What does it feel like to make one of the biggest discoveries in physics? Adam Riess knows — because his work revealed that the universe isn’t just expanding, it’s accelerating. In this episode, the Nobel Prize–winning astrophysicist takes us behind the scenes of the moment that changed cosmology forever. How did his team use exploding stars as “standard candles” to measure the cosmos? Why did the data point to a mysterious force now called dark energy, making up nearly 70% of the universe? And what’s behind today’s biggest cosmic puzzle: the Hubble tension? Plus, Adam shares what new telescopes could uncover — and why the next decade might rewrite the laws of physics all over again.   Learn more about NOVA and subscribe to our YouTube channel.  ————————— Guest Bio:  Adam Riess is an astrophysicist, professor at Johns Hopkins University, and a distinguished astronomer at Space Telescope Science Institute. In 2011, he was named as a co-winner of the Nobel Prize in Physics for his contributions to the discovery that the expansion rate of the universe is accelerating. Since then, he has continued refining measurements of cosmic expansion and the Hubble constant, aiming to find and measure the most distant type Ia supernovae known, to probe the origin of cosmic acceleration. Timestamps (00:00:00) Introduction (00:03:16) What Is a Type Ia Supernova?  (00:10:52) The Discovery of Dark Energy (00:44:39) What Is the Hubble Tension? (00:58:59) Winning a Nobel Prize (01:15:32) Credits

The universe isn’t adding up—and it’s creating a crisis in cosmology. Nobel Prize winner Adam Riess explains why measurements of the universe’s expansion rate from its earliest light and from nearby galaxies don’t match, and how this growing gap threatens the foundations of our standard model of the cosmos. Learn more about NOVA and subscribe to our YouTube channel. 

Discovering dark energy wasn’t just thrilling—it was terrifying. Nobel Prize Winner Adam Riess explains the nerve-wracking process behind confirming that the universe’s expansion is accelerating and why Einstein’s so-called “biggest blunder” turned out to be anything but. Learn more about NOVA and subscribe to our YouTube channel. 

Fame can hijack the brain like a drug—activating the same reward circuits that fuel a relentless chase for dopamine highs. Neuroscientist Heather Berlin reveals the antidote—and why even social media fame can trigger this cycle. For more, check out the extended interview with Heather Berlin. Learn more about NOVA and subscribe to our YouTube channel. 

Fossilization isn’t luck - it’s geology. Paleobotanist Kirk Johnson explains how fossils only form in certain conditions, the tricks to finding them, and why one fossil leaf can lead to thousands more.  For more, check out the extended interview with Kirk Johnson. Learn more about NOVA and subscribe to our YouTube channel. 

Speech is rare in the animal kingdom because it requires a very specific brain architecture. Neuroscientist Erich Jarvis explains how duplicating neural pathways for movement unlocked language, dancing, and even advanced problem-solving in more than just humans. For more, check out the extended interview with Erich Jarvis.  Learn more about NOVA and subscribe to our YouTube channel. 

How does evolution invent entirely new things, like limbs, wings, and venom? Evolutionary biologist Sean B. Carroll joins us to reveal the hidden rules behind nature’s creativity and the genetic toolkit that makes it possible. Carroll explains how the same set of genes can build wildly different creatures — from fruit flies to lobsters — simply by rewiring their genetic circuits. Discover why developmental biology holds the key to understanding evolution, how snake venom evolved, and why medicines like GLP-1 drugs and statins trace their origins to nature’s own innovations. Plus, what the emergence of new species tells us about life’s future and the surprising power of evolution to repurpose old parts in new ways.  Learn more about NOVA and subscribe to our YouTube channel.  ————————— Guest Bio:  Sean B. Carroll is a renowned evolutionary biologist and author whose work has inspired a deeper public understanding of evolution and the natural world. He is an Investigator at Howard Hughes Medical Institute (HHMI), where he was formerly Head of HHMI Tangled Bank Studios, and led the Department of Science Education from 2010-2023. He is also a Professor of Biology at the University of Maryland. His research focuses on genes that influence the evolution of animal diversity. Timestamps (00:00:00) How Does A New Species Evolve? (00:12:54) The Process of Speciation: Use It or Lose It (00:36:22) Development: What the Fruit Fly Taught Us (00:55:37) The Evolution of Defense Mechanisms & Developing Medications (01:19:55) The Role of Chance in Evolution (01:24:22) Credits

From legs on heads to missing eyes, fruit fly mutations exposed the genetic toolkit that builds all animals. Evolutionary Biologist Sean B. Carroll shows how these discoveries rewrote our understanding of evolution. Learn more about NOVA and subscribe to our YouTube channel. 

From snakes to jellyfish, venom is one of evolution’s most lethal inventions. Evolutionary Biologist Sean B. Carroll reveals how this deadly innovation emerged—and the new science behind antivenom inspired by nature’s own defenses. Learn more about NOVA and subscribe to our YouTube channel. 

The edge of a black hole isn’t what you think. Astrophysicist Janna Levin dives into the event horizon, the one-way transition where space and time warp so much that escape becomes as impossible as reversing the clock. For more, check out the extended interview with Janna Levin. Learn more about NOVA and subscribe to our YouTube channel. 

There’s no single ‘smoking gun’ for life beyond Earth. Microbiologist Peter Girguis explains the subtle fingerprints scientists hunt for—and why finding them on Mars could change everything. For more, check out the extended interview with Peter Girguis. Learn more about NOVA and subscribe to our YouTube channel. 

Scientists are editing genes for human speech into mice to see if they can learn vocal patterns. Neuroscientist Erich Jarvis explains how this could unlock not just speech—but entirely new ways of thinking. For more, check out the extended interview with Erich Jarvis.  Learn more about NOVA and subscribe to our YouTube channel. 

Can we bring extinct species back to life? Evolutionary biologist Beth Shapiro claims we just did. As Chief Science Officer at Colossal, her team made headlines in spring 2025 with the announcement of the de-extinction of the dire wolf. She takes us behind the headlines to explain how this is no “Jurassic Park” fantasy. She breaks down exactly how her team used ancient DNA, CRISPR genome editing, and the genomes of modern relatives to bring back lost traits and create animals capable of thriving in today’s ecosystems. Along the way, she dives into the surprising challenges of this work — from the quest for artificial wombs to the ethics of genetic engineering — and reveals how the same tools powering de-extinction are already helping endangered species survive.  Learn more about NOVA and subscribe to our YouTube channel.  ————————— Guest Bio:  Beth Shapiro is an evolutionary biologist and Chief Science Officer at Colossal, a company notably responsible for the de-extinction of  the dire wolf. She is also a professor of Ecology and Evolutionary Biology at UC Santa Cruz. Her research focuses on species evolution and the continued impact of human activities, considering questions about domestication, speciation and pathogen evolution. She is also exploring techniques to recover trace amounts of DNA from samples and the possible role of genomic technologies in the fields of conservation and medicine. Timestamps (00:00) What is De-Extinction? Reviving the Dire Wolf (29:45) Ethics and Backlash for Cloning  (38:10) Modifying DNA to Bring Species Back to Life (45:31) The Future of De-Extinction (54:30) Credits

Jurassic Park got it all wrong. Beth Shapiro would know… she’s Chief Science Officer at Colossal, the genetic engineering company that recently made headlines for bringing back the extinct dire wolf. She breaks down how de-extinction is really done, and why Jurassic Park can never happen. Learn more about NOVA and subscribe to our YouTube channel. 

The deepfake game is getting real. Deepfake detective Hany Farid gets under the hood of AI and explains exactly how it can now make such convincing fake content –  so convincing that he himself has trouble identifying his own real voice from an AI-generated fraud. Can you spot the deepfake? For more, check out the extended interview with Hany Farid. Learn more about NOVA and subscribe to our YouTube channel. 

Ever wonder why you get déjà vu? Or why you keep losing your keys? Your brain does some weird stuff. Neuroscientist Heather Berlin explains the surprising science behind these everyday mysteries. For more, check out the extended interview with Heather Berlin. Learn more about NOVA and subscribe to our YouTube channel. 

Space itself rings with gravitational waves when black holes collide—the most powerful events detected since the Big Bang. Astrophysicist Janna Levin reveals why, when the cosmic symphony fades, the merged black hole is stripped to flawless simplicity. For more, check out the extended interview with Janna Levin. Learn more about NOVA and subscribe to our YouTube channel. 

Could a Martian rock hold the most promising sign of life beyond Earth? Microbiologist Peter Girguis unpacks NASA’s stunning discovery of ‘leopard spots’ on a rock from Mars’s Jezero Crater—and why they look eerily like the handiwork of microbes on our own planet. For more, check out the extended interview with Peter Girguis. Learn more about NOVA and subscribe to our YouTube channel. 

A sinkhole can become a time capsule full of skeletons - layers upon layers of beasts that once walked the Earth - and Florida’s landscape is full of them. Discover the surprising science of how Florida’s sinkholes form, what they really are, and what can be found inside them. Come along with Dr. Kirk Johnson, Sant Director of the Smithsonian Institution National Museum of Natural History, as he describes what he calls "the best sinkhole experience For more, check out the extended interview with Kirk Johnson. Learn more about NOVA and subscribe to our YouTube channel. 

In a world flooded with fake videos and voice recordings that seem real, how can you detect deepfakes? Turns out, there are some aspects of the physical world that are not yet known to artificial intelligence - and those gaps are the key. Expert Hany Farid reveals techniques that can be used to detect AI-generated media. For more, check out the extended interview with Hany Farid.  Learn more about NOVA and subscribe to our YouTube channel.