This book is aimed at the general reader interested in understanding how modern astronomy advances in a steadily growing comprehension of galaxies. It is written from the perspective of observational astrophysics, highlighting how observations have consistently opened new horizons.
Initially, it provides a brief historical overview of how our Galaxy was mapped until the development of large telescopes, demonstrating how we recently realized that our Galaxy is not the entire universe but just one of billions of similar systems. You will learn how we now measure the size of our Galaxy and what its structure is: disk, bulge, bar, halo, streams of stars as our Galaxy assimilates smaller neighbors, and the supermassive black hole at its center.
The author then expands on the description of the local group of galaxies, including our Milky Way, the Great Nebulae, the Andromeda Galaxy, and the cloud of local dwarf galaxies. The next step extends focus to nearby galaxy clusters, such as the Virgo Cluster, and explores how galaxies are classified based on their shape and structure: spiral, elliptical, and irregular. We discover the star populations that comprise galaxies, and an interesting aspect shows how local galaxies can help us understand the history of the entire universe — an exciting research area called "near-field cosmology".
As we broaden our focus beyond local galaxy groups, readers will learn how astronomers map the structure of the universe as determined by the large-scale distribution of galaxies — sheets, filaments, and voids. An overview is provided of galaxy evolution based on the current cosmological model, including present uncertainties. We see how the model can be tested through observations.
In the penultimate chapter, the author gives us an overview of the astronomical techniques and tools available across the entire electromagnetic spectrum, from radio waves to gamma rays, from ground-based and space-based observatories, showing how the information discussed in previous chapters is obtained. The journey concludes with a look at exciting developments in instruments that will enhance our knowledge of galaxies throughout the universe in the next decade.
"What I love about this book is that it provides visual images of what is really happening in galaxies. ... many images and stories. ... So, if you want to understand how the Big Bang led humans, you might want to read this book."
John C. Mather
Nobel Laureate in Physics, 2006.
