Assertion: solar system's moon | /r/HasProperty | discovered
Facets:
Source sentences:
text: Another moon, Miranda, is discovered.
text: It wouldn't be until the mid-1800's that the names of the Galilean moons, Io, Europa, Ganymede, and Callisto, would be officially adopted, and only after it became apparent that naming moons by number would be very confusing as new additional moons were being discovered.