Assertion: nebula's material | /r/MadeOf | lower 3he/4he ratios
Facets:
value: generally
type: DEGREE
value: from radioactive decay
type: OTHER
Source sentences:
text: The ratio of 3He to 4He within the Earth's crust and mantle is less than that for assumptions of solar disk composition as obtained from meteorite and lunar samples, with terrestrial materials generally containing lower 3He/4He ratios due to ingrowth of 4He from radioactive decay.