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Introduction
When I was fourteen years old, I was invited to a “star party” in the little town of Oxford, Ohio, where I grew up. Someone had a six-inch telescope there, and I was immediately entranced by the realization that I could walk outside into a yard and gaze deeply into the universe. It was Saturn that caught my attention at that first star party, but soon I was out in a large cornfield in the back of my own subdivision, night after night, exploring the sky with a simple pair of 7x50 binoculars.
What a spectacular summer of binocular stargazing that was! I knew almost nothing of the sky, and had no telescope. Every new view was a discovery, whether it was scanning along the glistening backdrop of the Milky Way, spotting a star cluster, or coming across a bright and colorful star. I took the first steps in a deep knowledge of the sky that summer, something that too few stargazers now possess, in an era of computerized go-to telescopes.
Soon I wandered my binoculars’ field of view into the Great Square of Pegasus, and across the nearby constellation Andromeda. The glow I encountered there, like a bright hazy star surrounded by an elongated, oval fuzz, I soon learned was a pretty special “deep-sky object.”
I had stumbled onto the Andromeda Galaxy, and as soon as I learned what it was, I also learned to see it with my eye alone under our dark Ohio sky. In fact, for most people, it is the most distant object visible to the unaided human eyes. The Andromeda Galaxy is a galaxy like our Milky Way, located some 2.5 million lightyears away—that’s 57 million trillion kilometers, a long hike. (Under perfect sky conditions, some experienced observers claim to see more distant galaxies like M33 and M81 with the naked eye.)
Until the early 1920s, no one knew what galaxies were. Moreover, they had no idea how large the universe was. For many decades beforehand, “spiral nebulae” were thought to be strange gas clouds within our own galaxy. In the early 1920s American astronomer Edwin Hubble made a breakthrough discovery at Mount Wilson Observatory that led to understanding the fundamental nature of galaxies. Aided by work by Lowell Observatory astronomer Vesto M. Slipher, Hubble and others deciphered the cosmic distance scale, at least to a first approximation. By the late 1920s astronomers and the informed public understood that we live in a universe filled with galaxies and that the Milky Way and the Andromeda Galaxy are just two of them.
As I learned more and more about galaxies, I turned to every book I could get my hands on. I was immersed in these distant objects right away. A small astronomy club called the Astronomical Association of Oxford Ohio was built around chiefly college students in our community, which hosted Miami University in southwestern Ohio. They were looking for a columnist to write about galaxies and other distant objects in the sky, collectively known as deep-sky objects, the stuff beyond our solar system. I started writing a column about my observations, and this led to me starting a little “magazine”—a newsletter, really—produced at first on a mimeograph machine in my father’s chemistry office at the university. Deep Sky Monthly reported on numerous galaxies, and grew over its five-year lifespan to a circulation of 1,000.
This growing interest in observing galaxies coincided with a burgeoning availability of larger telescopes in the hands of amateur astronomers, in what became known as the Dobsonian revolution. John Dobson, a San Francisco area amateur astronomer, pioneered a technique of making large telescopes with inexpensive mirrors, perched on simple mounts that moved up and down and sideways like a battleship gun turret. Larger telescopes in the hands of amateur astronomers meant that more and more people could see fainter and fainter objects for themselves, including numerous galaxies. Interest in observing the sky skyrocketed.
One of the books I discovered early on was Galaxies, a pictorial book with a smartly written scientific text by the great science writer Timothy Ferris. Published in 1980, the book contained numerous beautiful photographs and clever diagrams that showed the structure of our Milky Way galaxy and the universe of galaxies around us in a pseudo-3-D style. I loved this book and it was a big influence on me and my early astronomical interests.
In 1982, fresh from Miami University, I was hired as an assistant editor of Astronomy magazine, the world’s largest publication on the subject, and went to Milwaukee, bringing my small magazine with me. Retitled Deep Sky and now a quarterly, the journal of observing galaxies, clusters, and nebulae reached a peak circulation of 15,000 during its ten-year lifetime. By 1992, our company decided that I shouldn’t spend a quarter of my time on this small magazine, but should put all of my gusto in Astronomy. I became Astronomy magazine’s sixth editor in chief in 2002, and have enjoyed writing about galaxies in one form or another for forty years now.
I still treasure Timothy Ferris’s book as one of my early favorites. But practically everything we know about galaxies has changed in the last forty years. In the back of my mind, I always thought about an update of this book for the next generation, now describing the barred spiral nature of the Milky Way, our far deeper knowledge of the galaxies around us in the Local Group, the large-scale structure of clusters and superclusters in the universe, the ubiquitous nature of black holes, and many more topics that we had just hints of forty years ago.
The result is what you hold in your hand. I invite you to join me in our imaginary spaceship and travel far out into the cosmos to explore an amazing universe that we now know in great detail, and one that forty years ago could hardly have been imagined.
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