NOVA Presents

Why Dark Matter Matters

NOVA Presents

Show Notes

David Kaiser knows the universe is hiding something enormous – and no one can see it. Dark matter appears to be all over our universe, but what is it? As a physicist and science historian, David joins Hakeem to discuss one of astrophysics most impossible puzzles. Nearly a century of observations - from the motion of galaxy clusters to the rotation of individual galaxies to the subtle patterns in the cosmic microwave background - has built a remarkably consistent case that most of the matter in the universe is invisible to us. Kaiser and Hakeem work through how that evidence accumulated, why the leading candidate explanations have become increasingly constrained, and one tantalizing idea that is getting physicists excited. Make sure to subscribe now so you never miss an episode. Learn more about NOVA and visit YouTube channel. -------------------------- Guest Bio: David Kaiser is a professor of physics and the history of science at MIT. His research spans the history of modern physics, cosmology, and the foundations of quantum theory. He is the author of several books, including How the Hippies Saved Physics, and is a frequent contributor to public conversations about science and its history.

More from NOVA Presents

Oct 22, 2026

Earthquakes can be more powerful than atomic bombs. Luckily, Harvard geophysicist John Shaw has ideas on how to beat them. What really causes earthquakes? How can cities and buildings be engineered to survive them? John and Hakeem trace the science of shaking ground from ancient myth to cutting-edge machine learning, and reveal just how much is still left to discover deep beneath the surface. Learn more about NOVA and visit our YouTube channel. -------------------------- Guest Bio: John Shaw is the Harry C. Dudley Professor of Structural and Economic Geology at Harvard University, where he also serves as Vice Provost for Research. A structural geologist and applied geophysicist, he studies the faults deep beneath our feet, with research spanning earthquake hazards, energy systems, and carbon storage.

Oct 20, 2026

We can cause earthquakes. Geophysicist John Shaw joins Hakeem to reveal how humans have been triggering earthquakes for decades, and in some cases, it’s on purpose. John explains how an experiment 50 years ago turned earthquakes on and off and clarifies all the confusion around the process of fracking. It's a surprising look at how understanding human-triggered quakes might be the key to predicting natural ones. Learn more about NOVA and visit our YouTube channel. -------------------------- Guest Bio: John Shaw is the Harry C. Dudley Professor of Structural and Economic Geology at Harvard University, where he also serves as Vice Provost for Research. A structural geologist and applied geophysicist, he studies the faults deep beneath our feet, with research spanning earthquake hazards, energy systems, and carbon storage.

Oct 15, 2026

We can’t predict earthquakes, but we can beat them. Geophysicist breaks down what actually keeps people alive when the ground starts shaking. From flexible buildings to early warning systems, John walks Hakeem through what separates cities that survive major earthquakes from cities devastated by them, and why the difference often comes down to policy not physics.

Oct 13, 2026

Big earthquakes can change the Earth’s rotation. And Harvard geophysicist John Shaw says these giant events can teach us a lot. He traces our understanding from ancient myths to modern studies and unpacks what;s really going on beneath the surface. John reveals why a magnitude 7 earthquake releases 30 times the energy of a WWII-era atomic bomb, how the largest quakes make the Earth ring like a bell for days, and why the deadliest earthquake in history wasn't even the biggest one.

Oct 8, 2026

There is a near-limitless energy source to power our world, and it may be almost here. Dennis Whyte shares with Hakeem that we're closer than ever to bottling the power of the sun. He would know. He’s now the CEO of the United Kingdom’s Atomic Energy Authority and a nuclear scientist at MIT. What happens when we finally unlock nuclear fusion, the same energy source that powers the sun? What even is fusion? How does it work, and why are scientists now so close to building commercially viable fusion systems that could put power on the grid? From fusion fundamentals, to the future of energy, to interstellar space travel, Dennis and Hakeem deliver a big conversation on an innovation that could change everything.

See all episodes →