of the Sun’s dynamo fields and is leading to more accurate prediction techniques. Related to the Sun’s polar and toroidal magnetic fields, we explain how these methods work, past predictions, the current cycle, and predictions of future of solar activity levels for the next few solar cycles.
The surprising result of these long-range predictions is a rapid decline in solar activity, starting with cycle #24. If this trend continues, we may see the Sun heading towards a “Maunder” type of solar activity minimum – an extensive period of reduced levels of solar activity. For the solar physicists, who enjoy studying solar activity, we hope this isn’t so, but for NASA, which must place and maintain satellites in low earth orbit (LEO), it may help with reboost problems. Space debris, and other aspects of objects in LEO will also be affected.
I would like to see some data on the path followed by ‘flux ropes’ out into the IMF if you know of any.
Flux ropes [as everything else] propagate radially outwards. The Sun keeps rotating, so the place on the Sun where the rope is rooted keeps moving so the rope gets ‘wound up’ around the Sun. In the outer solar system where the large planets are, the rope has been wrapped around the sun several times.
You believe the whole Sun is perfectly in freefall all the time. I don’t.
Newton and Einstein and every physicist in the world agree on this, you don’t. Fair enough, we can disagree. There are people who claim they have been raped by aliens, I disagree with them too.
Leif Svalgaard says:
August 18, 2010 at 1:09 am
tallbloke says:
August 18, 2010 at 12:12 am
I would like to see some data on the path followed by ‘flux ropes’ out into the IMF if you know of any.
Flux ropes [as everything else] propagate radially outwards. The Sun keeps rotating, so the place on the Sun where the rope is rooted keeps moving so the rope gets ‘wound up’ around the Sun. In the outer solar system where the large planets are, the rope has been wrapped around the sun several times.
Excellent! That confirms my approximation thanks. At the orbit of Jupiter with an average solar wind speed the IMF has curved around a lot less than a whole revolution though.
You believe the whole Sun is perfectly in freefall all the time. I don’t.
Newton and Einstein and every physicist in the world agree on this, you don’t. Fair enough, we can disagree. There are people who claim they have been raped by aliens, I disagree with them too.
Some ‘mainstream Climatologists’ liken those who disagree with them to holocaust deniers. You, as a ‘mainstream solar physicist’ liken people who disagree with you to those who claim to have been raped by aliens.
You are at a similar level to them. Down in the gutter.
Newton himself knew his equations of motion don’t apply to highly mobile fluid bodies like the Sun. That’s why he specified ‘inelastic’ in his descriptions of his laws of motion as applied to massive objects. If he were here he would wince with embarassment at your perversion of his theory.
Get thee to a library.
tallbloke says:
August 18, 2010 at 1:32 am
Excellent! That confirms my approximation thanks.
How is that? it means thatit doesn’t matter where the planets are, everywhere they look back at the sun, they’ll see a flux tube, or conversely a flux tube will always have a planet outside so it doesn’t matter where the planet is.
“You believe the whole Sun is perfectly in freefall all the time. I don’t.”
You missed this bit: Newton and Einstein and every physicist in the world agree on this.
You liken people who disagree with you to those who claim to have been raped by aliens.
In this particular case, yes.
You are at a similar level to them. Down in the gutter.
Newton himself knew his equations of motion don’t apply to highly mobile fluid bodies. […] Get thee to a library.
Better, supply a link. Newton’s laws are universal.
[REPLY – But she told me she was over 8654323! ~ Evan]
http://tallbloke.files.wordpress.com/2010/07/ecimf_1.png
Curvature at the orbit of Jupiter will be somewhere in the region of 60 degrees from the radial. I’ll work it out more accurately when I have some time. Sunspots move more slowly around the sun than its average rotation rate don’t they Leif?
tallbloke says:
August 18, 2010 at 1:56 am
Curvature at the orbit of Jupiter will be somewhere in the region of 60 degrees from the radial.
Much larger. Close to 88 degrees.
Sunspots move more slowly around the sun than its average rotation rate don’t they Leif?
No, generally not. You have not specified what ‘average’ means. The correct answer depends on what you mean.
tallbloke says:
August 18, 2010 at 1:56 am
Curvature at the orbit of Jupiter will be somewhere in the region of 60 degrees from the radial.
Much larger. Close to 78 degrees. [sorry for the typo].
At Saturn, about 84 degrees.
Leif Svalgaard says:
August 18, 2010 at 1:42 am
tallbloke says:
Some mainstream climatologists liken those who disagree with them to holocaust deniers. You liken people who disagree with you to those who claim to have been raped by aliens.
In this particular case, yes.
The height of your horse is only matched by the depths you’ll stoop to.
tallbloke says:
“You believe the whole Sun is perfectly in freefall all the time. I don’t.”
You missed this bit: Newton and Einstein and every physicist in the world agree on this.
As I said, Newton himself knew his equations of motion don’t apply to highly mobile fluid bodies like the Sun. That’s why he specified ‘inelastic’ in his descriptions of his laws of motion as applied to massive objects. If he were here he would wince with embarassment at your perversion of his theory. You can’t and won’t answer this point, which is why you try to drive the argument into the gutter instead.
Better, supply a link. Newton’s laws are universal.
Yes, they universally apply to inelastic bodies, as he stated, not objects like the Sun. It’s surprising people so clever in some respects are so stupid in others. The effect of specialisation I suppose. Bet you can’t point to any relativistic proof that the sun behaves as an inelastic body either.
Leif Svalgaard says:
August 18, 2010 at 2:36 am
tallbloke says:
August 18, 2010 at 1:56 am
Curvature at the orbit of Jupiter will be somewhere in the region of 60 degrees from the radial.
Much larger. Close to 78 degrees. [sorry for the typo].
At Saturn, about 84 degrees.
Thanks, I’ll double check when I do the calcs. I also need to calculate how much difference in angle there is between low and high solar wind speeds. I think this will tighten up the looser parts of the synchrony between JEV alignments and the solar cycle timings.
The preliminary plot (uncorrected for solar windspeed variation) is up at:
http://tallbloke.wordpress.com/2010/08/11/roy-martin-venus-earth-jupiter-solar-cycle-analysis/#comment-1951
tallbloke says:
August 17, 2010 at 12:04 pm
Leif Svalgaard says:
August 17, 2010 at 6:59 am
there does not seem to be a conveyor belt at all, but rather several cells, both in latitude and more importantly at depth. What we observe at the surface does not seem to reflect very well what goes on deep within the Sun. SDO will in the coming years tell us more about the circulation(s).
Good luck with the two day old hypothesis on “cells at various depths” Leif. Sincerely, it’s great to see you sweeping away the old and getting on with the new.
~~~
Wasn’t there recently a simular such proposal for the Earth’s dyanamo upon finding cells? hmm have to find that article.
“Californication,” best thing Red Hot Chili Peppers ever did.
Leif Svalgaard says:
August 18, 2010 at 2:22 am (Edit)
tallbloke says:
August 18, 2010 at 1:56 am
Sunspots move more slowly around the sun than its average rotation rate don’t they Leif?
No, generally not. You have not specified what ‘average’ means. The correct answer depends on what you mean.
The average rotation rate at the latitude the sunspot is at.
tallbloke says:
August 18, 2010 at 5:29 am
As I said, Newton himself knew his equations of motion don’t apply to highly mobile fluid bodies like the Sun.
Yet gravity works to keep the gaseous Jupiter in orbit around the gaseous Sun. Gravity from the Moon and the fluid Sun raises the tides in the fluid oceans. Please, Newton’s laws are valid for all bodies.
tallbloke says:
August 18, 2010 at 6:02 am
The average rotation rate at the latitude the sunspot is at.
Presumably then also at the surface [it varies with depth]. We can measure rotation rates in two ways: 1) follow the spot across the disk in which case there is no difference, or 2) using the Doppler shift. Earlier measurements gave an indication that the Doppler rate was very slightly different [a few percent]. Our measurements at Stanford http://www.leif.org/research/Rotation%20of%20the%20Sun.pdf showed that there is no such difference to within 1%. In any event, for anything magnetic the sunspot rate would be the one to use.
The observers at Mt Wilson still maintain [ http://iopscience.iop.org/1538-4357/465/1/L65/5053.text.html ] that the plasma rotates 2% slower than the magnetic field. The usual explanation for the discrepancy is that while the Doppler techniques measure the velocity at the surface, the tracers such as sunspots are anchored in a faster-rotating layer deeper down. But to within 2% one can say there is no difference.