In one of the most comprehensive multi-observatory galaxy surveys yet, astronomers find that galaxies like our Milky Way underwent a stellar “baby boom,” churning out stars at a prodigious rate, about 30 times faster than today.
Our Sun, however, is a late “boomer.” The Milky Way’s star-birthing frenzy peaked 10 billion years ago, but our Sun was late for the party, not forming until roughly 5 billion years ago. By that time the star formation rate in our galaxy had plunged to a trickle…
Astronomers don’t have baby pictures of our Milky Way’s formative years to trace the history of stellar growth. Instead, they compiled the story from studying galaxies similar in mass to our Milky Way, found in deep surveys of the universe. The farther into the universe astronomers look, the further back in time they are seeing, because starlight from long ago is just arriving at Earth now. From those surveys, stretching back in time more than 10 billion years, researchers assembled an album of images containing nearly 2,000 snapshots of Milky Way-like galaxies.