Alien Earths

by Lisa Kaltenegger

Penguin Press Alien Earths The Search for Life in the Cosmos ABISBOOK Penguin Press.

Genres: Science, Nonfiction

288 pages, Paperback

Published December 23, 2025

About the author

Lisa Kaltenegger is the Director of the Carl Sagan Institute to Search for Life in the Cosmos at Cornell and Associate Professor in Astronomy. She is a pioneer and world-leading expert in modeling potential habitable worlds and their detectable spectral fingerprint. Kaltenegger serves on the National Science Foundation's Astronomy and Astrophysics Advisory Committee (AAAC), and on NASA senior review of operating missions. She is a Science Team Member of NASA's TESS Mission as well as the NIRISS instrument on James Webb Space Telescope. Kaltenegger was named one of America’s Young Innovators by Smithsonian Magazine, an Innovator to Watch by TIME Magazine. She appears in the IMAX 3D movie "The Search for Life in Space" and speaks frequently, including at Aspen Ideas Festival, TED Youth, World Science Festival and the Kavli Foundation lecture at the Adler Planetarium which was live-streamed to six continents.

Reviews

[Doc of the Dark Arts · Rating 4 out of 5]

3.5/5 Stars
Format: Paperback
Spoilers: No

I read this after reading Project Hail Mary. PHM gave me an interest in jumping into some of the real science of it all. This was a very interesting look into the possibility of life in the rest of the known universe, and how we are searching for it. The scientific explanations were great - I have a strong science background, but I think the author did a great job making the explanations easy to understand for the layperson. It does get a bit autobiographical at times, and somewhat repetitive at points, but overall a great read if you're looking for some interesting real science of how a world like Project Hail Mary could exist.

[Olive · Rating 3 out of 5]

3.5

first half is stunning, lots of facts that are easy to comprehend

second half is much more biographical which is fine but not what I wanted

[Reader · Rating 2 out of 5]

I found this book disappointing. Drowning the genuinely interesting information was so much repetition, over- and under- explanation, (fair enough in a way as Lisa doesn't know most of her audience) pages and pages of personal anecdotes right down to describing children making sandcastles on the beach and Lisa's meetings with other scientists and where they enjoyed drinking coffee and why... Many sentences beginning with 'but' (my grammar isn't perfect, but I'm not trying to sell a book). I eventually got fed up with trying to pick and enjoy out the relevant parts and gave up 7/8 of the way through. I really wanted to like it. Probably 2 and a half stars because of the effort taken. It feels like a massive bundle of work notes, personal memoirs and astronomy factlets have been mixed together quite randomly.

[Ryan Shepard · Rating 4 out of 5]

Overall, a pretty easy read for those of us who are not in the field of astronomy. I felt like the beginning couple chapters and the last chapter had the most scientific fact information which I found interesting and the most educational. As a trained scientist, I thought bringing in her perspective on training/working in science was interesting, but kind of detracted from what I would consider the main point of the book. But maybe it is of use to young scholars considering going into that field to have the perspective. Not a bad read!

[Roisin Walsh · Rating 4 out of 5]

This was wonderfully easy to read despite covering a lot of 'big' topics. I enjoyed the personal, humane touch Kaltenegger brings to her scientific writing.
My main takeaway from this book, however, is that we as a society need to instigate a ban on scientists coming up with quirky little acronyms for their projects. The linguistic and mental backflips they are expecting us to do to make these names fit the acronyms are frankly ridiculous.
TRAPPIST? SPECULOOS?
You're taking the piss.

[theo vengan · Rating 2 out of 5]

‘It is detective work. How do you catch thieves? By looking for the fingerprints they leave behind. Life has its own fingerprints.’

[Tanith Pyner · Rating 4 out of 5]

"Makes you feel so, sort of, insignificant, doesn't it?"