13.8 Billion Years Later

An interview with Dan Levitt and the immense journey from the Big Bang to the dinner table in his new book What’s Gotten Into You.

Imagine the world’s largest skyscraper. Actually imagine a billion of them, each one larger than the largest building ever built. Only then will you come close to imagining a number of rooms more or less equal to the total number of cells in your body—30 trillion or so. Now imagine everybody on the street. You each have 100 times more cells in your body than there are total stars in the Milky Way galaxy, and they all come from the same place.

Some 13.8 billion years ago, there was an explosion, a random but significant rapidly expanding primordial soup of quarks, gluons, electrons, heat, and plasmas: All the matter in the entire universe, created in an instant. And here we are. All life, including yours, is made up of those same basic particles that came from the Big Bang. How did that randomness create us? How did it give rise to the complex mechanisms in our body?

That’s the subject of journalist and documentary filmmaker Dan Levitt’s first book, What’s Gotten Into You: The Story of Your Body’s Atoms, from the Big Bang Through Last Night’s Dinner (HarperCollins). The book is an immense journey and a deep dive into an endless and endlessly fascinating subject. caught up with Dan this month to ask him about it. Did you really get the idea for this book from when your teenage daughter wanted to give up eating meat?

Dan Levitt: It really did start with my daughter, who thought about becoming a vegetarian as a teenager. And I started wondering what our bodies were made of and realized that I didn’t know what my body was made of or what her body was made of—much less where any of that stuff came from. And so I did some head scratching and a lot of Googling, and ultimately I realized that atoms are forever and that every single particle in our body came from the Big Bang, 13.8 billion years ago. And when you think about that journey of those particles from the Big Bang, the creation of the elements, the origin of the solar system, how our planet was formed, the origin of life, how our planet was completely transformed by photosynthesis, and then how those how those molecules found their way to us, it’s really an epic story. 

And what made it for me more epic was also looking at how we discovered these things. I mean, on the face of it, it seems impossible that we could look so far back in time and know so much about the history of what’s inside our bodies. With the Big Bang, you had gluons and quarks and electrons, and they formed atoms, and we are here 13.8 billion years later, little collections of those gluons, muons and electrons, and they’re able to look back over time and retrace the history. For me, that’s just—when you stop and think about it—it’s really amazing. 

I feel like the general public interest in all the small things in life is focused on the extremely small end—the subatomic, quantum physics realm more than the molecular, biochemical realm. Why is subatomic physics so popular? 

Part of it, I think, is because there’s so much mystery, because quantum mechanics and the behaviors of the atomic particles are so non-intuitive and really make us think that there are so many aspects of reality that we don’t really understand—to the extent that people are pursuing string theory, even though the mathematics is so complex that there are only a few people in the world who actually can comprehend it. 

Joni Mitchell, you know, said we are stardust, right? And that idea that we are made of star stuff is literally true because with the exception of hydrogen, every element in our bodies was made in giant stars or in the explosions of giant stars and supernovas. And what makes it even more interesting, of course, is now that we’ve discovered that there are organic molecules floating throughout the universe—that the universe is permeated with clouds of organic molecules—which suggests so many things that I think are fascinating for us to think about. One of them is [that] to many people, it suggests the inevitability that life is not just here but in other places. 

When we’re talking about quantum physics, let’s say, in the general public sphere, you will find both traditional researchers presenting their theories—as well as more than a few crackpots with crazy ideas that seem paper thin at times. How can you spot the few Galileos of our day who sound nuts but the things they are saying are going to turn out to be completely correct—versus all the others whose ideas really just are crazy?

One of the things that happened in my book is I traced the development of so many breakthroughs, and I was looking at how they were received by scientists at the time. And it was, much more often than not, both skepticism and scorn—not just by a few people whose turf was being encroached on but by entire communities of scientists.

In my book, I came up with six cognitive biases that keep people from recognizing in the short term (not in the long term) great breakthroughs. [One of these is the statement], “It’s just too weird to be true,” which was Einstein’s reaction to the Big Bang and the expanding universe. 

“93% of the dry mass of our bodies is actually a product of photosynthesis.”

Or “If our current tools don’t detect it, it doesn’t exist.” In the 1920s, people couldn’t see inside the cell, and they were sure that the only things that created life in our cell, other than a nucleus, chromosomes, and mitochondria, were enzymes. The whole idea of any kind of other structures and nanomachines or molecular motors of any kind—they just didn’t believe it was possible until, you know, they were proven wrong. And so it’s a fine line. 

What was interesting was that in the long run, people did come around, and they came around because scientists as communities are open to evidence. But, you know, when you’re a scientist out there and you really believe in something, it’s hard. It’s hard to know when to stop and when not to. And I think for me, what came through in looking at all these case studies was, number one, we just need humility. Instead of saying this is true, perhaps we should be saying, “This is true as far as we know, with the evidence that we currently have.”

You have said we are constantly being deluged with new discoveries. Does all the attention paid to science in the media make science more accessible?

New scientific papers, as someone once said, [are] really like spitballing. You put an idea out there, right? And you hope that other people will be attracted to it, and they will appreciate the evidence you’ve found, and they’ll build on it and find more evidence. But you know, it’s not uncommon that there are so many issues that science investigates that we don’t have answers to—we have competing hypotheses—and sometimes one is in favor and sometimes another is in favor. And in the end, by being open to new evidence, I think we do approach and get much closer to some sort of reality. But nonetheless, if you’re looking at the internet, you will see all the time: Scientists have just discovered the secret to how life first formed, and it’s this chemical that’s on Mars. And then next week, scientists have just discovered the secret to how life just formed, and it’s this reaction at a hydrothermal vent. And the way the science is packaged, the clickbait, which says, “we may just have found the answer to…” is misleading, because it over inflates the degree to which that evidence actually confirms the theory as opposed to supports it or suggests a new one. And I suspect that’s a bit confusing as well for a certain population to constantly see people say one thing and then another thing. 

Who bears the blame? 

Well, I do think that the clickbait headlines that overinflate what scientists discover, I don’t think that helps. But in the end, I think there’s something much larger. I think there are just a lot of people who decide that they’re going to take their understanding of science, not from scientists, but from other people. And I think there’s something about the way the brain works and how we decide what we think is true and mesh it with what we already believe to be true that leads a lot of people to be open to ideas that don’t fit with what most scientists believe.

The story you told at the very beginning about your daughter becoming a vegetarian and how that sent you on this journey… Did she become a vegetarian? 

So she did become a vegetarian, and I did write the book. Each chapter in the book poses a different mystery. How did we learn about the Big Bang? How did we learn what the smallest particle in our body is? How did we learn how a planet habitable for life formed? One of the chapters is about how did we learn what we need to eat to survive. So it traced the history of how we learned about carbohydrates and proteins and vitamins and minerals and so on. I talked to a number of nutritionists, and I learned pretty quickly that it’s very easy to have a very healthy vegetarian lifestyle—it’s not a problem. 

Having said that, then my daughter did a lot of traveling, and she discovered that when she went to other cultures, sometimes when people invite you to eat, it’s hard to say “no” in somebody’s house if they don’t have a vegetarian option. So now she and our house—we’re largely vegetarian, but we eat meat occasionally. 

Somewhere Michael Pollan is smiling.

“If you took the 30 trillion cells in your body and stacked them up, they would go to the moon and back like 27 times.”

One of the amazing things that I learned was that almost everything in our body was, at one point, created by plants. The minerals were collected, but most of the vitamins were made by plants. I could go on forever about photosynthesis, but one of the things that I love is that about 93 percent of the dry mass of our bodies is actually a product of photosynthesis. That is, 83 percent of the mass of our bodies is just carbon dioxide that was just floating through the air. And another 10 percent is hydrogen from water. That’s 93 percent of us, right? Thank you, plants, and thank you, other photosynthesizers because without that, we wouldn’t be here. 

What are some of your favorite quantified facts about the human body? 

First of all, I think there’s a sense in which we’re something like three by ten-to the 27 electrons: That’s what you are made of. Scores more gluons, scores more quarks. And there’s a sense in which that’s all you are. You’re also 30 trillion cells. And each of those cells is made up of about 100 million atoms—every cell in your body. And by the way, if you took those 30 trillion cells and stacked them up, they would go to the moon and back like 27 times. 

And our cells, as you know, are made of mitochondria, which create ATP, create energy for us. There’s an average of 2,000 of them, in our cells. If you took all the mitochondria in our body and laid them out, they would cover two basketball [courts]. And they’re consuming something like two thirds of a pint of oxygen a minute. That’s how we create our energy. We have mitochondria, which are more efficient than the mechanisms the bacteria have to generate the energy which we need in order to run around. Without that oxygen in the atmosphere, you know, we wouldn’t be able to generate the energy that we need to be active creatures. 

And then I have other fun statistics. We’re composed of about 24 essential elements and about 60 others—because whatever gets into the dirt gets into your body. But, you know, your body contains about 25 pounds of charcoal, enough salt to fill a saltshaker, enough chlorine to chlorinate several backyard swimming pools, enough iron to make a three-inch nail. And by the way, that iron—most of it is in the hemoglobin in your bloodstream, because it’s carrying all that oxygen to your cells in order for your mitochondria to generate the energy that they need in order for us to create about the equivalent of a 100-watt light bulb of energy [which is] what we generate in resting state. 

A color enhanced scanning electron micrograph of mitochondria (green) in an ovarian cell. P.M. Motta, S. Makabe, T. Naguro / Science Source
How did this book change the way you think about the human body? 

The fact that we’re 30 trillion cells, each of those cells is packed with all kinds of pumps and ratchets and literally nanomachines, things that make other things move, like ATP synthase, which revolves at up to 300 revolutions per second, generating ATP for energy for us and can actually revolve backwards. And it’s got one part that creates an ATP and another part that kicks it off the mechanism. And it really gave me a deep appreciation of how amazing our body is and how deeply complex it is in a way I don’t think we can actually truly comprehend. 

How much is down there within our bodies and within our cells? How much goes on within a single cell in our body? It’s really hard for us to wrap our heads around. There’s a way in which it’s really given me a much deeper feeling of respect for all of us because we are unbelievable creatures. Of course the brain, we know, is the most complex structure in the universe. But our cells are also really unbelievable. And, you know, the other thing that I did come away with was a strong sense of how much of those mechanisms we inherited from single-celled organisms, like bacteria—that we have so much kinship with those other organisms as well. And so that’s given me a really strong sense of how deeply interconnected life is and how strongly we are connected to not just the web of life, but to all kinds of organisms everywhere. 

What books are you reading right now? 

I’m reading a number of books simultaneously. One of them is a book by Simon Winchester [Knowing What We Know: The Transmission of Knowledge From Ancient Wisdom to Modern Magic]. It’s his latest one that just came out and it’s basically about the history of the development of knowledge in the world.

And then for fun, I’m reading a book called Republic of Pirates, which is not about science, it’s about history. It’s a fascinating history of the golden age of pirates in the Caribbean. And what’s so interesting to me was how deeply embedded that was in the colonial trade with England and the United States. And that so much of the history of the Caribbean is so deeply marked by the colonial plantations and the pirates as well. And plus, I’m from Philadelphia and now I live in Boston, and learning that Blackbeard, who I’d not really thought about, was a real person who was cruising off of Philadelphia and off of Boston and was actually not just some guy but was a person of real significance in history. That’s really been fun. 

Editor’s note: This story was updated on 9/1/23 to reflect that the 93 percent of our bodies being the product of photosynthesis refers to the dry mass.

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