Are We Breathing Caesar’s Last Breath

Are We Breathing Caesar’s Last Breath

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Hey folks, we’re helping PBS celebrate the
Great American Read! We sat down with Sam Kean to talk about his
book Caesar’s Last Breath and how the chemistry of atmospheric gases can be so darn interesting. The book explores the classic chemistry question:
are you breathing some of the same air molecules that were expelled by Julius Caesar’s dying
exhalation? It’s something you simply can’t work out
exactly without knowing a ton of data: Caesar’s exact lung capacity, the composition of the
air in ancient Rome, atmospheric circulation from March 15th, 44 BCE, to today and…stop,
stop, I’m getting a headache. Instead, you treat it as what we call a Fermi
problem. Physicist Enrico Fermi had a knack for working
out rough estimates that weren’t right, but close enough to give you a general idea. Using Fermi’s close-enough style of logic,
what do you get? “Are we breathing Caesar’s last breath?” “So, yes we are, actually, breathing…PARTS
of Caesar’s last breath.” “Each person, when you breathe, it’s about
a half a liter to a liter.” “In the book I mention the exact amount, but
it’s like a zero point nineteen zeroes, that’s the percentage that one breath is
compared to the entire atmosphere, so a minuscule amount.” “On the other hand, if you look at how many
molecules, gas molecules, are actually in a liter, at you know, room temperature, it’s
some gargantuan number, it’s like 25 sextillion, which is a 25 with 21 zeros after it. So it’s a huge, like an unfathomably large
number. “So the question becomes, well, which number’s
gonna win? The tiny number, which is how big a breath
is compared to the atmosphere, or the really BIG number, which is how many molecules are
in a single breath? And when you go through all the math, crunch
all the numbers, it turns out that they cancel almost exactly, and you end up with on average
about one molecule of Caesar breath in every breath that we take.” Fermi estimation is pretty fun, if you ask
me, because you can come up with answers you should in no way be able to find the answer
to — like whether you’re sharing air with Caesar. But why him? Why not Joan of Arc or Madame Curie or Tessa
Thompson? “He’s become for some reason the default
person that you hear with this problem, I dunno why someone fixated, I’m sure back
in the days when they were studying classics all the time…” “But even, you know, two to three years, the
atmosphere has enough turbulence, it mixes enough, where those molecules would be fairly evenly spread over the entire world. So yes, Shakespeare, Amelia Earhart,
Winston Churchill, Confucius, you have a connection with their breath as well.” But it turns out Caesar’s last words provided
enough inspiration for a whole book on what the atmosphere’s made of. “I think what I was a little surprised about
was just the variety of different gases that you do see in the atmosphere. You see, uh, refrigerants, you see little
bits of anesthesia, you see all the noble gases in there. Argon is roughly one percent of the atmosphere.” We’ve treated the atmosphere pretty badly,
what with all the climate change and the aforementioned refrigerants poking holes in the ozone layer
and all that stuff. Is there any good news? “There’s good news coming out about the
atmosphere, things like acid rain, we have not eliminated, but it’s much less of a
concern than it used to be.” “Yes, I remember being absolutely terrified
when I was growing up, and learning about it and I don’t think I’ve ever actually…witnessed
it.” “Yeah! No, but it does sound so awful!” “Oh, my God, acid falling out of the sky!” Yeah, it seems like we’re pumping less of
the bad stuff that creates acid rain into the atmosphere. So even though my elementary school textbooks
made me afraid to go outside in so much as a light shower, we’ve made real progress
in that department. It sometimes still happens, and natural habitats damaged
by acid rain will need more time to mend. But they are on the mend. But here’s an even weirder story from the
book… the story of Einstein’s lost refrigerator. The tale goes that Einstein — yeah, that
Einstein — was enjoying his morning cup of coffee when he read a tragic story in the
paper. Refrigerants at the time could be pretty toxic,
and an entire family had perished when their refrigerator sprung a leak. So Einstein called up fellow physicist Leo
Szilard and got to work. “They set out to build a better refrigerator. And they tried to make a whole new type of
refrigerator, one that didn’t use electricity, it didn’t have a motor, it was more based
on evaporating and cooling gases and mixing different gases in various clever ways to
basically take heat, move it around, you know, do different things.” Unfortunately, the Einstein fridge never took
off, because somebody came along and invented Freon right then. And fridges based on CFCs were a bit cheaper
and easier to make than Einstein and Szilard’s design. They just…also wrecked the ozone layer. “Imagine being the chemist who scooped Einstein.” “Yeah, it was actually a man named Thomas
Midgley. He was kind of well known because he invented
not only chlorofluorocarbons, he invented, uh, leaded gasoline as well.” “oooh, unfortunate …” “Unfortunately two of the worst ideas of the
20th century.” That’s a pretty terrible track record. We hope you’ll read along with us and everyone
at PBS. The Great American Read is a new series on
PBS about why we love to read, leading up to a vote on America’s favorite novel. Who decides America’s favorite novel? That would be you! Head to to vote
on your favorite book. And don’t let those other books win. Check the link in the description for more
details. Thanks for watching, and don’t forget to
subscribe, share, and turn on notifications. I could write my own book about how important
it is and how much it helps us out. See you next week!

11 thoughts on “Are We Breathing Caesar’s Last Breath”

  1. In high school, I remember some teacher relishing an anecdote about how every glass of water has a drop of Oliver Cromwell’s pee. Though, honestly, it’s not at all hard to figure out how Caesar gained such prevalence as a result of the patriarchy and white supremacy needed to keep imperial colonialism humming along.

    But, have you heard of the Capitalism and Schizophrenia duology, The Conquest of Bread, Das Kapital, or Mark Bray’s Antifa: The Anti-Fascist Handbook? Really nutritious food for thought, right there.

  2. we're all breathing each other's breath, minus the carbon that is extracted by the plants here. aside from the amount of oxygen that floats away into space at the atmosphere's top level. most of the air we breathe has been breathed by everyone who has come before us

  3. What is the percentage of atmosphere that leaks out into space every year? Why is that not part of this equation?

  4. I find it more interesting that when I drink something the water in it has been part of some dinosaur's pee. Can't remember where I read it but I did.

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