Comet Controversies

Abstract

Even if comets may not be guilty of mass extinctions, they have certainly been the subject of some hypotheses of varying degrees of weirdness. Among twentieth century researchers into comets and associated phenomena, the name S.K. Vsekhsvyatskii looms large. His analysis of the changing brightness of comets as they approach and recede from the Sun enabled him to estimate an average rate of response to the changing degree of solar radiation which is still widely used in making brightness forecasts for these objects, even though more recent alternative values are increasingly taking over from what had long been considered as Vsekhsvyatskii’s standard. Nevertheless, his research into the way comets respond to their distance from the Sun resulted in one of the most comprehensive descriptive catalogues of historical comets available until recent years, published in his book Physical Characteristics of Comets and later supplements, which has proved invaluable both to researchers of comets and to historians of astronomy.