Read the full transcript of Greek-born accelerator physicist Dr. Lia Merminga’s talk titled “How Tiny Particles May Explain Why We Exist”, at TEDxChicago, June 23, 2025.
Listen to the audio version here:
Dr. Lia Merminga: I have been a scientist most of my life. In fact, I think I was born to be a scientist. I grew up in Athens, Greece and questioned everything. I wondered what it would happen if I kept walking to the edge of Earth. Later, of course, I learned there is no edge of Earth. In school, I liked science and math. Math had a certainty that I felt drawn to.
To me, it was a marvelous thing that we could use math to describe physical phenomena, to describe the complexity of the world around us with simple and elegant mathematical equations. I had a chemistry set in my room and the kids in my neighborhood were wondering when I’d blow up my house or even the whole neighborhood. And I read the biography of Madame Curie when I was 13. And I had an amazing female physics teacher in high school who epitomized who I wanted to be. And my mother and grandmother would tell me stories about my mysterious physicist uncle who had a brilliant career in the United States until his untimely death at 36.
And then, at the University of Michigan in Ann Arbor, where I went to graduate school, deep in the bowels of the library, I would flip pages learning about particle physics, which is the study of the fundamental constituents of the universe around us, and about particle accelerators, powerful high-tech machines that propel the tiniest pieces of matter to close to the speed of light. And I wondered, why do we exist? I read about brilliant physicists and about Nobel laureates, all these people who have helped define our field. And then one night, I stumbled upon someone familiar.
This is a picture of my mysterious physicist uncle, George Tosmanis, when he was a graduate student at Columbia University in the late 1950s. I never knew him as a person, but I got to know him as a scientist from his publications and from my professors who had worked with him. And learning about my uncle and his journey in physics, I felt the intergenerational connection to all the scientists who had been there before me, to Madame Curie, to my uncle, to my teacher. Now I understood it was my turn to be a pioneer, a torchbearer in physics.
Today, I am the director of Fermilab, America’s national laboratory for particle physics and accelerator science. Today, I get to ask in my job the same questions I asked as a kid in Greece and as a student, except now I also get to answer some of them. We at Fermilab are building the best experiment in the world to try to answer the question, why do we exist?
But we cannot do it alone. The question of why we exist, like so many other questions in particle physics, are profound and difficult and challenging. They take people from all kinds of expertise and backgrounds and talents and experiences to come together to find the answer. It takes more than a village, it takes more than one lab, it even takes more than one country. It takes the entire planet to do particle physics.
Let me give you some examples of modern-day international scientific endeavors that you may be familiar with. The first is CERN, the European Organization for Nuclear Research. CERN is the largest particle physics laboratory in the world and one of the most respected research institutions. And then the International Space Station, it is the largest space station ever built. And the James Webb Space Telescope, the largest and most powerful telescope ever launched in space. And right here in the Chicago area, we are building DUNE, which adds to this impressive list of international science missions. DUNE stands for the Deep Underground Neutrino Experiment. And it is hosted by Fermilab. And like CERN and the ISS and the James Webb Telescope, from its inception, DUNE has been a truly international effort. In fact, DUNE is the first international mega-science project hosted by the United States Department of Energy on U.S. soil, and we are hosting it.
So all four of these examples, these awe-inspiring international science missions, were created with people from around the globe. And they provide us with science that pushes the boundaries of what we thought to be possible. But let’s go back to DUNE. So the DUNE collaboration is made up of more than 1,400 people from over 200 institutions in over 35 countries plus CERN. And we are all coming together, united, in the common pursuit of knowledge. And we are all pushing the boundaries of science, engineering, and technology in the pursuit of the big question, why do we exist?
Well, it turns out the answer to this question may be deeply connected with the breaking of a fundamental law in physics by elusive particles called neutrinos. But let’s take it from the beginning. When the universe was first formed in the Big Bang more than 13 billion years ago, scientists believed that matter and antimatter were created in equal amounts. But if that were the case, then matter and antimatter would annihilate each other, leaving nothing but pure energy. But clearly this did not happen because you and I are here today and we’re made of matter. So something must have happened that avoided the total cancellation of matter and antimatter at the very early stages of the universe. We don’t know what it is, but whatever it is, we know it is the reason we’re here today. And we believe that neutrinos play a big role in the answer to this mystery.
Let’s talk a little bit about neutrinos. What do we know about neutrinos? First of all, neutrinos are elementary particles in our universe.