Eric Weinstein

because everything is charged like with light.

But what if you have something that doesn't feel that charge, but it's just like a proton?

That's like a bullet that then taps this thing.

And this thing is already straining to stay together under the strong force.

So it blows apart.

And what does it do?

It releases more bullets, these neutrons.

And that's what a chain reaction is.

It's bullets creating bullets creating bullets, tapping at these, think about a bunch of magnets

velcroed together so that they stay together and don't repel.

And then suddenly when you tap them, the velcro comes apart because it's just that critical.

So that would be called a subcritical mass of heavy elements like uranium.

And now the idea is that if you push that together, it goes from subcritical, not enough bullets to start the chain reaction, to critical, enough bullets.

That's what causes the reaction.

So what you do is you take a subcritical mass of radioactive material,

and you wrap it in a sphere of chemical explosives, and you push that thing from subcritical to critical so that the density of the bullets means that there are enough targets for them to hit.

That's the first stage, and that's fission.

And that's what we did in Hiroshima and Nagasaki in 1945 and at Trinity.

Now, why did it take seven years to come up with thermonuclear weapons?

Because what you want to do there is you want to actually fuse hydrogen into helium to release the energy that you get in the sun.