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For thousands of years, humans have wondered whether we\u2019re alone in the cosmos. Now, for the first time, we have the technology to investigate. But once you look for life elsewhere, you realize it is not so simple. How do you find it over cosmic distances? What actually is life?

As founding director of Cornell University\u2019s Carl Sagan Institute, astrophysicist Lisa Kaltenegger has built a team of tenacious scientists from many disciplines to create a specialized toolkit to find life on faraway worlds. In Alien Earths, she demonstrates how we can use our homeworld as a Rosetta Stone, creatively analyzing Earth\u2019s history and its astonishing biosphere to inform this search. With infectious enthusiasm, she takes us on an eye-opening journey 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! And the best contenders for Alien Earths. We also see the imagined worlds of science fiction and how close they come to reality.

With the James Webb Space Telescope and Dr. Kaltenegger\u2019s pioneering work, she shows that we live in an incredible new epoch of exploration. As our witty and knowledgeable tour guide, Dr. 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\u2019re not alone?

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\u2019s Astronomy and Astrophysics Advisory Committee (AAAC), and on NASA senior review of operating missions. She is a Science Team Member of NASA\u2019s TESS Mission as well as the NIRISS instrument on James Webb Space Telescope. Kaltenegger was named one of America\u2019s Young Innovators by Smithsonian magazine, an Innovator to Watch by Time magazine. She appears in the IMAX 3D movie \u201cThe Search for Life in Space\u201d and speaks frequently, including at Aspen Ideas Festival, TED Youth, World Science Festival and the Kavli Foundation lecture at the Adler Planetarium.

Shermer and Kaltenegger discuss: Carl Sagan and his influence \u2022 Sagan\u2019s Dragon \u2022 ECREE Principle \u2022 how stars, planets and solar systems form \u2022 how exoplanets are discovered \u2022 Hubble Space Telescope, Kepler Space Telescope, James Webb Space Telescope \u2022 The Origin of Life \u2022 Fermi\u2019s Paradox: where is everybody (the Great Silence, the Great Filter) \u2022 biosignatures \u2022 technosignatures \u2022 Dyson spheres \u2022 Will aliens be biological or AI? \u2022 interstellar travel \u2022 Kardashev scale of civilizations \u2022 how to talk to aliens when we can\u2019t even talk to dolphins \u2022 Deities for Atheists, Skygods for Skeptics: aliens as gods and the search as religion \u2022 why alien worlds matter.