Galaxies: A Very Short Introduction

Galaxies are the building blocks of the Universe: standing like islands in space, each is made up of many hundreds of millions of stars in which the chemical elements are made, around which planets form, and where on at least one of those planets intelligent life has emerged. Our own galaxy, the Milky Way, is just one of several hundred million other galaxies that we can now observe through our telescopes. Yet it was only in the 1920s that we realised that there is more to the Universe than th…