Early signs of Solar Cycle 26 detected nidway through Cycle 25

Early signs of Solar Cycle 26 detected nidway through Cycle 25
by Sophie Jenkins
London, UK (SPX) Jul 19, 2024

Researchers have detected early signs of the Sun's next 11-year solar cycle, despite being only halfway through the current one. This discovery was made through the observation of sound waves within the Sun.

Currently at its peak or 'solar maximum,' Cycle 25 has seen the Sun's magnetic field flip, causing an increase in sunspots, flares, and coronal mass ejections. These activities result in heightened electromagnetic energy impacting Earth and more frequent auroras visible at lower altitudes.

Cycle 25, which began in 2019, is projected to continue for another six years. However, researchers from the University of Birmingham have identified the first signs of the next solar cycle. These findings were presented at the Royal Astronomical Society's National Astronomy Meeting in Hull.

By using the Sun's internal sound waves, astronomers measure its rotation and observe patterns of bands (solar torsional oscillation) that rotate at varying speeds. These bands move towards the Sun's equator and poles during the activity cycle, with faster-rotation belts typically appearing before a new cycle begins.

Dr. Rachel Howe and her international team detected faint indications of the next solar cycle in their analysis of the rotation bands data. "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," said Dr. Howe. "We're likely seeing the first traces of Cycle 26, which won't officially start until about 2030."

Since 1995, helioseismic data from the Global Oscillation Network Group (GONG), the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory, and the Helioseismic and Magnetic Imager (HMI) on the Solar Dynamics Observatory have been used to study solar torsional oscillation signals. This data now includes the first four years of Solar Cycles 23, 24, and 25, enabling researchers to compare the rising phases of these cycles.

Dr. Howe has tracked the Sun's rotational changes for about 25 years, beginning with data from Solar Cycle 23 from GONG and MDI. She observed the pattern of faster-moving material drifting towards the equator along with the sunspots. This pattern has been observed, albeit not exactly, in Cycle 24 and now in Cycle 25.

"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. 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," she said.