An Encore for Sir Arthur and Another New Extrasolar Planet

Episode Summary

Executive Summary: This Planetary Radio episode mixes a classic interview with Sir Arthur C. Clarke, a science update on extrasolar planets, a listener Q&A on asteroid/comet orbit calculation, and Bruce Betts’s skywatching, trivia, and mission news. The show highlights Clarke’s work in progress, The Last Theorem, and emphasizes how modern astronomy combines Newtonian orbits with computer modeling and exoplanet discoveries.

Main Topics: Sir Arthur C. Clarke interview and literary reflections (Priority: 5/5): Matt Kaplan revisits a conversation with Clarke about science fiction history, his friendships with fellow authors, favorite works, Tolkien, Kubrick’s 2001, and his current novel The Last Theorem. The Last Theorem and mathematics in fiction (Priority: 5/5): Clarke explains that his new novel centers on Fermat’s Last Theorem, a centuries-old mathematical puzzle, and follows a Tamil mathematician from Sri Lanka to Mars. Exoplanet discovery update (Priority: 5/5): Amir Alexander discusses a newly found extrasolar planet system that more closely resembles our solar system than previous detections, though it still lacks an Earth-like world. How astronomers calculate comet and asteroid orbits (Priority: 4/5): Emily Lochdawala answers a listener question by explaining that orbital paths are estimated by fitting observations to ellipses and refined with many measurements and numerical simulation. Bruce Betts’s skywatching and space history segment (Priority: 4/5): Bruce provides planet-viewing advice, space-history notes, a trivia result, a new contest question, and updates on Planetary Society astrobots and Mars mission status. Planetary Society outreach and missions (Priority: 3/5): The episode includes promotional messaging about membership, the Planetary Report, the website, solar sail efforts, and ongoing support for Mars exploration and near-Earth object tracking.

Key Arguments: Orbital prediction starts with Keplerian ellipses, but close encounters with planets require computer simulations because exact three-body solutions are not available in closed form. Clarke argues that science fiction writers of his generation largely avoided personal enmity and functioned as a supportive community. Clarke frames The Last Theorem as a rare Earth-and-Mars story centered on a young mathematician and a famous unsolved theorem. The newly discovered exoplanet system is notable because it contains a Sun-like star and a giant planet at a distance more like Jupiter’s orbit, unlike the many hot Jupiters previously found. A Jupiter-like giant planet far from the star is important because it may shield inner planets and help allow Earth-like planet formation. The presence of a giant planet migrating close to a star is generally bad news for nearby Earth-like worlds. Mars is presented as the most prominent planet in the evening sky at the time of broadcast, with Jupiter low and setting. Pluto’s bright-dark contrast is mentioned as unusually high, underscoring how little is still known about the dwarf planet.

Data Points: Observed positions needed to determine an orbit: 3 - Emily explains that as few as three precise observations at different times can define an orbital ellipse in principle. Approximate accuracy of asteroid position prediction: A few tens of miles - Emily says modern simulations can project asteroid positions with very high precision. Known extrasolar planets at the time: 100 odd - Amir describes the new planet as different from the roughly hundred extrasolar planets already discovered. Planet size: About twice the size of Jupiter - Amir describes the newly found giant planet in the exoplanet system. Orbital distance of new giant planet: About two-thirds of Jupiter’s distance from the Sun - Used to explain why this system resembles our own more than earlier exoplanet discoveries. Jupiter’s orbital period: 12 years - Amir contrasts Jupiter’s orbit with hot Jupiters that complete orbits in days or weeks. Hot Jupiter orbital period: Days or weeks - Amir notes the typical period for many previously discovered giant exoplanets close to their stars. Bigger diameter of strap-on boosters: 6 inches - Bruce gives the answer to the prior trivia contest about Delta II heavy boosters. Biff Starling distance from Earth: Over 6 million kilometers - Bruce updates the location of the Planetary Society astrobot on the Mars Exploration Rover mission. Clarke’s novel progress: About one quarter written - Clarke says he has written roughly a quarter of The Last Theorem. Time since Pluto contrast observation: Not specified - Bruce notes Pluto has the highest bright-dark contrast of any observed planet on the scale discussed.

Pivotal Quotes: "Mars doesn't harbor life, it's infested." — Sir Arthur C. Clarke: Clarke jokes about his increasingly strong belief that Mars may contain life based on orbital imagery. "Any sufficiently advanced technology is indistinguishable from magic." — Sir Arthur C. Clarke: Referenced near the close of the interview as a signature Clarke maxim. "The method that scientists use to track comets and asteroids is a perfect example of how we are still indebted to Copernicus, Kepler, and Newton." — Emily Lochdawala: Opening explanation of how orbit determination works.

Implications: Listeners get a snapshot of how astronomy, computation, and exploration intersect: classical orbital mechanics still matters, exoplanet searches are edging toward solar-system analogs, and Mars/solar-system exploration remains active and public-facing.