The rise of hydrological science off Earth

SummaryIt has been a long lasting interest to understand the laws that underlie water movement on Earth with the purpose to control it and make use of it. It is now recognized that water is not exclusive to the Earth but, rather, is a major constituent of the matter in the universe and may be a proxy for life in other planets as well. In this paper, we reflect on the need to expand the boundaries of the current water sciences from the description of mere terrestrial hydrological processes to a comprehensive inclusion of the physical laws and processes pertaining to water dynamics off Earth. Are we at the edge of a new scope of hydrology?

► We discuss the need to expand the paradigm of terrestrial hydrology to the environment outside Earth.
► The assumption of closed terrestrial hydrologic cycle is relaxed to include exchange with the open extraplanetary space.
► We review astrophysical processes related to water genesis, movement and recycling in the universe.
► A coherent set of hydrological processes is depicted in a unique frame defining the components of astrohydrology.