Some organisms on Earth have evolved an endogenous clock as a result of their responses to the rhythmic stimuli present in their living environments. Such ability to periodically regulate their physiological functions is believed to confer on these prokaryotes and eukaryotes a stronger fitness. However, biological, physical and chemical rhythms and their tandems, if they exist, on extraterrestrial planetary bodies are largely unknown. This session aims to gather knowledge about the rhythmic stimuli, regulatory mechanisms and evolution of less-understood light-independent biological rhythms (e.g. tidal rhythm) in organisms in extraterrestrial analogs (e.g. subsurface). We welcome conceptual, observational, modeling and experimental studies that bring new theories, introduce new approaches and spur discussions about these untapped rhythms.