you know, gang, the hang glider-- [laughing] thanks, paul. you know, paul casey is a science writer, you know, and he's taking our class? he writes--he makes his living writing science articles. anyway, anyway, gang-- is this, gang, we have to be patient of where we are in our history. everything doesn't happen at once. we're still growing, you know? now, with this fusion, how come we don't have fusion power plants? it's too hard to take these things and push them together. it's enormous electrical repulsion. if you'd heat this stuff up to a gas, maybe above a hundred million degrees, these things will be fast-- going fast enough, they'll scrunch. how does the sun and the stars do it? brute force, gravity. [makes sound] i say, "i don't care electrical repulsion, no electrical repulsion." wham. right in. and the sun and the stars is just brute force these things together, and you get your fusion. now, how do we get that-- how do we do that in earth? we've been trying brute force. with plasma reactors. heat these things up to over a hundred million degrees, get that gas, pinch it with magnetic fields. boom. try to get it defused. has the human race done that? yes, we've done that. have we had a sustained reaction?

no, we haven't had a sustained reaction. have we had any reaction to give off more energy than put in? no, we haven't. how come? our time has not yet come. we're trying different techniques. we're trying it out with lasers. what we do is take little pellets. drop them. you had this in the textbook. little pellets of hydrogen. take all these lasers-- [makes sound] --wham. brute force smash these things together. and that should work too. sustained reaction, more energy out than required to operate the lasers? begin with an n. no. why? it's not our time. kind of a loose way of putting it. and there's another way, too. they've done it altogether without brute force. and i'm talking about cold fusion. i'm not talking about the utah experiments that caused all this publicity in 1989. i'm talking about--1988, was it? 1988? 18-- 1989, yeah. i'm not talking about those reactions, which, of course, were sort of the more publicity stunt than anything else.

i'm talking about the cold fusion that's muon-induced. see, here's a problem with that. let's get into that just a little bit. let's suppose i got this proton over here, and i want to this proton to fuse into that. well, once i get beyond the electron here, there's gonna be an enormous repulsion. very, very tough to do. okay? because this positive charges repel. but what if this electron were replaced by another particle that behave like an electron but was much, much more massive and would orbit way down in here. there is such a particle, and it's called a mu-meson. and a mu-meson has the same charge of an electron, and it will orbit very, very close. now, when this proton is coming over here, is it repelled by this configuration? no, it is not because it sees a neutral charge. it's very, very close. and what happens if it succeeded in doing this? spinning mu-mesons into this hydrogen gas, and it'll take the place of the electron. and this thing will come right over and, boom, snap, fuses at room temperature almost.

and this is really, really neat. only one trouble. only one trouble. the mu-mesons are very, very short lived. they only last two billionths of a second. but you know what? they can get--it turns out when this thing reacts-- [makes sound] --it fires out-- it fires the mu-meson back, and that can hit another one, and another, and another-- they have more like--more than a hundred times in its lifetime, a mu-meson could make a reaction. this is very, very exciting. this is cold fusion. and they do it--it works best at about 900 degrees fahrenheit. very, very cool compared to anything else. so read about this in the text and watch for it. it's kind of like a contender. there are problems because these mu-mesons are hard to come by. it takes energy to get those. and so far, we have-- we can't see a way that we can get more energy out of the reaction than it takes to fire it up to begin with. so these are problems that the technician-types are working on now. the physics-types and the technology-types are working on. but when--and if and when they're solved, things are gonna be like different.

really different. questions? i didn't quite catch the deal on breeder reactors because, say, losing mass is the name of the game. redirectors make it. let's go to that very, very quickly. what a breeder reactor does is very simple. if in your reactor you have 238 of plutonium-- or 235 of plutonium causing the fusion, if you put in some u-238-- i erased it over here-- the 238 will be turned to plutonium. so you're really not gaining any mass. what you're doing is you're converting something that's not very helpful, 238. you're converting that to something that is very helpful, energy-wise, plutonium. and the analogy i used in the book is like putting gasoline-- putting some water in your gasoline in your car. so it isn't like you get more mass than you started with. you're just converting the water to the gasoline. or in this case, you're converting the 238 to plutonium.

and it turns out, every reactor is all the time breeding. if you have any 238 in there at all, it's gonna turn the plutonium. some of it's gonna do that. so all fusion reactors are, to some extent, breeder reactors. it's just whether or not, you designed your reactors, so that's a main feature or not. but if we chose to make a reactor with plutonium, wasn't that the--on this table or that's-- what i remember from my reading is that there's always a chance that a plutonium reactor might explode. so that's somewhat-- to my knowledge, that's not the danger, no more dangerous with the plutonium than 235. it's not a question of exploding. if the chernobyl reactor didn't explode, it overheated. to cause these things to explode, to make a bomb, you have to contain-- you have to have it contained and crushed together.

reactors won't explode. it won't blow up like a bomb. you wouldn't see like a hiroshima or a big cloud. no reactor will do that. what they'll do is they'll overheat. it will overheat and melt down. all this stuff will spew out and it gets into the environment. is that good or bad? beginning with a b. yeah. but it's not an explosion. yeah. now, this thing over here, this is not even-- you can't-- this is at low temperature, and it's sort of self-sustaining. this has no chance at all of being used as a weapon, which is kinda-- this is all in the textbook. the neat thing is if we get to the point, we have like a fusion age. and all this idea of getting oil and things like that for fuel, we have no more problem with energy. and how do we make matter? matter is made by what? fusing things together. and i think the day will come when human begins will do that. what's the world gonna be like when there's abundant energy and abundant materials? no more scarcities? it's gonna be different. now is that gonna be good or it will be bad? it's hard to say. but i think of one thing, i think of my own story when i was a kid.

i remember i used to-- i knew what i wanted to do. a lot of kids don't know what they wanna do when they grew up. i knew what i wanted to do. i had it all straighten there. i was gonna be an airplane pilot because i lived near--field. at--field, you see those guys there riding these little airplanes. they put their caps on and the glasses and everything. put their cigarettes right up in here, okay? remember that? and they fly up there, man. we climb the trees and kinda look out. you know, you kinda see far, but these guys up above-- these airplanes. wheew. that's where it's at. i knew i was gonna be an airplane pilot, but i had a hang-up, like most kids do. and my hang-up was is that i didn't know how to tie my shoes. and my sister used to humiliate me 'cause i couldn't tie my shoes, and she could. and she was younger than me. and i was afraid when i get to be an airplane pilot that my sister was gonna tell on me. and all those people would humiliate me, and i would be humiliated. and i really had a problem about that. how am i gonna fly these-- well, i have to get the kind of shoes that you don't have to tie, you know? and i was really, as a kid, worried about that. and i think in a similar way, we kind of worry about what the future's gonna be too. not realizing by the time the future comes,

honey, we'll be able to tie our shoes. we'll tie our shoes and do better than that. so when that future comes, we'll be ready for it. but a lot of changes, gang. think about these things. [music]