Astronomers have determined the average color of the universe is a shade of beige known as Cosmic Latte. Derived from the light of 200,000 galaxies in the 2dF Galaxy Redshift Survey, the hue reflects the evolving mix of stellar populations over the last 10 billion years.
The question of what color the universe would be if the entire sky were smeared out began as a whimsical inquiry into the types of stars common in nearby galaxies. According to NASA, the result is a conditionally perceived shade of beige, identified in computer parlance as #FFF8E7.
The 2dF Galaxy Redshift Survey and the Math of Beige
To reach this conclusion, researchers computationally averaged the light emitted by a massive sample of galaxies. Specifically, Karl Glazebrook and Ivan Baldry of JHU used data from the 2dF Galaxy Redshift Survey, which measured spectra for more than 200,000 galaxies. While the resulting cosmic spectrum contains emissions across all parts of the electromagnetic spectrum, it resolves into a single composite color for human perception.
This process is not as simple as mixing paint. A spectrum separates light by wavelength; instead of recording only how bright a galaxy looks, spectroscopy shows how much light arrives at different wavelengths and reveals information about stars, gas, dust and redshift. By combining information from the galaxy sample, the researchers constructed a representative spectrum of the local Universe’s visible light, which was scientifically useful for studying stellar populations and the history of star formation.
To turn this raw spectrum into a visible color, astronomers must use models of human color perception and define a specific viewing environment or white point. A spectrum is not itself a paint swatch; to display one representative colour, measured wavelengths must be processed under defined viewing assumptions.
Correcting the Turquoise Error
The path to Cosmic Latte included a notable scientific correction. An early version of the calculation suggested the universe was a pale turquoise or green. However, color scientists identified flaws in the viewing assumptions and conversion methods used at the time.
As Supereducational explains, this correction did not invalidate the underlying galaxy spectra or the scientific analysis of the stars themselves; it merely changed how that data was interpreted as a color. Once the assumptions were corrected, the hue shifted to the warm off-white beige now recognized as Cosmic Latte.
Stellar Evolution and the Shift from Blue to Red
The average color of the cosmos is not a static constant; it is a record of stellar history.
This shift occurs because the population of stars changes over time. Young, hot stars emit more blue light, but these massive stars are short-lived. As they die out, longer-lived red stars begin to dominate the galaxy populations, shifting the integrated spectrum toward redder wavelengths. This makes the beige hue a proxy for the history of star formation in the local universe.
Common Misconceptions About Cosmic Latte
Because the term average color of the universe is often used in headlines, several misconceptions have taken root.
- Empty space is not beige: Cosmic Latte is the combined light of galaxies, not the color of the vacuum of space.
- Not every galaxy is beige: Individual galaxies vary wildly based on their dust content and stellar populations.
- The green result wasn’t a failure of data: The initial turquoise result was a conversion error, not a failure of the spectral measurements.
The name itself emerged from a contest to find a more descriptive label than technical jargon. While entries like skyvory and univeige were considered, NASA reports that Cosmic Latte was the winner.
While the #FFF8E7 hex code provides a digital representation, the actual perceived color can still vary depending on display calibrations and the wavelength ranges used in different surveys. This leaves a lingering technical question: would a different survey with different redshift cuts produce a slightly different shade of latte?