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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 (Solar Phys.294, 60, 2019) thus recently proposed a scenario based on this idea. A key argument they put forward is evidence that the ≈ 11 years solar cycle is "clocked", as if it were paced by an accurate clock inside the Sun. Their demonstration rests upon the computation of a ratio proposed by Dicke (Nature276, 676, 1978) applied to the solar-cycle time series of Schove (J. Geophys. Res.60, 127, 1955). I show that their demonstration is invalid, because the assumptions used by Schove to build his time series force a clocked behavior. I also show that instabilities in a magnetized fluid can produce fluctuation time series that are close to being clocked. [ABSTRACT FROM AUTHOR]

The core of my article (Nataf in Solar Phys.297, 107, 2022) was about a flaw in the reasoning used by Stefani, Giesecke, and Weier (Solar Phys. 294, 60, 2019) to demonstrate that the ∼ 11 -year Schwabe cycle is "clocked". To give some background and point out other difficulties, I displayed tidal signals built from a very simple four-planet model. Nicola Scafetta criticizes this simplified tidal model because it assumes circular orbits. This is correct. It seems that he did not notice that I referred to the article of Okal and Anderson (Nature, 253, 511, 1975), who were the first to construct a tidal model that takes into account the actual orbits of these four planets. His comment gives me the opportunity to be more explicit on this question. The main conclusion of my original article does not change: no support for a planetary influence on solar cycles. [ABSTRACT FROM AUTHOR]

For the first time, flow velocity is measured in a vortex of liquid gallium, using the pulsed Doppler shift ultrasonic method. At the top of a copper cylinder filled with liquid gallium, we spin a disk and create a turbulent vortex with a dominant nearly axisymmetric velocity field with little variation in the axial direction. The velocity profiles are shown to be well resolved and in quantitative agreement with earlier observations. Reliable velocity measurements in liquid gallium could be obtained only after serious problems due to the formation of oxides were solved. This work opens the way to performing accurate velocity measurements in other liquid metals; preliminary results for liquid sodium are shown. [ABSTRACT FROM AUTHOR]

Presents a seismological study of the mantle beneath the Bowie hotspot of west of Canada. Revellation of a zone of low seismic velocitites; Delay of 0.15 seconds to the travel time of seismic waves traversing a region approximately 150 kilometers in diameter; Suggestions that a mantle plume is present in the lower mantle with the amplitude of the anomaly implying a temperature contrast of 300 K.

Discusses the relative rotation of the earth's core as compared to the mantle. Description of the inner core; Technique of measuring seismic waves by emitters and receivers to investigate the earth's core; Experiments performed by A. Souriau, Song and Richards, and Vidale et al; Use of the Large Aperture Seismic Array (LASA) in Vidale's study, which made for a higher-resolution technique; Discussion of the findings of Vidale et al.