sunspot cycle

noun

Astronomy.

1. the cycle, averaging in duration slightly more than 11 years, in which the frequency of sunspots varies from a maximum to a minimum and back to a maximum again.

Example Sentences

Their work indicates that the maximum intensity of solar cycle 25, the ongoing sunspot cycle, is imminent and likely to occur within a year.

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In 1935, Swiss astronomer Max Waldmeier discovered that the faster the rate of rise of a sunspot cycle the stronger its strength, so stronger cycles take less time to rise to their peak intensity.

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This relationship has often been utilised to forecast the strength of a sunspot cycle based on observations of its early rising phase.

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The 11-year sunspot cycle, they say, based on an analysis of 140 years of solar measurements, belies a more fundamental 22-year Hale cycle, named after its discoverer, George Ellery Hale.

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“Sunspot Cycle 25 could have a magnitude that rivals the top few since records began,” Dr. McIntosh said in late April.

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