Measurements of cosmological distance are of great importance, and any new ways of obtaining information other than via redshift analyses would be very welcome. Kiyoshi Wesely Masui and Kris Sigurdson of the University of British Columbia in Vancouver, Canada, have shown that "standard pings" – short broadband radio impulses such as fast radio bursts (FRBs) – could be used to study the 3D clustering of matter in the universe, even without redshift information, using their dispersion as they travel through plasma in space. Dispersion is an imperfect measure of distance, but it is used routinely for pulsars, and redshifts have their own sources of bias. They show that the distortions due to inhomogeneities are calculable, making this new approach promising, and it could be done using forthcoming wide-field radio telescopes.