The Universe's Average Color Is Beige, and It's Been Getting Less Blue

Smear the entire sky into one mix, and what color do you get? According to NASA's Astronomy Picture of the Day, the answer is a conditionally perceived shade of beige — #FFF8E7 in computer parlance. The calculation isn't a single measurement of a single thing; it's a composite tone, which is why the phrasing matters as much as the hex code. The mix has also been shifting. This color has become much less blue over the past 10 billion years, which the APOD explanation attributes to redder stars becoming more prevalent. Read that way, the average color of everything is less a fixed pigment than a snapshot of a changing stellar population: as the kinds of stars lighting up the sky change, so does the tone of the whole picture they make together.