The Milky Way Diet

Our Galaxy's Just-Right Consumption Habits

I'm not a fan of candy bars, but I do know that Milky Way bars (created 102 years ago by Frank Mars) were made to be eaten. By contrast, our Milky Way Galaxy, formed about 12 billion years ago, was made to eat. In at least one sense, the familiar adage, "You are what you eat," applies to both people and galaxies.

The various star populations within a galaxy tell astronomers what a galaxy's "diet" and "eating habits" have been throughout its multi-billion-year history. This information about the when,what, and how much our Milky Way Galaxy has consumed since its...