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Solar cycle[edit]

It would be nice if people who contributed to this page could also help with the solar cycle (and solar maximum/solar minimum, etc... pages), which really need some extra information. USferdinand 03:13, 16 January 2007 (UTC)

This line: "...and while the observation of a reverse polarity sunspot on 4 January 2008 officially began Cycle 24, no additional sunspots have yet been seen in this cycle." Needs to be updated now that additional sunspots have been sighted - but they are not the right polarity for the new cycle. In light of this - and the fact that cycles do not have definite starting dates anyways - IMHO this reference to Solar Cycle 24 starting on Jan.4 should be removed. —Preceding unsigned comment added by (talk) 15:31, 26 March 2008 (UTC)

Well, maybe not... if you link "Cycle 24" to List of solar cycles, that would explain the reference to anyone who cares to find out about it. I don't think it should be there with no explanation, however. --Tckma (talk) 19:09, 1 April 2009 (UTC)
and it would make sense to introduce the term Schwabe Cycle here, with a link to Solar Variation, as well as the concept of Sunspot Numbers--Richardson mcphillips (talk) 11:45, 10 May 2009 (UTC)


Galileo was blinded late in life by an eye infection; his extensive observations of sunspots were 20 years earlier. The warning against direct observation has been corrected. Dandrake 02:42, Oct 28, 2003 (UTC)

2003 X28 Flare[edit]

I'll go ahead and update the history to include the Nov 4 2003 record-setting X28 flare. Holographic images show there's still amazing activity on the far side of the sun. We'll see in a handful of days what might sweep across the ecliptic when that part of the Sun comes back into view. SEWilco 02:10, 13 Nov 2003 (UTC) co

concnerning the sunspost story a detail review are given in wilfried schröder, das phänomen des polarlichts, darmstadt, wissenschaftliche buchgesellschaft, 1984 (revised version Bremen: 2000)

The politics of the intro[edit]

Tsk tsk, Mr. Poor. The lines you added to the Intro support your politico-scientific views; and so far as I know, what they assert is accurate. But does this really belong in the Intro, where we are trying to say succinctly what sunspots are? Dandrake 18:47, Aug 6, 2004 (UTC)

Where in the cycle[edit]

One of the most obvious questions anyone who knows just a little about sunspots might want to ask is... Where are we in the sunspot cycle at the moment?

Neither this article nor any of the references seem to address this question, since after all, anyone who's reading technical stuff about sunspots would obviously already know!

As best I can tell from the charts included in the article, we're approaching a minima; would someone who actually knows like to confirm this by adding something to the article to this effect?

Seems a fair question. I put it into the intro from one of the refs. I'm not sure if it belongs there. William M. Connolley 21:29, 7 January 2006 (UTC).


The last sentence in the sixth paragraph says "Even the lack of a solar corona during lunar eclipses was noted prior to 1715." Shouldn't it be solar eclipses? RWinther, January 10, 2006, 02:55 (UTC)

Date of first observation[edit]

I think the reference to Gan De observing sunspots in 364 BC should be removed unless we have a better source. On p. 9 of "On Sunspots" by Galileo Galilei & Christoph Scheiner, Translated and Introduced by Eileen Reeves & Albert Van Helden (University of Chicago Press, 2010), the authors state, "Far Eastern observers carefully noted such spots, and records dating back to at least 165 BC have come down to us." This statement cites the following reference: K.K.C Yau and F.R. Stephenson, "A Revised Catalogue of Far Eastern Observations of Sunspots (165 BC to AD 1918)", Quarterly Journal of the Royal Astronomical Society 29 (1988): 175-197. --Doesper (talk) 23:10, 16 June 2012 (UTC)

How certian is the date, 28 BC for the Chinese first observation? Here is a source that gives 170 BC. -MrFizyx 15:31, 14 August 2006 (UTC)

  • This article from the UNESCO Courier cites afew earlier observations and the 28 BC observation, looks like we should go with 4th century BC or 165 BC. -MrFizyx 15:39, 14 August 2006 (UTC)
    • I read your reference (and found others to corroborate it), and agree. Article changed accordingly (and other linked articles will need to be updated, too) DoctorEric (talk) 14:00, 14 July 2010 (UTC)

Event of 1 September 1859[edit]

It would be nice to have some more information on this event, does it have a name? I have heard some fascinating stories about it. Maybe it even deserves its own page, after all, it is the most powerful solar flare in recorded history, it's definitely an important topic. This has major practical importance too because a repeat of this magnetude of solar flare would be devistating.Dru007 01:15, 21 October 2007 (UTC)

August 2008, no sunspot activity for the first time in over a century[edit]

Would it be appropriate to mention somewhere that August 2008 was the first month in over 100 years that no sunspot activity was recorded? —Preceding unsigned comment added by (talk) 01:05, 3 September 2008 (UTC)

Could we see graphs like these? (Sunspots for the last 10,000 years and more)please? —Preceding unsigned comment added by (talk) 18:55, 14 October 2008 (UTC)

20th Century?[edit]

There are sections on the history of sunspots in the "17th & 18th Century," "19th Century," and even "21st Century." It seems odd that there is no section on 20th Century sunspot observation, given the enormous strides in solar observation and understanding thereby gleaned during that time. I'm not an expert in the area, so I'll leave it to another to add the section... DoctorEric (talk) 22:49, 14 July 2010 (UTC)

Early atmosphere[edit]

On 27 November 2010 Hugh Hudson made an edit (in his words, "corrected a probable error") with respect to sunspot effects on the prehistoric earth. The edit may be legit, but "probable" isn't good enough to change an article without a citation from a reliable, scientific source (preferably more recent than the articles from the 1980's cited for the paragraph). I'll check back later and, unless a citation of a scholarly source is forthcoming, will change back to the pre-edit version of the paragraph. DoctorEric (talk) 02:04, 14 February 2011 (UTC)

Sunspots and revolutions[edit]

William M. Connolley thinks that William James Sidis was into astrology. Sidis couldn't even listen to irrational things (like the bible). Read his biography! as I wrote in edit summary: link talks about correlation of ionization from the sun radiation on human mood etc. You can compare this with seasonal affective disorder. Lakinekaki 23:11, 31 January 2006 (UTC)

Nope, I think CarolMoore is [1], whoever she may be. Sidis is probably of historical interest; his theory is junk, because he has it the wrong way round To explain this, I may say that sun spots are rifts in the surface of the sun, exposing a lower layer. This lower layer gives less light and heat than the surface, and therefore, the more spots there are on the sun, the less heat the sun will give, and the cooler will be the climate. However, he's a useful example, so I thank you for providing him! William M. Connolley 23:19, 31 January 2006 (UTC).

I see a quote saying "but new estimates suggest a delay until 2009" but no reference given. Is this along the lines of 'okay, there's no massive evidence of global warming this year...but just wait until next year when the sunspot cycle begins again (even though it's 2 years late by then)!' More in hope than in commonsense? —Preceding unsigned comment added by Go Away White (talkcontribs) 16:43, 19 September 2008 (UTC)

Disk viewer[edit]

I removed someone's claim that a floppy disk can be used to view the sun. Someone have a source that this is indeed safe (and preferably also that it is not an opaque material)? (SEWilco 01:47, 15 August 2006 (UTC))

No, it's not safe. They meant the floppy magnetic stuff on the inside of old-style floppy disks. Again, it's not safe and transmits dangerously high levels of infrared. Sagittarian Milky Way 21:35, 13 June 2007 (UTC)
I think that CD should be safer. Reflecting infrared is requirement for it's function. And CD's are easily available. (although it may take some time to find some without print.)
What about ultraviolet, huh? Don't do that stuff. Just get eclipse shades that cost a few dollars. They probably even give them out for free if your area's having a major eclipse. Sagittarian Milky Way 18:35, 5 November 2007 (UTC)

Regarding the second photo up: I see no reason to believe that's an actual sunspot, instead of the much more likely lens or digital chip dust-bunny. 16:05, 1 October 2007 (UTC)Ubiquitousnewt


Similar phenomena observed on stars other than the Sun are commonly called starspots. - do we really have the rez to see them on other stars? William M. Connolley 08:23, 28 October 2006 (UTC)

We can see changes in the brightness of other stars that are interpreted to be caused by spots. Dragons flight 19:51, 28 October 2006 (UTC)
OK, I thought it might be something like that. But the text seems misleading as written (not to mention unsourced) William M. Connolley 20:03, 28 October 2006 (UTC)
I have added Strassmeier as a source, and the already-referenced Svetlana Berdyugina's comprehensive review of methods and results contains many references to starspots in the literature. This gallery has some interesting "images" of starspots. -Wikianon (talk) 00:29, 20 February 2008 (UTC)

sunspot temperatures[edit]

I'm no expert but the listed temperatures are low compared to standard sources (e.g., Allen's astrophysical quantites; Ostlie+Carroll; Zirker) which quote 4000 K

  • Not only that, but the article also says "umbra (temperatures around 2200 °C), penumbra (temperatures around 3000 °C)." Yet in the intro, it says they're between 4000 and 4500K. I'm no expert either, but I do know that there's a big difference between 3000C and 4000K... --TheSlyFox 07:48, 29 January 2007 (UTC)

Sunspots appear darker (relative to the unaffected areas of the sun) in the visible spectrum, however in the ultraviolet and higher frequency spectra they appear to be very much brighter. (Source - "The Sun" a one hour British science documentary shown on SBS television, Australia, March 18, 20:30).

This would seem to indicate that the emitted radiation has increased from the visible frequency band to a higher-energy band. This is consistent with an INCREASE in temperature. DrBob127 23:35, 19 March 2007 (UTC)

  • Ok, if no-one is going to offer a differing viewpoint, then I am going to change the introduction to reflect the fact that sunspots are not cooler but in fact hotter than the surrounding area (with appropriate references of course) DrBob127 02:24, 29 March 2007 (UTC)
Ok, I was wrong, sunspots are cooler despite emitting higher energy radiation. DrBob127 02:43, 29 March 2007 (UTC)


"Although they are at temperatures of roughly 5,000–6,500 K, the contrast with the surrounding material at about 5,800 K leaves them clearly visible as dark spots"

This makes no sense.

Sunspots are cooler than the surrounding photosphere. Hence they're dark. Becauyse relative to the surrounding area, they don't emit as much radiation.

The surface of the sun is approximately 5500K (the Sun article quotes it as being 5,780 K, and it would probably wise to be consistent within articles). Sunspot temperatures can be in the region of 3000-4000K, as noted by Wallace et al (Science, Vol 268, pp1155, 26 May 1995).

Any objections? --InvaderXan (talk) 18:47, 11 November 2009 (UTC)

Sunspot life cycle[edit]

Is it worth mentioning the life cycle of a sunspot? I.e. that they are born at the equator and die at the poles? Jamie 10:37, 5 January 2007 (UTC)


potentially affecting airline flights, communications satellites and electrical transmissions.

can it happen what the article says? Phu2734 11:44, 28 April 2007 (UTC)

Recent info NOAA[edit]

Very informative. Answers to a lot of these questions

Removed from "Significant events"[edit]

I've removed the following from "Significant events":

In August 2008, a NOAA observatory reported only a half-sunspot, and another reported zero sunspots. The former had not happened in fifty years, and the latter in a hundred.

The reference was Sun Makes History: First Spotless Month in a Century (DailyTech).

It isn't that significant, really--the rate of sunspot production varies naturally over long periods of time. There were five sunspot groups in October, and four of these were from Cycle 24. This is uncharacteristic of recent cycle transitions but not a significant deviation from normal, according to David Hathaway of NASA [2]. -- (talk) 09:46, 12 November 2008 (UTC)

cycle 24 has started[edit]

see paragraph 2 needs to be updated (talk) 07:42, 14 November 2008 (UTC)

On reflection I've removed the "Latest events" section. It's more like a news item than encyclopedic content. The significance of the delay in the rise of sunspot activity is a cause of some discussion by solar scientists but the length of the trough appears to be well within historic levels. --TS 17:28, 20 August 2009 (UTC)

Sunspots and Human Ecology[edit]

I removed information about cycles in peace and geomagnetic storms from this section primarily because the reference was shoddy at best. It was a secondary source citing a journal called "Cycles" that I couldn't find any reference to online. I also couldn't find any reference to that paper outside of this page and the linked reference. Even if the reference were legitimate, I also wouldn't be comfortable putting that information on this page, because it didn't look like particularly good research. I went looking for the paper to see how they calculated a "0.008 probability" of such a correlation but couldn't find the full reference as I already mentioned.

If it is decided that we should put back the section I removed, the wording definitely needs to be changed as it was very misleading. For one thing, I would choose to call it a 0.8% chance of happening (which means that such correlations exist by chance 1 in 100 times) or leave that part of it out entirely. If you think about it, given that the guy (presumably very reputable-seeming individual) was probably mining for correlations, for every 100 correlations he checks, he'll find one of these "long shot" correlations - even if he is checking ONLY things that have no correlation.

I also take some issue with other citations from "Scientific Frontiers" (there's another citation in the same section regarding influenza) since it seems like a secondary rather than a primary source (and it also seems like a collection of articles from disreputable journals), so I might go through and either replace Scientific Frontiers references with more reputable sources or delete information that I can't find corroboration for. 0x0077BE (talk) 20:57, 28 January 2009 (UTC)

The information about life-span and sun-spot cycles is highly speculative, derived from a very small sample size and is probably a statistical aberration. Also the two references actually reference the same study. As I am not an expert on the subject, I will refrain from editing... but this nonsense should either be removed or it should be explained that is speculative trivia. Ve2dc (talk) 21:14, 20 May 2009 (UTC)

I've removed the section on human ecology. This is fringe science at best. --TS 17:19, 20 August 2009 (UTC)


I've removed this from the section "Application":

This theory has been around a long time. John Mauchly, professor of physics at Ursinus College, worked for several years in the late 1930’s developing a digital electronic computing machine to test the theory that solar fluctuations, sun spots in particular, correlate with and affect our weather. In 1941, he left Ursinus to work at the University of Pennsylvania. There his computer experience led him, with Presper Eckert, to develop ENIAC, the first digital electronic computing machine, ancestor of the billions of computers in use today.

The story of ENIAC is well known. The rest (which is applicable to this article) is unsourced. --TS 23:48, 1 September 2009 (UTC)

"Depth" of sunspots[edit]

An anon recently added an external link that suggests that the "depth" of sunspots (relative to what?) has been estimated from solar simulations as 1500 km. The link contains no useful information for checking up on this, but it did make me wonder about how deep the sunspot-associated convection went. If there's a sensible point here, it might be worth adding something to the article. I'll leave the external link in as a place-holder for now, although as it's close to content-free, it should really be deleted. Cheers, --PLUMBAGO 07:51, 22 September 2009 (UTC)

I've removed it. There's a bit of a spamming campaign going on with that site. - MrOllie (talk) 11:46, 28 September 2009 (UTC)
That was my thought too, but the site does seem to be reporting on genuine science stories. I thought that there might be some underlying information about stellar convection that could be added to the article. In the ocean, convection is constrained (in part) by seafloor bathymetry, but there's no equivalent inside stars. If there's a story here, it'd be nice to add it - at least to give a more complete description of the structure of the spots. Cheers, --PLUMBAGO 06:40, 29 September 2009 (UTC)
I agree with Plumbago. If there really is something to the "depth" of sunspots, I want to know more about it. How deep? Why? How are the measured? Etc. I did some Google Books searches and found some interesting books devoted to sunspots and how they form during "cyclic convection cells ...". This same book states that sunspots can have a diameter as large as 50,000 km, but I couldn't find anything about their depth. It is a start. --Thorwald (talk) 01:09, 30 September 2009 (UTC)

Sunspot temperatures (again)[edit]

Do we have any simple, accessible, reliable sources on sunspot temperatures. I know they're supposed to be thousands of kelvin lower than the sun surface temperature, but a quick google doesn't come up with anything snappy.

What prompts this? Well recently somebody altered the estimate from "roughly 4,000–4,500 K" to "roughly 5,000–6,500 K" and so I went searching in the article for sources. Finding no obvious references I then searched quickly elsewhere.

It occurs to me that our article needs to say unequivocally what the solar scientists think they know about sunspot temperatures, so if estimates can vary from the first one to the second one (two disjoint ranges) then we should not be precise, and in any case we should provide a readily available reference. --TS 02:08, 30 September 2009 (UTC)

  • What about using this paper (, which states an average photosphere temperature, a range of reduced temperatures for sunspots, and that fact that is faculae (bright spots associated with sunspots) that are brighter and thus 'several hundred degrees Kelvin' hotter then the average photosphere, and thus are responsible for the overall radiation from the Sun being greater. The paper looks official, however im not sure if its a peer reviewed paper or not. It also doesnt reference where these temperatures came from..-- (talk) 11:23, 2 September 2010 (UTC)

Negative sunspot number?[edit]

The graph [[3]] showing a long term reconstruction of the sunspot number shows the number going below zero, is anyone able to justify this? --Damorbel (talk) 06:51, 16 June 2010 (UTC)

"Sunspot" as an undefined concept[edit]

The article refers to sunspots as discrete entities that can be counted. The first photo makes clear that this notion is problematic: the shading features vary in size, shape, intensity, and proximity, ranging down to the limit of visibility, and a more powerful telescope would reveal many more. There could be anywhere from two to eight sunspots in the photo depending on one's criteria for size, shape, intensity, and proximity.

In order to make sense of the notion of counting sunspots one would have to define when a feature was sufficiently large and distinct to constitute a sunspot, when to count a sufficiently tightly packed clump of spots of varying size and shape as one spot (proximity), and so on. Why does the article say nothing about this?

This is particularly relevant to the question of the significance of the Maunder Minimum. In the absence of a definition of sunspot, how do we know whether this was a genuine physical phenomenon or merely a consequence of that century's astronomers applying different criteria for when to count something as a sunspot? One could easily imagine them recording the article's first photo as containing just a single region of significant activity. The article mentions the issues of lack of observational data and negative observations, but not that of definition of the concept.

As a numerical measure of solar activity, counting sunspots instead of integrating their intensity would appear to have all the drawbacks of counting the zero crossings in a time series instead of computing its variance. If it's done because it's the traditional thing to do then that's fine, but in that case shouldn't the article say something about the underlying assumptions and drawbacks of this traditional metric? --Vaughan Pratt (talk) 17:22, 12 November 2010 (UTC)

One major advantage of sunspot number is that there are historical observations of it that go a long way back in time. You're absolutely right that the exact boundaries of a sunspot are somewhat arbitrary, but there are modern methods of correcting for the effects of observing conditions and the like - that's referenced plenty of times in this article in the form of the Wolf number. Eteq (talk) 22:56, 27 May 2012 (UTC)

Recent changes need undoing[edit]

I will try to revert to the article as of Nov. 7, but this may be beyond my Wiki skills to some extent. Most of what has been added in the last few edits makes very little sense and is outside ordinary thinking. The authors of this material should publish somewhere else, since Wikipedia should reflect consensus views as best it can.

Hugh Hudson (talk) 16:01, 15 November 2010 (UTC)

OK, that was easy[edit]

I will check back later on to see what happens, since this is my first experience at a reversion. I actually am the author of a related article on Scholarpedia, in case anybody wishes to check: [4]. —Preceding unsigned comment added by Hugh Hudson (talkcontribs) 16:17, 15 November 2010 (UTC)

reference to Global Warming Swindle film[edit]

The addition of one of the ideas advanced in a polemical film, which does not have support from the scientific community, is too fringe-y to include in this article, IMHO. If User:Taurusthecat wants to add it, can he/she give reasons why it is notable and within the scope of this article, using reliable sources? Thanks, Squiddy | (squirt ink?) 14:01, 7 January 2011 (UTC)

Squiddy, I have been accused by you in a private message of "mindlessly re-posting" the mentioned section within the 'application' section on the sunspot page, however you could equally be accused of "mindlessly deleting" it. The text you keep deleting is relevant to the topic of sunspots, a sizeable portion of the scientific community holds the belief that sunspots do indeed contribute to global warming. Therefore the 'application' section on the sunspot page is the correct and relevant place to put this cross-reference to further information for the reader as it refers to how sunspots have been reported to affect this planet, whether you personally hold this view or not. Wikipedia is made great precisely because of the ability to click through links from one topic/page to another topic/page and for the benefit of a reader coming to the sunspot page, it is in their interests to see as much relevant cross reference material to this topic as is possible. The fact that you and a handful of others do not personally hold the view that sunspots have anything to do with global warming is completely irrelevant, and Wikipedia does not exist to hold personal viewpoints, only impartial and accurate reference material. Further, when you continue to delete this entry (to the detriment of the greater Wikipedia community at large) purely because you don't agree with it personally, it becomes a matter of censorship-with-a-view-to-withhold-information-from-the-public-for-personal-gain-or-reason and is unacceptable not only to the terms of use of Wikipedia, but also the greater internet domain. The entry you keep deleting is based on fact, does not hold any personal view and is also of good use to a reader to allow them to become more informed on the topic of sunspots, regardless of whether you personally agree with the direction this entry goes in or not. The entry being put there does not reflect my personal view on sunspots and global warming, only directs an interested reader to further information, however your deletion of said entry does indeed impose your own personal view on the reader as it removes their ability to learn more purely because you personally don't think they should know about it. That is censorship and that is unacceptable. The entry you keep deleting is of use to a reader as it provides further relevant information on what the scientific community believes is connected to sunspots, so should be left there and not deleted any further. Taurusthecat (talk) 00:31, 22 January 2011 (UTC)

The film is not about sunspots. In a film over an hour long, there is a section less than ten minutes long about sunspots and solar variation, mostly about solar variation. The scientist whose work was used in this section, Eigil Friis-Christensen, later complained that the film had used 'fabricated data.'
This isn't a useful place to point people interested in sunspots, and attempting to use this article as a WP:COATRACK for polemic doesn't improve it. Squiddy | (squirt ink?) 14:04, 22 January 2011 (UTC)

Taurus, I have reverted this again. The Wikipedia article on sunspots should be about sunspots. Global warming issues have their own places in this system. In my view Sunspots should stick with our basic understanding of spots as physical phenomena. Of course there is room for cultural matters (e.g. Galileo or his British predecessor on the history side) but an acknowledged polemic on television doesn't qualify as scientific discourse. But, thanks for finally joining the discussion. -- Hugh Hudson (talk) 12:29, 23 January 2011 (UTC)

I agree. This article should be on sunspots, and sunspots only. There are plenty of other articles for the debate on Climate Change (aka Global Warming). --Thorwald (talk) 19:14, 23 January 2011 (UTC)

Adding the effects of sunspots to this article is valid. It is preferable to use a different source though. The documentary is subject of a polemic and justly or unjustly regarded as controversial. Jan Arkesteijn (talk) 13:25, 24 January 2011 (UTC)

There's no reason not to have cultural aspects of sunspots in the article, but it is a fine point. Sunspots themselves are not what produce effects on the Earth - that we know very well indeed from the observational work. What might have effects, and inspire television programs like the one that we keep reverting the link to, is much more complicated and less well understood. The present article needs a lot of work and has other features that are just as flaky and irrelevant to the physics of sunspots. The article needs the attention of a sunspot expert and better scientific focus, I'm afraid. I hope to make improvements later myself.

Hugh Hudson (talk) 21:24, 24 January 2011 (UTC)

Just as many thousands of other Wikipedia pages contain links to related information pertaining to the source topic, why should the Sunspot page be any different? The text in question purely states that the film (and whether the film is controversial or not is irrelevant) proposed that sunspot acitivty was the main naturally-occurring cause of global warming and the text then links a reader to an existing Wikipedia page elsewhere on this. The text inserted has no doubt and is factual, because this is what the film proposed. Whether the proposition itself is proven, accurate or popular or not has no bearing on this. If an interested reader chooses to click through to the film's Wikipedia page they can easily see how controversial it is anyway. The page on the film is where discussion on it's scientific merits should take place, not here. The fact that a well-known film which has become part of mainstream culture mentions sunspots and sunspot activity as it's main content certainly justifies it to be included on the sunspot page itself. It's like having a page on diamonds and not being able to click through to famous diamonds of note in history or places where diamonds are mined or diamond curses or whatever. From the one page you can go in all directions, and the sunspot page needs to reflect the same thing where Wikipedia is concerned. When you are on a Wikipedia page it shuld contain ALL relevant cross information to that subject and as the film makes a proposition about sunpsots, I can't see why the fuss about having it referenced on the sunspot page. Taurusthecat (talk) 07:20, 25 January 2011 (UTC)

No, actually. You're dead wrong when you say "a Wikipedia page ... shuld contain ALL relevant cross information to that subject". There is a tendency for articles to grow pointless pop-culture references: 'mentioned in Simpsons episode 115', 'Slayer did a song about...', and these need pruning out to keep articles focussed on their topics rather than turning into big fuzzy collections of random shite. Squiddy | (squirt ink?) 10:19, 25 January 2011 (UTC)

This seems to be turning into verbal arm wrestling. Taurus, if It is not true, there is no place for it in this article. The only thing you can do is check publications about the subject. A simple Google search for instance, led me to although It is rather old, so I don't know if it is superceded by more recent research. Jan Arkesteijn (talk) 18:57, 25 January 2011 (UTC)

I've put in a new version of the relevant section, with lots of links that avoid polemics.Taurus is right, there is no reason not to have links to this kind of application of sunspot behavior, and the rest of us are right that the link should not be to something tendentious. In a technical article like this I think it is important to stick with real information, rather than opinion. I would have linked my own article if I could have figured out the syntax, but the present version looks pretty good to me. Hugh Hudson (talk) 03:53, 27 January 2011 (UTC)

Thanks, Hugh. I added the link to your article, although it's content does not seem to reflect your contribution here. Am I right about that? Secondly, I have the feeling that the last two sentences contradict each other. Could you please explain? Jan Arkesteijn (talk) 10:03, 27 January 2011 (UTC)

Thank you! I think maybe we're converging on a good approach here. You are right, the reference to my article is not exactly the right thing, so I will try to patch this up later. The sunspots themselves are irrelevant to climate more or less on basic principles; things related to sunspots (faculae and the "active network") are what make the Sun a little brighter during sunspot maximum. These things can happen without any sunspots being present, so giving the impression that sunspots actually have an effect is misleading. All of the phenomena are produced by the magnetic field, so this is what should be blamed. Hugh Hudson (talk) 05:43, 28 January 2011 (UTC)

I added a string of text from your answer to the article, but I don't understand though. Jack Eddy found a correlation between sunspots and the climate. You say that the phenomena that caused the climate change are not related to sunspots, meaning there is no correlation. Then what did Jack Eddy find? Jan Arkesteijn (talk) 10:38, 28 January 2011 (UTC)

I think what you've got there is OK. There certainly is a correlation on long time scales, in the sense that the TSI variation has an 11-year period just like the sunspot occurrence. But in detail the faculae don't match one-to-one with spots. It is interesting that the faculae are the dominant term on longer time scales, ie that as the spots (dark) get more numerous the Sun actually gets brighter; apparently for other stars the opposite can be true, and it depends upon the age and rotation rate of the star.Hugh Hudson (talk) 20:37, 28 January 2011 (UTC)

Maybe you should rephrase it then, Hugh. It is unclear the way it is. As I read it now it says climate and sunspots are correlate, sunspots are colder though, but at the same time climate is heated while the sun is hotter because of other phenomena which are not correlated to sunspots. Therefore climate is not correlated to sunspots... Jan Arkesteijn (talk) —Preceding undated comment added 12:52, 29 January 2011 (UTC).

Sunspot temperatures (conversion into degrees Celsius)[edit]

The conversion of the colour temperature range of sunspots into degrees Celsius is unduly precise. (That is, because the figures in kelvin are only given to two significant figures, giving the same data in Celsius to four significant figures is misleading and, in my opinion, wrong.) I tried to round the figures to two significant figures, but it seems to have been implemented by some sort of conversion macro. Does anyone know how to enforce a specific precision? Thanks -- Roberdin (talk) 20:40, 8 April 2011 (UTC)

Rounding is not a correct solution. If an author says that a temperature is 3,500 K (rounded to two significant figures), he actually says the temperature is 3,500 ± 50 K. Converted to Celsius it should then say 3,230 ± 47 °C. But rounding the temperature to 3,200 °C would mean 3,200 ± 50 °C, which introduces a deviation in the mean and error from the original temperature. Jan Arkesteijn (talk) 14:07, 9 April 2011 (UTC)
However, in its present form, the article suggests that the temperature range is "exactly" (to four significant figures) "2,727–4,227 °C", with an implied error of 0.5 degrees -- surely this is less correct than rounding. From the context, it is clear that this is not the case, but some people may misapprehend, perhaps taking it out of context, and assume it is a far more precise range than it is, whereas some people (like me) find it aesthetically displeasing. If we put 3,230 degrees, this implies an error of no more than ± 5 degrees. I believe that it would also be improper to state that the error is explicitly 47 degrees C, because the author has not explicitly stated this error on the original data, and it is a range anyway. What do you suggest? -- (talk) 18:01, 11 April 2011 (UTC)
I agree, there are pro's and con's for both views. BTW, I don't see how you derive "2,727–4,227 °C, with an implied error of 0.5 degrees" from 3,230 ± 47 °C. I have no further suggestions, I only feel it's not right to introduce an extra error for the sake of conversion. Jan Arkesteijn (talk) 07:35, 13 April 2011 (UTC)
Not necessary to worry about the C conversion. It's in brackets, it's clear that degrees K is the cited figure and that the conversion is derived naively. Barsoomian (talk) 06:59, 16 June 2011 (UTC)

Sunspots' behavior and reference systems[edit]

Why "the details of their apparent motion could not be readily explained except in the heliocentric system of Copernicus"? (17th &18th Century) The Earth in the center and the Sun around it, like in the geocentric model, still the sunspots should behave like as the Sun in the center, should not they? In other words, sunspots' apparent motion on the surface of the Sun should not be a matter of system of reference. (talk) 19:51, 16 January 2012 (UTC)

Attenuation filters[edit]

This text in Sunspot#Sunspot_observation: "Special purpose hydrogen-alpha narrow bandpass filters as well as aluminum coated glass attenuation filters (which have the appearance of mirrors due to their extremely high optical density) on the front of a telescope provide safe observation through the eyepiece."

It doesn't make sense to me that high optical density (= absorbance) would make the filter have the appearance of a mirror. If it attenuates mainly by absorbtion, it would not look like a mirror. If it mainly reflects (as mirrors do), it is not because of high optical density but because of high reflectivity. Mats Löfdahl (talk) 10:14, 13 December 2012 (UTC)

BCE vs. BC[edit]

Should this article use "BCE" instead of "BC" with respect to dates before the common era, since this is an astronomy subject (and that is the convention)? Yes. I know all about WP:DATES and other WP-conventions about "first use", etc. However, I think a good case could be made for using "BCE" in all astronomy-related articles. Thoughts? --Thorwald (talk) 01:18, 15 January 2013 (UTC)


Diagram with emphasized peak groups:
Basic version:
The state oscillation with an 11 year cycle gets very visible.
--Alexander.stohr (talk) 17:14, 14 April 2013 (UTC)

Why are Sunspots black?[edit]

Sunspots appear dark or black presumably because they don't radiate in the visible light spectrum. Do they radiate at some other wavelength, e.g., microwave or x-ray? Or, are they black simply because they're deep holes in the face of the Sun? Virgil H. Soule (talk) 11:47, 10 July 2013 (UTC)

Sunspots, rather than black, are just darker than the rest of the sun. (this is because the magnetically induced downdraft prevents the heat/energy from rising up in that area, making it cooler. The rest of the sun simply outshines the spot, like it does to all the other not as bright things in the day time. That said, sunspots do tend to radiate more than the solar average in the UV range. Darryl from Mars (talk) 02:00, 31 July 2014 (UTC)

Counting sunspots on the far side of the sun[edit]

I think it would aid the article to explain if old counts were as accurate as modern counts. Now we can now shoot beams through the sun from earth and send satellites to the far side of the sun. I do know that the earth rotates around the sun and that the sun rotates also, but I do not know the answer to my question: can we detect more sunspots than our forefathers could? Fotoguzzi (talk) 22:41, 25 November 2013 (UTC)


The article at contains information which, if correct, should be incorporated into the article. But it should first be verified by other sources.

For example, regarding mythological interpretations of sunspots it says: For ancient Africans living on the Zambezi River, sunspots were mud spattered in the face of the sun by a jealous moon. Is this true? If so it belongs in the "Early Observations" section.

Regarding early Western interpretations it says, Astronomer William Herschel believed they were portholes into a dark subsolar world where people lived beneath the sun's radiant sheath. I have my doubts. Did Herschel really "believe" that or would it be more accurate to say he "speculated" it?

I don't currently have time to look into this myself. Offering it here for anyone who wants to pursue the matter. (talk) 02:09, 31 March 2015 (UTC)

Restructure proposal[edit]



22-year cycle[edit]

A 22-cycle is mentioned only as a hypothesis from 1908. I heard an astronomer on the radio saying that it is now generally accepted that the physical cycle has 22 years. I know nothing about this, but someone who does should track down a reference or two and mention it. Zerotalk 03:37, 7 November 2015 (UTC)

This subject is already discussed, referenced, and wikilinked in [5]. The 22-year cycle is the solar dynamo cycle and the corresponding sunspot cycle (with change in polarity) is known as the "Hale cycle". Isambard Kingdom (talk) 15:28, 7 November 2015 (UTC)
I don't know where you are looking. In Sunspot#Period, the only mention of a 22-year cycle is "Hale suggested that the sunspot cycle period is 22 years.." with a citation to an article from 1908. The word "dynamo" doesn't occur in the whole article. Zerotalk 01:51, 8 November 2015 (UTC)
I apologize for not being very clear. See Babcock Model linked in that section, though you might find this kind of technical. Isambard Kingdom (talk) 02:12, 8 November 2015 (UTC)
And by the way, the 1908 paper by Hale is very nice. I often recommend reading classic old papers. Isambard Kingdom (talk) 02:19, 8 November 2015 (UTC)

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