Stars are the basic units of a galaxy. But they form from gas, which is even more elemental. How star-forming gas moves around in a galaxy shapes star formation, and also shapes the galaxy and how it evolves. Stars form when massive clouds of molecular hydrogen cool and collapse. Densities form, and they gather more gas around them, forming protostars. The protostars continue to accrete gas until eventually, they become so massive that temperature and pressure are great enough to trigger fusion. As multiple young stars form in a cluster, their UV radiation creates stellar feedback, which affects the remaining gas. That's a snapshot of how stars form, and though there are many more details waiting to be understood, it's a helpful overview. But astronomers want to to know more than just how stars form in their clusters. They want to know how quickly these clusters can disperse their natal gas with their stellar feedback, and how quickly their feedback can then affect other nearby gas.…