From the March 2002 issue

Universe is beige, not green

Astronomers make a correction to the universe's color scheme.
By | Published: March 23, 2002 | Last updated on May 18, 2023
In January, two astronomers captured the world’s fascination when they announced that the universe’s collective color is a pale shade of green. However, this cosmic tint didn’t sit right with some color scientists, who soon noticed a slight problem with the astronomers’ result. After some reevaluation, it turns out that the universe’s collective color isn’t any shade of green at all, but a dull off-white hue.

Johns Hopkins University astronomers Karl Glazebrook and Ivan Baldry determined what they call the “cosmic spectrum” from mixing visible light from more than 200,000 galaxies observed by the Two Degree Field (2dF) Galaxy Redshift Survey. The effort was designed not to paint a colorful picture of the universe, but to study the history of star formation. They presented the cosmic color purely for fun.

“Our original intention was merely an amusing footnote in our paper,” Glazebrook states. “We admit the color of the universe was something of a gimmick, to try and make our story on spectra more accessible.”

The popular media coverage caught the attention of color scientists as well. They noticed a bug in the software Glazebrook and Baldry used to determine how human eyes would perceive the cosmic spectrum. The software used a non-standard “white point” (the point light appears to be white to our eyes under certain types of illumination). This incorrect setting made the cosmic spectrum’s white point appear rosier than it should have and threw off the resulting cosmic color.

The new color lies somewhere between white and beige. Since announcing their color correction earlier this month, the two Johns Hopkins astronomers have received hundreds of name suggestions for the new color — with “cosmic latte” being a personal favorite, says Glazebrook.

While our understanding of the universe’s overall color may have changed, Glazebrook and Baldry’s science results have not. The cosmic spectrum, which they’re using to analyze past and present stellar populations, is still correct. Additionally, the JHU astronomers are sticking to the idea that the universe started out bluer overall and reddened as stars aged.