For over forty years, Dutch geologist and paleontologist Jan Smit has been at the center of one of the most profound scientific detective stories of our time: the investigation into the mass extinction that ended the reign of the dinosaurs 66 million years ago. Known as the Cretaceous-Paleogene (K-Pg) extinction, this event wiped out nearly 75% of all species on Earth, from towering dinosaurs to microscopic marine life, and cleared the way for the rise of mammals and, eventually, humans.

Early in his career, Jan Smit became intrigued by a thin layer of clay found in rock strata across the globe, precisely at the boundary between Cretaceous and Paleogene sediments. This layer, unusually rich in the rare element iridium, held clues that would eventually transform our understanding of planetary history. Working alongside Luis and Walter Alvarez and others, Jan helped develop the hypothesis that a massive asteroid impact, rather than volcanic activity or gradual climate change, was the primary cause of the extinction.

In this episode, we explore the extraordinary evidence for that theory: global patterns of shocked quartz, tsunami deposits, a massive crater buried beneath the Yucatán Peninsula, and the sudden disappearance of entire ecosystems in the fossil record. Jan walks us through decades of fieldwork and analysis that revealed the incredible violence and planetary consequences of the impact, a blast more powerful than a billion Hiroshima bombs, throwing Earth into a global winter.

But this is more than a forensic tale of catastrophe. It's a window into the fragility and resilience of life, the interconnectedness of geological and biological systems, and the awe-inspiring forces that shape the story of our planet.

For over three decades, Felix Finster has been developing a unique and ambitious reformulation of physics known as Causal Fermion Systems (CFS). Physicists usually describe the world in terms of fields defined on a spacetime manifold. Within this familiar framework, abstract quantities such as correlations between matter fields at different points in spacetime can be computed. In mathematical language, these correlations are captured by operators acting on a Hilbert space.

What Felix realized is that this process can be reversed. If you start with a suitable collection of operators on a Hilbert space, satisfying certain mathematical properties, you can in principle reconstruct the underlying spacetime and fields that would give rise to those operators as operators of correlations.

In this sense, Causal Fermion Systems  offers a dual description of reality. On the one hand, reality can be described in terms of symmetries, fields, and manifolds - the usual language of physics. On the other hand, CFS proposes that reality can just as well be described using abstract structures: Hilbert spaces, operators, and measures on sets of operators. Spacetime, matter, and everything we observe then emerges from these underlying mathematical quantities.

The beauty of reformulating physics this way is that it opens up an entirely new framework in which to explore some of the deepest open questions in physics: What is spacetime like at the smallest scales? Why do we see precisely the particles we do in experiments? The hope is that within the CFS framework, answers to such questions might become more natural or even inevitable.

Of course, we can’t cover a 30-year research program in full detail in a single conversation. The goal here is to get a sense of the flavor of Felix’s approach to physics. For the full details, you can explore Felix's books 

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Aging has long been treated as inevitable. But what if it’s not? What if aging is, at its core, a problem to be solved? In this episode, I speak with biomedical gerontologist Aubrey de Grey about the most ambitious anti-aging experiment ever conducted on mice. The Robust Mouse Rejuvenation (RMR) study, spearheaded by Aubrey and the Longevity Escape Velocity Foundation, aims to extend both the average and maximum lifespan of mice by at least 12 months—a staggering leap in a species that typically lives around 30 months. We unpack the science behind this bold endeavor: What is aging? Why aim for rejuvenation and damage repair as opposed to slowing down aging? What interventions are being trialed in mice? What are the best achievable results? What does the blueprint for longevity escape velocity look like?

Richard Feynman once dubbed turbulence “the last unsolved problem of classical physics.” Beyond the Navier–Stokes equations, no comprehensive statistical framework exists to predict how fluids spin, eddy, and cascade energy—whether in galactic jets, ocean currents, or the swirl of your morning coffee. But that might all be changing.

In this episode, I sit down with theoretical physicist Sasha Migdal, who emerged from retirement with a bold, loop‑equation approach to turbulence. His formalism recasts the Navier–Stokes equations as an infinite number of linear, readily solvable equations that track circulation around closed loops in the fluid—offering, for the first time, a tractable statistical framework for chaotic flow.

We chart Sasha’s remarkable journey: from a promising career at the Landau Institute and Russian Space Institutes, where he resisted KGB pressure to compromise his work, to his defection to the United States in the late 1980s. We discuss his time outside of physics, and then delve into his return, and his novel approach to solving Navier–Stokes. 

Since we recorded, his theory has advanced rapidly. A rigorous proof now shows that it is the solution 

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►For a more technical overview of Sasha's work you can check out his recent talk at the IAS:

In this conversation I ask Professors Sam Richards & Laurey Mulvey about some of the most controversial topics concerning race and ethnicity in the US today.

Is White Privilege a useful term that helps build understanding and facilitates conversation, or does it generate social tension and make poor white people feel gaslit? What is DEI, why is it so contentious, and can it be implemented effectively? What makes the N-word and blackface so triggering? Why are US racial social norms so culturally dominant and readily exported? 

Sam Richards is a sociologist and Teaching Professor at Penn State and a Distinguished Professor at Konkuk University in Seoul, Korea. He runs SOC119, which is the largest race, ethnicity and cultural relations course in the world. Every Tuesday and Thursday afternoon his class is live streamed to 370,000 subscribers from around the world, and his classes have had over 400 million views. His willingness to challenge orthodox thinking led him to be named one of the “101 Most Dangerous 

Laurie Mulvey is the director and co-founder of the World in Conversation Center for Public Diplomacy at Penn State, which is the largest dialogue center in the United States, hosting more than 17,000 participants each academic year. The Center has worked with the UNDP, UNESCO, and NATO, along with organizations and universities in Afghanistan, Pakistan, Iran, Palestinian Territories, Israel, Kuwait, Qatar, China, Haiti, Saudi Arabia, and twelve nations in the NATO Alliance to host dialogues between people separated by vast distances and borders. Laurie is a master facilitator, focused on moderating beneficial conversations between different groups on some of the most difficult, hot button topics.

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These conversations are supported by the Andrea von Braun foundation (http://www.avbstiftung.de/), as an exploration of the rich, exciting, connected, scientifically literate, and (most importantly) sustainable future of humanity. The Andrea von Braun Foundation has provided me with full creative freedom with their support. As such, the views expressed in these episodes are my own and/or those of my guests.

What is Holography and how does it help us Quantize gravity? In this conversation I speak with Pedro Vieira, one of the worlds leading experts on holographic dualities and their application in quantum gravity.

We start our discussion with a few standard but big questions, like why is quantum gravity difficult, what is quantum field theory, and what is gauge symmetry. We then dive into the topic of holography, which in broad and provocative terms is the idea that our universe and everything in it might be a hologram projected from some lower dimensional quantum theory. That is, there might be a duality between the mathematics that describes our world including gravity and the mathematics that describes a world with quantum mechanics and without gravity in one dimension lower. If such a duality were true, then it might provide a radial way of side stepping all of the usual difficulties of quantizing gravity. 

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These conversations are supported by the Andrea von Braun foundation (http://www.avbstiftung.de/), as an exploration of the rich, exciting, connected, scientifically literate, and (most importantly) sustainable future of humanity. The Andrea von Braun Foundation has provided me with full creative freedom with their support. As such, the views expressed in these episodes are my own and/or those of my guests.

In this conversation I speak with Sam Bendett, one of the worlds leading experts on Russian weapons development and capabilities, drones, AI, and the war in Ukraine. Sam is an advisor for the Center for Naval Analyses and an adjunct senior fellow at the Center for a New American Security, an honorary “mad scientist” with the Mad Scientist Initiative of the U.S. Army Training and Doctrine Command, and a Russian military autonomy and artificial intelligence subject matter expert for the DOD’s Defense Systems Information Analysis Center.

We discuss drone warfare in Ukraine as it stands today. We cover the range of systems being fielded, counter measures, AI capabilities, what life is like for drone operators and soldiers on the line of contact, drone production pipelines and supply, and more.

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These conversations are supported by the Andrea von Braun foundation (http://www.avbstiftung.de/), as an exploration of the rich, exciting, connected, scientifically literate, and (most importantly) sustainable future of humanity. The Andrea von Braun Foundation has provided me with full creative freedom with their support. As such, the views expressed in these episodes are my own and/or those of my guests.

Will we ever have an AI for president? In this episode of the podcast I speak with Pedro Domingos about the impact of AI on society, industry, and politics. Pedro is professor emeritus of computer science and engineering at the University of Washington and co-founded the International Machine Learning Society. He is also the Author of `The Master Algorithm' and `2040: A Silicon Valley Satire'. This episode is not a paid advertisement for Pedro's books, but we use his book `2040' to set the context for the discussion. 

We discuss the hype and fear surrounding AI and the future of tech, and Pedro gives an insiders view into the realities of AI development and impact. In his view AI is a human made tool. It isn't going to take over the planet like the terminator, but it will be something that is used by humans to shift the balance of power in society, industry, and politics. A particularly interesting aspect of the discussion surrounds digital twins. Imagine a world in which dating apps are replaced with a digital platform in which your digital twin simulates dates, and even entire lives with the digital twins of potential partners. Users would then go on physical dates with the top performing selection. This same idea could be extended to predicting crime, presidential election outcomes, and more. All of a sudden the simulation hypothesis doesn't seem to crazy, when simulations are used to predict future outcomes in the real world.

Another key topic in this conversation is that of `wokism'. Pedro discusses `wokism' as a new iteration of cultural marxism, an ideology that reinterprets the dynamics of class struggle through cultural and identity-based lenses. While the creation of wealth in a society is not inherently a zero-sum game—where one person’s gain is necessarily another’s loss— the division and redistribution of that wealth that has been created is a zero-sum conflict. Pedro suggests that `wokism' is an attempt to shift power and resources within society, but where the division between the oppressed and the privileged is identity based.

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These conversations are supported by the Andrea von Braun foundation (http://www.avbstiftung.de/), as an exploration of the rich, exciting, connected, scientifically literate, and (most importantly) sustainable future of humanity. The Andrea von Braun Foundation has provided me with full creative freedom with their support. As such, the views expressed in these episodes are my own and/or those of my guests.

In this conversation I speak with renegade economist and creator of doughnut economics Kate Raworth. Kate is a Senior Associate at Oxford University’s Environmental Change Institute, where she teaches on the Masters in Environmental Change and Management. She is also Professor of Practice at Amsterdam University of Applied Sciences.

We speak about economic transformation, and re-imagining economic possibilities for the 21st century. What should we design our economic system to do? Growth in GDP is a nice target to aim for because it is simple, but it doesn't do a very good job of capturing all of the economic externalities associated with market contracts, and in particular the impact of doing business on the environment and human well being. Our economies are beginning to run up against our planets boundaries, and it is becoming increasingly apparent that our planet is finite. So what should our target be if not for endless growth in GDP at the expense of our only known habitable planet?

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These conversations are supported by the Andrea von Braun foundation (http://www.avbstiftung.de/), as an exploration of the rich, exciting, connected, scientifically literate, and (most importantly) sustainable future of humanity. The Andrea von Braun Foundation has provided me with full creative freedom with their support. As such, the views expressed in these episodes are my own and/or those of my guests.

This conversation is the second part of a two part mini-series on Regenerative cattle farming. The question is: Does raising cattle really have to be so damaging to the environment? Can cattle be integrated into a natural system that sequesters carbon from the atmosphere, and if so what would that system look like?

Joel Salatin segregates his land into small fenced off areas, which he rotates his cattle through. By moving his herd routinely he gives grass and other wild vegetation optimal time to grow and absorb carbon, and for the cattle to disperse their excreta such that it is optimally absorbed into the fields. By dispersing the impact of his cattle, and introducing a number of complimentary species he is able to reduce the impact of disease and pests without the use of insecticides, pesticides, and other chemical based management approaches. This keeps the soil alive such that smaller organisms can work the carbon deposited by the cattle into the soil. The claim is that this approach is able to sequester carbon. Its also far better for the animals, and leads to a better end product.

At 21:00 Joel mentions a connection between autism, and nutrition. The exact causes of autism are not fully understood, but research points to a combination of genetic, environmental, and possibly prenatal influences. Maternal nutrition during pregnancy (including adequate levels of folic acid and vitamin D), gut health, and nutritional deficiencies may influence autism-related symptoms, though no definitive dietary cause has been identified and specialized diets show mixed evidence and require further research.

At 1:16:00  Joel mentions health comparisons between Fake meat Substitutes and real beef. I don't know much about that topic yet, but here is somewhere to start looking if you are interested:

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►Find out more about Polyface Farm Here:

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These conversations are supported by the Andrea von Braun foundation (http://www.avbstiftung.de/), as an exploration of the rich, exciting, connected, scientifically literate, and (most importantly) sustainable future of humanity. The Andrea von Braun Foundation has provided me with full creative freedom with their support. As such, the views expressed in these episodes are my own and/or those of my guests.