Our sun vibrates due to pressure waves generated by turbulence in its upper layers (the layers dominated by convective gas motions). Helioseismology is the name given to the study of these oscillations, which can shed light on the inner workings of the sun. Astronomers often detect brightness variations in other stars whose physical processes make them variable, like the Cepheid variable stars used to calibrate the cosmic distance scale, but it is much harder to detect solar-like oscillations in stars that are driven by convection near the star’s surface (“astroseismology”). Open star clusters are well understood and provide benchmarks for studying stellar evolution, stellar rotation, stellar masses and ages, and many other properties, and so astroseismology would be a valuable addition by providing independent determinations of masses and ages for cluster members. But astronomers have not been able to perform such measurements on main sequence stars in an open cluster—until now.