Mars’ Ancient Carbon Cycle: How Rocks on Mars Tell the Story of a Vanishing Climate
Join planetary scientist Beth Johnson as we explore a groundbreaking discovery from NASA's Curiosity rover on Mars. Scientists have identified siderite—a rare iron carbonate mineral—within ancient Martian rocks, offering new insights into Mars' once-thicker atmosphere and its now-lost carbon cycle. This discovery reshapes our understanding of the Red Planet's climate history and helps us draw powerful parallels to Earth's carbon processes. Dr. Ben Tutolo, associate professor at the University of Calgary and participating scientist on NASA's Curiosity rover team, explains that as Mars' atmosphere thinned over time, carbon dioxide was sequestered into rock formations, leading to a dramatic climate shift from a warm, wet environment to the cold, arid planet we see today. These findings provide evidence that ancient Mars was habitable and offer insights into the fragility of planetary climates. Dr. Tutolo emphasizes the parallels between Mars' atmospheric changes and current efforts on Earth to mitigate climate change by converting anthropogenic CO₂ into stable carbonates. Understanding the mechanisms of carbon sequestration on Mars could inform strategies to address climate challenges on our own planet. (Recorded live 5 June 2025.)
--------
32:31
Titan’s Missing Deltas? What Cassini Saw — and What It Didn’t
Why are Titan’s river deltas missing? Planetary astronomer Franck Marchis taps in for Beth Johnson to chat with Brown University’s Sam Birch and explore a strange and unexpected mystery on Saturn’s largest moon. Using data from NASA’s Cassini mission and advanced computer modeling, Birch’s team reveals that Titan's shorelines defy Earth-like expectations. Despite Titan's known rivers and seas of liquid methane, the team found a surprising absence of deltas—landforms typically formed when rivers deposit sediment at their mouths. This finding challenges existing geological expectations, as deltas are common on Earth where rivers meet larger bodies of water, and suggests that Titan's geological and climatic processes differ significantly. This discovery opens new avenues for research into Titan's sediment transport mechanisms and its potential to preserve signs of past environmental conditions or even life. (Recorded live 29 May 2025.)
--------
28:12
A Cookbook of Life: How Chemistry Might Explain Life on Other Planets
What if the origin of life isn’t a one-in-a-billion cosmic fluke, but something that happens whenever the conditions are just right? Join communications specialist Beth Johnson as we explore groundbreaking research from the University of Wisconsin–Madison, where scientists have identified over 270 self-replicating chemical reactions that may have sparked life, not just on Earth, but potentially anywhere in the universe. Led by astrobiologist Dr. Betül Kaçar, this study reframes our understanding of how life can emerge from simple chemistry. Discover how these "chemical recipes" might reveal a universal pattern for life, help us search distant planets more effectively, and bring us one step closer to answering one of humanity’s biggest questions: Are we alone? (Recorded live 15 May 2025.)
--------
29:39
Red Planet, Blue Past: How Rain Shaped the Martian Landscape
A groundbreaking study from the University of Colorado Boulder suggests that ancient Mars was far from the cold, arid planet we know today. Led by Amanda Steckel, the research team utilized computer simulations to reveal that billions of years ago, Mars experienced significant precipitation—either rain or snow—that carved out extensive networks of valleys and channels across its surface. These findings challenge previous theories that Mars was predominantly cold and dry, instead supporting the idea of a warmer, wetter climate during the Noachian epoch, approximately 4.1 to 3.7 billion years ago. The study provides compelling evidence that precipitation played a crucial role in shaping the Martian landscape, offering new insights into the planet's climatic history and its potential to have supported life. Join planetary scientist Beth Johnson and Dr. Steckel as they discuss the results of this study and its implications for finding life, especially past life, on Mars. (Recorded live 8 May 2025.)
--------
33:21
Tiny Asteroids, Big Threats: JWST Reveals a Hidden World of Mini Asteroids
One significant threat to life here on Earth is the possibility that a massive asteroid will collide with our planet and destroy life as we know it. To understand the possibilities, large surveys of the sky have found around 95% of potentially hazardous asteroids larger than a kilometer. Smaller asteroids, however, can also cause massive amounts of damage. Estimates range from 40 to 60 percent when it comes to asteroids over 100 meters in diameter, which would be considered city-killers. Even smaller asteroids, such as the 20-meter one that exploded over Chelyabinsk in 2013, can cause destruction and injury. The more asteroids we can find, the better our predictions and future protections will be. In light of this threat, scientists have used the JWST to detect 138 of the smallest asteroids (as small as 10 meters) ever observed in the asteroid belt. These tiny asteroids are important because they can become near-Earth objects (NEOs), posing a risk to Earth through possible impacts, including powerful explosions. By analyzing the size and frequency of asteroids, researchers found a significant change in the population of asteroids around 100 meters in size, likely due to collisions breaking larger asteroids into smaller ones. The observed asteroids originated from known asteroid families and were detected using advanced tracking and infrared imaging techniques. This research enhances our understanding of asteroid behavior and may aid in predicting and mitigating future asteroid threats. Join planetary astronomer Franck Marchis in a conversation with lead authors Artem Y. Burdanov and Julien de Wit as they discuss these smaller asteroids and what they can reveal about potential threats to our planet. (Recorded live 1 May 2025.)
SETI Live is a weekly production of the SETI Institute and is recorded live on stream with viewers on YouTube, Facebook, LinkedIn, X (formerly known as Twitter), and Twitch. Guests include astronomers, planetary scientists, cosmologists, and more, working on current scientific research. Founded in 1984, the SETI Institute is a non-profit, multi-disciplinary research and education organization whose mission is to lead humanity’s quest to understand the origins and prevalence of life and intelligence in the Universe and to share that knowledge with the world.
Ireland