Whether life exists anywhere other than Earth is a burning question that has long, and may soon, be answered.
The clues we see on exoplanets can be as strange as a bioluminescent glow or a rainbow hue to an astronomer. Lisa Kaldenecker He explains in his accessible new book, „Alien Earths: The New Science of Planet Hunting in the Cosmos.”
Director Carl Sagan Company (CSI) and associate professor of astronomy in the College of Arts and Sciences, Kaldenegger has been searching for life on other worlds for decades. In „Alien Earths,” out April 16, he chronicles his personal and professional journey and asks, „What is life?” He describes the journey of other pioneers as they find answers to the big questions, including a chapter on – and how can it be recognized if it cannot be defined?
This book is featured Important note about eCornell Stakes in Chats event on April 16 at 2 pm and April 18 at 4:30 pm, in person 160 in the Mann Library or Online via Zoom.
Kaldenegger spoke with the Chronicle about his book:
Q: You share a good part of your personal story in the book, interwoven with science, including being on the ground floor of exoplanet research. What do you find most compelling about the search for life in the universe?
Answer: The first planet orbiting another star similar to our Sun was discovered when I was in college. It was interesting, but I didn't think I could be a part of it because I'm from a very small town in Austria, a small country. And I don't see anyone who looks like me as a woman doing this. But three years after the discovery, I attended one of the first small conferences on the topic. There are not many people, and the lively discussions among scientists, professors and students about these obvious questions show that no one has an answer yet. „We need people to answer these questions – what do you think?” I remember several professors saying that. Suddenly, I was part of a conversation about these new worlds. It was the first time I had the idea that I could be a part of this search, that I could help find out if we were alone in the universe. It changed my worldview: I came back from that conference realizing that no one had the answers to these questions, and that everyone, including me, could be a part of it. And this is how I got into the field.
Q: You've covered a huge range of scientific discoveries, from the question of how to define life to the dramatic variation in planetary surfaces from lava to ocean worlds. What do you see as the most important goal as we hunt for life-bearing planets?
A: We need to find its planet-changing biosphere. This is why I created a network of researchers from different disciplines here at Cornell: the Carl Sagan Institute, which I founded almost 10 years ago. To succeed in identifying signs of life on other worlds, we need to combine ideas from different fields. For example, my research group focuses on modeling how to find signs of life in the air or on the surface of planets such as Earth under different conditions, such as under red sunlight or on worlds surrounded by oceans. But to do that, the diversity of life is another important puzzle piece we need to add—like how different colors might reveal biota on other worlds. So thanks to inspiring collaborations at CSI with colleagues in the microbiology and civil engineering departments at Cornell and colleagues around the world, I created a color table that captures more and more forms of life. If there's a mixture of gases in the planet's air, I can only explain it with life, but I've also seen biopigments that make life – completely different evidence – and the two together make a very strong case for life on another world.
These are two pieces of the larger puzzle of how to find life in the universe. No single man can know all science anymore; Fortunately there is much to learn now. CSI has successfully connected thinkers across Cornell to tackle these questions together. It is exciting to see the Carl Sagan Institute at Cornell continue to grow and carry Carl Sagan's legacy into the future.
Q: Through your descriptions of Earth's evolution, you imply that in order to understand other worlds we must first understand our own, and vice versa. What have we learned from the study of other worlds that is important to understanding our world?
A: We don't have much data yet, but for the first time it's possible to explore other rocky worlds with the James Webb Space Telescope – from lava worlds where the rocks on the surface are melted and covered by volcanic oceans. To worlds like ours. Studying other alien Earths, some older and some younger than ours, will give us important insights into how Earth works and what processes shape a planet like ours at different stages of its evolution. It may even provide a glimpse into our possible future. Such insights may help us solve problems on our own planet before they become acute.
Linda B. Glaser is the News and Media Relations Manager for the College of Arts and Sciences.