A precedent to the recently-discovered pulsed radio sources or ‘pulsars’ exists in our own solar system. Jupiter could be thought of as a very slow ‘pulsar’ having a period of about 10 h or 35 000 s. Like pulsars, this emission period is known to a high order of accuracy (about 1 in 106). One difference is that Jupiter emission is received over an appreciable part of this period (1/4 to 1/2 or more) compared with about 1/30 of a typical pulsar period (about 40 ms in 1.3 s). Both pulsar and Jupiter bursts have a microstructure of the order of milliseconds, suggesting similar sizes of instantaneous emission regions. In both, the intensity observed varies from period to period. Emissions from both have relatively strong circular-polarization components at times.