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Solar & space-weather phenomenon · Solar source

The Solar Cycle

The roughly eleven-year rise and fall of the Sun's activity, traced by the number of sunspots from solar minimum to solar maximum and back. Its underlying magnetic cycle takes about twenty-two years, as the Sun's polarity flips and returns. Activity — flares, CMEs, and storms — peaks near solar maximum.

Highlights

  • The ~11-year heartbeat of solar activity

Across space weather

Knowledge connections

Sources

The primary and reference sources this topic draws on.

  • NOAA SWPCNOAA Space Weather Prediction Center

    Space-weather forecasts and alerts: aurora (OVATION), the Kp index, and the G1–G5 geomagnetic storm scale.