Under "Cosmic latte" (a shade of white):
In 2001, Karl Glazebrook and Ivan Baldry determined that the color of the universe was a greenish white, but they soon corrected their analysis in "The 2dF Galaxy Redshift Survey: constraints on cosmic star-formation history from the cosmic spectrum", published in 2002. In this paper, they reported that their survey of the color of all light in the universe added up to a slightly beige white. The survey included more than 200,000 galaxies, and measured the spectral range of the light from a large volume of the universe. The hexadecimal RGB value for Cosmic Latte is #FFF8E7.and
What the study revealed is that the overwhelming majority of stars formed about 5 billion years ago. Because these stars would have been "brighter" in the past, the color of the universe changes over time shifting from blue to red as more blue stars change to yellow and eventually red giants.
omgggggg, this rules.