Below I have the latest solar cycle progression the NOAA’s Space Weather Prediction Center.
Sunspots look to be on a course for a peak well below the forecast red line.
The 10.7 centimeter radio flux remains anemic.
And the magnetic personality of the sun (The Ap planetary index) isn’t ramping up, just bumping along.
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Regarding the sun vs solar system barycenter:
When you stand on earth, you are always experiencing the gravitational force. It presses you against earth. When you go by train or fly an aircraft, you still experience it. If you enter the Vomit Comet aircraft and navigate it on its parabolic trajectory, you stop experiencing gravity – you find yourself flying and nothing is exterting any force on you in any direction. You feel like you lost all weight don’t even realize the plane has to accelerate really fast to keep up with you. This does not mean gravity is not acting upon you at that moment – it is, you just don’t experience any forces because every atom of your body is getting the same acceleration in the same direction.
Sun is on Vomit Comet all the time. Yes it goes through complicated epicycles around the solar system barycenter, but it does not experience any forces (except really tiny tidal forces from planets) because its every atom is forced the same direction all the time.
Now, the finding is that there is certain level of correlation between sun’s movement around solar system barycenter and climate changes observed in the past. First of all, the correlation is rather weak. It’s weak enough that there is good chance it’s just accidental similarity rather than causation. Remember the graph of global warming vs US postal service prices. And the fact that our current understanding of universe does not provide us any mechanisms that could be behind this kind of causation just adds to that.
If you wish to believe there is causation, feel free to believe in that. But please don’t take it for granted because no real scientist will grant you it really works until either the correlation is much better or the causation mechanism is known.
Personaly I think it’s just accidental similarity.
rbateman says:
August 10, 2011 at 8:47 am
Way too much space in between stars in the Galaxy, except in the core, and a Galaxy ‘collision’ is a very misleading event. The coherence of two galaxies in “collision” would be tidally disrupted, flinging great quantities of stars about, distort core structures, send shock waves about piling up dust and gas into fronts with new star formation. But, in reality, very few stars would actually strike one another.
Doesn’t matter. Actually, one can say that this is a counter argument against people who claim that the sun is not solid. They forget that tides work best on fluids, gases, and galaxies [the ultimate in non-solid bodies].
The cores of two galaxies could merge, and over millions of mergers one might get 2 supermassive black holes to collide (as in strike each other) and the resultant outcome would be…. don’t think anyone has any math for that.
General relativity describes that precisely, and people have actually calculated the outcomes of that. A ‘scream’ of gravitational waves would result and we are building large detectors hoping to observe such waves [and the ones from smaller black holes as well – http://www.black-holes.org/explore2.html ]
rbateman says:
August 10, 2011 at 8:47 am
Way too much space in between stars in the Galaxy, except in the core, and a Galaxy ‘collision’ is a very misleading event.
Planetary rings [e.g. http://pds-rings.seti.org/saturn/vgr1_iss/PIA00335.html ] were formed by tidal forces tearing apart o moon that got too close. Tidal forces are all over and work on all bodies, dense, dilute, or whatever. Jupiter’s moon Io is ‘kneaded’ by tidal forces and the friction keeps the moon hot and molten, resulting in spectacular sulfur volcanoes http://en.wikipedia.org/wiki/Io_(moon)#Tidal_heating
The only thing that matters for tides due to a mass m at distance d from a body of mass M and radius R, is the dimensionless ‘tidal’ number N = (m/M)(R/d)^3. For Jupiter on the Sun we have N = 7E-13, for the Moon on the Earth, N = 6E-8 or 100,000 times larger. For Io, N = 1.6E-3 or about 30,000 still larger than the Moon’s on the Earth. Tides are very powerful close in, but become very small for large distances.
Leif is right about the Sun being in free-fall about the barycentre. The Sun’s relatively large size with respect to the distance from the Barycentre does not change the fact that all of the particles within the Sun are free-falling towards the Barycentre and therefore feel no external force.
There are two other ways in which the planets can directly effect the convective layer of the Sun
but both a very weak.
I will outline the first idea here and if people want I will put forward a second idea. I realize that both
of my ideas are are only speculative but they may spark someone to come up with an even better idea.
The first idea is to image that you are looking at the Sun from Jupiter, which is slowly moving around the Sun once every 11.86 years. What you see is a torus (or ring) of plasma in the convective layer of the Sun that is slowly rotating compared to the polar regions of the Sun.
This occurs because of the differential rotation of the convective layers of the Sun (The convective layer is roughly about 2 % of the Solar mass and extends from 0.72 R to 1.0 R where R is the radius of the Sun). The convective layer of the Sun between +/- 30 solar latitude takes about 25-26 (say 25.5) days to rotate once, while the polar regions take roughly 34 days. This means that the torus of plasma in the solar “tropics” rotates with respect to the solar poles once every 102 or so days.
This torus of rotating gas, which includes ~ 1 % of the Sun’s total mass, is tilted by ~ 6 degrees with respect to Jupiter’s orbit. and so it experiences a tugging force every ~ 102 days that tries
to pull the rotating torus of plasma upright. However, the tugging force is only very small as it must be proportional to the difference in Jupiter’s gravitational force on the near and far sides of the torus ring (as seen from Jupiter). Like a tidal force, the magnitude of this differential force most likely depends on the distance between Jupiter and the Sun cubed.
Still, this tugging force would cause the torus to begin precessing about the Sun with respect to the rest of the Sun’s more slowly rotating convective layer further away from the “tropics”.
Now, it also possible that a convective torus of plasma may produce its own magnetic axis that is tilted by 6 (+/- 3) degrees compared that of Jupiter’s magnetic pole and there may be a magnetic rather than gravitational tugging on the rotating ring of plasma that is trying to force it upright.
This may provide a strong tugging force that could be causing the torus to precess on timescales
are of the ~ 22 years.
Remember this is only wild speculation at this point.
Ninderthana says:
August 10, 2011 at 9:50 am
Still, this tugging force would cause the torus to begin precessing about the Sun with respect to the rest of the Sun’s more slowly rotating convective layer further away from the “tropics”.
An immediate problem with that [apart from the smallness of that, still, tidal effect] is that solar activity is most likely not generated in the convection zone, but just below it [below the tachocline] or [as some solar physicists speculate] very near the surface, so what happens in the convection zone is not too important. The reason for believing that the solar dynamo works below the convection zone is that material in the convection zone rise quickly [in a matter of weeks] to the surface and that there therefore isn’t enough time for the dynamo to amplify the field.
The peak SSN will be in the 50s, maybe the low 50s. Certainly not the 70s. Notwithstanding all the sub-one-day specks that are being promoted beyond their proper station.
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Leif Svalgaard says:
August 10, 2011 at 6:57 am
SandyInDeby says:
August 10, 2011 at 12:43 am
How do tides in Earth’s seas work then?
Because there is a small difference in gravity from the Moon across the diameter of the Earth. There is also a small difference in gravity from the planets across the diameter of the Sun causing tides less that 1 millimeter in height.
So this wasn’t quite correct?
Leif Svalgaard says:
August 9, 2011 at 10:03 pm
David L. Hagen says:
August 9, 2011 at 9:19 pm
See Ed Fix’s model
Ed Fix says “this system must be driven by an outside force evidenced by the radial acceleration of the sun relative to the barycenter” etc.
As the sun is in free fall it does not feel any forces or accelerations, so the theory fails right there.
Leif Svalgaard says:
August 9, 2011 at 10:03 pm
David L. Hagen says:
August 9, 2011 at 9:19 pm
Note also Ed Fix describes his cycle analysis method at Tallbloke’s blog: Solar activity simulation model revealed.
Ed Fix says “this system must be driven by an outside force evidenced by the radial acceleration of the sun relative to the barycenter”.
As the sun is in free fall it does not feel any forces or accelerations, so the theory fails right there.
Still busy with the gatekeeping duty I see Leif. 🙂
http://tallbloke.wordpress.com/2011/07/25/ed-fix-solar-activity-simulation-model-revealed/
also of interest
http://tallbloke.wordpress.com/2011/08/05/jackpot-jupiter-and-saturn-solar-cycle-link-confirmed/
tallbloke says:
August 10, 2011 at 10:43 am
“As the sun is in free fall it does not feel any forces or accelerations, so the theory fails right there.”
Still busy with the gatekeeping duty I see Leif.
Just countering misinformation as one should.
Brian H says:
August 10, 2011 at 10:39 am
The peak SSN will be in the 50s, maybe the low 50s. Certainly not the 70s. Notwithstanding all the sub-one-day specks that are being promoted beyond their proper station.
A better measure of solar activity is the F10.7 radio flux, predicted to peak at around 120. The SSN may be useless due to the Livingston and Penn effect, so any statement like yours may be quite meaningless: http://www.leif.org/research/Predicting%20the%20Solar%20Cycle%20(SORCE%202010).pdf
SandyInDerby says:
August 10, 2011 at 10:42 am
So this wasn’t quite correct?
It is all a question of size. If you include smaller and smaller effects no statement is correct. The issue is to what degree there are any practical, observable differences.
Leif Svalgaard says: “All parts of the sun are ‘tugged’ the same way by the distant planets [the ‘center of mass’ has no mass and does not ‘tug’], so move together [except for the very tiny millimeter-sized tides caused by the planets].”
Is this based on the assumption that the sun has constant density throughout?
If one is traveling at a constant velocity, one does not ‘feel’ the velocity. If there is a change in velocity, one ‘feels’ the change.
If an astronaut is accelerating in a constant gravitational field without restriction, the acceleration will be constant and the astronaut will be in ‘free fall’ and will not feel the acceleration. If the gravitational field were to be non constant, the acceleration would be non constant and the astronaut would feel the change in acceleration.
The barycenter of the solar system is a convenient mathamatical calculation. It is a point without dimension or mass. If you were an astronaut midway between the barycenter and the sun, you would not accelerate towards the barycenter, you would accelerate towards the sun.
The fact that the barycenter moves and the fact that the sun’s position in the Solar system is not constant is a function of the changing gravitational field associated with the changing position of the Solar system’s members. Because the gravitation field changes, the acceleration of the sun changes. The sun ‘feels’ the changing acceleration. The sun is not in free fall about the barycenter.
Ninderthana says:
August 10, 2011 at 9:50 am
Leif is right about the Sun being in free-fall about the barycentre. The Sun’s relatively large size with respect to the distance from the Barycentre does not change the fact that all of the particles within the Sun are free-falling towards the Barycentre and therefore feel no external force.
…image[ine] that you are looking at the Sun from Jupiter, which is slowly moving around the Sun once every 11.86 years. What you see is a torus (or ring) of plasma in the convective layer of the Sun that is slowly rotating compared to the polar regions of the Sun.
Hi Nindathana. It’s true that the Galilean transformation for the frame of the barycentre orbiting sun provides a weak, but non-zero, force. Regarding your other ideas, maybe we are starting to think along similar lines again:
http://tallbloke.wordpress.com/2011/08/10/brainteaser-relationship-between-mass-and-orbital-distance/
About now would be a great time to make your finding on the J-S synodic cycle relationship to the Sun clear I think.
jorgekafkazar says:
August 10, 2011 at 11:04 am
Is this based on the assumption that the sun has constant density throughout?
Of course not. Each little piece of the sun acts the same way no matter its density. In A hammer and a feather fall at the same rate: http://nssdc.gsfc.nasa.gov/planetary/lunar/apollo_15_feather_drop.html
David Reese says:
August 10, 2011 at 11:14 am
If an astronaut is accelerating in a constant gravitational field without restriction, the acceleration will be constant and the astronaut will be in ‘free fall’ and will not feel the acceleration.
An astronaut in orbit about the Earth feels nothing although his acceleration changes all the time [its direction]
The sun is not in free fall about the barycenter.
All separate bodies in the solar system are in free fall, including the sun, all the time
tallbloke says:
August 10, 2011 at 11:22 am
Hi Nindathana. It’s true that the Galilean transformation for the frame of the barycentre orbiting sun provides a weak
The proper transformation is that of General Relativity.
There are no gravitational forces, no free fall, no tidal forces, only masses moving in straight lines through space curved by the existence of those and other masses.
Leif Svalgaard says:
August 10, 2011 at 10:55 am
Best I could find on sunpot size is 3 millionths of the area of the visible Solar disk as a lower limit.
Doing a relative brightness profile across a 3 x 10E6 spot/pore reveals a very shallow depression.
Part of the L&P effect gives rise to larger areas with no distinct umbra structure.
Examination of sunpot groups over time leads to a pulsing behavior, going from distinct groups to shallow and short-lived.
Leif Svalgaard says:
August 10, 2011 at 10:46 am
Just countering misinformation as one should.
Nothing wrong with calling it as we see it I agree. Plenty of observational evidence is stacking up for planetary effects on the Sun. The correct mechanisms (probably plural IMO) will eventually be sorted out.
But we on the Earth do not feel that force. Just like an astronaut in free fall around the Earth is accelerated all the time [his direction is changing], yet is weightless and feels nothing.
Leif I love ya but this is a bad statement. The acceleration of gravity is exactly balanced by the velocity of the object, thus there is zero acceleration. By definition acceleration means a change in velocity and there is no change in velocity in orbit only the vector of direction.
I know that you know this, it is just the imprecise use of language here.
Leif Svalgaard says:
August 10, 2011 at 11:31 am
An astronaut in orbit about the Earth feels nothing although his acceleration changes all the time [its direction].
The astronaut feels nothing because the constant [magnitude] grravitational field is always aligned with the astronauts free fall direction. The same can’t be said about the sun.
Leif Svalgaard says:
August 10, 2011 at 11:31 am
All separate bodies in the solar system are in free fall, including the sun, all the time.
As such one could say they can’t feel aything. Tell that to Shoemaker-Levy 9, which broke apart under the influence of Jupiter’s gravitational field.
Leif Svalgaard says:
August 10, 2011 at 10:55 am
A better measure of solar activity is the F10.7 radio flux,
When is the next TSI measuring device going up Leif?
Leif Svalgaard says:
August 10, 2011 at 10:55 am
It is all a question of size. If you include smaller and smaller effects no statement is correct. The issue is to what degree there are any practical, observable differences.
It’s a brave man that says because something is barely measurable in one frame of reference it’s not measurable in all.
Leif,
Thanks for the reference. I still have a “nebulous question in my mind”. However, you’ve given me the basic info I requested, and now its up to me to make effective use of it.
Kasuha says:
August 10, 2011 at 9:08 am
If you wish to believe there is causation, feel free to believe in that. But please don’t take it for granted because no real scientist will grant you it really works until either the correlation is much better or the causation mechanism is known.
The reason why so many people speculate on a mechanism is the correlations ARE good.
http://tinyurl.com/2dg9u22/images/solanki_sharp_detail1.jpg
The LSC continues to show SC24 tracking with SC5. At the time of writing the Sun is blank.
http://tinyurl.com/2dg9u22/images/sc5_sc24.png
Dennis Wingo says:
August 10, 2011 at 12:25 pm
By definition acceleration means a change in velocity and there is no change in velocity in orbit only the vector of direction.
velocity is a vector and changing the direction is acceleration. There is no change in speed. Newton taught us acceleration = force / mass. To change direction requires a force, thus a change of direction is acceleration. But you are correct that one has to be careful with the exact wording. Physicists often use and mix language loosely from different paradigms because they all know them and no confusion arises.
David Reese says:
August 10, 2011 at 12:31 pm
The astronaut feels nothing because the constant [magnitude] gravitational field is always aligned with the astronauts free fall direction. The same can’t be said about the sun.
The sun falls under the influence of the gravitational ‘field’ and thus freely. Nothing else there to make it change direction or speed. Definition: ‘free fall’ is movement when the only forces present are gravitational.
As such one could say they can’t feel aything. Tell that to Shoemaker-Levy 9, which broke apart under the influence of Jupiter’s gravitational field.
Tidal forces can be very strong near a massive body. The tidal forces on the Sun are extremely small, thus making its movement VERY close to a free fall.
tallbloke says:
August 10, 2011 at 1:07 pm
When is the next TSI measuring device going up Leif?
The replacement for SORCE fell into the Pacific ocean upon launch, but the PICARD mission now in orbit also measures TSI: http://arxiv.org/abs/1106.2198
SandyInDerby says:
August 10, 2011 at 2:27 pm
It’s a brave man that says because something is barely measurable in one frame of reference it’s not measurable in all.
Not really anything to do with reference frames. My speed in the reference frame of a flying aircraft is zero, but may be 1000 km/s in the frame of the ground. What is important is if that ‘something’ has any observable or practical significance. It is absurd to tell my doctor that I lost 0.00000000000000001 pounds since I visited him last.