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
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In any case, Phil will bring me to a screeching halt if I am out in left field somewhere.
ChasMod, maybe can cut and paste this all to one post instead of three ?
“givernments”
Is that Freudian?
Looks like an inverted hockey stick to me.
I would disagree that the Sun affects day and night temperatures. That would be Earth’s fault. So many times we fall into thinking that resembles flat Earth thinking. Such as: We have day and then we have night and the Sun determines this. But the Sun always shines. It knows no day versus night. Thus to be more correct, the Sun has no measurable affect on day versus night temperatures.
I propose that we identify all of the excess humans and ask them to stop breathing.
Watch out when someone starts talking about sacrifices. They usually have a knife, and it’s not pointed at themselves.
Pam: If the day comes when L&P does the 3rd possibility, instead of continuing on it’s present downward course or leveling off prior to heading back up, and does a radical plunge to zero, then you shall have your unequivocal test.
Otherwise, there is an eclipse of the Sun at least twice a year with which to take measurements. Alas, they don’t last all day. For that you need Arctic or Antarctic night.
That would be no fun and I don’t wish that on anybody. Well, maybe not everybody.
I comment on this same article on my blog http://solarscience.auditblogs.com/2009/09/03/nasa-on-the-disappearing-sunspots/
The key part is:
Note that of course, they don’t mention that this coincided with the coldest part of the Little Ice Age. But that would be politically incorrect, wouldn’t it?
I note you cover your ass with almost always.
Just stating the facts.
BTW. What’s the best time to record max/min for a given day? (For an experiment, let you know after I’ve finished.)
From what I gather, Tmax is usually a bit after noon and Tmin is usually a bit after midnight. This varies of course, as the wind or any other factor dominating local conditions can cause a sea change at a moment’s notice.
But consider desert conditions as an extreme example. It can get extremely hot during the day but quite cold at night.
NOAA takes this into account and has had to make TOBS bias corrections because the times temperatures were taken had changed over the last century. If day/night measurements were the same there would be no need whatever for those corrections.
There is considerable debate as to the sun’s effect on climate over the long term. But the day/night dichotomy is quite stark.
evanmjones (19:05:41) :
Just a pedantic observation sorry… from someone who has spent many a night sleeping under the stars… the coldest temperatures are normally shortly before dawn, this is true in the tropics, as it is here in the sub tropics, so i suppose its relatively uniform the world over. (o course excluding those times when a mass o warm air moves in)
Overdue for a quiet period. Mean monthly number per 70 years.
[IMG]http://i221.photobucket.com/albums/dd277/shamus1955/mean754.png[/IMG]
Actually, that makes a lot of sense. It also fits in with the sun’s role, as just before dawn is when lack of sunlight is at its longest point.
The output of the sun would have to be changing for it to influence climate over long periods. This is a matter of great and ongoing debate. But the day/night differences are well known and quite indisputable.
Solar activity has been on the downslope since SC21, and now we are heading into the [un-named] Minimum. Wouldn’t you expect a decrease in the overall magnetism of the Sun?
Nothing new going on here in my book.
Sorry, I linked that wrongly- this might work
http://www.woodfortrees.org/plot/sidc-ssn/mean:754
It seems Mr. Watts now should perform an incantation.
Which is disappearing faster: The Arctic Ice or the Sunspots?
The Arctic Ice I cannot see, I can see the Sunspots are not there.
jmrSudbury (17:52:12) : ‘… failed to count more than a few dozen sunspots per year …’
There were 8 in 2008 and 10 so far this year. When will we get up to a few dozen per year? — John M Reynolds
When it happens in their dreams.
tokyoboy (19:40:26) said :
It seems Mr. Watts now should perform an incantation.
Well, I was wrong that Anthony has completely lost his Sunspot Mojo, but it IS pretty clearly in decline. That last Watts Effect spot, poor little weenie pore of a thing, was just sad.
It’s just depressing to see a man’s Mojo petering-out like this.
Maybe we could chip-in and buy one of those pump things like Austin Powers had.
evanmjones (19:05:41) :
“What’s the best time to record max/min for a given day? (For an experiment, let you know after I’ve finished.)”
I’ve noticed on several occasions that summer days tend to reach their highest temperatures around 3:30PM (daylight time). I expect that, similar to MikeE’s comment that min temps tend to be just before dawn, max temps should be after solar noon. My guess is that it varies from 1/2 to 1 hour past noon during winter months to 2 to 2 1/2 hours past (solar) noon during the summer months.
T-max, try mid-to-late afternoon
T-min, try just after dawn
George E. Smith (18:08:23) :
If my memory serves me correctly (and it sometimes doesn’t) when a magnetic field splits the energy levels and results in two different components at slightly different wavelengths those two components are also plane polarized perpendicular to each other, which gives an additional clue that you are seeing a zeeman split, and not some other interloper line (whatever the blazes that might be. There may also be some sorts of three way splits, where a single line calves off an upper and lower pair that are perpendicularly polarized, and equidistant from the original line that remains unpolarized.
Looks good to me George but I have to go a long way back! It depends on the transition being looked at, the simplest gives splitting into a triplet as you described above, because of the different polarisation when viewing a sunspot from directly above the upper and lower lines are visible so a doublet is observed. For some species (Lithium?) the sun’s field is strong enough to get Paschen-Stark splitting which gives even numbers of lines.
NOAA Weather Radio gives T-Min at 5 am at Sea-Tac Airport in their Daily Almanac segment during Daylight Saving Time and 4 am during Standard Time. I’ve started listening for a 6 am or 7 am Min Temp at Sea-Tac that is lower but I haven’t caught them yet. Shouldn’t T-Min be the lowest recorded temp. in the 24 hour day?
MikeE wrote :
“…The only logical solution, is to fire all our nuk’s at mercury in the hope of breaking it free of its orbit and launching it into the sun… which will re fire up the sun …”
Does the sun have external sources of fuel – small though it may be? (Sometimes a comet ends up going into the sun.) How much matter does Its gravitational force pull in per some unit of time? Since the sun is a fusion furnace, any element below iron on the periodic chart should provide it energy.
Michael Ronayne (17:12:19) :NASA actually used the words “Maunder Minimum” for the first time.
Mike Abbott (18:07:21) :Not quite. The search engine on NASA’s home page picks up twenty hits on that term.
Not so sure that’s what Michael meant. You are interpreting that too literally. Of course the term Maunder Minimum comes up everywhere. Google it and you get 70,700 results!!
Poetic license. He was inferring that NASA was actually hinting and juxtaposing the current historic uncertainty regarding the sun….to the uncertainty of that time [can’t say it….you know….the Maunder Minimum….ssshhh!].
Regardless…we as a species need to be prepared, and we are not becuase of the the Gore-Holdren smokescreen. So we know one thing for a fact: our world leaders are clueless.
So, Michael is right…at least NASA is starting to hint and think outside their bureaucratic box!
Chris
Norfolk, VA, USA
We know that to produce magnetic fields, the Sun requires of strong macroscopic electric currents (1). However, we are not sure about what the origin of those macroscopic electrical currents is. Larmor, Steenbeck, Krause and Rädler, and Cowling and Parker attributed the generation of strong electric current to the solar dynamo (2)
A systematic question could be: If sunspots are created by strong magnetic fields and those magnetic fields are generated by macroscopic electric currents, and the latter is generated by the solar dynamo which is continually creating and destroying the solar magnetic fields (3), what could be happening in the Sun’s core during solar minimums? A regular response is that the thermonuclear activity is decreasing. The problem is to find the reason of the decrease of solar activity. If one resort to classical physics, one would be stumble upon many uncertainties. However, quantum mechanics can give explanations based on observations from natural phenomena.
1. Shu, Frank H. The physical universe: an introduction to astronomy. 1982. University Science Books. Sausalito, CA. Page 99.
2. Antia, H. M., Bhatnagar, A. , Ulmschneider, Peter Lectures on solar physics. 2003. Springer-Verlag Berlin. Page 174
3. http://science.nasa.gov/ssl/PAD/solar/solar-b_facts.stm