The common isotopic heritage of the Solar System, the discovery of Martian meteorites in the snowfields of Antarctica and the wastes of the Sahara: this confirmed a unity of being at the atomic level.
Acceptance that certain land formations were the result of celestial, if sublunar, events, such as meteor impacts, came relatively quickly, aided by the extraterrestrial yet apparently metallic or stony nature of solid debris.
The expansion of geology's domain of study to regions above the surface of the Earth consisted of a process which was both gradual and revolutionary.