Small, medium, large: what galaxy sizes reveal about their past

Galaxies are the largest structures of matter in our Universe. Our own Milky Way has been studied in glorious detail. We know it has billions of stars, around most of which planets are likely to be found. There is a super massive black hole at its center where anything that gets too close will be consumed. There are intricate dust lanes that obscure the main disk of the galaxy. There is the life-force of stars, hydrogen gas. Finally, there is the mysterious dark matter that acts as a gravitational glue holding the ordinary matter together. But our galaxy is just one of many, and since their discovery, understanding how these complex objects form and evolve has been a focus of astronomers. There are many pathways to reveal more about the nature and evolution of galaxies. In this talk, Dr Rebecca Allen from the Centre for Astrophysics and Supercomputing, will share how she uses the sizes of galaxies to understand more about their growth. Presented on Friday 12 May 2017.