Assertion: comet | /r/HasProperty | observed
Facets:
value: often
type: TEMPORAL
value: patchily
type: DEGREE
Source sentences:
text: Until the discovery of 'Oumuamua, the fact that no comet with a speed greater than the Sun's escape velocity had been observed was used to place upper limits to their density in interstellar space.
text: Comets have been observed and recorded since ancient times by many cultures.
text: Comets have been observed and recorded since ancient times by many cultures.
text: These comets are often patchily observed, as orbital interactions with the planet often cause comets' orbits to become perturbed, causing them to not be found at the expected position in the sky and subsequently lost.
text: The comet is now too far away to be observed, but it has shown us that different solar systems can produce comets that aren't quite like our own.
text: Comets have been observed and recorded since ancient times by many cultures.