What is the color of all light in the universe? The answer was found in 2002: Cosmic Latte.
An unconventional question, but certainly not uninteresting! Researchers, led by Ivan Baldry and Karl Glazebrook, used spectral analysis to survey more than 200,000 galaxies to research star formation (one of the largest samples ever taken). Spectral analysis gives a range of light frequencies for whatever celestial object you are studying.
The spectral analysis of all these stars allowed for an average to be taken to determine the color of the universe. A miscalculation in 2001 led the researchers to believe the color to be a “cosmic turquoise”, but this was quickly corrected the next year.
The name was decided from a list of suggestions by the public. “Cosmic Latte” itself was coined by one Peter Drum. Reading about the color in the Washington Post, he noticed the color was the same as the latte before him. Other potential names suggested include: Univeige, Skyvory, Astronomer Almond, and Primordial Clam Chowder.
However, the color of the universe will not always be Cosmic Latte. As the universe ages, more and more stars will be older, shifting from blue (e.g., Zeta Puppis) to yellow (e.g., our sun) to red (e.g., Gliese 623). This means the color of the universe is also shifting towards the red end of the spectrum.