The Power of Comparative Planetology to Decipher the History of Planetary Surfaces

Landforms, shaped by interactions between environmental fluids and geologic surfaces, encode information about hydrology, climate, and the overall environment that may be preserved over geologic timescales. Thus, understanding the mechanics of geomorphic and sedimentary processes that shape the landscapes of planets is key to deciphering their respective paleoenvironmental records. To date, the majority of mechanistic models for surface processes were derived from observations of modern Earth, where life thrives, and from scaled-down experiments. Numerical models help to probe wider parameter spaces than can be achieved on our planet, but they only contain the physical rules that they were designed to honor in the first place. However, the foreign parameter spaces spanned by other planets may lead to phenomena that we do not realize need to be included in our models – the unknown unknowns. Even Earth would have looked alien to any of us before the advent of macroscopic life,…