THE NEW OUTLOOK IN COSMOGONY? 
By J. H. JEANS 
Astronomy has always stood aloof from the other sciences; her 
field of research is apart, her methods are entirely her own, and, 
most significant of all, her results have different values from those 
of other sciences. While these reward mankind by utilitarian gifts, 
new methods for the production of wealth, the increase of pleasure 
or the avoidance of pain, astronomy has so far given us only food 
for intellectual contemplation. This is preeminently true of cos- 
mognony, the branch of astronomy which is concerned with the prob- 
lem of how the astronomical bodies come to be where they are and 
as they are. 
From the practical standpoint, the outstanding difference between 
astronomy and the other sciences is the difference of scale. Most 
sciences progress by pursuing nature into the realms of the infinitely 
small, but for astronomy and cosmogony progress les in the direc- 
tion of the infinitely great, or, to be more exact, of the unthinkably 
great. For we now know with fair certainty that there is no in- 
finitely great. A number of considerations combine to show that 
the universe is finite, and it is just because we know this, and are 
beginning to discover the actual limits to the size of the universe, 
and to its duration in time, that the present position in astronomy 
and cosmogony is of quite unusual interest. These sciences stand 
to-day somewhat in the position in which geography found itself 
when the world had been circumnavigated and the limits of what 
remained unexplored first begun to be known. 
It was not until 1888 that the distance of a star was measured, 
-and the scale of structure of the universe revealed. In that year 
three astronomers, Bessel, Henderson, and Struve, independently 
measured the distances of three different stars. In each case the 
method employed was the “ parallactic”” method: the motion of the 
earth in its orbit causes the near stars to appear to move against the 
background formed by the remote stars, and from observations of 
the amount of this apparent motion the distances of the near stars 
can be deduced. But it has long been clear that the majority of 
1Reprinted by permission from The Nineteenth Century and After, Vol. XCVIII, No, 
586, December, 1925, 
151 
