Stars have cores hot and dense enough to force atomic nuclei together, forming larger, heavier nuclei in a process known as fusion. In this process, the mass of the end products is slightly less than the mass of the initial atoms. But that “lost” mass doesn’t disappear — it’s converted to energy ... a lot of energy. So, can we harness this energy to power the world? George Zaidan investigates. This TED-Ed lesson was directed by Igor Ćorić, Artrake Studio, narrated by George Zaidan and the music is by Cem Misirlioglu and Brooks Ball.
Learn more about our flagship conference happening this April at attend.ted.com/podcast
Hosted on Acast. See acast.com/privacy for more information.
[00:00:00] Ted Audio Collective
[00:00:02] Nuclear fusion sounds like something out of a sci-fi novel.
[00:00:13] It's technology that promises to harness the power of the stars right here on Earth.
[00:00:18] But it's real. Scientists have been working on creating a miniature version of the sun's energy,
[00:00:24] using fusion to generate massive amounts of clean, nearly limitless power.
[00:00:30] The process is complex, but the goal is simple.
[00:00:33] To create a reactor that can power entire cities with minimal environmental impact.
[00:00:41] This is TED Tech, a podcast from the TED Audio Collective.
[00:00:46] I'm your host, Sherelle Dorsey.
[00:00:48] Today's TED-Ed lesson is all about, you guessed it, nuclear fusion.
[00:00:54] Imagine, two trucks of fusion fuel could replace the need for millions of tons of coal.
[00:01:01] Though we're still in the early stages, recent breakthroughs in ignition bring us closer to realizing this dream.
[00:01:09] Could fusion energy be the key to solving our energy crisis?
[00:01:13] Let's explore how this revolutionary technology might reshape our future.
[00:01:18] But before we dive in, a quick break to hear from our sponsors.
[00:01:35] How will humans and machines work together in the future?
[00:01:39] We spend so much time discussing how the world's changing.
[00:01:43] It would be absolutely absurd to believe the role of the CEO is not.
[00:01:47] This is Imagine This, a podcast from BCG that helps CEOs consider possible futures for our world and their businesses.
[00:01:56] Listen wherever you get your podcasts.
[00:02:02] What does the AI revolution mean for jobs, for getting things done?
[00:02:08] Who are the people creating this technology and what do they think?
[00:02:12] I'm Rana El-Kalubi, an AI scientist, entrepreneur, investor, and now host of the new podcast, Pioneers of AI.
[00:02:21] Think of it as your guide for all things AI with the most human issues at the center.
[00:02:27] Join me every Wednesday for Pioneers of AI.
[00:02:31] And don't forget to subscribe wherever you tune in.
[00:02:38] And now, listen to this TED-Ed episode, narrated by George Zayden.
[00:02:44] In the time it takes to snap your fingers, the sun releases enough energy to power our entire civilization for 4,500 years.
[00:02:52] So, naturally, scientists and engineers have been working to build a miniature star here on Earth to plug into our power grid.
[00:03:00] And the thing is, we already kind of have.
[00:03:04] It just doesn't look like a tiny star floating in a lab.
[00:03:07] Stars are made of an almost incomprehensible number of particles which gravity compresses into a super-dense core.
[00:03:14] This core is hot and dense enough to force atomic nuclei together, forming larger, heavier nuclei in a process known as fusion.
[00:03:23] The reverse process, where one atom splits into two, is called fission.
[00:03:28] In both processes, the mass of the end products is slightly less than the mass of the initial atoms.
[00:03:34] But that lost mass doesn't disappear.
[00:03:36] It's converted to energy according to Einstein's famous equation.
[00:03:40] And since C squared is such a massive number, both fission and fusion generate a lot of energy.
[00:03:47] Fusion in our sun mostly produces helium nuclei.
[00:03:51] In the most common pathway, two protons fuse to form a deuterium nucleus,
[00:03:55] which then fuses with another proton to form a helium-3 nucleus,
[00:04:00] which then fuses with another helium-3 nucleus to form a helium-4 nucleus.
[00:04:05] But there's a catch.
[00:04:06] That first step is incredibly rare.
[00:04:09] Only one in a hundred septillion collisions between protons results in a deuterium nucleus.
[00:04:15] In the sun, this isn't a problem because there are so many protons that even a reaction this rare happens all the time.
[00:04:22] But on Earth, researchers rely on a more easily reproducible reaction,
[00:04:27] where a deuterium nucleus fuses with a tritium nucleus to form a helium-4 nucleus and a neutron.
[00:04:33] We've actually been doing reactions like this one inside particle accelerators since the 1930s.
[00:04:40] But these accelerators are not designed to harness the energy this reaction releases.
[00:04:44] Rather, they're used to generate neutrons for a variety of scientific and military purposes.
[00:04:49] Whereas, if we want to use fusion to produce limitless energy,
[00:04:53] we'd need a device that can harness the energy released,
[00:04:56] channel enough of that energy back into the device to keep the reaction going,
[00:05:00] and then send the rest out to our power grid.
[00:05:03] And for that job, we need a nuclear fusion reactor.
[00:05:07] Like a particle accelerator, a reactor would generate helium nuclei and neutrons.
[00:05:12] But that reaction would happen in a super-hot core,
[00:05:15] and the resulting neutrons would shoot outward to heat up a layer of lithium metal.
[00:05:20] That heat would then boil water, generating steam to run turbines and produce electricity.
[00:05:25] Meanwhile, the helium nuclei would stay in the core
[00:05:28] and slam into other nuclei to keep the reaction going and the electricity flowing.
[00:05:33] This tech has many practical challenges,
[00:05:36] including how to confine a swirling mass of million-degree matter.
[00:05:40] But the biggest hurdle is achieving what's called ignition.
[00:05:43] An energy technology is only commercially viable if it puts out more energy than it uses,
[00:05:48] and a fusion reactor needs a lot of energy to get the core hot enough for fusion to occur.
[00:05:54] So there's a tipping point,
[00:05:55] a moment when the fuel is hot enough to start the reaction
[00:05:58] and release more energy than is needed to reach and maintain that temperature.
[00:06:03] This is ignition.
[00:06:05] Stars reach ignition under the force of huge amounts of gravity,
[00:06:08] but this approach is impossible on Earth
[00:06:10] since you'd need thousands of times the mass of, well, the entire Earth.
[00:06:15] So researchers typically rely on vast arrays of lasers
[00:06:18] or methods that combine magnets with high-energy particles
[00:06:22] or electromagnetic waves similar to those in your microwave oven.
[00:06:26] In 2022, scientists at the U.S. National Ignition Facility
[00:06:30] demonstrated ignition for the first time ever,
[00:06:33] using 192 lasers to heat deuterium and tritium to 100 million degrees.
[00:06:40] While this was a huge step forward,
[00:06:42] we're still a ways off from a self-sustaining,
[00:06:44] long-running reactor that produces more energy than it uses.
[00:06:48] But once operational,
[00:06:49] these relatively small reactors could power a city of a million people for a year
[00:06:54] with just two pickup trucks of fuel.
[00:06:56] Today, you'd have to burn roughly 3 million tons of coal
[00:07:00] to produce that much energy.
[00:07:02] That is the promise of fusion,
[00:07:05] limitless, on-demand energy with almost no emissions.
[00:07:09] True star power right here on Earth.
[00:07:11] And that's it for today.
[00:07:24] TED Tech is part of the TED Audio Collective.
[00:07:27] This episode was produced by Nina Bird Lawrence,
[00:07:30] edited by Alejandra Salazar,
[00:07:32] and fact-checked by Julia Dickerson.
[00:07:34] Special thanks to Maria Latias,
[00:07:36] Fer de Grange,
[00:07:37] Daniela Belarezo,
[00:07:38] and Roxanne Highlash.
[00:07:40] I'm Cheryl Dorsey.
[00:07:42] Thanks for listening.