In search of historical roots of the extraterrestrial impact theory, II: two unknown German pioneers from the 1850s, Ludwig Pfeil and Karl Reichenbach

The mid-nineteenth century is not regarded as the time when the theory of extraterrestrial catastrophism developed. However, two German scholars independently introduced original concepts of terrestrial impacts of large celestial bodies at that time. Ludwig Pfeil (1803–1896), a self-educated wealthy landowner, and Karl Reichenbach (1788–1869), an eminent scientist and industrialist, independently proposed in the 1850s that the Earth is an...