Yep. Look at it as 'modulation of a waveform by a second frequency', thus constructive and destructive interference. The Maunder minimum is indeed a reference to an historical 'null' in sunspots, caused by that beating (as above). Because we may be heading into another such period this century, the term has been extended in use to refer to any future long-term null in sunspots. It is unfortunate that whether or not solar activity controls the global changes in warming is now a huge political issue, but clearly its the dominant factor. See, for example: http://www.petitionproject.org/review_article.php The gist is the 'human' issue is whether the extant effects of CO2 warming will mitigate the cooling effect of a new Maunder minimum. If not, despite fears of run away climate heating, the reality will be another 'Little Ice Age' with that new Maunder minimum--if we didn't have the CO2 heating. The prediction is global warming for another 10-15 years, then a decline and plateau, similar to today, for 50-80 years.