Talk:List of solar cycles

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I'm guessing that this is minimum to minimum; anyone know for sure? Eassin 18:59, 24 April 2007 (UTC)

Yes, minimum to minimum. Sagittarian Milky Way 02:24, 6 May 2007 (UTC)
No it is not. How do you know, when you are in the minimum. The cycle starts at the end of a minimum, and the beginning of the maximum. This is, when the first spots appear at high latitudes. 14:14, 29 August 2007
What does "beginning of the maximum" mean? The maximum is a point. Do you mean the beginning of the increase of new-cycle spots? That has never been the definition of the transition between cycles, though. The historical definition is the point when new-cycle spots consistently outnumber old-cycle spots. 0nullbinary0 (talk) 21:30, 6 May 2008 (UTC)

Cycle 23 has not ended yet. A cycle is said to have ended when new cycle spots outnumber old cycle spots (polarities are reversed).

...... FROM NASA: "Old Solar Cycle Returns"

March 28, 2008: Solar Cycle 23, how can we miss you if you won't go away?

Barely three months after forecasters announced the beginning of new Solar Cycle 24, old Solar Cycle 23 has returned. (Actually, it never left. Read on.) ...... —Preceding unsigned comment added by (talk) 08:11, 4 May 2008 (UTC)

A question from a very non technical observer. Why do the dates and cycle lengths in the table not match the "Official list of solar cycles" external link at the bottom of the page? (talk) 03:44, 4 August 2012 (UTC)

Standardizing cycles[edit]

I propose that we use the maximum of each cycle. They are easily seen in the Kane reference I've added to the page. Using minimum-to-minimum is very subjective because cycles can be overlap (spots from different cycles coexist in different latitudes at the same time). Additionally, the Space Today reference that was on here previously did not cite its methodology well and, just by looking at the site itself, doesn't seem like a very good source for information. Jason Patton (talk) 16:58, 26 July 2008 (UTC)

The latest edit to this page is perplexing, I shan't edit it but will query the current text. From my reading the official start of a solar cycle is when the number of sunspots of the new cycle outnumber the number of spots in the old cycle.(Using maths to determine precisely this cutover) The time from the first spot till this occurs is usually 1-1.5 years. The reason for this is that sunpsots do not always appear where they ought to, a possible 24 spot appeared back in 2006, so following the logic of the current text cycle 24 began then.

I'm curious if you have a reliable source for the method you've outlined. That would make the article much better and easier to maintain since the precise method could be outlined. We also wouldn't have to deal with overlapping. However, the NASA source cited on the page discusses how two cycles can be ongoing at the same time, so unless you have a better source, we should leave the text concerning cycles 23 and 24 as is. Jason Patton (talk) 20:24, 28 July 2008 (UTC)

Did the editor not notice that in the entire list that nowhere does two cycles overlap? Cycle 24 is not counted as having officially begun until it has surpassed cycle 24 in number. It has begun producing spots but it is not yet reached the point where using the established method it is deemed to have become the current (or preeminient) cycle, that is still cycle 23. So far cycle 24 appears to have produced 3 spots which have lasted for a total of 5 days and a couple of which have been so small that they may well have been not seen in previous centuries. (I had to look mighty hard on my monitor to see them.)It has not produced spots in a couple of months now and it is possible that the spots that have already occured could be another false alarm. (Although unlikely.)

The list was previously based off a source that did not account for overlapping. It did not appear to be a very reliable source, so I updated the source (which still somewhat supports the list), but I don't have the time to go through it and do some original research to figure out where each cycle begins and ends with respect to them overlapping. Jason Patton (talk) 20:24, 28 July 2008 (UTC)

As for using maxima to replace minima, I would have two objections. Firstly minima is the historical method and would mean a disjoint with historical texts. Secondly minima marking the point when spots of a different polarity and in a different part of the sun take over as the preeminent cycle seems more significant. In maxima there is no change of polarity and the spots are midway through there procession across the sun. If that were to be done then at least change the number system (eg Roman numerals or letters) to limit the possible confussion between the two list of cycles.

What is occurring currently is historically significant, no sunspot cycle has run over 12 years for over a century. Futhermore no sunspot cycle which follows a 12 year plus cycle has been over around 100 (with the mean being closer to the 70's). So we already have a significant event in the long cycle but if cycle 24 is as some still predict well over 100 it will be the first such cycle in recorded history and if it is down around 70 it will be the first such cycle in some time. —Preceding unsigned comment added by (talk) 09:43, 28 July 2008 (UTC)

For any other editors that would like a visual to see how cycles can overlap, see: [1]. The tail end of a cycle has spots near the Sun's equator while spots of a new cycle can occur at higher latitudes. Jason Patton (talk) 20:27, 28 July 2008 (UTC)

This article is no longer in line with other Sunspot wikipedia articles, so if your wanting to be as bold as change this one then please change the other articles as well. (eg Sunpsots)

Here is a link with some data but I'll attempt to descibe verbally why your alternations are not appropriate.

The sunspot cycles list goes some back way in history. When it was begun it was not known that the polarity of sunspots changed with each cycle they only looked at the number of sunspots not which cycle a particular spot belonged due to its polarity and position. They measured minimum as the point at which using smoothed average was at a minimum and used that as the start of a new cycle. There is no way now of going back to the beginning of the record and pick out polarity etc of individual sunspots to determine when the first and last sunspots of each cycle occurred. Thus to move to your suggested system of using the appearance of the first sunspot as the beginning of the cycle (in the list of when cycles are numbered from not when we now know they begin) would mean abandoning all data from before polarity etc was known and shortening the list drastically.

Secondly as I pointed out above, sunspots do not always appear and behave as expected and anamalous spots occurr with wrong polarities or in the wrong area and possibly some manage to appear in the wrong hemisphere etc. Spots that may have been cycle 24 occurred before January 2008 but were discounted since the cycle clearly did not take off following them. (As is still a remote possbility with the 3 spots in early 2008) Using individual spots and not a monthly smoothed value to mark the delineation would create issues of when and when not to count a spot.

Thirdly you have the issue of how large a spot justifies being called a spot. Our resolution and ability to pick spots has greatly improved, we now see spots that we once wouldn't have. How large must a spot be before being designated a spot and how would this impact the historic records. 2 of the cycle 24 spots seen so far may well not have large of sufficient magnitude and duration to have been recorded in earlier peroids. Leaving cycle 24 with 1 spot which may have been seen as an outlier not the starting spot of a cycle.

Fouthly, following your logic why not use actual days to mark the cycle and not months. Since we know on what day a particular cycle has begun using your system, why not start listing the cycles on the day the first spot began. Of course this may cause havoc with the ending date as spots from old cycles can pop years after the now current ending date. —Preceding unsigned comment added by (talk) 00:10, 30 July 2008 (UTC)

I agree with a lot of the problems you've pointed out, but what are you suggesting gets done to the list? It would be nice to have a standard definition as to when a cycle starts, but as the article you posted says, there really is no official definition. I'm not suggesting that we necessarily label cycles by when the first spot (of whatever size) appears, but there exist WP:RS that state that cycle 24 has started because they do go by that method. And indeed, I could attempt to label each cycle by the exact start date, but there was no reliable record that I could find that listed when the first spot of each cycle occurred. I might be able to infer an approximate date from some butterfly graphs, but that would be original research. The issues with polarity that you've highlighted might explain why it's so hard to find data detailing the exact starts and ends of cycles, but that doesn't help the article, unfortunately.
Furthermore, I want to ask you what you think about completely redoing the list as a list of sunspot cycle maxima? The date of each cycle's maxima is much clearer and less disputable. At the same time, such a list will probably leave readers unsatisfied. But when I first came by this article, I was also terribly unsatisfied as no methodology for obtaining the list was outlined in the least. I still want to clean it up (hence why I added a cleanup tag), but I'm having a hard time finding sources to give the article the information it needs. Jason Patton (talk) 08:07, 30 July 2008 (UTC)

I have not edited Wikipedia before so I'm unsure about how official a reference has to be, would paragraph 4 of this link: which states that a cycle is min to min be enough. Of course that doesn't yet address the issue of exactly how to ascetain the minimum. —Preceding unsigned comment added by (talk) 09:14, 30 July 2008 (UTC)


It seems like it would make good sense to put this list into a table, showing the maximum, start date, and end date of each cycle, and perhaps any other useful info (total # of spots?). —Preceding unsigned comment added by (talk) 15:14, 16 January 2009 (UTC)

  • Made but please make/suggest improvements Phil (talk) 14:21, 9 April 2009 (UTC)

New cycle[edit]

Wikinews: Sun begins Solar Cycle 24. Wikinews January 2008. --Mr Accountable (talk) 22:55, 1 November 2008 (UTC)

Does this mean that the table can be updated? (talk) 21:59, 13 May 2009 (UTC)

Solar Cycle 23 is still in effect.. What is going on??? -- (talk) 20:41, 1 August 2009 (UTC)

Correction of the table?[edit]

Waht about the following paragraph in solar cycle:

Until recently it was thought that there were 28 cycles in the 309 years between 1699 and 2008, giving an average length of 11.04 years, but recent research has showed that the longest of these (1784-99) seems actually to have been two cycles.. etc, etc,

Shouldn't this article be rewritten correspondingly?Kope (talk) 13:55, 6 September 2009 (UTC)

Solar Cycle 24 now in 2013[edit]

Off topic?

FOX news says/said that would bring 30-50% stronger Solar Flares (I mean auroras) with Earth's weaker magnetofield that would disrupt EHV eletricity of USA and high-power electricity, meaning $2-4 Trillion in damages, nearly erasing virtually-all life in existence on earth. So it was in 2006-2008.

The satelite THEMIS observed the Solar Flares in Solar Cycle 23-24 as NASA said. I didn't know that.

But no, don't let this happen, know nor predict of solar flares that would kill us.

Ahh, Solar Cycle 24 will have less than 90 sunspots to peak in May 2013 but not December 2012 as NASA and NOAA predicted. This would mean Sun's activity will be exhausted. But in 2012, Sun's poles will invert but not the earth's poles. Nothing to worry about it.

Or the Sun will be in the next Maunder Minimum around 2012-2013 or so, keep imagining! —Preceding unsigned comment added by (talk) 07:01, 7 November 2009 (UTC)

Now that we're well into 2013, it appears that the "secondary peak" predicted by NASA is waning (at least according to the Smoothed SSN), and that the Cycle 24 maximum occurred in February 2012 with a maximum smoothed SSN of 66.9. Looking at Wolf's law, the average latitude of sunspots has been less than 15 degrees for a while now, so it seems safe to call the Solar Max. Who makes that call, and when might it happen? Dms422 (talk) 17:21, 1 October 2013 (UTC)

Earlier cycles?[edit]

Sunspot counting goes back to the early 17th century. This graph shows at least three clear cycles before the first one listed here. Even during the Maunder minimum five cycles (listed there) can be extrapolated. So why does the list start in 1755?-- (talk) 18:09, 15 December 2009 (UTC)

table appears to contradict itself[edit]

The last line is saying the cycle began in Dec 2008, but the previous line is including thru Feb 1, 2010. This needs brought in synch. I don't know which is right since they are both sourced. Jon (talk) 16:55, 10 February 2010 (UTC)

My understanding is that at the end and at the beginning of cycles there are several spotless days but none in the middle of cycles. Also, the the starting point of a new cycle is defined as the point when the number of sunspots of the new cycle starts being larger than those of the old one. This separation point was determined as December 2008. But spotless days are still coming for a while, this is why the number in question increases for some time. There is no contradiction in the table. Kope (talk) 20:59, 20 February 2010 (UTC)
Where's the 2008 to current data? Bizzybody (talk) 05:21, 1 November 2012 (UTC)


All the sunspot numbers on this article and the individual articles for each cycle are now obsolete . SIDC (which is responsible for the official International Sunspot Number) has changed all the data [2]. At some point we need to go through all this and update it to the new data [3]. Jozsefs (talk) 15:01, 26 August 2016 (UTC)