Throughout the ages, mankind felt and tried to answer the urge to predict events to come. Omens were carefully collected and categorized on Mesopotamian clay tablets; omen-based prediction was developed into an industry in the form of hepatoscopy (analyzing the shape of the liver of a sacrificed animal) and, in later Roman times, of auspicium (watching the flight of the birds). Ancient Greeks often turned to oracles like the Pythia of Delphi. By the late antiquity, the astrological world view was widespread throughout the civilized world, implying that cosmic and terrestrial events were subject to cosmic cycles governed by a variety of (planetary) periods.
Today we tend to smile at these “superstitious” early attempts. Yet, ironically, many of the “advanced” methods we have for the prediction of solar activity are based on principles that hardly differ from those listed above: just substitute “precursor” for “omen”, “neural network” for “oracle” or “harmonic analysis” for “cosmic cycles”…
But in parallel with the often naïve phenomenological or empirical prediction attempts, already in the Hellenistic world, a handful of enlightened scientists started the development of physical models, based on logic and experience, that would lead to the advanced predictive skills of many models of modern science (Russo, 2004). Extending the analogy, we can see that the real importance of the recent debut of model-based solar cycles predictions is not their still dubious success rate but the conceptual leap they represent.
Despite the rather poor overall performance of solar cycle prediction attempts, the extensive efforts invested in this endeavour were not in vain as they have contributed and keep contributing to a better understanding of the physical processes governing the solar cycle and to constraining the dynamo.
Living Rev. Solar Phys. 7, (2010), 6
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