Our Sun Has Entered a New Cycle, And It Could Be One of The Strongest Ever Recorded

You are likely aware that the earth has two poles: the North Pole and the South Pole. Once in about every 780 thousand years, the poles flip. The sun also has two poles, but these poles switch much more frequently- every eleven years. This is called the solar cycle, or sun cycle.

The activity level of the sun throughout these cycles is highly variable. The sun has now entered a new cycle, and some scientists are predicting it could be one of the strongest they have ever seen.

Sun Cycles: Definitions

Before we jump into solar cycles and why this new one is going to be so strong, let’s define a few terms:

The magnetic field: The sun’s plasma consists of two things: positively charged ions and negatively charged electrons. Because the sun is so hot, the plasma creates many complicated magnetic fields that twist and turn. This is called solar activity [1].

Sunspots: these are areas that appear dark on the surface of the sun. They look darker because they are cooler than other areas of the sun. They form in areas where the sun’s magnetic field is particularly strong- so strong that they keep some of the heat within the sun from reaching its surface [2].

Solar Flares: The lines of the magnetic field near a sunspot often tangle, cross, and reorganize. When this happens, it can cause a sudden explosion of energy, called a solar flare. These flares release a lot of radiation into space, and can even interfere with radio communications on earth if they are particularly strong [2].

Coronal Mass Ejections (CMEs): these are large expulsions of plasma and particles from the sun. They sometimes accompany solar flares, and travel outward from the sun at extraordinarily high speeds. The fastest CMEs that travel in our direction can reach earth in as little as fifteen to eighteen hours [3].

Solar maximum: when the sun’s magnetic field is at its strongest.

Solar minimum: this is when the sun’s magnetic field is at its weakest [4].

The Strongest Solar Cycle Ever Recorded

According to new predictions, the sun is approaching the next maximum in its solar cycle, and this one could be one of the strongest we’ve ever seen. 

Scott McIntosh is a solar physicist with the National Center for Atmospheric Research. He says that scientists lack a fundamental understanding of the mechanism that drives solar cycles. This makes it difficult for them to predict both their length and strength.

“If our forecast proves correct,” he explained, “we will have evidence that our framework for understanding the Sun’s internal magnetic machine is on the right path.” [5]

This is important, because he and his team’s predictions are in direct contradiction to the official solar weather forecast from NASA and the NOAA.

There is a lot we do not know about the upcoming sun cycle, but there is one certainty: Every eleven years, the north pole becomes the south pole, and the south becomes the north. When this reversal happens, the sun’s magnetic field is at its weakest. We call this sun cycle the solar minimum because during this time, there is very little activity on the sun’s surface. In other words, there are far fewer sunspots, solar flares, and CMEs.

Once the poles switch, however, the magnetic field strengthens. When this happens, activity on the sun’s surface increases to a solar maximum. It will later decrease as a new pole switch approaches.

Contradicting Opinions

The most recent solar minimum occurred between solar cycle 24 and 25, in December 2019. That means that now, we are in solar cycle 25 and are headed toward a solar maximum. Doug Biesecker, Ph.D., is a panel co-chair and a solar physicist at NOAA’s Space Weather Prediction Center. He says that how quickly solar activity rises is an indicator of how strong the solar cycle will be.

“Although we’ve seen a steady increase in sunspot activity this year, it is slow,” he explained [6].

For this reason, NASA and the NOAA believe that solar cycle 25 will be relatively quiet. 

Terminator Events

Why then, are McIntosh and his team predicting the opposite?

Back in 2014, they published a paper that described a 22-year solar cycle. Scientists have, for a long time, considered this to be a full cycle because this is when the poles return to their original positions. 

In their research, McIntosh and his team noticed that over the course of about twenty years, flickers of extreme ultraviolet light appeared to move from the poles to the equator. As they did this, these coronal bright points would meet in the middle. 

Their movement across mid-latitudes seemed to coincide with sunspots, and McIntosh believes they are linked with the magnetic fields that wrap around the sun.

These bright points, he said, have opposite polarity. For this reason, when they meet in the middle they cancel each other out. The researchers call these “terminator events”, and say that they mark the end of one solar magnetic cycle and the beginning of the next [7].

The speed at which these bands travel, however, is variable. This means that the length of time between terminator events will also vary. What the team noticed is that there was a connection between the amount of time between terminators and the intensity of the subsequent solar maximum.

The researchers found that a longer time between terminators caused a weaker solar maximum. By contrast, shorter solar cycles that are less than eleven years seem to cause much stronger solar maxima. 

For example, the longest cycle on record was solar cycle 4, which lasted fifteen years. The following maximum had only 81 sunspots. Shorter cycles, by contrast, result in maxima that have over two hundred sunspots [5].

Solar Cycle 25

According to the researchers, solar cycle 24 was less than ten years long. If their predictions are correct, there should be a large number of sunspots by the mid-2020s.

“Once you identify the terminators in the historical records, the pattern becomes obvious,” said McIntosh. “A weak Sunspot Cycle 25, as the community is predicting, would be a complete departure from everything that the data has shown us up to this point.” [5]

So who’s prediction is correct? NASA and the NOAA’s, or McIntosh and his team? For now, we just have to wait and see what happens. By the middle of this decade, however, the sun will give us all the answers we’re looking for.

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References

1. ” How does the Sun’s magnetic field work?” IBEX.
2. “Sunspots and Solar Flares.” Space Place.
3. “CORONAL MASS EJECTIONS.” SWPC.
4. “Our Sun Has Entered a New Cycle, And It Could Be One of The Strongest Ever Recorded.” Science Alert. Michelle Starr. December 8, 2020.
5. “NEW SUNSPOT CYCLE COULD BE ONE OF THE STRONGEST ON RECORD.” NCAR.UCAR. Laura Snider. December 7, 2020.
6. “Hello Solar Cycle 25.” NWS.
7. “DECIPHERING SOLAR MAGNETIC ACTIVITY. I. ON THE RELATIONSHIP BETWEEN THE SUNSPOT CYCLE AND THE EVOLUTION OF SMALL MAGNETIC FEATURES.” IOP Science. Scott W. McIntosh Et al. August 8, 2014.