Source:http://linkedlifedata.com/resource/umls/id/C1551080
NCI: A unit of length that would be traversed in a period of one year by an object moving at the speed of light in a vacuum (2.99792458E8 meters per second). One light year is equal to 63239.7 astronomical units, 0.3066 parsecs, 5.88E12 miles, or 9.460528405E15 meters.,HL7V3.0: <p>1 [c].a_j</p>