Stephon Alexander
The Jazz of Physics
TEDxSanDiego 2015

I play the sax, but I wasn’t playing the sax like that guy, the guy with the dreads, when I was his age. They were amazing. Let’s give it up to them.

Music has this mysterious power to affect us so deeply. Never in my wildest dream, when I started off in my career to become a physicist, did I ever think that there would be some deep connection between the functioning of our universe and music.

I want to take you a little bit on that journey today. The journey begins at DeWitt Clinton High School, which is where I went to high school, in the Bronx, New York, in the 80s.

DeWitt Clinton was the second most populated high school in New York City, with about a 60% dropout rate. However, we had teachers there who deeply cared about our wellbeing and our education.

During 10th grade, our first day of our physics class, all of the students were anticipating Mr. Kaplan to walk into the room and walk to the front of the blackboard and write down some daunting equations.
He did the exact opposite. That’s a picture of Mr. Kaplan when he was a younger chap. It was the only picture I was able to get. Kaplan, at the time, had a wild Einsteinian haircut, and he walked into the room with a frail limp, and actually went and sat in the middle of the room on someone’s desk.

He reached into one of his pockets to get some mysterious object, which actually made the thugs in the room a little bit concerned. It was just a simple tennis ball.

He took the tennis ball, looked around, threw it in the air and caught it. I’m glad I caught it. Then he asked the class, “When the ball was at the top of its flight, it had zero velocity. Right before it hit my hand, what was the velocity of the ball?”

We were about 14 and 15 years old at the time. I was fascinated by this, because I didn’t have to solve any equations. In my mind’s eye, I had imagined of the ball going up and down, up and down, in slow motion.

I instinctively raised my hand. I said, “Right before it hits your hand, it’s exactly the same velocity as when it left your hand.” Mr. Kaplan got up and said, “This is brilliant. Intuition is the life blood of a great physicist.”

I thought, “Really?” It was the first time in my life that a teacher actually exuded that I was smart.
After class, Mr. Kaplan called me into his office. I went to his office. He had this huge office, because he was the chairperson of both the music department and all the science departments.

They had all these books. This was one of the books. It’s about a 2000-page book on gravitation. He said to me, “You know, Stephon. I think you have what it takes to be a good physicist.”

I was thinking “What? I haven’t even had one class with this guy yet. What’s he talking about?” He said, “Do you know about Einstein’s theory of gravity? Space is not what you think it is. Space is warped. The universe is expanding.”

He said, “What kind of music do you like to listen to?” In his office he had, on one side, a picture of Albert Einstein and then on the other side of the office, he had a picture of someone I didn’t know.
Although I did play around with a saxophone when I was younger, I actually didn’t know who this gentleman was. It was John Coltrane, of course.

I wondered, “Why does this man have these two people in this office?” I know about Einstein. To make a long story short, he told me, “What kind of music do you like?” I said, “I like rap music.” He said, “What about jazz?” I said, “You know, I like Kenny G.”

He said, “Come back to my office next time.” I came back and he handed me a CD. He said, “This is real jazz.” It was John Coltrane’s album, Giant Steps.

The years progressed along. I discovered something very interesting about Mr. Kaplan. Mr. Kaplan was trained as a master composer. He was on his way to a very successful career as a composer, but he got drafted in the Korean War.

During the Korean War, he got involved in radar. While working on radar, he caught the physics bug, because radar is about physics. When he came back, he pursued a career in physics and then became the head of the physics and music department, pursuing both careers. He was also a jazz musician.
Mr. Kaplan could have taught at any of the elite schools, including Bronx High School of Science, which was next door to Clinton, but he chose to be right there in that room with me.

I caught the Kaplan bug. Mr. Kaplan said, “You have to take calculus. You have to go to college, go to grad school, get a Ph.D., and then you can understand this book.” I did that. It took 20 years to do that.

Fast forward 20 years, I am in London at the Imperial College, the theoretical physics group, and I start to feel like that 10th grader again. I start to feel completely inadequate. There were all these other physicists there who I felt had a lot more than I did. I was getting nowhere in my research.

In that moment of despair, I remembered Mr. Kaplan. I remembered Mr. Kaplan being true to himself, paving his own path, improvising his life. I decided, “If I’m going to go out, I’m going out with my horn.”

What I did was I started to hang out in the jazz clubs in Camden Town, London. During the summertime, I used to go to Smalls. I would bring my physics papers, my research and my calculations, to the jazz clubs.

Now I’m in these jazz clubs, in the middle of the night, talking to the jazz musicians about my physics ideas. I used to tell them about the expanding universe. They would give me weird looks.

There was a time when a pianist was playing. I looked at another horn player and said, “Man, his playing is quite geometrical.” The guy said, “I don’t know what geometrical is. The stuff just sounds good.”

That was the story. One thing happened that was quite interesting. During that moment, I realized that I was starting to have intuitive leaps in the jazz clubs, sometimes irrational thoughts that would lead me to solve problems.

Many of us think that being a good scientist is about being rational and locking yourself in room, calculating at a desk, or in a lab with a lab coat. No. Sometimes to get to the answer requires you to be irrational.

That’s what was happening there. That led me to solve a couple of problems and got me tenure at Dartmouth College.

It turns out that I learned something very interesting. I wasn’t the first to do that. It actually turned out that at the very birth of astronomy, going back to the Pythagoreans, 540 BC, they actually thought that the universe played a harmony. They called it harmony of the spheres. All the planets were playing this harmony.

In the 1600s, the first astrophysicist- we’re seeing a picture of him here- Johannes Kepler, in order to come up with the three laws of the elliptical motion of all the planets, Kepler went back to the Pythagorean thinking of a musical universe.

How he figured this out was very interesting. What we’re seeing here is a sun and a planet going around an elliptical orbit. At the perihelion, where the planet is closest to the sun, the velocity was measured. The furthest from the sun, he measured the velocity.

He took the ratios of those velocities and assigned a musical note to that ratio. He did that for all the planets and came up with the scales. Through that musical thinking, he transported that into his equation.

Kepler’s three laws are still used to launch satellites into outer space and keep satellites in orbit and to still study the motion of planets today. They’re still correct.

I was very inspired by that, and said to myself, “I guess I’m going to have to use musical thinking as part of my toolkit, on top of the math and all the other stuff that I use.” I kept very interesting methods.

Now when we’re thinking about 2020, I want to tell you what the current research going on in my field is. I’m going to talk about two things and focus on one. I’m going to tell you what the cutting edge research is.

Many of you have heard about this idea called the Big Bang. This is actually Einstein’s theory of gravity. It predicts that, in the presence of matter and energy, the space-time of the universe is going to expand.

What we’re seeing, from your left to the right, that region where you have the shiny white light? That region is a big mystery. We call that the Big Bang.

We don’t understand how it came about and what happened before. That’s what I get paid to do. Thank you, taxpayers, for paying me to do these kinds of things.

What we do understand well is what happened afterwards. This red and blue area is something called a cosmic microwave background radiation, which has been measured way back in the 60s. That measurement has been confirmed up until today.

That corresponds to the earlier universe as it expanded, which was very hot and dense and filled with radiation energy, nothing else. No planets. No stars. No galaxies.

As the universe continued to expand, it cooled, and that radiation coalesced to form the first stars and galaxies that we now inhabit. We understand that physics very well, but we don’t understand what happened before the Big Bang.

Another problem we don’t understand very well is the laws of physics. We know that there are four forces of nature. All of these forces have different strengths.

What we’re looking at here is a typical star, like our sun. At the center, we see iron. Due to the immense pressure of the sun, the immense pressure forces thermonuclear fusion to transmute lighter elements into heavier elements.

A star is region or a factory that produces heavier elements, like carbon. If a star does not produce carbon, there would not be life as we know it, because we need carbon for our DNA.

It turns out if you tweak the laws of physics, these forces of strength, by a few percent, a star could never make carbon. The universe is like a perfectly fine tuned instrument, such that if it were any different, if those laws were any different, it would not produce the stuff necessary for life.
A star is what produces the stuff. We’re really made up of stardust. I want to show you a picture. That arrow is pointing at a star within a galaxy.

That star explodes into something called a supernova. It’s brighter than the entire galaxy, even though a galaxy has in the order of hundreds of billions of stars in it. That’s a picture of a star right before. That blows up all of the elements.

Here’s something really interesting: the idea of the Big Bang. Physicists today are thinking that this fine-tuning could be solved if before the Big Bang there were many bangs and there were many universes created in those bangs. We just happened to be in the universe where the coupling constants, what we call the tunings, are exactly necessary for life.

The other universes have different laws. We just hit the jackpot. Are we satisfied with that idea? This idea is what people are now working on at some of the top institutions around the world.

I returned back to my musical thinking. I said, “What if, like Kepler, the universe was more than just harmony of the sphere? What if the universe was like a jazz solo?”

In a jazz solo, as you heard these wonderful young people play, you need two things to happen. You need a rhythm section. What usually happens is that this rhythm repeats itself like a cycle. You have a harmony, and that harmonic structure repeats itself as well.

Every time that repetition happens, the improviser, the soloist, gets to try different things, gets to improvise different ideas.

What if the universe was like something like that? Instead of having one bang, the idea is that you have an infinite succession of bangs. Our past universe expanded and contracted into a bang, expanded and contracted again. Every time it did that, the universe had an opportunity to solo different laws of nature.
With this idea- because that’s what physicists do, we have an idea, as crazy as it is, and then we start putting some equations behind it- we turn back to Mr. Einstein. We go back to his equations, and we, me and my colleagues, find that the equations work out to actually say that.

I’m going to now close with some inspiration from Mr. Kaplan. As we’re thinking about 2020, I want to say to Mr. Kaplan: When I got my Ph.D. I went back to DW Clinton to thank him. I found out that he had not too long ago passed away from cancer.

That little limp that he had was because he was suffering from a terminal illness. I felt guilty. I dedicated my Ph.D. dissertation to him, but I actually felt guilty. Over those years I was so busy with my own life, I never got a chance to thank him.

That’s why I’m here to pass on the Kaplan meme. Mr. Kaplan demonstrated the courage to be true to himself. He demonstrated the courage to think differently and not fall into the traditionalism of one’s field.

He also challenged us to live a life full of improvisation. If the universe is improvising, why shouldn’t we? Thank you.