Assertion: quasar | /r/HasProperty | identified in photographic images
Facets:
value: at visible wavelengths
type: LOCATION
Source sentences:
text: The term quasar originated as a contraction of quasi-stellar [star-like] radio source, because quasars were first identified during the 1950s as sources of radio-wave emission of unknown physical origin, and when identified in photographic images at visible wavelengths they resembled faint star-like points of light.