Light years are used to measure interstellar distances. The nearest star to the Sun is Proxima Centauri
at 4.2 light years. At the time this entry was written, the farthest star so far detected produced a
gamma ray burst called GRB 090423. It was discovered at 3:55 a.m. EDT on April 23, 2009 and is 13.035
billion light-years away.