  Large telescopes have allowed astronomers to observe galaxies that formed as
early as 850 million years after the Big Bang. We predict when the first star
that astronomers can observe formed in the universe, accounting for the first
time for the size of the universe and for three essential ingredients: the
light travel time from distant galaxies, Poisson and density fluctuations on
all scales, and the effect of very early cosmic history on galaxy formation. We
find that the first observable star is most likely to have formed 30 million
years after the Big Bang (at redshift 65), much earlier than previously
expected. Also, the first galaxy as massive as our own Milky Way likely formed
when the universe was only 400 Myr old (at redshift 11). We also show that
significant modifications are required in current methods of numerically
simulating the formation of galaxies at redshift 20 and above.
