Sun Rumblings Herald New Phase For Our Star

Despite only being halfway through our current solar cycle, the sun is showing signs of starting another.

The sun is approaching the solar maximum of its current 11-year solar cycle, meaning that it will peak in activity soon before becoming less and less active towards its solar minimum and the end of the current cycle.

However, the sun might be showing signs of kicking off its next cycle already, researchers from the University of Birmingham recently revealed at the Royal Astronomical Society's National Astronomy Meeting in the United Kingdom.

The solar cycle is driven primarily by the complex dynamics of the sun's magnetic field. This magnetic field is generated by the solar dynamo process, which is driven by the movement of plasma within the sun. During each cycle, the sun's magnetic field undergoes a complete reversal, meaning the magnetic north and south poles switch places, which occurs around the solar maximum.

At solar minimum, there are few sunspots and minimal solar activity, as the magnetic field is stable and simple, usually with a dipole structure. Approaching the solar maximum—which we are currently doing—sunspot numbers increase as the solar magnetic field becomes more complex and twisted, resulting in more frequent solar flares and coronal mass ejections. Our next solar maximum is forecast to occur between late 2024 and early 2026.

"The sun has an approximately 11-year sunspot (or solar) cycle. We are now into Solar Cycle 25, which began in December of 2019. As we approach the peak activity about halfway through, sunspots become more active and emit solar flares. These flares occur when the magnetic fields on the sun become twisted," Roger Dube, a professor of physics at the Rochester Institute of Technology, told Newsweek.

"The magnetic fields can break, causing solar flares that are electromagnetic storms on the surface of the sun. These are huge by Earth standards, about the size of a planet, and the electromagnetic effects can be intense even as far as Earth. Sometimes, these flares cause a massive amount of solar plasma to be emitted into space in the form of a Coronal Mass Ejection, or CME."

However, preliminary studies by researchers at the University of Birmingham have detected signs that the sun might be starting its next cycle already. These results have not yet been published in a peer-reviewed journal.

Astronomers measure the sun's rotation using its internal sound waves, which allows them to study rotating belts of plasma within the star (solar torsional oscillation). Previous data shows that these belts tend to speed up a few years before a solar cycle begins.

"If you go back one solar cycle - 11 years - on the plot, you can see something similar that seems to join up with the shape that we saw in 2017. It went on to be a feature of the present solar cycle, Cycle 25," Rachel Howe, a research fellow at the University of Birmingham, said in a statement. "We're likely seeing the first traces of Cycle 26, which won't officially start until about 2030."

Solar torsional oscillation signals on the sun currently look the same as they did before previous solar cycles began.

"It's exciting to see the first hint that the pattern will repeat again in Cycle 26, which is due to start in about six years," Howe said. "With more data, I hope we can understand more about the part these flows play in the intricate dance of plasma and magnetic fields that form the solar cycle."

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