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Letter: Spotted history

Published 7 July 2010

From Frank Goodman

Climate sceptics are prone to ignore indicators of global warming when it suits them, but their protagonists can be guilty of a similar process – suggesting particular research is “flawed” or, worse, by making personal attacks on the researcher.

Stuart Clark did not mention Theodor Landscheidt‘s research when describing David Hathaway’s work in his article on sunspots (12 June, p 30). This would have cleared up the mystery behind the sun’s present lack of get-up-and-go. Landscheidt’s work on the effect of the solar system’s centre of gravity, or barycenter, on the sun’s heat output predicts that Earth will cool until about 2030.

Whether this will overcome the general warming trend, however, is unclear. When this was mentioned to a global-warming guru recently, the reply was that Landscheidt was not to be trusted as he was an astrologer. Then again, so was Kepler.

David Hathaway writes:

• There are many papers that claim to explain solar activity cycles based on planetary motions, the earliest I know of is by Rudolf Wolf in 1859. Many people have noticed that Jupiter’s orbital period is close to that of the sunspot cycle. In a paper in Solar Physics in 1999, Landscheidt tried to connect planetary motions to the solar cycle. He predicted that the next maximum would be in 2011, which seems unlikely at this point.

One of the problems with these studies is that planetary motions are very predictable, whereas the solar cycle is stochastic and chaotic. Additionally, the studies rely on statistics, not physics. Any calculation of the actual forces on the internal dynamics of the sun due to planetary motions shows that they are tiny compared to the buoyancy, Coriolis and magnetic forces that play active roles in the solar activity cycle.

From Des Fourie

The relationship between sunspot activity (or the lack of it) and droughts in southern Africa has been investigated by Will Alexander and others (Journal Of The South African Institution Of Civil Engineering, vol 49, p 32).

Not withstanding the problems of global warming, they warn of the inability of current climate models to grasp the relationship of this cyclical phenomenon to stratospheric and tropospheric climate behaviour. The same paper posits a relationship and possible cause of sunspot activity to the “acceleration and deceleration of the sun as it moves through galactic space”, and the planets’ paths around the sun.

Johannesburg, South Africa

Nottingham, UK

Issue no. 2768 published 10 July 2010

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