From NASA News: Are Sunspots Disappearing?
September 3, 2009: The sun is in the pits of the deepest solar minimum in nearly a century. Weeks and sometimes whole months go by without even a single tiny sunspot. The quiet has dragged out for more than two years, prompting some observers to wonder, are sunspots disappearing?
“Personally, I’m betting that sunspots are coming back,” says researcher Matt Penn of the National Solar Observatory (NSO) in Tucson, Arizona. But, he allows, “there is some evidence that they won’t.”
Penn’s colleague Bill Livingston of the NSO has been measuring the magnetic fields of sunspots for the past 17 years, and he has found a remarkable trend. Sunspot magnetism is on the decline:
Above: Sunspot magnetic fields measured by Livingston and Penn from 1992 – Feb. 2009 using an infrared Zeeman splitting technique. [more]
“Sunspot magnetic fields are dropping by about 50 gauss per year,” says Penn. “If we extrapolate this trend into the future, sunspots could completely vanish around the year 2015.”
This disappearing act is possible because sunspots are made of magnetism. The “firmament” of a sunspot is not matter but rather a strong magnetic field that appears dark because it blocks the upflow of heat from the sun’s interior. If Earth lost its magnetic field, the solid planet would remain intact, but if a sunspot loses its magnetism, it ceases to exist.
“According to our measurements, sunspots seem to form only if the magnetic field is stronger than about 1500 gauss,” says Livingston. “If the current trend continues, we’ll hit that threshold in the near future, and solar magnetic fields would become too weak to form sunspots.””This work has caused a sensation in the field of solar physics,” comments NASA sunspot expert David Hathaway, who is not directly involved in the research. “It’s controversial stuff.”
The controversy is not about the data. “We know Livingston and Penn are excellent observers,” says Hathaway. “The trend that they have discovered appears to be real.” The part colleagues have trouble believing is the extrapolation. Hathaway notes that most of their data were taken after the maximum of Solar Cycle 23 (2000-2002) when sunspot activity naturally began to decline. “The drop in magnetic fields could be a normal aspect of the solar cycle and not a sign that sunspots are permanently vanishing.”
Penn himself wonders about these points. “Our technique is relatively new and the data stretches back in time only 17 years. We could be observing a temporary downturn that will reverse itself.”
The technique they’re using was pioneered by Livingston at the NASA-supported McMath-Pierce solar telescope near Tucson. He looks at a spectral line emitted by iron atoms in the sun’s atmosphere. Sunspot magnetic fields cause the line to split in two—an effect called “Zeeman splitting” after Dutch physicist Pieter Zeeman who discovered the phenomenon in the 19th century. The size of the split reveals the intensity of the magnetism.
Right: Zeeman splitting of spectral lines from a strongly-magnetized sunspot. [more]
Astronomers have been measuring sunspot magnetic fields in this general way for nearly a century, but Livingston added a twist. While most researchers measure the splitting of spectral lines in the visible part of the sun’s spectrum, Livingston decided to try an infra-red spectral line. Infrared lines are much more sensitive to the Zeeman effect and provide more accurate answers. Also, he dedicated himself to measuring a large number of sunspots—more than 900 between 1998 and 2005 alone. The combination of accuracy and numbers revealed the downturn.
If sunspots do go away, it wouldn’t be the first time. In the 17th century, the sun plunged into a 70-year period of spotlessness known as the Maunder Minimum that still baffles scientists. The sunspot drought began in 1645 and lasted until 1715; during that time, some of the best astronomers in history (e.g., Cassini) monitored the sun and failed to count more than a few dozen sunspots per year, compared to the usual thousands.
“Whether [the current downturn] is an omen of long-term sunspot decline, analogous to the Maunder Minimum, remains to be seen,” Livingston and Penn caution in a recent issue of EOS. “Other indications of solar activity suggest that sunspots must return in earnest within the next year.”
Whatever happens, notes Hathaway, “the sun is behaving in an interesting way and I believe we’re about to learn something new.”
h/t to Michael Ronayne
Sandy (16:28:23) :
“Leif Svalgaard (22:47:01):
Leif is right. A plasma has balanced charges, at least until magnetic fields or whatever get it moving. So a plasma, in its rest frame, ie. when it’s stationary, has no net electric or magnetic field.
Quantum tunnelling is an effect where a particle has a finite chance of tunnelling through a potential barrier that is of the order of the Schrödinger wavelength of the particle. Since the Sun is hot all particles have high thermal energy hence v. v. short wavelengths below the size of the atom and nearly the size of the nucleus.
The idea of QT in the Sun seems far-fetched.
Read the next texts:
Frank H. Shu. The physical universe: an introduction to astronomy. 1982. University Science Books. Sausalito, CA. Page 99.
Maoz, Dan. Astrophysics. 2007. Princeton University Press. Princeton, New Jersey. Pp. 50 – 51
http://books.google.com/books?id=v_6PbAfapSAC&dq=frank+h.+shu+the+physical+universe&printsec=frontcover&source=bl&ots=oopjnWeeeJ&sig=HnG9zK2A4H6Ovr8b14LHM5FBQPM&hl=en&ei=v2ugSpXkNZH2sQP9w8GNDw&sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=&f=false
There are 10^57 protons in the Sun. The fraction of nuclei with energies above 1 MeV to start a nuclear reaction, from the classical view, is ~1.6 x 10^-434; so there is not a single proton in the Sun which could enter into nuclear fusion reaction without the influence of an external operator. It could be electricity or quantum tunneling. To work like an external operator, the electricity must to have been produced by a body located externally with respect to the solar system; consequently, the only feasible option is quantum tunneling.
Sandy (16:28:23) :
” So a plasma, in its rest frame, ie. when it’s stationary, has no net electric or magnetic field.”
Yes, but plasma is rarely at rest, it is constantly on the move.
“Couple questions –
Is a moving plasma by itself an electric current?”
~~ No, there must be a net flow of charge, having said that the -ve electrons are so much lighter than the +ve nuclei that almost any movement leads to charge separation and hence current.
“In an ion drive exhaust, we have ionized xenon. Does that positively charged stream have an electric field in its rest frame?”
~~ Yes it does have a field because in its rest frame it is stationary +ve charge.
Nasif: Your calculations are presumably based on some assumptions about the pressure and temperature in the centre of the Sun and you conclude fusion is unlikely. However we know that fusion occurs, so it may just be the assumptions that are unlikely.
“consequently, the only feasible option is quantum tunneling.”
is the same logic as Man’s CO2 causes Global Warming, and presumes that we know all the relevant science in order to be able to discount other effects.
If we’re playing silly physics here, remember degeneracy pressure from Pauli’s exclusion principle. Since all the fermion energy are taken to such high energy levels there might be bosonic pairing going on?
Leif Svalgaard (11:25:59) :
I have often wondered about Norway and Iceland where aurorae now are common, that if they disappeared during the MM, people would have noticed that and commented upon it as strange. The lack of any such comment may be taken as evidence, perhaps, that the aurorae did not disappear. The only real evidence we have of the solar magnetic field still being near ‘normal’ is that the modulation of cosmic rays was not noticeably weaker during the MM.
Leif isn’t the visibility of the Aurora Borealis at a given location related to the position relative to the magnetic NP? During the MM the Mag NP was closer to Norway and Iceland so that could counter a reduction by other causes.
Nasif Nahle (17:44:26)
That was a short ban.
Sandy (20:18:44) :
Nasif: Your calculations are presumably based on some assumptions about the pressure and temperature in the centre of the Sun and you conclude fusion is unlikely. However we know that fusion occurs, so it may just be the assumptions that are unlikely.
“consequently, the only feasible option is quantum tunneling.”
is the same logic as Man’s CO2 causes Global Warming, and presumes that we know all the relevant science in order to be able to discount other effects.
If we’re playing silly physics here, remember degeneracy pressure from Pauli’s exclusion principle. Since all the fermion energy are taken to such high energy levels there might be bosonic pairing going on?
Sandy… Those are not my calculations. You can read them from the references I have given.
Actually, the problem is not about thermonuclear activity, but on the Coulomb barrier, or potential barrier, which prevents that one proton fuse with another proton. The solution to this problem is quantum tunneling. Quantum tunneling can happen mainly through three simple mechanisms: transverse anisotropy, transverse magnetic field, and oscillatory density of the magnetic field in the potential barrier.
There are other more sophisticated mechanisms which allow quantum tunneling in the Sun; however, I prefer to handle the most frequent mechanisms, which are the three that I have mentioned before.
Sandy…
By the way, it is not silly physics, but quantum mechanics.
Nasif Nahle (20:54:43) :
Sandy…By the way, it is not silly physics, but quantum mechanics.
Having read Robert Gilmore’s Alice in Quantumland, I’d say they’re the same thing.
Nasif Nahle.
You really do talk some balderdash.
Quantum tunneling in the heart of a star. Really?
How and more importantly why?
Of course quantum tunnelling exists, as does the Coulomb barrier.
But at the pressures and temperatures at the heart of a star not even the Coulomb barrier can prevent fusion.
What do you imagine we are trying to do in our big Tokomaks? Make toast?
No we are trying to fuse nuclei directly despite the Coulomb barrier.
And we have shown we can, which is a long way from generating useful power from the process.
How can this happen? Simple geometry, a nucleus has a size so the Coulomb force never reaches infinity: and the nuclei touch and fuse.
That is without discussing weak and strong nuclear forces or quantum mechanics.
Simplistic but true.
I just don’t know where you get your ideas from.
Kindest Regards.
“The extremely low sunspot activity during the period of the Maunder minimum 1645-1715 was confirmed by group sunspot numbers, a new sunspot index constructed by Hoyt and Schatten (1998a,b). Neither sunspots nor auroral data time behavior indicate the presence of 11-year solar cycles as stated by Eddy (1976). The evidence for solar cycles was found in the butterfly diagram, constructed from observations made at Observatoire de Paris. After Clivier, Boriakoff, and Bounar (1998) the solar cycles were reflected also in geomagnetic activity. Results are supported by the variation of cosmogenic isotopes ^10Be and ^14C. The majority of the observed 14 naked-eye sunspots occurred on days when telescopic observations were not available. A part of them appeared in the years when no spot was allegedly observed. Two-ribbon flares appear in plages with only very small or no sunspots. Some of these flares are geoactive. Most aurorae (90%), which were observed during the Maunder minimum, appeared in years when no spot was observed. Auroral events as a consequence of proton flares indicate that regions with enhanced magnetic field can occur on the Sun when these regions do not produce any sunspots. ”
To which I will take as saying that during these extraordinary low Solar Activity levels, the Sun can produce either sunspots or proton flares giving rise to Aurora, but rarely both. I read it as a very weakened state. Low batteries.
Still, over time, it builds up and has to go somewhere.
Sure, a reconstruction can reveal the cycle, but does it tell you how strong that cycle was? Or that the Sun produced proton flares when no spots were around? Or ribbon flares with very weak spots? Apparently, there is something missing that the reconstruction cannot reveal. Relative strength is my guess.
Ric Werme (05:50:58) :
Thanks Ric- I kinda lost it there…
Of course, it’s easy to find other statistical papers that should be given a status of “latest update” instead of “the ice is going to be gone by 2030!” (or 2010) or whatever).
Agreed.
Richard M,
Thank you for responding.
I shall continue to grope my way through the fog… Not without enjoyment!
Leif Svalgaard (11:25:59) :
I have often wondered about Norway and Iceland where aurorae now are common,
A few pictures from my home at 60N, 21 Jan 2005 showing a red Aurora then
http://arnholm.org/astro/atmosphere/aurora/index.htm
I believe we may have seen more aurorae in southern norway in recent years (excluding the last couple of years) compared to e.g. the 1970s.
Kevin Kilty (14:49:28) :
Leif Svalgaard (09:25:55) :
Carsten Arnholm, Norway (07:33:14) :
“You never get up early enough to see the red Aurora over the mountain top”
So, Dass did mention the aurora after all. And sleet, too. And your translation is fine.
Is your tongue in your cheek, Leif? The aurora mentioned here looks like “the dawn” not the Aurora Borealis.
I don’t know whether you have travelled or lived in arctic regions, but if you live near the arctic circle (as Petter Dass did) during the winter and don’t get up until dawn, you are a very lazy sleeper 🙂 Few would refer to that as “early enough”.
It seems to me Petter Dass had enough knowledge of the Aurora to not confuse it with the dawn.
rbateman (17:28:57) :
Right now, how do we tell how many spots this year have fallen victim to 1800 Gauss Magnetic Arrest if we never see them?
We should see some evidence of them in the SOHO magnetograms?
rbateman (22:30:29) :
“Low batteries.”
Reply: This comment gave me an idea. Perhaps very active sunspots cool the suns surface at maxma, similar to the way tornados on Earth cool the oceans and currently the dynamo (battery) fuelng this process has slowed down?
If this is the case and the underlying fusion reaction stays constant, could the reduction in strength of electromagnetic generated sunspots be an indication that lower layers of the sun are gettng hotter? This could perhaps lead to more large CME’s and super-flares which are another more destructve coolng mechanism. Could explain why TSI stays fairly constant during the solar cycle despite all the other changes.
“Actually, the problem is not about thermonuclear activity, but on the Coulomb barrier, or potential barrier, which prevents that one proton fuse with another proton. The solution to this problem is quantum tunneling.”
A proton can’t fuse with a proton, ever!
The Coulomb repulsion can only be broken with extra uncharged neutrons to provide enough extra strong force. Thus protons first fuse to neutrons to make deuterium and that gets an extra neutron to make tritium, both of which take energy. One gets paydirt when a 1P1N deuterium smacks into a 1P2N tritium to give 2P2N alpha and a high energy neutron. So the repulsive coulomb force of two protons is outweighed by the combined strong force of five hadrons.
Our Lady of CERN Anna V. could probably explain it better.
A couple of years ago Pontieri et al. published ”A Simple Model for the Solar Cycle”,
http://www.springerlink.com/content/kk9612tt547lpt44/
Let us just assume, for the sake of argument, that their model which is based on the van der Pol equation,
x” + rx'[x²-1] + x = 0,
actually can be used as a fairly good approximation of the 11/22 year nonlinear sun cycle. Then, to summarize the discussion, it must be correct to state that,
1. The 11/22 sun cycle continues even if the visible sun spots disappear.
2. Both the Aurora and the visible and invisible sun spots follow the 11/22 year sun cycle.
3. The Aurora and the visible sun spots are not directly correlated, but each are directly correlated to the underlying 11/22 year sun cycle.
4. If the visible sun spots disappears the Aurora do not need to be weaker or disappear since the underlying 11/22 year sun cycle is always active.
Let us imagine that the sunspots disappear completely the next two decades. We can then conclude that the Aurora will still follow the 11/22 years cycle. This must be a testable prediction.
>>> “givernments”
>>> Is that Freudian?
No, but “takerments” might be…
.
Carsten Arnholm, Norway (02:08:08) :
We should see some evidence of them in the SOHO magnetograms?
We obviously don’t see them on the Magnetograms that look like polished granite, but we sure do see a lot of pootly lit LED’s on the EIT’s.
They like to pop in & out on the images over the course of several days, just like our sought-after L&P’ed activity.
Tenuc (02:35:58) :
Quite. When you boil noodles, you have to stir them, otherwise they boil over.
The sunspot activity must be convective to keep the cauldron stirred and prevent the excessive spitting of CME’s, etc.
Low battery: the magnetics to keep the thing stirred properly are too weak.
TSI: More like a bank balance than a balance sheet. Doesn’t tell you what’s going in and what’s going out, just how much you got or owe.
(warning, anecdote)
I lived in southern Norway in the ’70’s. Don’t remember any aurora at all. As a kid I’d definitely have remembered something as cool as that.
I linked through to that website, it is absolutely ridiculous to say the least.
Oops sorry that comment was meant to be on the balloon article…
3. The Aurora and the visible sun spots are not directly correlated, but each are directly correlated to the underlying 11/22 year sun cycle.
brings up a problem: If they are both correlated to the 11/22 year sun cycle, why would the spots then go down but not the Aurora?
Either the Aurora are exclusively a weak Solar-caused phenomena, or they are caused by both Solar and Extrasolar sources. Opportunity for a test: If there are aurora, and no source found that is solar, then we have a smoking gun for both being causative.