The Analysis of Starlight ' 



By Bernard Pagel 



Royal Greenwich Observatory, Sussex, England 



[With 7 plates] 

 INTRODUCTION 



Astronomy is a branch of science that enjoys a universal fascination. 

 One of the reasons why it fascinates people is that the sheer romance 

 of the night sky never palls even for the most hardbitten observer — 

 at least in the warm and comparatively short nights of the smnmer. 

 In winter it has to be admitted that observing is not quite so romantic 

 after one has been at it for six hours or more, but there are always 

 enough interesting things in the sky itself to compensate one for the 

 ejffort. Another fascination exerted by astronomy is the literally 

 uneartlily appearance of the moon, the planets, star clusters, and 

 nebulae seen through a small telescope or even a good pair of bi- 

 noculars; then also there is the possibility of the existence of other 

 worlds, some of which may for all we know be inhabited by in- 

 telligent beings, and all the exciting prospects of space exploration 

 by automatic instruments or even by human astronauts, which are 

 being brought a step further from science fiction and a step nearer to 

 reality practically every day. 



But astronomy also has a special appeal of its own on more strictly 

 scientific grounds than these. The Ancients believed the heavenly 

 bodies to be incorruptible and not subject to the laws governing 

 our unhappy sublunary world, and our present belief that the same 

 physical laws apply in the heavens as on the Earth is really a new 

 and still staggering idea that goes no further back into history than 

 the Newtonian revolution in science. The first applications of this 

 idea were to the study of the motions of planets, comets, and, later 

 on, double stars in the light of Newtonian mechanics ; and it was not 

 until the middle of the 19th century that the spectroscopists got to 

 work, starting with the discoveries of Kirchhoff and Bunsen, and 



^Reprinted by permission from The Advancement of Science (London), vol. 19, No. 82, 

 March 1963. 



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