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The fundamental currency of our universe is energy.
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It lights our homes, grows our food,
powers our computers.
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We can get it lots of ways:
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Burning fossil fuels, splitting atoms,
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or sunlight striking photovoltaics.
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But there's a downside to everything
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Fossil fuels are extremely toxic,
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Nuclear waste is... well, nuclear waste,
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And, there are not enough batteries to store sunlight for cloudy days yet.
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And yet the sun seems to have virtually limitless free energy.
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Is there a way we could build a sun on Earth?
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Can we bottle a star?
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[Intro Jingle]
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The sun shines because of nuclear fusion.
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In a nutshell, fusion is a thermonuclear process.
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Meaning that the ingredients have to be incredibly hot.
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So hot, that the atoms are stripped of their electrons
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Making a plasma where nuclei and electrons bounce around freely.
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Since nuclei are all positively charged,
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They repel each other.
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In order to overcome this repulsion,
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The particles have to be going very, very fast
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In this context, very fast means "very hot"
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Millions of degrees
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Stars cheat to reach these temperatures.
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They are so massive, that the pressure in their cores
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Generates the heat to squeeze the nuclei together
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Until they merge and fuse
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Creating heavier nuclei and releasing energy in the process.
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It is this energy release that scientists hope to harness
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In a new generation of power plant,
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The fusion reactor.
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On earth it's not feasible to use this brute force method to create fusion.
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So if we wanted to build a reactor that generates energy from fusion,
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We have to get clever.
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To date, scientists have invented two ways of making plasmas hot enough to fuse:
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The first type of reactor uses a magnetic field to
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Squeeze a plasma in a doughnut shaped chamber
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Where the reactions take place.
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These magnetic confinement reactors
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Such as the I.T.E.R. reactor in France,
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Use superconducting electromagnets cooled with liquid helium
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To within a few degrees of absolute zero.
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Meaning that they host some of the biggest temperature gradients in the known universe.
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The second type called "Inertial confinement"
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Uses pulses from super-powered lasers
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To heat the surface of a pellet of fuel
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Imploding it, briefly making the fuel hot and dense enough to fuse.
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In fact, one of the of the most powerful lasers in the world
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Is used for fusion experiments
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At the National Ignition Facility in the U.S.
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These experiments and others like them around the world
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are today, just experiments.
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Scientists are still developing the technology,
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And although they can achieve fusion,
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Right now, it costs more energy to do the experiment
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Then they produce in fusion.
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The technology has a long way to go before it's commercially viable,
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and maybe it never will be.
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It might just be impossible to make a viable fusion reactor on earth,
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But if it gets there, it will be so efficient
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That a single glass of sea water, could be used to produce
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as much energy as burning a barrel of oil, with no waste to speak of.
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This is because fusion reactors
would use hydrogen or helium as fuel
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And sea water is loaded with hydrogen
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But not just any hydrogen will do.
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Specific isotopes with extra neutrons called Deuterium and Tritium
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Are needed to make the right reactions.
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Deuterium is stable and can be found in abundance in sea water,
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Though Tritium is a bit trickier.
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It's radioactive
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And there may only be 20 kilograms of it in the world
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Mostly in nuclear warheads
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Which makes it incredibly expensive.
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So we made need another fusion buddy for Deuterium instead of Tritium.
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Helium-3, an isotope of Helium,
might be a great substitute.
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Unfortunately, it's also incredibly rare on earth.
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But here, the moon might have the answer.
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Over billions of years, the solar wind may have built up huge deposits
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Of Helium-3 on the moon.
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Instead of making Helium-3, we can mine it.
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If we could sift the lunar dust for helium,
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We'd have enough fuel to power the entire world for thousands of years.
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One more argument for establishing a moon base, if you weren't convinced already.
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Ok, maybe you think building a mini sun
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Still sound kind of dangerous
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But they'd actually be much safer
than most other types of powerplants
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A fusion reactor is not like a nuclear plant,
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Which can melt down catastrophically.
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If the confinement failed, then the plasma would expand and cool,
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And the reaction would stop.
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Put simply, it's not a bomb.
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The release of radioactive fuel, like Tritium,
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Could pose a threat to the environment.
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Tritium could bond with oxygen making radioactive water,
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Which could be dangerous as it seeps into the environment.
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Fortunately, there's no more than a few grams in use at a given time,
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So a leak would be quickly diluted.
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So we've just told you that theres nearly unlimited energy to be had
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At no expense to the environment
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In something as simple as water.
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So, whats the catch?
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Cost. We simply don't know if fusion power will ever be commercially viable.
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Even if they work, they might be too expensive to ever build.
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The main drawback, is that it's unproven technology
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Its a 10 billion dollar gamble
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And that money might be better
spent on other clean energy
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That's already proven itself.
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Maybe we should cut out losses
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Or maybe, when the payoff is unlimited
clean energy for everyone,
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It might be worth the risk.
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Videos like this one take hundreds of hours to make
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and are made possible by your contributions on patreon.com
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If you want to learn more about global energy,
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Here's a playlist about nuclear energy, fracking and solar power.
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Let us know in the comments if there are other technologies you want us to explain.9498
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