Assertion: comet's orbit | /r/HasProperty | established by previous observations
Facets:
Source sentences:
text: Unlike the return of periodic comets, whose orbits have been established by previous observations, the appearance of new comets by this mechanism is unpredictable.
text: Unlike the return of periodic comets, whose orbits have been established by previous observations, the appearance of new comets by this mechanism is unpredictable.
text: Unlike the return of periodic comets whose orbits have been established by previous observations, the appearance of new comets by this mechanism is unpredictable.
text: Unlike the return of periodic comets, whose orbits have been established by previous observations, the appearance of new comets by this mechanism is unpredictable.