Journey to the Center of Jupiter: Creating Fantastic Pressure With the World’s Largest Lasers

Episode Summary

Executive Summary: This Planetary Radio episode spans three science stories: a Mars comet flyby that should be observed safely by orbiters and rovers, the recovery of interstellar dust returned by Stardust, and groundbreaking laser experiments at NIF showing unexpected behavior of diamond under extreme pressures relevant to giant-planet interiors. The episode ends with space news, trivia, and night-sky viewing tips.

Main Topics: Mars spacecraft prepare for a close comet encounter: Emily Lakdawalla explains that Mars orbiters and rovers will observe a long-period comet passing near Mars, while some spacecraft use Mars itself as a shield during closest approach to protect against potential dust impacts. Comet science and atmospheric interactions at Mars: The discussion highlights planned observations of the comet nucleus, coma structure, rotation, brightness, and how the coma may interact with Mars' atmosphere, including MAVEN’s role in studying that interaction. Interstellar dust returned by Stardust: Bill Nye describes the identification of tiny grains believed to be true interstellar dust, recovered from Stardust's collection medium by volunteer particle hunters and used to address questions about our origins and life in the universe. Extreme-pressure physics at the National Ignition Facility: Rip Collins discusses using NIF’s 192 beams and two-megajoule laser system to compress diamond to conditions comparable to giant-planet cores, revealing unexpected high-pressure behavior. Revising models of giant planets and matter under pressure: The interview explains that at tens of millions of atmospheres, matter may not behave as formerly expected; instead of simple close packing, core electrons and ionic structures may become important, altering planetary interior models. Planetary Society updates, trivia, and skywatching: Bruce Betts delivers weekly sky highlights, space-history notes, a trivia answer about Sojourner, and a new contest about the pocket mice flown on Apollo 17, wrapping the show in the Planetary Society’s community and outreach style.

Key Arguments: Mars can be used as a protective shield for orbiters during a comet flyby, reducing risk from dust impacts. A long-period comet never before in the inner solar system offers a rare opportunity for coordinated observations across Mars missions. The comet’s coma, nucleus, spin rate, and surface brightness can reveal whether comets are inherently dark or darken through repeated solar heating. Recovered Stardust particles are valuable because they are likely genuine interstellar dust, offering direct evidence from outside the solar system. Tiny dust grains can answer major questions about the origin of the solar system and life, despite being microscopic. NIF’s laser capability can replicate extreme pressures found in giant planets, giving laboratory access to conditions previously inferred only indirectly. At such pressures, carbon behaves more stiffly than expected, suggesting current models of planetary interiors need revision. High-pressure physics may involve core-electron behavior and ionic structures rather than only simple electron delocalization and close packing. Basic research built for one goal, such as fusion energy, can yield transformative discoveries in unexpected fields.

Data Points: NIF laser count: 192 beams - Used at the National Ignition Facility to illuminate targets Laser energy: 2 megajoules - Blue light energy delivered by NIF Comet observation duration: at least a week's worth of observations - Planned coordinated observations by Mars spacecraft Interstellar dust age: 100 million years old - Bill Nye says the dust recovered from Stardust is believed to be this old Number of particles identified: 7 particles - Volunteers identified seven likely interstellar particles in Stardust collector material Pressure at Earth’s center: about 4 million atmospheres - Rip Collins compares deep-Earth pressure to planetary interior conditions High-pressure regime studied: tens of millions of atmospheres - Conditions reached in the diamond compression experiments Compression target density: 1.5 kilograms per cc - Described as the compressed density reached in inertial confinement fusion context Original hydrogen density: about one-fifth the density of water - Initial density of the hydrogen shell in the fusion example Comparable pressure levels: tens to hundreds of atmospheres - Deep-ocean pressures where metabolic processes begin to change Moon discovery timing: 17 days after Neptune’s discovery - Bruce Betts’ space fact about Triton Trivia contest date deadline: August 26, 8 a.m. Pacific Time - Deadline for answering the Apollo 17 pocket mice question Historical launch years: 1975, 1976, 1977 - Viking 1, Luna 24 return, and Voyager 2 launches noted in space history

Pivotal Quotes: "It’s been a long time since I’ve left you a special message." — Matt Kaplan: Opening host message encouraging ratings and reviews "We live in a universe that is filled with this exotic material all around us, and we never knew it existed." — Rip Collins: On the broader significance of high-pressure matter in giant planets "I really believe that over the next decade, the science that will be really most profoundly impacting humans, we haven’t thought of." — Rip Collins: On the serendipity of basic research and large scientific facilities

Implications: Listeners get a snapshot of how space missions, returned samples, and lab experiments can together reshape planetary science. The episode underscores the value of serendipitous discovery, citizen science, and fundamental research for future exoplanet and solar-system models.