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

The sunspot cycle has appeared to average 11.2 years in length, and has been called the 11-year cycle.

From Project Gutenberg

The last sunspot cycle had the highest maximum of any since 1780, but the present cycle bids fair to set an all time record.

From Project Gutenberg

Also the present sunspot cycle started its rise to maximum about 1954.

From Project Gutenberg