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. Watch on Youtube: https://youtu.be/YOlOuBYgAmQ

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 (e.g. https://www.cambridge.org/core/books/causal-fermion-systems/CCA6DE1E1F4DA3AC0EF6729664A5D5B9 ).

►Watch on YouTube: https://youtu.be/qQl51qifus0

►Find out more about Felix's work here: https://www.uni-regensburg.de/mathematik/mathematik-1/startseite/index.html https://causal-fermion-system.com/

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? ►Watch on YouTube: https://youtu.be/YiX5GKDtYWY ►Find out more about Aubrey's work here: https://www.levf.org/team https://www.levf.org/projects/robust-mouse-rejuvenation-study-1/study-updates