CHAPTER V

The Alchemy of the Sun

SUBATOMIC ENERGY AND SOLAR HEAT

THE discovery of the enormous stores of energy that
can be set free in the processes of nuclear transforma-
tion gives us a key to the possible solution of the ancient
riddle concerning the sources of solar radiation. We have,
indeed, already mentioned that the nuclear reactions lead-
ing to the transformation of one element into another are
usually accompanied by a liberation of energy that sur-
passes by a factor of many millions the energy set free in
ordinary chemical reactions between molecules. Thus,
whereas a Sun made of coal would have burned up com-
pletely in fifty or sixty centuries, a Sun that takes its energy
from subatomic sources can keep going strong for billions
of years.

But we also know that the ordinary radioactive ele-
ments, such as uranium or thorium, are not abundant
enough to account for the tremendous energy production
in the Sun*; and we are left with the only possible con-
clusion that the observed liberation of energy must be
due to the induced transformations of the ordinarily stable
common elements. We must therefore imagine the interior
of the Sun as some gigantic kind of natural alchemical
laboratory where the transformation of various elements

* These elements are, however, sufficiently abundant to be mainly re-
sponsible, through the heat they develop, for the fact that the interior of
our globe is still in a state of hot molten lava.

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