The role of hydrogen in the evolution of galaxies

Hydrogen gas is one of the main components in a galaxy like our own Milky Way - but we can't see it when we gaze into the night sky. I will take you on a journey of the unseen parts of our Galaxy - and others like it - using sensitive observations taken with Australia's best radio telescopes. I will explain how astronomers use observations of hydrogen gas to determine the history, and predict the future, of galaxies in the universe.