The Concept of the Sun, 1900-1910.

ABSTRACT:

The source of solar energy had been a persistent problem, even called the greatest of all, yet there were no serious attempts to solve it in the first decade of the 20th century despite the announcement of a potential solution in the form of radioactive heat in 1903. The delay in addressing the solar energy problem is striking because the problem lay within the self-proclaimed area of astrophysicists' research interests, and would have resolved a contradiction in the age of the sun as allowed by gravitational contraction theory, and as required by biological and geological theories.

I explain the delay in addressing the problem by providing a cognitive history of the concept of the sun during the period 1900--1910. I show that astrophysicists used multiple, only loosely-connected concepts of the sun, none of which shared any properties with the solar energy problem. The questions of the sun's age and source of energy themselves were of very low rank in the conceptual structure of these astrophysicists. Additionally, the proposed solution to the problem through radioactive heating would have required abandonment of the most important aspect of solar research: spectroscopic identification of chemical and physical conditions in the sun.

In my investigation I also demonstrate benefits of using a frame model approach to intellectual history.