Monday, July 06, 2009

Who named the Maunder Minimum?

Jack Eddy died recently. Numerous articles and obituaries have credited him with discovering, and christening as "the Maunder Minimum" the period 1645-1715 when virtually no sunspots were seen (here is Nature, Telegraph, Wikipedia). The conventional wisdom seems to be that the historical sunspot data was vaguely known but not widely accepted, until he came along, proved it really happened and coined the name "Maunder Minimum" in his 1976 paper. But is this really true? One of my sources suggested recently that there may be more to this story that meets the eye. He was an active researcher in this area at the time (and remains so) and says he remembers the term as being in widespread use prior to that paper. He even used the term himself in 1977 as if it were a well known expression. So I did a bit of investigation.

Let's look first at the conventional wisdom. Eg from the Telegraph's obit:

"While many contemporary scientists were sceptical about the reliability of these observations, Eddy reinvestigated sunspots in the light of Spörer's and Maunder's work, and concluded that every two centuries or so there was an interruption to the 11-year cycle. He christened the period 1645-1715 "the Maunder Minimum". "

And Wikipedia:

"he identified a 70-year period from 1645 to 1715 as a time when solar activity all but stopped. [...] which he called the Maunder Minimum"

(the MM page also repeatedly credits him with its discovery)

Now, Eddy himself certainly acknowledged (in an interview with Spencer Weart) that other scientists (specifically Maunder and Spörer) had known about the sunspot data, but argued that "in science the proper credit for something goes not necessarily to the first person who thinks of it, or writes about it but to the one who can convince his colleagues and the doubting world that it's true". However, he very specifically claims the name as his own:

"I also, deliberately chose the title of the paper in Science, calling it simply the "The Maunder Minimum." I knew nobody would know what that was."

I was therefore rather surprised to find that a simple google search finds the term "Maunder Minimum" used no fewer than three times in the Introduction to a conference proceedings, dating from August 1975 - almost a full year before the famous Science paper appeared. Indeed, the author of this article (E. N. Parker) refers precisely to the 1645-1715 interval as "the 70 year minimum (sometimes called the Maunder Minimum)" without any attribution or other hint that this might have been a recent neologism. He also refers to coronal and auroral observations which back up the sunspot evidence for anomalous solar behaviour at this time. Eddy was not at this meeting but a colleague of his from NCAR (Gilman) did attend and even has a brief comment, following the Introduction, which refers to some of his work with Eddy concerning the sun's rotation rate at around that same period. There are no formal references to any work by Eddy anywhere in the entire conference proceedings that I can find.

It gets curiouser. In the same interview with Weart, Eddy specifically credits Gene Parker with introducing him to Maunder's work - this is the very same E. (Eugene) N. Parker who gave that introductory presentation in 1975 and talked about "the 70 year minimum (sometimes called the Maunder Minimum)". Contrary to Eddy's claim, I'm sure that Parker, and all the other scientists at that conference, would have known exactly what "The Maunder Minimum" referred to when Eddy's paper appeared!

None of this is intended to belittle Eddy's contribution of linking the sunspots to other data and putting it all on a firmer footing. But it seems clear that the basic phenomenon - and the name - was fairly well known (at least in the relevant research community) prior to his paper. Perhaps the story has grown a little during the numerous retellings on the after-dinner circuit he seems to have enjoyed. I think it may be time for a bit of Wikipedia editing...

I haven't found an earlier ref than 1975 to the "Maunder Minimum", but I am equipped with nothing more than google, so maybe someone else can do better...(I did see a dodgy ref in 1968 in German but it seems to be a typo).

Update 7/07/09

I hadn't bothered to click on it as I has assumed it must post-date the famous 1976 paper, but in fact this paper by Eddy, Gilman and Trotter "Solar rotation during the Maunder Minimum" predates the famous Science paper by several months! Dated Jan 1976 (only submitted Dec 1975 - how's that for a fast turnaround) it refers to Eddy 1976 as being in press.

It is also notable that in the 1976 paper, Eddy specifically christens the Spörer minimum (1460-1550) with the phrases "The earlier minimum, which we may call the Spörer minimum" and "which I have called the Spörer minimum". It is pretty clear that he named the Spörer minimum, and this contrasts strongly with the manner in which he refers to the Maunder minimum.


Brian said...

Okay, I fixed the MM wiki page.

crandles said...

So when was the famous 1976 paper first submitted for peer review?

James Annan said...


It doesn't say, but first dibs goes to the first published record anyway, which (as things stand currently) is Parker in 1975 referring to it as an established term. It is striking that in the famous paper Eddy quite explicitly christens the Sporer minimum, not once but twice, and refers to the MM without any suggestion that it is new.


Wonder how long it will last :-)

Alastair said...

In your quote:

'I also, deliberately chose the title of the paper in Science, calling it simply the "The Maunder Minimum." I knew nobody would know what that was.'

Eddy does not claim he is inventing the name, only choosing it. And when he says "nobody" he should be allowed some artistic licence. The average Science reader would not have heard of Maunder Minimum, a specialist term from another specialty.

I doubt that he claimed to invent either Sporer or Maunder. They were just the epithets used for those two minima. He selected Maunder Minimum because of its alliteration.

Cheers, Alastair.

Marion Delgado said...


I named your note and link

"Who named the Maunder Minimum?"

James Annan said...


From the wording, it is quite clear that he was coining "Spörer minimum" as a new name. In contrast, it seems that MM was already a reasonably common epithet, he had no choice in the matter.

Alastair said...


There is a book here "Assessing Climate Change" at: which goes into Eddy's work quite well.

It was Spörer who first pointed out the Maunder Minimum at the end of the 19th Century, [See 4.3.6 in book] and Maunder repeated his work at the beginning of the 20th Century.

I seem to recall that Eddy should have called it the Spörer Minimum, but MM was more catchy so he chose that name. He seems to have tried to put things right by naming the earlier minimum after Spörer but I doubt that S had identified that one.

The LIA included both.

I think you will find that Spörer and Maunder's work was ignored by everyone until Eddy took an interest. In the fifties and sixties, anyone who said that the little black dots on the sun could change the weather was regarded as crazy.

That is why Eddy's work is so remarkable.

Alastair said...

"[In accord with Stigler's Law of Eponymy, Spörer was the person who discovered the Maunder Minimum; and Spörer's Law was actually discovered by R. C. Carrington (according to Wikipedia).]" From Too Many "Friedrich Wilhelms" at:

Cheers, Alastair.

James Annan said...


Did you actually read my post, and the linked documents?

Eddy was specifically pointed in the direction of the MM by Parker (Eddy acknowledges this in the paper itself, as well as interviews. Parker refers to "the 70 year minimum (sometimes called the Maunder Minimum)" a year before Eddy's famous paper was published.

Far from the MM being being ignored, Parker said in 1975:
"The general point that I want to make here is that we must search over a wide range of possibilities if we are ever to develop an understanding of what was happening at the Sun during the Maunder minimum" It seems very clear that the period was already recognised (and under that name) and under active study by several people at that time.

James Annan said...


I have just noticed that the Science paper also refers to the Jan 1976 Solar Physics paper as "in press" (it's ref 12). So these must have been pretty much contemporaneous. It is also clear from other papers that the actual publication of the Jan Solar Physics could hardly have been in January itself, as one paper was submitted on the 26th or something like that.

Probably some adjustments were made in the review stage, as it is hard to see how both could have been submitted in their final forms!

Unknown said...

Edward Walter Maunder (April 12, 1851 – March 21, 1928) was an English astronomer best remembered for his study of sunspots and the solar magnetic cycle that led to his identification of the period from 1645 to 1715 that is now known as the Maunder Minimum.

Michael Ronayne said...

While I am sure that endless speculation without a single real fact can be very entreating for those with too much time on their hands, this issue can be quickly resolved by two very simple searches in Google School:

Google Scholar: “Maunder Minimum”, before 1976

Google Scholar: “Maunder Minimum”, after 1975

Google Scholar found 11 references to paper published before 1976 that used the term “Maunder Minimum”. Of these 11 references 10 were false positives and the eleventh was this paper:

Eddy JA, 1975. Maunder Minimum - when the sun lost its spots. EOS, Transactions of the American Geophysical Union, 56: 1005.

In 1975 Dr. Eddy also presented this paper according to his Curriculum Vitae, which is number 50 in his publications list:

The Case of the Missing Sunspots, Bulletin of the American Astronomical Society 7, 410, 1975.

It is very clear that in 1975 Dr. Eddy was giving presentations involving his research on the Maunder Minimum. The 1975 references which Dr. Parker made in 1975 were to the work of Dr. Eddy in which he was instrumental.

The New York Times has archives that go back to 1851. The first time the term “Maunder Minimum” appears is print is 1978 in reference to Dr. Eddy’s research.

In his 1976 paper in Science, Dr. Eddy gives full attribution to the contribution of Eugene Parker:

Eddy, J.A., "The Maunder Minimum", Science 18 June 1976: Vol. 192. no. 4245, pp. 1189 – 1202.

“I am most indebted to E N Parker for calling my attention to Maunder's papers, and for personal encouragement in all the work reported here.”

Dr. Parker is still very much alive and I would suggest that those given to idle speculation be carful as to what they say.

Can anyone produce one paper published before 1976 not written by Dr. Eddy or Dr. Parker which uses the term “Maunder Minimum”? If you can’t then please have the decency to retract your allegations.

Michael Ronayne
Nutley, NJ

James Annan said...


Thanks for the links! I'm not sure why they hadn't come up in my searching. So maybe Eddy reclaims the title, if his EOS piece predates the Parker one (but this is not clear from the reference). In any case, it seems clear that the name was generally accepted prior to the 1976 paper which would agree with the recollection of my contacts.I'm not sure which "allegations" you would like to see withdrawn.