Planetary Radio: Space Exploration, Astronomy and Science

Could a single ancient impact have briefly transformed one of the Solar System’s darkest moons into a cryovolcanic world?
When Voyager 2 flew past Uranus in 1986, it captured the only close-up images we have of Umbriel, a heavily cratered, charcoal-dark satellite long considered geologically inactive. But one feature stands out: a bright ring inside the 131-kilometer-wide Wunda crater.
In this episode, Sarah Al-Ahmed speaks with Adeene Denton, NASA postdoctoral program fellow at the Southwest Research Institute, about her team’s new study published in the Journal of Geophysical Research: Planets. Using shock physics simulations, Denton and her colleagues reconstruct the impact that formed Wunda crater to determine what Umbriel’s interior must have been like at the time. Their modeling explores whether impact-induced cryovolcanism can explain the bright deposits observed on the crater floor.
Then, in What’s Up, Bruce Betts, chief scientist of The Planetary Society, joins Sarah to break down one of the key mechanisms that keeps icy moons from freezing solid, tidal heating driven by orbital resonance.
Discover more at: https://www.planetary.org/planetary-radio/2026-cryovolcanism-on-umbriel
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They informed and entertained together throughout the first 20 years of Planetary Radio. Listen in as the Society’s chief scientist and book club edition host Mat Kaplan share the mic once again for a delightful conversation about Dr. Betts’ two new space books for young people. “Are We Alone?” introduces the search for life across the Universe, while “The Size of Space” collects many of Bruce’s brilliant and hilarious ways to cut our Solar System down to human size.

Discover more at: https://www.planetary.org/planetary-radio/book-club-bruce-betts
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This week on Planetary Radio, we mark a major leadership transition at The Planetary Society. Host Sarah Al-Ahmed sits down with Bill Nye, outgoing chief executive officer and newly appointed chief ambassador of The Planetary Society, and Jennifer Vaughn, incoming chief executive officer and former chief operating officer, for a candid conversation about this long-planned transition. Together, Bill and Jenn reflect on how the organization, under their shared leadership, grew into the world’s largest and most effective nonprofit dedicated to advancing the scientific exploration of space.
Then, Bruce Betts, chief scientist of The Planetary Society, joins Sarah for What’s Up. They discuss an upcoming planetary alignment on and around February 28, 2026.
Discover more at: https://www.planetary.org/planetary-radio/2026-jennifer-vaughn-ceo
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Where did Earth’s water come from? In this episode of Planetary Radio, we explore how scientists are answering that question by studying a remarkably well-preserved record of the early Solar System: lunar samples brought back by the Apollo missions. Host Sarah Al-Ahmed is joined by Tony Gargano, postdoctoral fellow at the Lunar and Planetary Institute with the University Space Research Association and a research affiliate at NASA’s Johnson Space Center. Gargano studies lunar rocks and regolith to understand how planets form, evolve, and acquire key ingredients like water over time. By analyzing subtle chemical fingerprints preserved in Apollo-era lunar regolith, his work helps constrain how much water meteorites could have brought to Earth and what that means for our planet’s path to habitability.
The episode also features a short bonus segment with actor George Takei, recorded at the Academy Museum of Motion Pictures during a screening of “Star Trek IV: The Voyage Home.” Takei reflects on the enduring legacy of “Star Trek,” its influence on generations of scientists and explorers, and why he is excited about humanity’s return to the Moon in the Artemis era. He connects science fiction’s hopeful vision of the future with the real science helping us understand our origins today.
Discover more at: https://www.planetary.org/planetary-radio/2026-earth-water-apollo-moon-dust
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What does a NASA authorization bill actually do, and why does it matter? In this episode of Space Policy Edition, we dig into one of the most misunderstood but powerful tools Congress uses to shape the future of U.S. space exploration.
Host Casey Dreier, chief of space policy at The Planetary Society, is joined by Jack Kiraly, the Society’s director of government relations, for a deep dive into how NASA authorization bills work, how they differ from appropriations, and why they can have decades-long consequences for science missions, human spaceflight, and planetary defense. The discussion also reflects on a major recent win for space advocates: Congress’s bipartisan decision to protect NASA science funding.
Discover more at: https://www.planetary.org/planetary-radio/spe-what-is-a-nasa-authorization-bill
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