140 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946 
Eddington has pointed out that with our new knowledge of a new 
physics we might have predicted the existence of the stars from the 
general properties of matter, even if we had been hopelessly cloud- 
bound and had never seen them. The atomically small leads directly 
to the sidereally immense. Analogously, we could now propose half a 
dozen problems dealing directly with the local solar system, the solu- 
tion of which would go far toward settling the most basic problems 
of universal cosmogony. 
The preceding remarks are prefatory to the observation that an 
astronomer who is especially interested in the macrocosmos is in 
congenial company when he associates with a geologist who explores 
the origin of meteorites, the topography of the moon, and the atmos- 
phere of.planets, and writes on such subjects as “Our Mobile Earth” * 
and “The Strength and Structure of the Earth.” ¢ 
HOT GAS AND COLD SPACE 
A factor of high importance in general cosmogony, as well as in 
the contemplation of the surface rocks of the earth, is the greediness 
with which interstellar space sucks the life blood out of the stars. 
Or to put the same idea in prosaic and less anthropomorphic terms, 
the second law of thermodynamics, which records that heat flows in. 
the direction of lower temperature, is a most basic principle in sidereal 
evolution. 
The temperature of interstellar space is a little above absolute zero; 
the temperature of the stars, except in their relatively thin and cool 
atmospheric blankets, is in the tens of millions of degrees absolute. 
Hence the stars cool off violently. The violence is not perceptible 
to the average observer, unless he be equipped with long-range cosmic 
vision and competent theory. But the astonishing rate with which our 
own star pours its heat into the vacuum of interstellar space would 
scarcely permit time for the evolution of the observer and his ancestral 
line of living forms, if it were not for the existence of a mechanism 
for the subatomic replacement of the heat so profusely radiated. 
In a few scores of millions of years the heat of an average star would be 
disastrously diminished—disastrous for neighboring protoplasmic 
life—if the expenditure were not prolonged a thousandfold by the 
“carbon stove” mechanism, which burns stellar hydrogen fuel into 
helium ash while liberating energy, and by similar atomic trans- 
formations.® 
3Daly, R. A., 1926. Scribner's, New York. 
*Daly, R. A., 1940. Prentice-Hall, New York. 
5 Nontechnical accounts of these atomic transformations can be found in Gamow, The 
birth and death of the sun, The Viking Press, New York, 1940; and Russell, Sci. Amer., vol. 
161, pp. 18-19, 1939. 
