You have billions of William Shakespeare’s  atoms inside of you right now!

If you make a habit of watching  science videos on YouTube,   maybe you’ve heard that kind of claim before. And you can see why it’s appealing.

Who wouldn’t like the idea of having a little   bit of the Bard … or any other Great  Person From History … inside of them? But is this true? And also, how do we know?

Well, strap in, because I’m  about to break it down for you. And the numbers are gonna get really, really big. [♪ INTRO] To figure out how many bits  of Shakespeare are in you,   first we need to know how  many there were to go around. Like everything else in the universe,  the Bard was made entirely of atoms.

There were a variety of different elements,   but mainly carbon, hydrogen, oxygen,  nitrogen, phosphorus and calcium. Together, those six elements  make up about 99% of our bodies. So for our purposes moving forward,  we can ignore everything else.

Now, when you know the elemental  composition of a thing, and you   know the mass of a thing, you can work  out the number of atoms in that thing. An average body weighs approximately 80 kilograms,   and is made up of the six elements I  mentioned before in decreasing quantities. And from those elements’ masses and  proportions, we can calculate that   there are roughly 7 octillion, or 7 x 10^27 atoms in the average human body.

But it’s not as simple as that, because  human bodies are surprisingly impermanent. Around 98% of all of the atoms  inside our bodies are swapped   out regularly as the living tissues are renewed. The fastest molecule to be recycled is water,   containing a ton of our  bodies’ hydrogen and oxygen.

Around 60% of our bodies are made up of water,   and scientists estimate that around  half of this is replaced every 8 days. Carbon, sodium, and potassium are  major constituents of soft tissues,   and are also recycled quickly. But calcium and phosphorus, which are the stuff of  bones and teeth, tend to stick around for longer.

Regardless, many of the atoms that  leave our body in our breath, sweat,   urine and feces were a part of us once. Let’s look at breathing first. The average volume of a  breath is about half a liter,   but since about 75% of the air we inhale  is inert nitrogen that the body can’t use,   less than 25% of each breath is  actually exchanged with the body.

But even in just that quarter of a  breath, we shed about 10 sextillion atoms. Multiply that by an average of 15 breaths per  minute, and you get 8 million breaths a year,   amounting to 80 octillion atoms  shed through breath alone. We can do the same with solid and liquid waste.

On average, we produce 128 grams of  feces and 1.4 litres of urine per day,   which together contribute to about 100  octillion atoms released that way every year. So, if we’re trying to calculate how many  Shakespearean atoms there were to go around,   we need to consider all of these sources. The Bard lived in England during the 16th century,   and he resided there for 52  years before his death in 1616.

He was buried at Holy Trinity  Church in Stratford upon Avon,   and his body would have decomposed for more than  a decade until all that was left was a skeleton. Actually, a little less than a full skeleton. In 2016, radar scans of his tomb appeared to  show that the playwright’s skull was missing,   thought to be looted by graverobbers.

So we might have to rule  that out of our calculations. But as we’ll see, it won’t  make that much of a difference. Shakespeare had 7 x 10^27  atoms in him when he died,   most of which would have gradually  made their way into the environment.

But much more significant were the atoms  that he released during his lifetime. Over his 52 years, he breathed out  about 4 nonillion, or 4 x 10^30 atoms,   and peed and pooped another 5 nonillion. Together, that makes 9 nonillion atoms.

Which is a thousand times more than he was  still hoarding in his body when he died. So these 9 nonillion atoms have been  out in the wild for the last 400 years. And to find out what happened to them, we need to  shift our focus from the small to the very large.

On the whole, the Earth is kinda clingy  … at least when it comes to its atoms. Since everything arrived here about four and half  billion years ago, almost everything has stayed,   compelled by the force of bonding in solids,  cohesion in liquids, and gravity acting on gases. There is a slow leak at the top of the  atmosphere, where the lightest elements,   hydrogen and helium, are escaping at  a rate of about 1 kilogram per second.

But while that might sound like  a lot if we were talking about a   leaky tire, on the scale of the  atmosphere, it’s insignificant. So just about all of the elements that  have ever been on Earth stayed here,   and are cycled through the ground,  air, water, and living things. And the so-called biogeochemical cycle  of each element looks a bit different.

Carbon, for example, is a major  component of all organisms. We’re about 18% carbon, and a big portion of the  Earth’s carbon cycle passes through living things. The element is absorbed from the atmosphere  by plants and algae during photosynthesis.

Those plants are eaten by animals,  the carbon is passed along, and the   element is ultimately released again  during respiration and decomposition. Another big portion of the world’s carbon is in  the atmosphere, in the form of carbon dioxide. Quite a bit of that CO2 dissolves into  the oceans to make a weak carbonic acid.

And with or without the help of living things,  calcium carbonate can precipitate out and lock   away some of the carbon in sedimentary  rocks for hundreds of millions of years. Nitrogen is another important element  on the Earth and in our bodies. It makes up 78% of the air,  and about 3% of living things.

But nitrogen doesn’t cycle  quite as easily as carbon does. To change from an inert gas in the atmosphere  to the nitrates that living things use,   it needs to be ‘fixed’ in chemical reactions  that require bacteria, or lightning, to happen. Once bound inside tissues, it  follows much the same fate as carbon,   being passed along when organisms are eaten,  and released again when those organisms die.

And then there’s water, which is the planet’s  biggest reserve of hydrogen and oxygen. 71% of the surface of the earth is covered in  the stuff, and human bodies are 60% water too. It evaporates from the oceans, condenses into  clouds, moves around through the atmosphere,   then rains down to the ground where  it flows over or under the surface. It’s taken up by living things, released  when they don’t need it any more, and   ultimately ends up back in the ocean.

There are so many different places water can go,   and each place hangs onto it  for a different amount of time. A water molecule might spend 3,000 years  in the oceans, 9 days in the atmosphere,   and hundreds to thousands of years as groundwater. But there’s no knowing what  route each molecule might take.

However, the fact that this,  and all of the other cycles,   have major components in the atmosphere, does  offer the opportunity for atoms to travel. Which turns out to be crucial. But before I tell you why, a quick ad.

We hear that you want merch—and we hear  that you want to support Complexly. Did you know when you buy merch, you support us? Its true!

So here’s the DEAL - the SciShow store  is having a huge summer sale right now. Because even the most generous people LOVE A DEAL! You can support your favorite  free science content on the web,   and get an extremely cool  pin that everyone will love.

Like our Wandering Womb pin, inspired  by the follies of doctors of old. If pins aren’t your thing,  we’ve still got you covered. It’s hot out there, so you should probably  stay hydrated, and what better way is   there to enjoy your favorite beverage  than in the SciShow Space Donut Mug?

You can sip all day while marveling at the fact  that our universe may be shaped like a pastry. Or if you prefer your drinks in a can,  keep it ice cold in our SciShow can koozie! We’ve even got a few favorite items  from our SciShow Rocks subscription   that you can pick out, no membership required.

Every rock and fossil has a  story, so you can’t go wrong. Selected merch is up to 45%  off, so get it while it’s hot! Plus, you’ll get a free SciShow pin at  check out if your order is over $50.

Be part of the nerdy things revolution. Head to Complexly.store/sale now. The sale ends August 15th, so don’t wait!

Time, and magnets, are running out! The air is a freely mixing fluid, and  scientists estimate that it takes about   a year for molecules in the atmosphere  to move from one hemisphere to the next. While there’s a chance that some of Shakespeare’s  atoms have been locked away in rocks, or deep in   the ocean, the rapid biological cycles that  use them keep many of them in active service.

And the air keeps them moving. It’s a reasonable assumption that, in the 400  plus years since his death, the atoms that once   called Shakespeare home are now distributed  more or less uniformly across the planet. Although it’s not possible to trace the  fate of any single one of those atoms,   we can make an educated guess as to where  they’ve ended up, using probability.

If Shakespeare is now well  mixed in the environment,   and we are ultimately built from atoms in  the environment, then we can be expected   to assimilate bits of the Bard in the  same proportion as they exist there. The number of Shakespeare’s atoms in you will  be the number of his atoms that exist, divided   by the total number of atoms in the environment,  multiplied by the number of atoms in your body. We already know the number of  Shakespearean atoms in play:   during his life and after death,  he shed about 9 nonillion atoms.

Calculating the total number of atoms in  the environment is a bit more involved. The environment, for these purposes,   comprises the parts of the Earth through  which the biogeochemical cycles pass. It includes the low, circulating part of the  atmosphere called the troposphere, the ocean,   a portion of the land surface, and living things.

And just as we used mass and elemental  composition to work out the number of   atoms in a human body, we can do the same  for each of these parts of the planet. I’ll save you the math, but the  troposphere has 3 x 10^44 atoms… The oceans have 1.2 x 10^47 atoms… A thickness of land about 1 meter  deep is about 2 x10^43 atoms… And the biosphere has 3 x 10^41 atoms. If you’re already zoning out from all  the powers of ten, I do not blame you.

But the takeaway here is that the oceans  are much bigger than any of the others. They contain 400 times more atoms than the air,  and 400,000 times more than all living things. So statistically speaking, the total number of  atoms in the environment is around 1.2 x 10^47.

That’s 12 with 46 zeroes after it,  equal to 120 quattuordecillion. I did not know that number even had a name! So we have the number of Shakespeare’s   atoms floating around and the total  number of atoms in the environment.

Dividing the first number by the second gives  us the probability of randomly plucking one of   Bill’s atoms from the environment at 7.5  x 10^17, or nearly one in a quintillion. I don’t know about you, but one in a  quintillion doesn’t sound like great odds. Not sure I’d buy that lottery ticket.

But we’re not just buying one lottery ticket. To build a human body, we need to pick  up a lot of atoms from the environment. Like, as we calculated  before, 7 octillion of them.

And when you’re buying that many lottery tickets,   even with vanishingly small odds, you’re  going to hit the jackpot eventually. Multiply the odds by the number of atoms you  need and, voila, you’ve got your Shakespearean   atomic winnings - which come out to about  525 billion atoms in every single one of us,   just from randomly plucking them  out of our air, water, and food. It sounds like a lot, even after dealing  with all of those zeros, but consider this:   525 billion atoms is less than 100 trillionth  of a percent of all of the atoms in your body.

Now, purists might not consider the atoms that he   breathed or peed during his  life to be his ‘true’ atoms. So if you only want to count the bits  of him that were left when he died,   then we have to adjust the number down a bit. Even so, it still comes out at about 400  million dead Shakespeare atoms in all of   us … maybe a bit less depending  on the whereabouts of his skull.

Now, there are a ton of assumptions  built into all of these calculations. For one thing, we’re assuming that after he died,   all of Shakespeare’s atoms were uniformly  dispersed through the environment. But it’s hard to know how true that is.

The ocean is by far the biggest reservoir  of atoms on the Earth’s surface,   and water tends to stay there for much  longer than Shakespeare has been dead. So the H2O that ended up there might not make  it back out to become a part of our bodies. And since carbon and nitrogen are such  essential parts of all living things,   they’re more likely to keep  churning in biogeochemical cycles.

So we’re more likely to inherit those parts  of the Bard than any of his other atoms. Taking time and place into consideration  also introduces some interesting patterns. It goes without saying that,  the more recently someone lived,   the less time their atoms have had  to get mixed into the environment.

So you’re more likely to have Shakespeare  in you than Marie Curie, for example. And if 400 years isn’t enough to  distribute atoms around the globe,   then you’re more likely to have Shakespeare  in you if you live in England, than if you   live in Australia, because you’re  closer to where he lived and died. However, English pigs and sheep probably  have a bigger chunk of the Bard in them,   because they’re directly grazing the ground where   he was buried and where his solid  and liquid waste was deposited.

The amazing thing is, pigs, sheep, Brits,   aussies, and all of us don’t just  have bits of Shakespeare in us. We have bits of everything, and everyone. The conservation of atoms on Earth means that  everything is recycled over and over again.

The bits of us that were once  part of Shakespeare may have   also been part of Cleopatra, a T  Rex, and the earliest lifeforms. And because we shed most of our  atoms while we’re still alive,   there’s a good chance that you  have some of my atoms, too. Running the numbers, and allowing a  decade or so for atoms to get around,   about 400 billion of my atoms  have made their way to you.

Although I won’t take offense if you  think it’s cooler to have Shakespeare’s. [♪ OUTRO]