Assertion: black hole's size | /r/HasProperty | confirmed by interferometry
Facets:
value: by observing the speed
type: MANNER
Source sentences:
text: The small sizes were confirmed by interferometry and by observing the speed with which the quasar as a whole varied in output, and by their inability to be seen in even the most powerful visible-light telescopes as anything more than faint starlike points of light.