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.
noun, Astronomy. 1. Wolf number. noun, Astronomy. 1. a number indicating the degree of sunspot activity on the sun as a factor of observer idiosyncrasies, the number of sunspot groups, and the number of individual sunspots.
noun 1. one of the relatively dark patches that appear periodically on the surface of the sun and affect terrestrial magnetism and certain other terrestrial phenomena. noun 1. any of the dark cool patches, with a diameter of up to several thousand kilometres, that appear on the surface of the sun and last about a […]
noun 1. any starfish of the genus Solaster, inhabiting cold and temperate waters off both U.S. coasts.
noun 1. a reddish variety of oligoclase feldspar, used as a gem, having a red and bright-yellow play of color. noun 1. another name for aventurine (sense 2)