Assertion: planet's star | /r/HasProperty | composed
Facets:
value: almost entirely of hydrogen
type: OTHER
Source sentences:
text: The generally accepted difference is one of formation; stars are said to have formed from the "top down", out of the gases in a nebula as they underwent gravitational collapse, and thus would be composed almost entirely of hydrogen and helium, while planets are said to have formed from the "bottom up", from the accretion of dust and gas in orbit around the young star, and thus should have cores of silicates or ices.