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PraedSt
2009-Jun-27, 06:37 PM
Warning! Possible ATM! :lol:

I found this paper on arXiv (http://arxiv.org/abs/0906.4371).

Basic proposal is this:

Orbital resonances of outer planets ---> destabilizes orbits of KBOs ---> KBOs impact Sun ---> sunspots!

According to the authors, the characteristics of the Solar cycle are well explained by this model. The paper itself is actually quite easy to follow, and having read it I only have two gripes. One is that the correlations seem to be on the low side to me. (Having said that, I have no idea what "good" and "poor" correlations are in astronomy). The other is the standard one- correlation does not imply causation. What we need to see is an impact!

Ok, I thought this was pure ATM, but having had a quick look round I see that the underlying cause of the Solar cycle is still in dispute. It was only a quick look mind you, so if anyone knows of the mainstream cause, I would love to hear it.

This is the abstract:
Five new correlations between sunspot activity and orbiting position of the Jovian planets are detected. In order to explain these correlations it is suggested that the resonance of the outer planets destabilizes the orbit of Kuiper Belt Objects and generates a cyclical impact frequency on the Sun. The vaporization of the object initiates a shock wave disrupting the upwelling of the plasma resulting in a sunspot formation. The proposed model is able to explain the length of the cycle, the latitude distribution of the sunspots and the extremely long term stability of the cycles. Calculating the positions of the Jovian planets at conjunction and opposition allows the long term prediction of the solar activity.

novaderrik
2009-Jun-27, 06:45 PM
i think we've actually got footage of comets slamming into the sun without causing any sort of a reaction beyond the "pffft" when it hits.

orionjim
2009-Jun-28, 01:01 PM
His correlation of planet cycles to sunspots seems correct except the picture I have in my mind is he’s off by 180 degrees. If you were to plot sunspots max and min relative to Jupiter I think you’ll find that the minimum sunspots are when it’s closest to the Sun and the Maunder Minimum happened when Jupiter, Saturn and Neptune were closest to the Sun. His theory suggests that it would be a solar maximum.

Also, if you study sunspots you would see his theory ignores Hales Law, Joy’s Law and the equatorward drift of sunspots and the 11 year reversal of the solar polar magnetic fields. See:
http://solarscience.msfc.nasa.gov/dynamo.shtml

Sunspots are weird. If you look at the NASA site you will see the Sun does a double reversal; it’s not a simple flip of the North-South poles, but it also does an East-West flip. It’s like the Sun is turning inside out.

Also from the Ulysses Mission they have been able to get a fairly good picture of the solar magnetic conveyor and that makes it tough to argue that sunspots happen from an external source.

Also as novaderrik said; we've seen comets being pulled into the Sun and haven't tied them to sunspots.

I will say that I looked up the author, Jozsef Garai and he has 8 to 10 peer reviewed papers and is involved in many different things. But I think this theory just doesn't add up.

Jim

PraedSt
2009-Jun-28, 04:16 PM
Closest? As in perihelion? The author uses longitude, not distance, but I might have missed something there.

As far as I know, the magnetic mechanism describes sunspots and their formation, but they can't account for the periodicity. Maybe the mechanism has inherent cyclicality? I don't know.

Perhaps a barrage of KBOs trigger a self-sustaining magnetic process? We know magnetism explains a great deal. If this author is also on the right track, it suggests an interaction between the two processes.

I've found another gripe with the paper. If KBOs are indeed disturbed from their orbits, they would take a significant amount of time to hit the Sun. There would be a lag between the two cycles, and this may be the reason for the low correlations. He doesn't even mention a lag in his discussion.

orionjim
2009-Jun-28, 06:04 PM
Closest? As in perihelion? The author uses longitude, not distance, but I might have missed something there.
...


Yes perihelion. I pictured his use of longitude as trying to explain the butterfly pattern, but then I may have misunderstood what he was getting at.

I pictured what he was saying was when planets like Jupiter and Saturn orbiting around the sun would pass by the Kuiper Belt picking stuff up and when they were going towards the Sun its gravity would pull them towards it. This happens when the planets are going towards the perihelion. I did some calculations once and Jupiter, Saturn and Neptune were closest to the Sun near the time of the Maunder Minimum. If his theory was correct, I would think when you have three massive planets heading towards the Sun, you are going to get a lot of sunspots.


Perhaps a barrage of KBOs trigger a self-sustaining magnetic process? We know magnetism explains a great deal. If this author is also on the right track, it suggests an interaction between the two processes.

Now that is an interesting thought. They could interact with the Current Sheet somehow and then maybe… See:
http://science.nasa.gov/headlines/y2003/22apr_currentsheet.htm

Jim

PraedSt
2009-Jun-28, 06:51 PM
I just had a thought. From the article:
The influence of the solar cycle was so much stronger 680 Myr ago than today (Williams,1981).The weakening of the cycle can be explained by the depletion of the KBO.Maybe that's why our Sun's so quite these days. The Kuiper Belt's empty! :lol:

PraedSt
2009-Jun-28, 07:02 PM
Yes perihelion. I pictured his use of longitude as trying to explain the butterfly pattern, but then I may have misunderstood what he was getting at.

I pictured what he was saying was when planets like Jupiter and Saturn orbiting around the sun would pass by the Kuiper Belt picking stuff up and when they were going towards the Sun its gravity would pull them towards it. This happens when the planets are going towards the perihelion. I did some calculations once and Jupiter, Saturn and Neptune were closest to the Sun near the time of the Maunder Minimum. If his theory was correct, I would think when you have three massive planets heading towards the Sun, you are going to get a lot of sunspots.



Now that is an interesting thought. They could interact with the Current Sheet somehow and then maybe… See:
http://science.nasa.gov/headlines/y2003/22apr_currentsheet.htm

JimHe says he can't explain the Maunder Minimum yet.
Thus the determined correlations are not applicable to the period of the Maunder minimum indicating that additional term/s might be required for longer and more precise description of the solar activity.
And about the butterfly pattern:
It is also suggested that the objects hitting the Sun originate from the Kuiper Belt. The inclination of the Kuiper Belt Objects is between 0-35o (Luu and Jewitt, 2002; Jewitt et al., 2008) which is consistent with the observed latitude distribution of the sunspots.
...
The observed butterfly distribution of the sunspots can be shown consistent with the proposed impact model. The impact free zone around the solar equator at the beginning of the cycle is the result of the shielding effect of Jupiter and Saturn.

The bit about the Current Sheet you mention is interesting. Maybe you don't need impacts; maybe planetary alignment of some sort is sufficient? Pure speculation...

Nick Theodorakis
2009-Jun-28, 07:18 PM
OK, here's a stupid question: If there were enough KBOs hitting the sun to produce the number of sunspots we see, shouldn't there be a lot more comets visible in the inner solar system when there are sunspots?

Nick

R.A.F.
2009-Jun-28, 07:21 PM
That sounds suspiciously like evidence of causation. ATM ideas (and this sure looks like one to me) don't require that.

PraedSt
2009-Jun-28, 07:36 PM
OK, here's a stupid question: If there were enough KBOs hitting the sun to produce the number of sunspots we see, shouldn't there be a lot more comets visible in the inner solar system when there are sunspots?

NickNo, good question. That's exactly what should be measured. Unfortunately I don't think it's been done. I also think it's also not so easy to do accurately. Short period comets can be hard to spot- it was only when SOHO started blotting out the Solar disc that we started spotting many more comets.

PraedSt
2009-Jun-28, 07:39 PM
That sounds suspiciously like evidence of causation. ATM ideas (and this sure looks like one to me) don't require that.
This looks like ATM to me as well. The problem is I don't know the mainstream answer to what causes the Solar cycle. Wiki and other sites that I've checked say it's disputed. I think I'll PM tusenfem, he seems to know about this sort of stuff. :)

tdvance
2009-Jun-28, 08:05 PM
Well, the sunspot cycle is 11 years, and Jupiter's is around 12 years, so over any 50 year period, there would certainly be correlation.

tusenfem
2009-Jun-30, 10:20 AM
TRARAAAAATRARAAAAAAAAAAAAAAAAAAAA!!!!!!!!!!! TRUMPET BLAST!!!!!!!!!!!!!!!!!

In comes tusenfem, superhero grandiose, flying on his wicker picknick basket.

There is no clear theory on why and how the solar cycle works. Numerical models of dynamo action in the (convection layer of) the sun, do show however, that the magnetic field is always changing and that reversals (also in the Earth's dynamo) are part of that, it all being a dynamic process. (well there is a real nothing saying explanation).

At ADS I found the following list of published papers (http://esoads.eso.org/cgi-bin/nph-abs_connect?db_key=AST&db_key=PHY&db_key=PRE&qform=PHY&arxiv_sel=astro-ph&arxiv_sel=cond-mat&arxiv_sel=cs&arxiv_sel=gr-qc&arxiv_sel=hep-ex&arxiv_sel=hep-lat&arxiv_sel=hep-ph&arxiv_sel=hep-th&arxiv_sel=math&arxiv_sel=math-ph&arxiv_sel=nlin&arxiv_sel=nucl-ex&arxiv_sel=nucl-th&arxiv_sel=physics&arxiv_sel=quant-ph&arxiv_sel=q-bio&aut_logic=OR&author=&ned_query=YES&sim_query=YES&start_mon=&start_year=&end_mon=&end_year=&ttl_logic=AND&title=solar+dynamo+solar+cycle&txt_logic=OR&text=&nr_to_return=200&start_nr=1&jou_pick=NO&ref_stems=&data_and=ALL&group_and=ALL&start_entry_day=&start_entry_mon=&start_entry_year=&end_entry_day=&end_entry_mon=&end_entry_year=&min_score=&sort=SCORE&data_type=SHORT&aut_syn=YES&ttl_syn=YES&txt_syn=YES&aut_wt=1.0&ttl_wt=0.3&txt_wt=3.0&aut_wgt=YES&obj_wgt=YES&ttl_wgt=YES&txt_wgt=YES&ttl_sco=YES&txt_sco=YES&version=1) in peer reviewed journals.

Unfortunately, I am not well versed in the details of dynamo theory on this scale. I understand the idea of generating the field, but I have no real insight in the instabilities that happen in this dynamic process and which cause the orientation to flip.

Indeed, it is often remarked on that there is a correlation between Jupiter's orbital period and the solar cycle. However, correlation is no causation. These things have been discussed here on the board (I should do a search (http://www.bautforum.com/against-mainstream/71027-jupiter-influencing-sunspots.html), done and found this thread from last year) and some of the ideas of driving the sunspots were discussed.

I am not sure what exactly you want to do with the current sheet. This is created because of the (on large scale) dipolar magnetic field of the Sun, and separates the regions of oppositely directed magnetic field. This sheet is necessary because of Maxwell's equations (wow! that is a stupid comment!) But basically, the planets (even Jupiter) are so small that they have little or no influence on the current sheet. I do not see, e.g. large Alfvén waves shooting from the planet to the Sun, also because the current sheet in naturally embedded in the solar wind.

Well that was no help at all, as a quick response. I am a bit busy, maybe a bit later I can give more information. BTW Papageno seems to know about experiments with dynamos.

ByeByeeeeeeeeeeeeeeeeeeeeeeeeee

PraedSt
2009-Jun-30, 03:35 PM
Well that was no help at all, as a quick response. I am a bit busy, maybe a bit later I can give more information. BTW Papageno seems to know about experiments with dynamos.
No that was helpful, I'll go through those links later. Thanks.

PraedSt
2009-Jun-30, 03:45 PM
Coming back to Garai's KBO impact theory, there is the OP paper, and another that he presented at a 2001 AGU conference. (That's American Geophysical Union).

Part of the abstract:
The gravitational attraction of the solar system captures interstellar comets. The flux of these incoming comets fluctuates as a result of fluctuating gravitational fields within solar system, dominated by the HCOJS. These comets impact the sun with a time delay and cause the known solar cycle. This cometary impact model for the origin of sunspots is further supported by the following observations:
1) A continuum model cannot explain the observed temperature differences in the sunspot umbra.
2) Highly congested water spectral lines in the sunspots have been detected.
3) Most of the missing radiated energy at the site of the sunspots has never been detected, indicating an external cooling process.
4) The inverse correlation between the sunspot density and the rotational period at the corresponding latitude of the sun is consistent with an impact model.
5) The observed butterfly distribution of the sunspots can be shown to be consistent with the proposed impact model.

Ok, he points to evidence supporting impacts. Fine. But I want to see how he thinks an impact can produce a sunspot. How would an impact affect the magnetic field? What's the mechanism? Questions, questions..

Mike Holland
2009-Jul-03, 11:30 PM
THios is just too far-fetched. The sunspot cycle is a symptom of an 11-year solar cycle that shows up in tree rings and varves going back many thousands of years. Are we to suppose that a periodic disturbance of some random objects floating in the KB would produce a hit on the sun (an extremely small target, viewed from the KB) regularly every 11 years for thousands of cycles?

Ara Pacis
2009-Jul-04, 06:39 AM
We saw how large of an impact comet fragments had on Jupiter.

Would the sun react similarly or with an even bigger splotch? I don't know the densities of the jovian atmosphere and the sun or how deep the impact might have reached on either. Would an impactor always hit straight on, pulled into a perpendicular death dive or would you often or sometimes get an oblique impact angle? What are the speeds of such an impact and the energies? How deep would an impactor survive as it dove into the sun? Does it have to hit in a certain spot with regards to magnetic fields to trigger a sunspot or would any impact potentially cause one?

Lotsa questions.

AstroRockHunter
2009-Jul-04, 04:40 PM
We saw how large of an impact comet fragments had on Jupiter.

Would the sun react similarly or with an even bigger splotch? I don't know the densities of the jovian atmosphere and the sun or how deep the impact might have reached on either. Would an impactor always hit straight on, pulled into a perpendicular death dive or would you often or sometimes get an oblique impact angle? What are the speeds of such an impact and the energies? How deep would an impactor survive as it dove into the sun? Does it have to hit in a certain spot with regards to magnetic fields to trigger a sunspot or would any impact potentially cause one?

Lotsa questions.

One thing that we have to remember is that the Sun is a whole lot hotter than Jupiter. With the corona temp. at about 1 million C, I'm thinking that much of the impactor would be vaporized before it reached the photosphere. If that is the case, then the original size of the impactor would have to be HUGE for the remnant to be large enough to cause a sunspot large enough to hold 300 earth size objects. Add to that the fact that multiple unrelated sunspots appear regularly would imply that there should be some documented visual evidence to support the theory.

Ara Pacis
2009-Jul-04, 08:48 PM
One thing that we have to remember is that the Sun is a whole lot hotter than Jupiter. With the corona temp. at about 1 million C, I'm thinking that much of the impactor would be vaporized before it reached the photosphere. If that is the case, then the original size of the impactor would have to be HUGE for the remnant to be large enough to cause a sunspot large enough to hold 300 earth size objects. Add to that the fact that multiple unrelated sunspots appear regularly would imply that there should be some documented visual evidence to support the theory.

Thinking is a start, data and calculation is better. Yes, I know it's hotter, however, I'm not capable of determining and calculating effect it would have on an impactor, hence the questions.

So, here are some more specific questions, in case someone knows the answers. What would be the transit time of an object through the outer atmosphere of the sun? Would heat influx be mostly from radiating energy or from conduction via interactions with the low density atmosphere at those altitudes? Would the offgassing shroud the impactor reducing radiation heating? How much momentum would the impactor still have even if it was all or partially ablated into gas? How large would the shock waves be and how far would they propogate through such levels of the solar atmosphere and/or deeper? Would an impact into the sun reach temperatures high enough to cause fusion reactions in the impactor debris?

AstroRockHunter
2009-Jul-04, 10:57 PM
Thinking is a start, data and calculation is better. Yes, I know it's hotter, however, I'm not capable of determining and calculating effect it would have on an impactor, hence the questions.

So, here are some more specific questions, in case someone knows the answers. What would be the transit time of an object through the outer atmosphere of the sun? Would heat influx be mostly from radiating energy or from conduction via interactions with the low density atmosphere at those altitudes? Would the offgassing shroud the impactor reducing radiation heating? How much momentum would the impactor still have even if it was all or partially ablated into gas? How large would the shock waves be and how far would they propogate through such levels of the solar atmosphere and/or deeper? Would an impact into the sun reach temperatures high enough to cause fusion reactions in the impactor debris?

One thing that we do know is that the typical depth of a sunspot is only about 3km.

Merkin Muffley
2009-Jul-04, 11:30 PM
Looks like data mining to me.


(Having said that, I have no idea what "good" and "poor" correlations are in astronomy).

I think that's the right question to ask. A useful exercise would be to go looking for correlations with a completely fictitious frequency of sunspot cycle, and see how many can be found. Kind of like giving random data to technical traders and asking them to analyze it.


The other is the standard one- correlation does not imply causation. What we need to see is an impact!

Normally, I would agree, but since we know the mechanism that causes the planets to move in their orbits (gravity), neither reverse causality nor joint causality by some third phenomenon seems likely.

I think it is almost certainly a case of going out to look for things that, in sample, are correlated with a given cycle, and finding them, without even pretending to do any statistical analysis of the results. If these are regular, reasonably non-random phenomena, then they have to occur with a given frequency, and the frequencies with which some things happen, are going to be close to the frequencies with which other things happen.

tusenfem
2009-Jul-05, 11:02 AM
Well, finally reading the paper, I guess there are some comments to make on the ideas by Garai.

In the introduction



The convection of the hot plasma which rises up from the interior sun and spreads out across the surface and then cools and sinks inward is without any doubt random. Random process can not generate a nonrandom process. Thus the sunspot formation should not originate from and relate to random plasma convection.


Well, the assumption that from "random" processes no structure can be created is incorrect. For one, why would the convection be "random" (what does Garai mean with random here?) whilst it is rather structured. One other phenomenon related to this "randomness" would be the hexagonal structure at the poles of Saturn and other structures. So, that is not an argument, it basically shows that Garai is not up to date with what plasmas do.

The next paragraph about "there is no known other process [than planetary motion] able to sustain this long-term stability" is just plain silly, the sun has been convective for billions of years, and will remain so for more billions, again a pointer that Garai does not know about plasma physics and solar physics.

Then



It is assumed that if an HCOJS is skipped then irregularities in the following three cycles could occur. Based on this assumption solar cycles following the HCOJS of 1703; 1713; 1802; 1812; 1822; 1881; 1892; 1902 can be identified as irregular. I will call the rest of the cycles regular.


This is all very nice, but it does not mean a thing, the usual premise: "correlation is not causation" is swept off the table under the rug, without any valid model of why the HCOJS is creating the sunspot latitudinal behaviour.

Then one correlation:



small heliocentric longitudes of Jupiter at the time of HCOJS correlate to low solar
maximums and high latitudes to high activity


No, I am a bit at a loss, because the heliocentric longitude of Jupiter is not defined in the paper. What is zero? Is it when Jupiter is at perihelion or what? (I guess I have to look up Smith 1981 to get to know that.)

But the best thing comes after this, the correlations:



The correlations are:
MSN = 97.88 + 0.1255 x JHL (R) R = 0.42 (1)
where MSN is the Maximum Yearly Average Sunspot Number, JHL is the Heliocentric
Longitude of Jupiter at the time of HCOJS and R is the correlation coefficient. Subscript R refers to regular cycles.
MSN = 143.05 - 0.2196 x JU (R) R = 0.41 (2)
where, JU is the angle between Jupiter and Uranus at the time of HCOJS.
MSN = 106.94 + 0.1835 x JN (R) R = 0.33 (3)


I don't know if I should laugh or cry here. If I take an absolute random data set and correlate it somehow, I am quickly apt to get a correlation coefficient of 0.5 (I have a nice paper somewhere describing this, but drawing conlcusions (in what weak form they might be) from data sets with correlations less than 0.5 is laughable. This is best illustrated by looking at Figure 2 of the paper. Does anyone believe these fits? Would you not rather draw a horizontal line through those scatter plots? I am curious how Garai fitted those points, and whether he used the correct linear regression technique for these data points.

There was a question by PreadSt "I have no idea what "good" and "poor" correlations are in astronomy". I hope I answered that a bit. One of the ways of checking whether there IS a pattern here is the method by Mike Brown, just randomly reassign the y-data over the x-data and do the regression once more (and do that a LARGE number of times). If there really is a pattern, then it will come out, as all random permutations will not give as high a correlation coefficient.

Now, the question is wheter Garai's equations (4) and (5) are valid or not. Apparently, he thinks that when I find three relations, I can somehow just add them together. I have no idea how he comes from (1,2,3) to (4), did he do a multi variant fit to the data or what? How come, angular dependence numbers suddenly change? And how did he get the high correlation coefficient? This smells very fishy.



The presented correlations between solar activity and the position of the Jovian planets eliminate the likelihood that these correlations are random coincidences. No known internal solar mechanism can explain how Uranus and Neptune could have any direct effect on the Sun. However the observed correlations can be explained by impact generated sunspot formation (Garai, 2001).


This is preposterous, Garai never showed a real correlation. Correlations only start to means something when 0.8 or preferably higher! The fact that Garai (2001) is a reference to an abstract of the AGU spring meeting instead of a real paper, says enough.

Then, for no reason at all, the KBO's are put into play. How about showing some stuff that the orbits of KBO's are disturbed enough here? Maybe some observations (there ARE observations of comet hitting the Sun) or something. But nothing.



An impact model is consistent with the cooler temperature of the sunspots and explains why most of the missing radiated energy at the site of the sunspots has never been detected (Rast et al., 1999).


Ehhhh "most of the missing radiation never been detected?" What exactly is that supposed to mean? Dunno, Rast et al. 1999 does not appear in the bibliography. So, I guess he thinks, well sunspots are colder that the rest of the suface of the Sun, so I just throw in a big ice block, then the plasma cools and tadaaaaah a sunspot. Now, how big are these suposed KBO's that plunge in the Sun that can create a "hole" that is several time the size of the Earth? Why does the sunspot not heat up quickly after the ice has been evaporated? Why does it turn into a magnetic object? Why ... why ... why ...

To conclude:



The presented correlation is the first one which is able to give reasonable prediction for longer term solar activity.


I am dumbfounded. And also, going back to the title:



IMPACT GENERATED SHOCKWAVES ARE PROPOSED FOR THE ORIGIN OF SUNSPOTS TO EXPLAIN THE DETECTED PLANETARY EFFECTS ON THE SOLAR ACTIVITY


mmmm I guess one should just shorten the title to the part in green, and then I am being generous. This whole paper is bunk, this was a waste of one sunny sunday morning hour.

Ara Pacis
2009-Jul-05, 06:55 PM
Ehhhh "most of the missing radiation never been detected?" What exactly is that supposed to mean? Dunno, Rast et al. 1999 does not appear in the bibliography. So, I guess he thinks, well sunspots are colder that the rest of the suface of the Sun, so I just throw in a big ice block, then the plasma cools and tadaaaaah a sunspot. Now, how big are these suposed KBO's that plunge in the Sun that can create a "hole" that is several time the size of the Earth? Why does the sunspot not heat up quickly after the ice has been evaporated? Why does it turn into a magnetic object? Why ... why ... why ...

This is what I want to know too. If there is some sort of feasible process for an impact causing a sunspot, that would be the key to the hypothesis and the orbital data would merely affect the timing. As for the "cooling" I assumed it was referring to some sort of shockwave effect adjusting convection cells, not a heat absorption via cold impact debris, but who knows what he meant.

Jerry
2009-Jul-05, 10:51 PM
There is at least one more obvious problem:

In order for 'destablized' KBO's to hit the sun with any systemic frequency, they would have to be lined up like soldiers, winding into the sun at more-or-less the same initial path. Nothing in our observational experience remotely suggests that the orbits of KBOs (which turned out to be far fewer than expected) are resonant.

tusenfem
2009-Jul-06, 05:34 AM
There is at least one more obvious problem:

In order for 'destablized' KBO's to hit the sun with any systemic frequency, they would have to be lined up like soldiers, winding into the sun at more-or-less the same initial path. Nothing in our observational experience remotely suggests that the orbits of KBOs (which turned out to be far fewer than expected) are resonant.

Yeah, true, I decided to not even go into this whole issue, basically, because it is not really addressed at all in the paper. The title absolutely does not describe the content.

tusenfem
2009-Jul-06, 05:35 AM
This is what I want to know too. If there is some sort of feasible process for an impact causing a sunspot, that would be the key to the hypothesis and the orbital data would merely affect the timing. As for the "cooling" I assumed it was referring to some sort of shockwave effect adjusting convection cells, not a heat absorption via cold impact debris, but who knows what he meant.

Well, as basically only the correlations have been discussed (and even badly at that) and no mention at all is given about what the creation process is in the paper, we can all but guess.