Usually, and that means in the past year, when you look at the false color MDI image from SOHO, you can look at the corresponding magnetogram and see some sort of disturbance going on, even it it is not visible as a sunspot, sunspeck, or plage area.
Not today.
Left: SOHO MDI “visible” image Right: SOHO Magnetogram
Click for larger image
Wherefore art though, cycle 24?
In contrast, September 28th, 2001
“the sun has an internal oscillation period of around 10.5 years, and the motion of the planets above and below the solar equator create harmonic resonances which ‘ring the sun’s bell’ and amplify or dampen the effect, modulating it to the varying length and amplitude solar cycles we see in the sunspot record. ”
Very interesting, and within scope for engineers! In the course of DiffEq one studies harmonic resonances with simple 2nd order linear differential equations.
We had one short movie in the course, a galloping suspension bridge! As I remember an old model A or similar vintage car was stopped halfway and disappeared for much of the time as the waves(both in the direction of the bridge and transverse) were much larger in amplitude.
The wind speed at the time of the film escapes me.
Already spotted one error… that 10pi, 11pi, etc. ought to be 2piR (or piD) so it would be 20pi, 22pi, etc.
Did I mention that I didn’t like angular momentum physics in school?… 😎
Robert Bateman (09:57:24) :
Leif Svalgaard (10:17:19) :
Ok, maybe I misinterpreted the answer. The internet makes it hard to sort sarcastic comments from a simple answer. It seemed at first like a sarcastic, go look for yourself kind of answer. Apology.
Is there somewhere one can look at the sun’s fluctuations in size?
David Reese:“If one moves a current within a magnetic field, forces are involved, hence a couple! Immense electromagnetic disturbance can be caused by planets pulling the sun in different directions”
The trouble is that we, as observers of just an “instant solar system” can not but imagine what would it be if our “blinking of an eye” would be, say, 30000 years long; we would be arguing about not about spheres (or worst, round pebbles in the sky) but about helicoidals, perhaps resembling a Ruhmkorff coil.
David Reese (10:29:56) :
Leif, there is a force that moves the electrical currents. It is the gravitation force of the planets which move the sun about it’s barycenter.
They move the whole Sun and not just a piece of it. It is like moving a battery-powered flashlight. Do you think that you get more light from it if you wave it vigorously?
E.M.Smith (10:34:06) :
At this point, the center of the planet is traveling a distance of 10pi in one time period (orbit) while the outer edge is travling 11pi and the inner edge is traveling 9pi per unit of time.
Gravity and ‘orbital forces’ work as if all the mass was concentrated at the center of gravity. This was a fundamental result first derived by Isaac Newton.
Here is more on forces, center of gravity, torques, and lever arms:
http://www.valdosta.edu/~pbaskin/phys1111ch9notes.doc
And this has nothing to do with the Sun being fluid [people often think that that is somehow important]. There are small deviations form the ‘center of gravity’ principle and these are called ‘tides’ stemming from the fact that the gravitational force is different from one side of the body to the other side. On the Sun these are VERY small.
gary gulrud (10:46:49) :
“the sun has an internal oscillation period of around 10.5 years
I missed where you got this ‘tidbit’ from?
Ohioholic (10:55:33) :
Robert Bateman (09:57:24) :
Leif Svalgaard (10:17:19) :
Ok, maybe I misinterpreted the answer. The internet makes it hard to sort sarcastic comments
You and other can rest assured that I would never do a thing like that. I may say that something is nonsense if I think it is, but that is not meant sarcastically.
Is there somewhere one can look at the sun’s fluctuations in size?
Basically no, at the present time.
anna v (04:47:46) :
1)The only viable coupling in the solar system, i.e. with some energy to create tides, is gravity. The effect of the planets on the sun is tiny tides, of the order of milimeters.
I would assert that you only need conservation of angular momentum, not tides, to influence the solar spin.
( barycenter movement is irrelevant and a red herring, one needs forces).
I would further assert that barycenter movement is relevant since, as the center of orbit, it determines the length of the position vector in the ( p x r ) calculation of orbital angular momentum.
As the position vector approaches zero: p x r approaches zero and that angular momentum must be conserved and must go somewhere with solar spin being a prime candidate (and maybe via some kind of orbital resonance? into planetary orbit / spin changes).
Adolfo Giurfa: Have you found my misplaced Spirograph. I like to think of our Solar System’s Journey as a Symphony replete with many Harmonics.
Leif Svalgaard (08:48:07) :
The tiny solar cycle variation we expect does not rise enough over the noise to be visible. For a 300-year series the noise on the average [or on an FFT peak] would be of the order of the standard deviation divided by the square root of 300 i.e. ~18. The standard deviation [variation from year to year] is certainly larger than a degree, hence the noise would be larger than 1/18 = 0.06 degrees, so no wonder that the TSI signal does not show.
Leif,
What do you think it is I’ve been showing? In my last post, I presented two MTM spectrum analyses, one for global temperature data, and the other for a regional data set for the US Southern Region. Both show spectra that are statistically significant (i.e. rise above the noise) at frequencies that could plausibly be related to the solar cycle.
But ignore that (since that is what you are doing), for a moment. Let’s do your exercise with my data for the US Central Region (previously I miswrote “Southern” Region; I’ve got data on all 9 regional divisions I’m studying). I’ve got a little over a hundred years of monthly observations for this data series, 1356 to be exact. The standard deviation is 0.64875. That s.d. divided by the square root of 1356 is 0.0176. The units are in Centigrade. You’ve said TSI can account for absolute range of about 0.07, which is about twice this (2×0.0176 = ~ 0.035). So there is no reason to close your mind to the possibility of being able to see this signal above the background.
And that’s what you see here, in an MTM spectrum analysis of this particular data series:
http://s5.tinypic.com/r1adtl.jpg
And the time domain representation here:
http://s5.tinypic.com/hreogj.jpg
Now let’s back away from this for a minute. I don’t know that solar is “the” cause of the spectra you see in the preceding graphs. What I know are that (a) we are looking at something that cannot be dismissed as “lost in the noise,” (b) the magnitude of variation is within the range of what could be attributed to TSI, and (c) the spectra are of a frequency that could be attributed to the solar cycle.
Previously you’ve said that you would “expect” to see this. Then you come along and say that you don’t expect to see it because it is not “visible” above the background noise.
You are a hard person to dialog with, even on the best of terms, sometimes.
Leif, if you drop a copper penny into a strong magnetic field, the penny slows down dramatically. While it is moving in the field, electrical currents are induced that produce a force that opposes the force of gravity. The penny will resume the acceleration of gravity as it leaves the field.
Does temp fluctuation on the surface of the Sun, combined with our exposure to hot spots due to orbit, make a difference at all? I have no idea how many times during one orbit we are exposed to the same specific spot on the sun, and if it is a hot spot, what difference that would make. Just as example figures to try and illustrate what I am asking about, as I am having a hard time putting it into words, if we are exposed to a hot spot 75% of the time, and a cold spot 25%, and then in our next orbit the opposite, would this make a difference?
@Leif Svalgaard (11:15:01) : Here is more on forces, center of gravity, torques,
Thanks, I’ve downloaded it and will proceed to read…
But I’m still waiting for the answer to the question: As the position vector approaches zero, where does the angular momentum go to be conserved?…
Conservation of Angular momentum: It’s not just a good idea, it’s the law.
Position Vector approaches zero as barycenter approaches solar center (and this is known to happen, not a hypothetical.)
Position Vector near zero says L=r x p near zero. Physics, by definition.
Angular momentum was conserved.
Where did it go?
E.M.Smith (11:49:17) : Angular momentum was conserved.
Where did it go?
I probably ought to add to that:
From kohai, nervously eyeing his usual spot on the foor 8-0 !
(I do feel almost exactly like I did as a lowly purple belt asking 4th? degree black belt Sensei “What happens if I did This? ” — hello floor… )
Solar magnetic fields (polar and sunspots) change polarity along the solar cycles’ progression (with half a cycle phase shift).
One way this can be achieved is through the flow of ‘solar currents’, modulated by a feedback through energy interchange between solar wind and the planetary magnetospheres.
The intensity of the feedback may also be a function of planetary position within heliosphere’s geometry.
http://www.geocities.com/vukcevicu/SolarCurrents.gif
http://www.vukcevic.co.uk/combined.gif
http://www.vukcevic.co.uk/PolarFields-vf.gif
http://www.vukcevic.co.uk/ solar current link
Leif,
” Do you think that you get more light from it if you wave it vigorously?”
if it has an inductive set up to recharge the batteries in it I DO!!!!
HAHAHAHAHA
Leif Svalgaard (08:48:07) :
“Our polar field method only predicts the size and not the timing. The 2011 time frame is a ‘nomimal’ time just adding 11 years to the 2000 maximum time [BTW, the referee’s wouldn’t let us speculate on the timing, pointing out (correctly, we conceded) that the polar field precursor method does not provide a timing prediction in itself]. So, this was not a prediction.”
“we predict that the approaching solar cycle 24 (~2011 maximum) will have a peak smoothed monthly sunspot number of 75 +/- 8”
http://adsabs.harvard.edu/abs/2005GeoRL..3201104S
This clearly looks like a prediction and “speculating”. Treat it as not being formally a prediction if you wish, but I find your claim that the reviewers would not let you speculate on the timing, yet allow the speculation to occur in the prediction itself, but only based on a “generic” 11 year cycle. If that it were true there would have been absolutely no reason to approximate timing of the maximum, *especially* if you knew then what you claim now. In any event my question remains unanswered. If you knew then that a small cycle would take longer to appear from minimum and be slower to ramp up to maximum than a larger cycle, in your words the sun would be doing “just what it should be”, why did you approximate SC24 maximum in 2011, in your 2005 prediction above?
E.M.Smith (11:26:04) :
“anna v (04:47:46) :
1)The only viable coupling in the solar system, i.e. with some energy to create tides, is gravity. The effect of the planets on the sun is tiny tides, of the order of milimeters.”
I would assert that you only need conservation of angular momentum, not tides, to influence the solar spin.
Conservation of angular momentum of a spinning object means it will keep on spinning at the same angular velocity, unless something interferes with it. Take a spinning top on ice. Have an ice skater run in a circle around it. You can define an rxp between the spinning top and the skater. So? If the skater stops will the top stop spinning? If a hole opens and eats the spinning top will the skater change angular momentum? There is no interaction between skater and spinning top and that is why it is irrelevant to calculate angular momenta between the two.
It is the forces that define angular momentum changes.
“( barycenter movement is irrelevant and a red herring, one needs forces).”
I would further assert that barycenter movement is relevant since, as the center of orbit, it determines the length of the position vector in the ( p x r ) calculation of orbital angular momentum.
You can always define an angular momentum for moving masses, from an infinity of axis. The point is whether these axis have a relevance to the forces in the problem. The only relevance of the orbiting of the sun about the barycenter comes from the gravitational interaction with all the planets and the balance of orbital angular momenta is with the total solar system ( when the sun’s increases, Jupiter etc decreases, usw). It is all a matter of coordinate systems. The individual planetary and sun spins about their axis are conserved, except for the small effect of gravity with the tidal forces.
As the position vector approaches zero: p x r approaches zero and that angular momentum must be conserved and must go somewhere with solar spin being a prime candidate (and maybe via some kind of orbital resonance? into planetary orbit / spin changes).
By construction, the barycenter does not pass through the center of the sun. The changes of the orbital angular momentum you are envisioning are taken up by the whole solar system. As with earth/moon, so with the sun, even if the barycenter goes through a part of it, nothing happens since the barycenter has no mass.
Ninderthana (15:41:21) :
captdallas2,
“Has it ever occured to you that the undrelying mechanism that drives the PDO
may be indirectly linked a mechanism that drives solar activity?”
Have do done any supplemental linkage work with 10Be and 14C records that are associated with solar activity or are these proxies irrelevant to your study?
What drives what is the mystery. I am not particularly impressed with the quality of proxy reconstructions or the quality of most models. They are only predictive is things don’t change. Things change in climate and finance. Don’t put your retirement plans in models or you will work for the rest of your life.
Here are my thoughts:
All proxies should be viewed with great skepticism.
Trees are not thermometers.
It ain’t the sun, at least for now.
While climate is complex that don’t mean it can’t be predicted. The error bars may be large, but there are things that are predictable.
So for the next twenty to twenty five years we should see a slight cooling trend. It could be a flat trend, but odds are we will have some cooling. That doesn’t mean that there may be a high or low spike year, just that the trend should be neutral or cooler. Why? Because temperatures have been higher than normal. The Earth is a huge buffer. Oceans, atmosphere and ice all seek a mean climate. They will change to seek that mean
Does that mean there is no anthropogenic induced climate change? No, it just means that it is harder to decipher how much may be anthropogenic.
My money is on 1 degree C for co2 doubling. The water vapor feedback numbers don’t seem to add up so Hansen’s 4 degrees seems to be irrational. Actually, Hansen often seems irrational.
There is just more to the story than pick a pet theory. It is chaotic.
@ur momisugly anna v (12:48:39) :
Thank you for the response. It does seem to me to still ‘skip over’ some bits that I think can not be skipped…
Conservation of angular momentum of a spinning object means it will keep on spinning at the same angular velocity, unless something interferes with it.
I was talking about the angular momentum of the orbit, not the spin, in this first part. That as the orbit about the center of rotation (the definition of the barycenter) approaches zero, the orbital angular momentum position vector (distance from center of rotation and change of radians per unit time) must drop approaching zero. In that case the cross product with linear momentum will approach zero. Where does the angular momentum go? It’s a later assertion that it might go into spin…
( barycenter movement is irrelevant and a red herring, one needs forces).
You can always define an angular momentum for moving masses, from an infinity of axis. The point is whether these axis have a relevance to the forces in the problem.
Is it not the case that the definition of barycenter is that it is the center of mass about which objects in the solar system rotate in their orbits? Is that not the only place the sun is orbiting? I can see no rationale for putting the solar center of orbit vector on, for example, the moon… All it would do is make the math very very messy, but at the end of the day, the distance for solar center to center of orbit changes and that changes orbital angular momentum.
If it is, in fact, the correct root for the solar position vector in L=r x p then we must admit that the length of the position vector changes (up to 2 x solar radii outside the sun center, and sometimes crossing right near the center of the sun, during the “retrograde” part of the orbit approaching zero.
The only relevance of the orbiting of the sun about the barycenter comes from the gravitational interaction with all the planets and the balance of orbital angular momenta is with the total solar system ( when the sun’s increases, Jupiter etc decreases, usw).
And that’s the whole point. The angular momentum is going somewhere… and there is spin orbit coupling; certainly at the subatomic level and from what I can find, accepted at the planetary level, so I don’t see how we can just say to ignore it without knowing how to calculate how much and why…
It is all a matter of coordinate systems. The individual planetary and sun spins about their axis are conserved, except for the small effect of gravity with the tidal forces.
That is an assertion, not a solution of the physics. As L=r x p has the position vector approach zero (use zero, or use 1/10th if you don’t want to accept that it could actually reach zero; it doesn’t change the problem…) the angular momentum attributable to the orbit about the center of the orbit approaches zero (or 1/10th, again, it doesn’t change the final question).
Angular momentum must be conserved. Where did it go if not into spin? If it went off to Jupiter, how did it get there? When it got to Jupiter, why would it show up as orbit, with zero as spin (given that spin orbit coupling seems well attested as a part of physics.)
By construction, the barycenter does not pass through the center of the sun. The changes of the orbital angular momentum you are envisioning are taken up by the whole solar system.
I don’t really care if the center of orbit ever crosses exactly through the zero point. We know that it ranges from 2 x solar radii away from the center of mass of the sun, down to at least 1/10th of a solar radius in 1990-91 darned near the exact center of the sun (when, IIRC, it snowed here abnormally…) This means we know that the position vector approaches zero, which still leaves us with the problem. Where does the angular momentum go?
You again assert that it goes into ‘the whole solar system’. What bit of physics sorts it between solar spin angular momentum, planetary orbital angular momentum, planetary spin angular momentum, {else clause}?
I’ve made a “thought experiment” that looks to me like a reasonable way to convert orbital momentum into spin momentum (without tides). I see no reason to just wave away the angular momentum to a vague somewhere else. (Now, I could just be blind, but i don’t think so…)
Sidebar: Mr. McGuire, as physics teacher… He had a turntable students could stand on. He would hand us a bike wheel on a spindle, then spin it up and spin us up, and we would move the wheel. Strange things happened. Now, unfortunately it was about 40 years ago so memories are getting dodgy… but I would swear that one of the things we went over was exactly that thought experiment and that as the wheel was brought closer to the person, both the person and the wheel changed spin… I would love to find such a table on bearings and wheel with handles again…
As with earth/moon, so with the sun, even if the barycenter goes through a part of it, nothing happens since the barycenter has no mass.
You are again implying that my question wants the barycenter to have a force, a mass, or something physical. I specifically disclaim any such assertion. It has no mass. It has no gravity. It has NOTHING physical. I get it.
But what it does have is a definition. By definition it is the center of orbit. By definition, it is where the solar orbit position vector ends. By definition, as the distance of the barycenter from the solar center changes, the solar orbital position vector changes. When then, again by definition, L= r x p says the orbital angular momentum changes.
So where does the angular momentum go? And what does it do when it gets there? And how do you know? What formula is used?
“There is just more to the story than pick a pet theory. It is chaotic.”
Hence the skepticism of global warming, yes?
gary gulrud (10:46:49) :
That was a bridge (“Galloping Gerdy” (sp?)) across the Tacoma Narrows at the southern tip of Puget Sound in Washington State. As I understand it, the wind was something like 70 mph. The problem was that the bridge deck was behaving like an airplane wing and one side would want to lift. But because it was constrained, that lifting force could not be sustained and the bridge would need to return to its original position but would overshoot. There was a periodicity to this forcing and it happened to coincide with a natural harmonic structural vibration frequency of the bridge which “magnified” the effect. I don’t know if there were further special circumstances required. Did the wind need to be within a small band of direction and speed for the forcing to continue, or was the bridge susceptible to a fairly broad range? BTW, I believe it got its name before it broke apart.
Perhaps the sun spots and our ocean cycles are galloping like Gerdy.
Ohioholic (14:25:32) : said:
“There is just more to the story than pick a pet theory. It is chaotic.”
Hence the skepticism of global warming, yes?
Exactly. Don’t get me wrong, I am not the sharpest tack in the box. I am fairly intelligent and a devote skeptic of everything. Some of the climatological stuff makes sense and some I find asinine. Eric Steig’s Antarctic study I feel is asinine because the potential error is so large it is a coin toss. His abstract should have said the antarctic may or may not be warming. I don’t know which.
Micheal Mann’s affection for tree rings is just that, a warm and fuzzy emotional feeling. His science sucks or he would have compared updated versions of the records he used. He is an egomaniacal idiot. Just my personal opinion Anthony, don’t mean to be offensive, but if the shoe fits.
So there is a lot of stuff to be skeptical of. The sun though, by itself, is a red herring that detracts from the advancement of the debate. Proxy reconstructions are cited by both sides without consideration of their validity. Why outdated proxies are cited is beyond me, stupidity, politics, who knows. People do need to get up to speed if they want to learn the truth.
Basil (11:31:58) :
…I’ve got a little over a hundred years of monthly observations for this data series, 1356 to be exact. …
And that’s what you see here, in an MTM spectrum analysis of this particular data series:
Hello basil – do you have a source of this data that I can access please?
Not sure how the harmonics are displayed using the ssa mtm programme so I would like to try using excel!!!
Basil (11:31:58) :
…I’ve got a little over a hundred years of monthly observations for this data series, 1356 to be exact. …
And that’s what you see here, in an MTM spectrum analysis of this particular data series:
Hello basil – do you have a source of this data that I can access please?
Not sure how the harmonics are displayed using the ssa mtm programme so I would like to try using excel!!! I assume the prog reconstructs the black harmonics ?
If the centre of mass of the sun is orbting around the (moving) barycentre of the solar system, and the interior of the sun is not rigid, it seems reasonable to assume that the internal activity of the sun will be influenced by the dynamics of the gravitational forces involved – doesn’t it?