Assertion: astronomer | /r/CapableOf | look in the spectra of the sun
Facets:
value: for evidence of hydrogen gas
type: PURPOSE
Source sentences:
text: When astronomers look for evidence of hydrogen gas in the spectra of the Sun, the planets, and nearby stars, the positions of the spectral features or "lines" due to hydrogen are always in the same pattern, characteristic of hydrogen gas, as seen in the laboratory.