Assertion: sky | /r/HasProperty | black
Facets:
value: night
type: TEMPORAL
value: always
type: DEGREE
value: as in the case of mercury
type: OTHER
Source sentences:
text: The Moon's atmosphere is negligibly thin, essentially vacuum, so its sky is always black, as in the case of Mercury.
text: None of Jupiter's moons have more than traces of atmosphere, so their skies are black or very nearly so.
text: Triton, Neptune's largest moon, has an atmosphere, but it is so thin that its sky is still black, possibly with some pale haze at the horizon.
text: If you could keep going higher in a rocket, you would see the sky become darker and darker until finally the sky would be black because you have left the earth's atmosphere.
text: If you were on the Moon, which has no atmosphere, the sky would be black both night and day.