Gaia galaxy map, image credit: ESA The interstellar medium is not my favorite topic in astronomy. Fundamentally, it is the study of interstellar dust bunnies - those clumps of gas and dust that clog up our skies and block our ability to see more distant stars and galaxies. They don’t vary like the pulsating stars I love most. They don’t have stories that alter how we understand our universe like galaxies and galaxy clusters. The gas and dust between stars are just transient blobs of material - sometimes bright and sometimes dark - that are either released during stellar death or waiting to...