SESK: Stuff Everyone Should Know · sesk.info/astro-sunspot-cycle-11-years
On average, how many years pass between sunspot maximums?
About 11 years, though cycles have run from 9 to 14 years.
- About 1 year
- About 11 years ✔
- About 76 years
Why: Sunspot numbers rise and fall in a cycle averaging 11 years. It was found by Heinrich Schwabe, an amateur who counted sunspots daily from 1826 to 1850 while hunting for a planet inside Mercury's orbit.
Huh, didn't know that: Even at sunspot maximum, less than half of one percent of the Sun's surface is covered by spots.
The Sun's 11-year cycle is patient. It always takes time to spot a trend.
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References
Answer: About 11 years. Sunspot numbers rise and fall in a cycle averaging 11 years. It was found by Heinrich Schwabe, an amateur who counted sunspots daily from 1826 to 1850 while hunting for a planet inside Mercury's orbit.
- Astronomy 2e, 15.2 The Solar Cycle openstax.org/books/astronomy-2e/pages/15-2-the-solar-cycle
We now know that sunspot maxima occur at an average interval of 11 years
Checked 2026-10-10.
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