Alien Earths

Alien Earths

Planet Hunting in the Cosmos


‘Lisa Kaltenegger offers first-hand access to her expertise on the search for planets in the universe, and the life they may contain. Along the way, Lisa's breezy narrative style invites you to experience with her the challenges and joys of being a scientist on the frontier of discovery’ Neil deGrasse Tyson, Astrophysicist

For thousands of years, humans have wondered whether we're alone in the cosmos. Now, for the first time, we have the technology to investigate. The question should have an obvious answer: yes or no. But once you try to find life elsewhere, you realize it is not so simple. How do you find it over cosmic distances? What actually is life?

Astronomer Lisa Kaltenegger works from Carl Sagan’s former office at Cornell University, where she built a team of tenacious scientists from many disciplines to find life on faraway worlds, using Earth’s diverse biosphere and its history as a Rosetta Stone. With infectious enthusiasm, she provides an eye-opening insider’s guide to the most unusual exoplanets that have shaken our worldview – planets covered in oceans of lava, lonely wanderers lost in space, and others with more than one sun in their sky – as well as the best contenders for Alien Earths. She also shows how close imagined scifi worlds come to reality.

We live in an incredible new epoch of exploration. As our witty and knowledgeable tour guide, Professor Kaltenegger shows how we discover not merely new continents, like the explorers of old, but whole new worlds circling other stars – and how we could spot life there. Worlds from where aliens may even be gazing back at us. What if we're not alone?


  • Lisa Kaltenegger is an enthusiastic guide to the search for life beyond our planet — and the new technologies that could help it succeed ... [the] director of Cornell’s Carl Sagan Institute, stands out from the crowd of authors as one of the world’s leading practitioners of astrobiology, with extensive personal involvement in the field. She writes with exemplary clarity about the remarkable diversity of the thousands of planets already identified beyond our solar system — and explains how we could detect clear signs of biology in outer space from the vast influx of data provided by a new generation of ultra-powerful telescopes over the next few years ... the tone of Alien Earths is overwhelmingly positive, as Kaltenegger rejoices in her “adventure to find life in the cosmos” and invites readers to share her excitement for the search, without getting carried away by “wild claims” with insufficient evidence ... she writes.“The most exciting phase is about to begin.”
    Clive Cookson, Financial Times

About the author

Lisa Kaltenegger

Lisa Kaltenegger is the Director of the Carl Sagan Institute to Search for Life in the Cosmos at Cornell University, and Associate Professor in Astronomy. She is a pioneer and world-leading expert in modeling potential habitable worlds and their detectable spectral fingerprint. Professor Kaltenegger has served on NSF and NASA committees and is a Science Team Member of NASA's TESS Mission as well as the NIRISS instrument on the James Webb Space Telescope.

Professor Kaltenegger is the recipient of numerous international prizes and awards, including being a European Commission Role Model for Women in Science and Research. She was named one of America's Young Innovators by Smithsonian Magazine, an Innovator to Watch by TIME Magazine, and stars in the IMAX 3D movie "The Search for Life in Space". Asteroid Kaltenegger7734 is named after her.
Learn More

Sign up to the Penguin Newsletter

For the latest books, recommendations, author interviews and more