The Joy of Why

Shep Doeleman discusses how the Event Horizon Telescope connected radio observatories around the world to resolve the shadows of supermassive black holes. With Janna Levin, he explains the scientific and technical challenges of imaging M87* and the Galactic centre, what the observations can test about black holes, and the ambition to move from still images to movies.

Hosted by Janna Levin, Steven Strogatz

Evolutionary biologist Toby Kiers joins Steven Strogatz to explore how mycorrhizal fungi exchange nutrients with plants and influence soil carbon storage. The conversation examines decentralized resource allocation, partnerships between fungi and roots, and experiments using fluorescent tracers and imaging robots to observe underground networks. Kiers also describes efforts to map fungal biodiversity and protect these ecosystems.

Hosted by Steven Strogatz, Janna Levin

Mathematician Maggie Miller of the University of Texas at Austin joins Janna Levin and Steven Strogatz to explore knots, surfaces and four-dimensional topology. They discuss why loops can untangle in four spatial dimensions while two-dimensional surfaces can remain knotted, how three-dimensional snapshots help visualize 4D spaces, and Miller and collaborators’ resolution of a knotted-surface question posed by Charles Livingston in 1982. The conversation also connects visual techniques from art with mathematical reasoning.

Hosted by Janna Levin, Steven Strogatz

Theoretical physicist Jonathan Halliwell joins Steven Strogatz and Janna Levin to discuss how quantum decoherence helps explain the transition from wave-like quantum systems to the classical macroscopic world. The conversation covers quantum cosmology, decoherent histories, the measurement problem, macroscopic realism and why the quantum-to-classical transition does not require a conscious observer.

Hosted by Steven Strogatz, Janna Levin

Recorded live at the International Congress of Mathematicians in Philadelphia, this episode brings hosts Janna Levin and Steven Strogatz together with Akshay Venkatesh, Ravi Vakil and Alex Kontorovich. They examine what recent AI-generated proofs demonstrate, how machine assistance may change mathematical research, and what proof, creativity, understanding and storytelling contribute to the discipline. The recording took place on 26 July 2026; Quanta published the episode on 3 September 2026.

Hosted by Janna Levin, Steven Strogatz

Computer scientist and cognitive scientist Melanie Mitchell discusses why artificial intelligence does not think or reason like humans, how developmental and comparative psychology can improve machine-cognition experiments, and six principles for testing AI competence, robustness, and failure modes.

Ishmail Abdus-Saboor explores why touch can feel painful or pleasurable and how scientists study those experiences. The conversation connects sensory pathways to social behavior and evolution, including work with unusual animal models and the challenge of interpreting subjective experience through experiments.

Hosted by Janna Levin

Adam Riess explains how astronomers measure the universe's expansion and why different methods give conflicting results. He revisits the evidence for accelerated expansion and examines what the Hubble tension might reveal about measurement techniques or missing ingredients in cosmological models.

Hosted by Steven Strogatz

David Kipping considers how to reason about extraterrestrial life when evidence is scarce. The discussion covers promising places to search, the interpretation of possible biosignatures and the role of statistical inference, alongside questions about habitable worlds and moons beyond our solar system.

Hosted by Janna Levin

Lauren Williams introduces the positive Grassmannian and the surprising connections it creates across mathematics and physics. She explains links to waves, traffic and particle scattering, and discusses how research-level mathematical problems can help assess what artificial intelligence is capable of proving.

Hosted by Steven Strogatz

Jennifer Doudna discusses how CRISPR changed gene editing and what might come next. The conversation examines emerging applications, technical limitations and the ethical choices involved in altering genetic material, including how scientific progress can be paired with responsible use.

Hosted by Janna Levin

Thomas Hertog discusses his work with Stephen Hawking on the origin of the Universe and a proposal in which physical laws develop alongside cosmic history. The conversation with Janna Levin examines the role of observers, the limits of multiverse explanations and how the conditions compatible with life might emerge. The proposed framework is discussed as a theoretical approach to unresolved questions.

Hosted by Janna Levin, Steven Strogatz

Elfatih Eltahir explains how regional climate models can incorporate disease, population and other local conditions to guide adaptation. Drawing on work in the Nile Basin and Singapore, he discusses the limitations of global predictions, his Equation of the Future of Africa, and outdoor days as a more tangible measure of climate impacts.

Hosted by Steven Strogatz, Janna Levin

Maria Chudnovsky introduces graph theory through relationships represented as vertices and edges. She discusses the perfect graph problem, practical uses of abstract structure and her path into mathematics, including an application to wedding seating, in conversation with Janna Levin.

Hosted by Janna Levin, Steven Strogatz

L. Mahadevan investigates how geometry, mechanics and randomness connect form with function. With Steven Strogatz, he considers Möbius strips, brain folds, termite colonies and morphogenesis, showing how experiments with simple materials can illuminate biological organization and the role of noisy processes in geometric intuition.

Hosted by Steven Strogatz, Janna Levin

Cumrun Vafa discusses the gap between string theory's mathematical possibilities and experimental tests. The conversation considers the landscape of candidate universes, the swampland programme for ruling out inconsistent possibilities, dimensional constraints and the role of cosmological observations in seeking predictions relevant to our Universe.

Hosted by Janna Levin, Steven Strogatz

Yang-Hui He joins Steven Strogatz to trace geometry from ancient measurement and Euclid to curved spaces, general relativity, and string theory. They discuss why geometry provides a shared language for mathematics and physics, how rigorous proof interacts with physical intuition, and how artificial intelligence might change mathematical discovery. The conversation also contrasts broad conceptual views with concentrated work on individual problems.

Hosted by Steven Strogatz, Janna Levin

Ellie Pavlick examines what it would mean for a language model to understand words. She compares machine and human language processing, discusses the difficulty of explaining black-box predictions, and considers how studying these differences might clarify both artificial intelligence and human knowledge and creativity.

Hosted by Janna Levin, Steven Strogatz

Monika Schleier-Smith explores experiments with laser-cooled atoms intended to probe links between quantum entanglement and emergent gravity. She discusses the risks and potential insights of constructing quantum-gravity analogues, including what such systems could teach about many-body quantum physics even without achieving the long-term simulation goal.

Hosted by Janna Levin, Steven Strogatz

Ewin Tang discusses dequantization: designing classical algorithms inspired by proposed quantum advantages. The conversation starts with recommendation algorithms and considers the continuing contest between quantum and classical computation, the role of failure in research and how to evaluate the practical promises made for quantum machines.

Hosted by Janna Levin, Steven Strogatz