(ORDO NEWS) — Earth weather forecasts are more accurate than ever; trying to predict the behavior of our wild and erratic Sun is a little more difficult.
Here’s an example: according to official forecasts, the current solar activity cycle should be mild. But the gap between predictions and what is actually happening is quite significant – and it is getting wider.
The number of sunspots used as an indicator of solar activity far exceeds the predicted values calculated by NOAA, NASA and the International Space Ecology Service.
In fact, sunspot numbers have consistently exceeded predicted levels since September 2020. This could mean that, contrary to forecasts, the Sun is in the midst of an unusually strong activity cycle.
The Sun is a strange and dynamic place, and far from always active, with 11-year activity cycles that are tied to its magnetic field. These cycles have a pronounced peak and trough, known as solar maximum and solar minimum, which scientists calculate from the number of sunspots.
This is because the Sun’s magnetic field controls its activity. Sunspots are temporary regions with a strong magnetic field, and solar flares and coronal mass ejections occur when magnetic field lines break and reconnect, often at sunspot locations.
A solar minimum, when the Sun’s magnetic field is at its weakest and characterized by minimal sunspot activity, occurs when the Sun’s magnetic poles are reversed.
The last solar minimum was observed in December 2019. We are currently in the 25th solar cycle and moving towards solar maximum, which is scheduled for July 2025 – the period when sunspot activity reaches its maximum.
Solar cycle 24 was fairly quiet for solar cycles, peaking at 114 sunspots; the average is 179. The Solar Cycle Prediction Team has predicted that the 25th cycle since records began will be just as calm, with a peak of 115 sunspots.
On the contrary, the number of sunspots over the past 18 months has consistently exceeded forecasts. At the time of writing, there are 61 sunspots on the Sun, and solar maximum is still over three years away.
However, if a stronger solar cycle is in store for us, that could mean something really interesting. In 2014, a team of scientists led by solar physicist Scott McIntosh of the US National Center for Atmospheric Research studied long-term trends in solar cycles and found that 11 years is just an average. Some solar cycles are slightly longer than 11 years and some are slightly shorter.
They noticed that the solar cycle following a longer cycle is likely to be weaker. But the cycle following the shorter cycle is likely to be stronger. Solar cycle 23 was long, in line with the weakness of solar cycle 24. But solar cycle 24 was also short, just under 10 years long.
This, according to McIntosh and colleagues’ forecasts in 2020, means that the 25th solar cycle will be stronger – perhaps one of the strongest in history. And the growing number of sunspots suggests that they may have guessed something.
“Scientists have a hard time predicting the length and strength of sunspot cycles because we don’t have a fundamental understanding of the mechanism that drives the cycle,” McIntosh said at the time.
“If our prediction turns out to be correct, we will have proof that our system for understanding the Sun’s internal magnetic machine is on the right track.”
In turn, this means that we can expect very impressive solar storms following flares and coronal mass ejections on the Sun.
When solar particles launched into interplanetary space collide with Earth’s magnetic field and atmosphere, they can cause communications blackouts, power grid fluctuations and spectacular aurora. The Aurora drivers are already hard at work.
We may not get confirmation until Solar Maximum, but we look forward to learning more about our fabulous home star. And damn, it’s so interesting to watch the solar cycle.
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