Scientists have developed a forecasting technique that could reveal the strength of the Sun's next activity cycle as many as seven years before it reaches its maximum.

The method focuses on the number of sunspots present at a newly identified "switch-off" stage in the solar cycle. At this point, the Sun's most severe space weather appears to end abruptly. Researchers have already used the approach to produce an early estimate for Solar Cycle 26.

Initial projections suggest that Cycle 26 could be moderate, with a sunspot number of roughly 100 to 120. That would make it comparable to, or possibly weaker than, the current Solar Cycle 25. However, researchers will not be able to make a more precise forecast for about two years, and both stronger and weaker outcomes remain theoretically possible.

The findings are being presented this week at the Royal Astronomical Society's National Astronomy Meeting in Birmingham.

The Sun's Extreme Weather Stops Suddenly