Episode notes
For decades, string theory has been hailed as the leading candidate for the theory of everything in our universe. Yet despite its mathematical elegance, the theory still lacks empirical evidence. One of its most intriguing, yet vexing, implications is that if all matter and forces are composed of vibrations of tiny strands of energy, then this allows for a vast landscape of possible universes with different physical properties, varieties of particles and complex spacetimes. How, then, can we possibly pinpoint our own universe within a field of almost infinite possibilities? Since 2005,…
The Joy of Why
by Steven Strogatz, Janna Levin and Quanta Magazine · English · Tech & Science
“The Joy of Why” is a Quanta Magazine podcast about curiosity and the pursuit of knowledge. The mathematician and author Steven Strogatz and the cosmologist and author Janna Levin take turns interviewing leading researchers about the great scientific and mathematical questions of our time. New…
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S4 · E9 · 10 Jul 2025 · 45 min
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Climate models have changed the way we view the world. While effective, these models are imperfect, and scientists are constantly looking at ways to improve their accuracy and predictability. MIT professor Elfatih Eltahir has spent decades developing complex models to understand how climate change affects vulnerable regions like the Nile Basin and Singapore. In this episode of The Joy of Why, Eltahir tells co-host Steven Strogatz how growing up near the Nile in Sudan helped him realize that climate change doesn’t occur in isolation. To better understand climate-related impacts and to create…
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S4 · E8 · 26 Jun 2025 · 34 min
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S4 · E7 · 12 Jun 2025 · 47 min
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S4 · E5 · 15 May 2025 · 46 min
How Did Geometry Create Modern Physics?
Geometry is one of the oldest disciplines in human history, yet the worlds it can describe extend far beyond its original use. What began thousands of years ago as a way to measure land and build pyramids was given rigor by Euclid in ancient Greece, became applied to curves and surfaces in the 19th century, and eventually helped Einstein understand the universe. Yang-Hui He sees geometry as a unifying language for modern physics, a mutual exchange in which each discipline can influence and shape the other. In the latest episode of The Joy of Why, He tells co-host Steven Strogatz how geometry…
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S4 · E4 · 1 May 2025 · 42 min
Will AI Ever Understand Language Like Humans?
Large language models (LLMs) are becoming increasingly more impressive at creating human-like text and answering questions, but whether they can understand the meaning of the words they generate is a hotly debated issue. A big challenge is that LLMs are black boxes; they can make predictions and decisions on the order of words, but they cannot communicate the reasons for doing so. Ellie Pavlick at Brown University is building models that could help understand how LLMs process language compared with humans. In this episode of The Joy of Why, Pavlick discusses what we know and don’t know about…
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S4 · E3 · 17 Apr 2025 · 43 min
Can Quantum Gravity Be Created in the Lab?
Quantum gravity is one of the biggest unresolved and challenging problems in physics, as it seeks to reconcile quantum mechanics, which governs the microscopic world, and general relativity, which describes the macroscopic world of gravity and space-time. Efforts to understand quantum gravity have been focused almost entirely at the theoretical level, but Monika Schleier-Smith at Stanford University has been exploring a novel experimental approach — trying to create quantum gravity from scratch. Using laser-cooled clouds of atoms, she is testing the idea that gravity might be an emergent…
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S5 · E9 · 1 Oct 2026 · 53 min
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We know all about how things exist in the three dimensions of length, width, and height. Physicists often talk about time as a fourth dimension, but what if there were a fourth spatial dimension — another direction entirely? How on earth would we picture that? Mathematicians use topology to visualize abstract spaces in higher dimensions. Maggie Miller at the University of Texas at Austin explores what happens when knots encounter an extra dimension. Familiar tangled loops behave in unexpectedly complex and counterintuitive ways in 4D: Knots can always come undone, while ordinary surfaces…
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17 Sep 2026 · 47 min
Where Does the Quantum World End and Ours Begin?
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3 Sep 2026 · 53 min
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S5 · 20 Aug 2026 · 52 min
Are We Thinking Correctly about AI Intelligence?
When an LLM answers a question, is it reasoning like humans, or just producing text that looks like reasoning? The distinction isn’t just philosophical, this determines what we can trust AI to do, how closely we need to supervise it, and ultimately what its real-world impact will turn out to be. Melanie Mitchell at the Santa Fe Institute argues that we lack adequate methods for measuring machine cognition, and that AI is a form of “alien intelligence” that operates through non-human cognitive mechanisms. In this episode of The Joy of Why, Mitchell tells Steven Strogatz how methods that…
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