Overview
- The BiSON-led study published May 28–29 used almost 40 years of Sun-as-a-star p-mode data covering solar cycles 22–25 to compare internal signals with traditional surface measures.
- Researchers found that magnetic activity has become progressively squeezed into a layer roughly 1,000 kilometres below the photosphere, with the effect strongest in Cycle 25.
- High-frequency p-mode frequency shifts in Cycle 25 are much larger than expected from sunspot counts and radio flux, showing a clear mismatch between seismic indicators and surface proxies.
- The team grouped oscillations into low-, mid- and high-frequency bands to probe different depths and traced the divergence back to about the decline of Cycle 23, with ongoing observations planned into Cycle 26 to test persistence.
- If the change holds, scientists may need to revise solar-dynamo models and space-weather forecasts because confinement of magnetic energy near the surface could alter when and where flares and particle eruptions form, which matters for satellites, communications and power systems on Earth.