Tag: solar maximum

The uncertainty of science: New data, when compared with similar data collected over decades, suggests the Sun’s solar cycle is undergoing some fundamental changes.

In work just published in the Monthly Notices of the Royal Astronomical Society, the team shows that the interior of the Sun has changed in recent years, and that these changes persist in the current cycle. In combination with theoretical models, the observations suggest that the magnetic field distribution in the outer layers may have become a bit thinner. Other seismic data shows that the rotation rate of the Sun has also undergone some changes in the way the Sun rotates at different latitudes.

“Again, this is not how it used to be and the rotation rate has slowed a bit at latitudes around about 60 degrees. We are not quite sure what the consequences of this will be but it’s clear that we are in unusual times. However, we are beginning to detect some features belonging to the next cycle and we can suggest that the next minimum will be in about two years,” says Elsworth.

First, they don’t know what will happen because of these changes. Second, their data confirms that the solar minimum will occur in about two years, which would make this cycle only 9 years long, one of the shortest but also one of the weakest that has been observed, two things that previously had never gone together.

Today NOAA posted its monthly update of the solar cycle, covering sunspot activity for April. It is posted below, with annotations, as I have done now every month since 2010.

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.

April showed an uptick in sunspot activity, enough to move the numbers back up above the 2007 low prediction. Nonetheless, activity as the cycle has been ramping down has consistently and generally remained below expectation, and does seem heading to an early arrival of solar minimum, sometime in late 2019 or early 2020, about a year early.

I don’t want to sound like a broken record, as I have written this practically every month since I started these updates in 2010, but this short and weak solar maximum suggests the possibility that we might be facing a grand minimum, where there are no significant sunspots for decades. Some solar scientists think this is coming. Others are much more doubtful. Regardless, we can only wait and watch, while also recognizing that weak solar maximums and grand minimums have in the past consistently coincided with global cool weather. The reasons why this has happened are not yet known, but it has happened nonetheless.

The Sun just completed its longest stretch, 15 days, without sunspots since 2009, suggesting once again that the solar minimum is coming much sooner than expected.

So far this year the Sun has been blank 34% of the time, a pace that makes this year almost as blank as 2009, the year in which the previous solar minimum ended. This suggests that 2017 might be the year in which the next solar minimum begins, which would be about two years earlier than the earliest predictions.

The more likely scenario is that 2018 will be the year the solar minimum begins, with 2019 when solar activity bottoms out. This will still be much earlier than expected, making this solar cycle only about 9-10 years long. What makes this more significant is that historically short cycles always went with high activity, while long cycles signaled an inactive and weak maximum. This cycle will be the first that is both short and weak.

What happens next remains the big question. Will the Sun enter a grand minimum, with no sunspots for decades? Or will sunspot activity continue? Since solar scientists really do not yet understand the mechanism within the sun’s magnetic field that causes this solar cycle, we really can’t answer these questions, in advance. We must wait, and see.

The monthly NOAA update of the solar cycle was released yesterday, showing the Sun’s sunspot activity in April. It is annotated and posted below.

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.

After four months of steady decline matched exactly with the low prediction from 2007 (the lower green line curve), in April sunspot activity plummeted to the lowest level seen since January 2011.

This decline shouldn’t surprise anyone. The now ending solar maximum has been the weakest in a century and, as noted here, it is now more than a year since the last X-class solar flare, the most powerful kind, with this solar maximum seeing only 45 X-class events, compared to 126 during the previous solar maximum.

As I have noted repeatedly, the big question now is what will happen during the next solar cycle. Will we get another weak solar cycle or will the sun’s sunspot activity recover? Or will sunspots vanish and will the sun enter a grand minimum, with no sunspots for decades? At the moment no one knows, though some solar scientists favor the latter.