Assertion: neutral hydrogen | /r/CapableOf | produce radiation
Facets:
value: at a frequency of 1420.4058 mhz
type: TEMPORAL
Source sentences:
text: He referred this to Hendrik van de Hulst who, in 1944, predicted that neutral hydrogen could produce radiation at a frequency of 1420.4058 MHz due to two closely spaced energy levels in the ground state of the hydrogen atom.