This was a highly readable book, explaining what it takes to make a habitable planet. The tone was friendly and accessible to those of us who don't have degrees in the sciences. I appreciated the author's personal stories and her personal insights woven through the material.

Solid Examination of The Field Of Planet Hunting. This is a solid look at how scientists find extra-solar planets and work to determine what they may be like - compositionally, temperature, whether life (as we understand it) may be possible, etc. Written for a general audience by a US-based Austrian native scientist working at the Carl Sagan Institute, the author clearly knows her stuff, but perhaps the English can be a touch stilted at times. It wasn't enough to distract from the book for me, but there absolutely were a few "huh, weird phrasing" moments. Which happens even with fully native English speakers even in the same country - I'm sure there are Americans reading this review who will question even my own phrasing, and I'm a son of the Southern US to the tune that parts of my family have been on the North American continent since the second generation of Europeans to get here at all.

Overall truly a fascinating book, and Kaltenegger's own experiments sound quite fun and interesting to boot. The only flaw I noticed here was such a small bibliography, which is where the star deduction comes into play. Still, this is ultimately a solidly written depiction of a truly fascinating part of interplanetary science. Very much recommended.

I've always been fascinated by space and this book was right up my alley. I loved reading about all of the new ways we are learning and researching. Thank you Netgalley for my advanced copy.

Kaltenegger's book is easy to read, full of easy to understand information, and uses an easy to read narrative. When I started reading this, I hoped to learn more about the topic, and I was surprised to learn as much as I did. Not only about the science being used to hunt for planets, but also about the area around Earth and what we can learn from our neighbors to help scientists learn about distant and potential planets.
If you are looking to learn more about the science used to discover planets outside of our solar system, then this is a great book to get you started.


Thank you NetGalley and the publisher for the eARC of this work in exchange for my honest review.

Alien Earths is a very candid and well researched book on discovering new planets in the Cosmos.

This book does not over explain and is very readable for the interested in space but not a scientist audience. I enjoyed reading this one.

Booksellers Dr. Lisa Kaltenegger is the the founder of Cornell University's Carl Sagan Institute. This book would be a great hand sell with any of his books.

This digital review copy was provided by the publisher in exchange for a fair and honest review. Huge thanks to Netgalley and St Martins Press books for my review copy!

Alien Earths by Dr. Lisa Kaltenegger is a captivating and timely exploration of groundbreaking research that is revolutionizing our comprehension of the universe in our pursuit to uncover the truth about extraterrestrial life. This book is absorbing, informative, and entertaining, making it a must-read for anyone intrigued by the mysteries of the cosmos.

„I see the world around me from a particularly privileged vantage point, the same view that Carl Sagan, the most famous popularizer of astronomy, must have seen as he wrote his books in this same third-floor office of Cornell’s Space Sciences Building […]. His work has had a profound impact on me and sparked the curiosity and imagination of everyone at the institute that carries his name, and of so many other people,” writes astrophysicist Lisa Kaltenegger, founding director of the interdisciplinary Carl Sagan Institute. This book is both a tribute to the great scientist and a perfect continuation of his life's work.

I was one of the many people influenced by Carl Sagan. I will never forget the first time I read his Cosmos as a teenager. It was a mind-blowing experience that forever changed the way I thought about our place in the universe. And I am happy to say that a new generation now has its own talented science storyteller - and even happier that she is a woman.

You will find much more here than the latest information on the search for the eponymous alien earths. Lisa Kaltenegger puts it into a broader context of astronomy, geology, evolutionary biology, and the history of space exploration. She also mixes it with a memoir of her path to her current prestigious position, and I found those parts particularly inspiring. But I believe that an astronomy novice will find the whole book as enlightening as I found Sagan's work several decades ago.

Thanks to the publisher, St. Martin’s Press, and NetGalley for an advanced copy of this book.

I was provided both an audio and print ARC of this book via Netgalley, all opinions are my own.

Cassandra Campbell is a fabulous narrator, and is one of my favorites. This is my first experience with her narrating a non-fiction audiobook. I'm used to her voicing several different characters within a sci-fi or fantasy book, however she takes great care in ensuring the scientific words are pronounced clearly and correctly and if there is a non-English name or phrase it is also pronounced correctly.

This was a great non-fiction book for anyone interested in science of discovering new planets and the investigation of space. The author does a great job of mixing science, personal, experience, and pop culture in to the book without getting overly scientific. She uses real world examples from her own teaching experience and research and references movies and books that readers may be familiar to explain her points about how scientists go about trying to determine if there might be life on other planets. I felt like it was written as if she was having a conversation with you about her favorite topic which made if very approachable and easy to consume. I've read other books on the topic and it can get very technical and overwhelming very quickly depending on how the science is presented. You can tell the author loves her work and tries to make it fun and wants everyone to see the majesty in the cosmos as she does.

I appreciated that the author took the time to write about her life and accomplishments. She notes that it was not always easy being a woman in STEM, but because she had supportive parents and mentors she has had an impressive career. This book would be the perfect gift for an aspiring young lady taking an interest in a STEM career.

I would have appreciated pictures of some of the things Dr. Kaltenegger was referencing at times or links to Hubble images, as I was following along in the ebook. The cover is fantastic, and I hope the final version that comes out in a few weeks does have images, but the ARC does not.

Overall this is a great, easy to digest look at scientific approach to looking for habitable planets and potential life in the universe.

I think I would have liked Alien Earths a lot better if I hadn’t read three other books about exoplanets. It’s not the author’s fault that she’s writing for a general audience and I’m getting bored because I already know how this goes. However, the unfortunate thing is, if a member of that general audience asked me for a fun book about exoplanets I’m not sure this one would make the list. The author is Austrian, and I presume, therefore, her primary language is German, and while the writing is not bad (and for sure, far far far better than anything I would write in any other language), it is at times stilted and not as smooth as I’d like. Ultimately, I think this book is just fine, but there are better books out there on exoplanets.

Where this book truly shines is in the tantalizing and fleeting descriptions of the author’s own laboratory work. I want more details about how they use lasers and microscope parts to generate spectrographs of lava planets. I want to know how she grows a rainbow of mold in petri dishes to get color fingerprints of different kinds of life. I think the time would have been far better spent giving more detail there instead of going over the same broad outlines of the hunt for exoplanets that I’ve read before.

I received an advance reader copy in exchange for this honest review.

Dr. Kaltenegger’s book explains how scientists find planets outside out solar system and the requirements for those planets to support life in an engaging and accessible manner, starting from our own Earth and solar system and then working outwards. Using helpful analogies, she offers insight on the universe and our place in it, answering the crucial question: why haven’t we found other forms of life in the universe yet?
This is a very good introduction to the topic for anyone who is interested. I did feel that Dr. Kaltenegger’s personal stories were somewhat poorly embedded in the framework of the text and felt disorganized and unrelated to the current topic. If it had been managed more carefully I think I would have really enjoyed learning more about what it’s like to have a career in astrophysics, but as it was written actually somewhat detracted from the larger point of the book.

I remember being about nine years old and sitting with the son of family friends, discussing if there was life in outer space somewhere. We were both sure there was. Sixty some years later, science has yet to pin down a definitive answer to the question, but I don’t expect to be visited by War of the World type Martians or the giant robot from The Day the Earth Stood Still. What can we expect? And would alien life be recognizable to us any more than we could recognize it?

Alien Earths shares Dr. Lisa Kaltenegger’s quest to discover life in the cosmos. She asks important questions. What is life? What is a habitable world? How does one look for life in the cosmos? She explains the concepts with illustrations geared to the non-scientist.

The author also addresses the difficult environment female scientists face their entire life, counselors and educators and peers entrenched in the belief that women are incapable of making a career in the natural sciences.

Descriptions of alien worlds and the mysteries of life and the universe spur the imagination. We are taken across the known universe as she imagines the environments of other planets.

“If someone has found us already,” she ends, considering how we have impacted our planet for the worse, “I wonder what they think of us.”

Thanks to the publisher for a free book.

I received a gifted copy of ALIEN EARTHS: THE NEW SCIENCE OF PLANET HUNTING IN THE COSMOS by Lisa Kaltenegger from St. Martin’s Press. I also received the audiobook from Macmillan Audio.

ALIEN EARTHS takes at the science and research that is going into the quest to find out if there is life out there in the cosmos. Given that we don’t have the technology to leave our solar system and explore the far reaches of space, science must find ways to bring answers into reach through alternate means.

Lisa Kaltenegger is an astrophysicist and a founding director of Cornell University’s Carl Sagan Institute. She talks about the ways we can use our own home planet and all that we know about it’s history and present to inform the search for other life in the universe.

This book cover immediately caught my eye. I really enjoy nonfiction that brings more information about the natural world and space is always a fascinating discussion. I think the author did a good job of explaining the science she was conveying in a way that made it approachable for the non-scientific minded. She promises an “insider’s guide” to what scientists are learning from Earth, its biosphere, and some of the discoveries that have already been made.

4.5 Stars

This was a really intresting accessible introductory look into the subject matter. I thought there was a good amount of balance to try and make relatable examples of some oof the science, with a few sprinkles of pop culture to try and appeal to the general reader. I really found some of the collaborative work interesting, and the approach to finding life elsewhere needing to start with taking a look at life on Earth in order to be able to recognize it. I also that that the author had a unique approach to sexism in the scientific field. In most places I wished it dived deeper, but I understand many readers might not be looking for that. If you love space books with a focus on finding life I would certainly pick this book up.

Thank you to the author, publisher, and NetGalley for an advanced copy in exchange for an honest review.

This book accomplishes something almost impossible in science publications, it makes everything understandable to all readers without dumbing things down. With a conversational style that makes it easy to follow, Doctor Kaltenegger brings vividly to life what we know, or imagine, of other stars and planets. When someone says how they’re looking for alien life, she is not what comes to mind: a serious professional who applies the most stringent scientific methods to this search. This is not little green men, it is the chemical composition of stars and atmospheres, the position of the planets (or moons) within their system and many other clues as to the possibility of life. It is fascinating. Along the way, she explains how we know what we know, and how this field has evolved along with technology (and a lot of trial and error). She also puts everything in perspective, including one of my favorite parts, where she establishes where and when our immediate neighbors could see us. The other part that I enjoyed enormously was her finding real planets similar to the fictional ones that we all know and love (though I don’t appreciate how she ruined Tatooine for me due to a missing shadow!). The book is realistic enough that it disappointed me a little (how will we ever join the Federation if almost no one knows we’re here?) But she is also optimistic in that we live in a system and maybe someday, hopefully, we’ll expand our universe beyond our own spaceship Earth.
I chose to read this book and all opinions in this review are my own and completely unbiased. Thank you, #NetGalley/#St. Martin's Press.

Lisa Kaltenegger gives us a fascinating and comprehensible look at space and the universe. This is a subject I have always been fascinated with since reading my Encyclopedias at our home library. There are so many new information now with new planets and advanced technology that Kaltnegger summarizes the timelines and origins. It is truly fascinating and really recommend this book to someone who wants a primer in this subject and one that insipre. I sure was.

This is an easy-to-read and a very interesting book.

Thank You to St. Martin’s Press and NetGalley for providing me with an advanced copy of this book with an expected release date of April 16, 2024.

"Alien Earths: The New Science of Planet Hunting in the Cosmos" by Dr. Lisa Kaltenegger is a captivating voyage through the cosmos, where science and wonder come together. In this riveting exploration, Kaltenegger takes readers beyond our pale blue dot and contemplate the possibility of life elsewhere in the universe.

The book's premise is both profound and timely: Are we alone? For millennia, humans have gazed at the stars, pondering this fundamental question. Now, armed with cutting-edge technology, we embark on a quest to uncover the secrets of distant worlds. Kaltenegger, as the founding director of Cornell University's Carl Sagan Institute, leads us on this cosmic odyssey.

The narrative unfolds like a celestial detective story. How do we detect life over cosmic distances? What constitutes life? These questions propel us into the heart of exoplanet research. Kaltenegger deftly explains the specialized toolkit her team has assembled; a Rosetta Stone forged from Earth's history, and biosphere. Our home-world becomes a guide, revealing clues that may unlock the mysteries of alien realms.

With infectious enthusiasm, Kaltenegger introduces us to the most peculiar exoplanets. Imagine planets cloaked in oceans of molten lava, lonely wanderers adrift in the cosmic sea, and binary sunsets casting their warm glow. These are the celestial canvases where life might thrive—or where we might glimpse extraterrestrial beings gazing back at us.

The book delves into the imagined worlds of science fiction, bridging the gap between speculation and scientific reality. As we explore these distant realms, we encounter not just new continents but entire planets orbiting distant stars. Kaltenegger's prose dances between the poetic and the empirical, making complex concepts accessible to readers of all backgrounds.

One of the book's strengths lies in its interdisciplinary approach. Kaltenegger's team comprises tenacious scientists from various fields including astronomy, biology, chemistry, and more. Their collaboration mirrors the cosmic dance of elements that shape planetary environments. We witness the birth of stars, the evolution of atmospheres, and the delicate balance required for life to flourish.

The James Webb Space Telescope, poised to launch, promises to revolutionize our understanding of exoplanets. Kaltenegger's pioneering work ensures that we live in an epoch of unprecedented exploration. As we peer through the telescope's lens, we glimpse distant worlds that are potential homes for life. Perhaps, just perhaps, aliens gaze back at us, pondering their own existence.

Kaltenegger's prose sparkles with wonder, mirroring the awe we feel when contemplating the vastness of the cosmos. She navigates complex scientific concepts with clarity, never losing sight of the human desire to connect with the universe. Her writing invites us to dream alongside astronomers, to imagine the unimaginable.

This book is an invitation to join the cosmic conversation. Kaltenegger's passion infuses every page, urging us to look up, to wonder, and to seek answers among the stars. She becomes our tour guide and is a beacon illuminating the cosmic expanse.

Readers will enjoy “Alien Earths: The New Science of Planet Hunting in the Cosmos,” as it’s a captivating blend of science, imagination, and hope. Whether you're an amateur stargazer or a seasoned astronomer, this book will leave you pondering the universe long after you've turned the final page.

Thank you to NetGalley and St. Martin's Press for a temporary e-ARC in exchange for my honest review.

At this point, I've read most of major astronomy books written for a popular audience in the past six years. This is one of the best, and definitely recommended as a general introduction to how to think about astrobiology. Dr. Kaltenegger does a really good job of integrated personal stories into her science without making it too off-topic or unwieldy. If you keep up with astrobiology, this won't teach you anything new, but if you're looking to get caught up with the current research, this is the perfect introduction.

Overall, I thoroughly enjoyed Alien Earths, rating it at 4 stars, rounded up from a personal rating of 3.75. The book addresses thought provoking questions about our planet's beginnings, and other alien stars and planets that could serve as future options for hosting life. She explains the elements needed (or thought to be needed) for life to thrive, introduces the Goldilocks Zone, and even provides some fun facts and anecdotes along the way. The subjects, astrophysics, and astrobiology are both dense, but Dr. Kaltenegger does a good job of using colloquial language to ensure the content is presented so all readers can enjoy. Overall, the book progresses in a logical manner, jumping from one topic to the next with the appropriate flow and transition. While reading I did catch several typos but assume that the editor and author will address those before the book is sent for print. I would recommend this book to a friend who enjoys the topics of space exploration.

Thank you to St. Martin’s Press and NetGalley for providing me with an advanced copy of this book with an expected release date of April 16, 2024.

This engaging, easy-to-read book explores the quest to discover life beyond Earth, fueled by modern technology. Using Earth as a Rosetta Stone, it draws insights from its rich history and diverse biosphere. From exoplanets challenging our preconceptions, to science fiction’s imagined realms, this book offers a fascinating journey into the cosmos and our evolving understanding of life’s potential elsewhere.

Thanks, NetGalley, for the ARC I received. This is my honest and voluntary review.

With her new book, Alien Earths, Lisa Kaltenegger has established herself as the legitimate successor to Carl Sagan. Alien Earths is the most readable astronomy book I’ve ever read. That’s a huge compliment, but it’s well deserved. Kaltenegger, Director of the Carl Sagan Institute to Search for Life in the Cosmos at Cornell University, has written a book that is scientifically informative, exciting, and personal. As a leading figure in the search for life on other planets, Kaltenegger has told the story of that search from both the perspective of the history and progress of the scientific approach to the issue and the perspective of her own entry into the field and her approach to addressing the problem. In the course of doing so, the reader learns something of the basic science involved, the discoveries that have been made so far, and is given a vivid description of our cosmos as we currently understand it. She inserts just enough personal anecdotes to make us feel as if she’s telling us a story, not just presenting us with facts.

For an amateur, I’m reasonably well-versed in astronomy and planet science, but Alien Earths taught me a lot that I didn’t know. I learned that many of the exoplanets orbiting other stars that were discovered early are gas giants, somewhat like Jupiter, circling their stars in near orbits, close enough to cause a detectable wobble in the star. I learned that some burnt out stars continue to have planets orbiting their cold husks. I learned that small tardigrades, water animals barely large enough to be seen with the naked eye can survive in space and remain dormant for a hundred years. An Israeli moon shot that crash-landed may have dumped thousands of tardigrades on the moon, and they may be living there in a dormant state right now.

I’m a science fiction writer and I consume as much space science as I’m able to understand. One of the best things I gained from reading Alien Earths was an appreciation of how Earth has changed over the four and a half billion years it has existed and how those changes might appear to an outside observer. We think of our planet as mostly covered in oceans and continents with green vegetation, but most of us forget that it has not always been that way. The green vegetation that colors our planet wasn’t here before 750 million years ago, and the additional oxygen it helped to produce wasn’t sufficient to sustain the lives of mammals like us until 650 million years ago. There was a time in Earth’s past when it would have appeared black to an extraterrestrial observer, even a time when, because of the presence of oxygen but no plant life, the surface of the planet would have appeared red, like that of Mars. What Kaltenegger realized is that in our search for other planets that might support life, we might observe some of them at a time in their history when they resembled Earth in its distant past. She worked on developing light-spectrum “signatures” of these early stages of our planet in order to try to spot exoplanets that might be in one of these stages—perhaps a future Earth.

Thinking that our own planet is only at one stage in its progression and that it may be that only at this stage is it able to support human life, and at the same time realizing that there are countless other planets that have already passed such a stage or will only arrive there sometime in the future, so the prospect of other life in the universe is a dynamic one, changing over time, provides a certain perspective. We humans occupy not just a tiny speck of territory in a vastly large universe, but also a tiny slice of time in a vastly long universe-wide saga. Our presence on the universal stage is almost infinitely small. It’s a sobering thought. It’s also awe-inspiring, and the author manages to convey her own sense of wonder and awe at the discoveries that lead to such a perspective throughout her book. There are hints that she sees humanity’s future as not being tied to our planet, and perhaps not being tied to such a small slice of time.

Alien Earths is not fiction, it is not even mostly speculation. It is primarily science but written with the spirit and flair of a novel. It accomplishes what the best novels accomplish and that is to affect the reader’s perspective on the world and their sense of self. It does so by showing us what we know about the nature of our planet and the universe in which it and we exist. For a science fiction writer such as myself, it is full of information that fuels the imagination. For any reader it is a thrilling introduction to the stars, planets, and the cosmos.

Casey Dorman, author of the Voyages of the Delphi science fiction series: Ezekiel’s Brain and Prime Directive