Champaign, IL — What are stars? How do they shine? How are stars born and what makes them die? How do stars relate to the Sun and to the inhabitants of Earth?
Answers may be found in “The Little Book of Stars,” written by University of Illinois astronomer James B. Kaler and recently published by Copernicus Books. In this book – his seventh – Kaler brings the subject of stars down to Earth for the general reader. In clear, precise and light-hearted prose, he explains how astronomers have come to understand our distant stellar companions.
The only thing “little” about the book is its size – a convenient 5 by 7 inches. The 184-page book goes the distance, from the Big Bang to Earth. After describing what stars are, Kaler uses them to provide a revealing look at the extraordinary physical forces at play in the Universe.
“Like raindrops from a thundercloud, [stars] are the condensates of the Big Bang,” Kaler writes, in describing the event that gave birth to the Universe.
Stars come in immense variety, from those as small as a city to those that would swallow much of the Solar System, from those that shine feebly with a millionth of the power of the sun to those a million times brighter. There are cool red stars, hot blue stars, faint brown dwarfs and invisible black holes. The significance of stars to human life is the thread that runs constantly through the book.
Ancient societies grouped the brighter stars into constellations, “partitioning the celestial vault into smaller units, allowing stars and many other kinds of astronomical objects to be recognized and named,” Kaler wrote. Among those objects are planetary nebulae, pulsars, supernovae and variable stars. There also are double stars, multiple stars and huge clusters of stars; all assembled into galaxies.
“Our Galaxy – a disk-shaped structure that manifests itself at night as the Milky Way – is 80,000 light years across; entire ice ages can come and go while light travels from one side of it to the other,” Kaler wrote. “In the depths of space, we find countless more galaxies, trillions of them, assemblies in which billions of stars can be caught together in a single glance.”
Kaler takes the reader full circle, explaining how the gas and dusty particles in the interstellar medium are drawn together to form stars; how thermonuclear reactions deep in the stellar interior – an alchemist’s cauldron – change hydrogen into other essential elements; and how matter blown from stars, either in quiet winds or violent explosions, returns dust and chemically enriched matter back into the interstellar medium where new stars eventually will be born.
“Through a variety of interactions, the lives of the stars led to the birth of one in particular,” Kaler wrote, “the one that brings daylight, the one that gave us birth, the one that made the study of the stars and of the Universe possible in the first place.”