I'd like to take a few minutes to explain why yesterday's news from the National Ignition Facility (NIF) in Livermore, CA, was such a big deal — and why it also wasn't.
What I don't want to do is suggest I'm an expert in nuclear physics. No, I'm a geek with a lifelong affection for astronomy and hard science fiction, so this blog entry required interesting research. In many a Golden Age SF novel, sleek, reflective rocket ships powered by atomic fusion reactors plied the vasty spaceways, so I was already somewhat familiar with the idea but had a lot to learn about the mechanics of making it work. As of yesterday, the technology of artificially generated nuclear fusion left the realm of science fiction and entered science fact. I wouldn't book your passage on a fusion-powered flight to Ganymede just yet, though.
First, a catch-up lesson for folks who snoozed through high school physics: You're probably familiar with the Einsteinian equation E = mc2, but may never have thought through its implications. What it basically means is energy can be turned into mass, meaning stuff, or vice versa. The E on one side of the equal sign is energy, the m is mass, and c represents the speed of light. The lack of punctuation between the m and c2 means those two quantities are to be multiplied. Light is extremely fast, so the speed of light is a very large number, and multiplying that number by itself (squaring it, hence the superscript 2) yields an absolute whopper of a number. It follows then, that a relatively small amount of mass can be made to yield a very large energy release, as was demonstrated for the first time near Socorro, NM, on 16 July 1945 in the form of a mushroom cloud. About six kilos of uranium yielded a 21-metric-kiloton blast. The point is, messing with something even as small as an atom can lead to an enormous burst of energy, which in turn can be either constructive or, as has all too often been the case, horrifyingly destructive.
In theory, there are two ways to mess with atomic mass and convert it into energy. Both take advantage of the equal sign in Einstein's equation. The first, which was used in the 1945 Trinity device and in reactors and so-called atomic bombs since, is fission. That's when you take a very large atom, uranium or plutonium for example, and rip it into pieces. Those fragments partly reassemble themselves into materials made of smaller atoms, but the remainder is converted into energy. Blammo! Atomic fission energy is actually safer in many ways than our usual methods of burning matter from things that used to be alive. Our ecosystem is reeling from the effects of burning hydrocarbons and releasing the resulting carbon into the atmosphere. Of course, that's not to say atomic fission energy for civilian use is entirely safe; witness the terrifying accidents at Chernobyl and Three Mile Island among others.
Then there's the other way, which is nuclear fusion. That's when you take two very small atoms, most often hydrogen, and smash them together at such high speeds that they're squished into the single configuration of a somewhat larger atom like helium. Not all the hydrogen stuff gets used in the helium recipe, and the rest of that matter gets converted into energy. That's the exact mechanism used by so-called hydrogen bombs, the sun and most stars. For billions of years now, the sun has been blazing away in a continuous fusion reaction, with hydrogen falling into its center and getting smooshed into helium and energy.
Now, obviously that creates very high temperatures, but that mega-degree heat can be used to boil water, which in turn creates steam, which can push a turbine around and around, and that turbine can generate electricity and now you have power for stuff like lighting and air conditioning and 4K Disney+. One advantage of fusion is it doesn't create greenhouse gases or radioactive byproducts. A disadvantage was, until yesterday, it cost more energy to jump-start nuclear fusion on earth than was gained coming out of it.
That sort of changed yesterday, sort of, when scientists aimed 192 carefully calibrated lasers at a golden canister about the size of a pencil eraser. Inside was an industrial-diamond sphere the size of a peppercorn, which in turn contained two varieties of hydrogen. When the lasers hit the canister, the gold superheated to millions of degrees, and that blasted X-rays into the canister's interior. Those X-rays in turn imploded the capsule, which triggered nuclear fusion of the hydrogen into helium. The laser trick shot lasted less than a hundred trillionths of one second, but it made scientific history because while the lasers shot two megajoules of energy, roughly the energy in two sticks of dynamite, the resulting fusion released about three megajoules of energy. News media were quick to assure us that meant inexpensive clean energy was now in the making.
Well, it isn't quite that simple. See, actually running and firing those 192 lasers required hundreds of megajoules of energy, and the heat they released, once converted to electricity, would run a single light bulb for a handful of minutes. I mean, whoopity-doo. Gold and diamond are a great deal harder to come by than hydrogen (which is, after all, the H ingredient in the familiar recipe for water, H2O), and once they were gone, that was it for this particular fusion reaction. To create useful power, you'd need to create similar reactions several million times a day. Happily, that means there's zero risk of a runaway chain reaction in 2022 or probably ever, but it also means we have a long way to go before anyone figures out how to turn nuclear fusion into electricity enough to run global civilization. Most experts think it'll be at least 15 to 20 years before fusion power plants are ready to go online. When they do, though? Hoo, boy. It'll drastically cut our need for fossil fuels and will help us turn the tide on global warming, which would be nothing short of a terrestrial game changer. Together with wind and solar power, we could finally have an ecologically friendly yet electricity-gobbling society straight out of Star Trek.
Oh, and make no mistake about it: Some country, perhaps some corporation, will get very, very, mega, obscenely rich in the process. As an American, I'm glad we're on the forefront of this technology. As a humanist and futurist, I sincerely hope it'll be safely but generously shared with the world.
P.S. Dec. 15: I edited this post for accuracy regarding nuclear weapons, with gratitude to commenter Alan Marshall.