Sun’s activity to reach lowest point since last ‘mini ice age’

Chuck Bednar for – @BednarChuck

Solar activity is expected to decrease by 60 percent during the 2030s, plummeting conditions to those not seen since Earth underwent its last “mini ice age” starting in 1645, according to new research presented Thursday at the UK National Astronomy Meeting in Llandudno, north Wales.

In their study, Professor Valentina Zharkova from the Northumbria University Department of Mathematics and Information Sciences and her colleagues explained that, by using a new model of the Sun’s solar cycle, they have been able to produce “unprecedentedly accurate predictions of irregularities” within the 11-year “heartbeat” of our solar system’s central star.

Their model uses dynamo effects in two layers of the Sun, one close to the surface and one deep within its convection zone, and predicts the drastic decline in solar activity. Previously, scientists attributed the cause of the solar cycle to caused by convecting fluid deep within the Sun, but that did not explain for differences and fluctuations unique to each cycle. The addition of the second dynamo, closer to the surface, gives them a more complete and accurate picture of events.

“We found magnetic wave components appearing in pairs, originating in two different layers in the Sun’s interior,” Zharkova explained. “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.”

Dynamos to become completely out of synch by 2030

She and her colleagues developed their model using a technique known as “principal component analysis” to analyze magnetic field observations from the California’s Wilcox Solar Observatory. They studies three solar cycles worth of magnetic field activity, and found that by combining the two waves together, they could predict solar cycle activity with a 97 percent success rate.

Furthermore, they compared their predictions to average sunspot numbers, another strong marker of solar activity, and found that the observations and predictions matched closely. Based on their new model, they predict that the two waves will become increasingly offset during a cycle which peaks in 2022, and will become completely out of sync during the cycle afterwards (2030 -2040), which will result in “a significant reduction in solar activity.”

During that cycle, “the two waves exactly mirror each other – peaking at the same time but in opposite hemispheres of the Sun,” Zharkova explained. “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’.”

“Effectively, when the waves are approximately in phase, they can show strong interaction, or resonance, and we have strong solar activity,” she added. “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.”


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