How many atoms do you have in Tutankhamen?

Everyone knows that if we talk about your identity - that which makes you a unique person - we are all nothing more than the sum of the atoms we are made up of. The food you eat, the water you drink, the air you breathe, and everything else that holds your body can be used as raw materials to create new molecules, cells, and parts of your body throughout your life. What are the chances that atoms in your body come from someone else in the past?

Let's say, let there be a probability in 0.0001% that there is an atom in your body that was once part of the pharaoh or queen. Can science tell something about how atoms move around the earth and where did the atoms of my body come from?

Well, science not only can tell you something about this, but also some interesting facts about what you are made up of.

First, let's get rid of any wrong preconceptions about what “you” really are. You think that you are made up of bones, muscles, skin, and other organs, but in terms of cells, these are only 4% of the cells in your body. The remaining 96% share blood cells and bacteria. Blood cells, most of which are represented by red cells, live only 120 days, after which they decay, are removed from the body, and are replaced by new cells that your bone marrow produces. Bacteria live everywhere: at every square centimeter of your skin at least a million bacteria, and tens of trillions of bacterial cells live in your digestive system.

Even at a more fundamental level, these cells are made up of molecules, which, in turn, are made up of atoms. If we were to break up the human body into its atomic components, we would find astronomical numbers of atoms — even more than astronomical — inside us: mostly oxygen, hydrogen, carbon, and nitrogen.

The atoms in each of your cells, even the calcium that makes up the bones, rarely stay in your body for long. They are also broken down, excreted into the bloodstream, filtered by the liver and kidneys, leave the body, and other atoms enter it and line up into new molecules and cells. If you compared your current body with your body in a week, you would find that 99.999% of your atoms were replaced. But at any given moment, your body roughly consists of:

• 1.7 x 10 ²⁷ oxygen atoms;
• 8.4 x 10 ²⁶ carbon atoms;
• 4.3 x 10 ²⁷ hydrogen atoms;
• 7.7 x 10 ²⁵ nitrogen atoms;
• and less than 1% is everything else, taken together, led by calcium, phosphorus, sulfur, sodium, potassium and chlorine.

Almost all of our oxygen and hydrogen comes from the water we drink and the air we breathe, and almost all carbon and nitrogen comes with the food we eat. Water and air circulate relatively quickly around the planet, so if you decided to find the last breath of Hitler, Caesar or Tyrannosaurus, you would find that everyone living on the planet has equal chances to breathe this air (provided, of course, that everyone breathes the same same number of atoms). But if you look at the carbon or nitrogen atoms that make up our bodies, they will be unevenly distributed. Since oxygen and hydrogen are the most common elements in the body, they can be considered as a comparison with two values: the entire atmosphere of the planet and all the water on the planet.

The mass of the entire atmosphere is about 5.15 x 10 ¹⁸ kg, which means that it contains about 4.1 x 10 ⁴⁰ oxygen atoms (and four times more nitrogen atoms); the sum of all the lakes, seas, rivers and ice caps in the world is poured into a mass of 1.35 x 10 ²¹ kg, which means 4.5 x 10 ⁴³ oxygen atoms and 9 x 10 ⁴³ hydrogen atoms. These numbers may seem large, but compared with the number of atoms in the human body is not so much.

If you cremate the human body by turning the water inside it into steam, allowing this water to return to the water cycle and evenly spread around the Earth, and then ask how many of these hydrogen and oxygen atoms can be found in the body of a random person today, you will be very surprised at the result.

One of every 2.1 x 10 ¹⁶ hydrogen atoms in your body was in the body of a random person; one of every 2.6 x 10 ¹⁶ oxygen atoms in your body was also in the body of a random person.

But we remember that in the body of an ordinary person there is somewhere 4.3 x 10 ²⁷ hydrogen atoms and 1.7 x 10 ²⁷ oxygen atoms. Which means that you have about 2 x 10 ¹¹ hydrogen atoms (or 200 billion hydrogen atoms) and 6.5 x 10 ¹⁰ oxygen atoms (or 65 billion oxygen atoms) from any previously existing human body.

It's a lot. Right now inside you are hundreds of billions of atoms left from King Tutankhamen, hundreds of billions of atoms of Hitler or Caesar, and if you look into the distant past, then the trillions of atoms that were part of the last tyrannosaurus when he died.

There are so many atoms that if we made such calculations for the air that you currently have in your lungs, we would find that approximately one atom in the lungs of each of us was in Caesar’s lungs (Lenin, Washington or Alexandre Dumas) during their last breath. Air and water molecules are evenly distributed fairly quickly and easily. But carbon, nitrogen, calcium and everything else are spreading much more slowly and unevenly, so you may have millions or billions of these atoms from historical figures for every taste, or not at all. (Tutankhamen was mummified, which means his water and air returned to Earth, but carbon and nitrogen remained).

Think about it the next time you take a deep breath or drink water. At this moment you will breathe the same air and drink the same water with every person on Earth, and even with the very first creatures of the earth. At the level of atoms, we are connected more abruptly than the rule of five, seven or one hundred thirty-five handshakes can suggest.

The article is based on materials https://hi-news.ru/research-development/skolko-v-tebe-atomov-tutanxamona.html.