“An astrophysicist’s nightmare: When we thought we understood it all, the Universe chose to disagree”
Star clusters, large groups of up to millions of stars, are the basic building blocks of the galaxies in which they are formed and evolve. Understanding star cluster formation and evolution is therefore of fundamental importance to understand how galaxies form, evolve and transform on cosmic timescales. At the beginning of this century, we thought that we understood how stars preferentially formed in star clusters, and how star clusters, in turn, made up the stars in their host galaxies. It was firmly believed that all stars in a star cluster were formed at the same time, with very little variation in chemical properties. Perhaps we had become too arrogant or complacent, but Nature decided to teach us that we didn’t quite understand how the Universe worked in any detail. Join us for an in-depth look at what changed once we started to use new and better instrumentation and how an almost dormant field became a hive of activity and new discoveries, upending many established ideas along the way.