RELIEF FORMS ON PLANETS

The importance of the planetary surface that the authors inhabit cannot be denied through arbitrary academic fads. If a geomorphologist can learn more about the surface of the earth by studying other planetary surfaces, then that extraterrestrial study can no longer be dismissed as an interesting intellectual diversion: it becomes an essential part of geomorphology. Among the many lessons that geomorphology can trace to geomorphologist Grove Karl Gilbert’s example that of studying other planets besides the earth has yet to be fully appreciated. The study of planetary landforms can be considered a part of this trend. In the phenomenal world of interplanetary landscape comparison, that historical extension is measured in billions of years. Geomorphic data on ancient relict planetary surfaces are critical in interpreting the early histories and evolution of planetary surfaces, atmospheres, hydrospheres and biospheres throughout the solar system. The study of planetary surfaces relies heavily on analogic reasoning to reconstruct the complex interactions of processes responsible for the observed landforms.