Ernst Florens Friedrich Chladni (1756-1827) and the origin of meteorites

Abstract

At the end of the 18th Century, an essay on fireballs, masses of iron or aeroliths that occasionally fell on Earth was published by the German physicist Ernst Florens Friedrich Chladni (1756-1827). In that work, previous conjectures trying to provide an explanation of this phenomenon were refuted, among them several ideas such as processes related to atmospheric humidity, the action of lightning, mergers caused by both forest fires and coal seams, or Moon volcanism. Chladni proposed an alternative theory: the cosmic or extraterrestrial origin of all these materials. His ideas were based on a comparative study among the different existing samples, as well as on the cases which had occurred according to the reports of many eyewitnesses. Chladni considered this phenomenon as being natural in origin, and he implicitly applied the principle of actualism, with which it was possible to explain the past from the present, but also the principle of uniformity of natural laws, both in the space and in the time, with which was possible to stablish a relationship between the structural and mineralogical characteristics of the different samples. Despite the fact that various geochemical works were published in the following years which supported the cosmic origin, the definitive recognition was slow to arrive, even some years after Chladni’s death, but main personalities such as Laplace, Somerville, and Humboldt, among others, had contributed to it. This essay has been considered the most important work in the foundation of Meteoritics. A finales del siglo XVIII, el físico alemán Ernst Florens Friedrich Chladni (1756-1827) publicó un ensayo sobre las bolas de fuego, masas de hierro o aerolitos que ocasionalmente caían sobre la Tierra. En ese trabajo se refutaban conjeturas previas que intentaban explicar este fenómeno mediante procesos relacionados con la humedad atmosférica, la acción de los rayos, fusiones provocadas por incendios de bosques o vetas de carbón, o el volcanismo lunar. Chladni proponía una teoría alternativa: el origen cósmico o extraterrestre de todos estos materiales. Sus ideas se basaban en un estudio comparativo entre las diferentes muestras existentes, y en los casos acaecidos de acuerdo con los informes de muchos testigos oculares. Implícitamente aplicaba a este fenómeno, considerado como natural, el principio del actualismo, con el que era factible explicar el pasado a partir del presente, así como el principio de la uniformidad de las leyes naturales, tanto en el espacio como en el tiempo, lo que permitía relacionar las características estructurales y mineralógicas de las diferentes muestras entre sí. A pesar de que en los años siguientes aparecieron diversos trabajos geoquímicos que apoyaban el origen cósmico, el reconocimiento definitivo tardó en llegar, incluso algunos años tras la muerte de Chladni, con personalidades tan relevantes como Laplace, Somerville y Humboldt. Este ensayo está considerado el trabajo fundacional de la Meteorítica.