Scientists have discovered a set of mathematical equations which describe how any sequence of random events, no matter the timescale or regularity, can be used to estimate time. The findings are useful for individuals stranded on desert islands without a watch and researchers trying to uncover the limits of nanoscale clocks in quantum, electronic and biomolecular systems. “For example, could you still measure time precisely even when stranded on a desert island? An observer lacking a clock may record the stochastic sequence of states visited by the system, 𝝈 =𝜎0 →𝜎1 →⋯. Credit: Prech et al 2025, Physical Review X (CC BY 4.0)Lots of physical and biological processes progress via random ‘jumps’ which happen at irregular intervals.