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Our sun has officially hit its solar maximum, with increased rates of auroras and solar flares expected in the coming months, NASA has announced.
The sun goes through 11-year cycles of activity, fluctuating between its solar minimum and solar maximum, where it has a large number of sunspots and is more prone to powerful solar flares and coronal mass ejections.
We are currently in Solar Cycle 25, which began in December 2019, and are now in the grips of this cycle’s solar maximum—and could potentially stay in this phase for another year or so.
“Currently, we’re about two years into the maximum period, so we’re anticipating another year or so of maximum phase before we really enter the declining phase, which will lead us back to solar minimum,” Lisa Upton, co-chair of the Solar Cycle Prediction Panel and lead scientist at Southwest Research Institute in San Antonio, Texas, said at a NASA press conference announcing the maximum on October 15.
The solar cycle is driven by changes in the sun’s magnetic field, as at the solar maximum, its magnetic field flips, with the north and south magnetic poles switching places.
“During solar maximum, the number of sunspots, and therefore, the amount of solar activity, increases,” Jamie Favors, director of the Space Weather Program at NASA Headquarters in Washington D.C., said in a statement.
“This increase in activity provides an exciting opportunity to learn about our closest star—but also causes real effects at Earth and throughout our solar system.”
These solar flares and coronal mass ejections can result in radio blackouts and geomagnetic storms in the Earth’s atmosphere, potentially leading to issues with the power grid, satellite problems, and the aurora being seen further away from the poles than usual.
“During a solar storm, explosions on the solar surface, called coronal mass ejections (CMEs), emit high-speed charged particles that in some cases arrive at Earth and interact with molecules in the ionosphere,” Roger Dube, a professor of physics at the Rochester Institute of Technology in New York, told Newsweek.
“A G4 solar storm, for example, will likely cause RF [radio frequency] noise and minor problems with the power grid, telecommunications, and GPS. There are about 100 G4 solar storms per solar cycle.”
A G4 storm hit the Earth this past week, caused by a CME released from sunspot AR3848 at the same time as a powerful X1.8-flare on October 8. Geomagnetic storms are measured on a scale of G1 to G5, with G5 being the most powerful and least commonly seen.
At its solar maximum, the sun is more prone to increasingly powerful flares and CMES. An X9.0 flare released on October 3 was the most powerful flare of the cycle thus far, and the G5 geomagnetic storm that occurred on May 10 this year was the first G5 seen since 2003.
We may still see increased levels of activity in the coming year, and we still may not have reached the absolute peak of the solar cycle. We won’t truly know when the maximum occurred until solar activity starts to decrease again.
“This announcement doesn’t mean that this is the peak of solar activity we’ll see this solar cycle,” Elsayed Talaat, director of space weather operations at the National Oceanic and Atmospheric Administration said in the statement.
“While the sun has reached the solar maximum period, the month that solar activity peaks on the sun will not be identified for months or years.”
This cycle has been more active than scientists first predicted, as Solar Cycle 24 was fairly quiet even during its maximum.
“Solar Cycle 25 sunspot activity has slightly exceeded expectations,” Upton said. “However, despite seeing a few large storms, they aren’t larger than what we might expect during the maximum phase of the cycle.”
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