Assertion: dark matter | /r/HasProperty | proposed by jan oort
Facets:
value: in 1932
type: TEMPORAL
Source sentences:
text: Dark matter was first proposed by Jan Oort in 1932 as a reason for the spinning speeds of stars in the Milky Way.
text: Dark matter was first proposed by Jan Oort in 1932 as a reason for the spinning speeds of stars in the Milky Way.