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Planet Hunters

Planet Hunters: The Search for Extraterrestrial Life

Lucas Ellerbroek
Reaktion Books
267 pp.
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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.

An astronomer and researcher at the University of Amsterdam, Ellerbroek begins by sharing a snippet of overheard dinner conversation among his academic colleagues: “You thought it was difficult to convince people about the theory of evolution? Darwin had it easy. Astronomy—now that’s a dangerous profession!” Thus, the stage is set for a quick introduction to 400 years of researchers, charlatans, and enthusiasts who brought the field to the modern day.

Bounded by technology and limited by political and religious climates, the men and women who pursued the questions of exoplanets and extraterrestrial life throughout history were often unpopular and were sometimes considered downright heretical. As Ellerbroek explains, at the turn of the 20th century, planet hunters “were the darlings of the public, but were dismissed as pariahs by their scientific colleagues.”

The majority of the book is devoted to the rapid developments in planetary science in the past 50 years, with Ellerbroek asking the major influencers driving the search for extraterrestrial life to relive their early years. Thus, rather than merely learning about the latest research, we are treated instead to stories about everything from faulty equipment to a zeitgeist that pushed researchers to cloak their exoplanetary work under generically titled grant requests. Summarizing the daunting challenges Bill Borucki faced during his initial efforts to establish a large-scale star-monitoring system, for example, Ellerbroek writes, “[H]e wanted to mount an instrument that did not yet exist on a satellite he hadn’t yet got and send it up into space on a rocket to continually monitor 10,000 stars with a precision that had never yet been attained on Earth, to find planets for which there was no evidence at all of their existence.”

As a reader, I felt the excitement as incremental progress slowly pulled those who search for habitable planets from the fringes to the limelight, not just giving exoplanetary research solid scientific standing but making it the “party you really want to gatecrash.”

Although the book is about one narrow field of astronomy, it is also about scientific tenacity: teaching the reader how to deconstruct unknowable questions into their testable parts; demonstrating that the limitations of the technology can be worked around or overcome; reminding us that there is great value in pursuing what drives us; and showcasing that patience, passion, and persistence—rather than genius—are necessary ingredients for success. Most important, the work of these planet hunters reminds us that the fear that we may not be able to answer the big questions should not stop us from asking them.

About the author

The reviewer is at Service Robotics & Technologies, Arlington, VA 22202.