Assertion: black hole | /r/HasProperty | observed
Facets:
value: indirectly
type: MANNER
value: from afar
type: MANNER
Source sentences:
text: Black holes can be observed from afar
text: Black holes can’t be observed because nothing, not even light, can escape from their boundaries, known as the event horizon, because the gravity is so strong.
text: A black hole could also be observed indirectly, by measuring its effect on the stars whirling in the cluster core.