Assertion: mercury | /r/HasAspect | a trace of atmosphere
Facets:
Source sentences:
text: Mercury has a weak magnetic field and a trace of atmosphere (one-trillionth the density of the Earth and composed chiefly of argon, neon and helium).
text: Instruments on Mariner 10 discovered that Mercury has a weak magnetic field and a trace of atmosphere - a trillionth the density of Earth's atmosphere and composed chiefly of argon, neon and helium.