Hey there, Stephen Dubner. A couple years ago, we made three-part series about the physicist Richard Feynman, and we heard from so many of you that we have decided to replay it now. This is part two.

We have updated facts and figures as necessary. The biggest update you'll want to keep in mind as you listen today is that both the Feynman family home and Zorthian ranch were destroyed in the LA wildfires last year.

As always, thanks for listening.

On July 16, 1945, a team of U.S. scientists based in Los Alamos, New Mexico, conducted what their leader, J. Robert Oppenheimer, had named the Trinity Test. They were detonating a new kind of bomb way out in the desert, a couple hundred miles from the secret lab at Los Alamos

where they had created it. The U.S. President, Harry Truman, seemed to fully grasp the magnitude

of this moment. It is an atomic bomb. It is a harnessing of the basic power of the universe.

Oppenheimer had put together a dream team of experienced physicists, many of them recent refugees from Nazi Germany.

Also, playing a minor but important role, was a 24-year-old physicist from Queens, New York, named Richard Feynman.

Years later, here is how Feynman described watching the Trinity test.

Okay, time comes, and this tremendous flash, so bright, and I see this purple splotch on the

floor of the truck, and I says, that ain't it.

That's an aftermath.

So I turn back up, and I see this white light changing into yellow and into orange.

The clouds form, and then they disappear again.

And then finally, a big ball of orange is a start at the rise and billow a little bit

and get a little bit black around the edges.

And then you see it's a big ball of smoke with flashes on the inside of the fire going out, the heat.

All this took about one minute.

Finally, after about a minute and a half, suddenly there's a tremendous noise, bang!

And then rumbles like thunder.

And that's what convinced me. Nobody had said a word during this whole minute.

We're all just watching quietly. But this sound released everybody because the solidity of the sound at that distance

...