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Distributed for Reaktion Books

Planet Hunters

The Search for Extraterrestrial Life

Translated by Andy Brown

Distributed for Reaktion Books

Planet Hunters

The Search for Extraterrestrial Life

Translated by Andy Brown
Astronomers are on the verge of answering one of our most profound questions: are we alone in the universe? The ability to detect life in remote solar systems is at last within sight, and its discovery—even if only in microbial form—would revolutionize our self-image. Planet Hunters is the rollicking tale of the search for extraterrestrial life and the history of an academic discipline.

Astronomer Lucas Ellerbroek takes readers on a fantastic voyage through space, time, history, and even to the future as he describes the field of exoplanet research, from the early ideas of sixteenth-century heretic Giordano Bruno to the discovery of the first exoplanet in 1995 to the invention of the Kepler Space Telescope. We join him on his travels as he meets with leading scientists in the field, including Michel Mayor, who discovered the first exoplanet, and Bill Borucki, principal investigator for NASA’s Kepler mission. Taken together, the experiences, passion, and perseverance of the scientists featured here make the book an exciting and compelling read.

Presenting cutting-edge research in a dynamic and accessible way, Planet Hunters is a refreshing look into a field where new discoveries come every week and paradigms shift every year.

248 pages | 3 halftones | 5 1/2 x 8 1/2

Physical Sciences: Astronomy and Astrophysics

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“In this delightful scientific chronicle of humanity’s quest for ‘other worlds’, astronomer Lucas Ellerbroek mixes memoir, history and meetings with remarkable planet hunters.”


“Are we alone in the universe? In Planet Hunters, Lucas Ellerbroek traces the story of this question from its beginnings during the age of Copernicus and Galileo to the present day, teaching us the relevant science as he goes. Ellerbroek is particularly skilled at inserting the ‘astronomy backstory,’ giving accessible introductions to both historical ideas and cutting-edge research, and showing how big questions are teased into empirical science.”


“Ellerbroek examines how the first astronomers gazed at the stars—with the naked eye and then with early telescopes—and shares their thoughts and discoveries. As he does, he provides great examples to help readers understand the immense distances in space and the difficulties inherent in studying the ‘wobbles’ of stars and planets so many millions of miles away. . . . Meticulous and well-researched, but not dull, Planet Hunters is infused with the enthusiasm of the many people who have devoted their lives to searching for a potential neighbor in the enormity of space.”

Shelf Awareness

“It seems as though we’re discovering new exoplanets regularly, but one thing we haven’t found yet is life on them (let’s be real: That is probably going to take a very long time). But that doesn’t mean we’re not looking. Astronomer Ellerbroek takes readers on a journey through the history of looking through telescopes and searching for exoplanets, discussing the discovery of the first in 1995. It’s the history of exoplanets and a search for alien life, speaking with some of the people at the frontiers of this field.”

Unbound Worlds, Best Summer Books of 2017

Planet Hunters traces the history of exoplanet discovery back to a time when the idea of planets beyond our solar system was just science fiction—or heresy. Ellerbroek describes the field of exoplanet research in all its historical context, from Giordano Bruno's heretical burning at the stake for suggesting that stars had planets of their own, to Bill Borucki's dedication to making the Kepler mission a reality. By uncovering the centuries of courage and creativity it took to make revolutionary discoveries in astronomy, Ellerbroek hopes readers will feel less intimidated by the sciences and more encouraged to innovate.”

Doris Elin Salazar |

"One of the best science books of the year. . . . The only planets known to exist in the universe twenty five years ago were the Earth and its near neighbors circling the sun. That all changed with the discovery of the first 'exoplanet' around another star; today, thousands have been catalogued. This lively volume reveals the human face of the researchers who search for the ultimate prize: proof of extraterrestrial life."

Sunday Times

"One of the must-read space books of 2017."

“This book describes the discovery during the last twenty two years of an increasing number of exoplanets—nearly three thousand by the summer of 2016—and this is in itself a fascinating story. . . . Ellerbroek’s book is entertaining and contains much interesting information about important new astronomical techniques.”

The Observatory

"The author writes in an elegant, readable style that offers sufficient technical insight for the non-astronomer, but places the scientists and their work in an appropriate societal and human context. . . . The author has succeeded in bringing this exciting field to a wider audience with a very relaxed style that still pays due diligence to scientific rigor. The real appeal of the book is the human face the author gives to the pursuit of scientific knowledge."


“Ellerbroek describes this voyage of discovery with enthusiastic energy.”

NRC Handelsblad

"From the burning of Giordano Bruno in 1600 for stating the universe was infinite to the launching of the Kepler satellite in 2009, this book recounts the search for planets outside the Solar System, known as exoplanets. Ellerbroek blends history and personal interviews with today's leading researchers, resulting in a uniquely personable approach that does not skimp on science. . . . This is an excellent read for anyone interested in exoplanet research and the astronomers who pursue it. A thorough list of references and chapter bibliographies provide direction for serious readers, though the text is accessible enough for the general reader as well. . . . Highly recommended."


Twenty years ago, humankind did not know whether most stars have planets or whether our Sun was unique with its array of orbiting planets. Today we know that most stars have planets (‘exoplanets’), many of the planets are Earth-size, and that there are billions of Earth-size planets orbiting in the habitable zone where life might evolve. Planet Hunters provides dozens of delightful (and sometimes humorous) histories of individuals who thought and wrote about planets and life around other stars before the recent discoveries provided facts. . . . Planet Hunters is both informative and a pleasure to read. I highly recommend it.”

William J. Borucki, Kepler Principal Investigator, NASA Ames Research Center

“Two dozen years ago, we didn’t know of any planets beyond the ones orbiting our own Sun. Since then we’ve learned that planets are as common as roof tiles. Ellerbroek has written a captivating, up-close-and-personal chronicle of this remarkable burst of discovery. Millennia from now, when the twenty-first century is no more than a footnote, our era will still be notable because the scientists described here opened our eyes to a myriad worlds, and quite possibly, a myriad places where life exists.”

Seth Shostak, senior astronomer, SETI Institute

“We are living in an exceptional epoch. Thanks to the development of technology, the ancient dreams of Greek philosophers have become an exciting field of modern astronomy. In this timely book, the characters who have participated in the discovery of these other worlds share their personal stories. Discoveries are made by individuals, thanks to their vision, enthusiasm, and perseverance, and also through friendship, collaboration, and competition. Planet Hunters is a lively fresco of that international endeavor.”

Michel Mayor, discoverer of the first exoplanet and emeritus professor of astrophysics, University of Geneva

“Ellerbroek is the Jacques Cousteau of the universe.”

Jelle Brandt Corstius

“A compelling adventure full of surprising details that show why astronomy is so fascinating.”

Robbert Dijkgraaf, Institute for Advanced Study

Table of Contents

Introduction: New Marbles
1 The Century of Bruno
2 The Little Sand Reckoner
3 An Inquisitive Mind and Defective Sight
4 The Order of the Dolphin
5 The Tenacious Inventor
6 A Planet in Pegasus
7 The Hut in the Car Park
8 Goldilocks and the Red Dwarfs
9 Beer in Space
10 The Space Rebels
11 The Planetary Circus
Glossary of Terms

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