Are we alone in the universe? We're close to finding out | Lisa Kaltenegger

Summary

Podcast Summary: "Are We Alone in the Universe? We're Close to Finding Out" | Lisa Kaltenegger

Podcast: TED Talks Daily
Host: Elise Hu
Speaker: Lisa Kaltenegger
Release Date: January 28, 2025

Introduction

In this compelling episode of TED Talks Daily, host Elise Hu introduces Lisa Kaltenegger, an esteemed Alien World explorer and founder of the Carl Sagan Institute at Cornell University. Kaltenegger delves into one of humanity's most profound questions: Are we alone in the universe? Drawing from her 2024 TED Talk, she explores the latest advancements in astronomy and the tools that bring us closer to answering this age-old inquiry.

The Quest for Extraterrestrial Life

Lisa Kaltenegger opens by emphasizing the unprecedented era of exploration we are currently experiencing:

"We live in an incredible time of exploration, on the verge of finding out whether we are alone in the cosmos or not. This is one of the biggest questions humankind has ever asked." [03:15]

She highlights the transformative role of the James Webb Space Telescope (JWST) in this quest. Unlike its predecessors, the JWST possesses the sensitivity to detect light from Earth-like planets orbiting distant stars, facilitating the search for signs of life beyond our solar system.

Understanding Cosmic Distances and Light

Kaltenegger elucidates the concept of light travel time and its implications for our observations:

"When you look up at the sky at night, you look back in time." [04:20]

She explains that light from distant stars takes years to reach us, meaning we observe celestial objects as they were in the past. This temporal distance underscores the challenges in detecting current life forms elsewhere.

Light Fingerprints: Detecting Life Through Spectroscopy

A central theme of Kaltenegger's discussion is the use of spectroscopy to identify potential life:

"Light carries energy, and if it hits a molecule with just the right energy, that molecule would start to swing and rotate. So it's really the missing light, the light that doesn't make it to my telescope, that tells me which molecules the light encountered before it got to me." [05:30]

By analyzing the absorption lines in a planet's atmospheric spectrum, scientists can infer the presence of specific molecules. The combination of oxygen and methane serves as a potential biosignature for carbon-based life on planets within the habitable zone of their stars.

Our Cosmic Connection

Kaltenegger beautifully connects humanity to the cosmos, emphasizing our shared origins:

"You and me, all of us, are made of ancient stardust because it took the heat in the core of a star and the violent explosion at the end of its lifetime to make the atoms that made you and me." [07:45]

This profound realization fosters a sense of unity and highlights the interconnectedness of life in the universe.

Diverse Possibilities of Life Forms

Challenging our Earth-centric perspective, Kaltenegger envisions diverse forms of life that could exist under different planetary conditions:

"There could be planets completely covered in oceans with waves that never break on a shore. Or planets half in eternal sunlight and half in perpetual night. Or planets that are covered with a purple landscape because purple bacteria is very sturdy, it can thrive under red sunlight." [09:10]

She points out that purple might become the new green when searching for life, especially around red stars, which constitute 80% of stars in our galaxy.

The Carl Sagan Institute and Future Endeavors

As the founder of the Carl Sagan Institute, Kaltenegger underscores the collaborative efforts to advance the search for extraterrestrial life:

"We created a spectral database, a light fingerprint database for habitable worlds." [10:05]

This innovative database serves as a critical tool for cataloging and analyzing the atmospheric compositions of exoplanets, enhancing our ability to identify promising candidates for life.

Optimism for the Future

Kaltenegger conveys an optimistic outlook on the future of space exploration:

"The cosmos is 13.8 billion years old. But we all get to live in the most exciting time where the search for life on other planets went from impossible to possible." [11:50]

She emphasizes that with ongoing technological advancements and larger telescopes in development, our capabilities to detect and analyze distant worlds are expanding rapidly.

Inspiring Curiosity and Wonder

Concluding her talk, Kaltenegger encourages listeners to embrace the wonder of the cosmos:

"Find your favorite star and allow yourself to wonder, what if? We're not alone." [12:30]

Her heartfelt message serves as a reminder of the endless possibilities that the universe holds and the pivotal role human curiosity plays in unraveling its mysteries.

Conclusion

Lisa Kaltenegger's insightful presentation bridges the realms of astronomy, biology, and philosophy, offering a comprehensive overview of humanity's quest to discover life beyond Earth. By leveraging cutting-edge technology and fostering interdisciplinary collaboration, we stand on the cusp of potentially transformative discoveries that could redefine our understanding of life in the universe.

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For those intrigued by the endless possibilities of the cosmos and the scientific endeavors to uncover extraterrestrial life, this episode of TED Talks Daily provides both inspiration and a deep dive into the methodologies driving this exciting frontier.

Transcript

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[Elise Hu]

You're listening to TED Talks Daily where we bring you new ideas to spark Your curiosity every day. I'm your host, Elise Hu. So many mysteries remain about the cosmos. Different solar systems, different planets, and what other life is out there. In her 2024 talk, Alien World explorer Lisa Kalteneg explains how the latest tools reveal truths not only about planets very far away, but also about who we are and how we're all connected. Enjoy.

[Lisa Kaltenegger]

We live in an incredible time of exploration, on the verge of finding out whether we alone in the cosmos or not. This is one of the biggest question humankind has ever asked. And now, for the first time, we have a tool that could find out. Because the James Webb Space Telescope is a telescope large enough to be able to catch light from planets like ours, as small as ours, but circling other stars light years away. Because this search is a search over vast cosmic distances, Even light needs years to travel these trillions of miles between stars. So when you look up at the sky at night, you look back in time. Let's imagine you on a planet circling our neighboring star about five, four light years away. Then you would see the Earth tonight like it was four years ago on a planet 70 million light years away. You could still see the dinosaurs roam here. And it also means that out in the sky, there is a star whose light arrives tonight that was sent out when you were born. Your personal connection to the cosmos. So these distances are vast, but astronomers throughout time have managed to unravel and reveal mysteries of the cosmos because light and matter interact. So light carries energy, and if it hits a molecule with just the right energy, that molecule would start to swing and rotate. So it's really the missing light, the light that doesn't make it to my telescope. That tells me which molecules the light encountered before it got to me. It's a little bit like a passport stamp that tells you where traveler was before arriving here. So when you look at this incredible image of the pillars of creation taken by the James Webb Space Telescope, it is gorgeous. But if you analyze the light, you realize that we are watching a stellar nursery where we see stars emerge and ignite. And when you look at stars on our night sky, you reveal another astonishing truth. That you and me, all of us, are made of ancient stardust because it took the heat in the core of a star and the violent explosion at the end of its lifetime to make the atoms that made you and me. So on a fundamental level, we are connected to each other and to the cosmos around us. And now, for the first time, we get to search for other organisms somewhere else that might be made of ancient stardust too. But when you try to find life in the universe, it is incredibly hard because planets are so much smaller and they're close to their bright and big stars. And we don't only want to find planets like ours, we want to look in the air and on their surface for signs of life. So what we do is we wait until the planet crosses our line of sight to its star and the light from its star hits smashes into the atmosphere of the planet before it gets to my telescope so I can look for these passport stamps to figure out what's in the air of planets very far away. And the light fingerprint. The best light fingerprint we have for life on the Earth is the combination of oxygen and methane for carbon based life with a water solvent on a planet in the temperate zone around its star. But I was really curious, how long could this light fingerprint actually tell you that there's life on our planet? And so I figured out that for about 2 billion years, the biosphere has painted signs of life into our atmosphere. So for half of Earth's existence, you could tell that there is life on our planet. And if life does this somewhere else too, for the first time, we have now a chance to spot it. And so searching for life in the universe actually made me see our planet completely differently. And it lets you start to think about how different these other planets could be. Like, there could be planets completely covered in oceans with waves that never break on a shore. Or planets half in eternal sunlight and half in perpetual night. Or planets that are covered with a purple landscape. Because purple bacteria is very sturdy, it can thrive under red sunlight. So 8 out of 10 stars out there are actually small red stars. So purple might be the new green when searching for life in the cosmos. But we know that one out of five sun like stars has a planet that could potentially be like ours. So with 200 billion stars in our Milky Way alone, that means we have billions and billions of possibilities. I founded the Carl Sagan Institute at Cornell to bring thinkers and creative minds from many different fields and backgrounds and ways of life to create the toolkit to find life in the cosmos. And so we created a spectral database, a light fingerprint database for habitable worlds. And in case you're wondering, actually, Jurassic worlds where space dinosaurs might roam somewhere else, are actually easier to find than a modern Earth because there was more oxygen when the dinosaurs lived here. I'm not saying they are space dinosaurs, but I'm just saying if you ever wanted there to be, I'm giving you options. But when you search, then one of the questions that came was also if there's life in the cosmos. Of course, I don't know that yet, but if there's life in the cosmos, could somebody looking at us with just the same technology we have. And there's a space on the sky, a strip where you have just the right vantage point to see the Earth go in front of the sun. And it encapsulates about 1,000 stars within 300 light years. What's really our cosmic background? And so the question is, where could we be the aliens? Is there life in the cosmos? I don't know. We don't know yet. But I really want to find out because the cosmos is 13.8 billion years old. But we all get to live in the most exciting time where the search for life on other planets went from impossible to possible. And it's at the edge of technical capability. But we are already designing larger telescopes that could catch more light of these planets to find out if there's life out there. Calling another planet home from a tiny town in Austria. When I looked up at the stars and wondered if they could be suns to their planets to now, sitting in Carl Sagan's old office at Cornell, the journey has been challenging, inspiring and full of wonder. Because those thousands of new stars, new suns on the sky, hold a breathtaking promise that our adventure of exploration has just begun. So go out at night and find your favorite star and allow yourself to wonder, what if? We're not alone. Thank you.

[Elise Hu]

That was Lisa kaltenagger@ted next 2024. If you're curious about Ted's curation, find out [e-mail] curationguidelines and that's it for today. TED Talks Daily is part of the TED Audio Collective. This episode was produced and edited by our team, Martha Estefanos, Oliver Friedman, Brian Greene, Autumn Thompson and Alejandra Salazar. It was mixed. Christopher Faizy Bogan. Additional support from Emma Topner and Daniela Ballarazo. I'm Elise Hu. I'll be back tomorrow with a fresh idea for your feet. Thanks for listening.

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