You can learn a lot about a galaxy based solely on its color. How old it is, whether it's still producing stars, the age of the stars themselves — these are all questions that a galaxy's color can help answer.
But our position relative to the Milky Way (i.e. the fact that we're actually inside it) means our perception of its true color is skewed. Now at last, astronomers have determined the color of our galaxy as it would appear from an outsider's perspective. So just how milky looking is the Milky Way really?
Well, evidently, it's pretty darn milky — that is to say: it's white. But not just any white. According to Jeffrey Newman and Tim Licquia — who deduced the Milky Way's hue by averaging data from 1,000 similar galaxies — the galaxy resembles the color of a fresh spring snow in the hours shortly after dawn, or "roughly halfway between the light from old-style incandescent light bulbs and the standard spectrum of white on a television."
The answer may sound obvious (it is, after all, called the Milky Way), but it actually isn't, for at least two reasons.
The first is that our position within the galaxy is such that clouds of gas and dust obscure all but the closest regions of our galaxy from view. For years, this has prevented astronomers from getting an idea of what the Milky Way looks like as a whole. "The problem," explains Newman, "is similar to determining the overall color of the Earth, when you're only able to tell what Pennsylvania looks like."
The second is that the Milky Way's color is actually best described as a mix of red hues from the galaxy's core, and blue from its spiral arms. Generally speaking, red corresponds to regions of a galaxy where star formation is rare, while blue indicates where stars are still being born.
"It appears our Milky Way is on the road between those two stages," Newman told the BBC. "Based on the color we find, the rate of formation of stars has been declining over time."
"The Milky way is in a very interesting evolutionary state right now."