Why does the Sun shine? Today we know the answer to the question and we also know that earlier answers were quite wrong. The problem of the source of solar energy became an important part of physics and astronomy only with the emergence of the law of energy conservation in the 1840s. The first theory of solar heat based on the new law, due to J.R. Mayer, assumed the heat to be the result of meteors or asteroids falling into the Sun. A different and more successful version of gravitation-to-heat energy conversion was proposed by H. Helmholtz in 1854 and further developed by W. Thomson. For more than forty years the once so celebrated Helmholtz-Thomson contraction theory was accepted as the standard theory of solar heat despite its prediction of an age of the Sun of only 20 million years. In between the gradual demise of this theory and the radically different one based on nuclear processes there was a period in which radioactivity was considered a possible alternative to gravitational contraction. The essay discusses various pre-nuclear ideas of solar energy production, including the broader relevance of the question as it was conceived in the Victorian era.

中文翻译：

---

太阳能来源，约。1840年至1910年：从气象假说到放射性推测

太阳为什么发光？今天，我们知道了问题的答案，而且我们也知道早先的答案是完全错误的。直到1840年代，随着能量守恒定律的出现，太阳能的来源才成为物理学和天文学的重要组成部分。基于JR Mayer的基于新定律的第一个太阳热理论认为，热量是流星或小行星落入太阳的结果。赫尔姆霍尔茨（H. Helmholtz）于1854年提出了引力-热能转换的另一种形式，并取得了更大的成功，汤姆森（W. Thomson）进一步开发了这种形式。四十多年来，曾经如此著名的亥姆霍兹-汤姆逊收缩理论被接受为太阳热的标准理论，尽管它预测太阳的年龄只有2000万年。在这一理论的逐渐消亡和基于核过程的根本不同的这段时期之间，放射性被认为是重力收缩的一种可能替代方法。本文讨论了太阳能生产中的各种核前思想，包括维多利亚时代构思的问题的更广泛相关性。