sunspot cycle

American  

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.

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Example Sentences

See Examples For:

sunspot cycle

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

From Science Daily ● Nov. 28, 2023

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.

From New York Times ● May 28, 2021

Therefore, strictly speaking, the sunspot cycle does not repeat itself in regard to magnetic polarity until two 11-year cycles have passed.

From Textbooks ● Oct. 13, 2016

Then there is the sun's variability, mostly in the form of the 11-year sunspot cycle.

From Slate ● Sep. 9, 2012

The sunspot cycle is only eleven or twelve years long, and even this short period of activity is inaugurated more suddenly than it declines.

From Climatic Changes Their Nature and Causes by Huntington, Ellsworth