The best we can determine for our own Sun's patterns has to
do with changes in its magnetic fields, which are in turn driven by complex
currents of flowing plasma deep within.
Exactly what pushes and pulls these currents in such a
rhythmic way is the part we need to figure out, but there's a temptation to link
it with a similar periodicity in planetary orbits.
"As we emerge from solar minimum and approach Cycle 25's
maximum, it is important to remember solar activity never stops; it changes form
as the pendulum swings," says NASA solar scientist Lika Guhathakurta.
While the cycle of highs and lows takes place over 11 years,
it is more accurately a reflection of a larger 22-year cycle defined by a
complete overturn in the Sun's polarity. 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 largely by outbursts of charged plasma and radiation
that can ferociously blow out into space, especially during solar maximums.
It'll be roughly another five years before we can say we're
in the thick of the Sun's more aggressive phase. That doesn't mean we needn't be
paying attention now.
Whether Solar Cycle 25 will put on a show or not is left to
be seen, though is unlikely to be explosive. Number 24 was relatively quiet,
after all, but mostly by comparison with preceding cycles which were somewhat
stronger 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 Space Weather Prediction Center in
Colorado.
"The Sun's impact on our daily lives is real and is
there."
It also pays to be realistic about what that impact is,
especially if you're not an astronaut concerned about basking in high-speed
protons and X-rays or a space engineer managing a bunch of delicate
satellites.
Down here on the surface, shielded by kilometres of
atmosphere, solar cycles are barely noticeable. If you're lucky, you might see a
slight pick-up in aurora activity during solar maximums; most of the time we
don't have to be too concerned about a solar flare destroying life as we know
it.
One thing is for sure: any relationship between 2020's rather
depressing events and the Sun's pensive mood are at best metaphorical. Still,
one can't help but wonder sometimes what the stars are thinking.
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