Assertion: moon's mass | /r/CapableOf | form ring
Facets:
value: around mars
type: LOCATION
Source sentences:
text: The moons of Mars may have started with a huge collision with a protoplanet one third the mass of Mars that formed a ring around Mars.
text: The fraction of the mass of Phobos that will form the ring depends on the unknown internal structure of Phobos.