Planetary geologist Kirby Runyon is lead author of an abstract that proposes a new, geophysical definition of what a planet is.Learn more about your ad choices. Visit megaphone.fm/adchoices

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Planetary geologist Kirby Runyon is lead author of an abstract that proposes a new, geophysical definition of what a planet is.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee <a href="https://omnystudio.com/listener">omnystudio.com/listener</a> for privacy information.

Planetary Radio brings you the human adventure across our Solar System and beyond. We visit each week with the scientists, engineers, leaders, advocates, and astronauts who are taking us across the final frontier. Regular features raise your space IQ while they put a smile on your face. Join host Sarah Al-Ahmed and Planetary Society colleagues including Bill Nye the Science Guy and Bruce Betts as they dive deep into space science and exploration. The monthly Space Policy Edition takes you inside the DC beltway where the future of the US space program hangs in the balance. Visit planetary.org/radio for an episode guide and much more.

Planetary Radio brings you the human adventure across our Solar System and beyond. We visit each week with the scientists, engineers, leaders, advocates, and astronauts who are taking us across the final frontier. Regular features raise your space IQ while they put a smile on your face. Join host Sarah Al-Ahmed and Planetary Society colleagues including Bill Nye the Science Guy and Bruce Betts as they dive deep into space science and exploration. The monthly Space Policy Edition takes you inside the DC beltway where the future of the US space program hangs in the balance. Visit planetary.org/radio for an episode guide and much more.

Planetary Radio: Space Exploration, Astronomy and Science

Planetary Radio brings you the human adventure across our solar system and beyond. We visit each week with the scientists, engineers, leaders, advocates, and astronauts taking us across the final frontier. Regular features raise your space IQ while they put a smile on your face. Join host Sarah Al-Ahmed and Planetary Society colleagues including Bill Nye, the Science Guy, and Bruce Betts, chief scientist for The Planetary Society, as they dive deep into the latest space news. The monthly Space Policy Edition takes you inside the DC beltway with Casey Dreier and Jack Kiraly to discuss the politics of space exploration in the US and advocacy actions you can take to support the missions that matter. Visit planetary.org/radio for the space trivia contest, an episode guide, and much more.

Planetary Radio brings you the human adventure across our solar system and beyond. We visit each week with the scientists, engineers, leaders, advocates, and astronauts taking us across the final frontier. Regular features raise your space IQ while they put a smile on your face. Join host Sarah Al-Ahmed and Planetary Society colleagues including Bill Nye, the Science Guy, and Bruce Betts, chief scientist for The Planetary Society, as they dive deep into the latest space news. The monthly Space Policy Edition takes you inside the DC beltway with Casey Dreier and Jack Kiraly to discuss the politics of space exploration in the US and advocacy actions you can take to support the missions that matter. Visit planetary.org/radio for the space trivia contest, an episode guide, and much more.

Hope for Pluto—Should We Re-Redefine Planets?

Join us aboard the historic RMS Queen Mary for a celebration of The Planetary Society’s 45th anniversary. In this special episode of Planetary Radio, we bring you highlights from our Cosmic Shores Gala, where members, scientists, space advocates, and special guests came together to honor the past and look boldly to the future.

You’ll hear from CEO Bill Nye, Board President Bethany Ehlmann, Executive Director Jennifer Vaughn, founding Executive Director Lou Friedman, and Congresswoman Judy Chu, with actor and Planetary Society board member Robert Picardo as our master of ceremonies.

And of course, we close with Chief Scientist Bruce Betts in this week’s What’sUp.

Discover more at: https://www.planetary.org/planetary-radio/2025-cosmic-shores-gala

Join us aboard the historic RMS Queen Mary for a celebration of The Planetary Society&rsquo;s 45th anniversary. In this special episode of Planetary Radio, we bring you highlights from our Cosmic Shores Gala, where members, scientists, space advocates, and special guests came together to honor the past and look boldly to the future.
You&rsquo;ll hear from CEO Bill Nye, Board President Bethany Ehlmann, Executive Director Jennifer Vaughn, founding Executive Director Lou Friedman, and Congresswoman Judy Chu, with actor and Planetary Society board member Robert Picardo as our master of ceremonies.
And of course, we close with Chief Scientist Bruce Betts in this week&rsquo;s What&rsquo;s Up.
Discover more at: <a href="https://www.planetary.org/planetary-radio/2025-cosmic-shores-gala">https://www.planetary.org/planetary-radio/2025-cosmic-shores-gala</a>

Join us aboard the RMS Queen Mary as we celebrate 45 years of The Planetary Society at our Cosmic Shores Gala, featuring reflections from Bill Nye, Bethany Ehlmann, Jennifer Vaughn, and more.

Celebrating 45 years of The Planetary Society at the Cosmic Shores Gala

NASA’s science programs are facing the largest proposed budget cut in more than 40 years. This staggering 47%reduction could cancel missions, waste billions in U.S. taxpayer investments, and unravel decades of discovery. In this episode of Planetary Radio, host Sarah Al-Ahmed is joined by Casey Dreier, The Planetary Society’s Chief of Space Policy, and Jack Kiraly, Director of Government Relations. Together, they break down what the “passback” stage of the federal budget process means for NASA, which missions and programs are in jeopardy, and how you can help push back. Later in the show, Chief Scientist Bruce Betts joins us for a reflective What’s Up as we explore the science that could be lost and why it still deserves to be saved.

Discover more at: https://www.planetary.org/planetary-radio/2025-passback-budget-breakdown

NASA&rsquo;s science programs are facing the largest proposed budget cut in more than 40 years. This staggering 47%reduction could cancel missions, waste billions in U.S. taxpayer investments, and unravel decades of discovery. In this episode of Planetary Radio, host Sarah Al-Ahmed is joined by Casey Dreier, The Planetary Society&rsquo;s Chief of Space Policy, and Jack Kiraly, Director of Government Relations. Together, they break down what the &ldquo;passback&rdquo; stage of the federal budget process means for NASA, which missions and programs are in jeopardy, and how you can help push back. Later in the show, Chief Scientist Bruce Betts joins us for a reflective What&rsquo;s Up as we explore the science that could be lost and why it still deserves to be saved.
Discover more at:&nbsp;<a href="https://www.planetary.org/planetary-radio/2025-passback-budget-breakdown">https://www.planetary.org/planetary-radio/2025-passback-budget-breakdown</a>

NASA's science programs face a proposed 47%budget cut. We break down what's at risk and how you can take action to help protect space exploration.

Passback budget breakdown: A 47% cut to NASA science

For decades, scientists hypothesized that Mars’ reddish color came from hematite, an iron oxide thought to have formed through dry oxidation after Mars lost its water. But new research suggests the story is more complex—and more watery—than we once imagined.

In this episode, planetary scientist Adomas (Adam) Valantinas from Brown University joins host Sarah Al-Ahmed to discuss his team’s discovery that Mars’ iconic red dust is likely dominated not by hematite but by a hydrated mineral called ferrihydrite. This subtle but significant shift in understanding could reshape what we know about Mars’ climate history and its potential for past habitability. 

Then, Sarah and Bruce Betts, Planetary Society chief scientist, revisit one of the most famous Martian discoveries: Opportunity’s hematite-rich “blueberries,” which also told a compelling story about water on the Red Planet.

Discover more at: https://www.planetary.org/planetary-radio/2025-why-is-mars-red

For decades, scientists hypothesized that Mars&rsquo; reddish color came from hematite, an iron oxide thought to have formed through dry oxidation after Mars lost its water. But new research suggests the story is more complex&mdash;and more watery&mdash;than we once imagined.
In this episode, planetary scientist Adomas (Adam) Valantinas from Brown University joins host Sarah Al-Ahmed to discuss his team&rsquo;s discovery that Mars&rsquo; iconic red dust is likely dominated not by hematite but by a hydrated mineral called ferrihydrite. This subtle but significant shift in understanding could reshape what we know about Mars&rsquo; climate history and its potential for past habitability.&nbsp;
Then, Sarah and Bruce Betts, Planetary Society chief scientist, revisit one of the most famous Martian discoveries: Opportunity&rsquo;s hematite-rich &ldquo;blueberries,&rdquo; which also told a compelling story about water on the Red Planet.
Discover more at:&nbsp;<a href="https://www.planetary.org/planetary-radio/2025-why-is-mars-red">https://www.planetary.org/planetary-radio/2025-why-is-mars-red</a>

Why is Mars red? A new study led by Brown University’s Adomas Valantinas points to ferrihydrite, not hematite, revealing a wetter past and new clues about the Red Planet’s potential to support life.

Hope for Pluto—Should We Re-Redefine Planets?

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