RENEE MONTAGNE, host:
The president is not the only politician you might be thinking about today. NPR's Robert Krulwich has been looking backward as well as forward and the word is: Beware.
ROBERT KRULWICH reporting:
I know it may have slipped your mind, so let me just mention that today is the 2050th anniversary of the death of Julius Caesar. Yep, this is the day, March 15--the Ides of March--44 B.C. He came to the Roman Senate. He got stabbed repeatedly. He cried out et tu brute--that's the Shakesperean version. He gasped his final breath and he died. Now to honor this even in a very personal way, first, I want you to meet Professor Dan Nocera.
Professor DAN NOCERA (Professor of Chemistry, Massachusetts Institute of Technology): I teach chemistry at MIT. I'm a professor of chemistry.
KRULWICH: And in your classes do you mention Caesar and his last breath?
Professor NOCERA: Yes, sometimes that's true. He is mentioned.
KRULWICH: And it's not just in Dan's class. It seems that Caesar's last breath is mentioned in chemistry classes all over the place.
Professor NOCERA: That's right. Caesar's last breath really caught on.
KRULWICH: Okay, let me tell our audience what you teach in class. When Caesar exhaled that final time, how many breath molecules did he exhale?
Professor NOCERA: Well, all you have to do is multiply .05 x 6 x 10 to the 23rd and that's how many you get, which is quite a bit.
KRULWICH: That's enormous! That's hundreds and hundreds of trillions of molecules. Now, what chemistry professors teach is that when anybody exhales, those molecules, once they leave you, will float free and spread across the globe in a mathematically predictable pattern. So, when Caesar exhales his molecules...
Professor NOCERA: Some are absorbed are plants.
Professor NOCERA: Some by animals who eat the plants.
KRULWICH: Some get absorbed by water.
Professor NOCERA: They go into the ocean.
KRULWICH: And the rest float free. They're floating right now in the air all over the globe.
Professor NOCERA: Yes.
KRULWICH: So, let me ask you now, Dan Nocera, if I take a deep breath (inhales), how many molecules that were in Julius Caesar's lungs when he exhaled in 44 B.C., how many of those same molecules did I just breathe in?
Professor NOCERA: You got about one.
KRULWICH: One. You mean one of Julius Caesar's molecules.
Professor NOCERA: You just had one molecule go into your lungs from Caesar.
KRULWICH: Now, do you mean this poetically, like kind of like one of his molecules, or do you mean that one of the molecules literally in Caesar's chest then, is now in my lungs--the actual molecule?
Professor NOCERA: Yep. It's in your lungs.
KRULWICH: Huh. Really.
Professor NOCERA: And now you just breathed it out, but you got another one on the next breath.
KRULWICH: This is real science? You really believe this?
Professor NOCERA: Yes I do.
KRULWICH: Which means--and this may not be the most hygienic thought in the world--that what Caesar and Cleopatra and Shakespeare and Lincoln--what they all breathed out, you breathe in.
Professor NOCERA: We have everybody.
KRULWICH: I know, but since this is Caesar's day, today if you want to, you know, commemorate, you want to share a moment with the old Roman guy, just breathe in (inhales) and share his molecule. Robert Krulwich, NPR News in New York (exhales).