Assertion: krypton's line | /r/ObjectUse | used as official distance of a metre
Facets:
Source sentences:
text: The heaviest stable krypton isotope, krypton 86, rose to prominence in the second half of the last century with a tad over one and a half million wavelengths of its orange-red spectral line being used as the official distance of a metre.
text: The heaviest stable krypton isotope, krypton 86, rose to prominence in the second half of the last century with a tad over one and a half million wavelengths of its orange-red spectral line being used as the official distance of a metre.