Scientists: The solar cycle was only 8 years long during the Maunder Minimum in the 1600s

Using archival records gathered in Korea during the 1600s when the Sun was undergoing a long period of almost no sunspots — called the Maunder Minimum — scientists have discovered evidence that the solar cycle during that time was only 8 years long.

You can read their paper here. Since almost no sunspots were visible at that time, the scientists used reports of aurora in Korea to determine periods when the Sun was more active. From their abstract:

By analyzing the variations in solar activity-related equatorial auroras recorded in Korean historical books in the vicinity of a low-intensity paleo-West Pacific geomagnetic anomaly, we find clear evidence of an 8-year solar cycle rather than the normal 11-year cycle during the Maunder Minimum.

This 8-year cycle is shorter than the 9-year cycle that other researchers had estimated based on the few sunspots that did appear during this grand minimum. Both conclusions however challenge what is known of the Sun. Since the 11-year cycle resumed in the 1700s, short cycles have generally been associated with very active periods, the opposite of what has been found during Maunder.

In other words, we know better what happened, but have no understanding of why. Since the Maunder Minimum appears associated with the Little Ice Age of the 1600s, and fits other data that says the climate cools when the Sun produces few sunspots, gaining some understanding of this process is important for understanding past and future changes to the global climate.

Astronomers discover a solar twin whose sunspot cycle changed into a grand minimum

Astronomers studying the sunspot cycle of several dozen stars that are twins of our Sun have identified for the first time a star whose 17-year cycle suddenly ceased, going into an extended grand minimum.

Comparing these stars to the Sun enables astronomers to better determine how typical – or not – the Sun is as a star. The Sun’s magnetic activity is defined by its 11-year sunspot cycle. Of the 59 stars that Baum’s team surveyed, 29 appeared to also have starspot cycles, and the period of those cycles could be measured for 14 of them.

“Of these 14 stars, the average length of their cycle is just under 10 years, which is similar to the Sun’s 11-year cycle,” Baum tells Physics World. However, not all the stars adhered to this time frame. One star that was surveyed has a cycle lasting less than four years, while another star, HD 166620, had a cycle 17 years long.

Note the past tense. Sometime between 1995 and 2004, HD 166620’s starspot cycle simply stopped.

When or if the star’s sunspot activity resume is unknown. The Sun’s last grand minimum, dubbed the Maunder Minimum, lasted 70 years during the 1600s.

No one yet understands why stars do this. This discovery however now shows that the Sun is not unique in this behavior.

Sunspot update March 2019: An upcoming Grand Minimum?

Even though we are now deep into the beginning of what might become the first grand minimum in sunspot activity since the invention of the telescope, that does not mean the Sun has as yet stopped producing sunspots. Yesterday NOAA released its the monthly update of its tracking of the solar cycle, adding sunspot activity for March 2019 to its graph. Below is that graph, annotated by me to give it some context.

It shows the Sun with a slight burst in activity in March, suggesting that though we are now in the solar minimum that minimum still has the ability to produce sunspots.

At the same time, for me to say that we might be heading to a grand minimum, a time period lasting many decades where no sunspots are visible and the sunspot cycle essentially ceases, is not click bait or hyperbole. It is instead based on what I now think the solar science community is thinking, based on this very graph.

March 2019 sunspot activity

The graph above has been modified to show the predictions of the solar science community for the previous solar maximum. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction, extended in November 2018 four years into the future.

For past half dozen or so cycles the solar science community had issued its prediction for the upcoming solar maximum at about this stage in the overall cycle, during the final ramp down to minimum when it was clear that the Sun had entered that minimum.

This cycle’s prediction however has not yet happened, and in fact appears to be late. In fact, the extension of the May 2009 red curve that was made in November 2018 might very well be the only prediction we see. That extension is shown by the differences between the green 2007 prediction and the red 2009 prediction in the graph. Before November 2018 both curves ended at the same place, the end of 2018.

The extension of that red curve is important. As I noted in my December 2018 sunspot update,
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Sunspot update for July 2018: The Sun flatlines!

Yesterday NOAA posted its monthly update of the solar cycle, covering sunspot activity for July 2018. As I do every month, I am posting it below, annotated to give it some context.

This might be the most significant month of solar activity that has been observed since Galileo. Except for two very short-lived and very weak sunspots that observers hardly noted, the Sun was blank for entire month of July. This has not happened since 2009, during the height of the last solar minimum.

What makes this so significant and unique is that it almost certainly signals the return of the next solar minimum, a return that comes more than a year early. The solar cycle the Sun is now completing has only been ten years long. It is also one of the weakest in more than a hundred years. This combination is unprecedented. In the past such a weak cycle required a long cycle, not a short one.
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The first sunspots of the next solar cycle

In linking to my sunspot update this week, there has been a lot of speculation at the climate website WattsUpWithThat that the next solar cycle has begun.

Our resident solar physicist, Dr. Leif Svalgaard commented and provided a link to something reported by his colleagues, something that likely would not have been possible without the fantastic solar observations of NASA’s Solar Dynamic Observeratory (SDO). He said: “Cycle 25 has already begun. It looks to me that SC25 will be a bit stronger than SC24, so probably no Grand Minimum this time.” It seems a small sunspot has been observed, that has the opposite polarity of cycle 24 sunspots. [emphasis in original]

The speculation at WattsUpWithThat, which suggested that this sunspot was the first such sunspot this cycle, was not quite accurate however. This sunspot with an opposite polarity, which decayed so quickly that it did not rate getting a sunspot number, was not the first. This week the Solar-Terrestrial Centre of Excellence, a Belgian organization focused on space-solar science, published this very good article discussing not only this sunspot but two others, one of which occurred more than a year ago.
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Decline to solar minimum continues

It’s that time again buckos! On Monday NOAA posted its monthly update of the solar cycle, showing the Sun’s sunspot activity in October. As I have done every month since 2010, I am posting it here, with annotations to give it context.

The decline in sunspot continue steadily, matching the red prediction curve except that, as it has for this entire solar maximum, the number of sunspots continues to be less than expected. Not only did the ramp up start later and not quite reach the levels predicted, the ramp down started early. Overall, this now ending solar maximum is the weakest in a century. The big question remains: Is the Sun about to head into its first Grand Minimum since the 1600s, or is this weak maximum a one-time event to be followed by stronger activity in later cycles.

No matter what anyone tells you, no one knows.

October 2015 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

A new double dynamo theory to explain the Sun’s solar cycle

A team of solar scientists have proposed a new theory that they think explains the ebb and flow of the Sun’s eleven year solar cycle, and if right can explain the periodic occurrence of grand minimums where there are essentially no sunspots for decades, such as the Maunder Minimum in the 1600s.

The theory proposes that the Sun has two different dynamos that produce different magnetic waves in its interior. Like waves that can either cancel each other out or combine for more power, these two dynamos do the same over time and thus effect the Sun’s sunspot/solar cycle.

“We found magnetic wave components appearing in pairs, originating in two different layers in the Sun’s interior. They both have a frequency of approximately 11 years, although this frequency is slightly different, and they are offset in time. Over the cycle, the waves fluctuate between the northern and southern hemispheres of the Sun. Combining both waves together and comparing to real data for the current solar cycle, we found that our predictions showed an accuracy of 97%,” said Zharkova.

Zharkova and her colleagues derived their model using a technique called ‘principal component analysis’ of the magnetic field observations from the Wilcox Solar Observatory in California. They examined three solar cycles-worth of magnetic field activity, covering the period from 1976-2008. In addition, they compared their predictions to average sunspot numbers, another strong marker of solar activity. All the predictions and observations were closely matched.

Looking ahead to the next solar cycles, the model predicts that the pair of waves become increasingly offset during Cycle 25, which peaks in 2022. During Cycle 26, which covers the decade from 2030-2040, the two waves will become exactly out of synch and this will cause a significant reduction in solar activity.

“In cycle 26, the two waves exactly mirror each other – peaking at the same time but in opposite hemispheres of the Sun. Their interaction will be disruptive, or they will nearly cancel each other. We predict that this will lead to the properties of a ‘Maunder minimum’,” said Zharkova. “Effectively, when the waves are approximately in phase, they can show strong interaction, or resonance, and we have strong solar activity. When they are out of phase, we have solar minimums. When there is full phase separation, we have the conditions last seen during the Maunder minimum, 370 years ago.”

And on this same subject, last week NOAA posted its monthly update of the solar cycle, showing the Sun’s sunspot activity in June. As I have done every month since 2010, I am posting it here, below the fold, with annotations to give it context.
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We don’t need no solar maximum

It is that time again! Today, March 4, NOAA released its monthly update of the Sun’s sunspot cycle, covering the period of February 2013. As I do every month, I am posting this latest graph, with annotations to give it context, below the fold.

Once again, the Sun has shown a complete inability to produce sunspots, at the very moment it had been predicted to be rising towards its maximum in the sunspot cycle. The numbers in February plunged from the tepid rise we saw in January to below the crash we saw in December. Right now, when the Sun is supposed to peaking, it is instead producing sunspots in numbers as low as seen in 2011, at the very end of the last solar minimum.
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The Sun continues to fizzle

Yesterday NOAA posted its monthly update of the ongoing sunspot cycle of the Sun. You can see this latest graph, covering the month of July, below the fold.

As we have seen now for almost four years, the Sun continues to under-perform the predictions of solar scientists when it comes to the number of sunspots it is producing. In fact, that the sunspot number did not rise in July is surprising, as July had appeared to be a very active month for sunspots, with some of the strongest solar flares and coronal mass ejections seen in years. Instead, the number declined ever so slightly.
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In a paper published today in Geophysical Research Letters, researchers studying an icecore drilled in the West Antarctic Ice Sheet have found strong evidence of the 16th century Little Ice Age in the southern hemisphere.

In a paper published today in Geophysical Research Letters, researchers studying an ice core drilled in the West Antarctic Ice Sheet have found strong evidence of the 16th century’s Little Ice Age in the southern hemisphere. From the abstract:

The temperature in the time period 1400–1800 C.E. was on average 0.52 ± 0.28°C colder than the last 100-year average. … This result is consistent with the idea that the [Little Ice Age] was a global event, probably caused by a change in solar and volcanic forcing, and was not simply a seesaw-type redistribution of heat between the hemispheres as would be predicted by some ocean-circulation hypotheses.

In an effort to emphasis human-caused global warming and eliminate any evidence of climate change caused by other factors, many global warming scientists have argued that the Little Ice Age was not a global event but merely a cooling in Europe. This data proves them wrong. The global climate has varied significantly in the recent past, and not because of human behavior. Other factors, such as fluctuations in the solar cycle, must be considered more seriously for scientists to obtain a better understanding of the Earth’s climate.

The link between sunspots and climate

In a preprint paper published today on the Los Alamos astro-ph website and accepted for publication in the Journal of Atmospheric and Solar-Terrestrial Physics, Norwegian scientists have found a strong correlation between the length of the solar sunspot cycle and the Earth’s temperature during the following cycle. From the abstract:

Relations between the length of a sunspot cycle and the average temperature in the same and the next cycle are calculated for a number of meteorological stations in Norway and in the North Atlantic region. No significant trend is found between the length of a cycle and the average temperature in the same cycle, but a significant negative trend is found between the length of a cycle and the temperature in the next cycle. This provides a tool to predict an average temperature decrease of at least 1.0 ◦ C from solar cycle 23 to 24 for the stations and areas analyzed. We find for the Norwegian local stations investigated that 25–56% of the temperature increase the last 150 years may be attributed to the Sun. For 3 North Atlantic stations we get 63–72% solar contribution. [emphasis mine]

You can download a copy of the paper here [pdf].

Their paper finds that if a particular sunspot cycle is longer with less activity, the climate will show significant cooling during the next cycle.

The paper makes several important points:
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Two climate papers of interest

When I appear on radio and am talking about climate change, I often get the same questions over and over.

  • Is the climate warming?
  • If so, is human behavior an important factor for causing that warming?
  • How much does the sun influence climate change?
  • Is the ozone hole linked to climate change?

The truth is that, right now, no one can really answer any of these questions with any certainty. While a large majority of climate scientists might be convinced the Earth is warming and that human activity is causing this warming, the public has great doubts about these claims, partly because of the untrustworthy behavior of many of these climate scientists and partly because the science itself is often confusing.

We simply don’t yet have enough data. Worse, much of the data we do have is tainted, unreliable because of the misconduct and political activism of the very climate scientists who are trying to prove the case for man-made global warming.

Two new papers, published today in Geophysical Research Letters, add some interesting but small data points to this whole subject.
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A fired up Sun

As it does every month, NOAA’s Space Weather Prediction Center today released its monthly update showing the ongoing changes of the Sun’s solar cycle sunspot activity. I have posted the graph below the fold.

For the fourth month in a row the Sun’s sunspot activity has leaped upward. In fact, for the first time since I have been tracking sunspot activity, beginning in 2008, the Sun’s sunspot activity exceeds the predicted activity by a significant amount. Since the end of the previous maximum, the Sun had consistently failed to meet the expectations of solar scientists by producing far fewer sunspots than expected.

In the past few months, however, the Sun has recovered, its activity firing upward, including some of the most active and largest sunspots in years.
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The wimpy maximum continues

The monthly updated graph of the Sun’s solar cycle sunspot activity was released today by NOAA’s Space Weather Prediction Center. I have posted the June graph below.

For the third month in a row, there was a decline in sunspot activity. Though the sun is producing sunspots quite regularly and there hasn’t been a blank day since January 16, the numbers of sunspots continue to fall far below the predicted level of activity as indicated by the red line.

All this is no longer a surprise or unexpected. As the solar science community noted last month, they have now gathered enough data to convince them that the sun appears to be going quiet, and might even follow this very weak solar maximum — the weakest possibly in 200 years — with a decades-long period of no sunspots at all.

This graph, however, is very intriguing. Even with an expected weak solar minimum, the sun should be producing more sunspots each month, not less, as shown on the graph. This suggests that the most up-to-date predictions for the next solar maximum might still be too high.

The sunspot graph for June 2011

Solar scientists predict a major decline in sunspot activity

At a press conference today at the 2011 meeting of the Solar Physics Division (SPD) of the American Astronomical Society (AAS) in Las Cruces, New Mexico, solar scientists predicted that not only will the next solar maximum in 2013 be the weakest in centuries, it is very likely that it will be followed by another long Maunder Minimum, a period of decades without sunspots. “The sun may be going into hiatus,” says Dr. Frank Hill, associate director of the NSO’s Solar Synoptic Network. You can read the press releases for this announcement here and here.

decline in magnetic field over the last few cycles

These conclusions are based on three lines of evidence:

  • There has been a long term weakening in the magnetic strength that produces sunspots themselves. The declining trend suggests that by 2022 it will no longer be strong enough to produce sunspots. The graph above shows this decline.
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