The sun seems not to be in cooperative mood again this month. It has gone blank again.
And from SWPC, the brief upticks of April were not repeated in May:
More info at the WUWT solar page
The sun seems not to be in cooperative mood again this month. It has gone blank again.
And from SWPC, the brief upticks of April were not repeated in May:
More info at the WUWT solar page
I can’t quite grasp what it is about the reduced magnetic field from the Sun spots causing the decreased rotation. Is it because previous rotations were wound so tight (which would explain all the sunspots of previous cycles) that the whole system is now unwinding, thus slowing down? I am reminded of the process of making rope, which when twisted tight enough and then both ends brought together, immediately coils around itself and then transitions to a relaxed yet still twisted state with no more rotational movement, or the slightly different process of the twisting of a child’s swing till it can twist no more, then when released, unwinds to it’s original resting state so to speak. The physics of making rope and the physics of twisting a swing (again, two different processes but both ending in a rested state) I can understand. Is it similar?
According to the known laws of physics there is no such transfer. Shirley [who is a strong believer in planetary influence] has shown that so clearly: http://www.leif.org/research/Spin-Orbit-Coupling-Shirley-JPL.pdf
The paper considers the sun in free fall. The sun is not in free fall. As it both rotates and orbits the barycenter, the gravitational forces on individual particles within the sun change as they move closer to, and away from the barycenter. While the mass of the sun remains constant, the weight of different portions of the sun is constantly changing. The effect being maximized as the sun moves away from the barycenter.
So, for example, when the barycenter coincides with the center of the sun, a particle at the center will be weightless. But as the barycenter moves away from the center this same particle will now have weight in the direction of the barycenter and will try and move in that direction. When this happens to a particle that is not at the exact center of the sun, it will try and move in relation to the center, which is the torque missing in the above reference paper.
lgl says:
June 19, 2011 at 6:13 am
After you have defined what is real physics.
Real physics is the corpus of knowledge that is encoded in three sets of physical ‘laws’
Maxwell’s equations, Einstein’s special and general relativity [and the still good enough for most purposes Newtonian predecessor], and Quantum Mechanics. For the problem at hand Maxwell and Newton suffice.
Pamela Gray says:
June 19, 2011 at 6:18 am
I can’t quite grasp what it is about the reduced magnetic field from the Sun spots causing the decreased rotation.
It is the other way around. The stronger magnetic field [or actually just more of it, i.e. many sunspots] slows down the rotation at the lower latitudes [8 to 30 degrees] where the spots are. Brun explains how it works: http://lcd-www.colorado.edu/sabrun/StellarConvection_26April08.pdf
ferd berple says:
June 19, 2011 at 8:01 am
The paper considers the sun in free fall. The sun is not in free fall.
Free fall means that a body is moving solely under the influences of gravity [for the Sun that includes the combined gravitational influence from all the planets and beyond].
But as the barycenter moves away from the center this same particle will now have weight in the direction of the barycenter and will try and move in that direction.
The Earth and the Moon also move around their common barycenter, which since the Moon’s orbit is quite eccentric would mean in your view that my weight should vary with the lunar distance. No such change in weight occurs [we can measure my weight with a spring balance which stiffness would not vary with the lunar distance].
But, please, this has been discussed so many times at WUWT that you might benefit from digging up those discussions, so we don’t have to repeat them for the umpteenth time. The barycenter does have mass and thus do not attract the Sun or different parts of it differently. You can be sure that Shirley knows all of this, even if you don’t.
ferd berple says:
June 19, 2011 at 8:01 am
The barycenter does NOT have mass and thus does not attract the Sun or different parts of it differently.
Sorry for the typo
ferd berple says:
June 19, 2011 at 8:01 am
But as the barycenter moves away from the center this same particle will now have weight in the direction of the barycenter and will try and move in that direction.
Consider two stars with identical masses orbiting each other in a very eccentric orbit [meaning that the orbit is a very elongated ellipse]. The barycenter is always exactly halfway between the two stars. Seen from either star the barycenter moves back and forth a lot as the distance between the stars change. In your view that will now try to move the stars towards each other [“in the direction of the barycenter] especially when the barycenter is at its closest. This will result in the orbits getting smaller and smaller with eventual collapse of the system which does not happen in fact. [Actually it will happen eventually according to General Relativity because the bodies emit gravitational waves that carry energy away from the system. This however for ordinary systems happens so slowly that it cannot be observed. However in some systems the orbits are already so small that gravitation is so strong that the emission of gravitational waves does become noticeable and the two stars are spiraling towards a collision http://www.astro.cornell.edu/academics/courses/astro2201/psr1913.htm – in 300 million years from now for that system]
Leif
The stronger magnetic field [or actually just more of it, i.e. many sunspots] slows down the rotation at the lower latitudes
Here you are saying the rotational cycle is 11 years, not 22 years as stated here http://www.solarstation.ru/TL/PDF/tl_22.pdf fig1 & 3.
lgl says:
June 19, 2011 at 11:12 am
Here you are saying the rotational cycle is 11 years, not 22 years as stated here http://www.solarstation.ru/TL/PDF/tl_22.pdf fig1 & 3.
I’m saying that it is very difficult to determine the rotation rate from the old data. We undertook a very thorough re-analysis of the Greenwich photographic observations 1878-1981 [Fig 1 of http://www.leif.org/research/ast10867.pdf ] and do not confirm the result of the paper you cite. There is no significant 22-yr variation in the data. The only clear signal is a general dependence on solar activity as a whole [Fig. 2], which confirms the predictions by Brun and others. It is generally accepted that magnetic activity near the surface controls the variations of the surface rotation rate.
lgl says:
June 19, 2011 at 11:12 am
Here you are saying the rotational cycle is 11 years
There is an 11-yr substructure in solar rotation. A good indicator for solar rotation is the rotation of the interplanetary field which is dragged out by the solar wind. The IMF is an indicator of large-scale solar rotation. Many years ago we looked carefully at the long-term variation of the rotation:
http://www.leif.org/research/Long-term%20Evolution%20of%20Solar%20Sector%20Structure.pdf
Although I have not formally brought that paper up to day with almost 40 years of new data, I monitor the IMF polarity carefully and continuously. Here is the complete list up to today: http://www.leif.org/research/spolar.txt The newer data shows just the same as the 1975 paper, namely that in every 11-yr cycle we have slightly faster rotation in the first half of the cycle and a slightly slower rotation in the last half of each cycle. In addition, at each solar max, there is a part of the sun that rotates even slower than the rest. There is not 22-yr variation in this.
I would ascribe your picking of papers to confirmation bias: you find the ones you like. How come you didn’t find mine?
Leif
There are more studies finding a 22 year variation so try again. Findings are not myths just because you have not been able to reproduce them.
http://arxiv.org/PS_cache/arxiv/pdf/1103/1103.2869v1.pdf
http://www.springerlink.com/content/234030887517155p/
And yes, I was looking for a 22 years cycle so my search contained “22 years”. Remember to include ” there is no 22 years variation” in your papers so I can find yours too 🙂
lgl says:
June 20, 2011 at 8:17 am
There are more studies finding a 22 year variation so try again. Findings are not myths just because you have not been able to reproduce them. http://www.springerlink.com/content/234030887517155p/
These guys are colleagues of mine. That they find power at 3*11, 2*11, 1*11, 0.5*11, and 0.33*11 simply shows that the fundamental period is 11 years.
Actually a sunspot cycle is not really 11 years. From the time when the first spots of a cycle is born until the last spot of that cycle dies is 17 years, so for many years you have spots from two cycles simultaneously on the disk. No 22-yr cycles there. In any event the real problem is not the 22-yr cycle but the nonphysical sleight of hand of assigning a sign to the cycles.
Leif
Do you know the amplitudes of those 11 yr multiples?
Maybe that 17 years actually is 22 years, just no visible spots the last 5 years. I read somewhere some streams moving from equator to the pol in 22 years.
Reversed polarity means the relative motion of part1and part2 reversed, so a sign is perfectly physical.
lgl says:
I read somewhere some streams moving from equator to the pol in 22 years.
Which means that every solar cycle with have two of those streams [which they actually do]
Reversed polarity means the relative motion of part1and part2 reversed, so a sign is perfectly physical.
Since every cycle has two streams there is nothing that distinguishes one cycle from the next, and both streaming toward the equator [there is also a short polar stream at the beginning of each cycle, but it has no spots]. During part of the life of a stream it has sunspots, at the beginning and end it has no spots. So, for several years, you’ll have on the disk spots that belong to two different cycles, so you must count some of them negative and some of them positive. Do you do that? or just lump them all together? Putting a sign on the cycle is something that crops up now and then. And it is the wrong thing to do every time. But since it is important to you, I figure that any argument or analysis I do will have no effect whatsoever.
Leif
.. there is nothing that distinguishes one cycle from the next except the polarity you mean.
so you must count some of them negative and some of them positive, or as belonging to two different cycles, one ‘positive’ and one ‘negative’ any argument or analysis which explains the reversed polarity will have some effect.