Looking for a Feynman reference (re: P, C, and CP)

[Eye_in_the_Sky]

I remember reading a discussion by Feynman somewhere. He talks about parity and charge conjugation in terms of a hypothetical scenario involving "radio communication" with an alien civilization living far off in outer space.

I don't remember the name of book I read this in. Does anyone know what book it's in?

[jtolliver]

I've seen it before too. I think it's in "The Pleasure of Finding Things Out", but I'm not entirely sure.

[neutrino]

I've seen it before too. I think it's in "The Pleasure of Finding Things Out", but I'm not entirely sure.

Although I haven't read the book completely yet, I didn't find any reference to it in the index. A page from The LBL's site mention Feynman's idea...

http://www.lbl.gov/abc/wallchart/chapters/05/2.html

[ahrkron]

He probably used the analogy more than once. It is included for sure in one of the Feynman lectures. Probably in volume one, when he speaks about symmetries.

He is basically saying that, due to the violation of P in weak interactions, it would be possible to communicate what is "left" and "right" to an alien via radio. When finally meeting with the alien after having agreed to a right-hand-shake as a salutation, if he extends his left arm "watch out!!", since he is made of antimatter.

[jcsd]

I'm pretty sure it's Volume 1, I think it also appears in either six easy pieces or six not-so-easy pieces.

[robphy]

Yep. Chapter 52 in Vol I.

[Eye_in_the_Sky]

Thank you, all! :smile:

... Yes, I see it there in the "Feynman Lectures". The discussion begins in section 52-6 on page 52-8.

[I also briefly looked into "The Pleasure of Finding Things Out" (an edited transcript, published in 1999, of an interview with Feynman filmed in 1981). Using the search tools available at Amazon.com, it appears to me that in that interview no reference was made to this "story" of P, C, and CP.]