Tidally synchronized solar dynamo: a rebuttal

Abstract

The idea of a planetary origin for the solar cycle dates back to the nineteenth century. Despite unsurmounted problems, it is still advocated by some. Stefani, Giesecke, and Weier (2019) thus recently proposed a scenario based on this idea. A key argument they put forward is evidence that the $\sim$11 years-solar cycle is clocked. Their demonstration rests upon the computation of a ratio proposed by Dicke (1978) applied to the solar cycle time series of Schove (1955). I show that their demonstration is invalid, because the assumptions used by Schove to build his time series force a clocked behaviour. I also show that instabilities in a magnetized fluid can produce fluctuation time series that are close to being clocked.