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Far from the evils of planet Earth, our Sun has had a fairly quiet year. A close look at its activity confirms what solar energy enthusiasts have been suspecting for a while: our closest star has entered a new cycle.
Since we began seriously tracking the sun’s dark spots, humans have noticed a pattern of inactivity and temperament that repeats about every 11 years.
There have been 24 of these cycles since the observations were first recorded in the mid-18s.th century. And, according to a panel made up of experts from NASA and the National Oceanic and Atmospheric Administration (NOAA), December 2019 marked the beginning of number 25.
You cannot blame him for not realizing the change. There were no flashes of light, no cosmic trumpets. Just an appearance of low-temperature shadows called sunspots at high latitudes.
“We keep a detailed record of the few tiny sunspots that mark the beginning and emergence of the new cycle,” says Frédéric Clette, director of the Global Sunspot Index at the Center for Long-Term Solar Observations and Data.
“These are the tiny heralds of the giant solar fireworks of the future. It is only by following the general trend over many months that we can determine the turning point between two cycles.”
In practice, variations in the behavior of the Sun make it impossible to identify a new beginning until it has passed. It was necessary to examine data on solar activity for the last eight months to confirm that last year was as boring as the Sun in the next decade.
Despite centuries of careful recording of these 11-year cycles, we still do not have the mechanisms behind these cycles fully resolved. Periodicity in stars is quite common; Looking out into the Universe, there are a variety of pulsating objects that seem to flash and darken at intervals that you could almost set your clock.
The best we can determine for our own Sun’s patterns has to do with changes in its magnetic fields, which in turn are driven by complex currents of plasma flowing deep within it.
Exactly what pushes and pulls these currents in such a rhythmic way is the part we have to figure out, but there is a temptation to link it with a similar periodicity in planetary orbits.
“As we move out of solar minimum and approach the maximum of cycle 25, it is important to remember that solar activity never stops; it changes shape when the pendulum swings,” says NASA solar scientist Lika Guhathakurta.
While the cycle of maxima and minima takes place over 11 years, it is more accurately a reflection of a larger 22-year cycle defined by a complete reversal in the polarity of the Sun. Every 11 years, the poles swap, returning to place at the end of the next loop.
Monitoring these transitions can help us better predict space weather, which is dictated in large part by explosions of charged plasma and radiation that can erupt fiercely in space, especially during solar maximums.
It will be about another five years before we can say that we are in the middle of the most aggressive phase of the Sun. That does not mean that we do not have to pay attention now.
Whether or not Solar Cycle 25 will put on a show remains to be seen, although it is unlikely to be explosive. Number 24 was relatively quiet, after all, but mostly compared to previous cycles that were somewhat louder than usual.
“Just because it’s a below-average solar cycle doesn’t mean there is no risk of extreme space weather,” says Doug Biesecker, co-chair of the panel and solar physicist at NOAA’s Center for Space Weather Prediction in Colorado.
“The impact of the sun in our daily life is real and it is there.”
It’s also worth being realistic about what that impact is, especially if you’re not an astronaut concerned with enjoying protons and high-speed X-rays or a space engineer who manages a bunch of delicate satellites.
Here, on the surface, protected by miles of atmosphere, solar cycles are hardly noticeable. If you are lucky, you may see a slight increase in auroral activity during solar maximums; Most of the time we don’t have to worry too much about a solar flare that destroys life as we know it.
One thing is for sure: Any relationship between the rather depressing events of 2020 and the Sun’s pensive mood is metaphorical at best. Still, one cannot help wondering sometimes what the stars are thinking.
