eso0339 — Science Release The Colour of the Young Universe 19
December 2003 An international team of astronomers  has
determined the colour of the Universe when it was very young.
While the Universe is now kind of beige, it was much bluer in
the distant past , at a time when it was only 2,500 million
years old. This is the outcome of an extensive and thorough
analysis of more than 300 galaxies seen within a small southern
sky area, the so-called Hubble Deep Field South. The main goal
of this advanced study was to understand how the stellar content
of the Universe was assembled and has changed over time. Dutch
astronomer Marijn Franx , a team member from the Leiden
Observatory (The Netherlands), explains: "The blue colour of the
early Universe is caused by the predominantly blue light from
young stars in the galaxies. The redder colour of the Universe
today is caused by the relatively larger number of older, redder
stars." The team leader, Gregory Rudnick from the Max-Planck
Institut für Astrophysics (Garching