A galaxy's distance can only be determined with any accuracy if a spectrum can
be obtained and its redshift measured. Advances in technology mean that the
record is regularly broken. In 1996, astronomers at the Keck Observatories
discovered an unnamed galaxy in the constellation Virgo with a redshift of
4.38. It was identified only because a quasar happens to lie almost directly
behind it. The spectrum of the galaxy is imprinted in the light received from
the quasar. The translation of a value for redshift into a distance depends on
the overall scale factor adopted for the universe. The researchers who found
the galaxy put its distance at 14 billion light years. Its light certainly set
out when the universe was only 10% its present age.
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