As a little boy I used to love reading books about dinosaurs and gems and the different kinds of lightning. My favorite was a book entitled Tell Me Why. Written by Arkady Leokum, it gave simple answers to the questions that kids ask: Why is it hot in the summer? Why is the sky blue? It was even honest about the deeper questions that scientists were still trying to solve: How did the universe begin? Why do we have to sleep?
More than half a century later, I’m still curious about those deep questions, as I suspect you may be too. So when the editors of Quanta Magazine invited me to host a new podcast series about some of the biggest unanswered questions in science and math today, I was delighted to say yes. We are calling it The Joy of Why. It’s a natural evolution of our previous podcast together, The Joy of x, which also involved conversations with leading scientists and mathematicians. This time around, though, we focus on their ideas and discoveries instead of their personal journeys.
It has been such a thrill talking to these experts about the eternal mysteries and the latest thinking about them. Take, for example, what we learn in our episode about the origin of life. The Nobel Prize-winning biochemist Jack Szostak tells us that a key molecule implicated in the origin of life is now thought to be … cyanide. If that’s correct, how ironic that a molecule so deadly today may have been so vital at the beginning!
Later in that episode, we hear from Betül Kaçar, a molecular paleobiologist who studies ancient molecules using inferences drawn from her computer-aided evolutionary analysis of the variants seen in modern bacteria. (It’s akin to what linguists do when they try to infer the words of an ancient language, say Indo-European, from the word variants used in different languages today.) The ability to make such inferences is cool enough on its own, but to my astonishment, Betül goes on to explain how she was able to synthesize those hypothetical ancient molecules in her lab, resurrecting genes and enzymes that bacteria seem to have stopped using billions of years ago. When she tested those ancient genes by inserting them into the genomes of modern bacteria, as if she were putting spark plugs from a Model T into a current-model Ferrari, the results were both eye-opening and comical.
If I had to single out a recurrent theme in the episodes of The Joy of Why, it might be the power of modern technology to illuminate timeless questions. Why do women tend to live longer than men? With modern genetic engineering, the neuroscientist Dena Dubal is teasing out whether it’s hormones like estrogen that make a difference or whether it’s something about the presence of a second X chromosome that matters. How can we look back in time to the birth of the very first stars and galaxies? The astrophysicist Marcia Rieke explains how the James Webb Space Telescope aims to capture that unimaginably faint early starlight with super-sensitive infrared detection technology — a new tool that’s similar in spirit (but light-years beyond!) the night vision goggles used by soldiers, hunters and police officers.
The revelatory power of new tools came home to me most personally in my conversation with Dragana Rogulja, a sleep scientist who has been using the latest gene editing and imaging technologies to probe the mystery of why we need to sleep. For at least a century, it has been known that prolonged sleep deprivation is inevitably fatal. But no one has ever been able to figure out why. What exactly is the cause of death? Or, to flip the question around, what essential purpose does sleep serve? Back when I was doing my doctoral research on the mathematics of sleep, I once sat spellbound in the audience at a major sleep conference while a distinguished researcher suspensefully described his latest attempt to crack the problem. Alas, his experiments proved inconclusive and only deepened the mystery.
So when Dragana told me about her new experiments and their shockingly clear and unexpected results, I felt like I was having a Rip Van Winkle moment. It was almost too poetic: I had awakened, 40 years later, to finally learn what sleep is for.
It’s not just the experimentalists who are benefiting from the power of new technology. In our episode with the theoretical physicist Sean Carroll, he reveals how conceptual and calculational techniques developed recently for the study of quantum gravity and entanglement are leading us to a new understanding of space and time. If these new ideas turn out to be right, they imply that something strange is happening in the bedrock of reality: Space and time are somehow emerging from something even more fundamental, something ineffable and quantum mechanical at its heart.
I don’t want to oversell the importance of new technology, however. One of my guests reminded me that in the hands of the right person, even an old tool may be powerful enough to crack a long-standing puzzle. The mathematician Lisa Piccirillo was a graduate student when she heard about an unsolved problem involving a peculiar tangle called the Conway knot. She couldn’t see why the problem was so difficult. In a matter of days, she solved it with the help of a decades-old mathematical tool (known as the “trace” of a knot) that she borrowed from a neighboring area of topology. When you listen to her joyful laughter as she tells the story, you will be reminded that the greatest tool of all has stayed the same throughout the history of science: the curiosity and drive of a creative young person.
Please join me and my guests on The Joy of Why. New episodes will be released every other Thursday, starting March 24, and will be available here or wherever you get your podcasts.