Galaxies

This short, accessible overview by Or Graur covers the history, the physics and the scientific uses of galaxies. It is written for readers without a specialist background and shows how modern astronomy works in practice and where this field may be heading. The book begins with two thousand years of galaxy studies. Graur traces them back to Ptolemy's Almagest, which catalogued hundreds of stars and a few hazy, cloud-like objects, one of them the Andromeda galaxy. Among the people readers meet are William Herschel and his sister Caroline, the first professional female astronomer, who found hundreds of galaxies and helped lay the groundwork for modern galaxy research. Lesser-known figures include the tenth-century Persian astronomer Abd al-Rahman al-Sufi and the twentieth-century American astronomer Vesto Melvin Slipher. The book then looks at the kinds of galaxies astronomers observe and the physics behind them, and at the myths and physical structure of our own Milky Way. It explains how galaxies helped researchers discover and study dark matter and dark energy, and how scientists think galaxies formed soon after the Big Bang and developed into their present forms. The final chapter shows readers how they can take part in galaxy studies themselves and help fight the light pollution that hides the Milky Way and all but the brightest stars.