• Wed. Sep 23rd, 2020

Dimancherouge

Technology

A Solar Forecast With Good News for Civilization as We Know It

The sun is beginning to perk up again.

An international panel of scientists announced on Tuesday that the sun had emerged from the quietest part of its 11-year sunspot cycle and had now entered the 25th numbered cycle. (The numbering of sunspot cycles goes back to 1755.)

The researchers predicted that the forthcoming cycle would be a pretty quiet one.

Solar scientists track the cycle through the ebb and flow in the number of sunspots, which reflects the level of ferocity in the sun’s magnetic fields. Sunspots can shoot out bursts of radiation called solar flares as well as giant eruptions of particles known as coronal mass ejections. If a giant coronal mass ejection hit Earth, it could upend modern civilization, knocking out satellites and inflicting continentwide blackouts.

Such a solar explosion in 1859, known as the Carrington event, disrupted telegraph systems. Today, the world is more electrically interconnected, and giant transformers that are part of power grids are thought to be particularly vulnerable.

Just as economists wait months to declare the start or end of a recession, scientists delay such pronouncements for solar cycles, because they average the sunspot numbers over 13 months to avoid being fooled by short-term fluctuations in the sun’s activity. Nine months ago, in December, the sunspot cycle reached its calmest state.

“We’ve gotten very good at modeling the evolution of the polar magnetic fields,” Dr. Upton said. “This is one of the best indicators for the amplitude of the coming cycle and was one of the main features that the prediction panel looked at.”

She said there were other indicators that this cycle would remain quiet, including a large number of spotless days during the solar minimum. But if in the coming months the sunspot cycle ramps up faster than expected, that will be a sign that perhaps the experts underestimated the coming cycle’s intensity, she said.

Even during weaker solar cycles, the sun can unleash gigantic explosions. In 2012, an eruption rivaling the Carrington event erupted off the sun’s surface — but fortunately it was not aimed at Earth.

Still, a quieter sun increases the odds that our planet will not be struck by a solar cataclysm in the next 11 years.

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