SETI Live

What happens when a visitor from another star system drops by? Join planetary astronomers Franck Marchis and Ariel Graykowski for a special SETI Live all about Comet 3I/ATLAS — only the third known interstellar object ever detected! Astronomers around the world, including citizen scientists in the Unistellar Network, are racing to learn as much as possible about this rare cosmic traveler. 3I/ATLAS is swinging through our neighborhood, reaching perihelion on October 30, 2025, just inside the orbit of Mars — a front-row seat for spacecraft like Lucy and Psyche. While it's currently hidden behind the Sun, it won't stay that way for long. By December 2025, 3I/ATLAS will reappear, ready for a fresh round of observations from Earth and its Lagrange-point observatories. We'll dive into what scientists have discovered so far, how they're studying this interstellar visitor, and what it might reveal about the chemistry and dynamics of other star systems. Don't miss it — interstellar comets don't come around every day! (Recorded live 31 October 2025.)

Join host Beth Johnson on SETI Live as she talks with Dr. Eric Boyd from the University of Montana about a groundbreaking discovery: microbes that can breathe in two ways at once! These extraordinary bacteria simultaneously perform both aerobic (oxygen-based) and anaerobic (sulfur-based) respiration, challenging everything we thought we knew about cellular life. Discover how this incredible metabolic flexibility reshapes our understanding of life on Earth, inspires biotechnology innovations, and even informs the search for extraterrestrial life. 🔬 Featured Research: Quanta Magazine overview: https://www.quantamagazine.org/the-cells-that-breathe-two-ways-20250723/ Original study: https://www.nature.com/articles/s41467-025-56418-4 Dr. Boyd's website: http://geoboydology.com/ 💡 Learn how microbes survive extreme environments and why this discovery matters for science and space exploration. (Recorded live 30 October 2025.)

Could Uranus's moon Ariel have once harbored a vast, deep ocean beneath its icy crust—perhaps even one that still lingers today? In this episode of SETI Live, host Beth Johnson welcomes Caleb Strom (University of North Dakota) and Alex Pathoff (Planetary Science Institute) to discuss new research revealing evidence that Ariel may have once held a subsurface ocean over 170 kilometers deep. Using geological mapping and tidal‐stress modeling, the team shows how ancient fractures and ridges on Ariel's surface hint at powerful internal forces and a dynamic, watery past. This discovery expands the growing family of "ocean worlds"—planets and moons that may have once supported (or could still support) conditions for life. What does this mean for future exploration of the Uranus system, and what could we learn by going there? 🔗 Press release: https://www.psi.edu/blog/evidence-of-a-past-deep-ocean-on-uranian-moon-ariel/ 📄 Paper: https://www.sciencedirect.com/science/article/abs/pii/S0019103525003707 (Recorded live 23 October 2025.)

Join Beth Johnson for a thought-provoking conversation with Professor Dagomar Degroot, an environmental historian at Georgetown University. They delve into the themes of his new book, Ripples on the Cosmic Ocean, set to be released on October 28, 2025. Ripples on the Cosmic Ocean offers a sweeping history of human encounters with the solar system. Professor Degroot reimagines the solar system as a dynamic network of interconnected systems, exploring how cosmic events and environments have influenced human history and understanding. Drawing inspiration from James Lovelock's Gaia hypothesis, he treats the entire solar system as a network of interconnected systems of exchange and influence, all of which shape even the most innocuous facts of life on Earth. 📘 Order the book: https://www.hup.harvard.edu/books/9780674986503 (Recorded live 28 October 20250.)

Do Aliens Speak Physics?: And Other Questions about Science and the Nature of Reality (Whiteson & Warner, 2025) is a mind-bending exploration into what it would mean, scientifically and philosophically, for humans to communicate with an extraterrestrial intelligence through the language of physics. Daniel Whiteson, a particle physicist, and Andy Warner tackle deep questions: Are concepts like "number," "space," "time," and "laws of nature" universal, or are they shaped by our biology, culture, and perception? What assumptions do we make that might not translate to a species evolved under utterly different conditions? The book pushes us to examine where physics ends and human perspective begins, to reflect on whether alien minds might think mathematics differently, sense reality differently, or have radically different "basic science." Join us on SETI Live as communications specialist Beth Johnson speaks with co-author Daniel Whiteson about the surprising places he found ambiguity, what assumptions underlie science as we know it, and what our notion of physics might reveal — or blind us to — when grappling with alien intelligence. Learn more about the book: https://sites.uci.edu/alienphysics/ (Recorded live 16 October 2025.)

How do planets start? Host Simon Steel (SETI Institute) speaks with Melissa McClure (Leiden University), lead author of a new study that caught the earliest spark of planet formation. Using JWST and ALMA, the team detected silicon monoxide (SiO)—both gaseous and likely crystalline—and pinpointed where hot, rock-forming minerals are condensing inside the protoplanetary disk of HOPS-315, ~1300 light-years away in Orion. They also map the action to a belt-like region similar to our Solar System's asteroid belt. What does SiO reveal about shocks, heat, and the first solids that seed planets? Join us to unpack the chemistry, the physics, and the cosmic "baby book" of a solar system in the making. ESO press release: https://www.eso.org/public/unitedkingdom/news/eso2512/ Nature paper: https://www.nature.com/articles/s41586-025-09163-z (Recorded live 9 October 2025.)

The Sun is restless again! A massive coronal hole has opened up, sending streams of solar wind racing toward Earth. These high-speed particles not only light up our skies with dazzling auroras but can also affect satellites, power grids, and communications. In this special SETI Live, heliophysicist Dr. Becca Robinson (SETI Institute) joins host Simon Steel (Deputy Director of the Carl Sagan Center at the SETI Institute) to explain what coronal holes are, how they form, and what their impacts mean for both our technology and our understanding of the Sun. Join us on October 7 at 2:30 pm PT for a deep dive into the science of solar storms, space weather, and the mysteries of our nearest star. Aurora videos courtesy of Vincent Ledvina, The Aurora Guy, https://theauroraguy.com/ Participate in citizen science at https://aurorasaurus.org/ Learn more about the MUSE mission: https://muse.lmsal.com/ (Recorded live 7 October 2025.)

Join host Beth Johnson and guest Dr. Sam Courville, lead author of a new study on Ceres, as they dive into the possibility that the dwarf planet may have had the energy needed to support habitability for much longer than once believed. Using data from NASA's Dawn mission, researchers uncovered evidence of persistent geologic activity, brine movement, and long-lived energy sources beneath Ceres' icy surface. Could this small world in the asteroid belt have been more habitable than we ever imagined? Press release: https://www.jpl.nasa.gov/news/nasa-ceres-may-have-had-long-standing-energy-to-fuel-habitability/ Paper: https://www.science.org/doi/10.1126/sciadv.adt3283 (Recorded live 2 October 2025.)

Join host Dr. Franck Marchis and guest Dr. Andy Rivkin (Johns Hopkins University Applied Physics Laboratory) for a discussion on asteroid 2024 YR4 and its potential impact on the Moon. Thanks to new observations with the James Webb Space Telescope (JWST), scientists have refined the asteroid's orbit and determined there is about a 4% chance it could strike the Moon in December 2032. While there is no risk to Earth, a lunar impact could create a crater nearly a kilometer wide and send debris into space—possibly affecting satellites or even producing a visible meteor shower. In this episode, we'll explore how JWST contributed to narrowing the odds, what such an impact would mean for lunar science, and how planetary defense research helps us better understand and prepare for near-Earth objects. NASA Blog: https://science.nasa.gov/blogs/planetary-defense/2025/06/05/nasas-webb-observations-update-asteroid-2024-yr4s-lunar-impact-odds/ (Recorded live 25 September 2025.)

What happens after we discover life beyond Earth? The question is no longer "if," but "when"—and how humanity responds could shape our future. Host and planetary astronomer Franck Marchis welcomes Martin Dominik, one of the authors of a new white paper on the societal, political, and philosophical challenges we'll face once alien life is confirmed. From public communication and policy to our collective sense of identity, this discussion explores how to prepare for the biggest discovery in human history. 📄 Read the paper: https://arxiv.org/abs/2507.11587 📰 Universe Today article: https://www.universetoday.com/articles/scientists-are-planning-for-life-after-finding-aliens (Recorded 18 September 2025.)