Assertion: pulsar | /r/HasAspect | period
Facets:
Source sentences:
text: Therefore, the neutron star isn't spun up to such high frequencies; in fact, some pulsars that are in high-mass systems have periods longer than 1000 seconds.
text: Subsequent observations, however, established that pulsars have periods that increase extremely slowly.
text: Subsequent observations, however, established that pulsars have periods that increase extremely slowly.