The Joy of Why
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49 episodes
It’s fair to say that enjoyment of a podcast would be severely limited without the human capacity to create and understand speech. That capacity has often been cited as a defining characteristic of our species, and one that sets us apart in the long history of life on Earth. Yet we know that other species communicate in complex ways. Studies of the neurological foundations of language suggest that birdsong, or communication among bats or elephants, originates with brain structures similar to our own. So why do some species vocalize while others don’t? In this episode, Erich Jarvis, who studies behavior and neurogenetics at the Rockefeller University, chats with Janna Levin about the surprising connections between human speech, birdsong and dance.
Scientists routinely build quantitative models — of, say, the weather or an epidemic — and then use them to make predictions, which they can then test against the real thing. This work can reveal how well we understand complex phenomena, and also dictate where research should go next. In recent years, the remarkable successes of “black box” systems such as large language models suggest that it is sometimes possible to make successful predictions without knowing how something works at all. In this episode, noted statistician Emmanuel Candès and host Steven Strogatz discuss using statistics, data science and AI in the study of everything from college admissions to election forecasting to drug discovery.
The “species” category is almost certainly the best known of all the taxonomic classifications that biologists use to organize life’s vast diversity. It’s a linchpin of both conservation policy and evolutionary theory, though in practice biologists have struggled to find a definition that works across the natural world. In this episode, Kevin de Queiroz, a zoologist and evolutionary biologist, talks with host Janna Levin about the variety of ways to conceive of a species, and ways to understand the relationships among living things.
When we think about medicine’s war on cancer, treatments such as surgery, radiation and chemotherapy spring to mind first. Now there is another potential weapon for defeating tumors: statistics and mathematical models that can optimize the selection, combination or timing of treatment. Building and feeding these models requires accounting for the complexity of the body, and recognizing that cancer cells are constantly evolving. In this episode, host Steven Strogatz hears from Franziska Michor, a computational biologist, about how our understanding of evolutionary dynamics is being used to devise new anticancer therapies.
If instruments do someday detect evidence of life beyond Earth, whether it’s in this solar system or in the farther reaches of space, astrobiologists want to be ready. One of the best ways to learn how alien life might function can be to study the organisms called extremophiles, which live in incredibly challenging environments on or in the Earth. In this episode, Penelope Boston https://astrobiology.nasa.gov/nai/directory/boston-penelope/, a microbiologist who has worked for many years with NASA, speaks with Janna Levin https://barnard.edu/profiles/janna-levin about the bizarre life found in habitats such as caves, how it would be possible to detect life beyond our solar system and what it would mean for humanity if we do.
The principles of thermodynamics are cornerstones of our understanding of physics. But they were discovered in the era of steam-driven technology, long before anyone dreamed of quantum mechanics. In this episode, the theoretical physicist Nicole Yunger Halpern https://quics.umd.edu/people/nicole-yunger-halpern talks to host Steven Strogatz https://math.cornell.edu/steven-strogatz about how physicists today are reinterpreting concepts such as work, energy and information for a quantum world.
Observations of the cosmos suggest that unseen sources of gravity — dark matter — tug at the stars in galaxies, while another mysterious force — dark energy — drives the universe to expand at an ever-increasing rate. The evidence for both of them, however, hinges on assumptions that gravity works the same way at all scales. What if that’s not true? In this episode, theoretical physicist Claudia de Rham explains her work on an alternative explanation called “massive gravity” to host Janna Levin.
Within just a few years, artificial intelligence systems that sometimes seem to display almost human characteristics have gone from science fiction to apps on your phone. But there’s another AI-influenced frontier that is developing rapidly and remains untamed: robotics. Can the technologies that have helped computers get smarter now bring similar improvements to the robots that will work alongside us? In this episode, Daniela Rus https://www.csail.mit.edu/person/daniela-rus, a pioneering roboticist at the Massachusetts Institute of Technology, talks to host Steven Strogatz https://math.cornell.edu/steven-strogatz about the surprising inspirations from biology that may help robots rise to new levels.
Can you keep a secret? Modern techniques for maintaining the confidentiality of information are based on mathematical problems that are inherently too difficult for anyone to solve without the right hints. Yet what does that mean when quantum computers capable of solving many problems astronomically faster are on the horizon? In this episode, host Janna Levin https://barnard.edu/profiles/janna-levin talks with computer scientist Boaz Barak about the cryptographic techniques that keep information confidential, and why “security through mathematics” beats “security through obscurity.” Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
Ask a question of ChatGPT and other, similar chatbots and there’s a good chance you’ll be impressed at how adeptly it comes up with a good answer — unless it spits out unrealistic nonsense instead. Part of what’s mystifying about these kinds of machine learning systems is that they are fundamentally black boxes. No one knows precisely how they arrive at the answers that they do. Given that mystery, is it possible that these systems in some way truly understand the world and the questions they answer? In this episode, the computer scientist Yejin Choi https://homes.cs.washington.edu/~yejin/ of the University of Washington and host Steven Strogatz https://math.cornell.edu/steven-strogatz discuss the capabilities and limitations of chatbots and the large language models, or LLMs, on which they are built. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
In the tiling of wallpaper and bathroom floors, collective repeated patterns often emerge. Mathematicians have long tried to find a tiling shape that never repeats in this way. In 2023, they lauded an unexpected amateur victor. That discovery of the elusive aperiodic monotile propelled the field into new dimensions. The study of tessellation is much more than a fun thought exercise: Peculiar, rare tiling formations can sometimes seem to tell us something about the natural world, from the structure of minerals to the organization of the cosmos. In this episode, Janna Levin https://barnard.edu/profiles/janna-levin speaks with mathematician Natalie Priebe Frank https://www.vassar.edu/faculty/nafrank about these complex geometric combinations, and where they may pop up unexpectedly. Specifically, they explore her research into quasicrystals — crystals that, like aperiodic tiles, enigmatically resist structural uniformity.. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
The universe seems like it should be unfathomably complex. How then is science able to crack fundamental questions about nature and life? Scientists and philosophers alike have often commented on the “unreasonable” success of mathematics at describing the universe. That success has helped science probe some profound mysteries — but as the physicist Nigel Goldenfeld https://guava.physics.uiuc.edu/~nigel/ points out, it also helps that the “hard” physical sciences, where this progress is most evident, are in major ways simpler than the “soft” biological sciences. In this episode, Goldenfeld speaks with co-host Steven Strogatz https://math.cornell.edu/steven-strogatz about the scientific importance of asking the right questions at the right time. They also discuss the mysterious effects of “emergence,” the phenomenon that allows new properties to arise in systems at different scales, imposing unexpected order on cosmic complexity. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
During traumatic periods and their aftermath, our brains can fall into habitual ways of thinking that may be helpful in the short run but become maladaptive years later. For the brain to readjust to new situations later in life, it needs to be restored to the malleable state it was in when the habits first formed. That is exactly what Gül Dölen, a neuroscientist and psychiatric researcher at the University of California, Berkeley, is working toward in her lab. What is her surprising tool? Psychedelics. In this episode, Dölen shares with co-host Janna Levin the surprising potential of psychedelics to change the lives of those grappling with addiction, depression and post-traumatic stress. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
For decades, the best drug therapies for treating depression, like SSRIs, have been based on the idea that depressed brains don’t have enough of the neurotransmitter serotonin. Yet for almost as long, it’s been clear that simplistic theory is wrong. Recent research into the true causes of depression is finding clues in other neurotransmitters and the realization that the brain is much more adaptable than scientists once imagined. Treatments for depression are being reinvented by drugs like ketamine that can help regrow synapses, which can in turn restore the right brain chemistry and improve whole body health. In this episode, John Krystal https://medicine.yale.edu/profile/john-krystal/, a neuropharmacologist at the Yale School of Medicine, shares the new findings in mental health research that are revolutionizing psychiatric medication. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
If superconductors — materials that conduct electricity without any resistance — worked at temperatures and pressures close to what we would consider normal, they would be world-changing. They could dramatically amplify power grids, levitate high-speed trains and enable more affordable medical technologies. For more than a century, physicists have tinkered with different compounds and environmental conditions in pursuit of this elusive property, but while success has sometimes been claimed, the reports were always debunked or withdrawn. What makes this challenge so tricky? In this episode, Siddharth Shanker Saxena https://www.phy.cam.ac.uk/directory/dr-siddharth-s-saxena, a condensed-matter physicist at the University of Cambridge, gives co-host Janna Levin https://barnard.edu/profiles/janna-levin the details about why high-temperature superconductors remain so stubbornly out of reach.. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
Milk is more than just a food for babies. Breast milk has evolved to deliver thousands of diverse molecules including growth factors, hormones and antibodies, as well as microbes. Elizabeth Johnson, a molecular nutritionist at Cornell University, studies the effects of infants’ diet on the gut microbiome. These studies could hold clues to hard questions in public health for children and adults alike. In this episode of “The Joy of Why” podcast, co-host Steven Strogatz interviews Johnson about the microbial components that make breast milk one of the most wondrous biofluids found in nature. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
Nothing escapes a black hole … or does it? In the 1970s, the physicist Stephen Hawking described a subtle process by which black holes can “evaporate,” with some particles evading gravitational oblivion. That phenomenon, now dubbed Hawking radiation, seems at odds with general relativity, and it raises an even weirder question: If particles can escape, do they preserve any information about the matter that was obliterated? Leonard Susskind https://sitp.stanford.edu/people/leonard-susskind, a physicist at Stanford University, found himself at odds with Hawking over the answer. In this episode, co-host Janna Levin https://barnard.edu/profiles/janna-levin speaks with Susskind about the “black hole war” that ensued and the powerful scientific lessons to be drawn from one of the most famous paradoxes in physics. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
Birds flock. Locusts swarm. Fish school. Within assemblies of organisms that seem as though they could get chaotic, order somehow emerges. The collective behaviors of animals differ in their details from one species to another, but they largely adhere to principles of collective motion that physicists have worked out over centuries. Now, using technologies that only recently became available, researchers have been able to study these patterns of behavior more closely than ever before. In this episode, the evolutionary ecologist Iain Couzin https://www.ab.mpg.de/person/98158/2736 talks with co-host Steven Strogatz https://math.cornell.edu/steven-strogatz about how and why animals exhibit collective behaviors, flocking as a form of biological computation, and some of the hidden fitness advantages of living as part of a self-organized group rather than as an individual. They also discuss how an improved understanding of swarming pests such as locusts could help to protect global food security. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, Google Podcasts https://podcasts.google.com/feed/aHR0cHM6Ly9hcGkucXVhbnRhbWFnYXppbmUub3JnL2ZlZWQvdGhlLWpveS1vZi13aHk, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
Quantum teleportation isn’t just science fiction; it’s entirely real and happening in laboratories today. But teleporting quantum particles and information is a far cry from beaming people through space. In some ways, it’s even more astonishing. John Preskill http://theory.caltech.edu/~preskill/, a theoretical physicist at the California Institute of Technology, is one of the leading theoreticians of quantum computing and information. In this episode, co-host Janna Levin https://barnard.edu/profiles/janna-levin interviews him about entanglement, teleporting bits from coast to coast, and the revolutionary promise of quantum technology. Listen on Apple Podcasts https://podcasts.apple.com/us/podcast/the-joy-of-why/id1608948873, Spotify https://open.spotify.com/show/2FoxHraQSKwxV2HgUfwLMp, Google Podcasts https://podcasts.google.com/feed/aHR0cHM6Ly9hcGkucXVhbnRhbWFnYXppbmUub3JnL2ZlZWQvdGhlLWpveS1vZi13aHk, TuneIn https://tunein.com/podcasts/Science-Podcasts/The-Joy-of-Why-p1653040/ or your favorite podcasting app, or you can stream it from https://www.quantamagazine.org/tag/the-joy-of-why.
Time seems linear to us: We remember the past, experience the present and predict the future, moving consecutively from one moment to the next. But why is it that way, and could time ultimately be a kind of illusion? In this episode, the Nobel Prize-winning physicist Frank Wilczek https://physics.mit.edu/faculty/frank-wilczek/ speaks with host Steven Strogatz https://math.cornell.edu/steven-strogatz about the many “arrows” of time and why most of them seem irreversible, the essence of what a clock is, how Einstein changed our definition of time, and the unexpected connection between time and our notions of what dark matter might be.
We often talk about evolution in terms of competition, as the survival of the fittest. But if it is, then where did the widespread (and widely admired) impulse to help others even at great cost to ourselves come from? In this episode, Stephanie Preston https://lsa.umich.edu/psych/people/faculty/prestos.html, a professor of psychology and head of the Ecological Neuroscience Lab at the University of Michigan, talks about the evolutionary, neurological and behavioral foundations for altruism with our new co-host, the astrophysicist and author Janna Levin https://barnard.edu/profiles/janna-levin.
We tend to think of mathematics as purely logical, but the teaching of math, its usefulness and its workings are packed with nuance. So what is “good” mathematics? In 2007, the mathematician Terence Tao wrote an essay for the “Bulletin of the American Mathematical Society” that sought to answer this question. Today, as the recipient of a Fields Medal, a Breakthrough Prize in Mathematics and a MacArthur Fellowship, Tao is among the most prolific mathematicians alive. In this episode, he joins Steven Strogatz to revisit the makings of good mathematics.
Aristotle argued almost 2,400 years ago that a perfect vacuum could never exist. Today, the concept of nothingness figures at least implicitly into almost every theory of modern physics. In this episode, the theoretical physicist Isabel Garcia Garcia https://www.ias.edu/scholars/isabel-garcia-garcia of New York University and the Institute for Advanced Study talks with host Steven Strogatz about the impact of quantum mechanics on the definition of a “true vacuum,” the possibility of false vacuums, how the concept of vacuum energy relates to the cosmological constant, and how her studies of the vacuum could help to resolve frustrating puzzles in string theory and cosmology.
The heart’s electrical system keeps all its muscle cells beating in sync. A hard whack to the chest at the wrong moment, however, can set up unruly waves of abnormal electrical excitation that are potentially deadly. The resulting kind of arrhythmia may be what caused the football player Damar Hamlin https://www.buffalobills.com/team/players-roster/damar-hamlin/ of the Buffalo Bills to collapse on the field after he took a powerful hit during a 2023 National Football League game. Today, powerful defibrillators are usually used to help resynchronize hearts in distress. But Flavio Fenton https://research.gatech.edu/flavio-fenton, who studies the electrical dynamics of the heart, tells Steve Strogatz about a new method under development for treating arrhythmias by stimulating the heart with mild, precisely timed shocks — or possibly even with light.
The jellyfish that move through the seas by gently pulsing their saclike bodies may not seem to hold many secrets that would interest human engineers. But simple as the creatures are, jellyfish are masterful at harnessing and controlling the flow of the water around them, sometimes with surprising efficiency. As such, they embody sophisticated solutions to problems in fluid dynamics that engineers, mathematicians and other professionals can learn from. John Dabiri https://dabirilab.com/dabiri, an expert in mechanical and aerospace engineering at the California Institute of Technology, talk with Steven Strogatz in this episode about what jellyfish and other aquatic creatures can teach us about submarine design, the optimal placement of wind turbines, and healthy human hearts.
Sailors have spun yarns for centuries about gigantic rogue waves that could suddenly come out of nowhere to capsize the ships of unwary mariners. Scientists didn’t believe them because the stories seemed at odds with everything else known about waves. Then cameras and other instruments began to capture undeniable proof of the existence of rogue waves. Ton van den Bremer, an expert in fluid mechanics, talks with Steven Strogatz about what science has learned about how rogue waves form, whether it’s possible to predict them and how the waves can be recreated in a lab.
* Neuroscience has made progress in deciphering how our brains think and perceive our surroundings, but a central feature of cognition is still deeply mysterious: namely, that many of our perceptions and thoughts are accompanied by the subjective experience of having them. Consciousness, the name we give to that experience, can’t yet be explained — but science is at least beginning to understand it. In this episode, the consciousness researcher Anil Seth https://profiles.sussex.ac.uk/p22981-anil-seth and host Steven Strogatz discuss why our perceptions can be described as a “controlled hallucination,” how consciousness played into the internet sensation known as “the dress,” and how people at home can help researchers catalog the full range of ways that we experience the world.
By definition, the universe seems like it should be the totality of everything that exists. Yet a variety of arguments emerging from cosmology, particle physics and quantum mechanics hint that there could also be unobservable universes beyond our own that follow different laws of nature. While the existence of a multiverse is speculative, for many physicists it represents a plausible explanation for some of the biggest mysteries in science. In this episode, Steven Strogatz explores the idea of a multiverse with the theoretical physicist David Kaplan https://physics-astronomy.jhu.edu/directory/david-kaplan/ and learns what it might mean about our own existence.
Perpetual motion machines are impossible, at least in our everyday world. But down at the level of quantum mechanics, the laws of thermodynamics don’t always apply in quite the same way. In 2021, after years of effort, physicists successfully demonstrated the reality of a “time crystal,” a new state of matter that is both stable and ever-changing without any input of energy. In this episode, Steven Strogatz discusses time crystals and their significance with the theoretical physicist Vedika Khemani https://sitp.stanford.edu/people/vedika-khemani of Stanford University, who co-discovered that they were possible and then helped to create one on a quantum computing platform.
